KR101010389B1 - Plasma CDD device and film formation method - Google Patents

Abstract

The film nonuniformity is eliminated in a direct current plasma CVD apparatus.

A first electrode disposed in the reactor, on which the substrate is mounted, a second electrode facing the first electrode above the first electrode, and generating a plasma between the first electrode, and the A first gas outlet disposed at a height between the height of the first electrode and the height of the second electrode, and having a plurality of ejection openings arranged to surround a region in which plasma is generated between the first electrode and the second electrode; And a gas introduction nozzle.

Plasma, spout, cathode, anode, substrate

Description

Plasma CDP device and film formation method {PLASMA CVD APPARATUS AND FILM DEPOSITION METHOD}

The present invention relates to a plasma CVD apparatus and a film formation method.

In a CVD apparatus which forms a substrate by chemical vapor deposition (CVD), a matrix gas and a reactant gas, which is a raw material gas, are introduced into a reaction tank, and the pressure in the reaction tank is kept constant by balancing the exhaust gas. I'm letting you. In a plasma CVD apparatus that generates plasma, the gas temperature is locally high, so that turbulent flow of gas occurs in the reactor.

It is preferable that the gas containing the reactive gas flows gradually and uniformly toward the substrate surface on which the film to be deposited is deposited according to the reaction of the gas. If the flow is too fast, it causes the film formation unevenness, and thus the vector of the moving direction of the reaction gas. It is known that the growth rate of the film is slowed down if it does not face the substrate.

Conventional plasma CVD apparatuses aimed at eliminating film deposition and maintaining growth rates include, for example, Japanese Patent No. 2628404, Japanese Patent Application Laid-open No. Hei 1-94615, and Yoshiyuki Abe et al., “DIAMOND SYNTHESIS BY HIGH GRAVITY D.C. PLASMA CVD (HGCVD) WITH ACTIVE CONTROL OF THE SUBSTRATE TEMPERATURE ”, Acts Astronautice (UK), 2001, Vol. 48, No. 2-3, and p. 121-127.

In the plasma CVD apparatus of Japanese Patent No. 2628404, the reaction gas is supplied from the direction parallel or inclined to the surface of the substrate, the matrix gas is supplied from the direction substantially perpendicular to the surface of the substrate, and the reaction gas is pressed by the matrix gas. The flow direction of the reaction gas is changed, and the reaction gas is blown onto the substrate surface.

By the way, this plasma CVD apparatus is a thermal plasma CVD apparatus which heats a susceptor with a heater and produces | generates a thermal plasma, and it is not necessary to make a problem of electrode placement. By the way, when an electrode is arrange | positioned in the position which opposes a board | substrate like a DC plasma CVD apparatus, it will become an obstacle and it is difficult to form a uniform flow of gas perpendicular | vertical to a board | substrate.

The plasma CVD apparatus of Japanese Patent Laid-Open No. Hei 1-94615 injects gas directly from a nozzle provided at a cathode (cathode) facing a substrate. As a result, the reaction gas can flow from the cathode to the substrate.

By the way, in this structure, the active species by reaction gas exists in high density in the nozzle part of the cathode which becomes high temperature at the time of plasma generation. For this reason, deposits accumulate gradually in the nozzle opened to the cathode, and there existed a problem that gas ejection was inhibited. In addition, when deposits grow and protrude from the vicinity of the nozzle, an electric field concentrates on the protuberances, and there is a risk of the plasma transitioning to arc discharge or spark discharge. In addition, since the gas lowered in temperature due to room temperature or expansion toward the plasma is exerted, there is also a risk of partially contracting the liquor bottle and causing film formation unevenness.

“DIAMOND SYNTHESIS BY HIGH GRAVITY D.C. PLASMA CVD (HGCVD) WITH ACTIVE CONTROL OF THE SUBSTRATE TEMPERATURE ”Plasma CVD equipment is equipped with a gas inlet at the top of the reactor and a gas exhaust at the bottom to allow the flow of gas from the cathode through the plasma and towards the anode. It is occurring.

FIG. 37 is a view for explaining the flow of the gas in the reaction tank of this plasma CVD apparatus, FIG. 37A shows the configuration of the reaction tank, and FIG. 37B shows the flow direction and the flow rate of the gas in G1 with arrows.

This plasma CVD apparatus is on the opposite side with the position of the gas inlet GI and the gas outlet GO between the center axis of the reactor as shown in FIG. 37A. For this reason, the gas toward the anode becomes dominant near the lower part of the cathode. However, as shown in FIG. 37B, a temperature difference occurs between the gas convection at the gas inlet GI side and the gas convection at the gas outlet GO side. In addition, the local pressure of the gas is also different.

In the DC plasma CVD apparatus, the partial pressure state of each component in the active species to be a film forming material varies depending on the gas temperature in the plasma, and when the temperature is high, the partial pressure value of the active species having high chemical potential is relatively low in chemical potential. Higher than the partial pressure of the species; If the temperature in the reaction tank is different, unevenness occurs in the temperature of the gas in the plasma, so there is a risk that unevenness occurs in the partial pressure of each active species depending on the place, resulting in uneven deposition.

As described above, the plasma CVD apparatus of Japanese Patent No. 2628404 is a thermal plasma CVD apparatus that generates a thermal plasma by heating a susceptor with a heater. When an electrode is disposed at a position facing the substrate, such as a DC plasma CVD apparatus. It was difficult to form a uniform gas flow with respect to the substrate.

In addition, the plasma CVD apparatus of Japanese Patent Laid-Open No. Hei 1-94615 has a possibility that a problem may occur when forming a film, and there is a risk of uneven film formation, which is not technically satisfactory.

In addition, "DIAMOND SYNTHESIS BY HIGH GRAVITY D.C. The plasma CVD apparatus of PLASMA CVD (HGCVD) WITH ACTIVE CONTROL OF THE SUBSTRATE TEMPERATURE ”was incomplete in the uniformity of the gas supplied to the substrate.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a plasma CVD apparatus and a film forming method for uniformly supplying a reaction gas to the surface of a substrate and enabling stable film formation even when there is an electrode at a position facing the substrate. For the purpose of

A plasma CVD apparatus according to a first aspect of the present invention is disposed in a reaction tank, and faces a first electrode on which a substrate is mounted, facing the first electrode above the first electrode, and between the first electrode and the plasma. And a region arranged at a height between the height of the second electrode and the height of the first electrode in the reactor and the height of the second electrode in the reactor, and where the plasma is generated between the first electrode and the second electrode. And a first gas introduction nozzle having a plurality of ejection openings arranged to surround the second electrode, wherein the second electrode includes a plurality of electrodes, and a voltage or a current between each electrode of the second electrode and the first electrode Each of them is individually set to a predetermined value.

The first gas introduction nozzle may include a source gas in which active species are formed by the plasma.

In addition, the first gas introduction nozzle may include a source gas and a matrix gas in which active species are formed by the plasma.

Moreover, it is preferable that a said 1st gas introduction nozzle blows a gas in the horizontal direction toward the center axis of the said 1st electrode from the said some injection port.

Moreover, it is preferable that the said 1st gas introduction nozzle is arrange | positioned so that the periphery of the said 1st electrode may be enclosed.

Moreover, it is preferable that the said some injection port of the said 1st gas introduction nozzle is arrange | positioned at equal intervals mutually.

In addition, it is preferable that the plurality of ejection openings of the first gas introduction nozzle have the same distance from the central axis of the first electrode.

Moreover, it is preferable that the jet port of each tank which consists of two of the said jet nozzles of the said 1st gas introduction nozzle is mutually opposing each other centering on the central axis of the said 1st electrode.

Moreover, it is preferable that the height of the said blower outlet of the said 1st gas introduction nozzle is in the position higher than the highest point of the area | region where the positive wine column of the said plasma generate | occur | produces.

The first gas introduction nozzle may be in a ring shape or may be a tube facing each other along the side of the second electrode in the reactor.

Moreover, you may be provided with the 2nd gas introduction nozzle which blows a matrix gas from the upper side of the said 2nd electrode toward the gas blown out from the said 1st gas introduction nozzle.

It is preferable that a plurality of discharge pipes are arranged below the first electrode and discharge gas from the reaction tank.

In particular, the plurality of discharge conduits are preferably arranged to surround the periphery of the first electrode.

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In this case, the plurality of electrodes is composed of a central electrode facing the central portion of the first electrode and a peripheral electrode facing the peripheral portion of the first electrode, and at the rising, the central electrode at the start of the predetermined process. The voltage or current value between the first electrode and the first electrode may be set higher than the voltage or current value between the peripheral electrode and the first electrode.

The plurality of electrodes may include the center electrode facing the central portion of the first electrode and a peripheral electrode facing the peripheral portion of the first electrode, and a positive light column may be disposed between the center electrode and the first electrode. After formation, the voltage or current value between the center electrode and the first electrode may be less than the voltage or current value between the peripheral electrode and the first electrode.

Moreover, it is preferable that the insulator is arrange | positioned between the said some electrode.

The plasma CVD apparatus has a substrate placing surface on which a substrate to be processed is mounted, and a recess for accommodating the substrate is formed in the substrate placing surface, an electrode having a surface formed of graphite, and a part of the electrode And plasma generating means for forming a carbon film on the substrate by generating a plasma on the electrode using hydrocarbon as a reaction gas in a state exposed to the periphery of the substrate.

According to the film forming method of the present invention, a predetermined electrode is separately provided between a first electrode on which a substrate is mounted and a second electrode composed of a plurality of electrodes, between each electrode of the second electrode and the first electrode. A voltage or a current set to a value is applied, and the reaction gas is blown out from a plurality of blowing holes arranged to surround a region where plasma is generated.

According to the present invention, the effect of eliminating the unevenness in film formation in the direct current plasma CVD apparatus is obtained.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described based on drawing.

[First embodiment]

1 is a configuration diagram showing an outline of a plasma CVD apparatus according to a first embodiment of the present invention.

This DC plasma CVD apparatus is an apparatus which forms a film on the surface of the board | substrate 1 of a process object, and is equipped with the chamber 10 which is a reaction tank. The chamber 10 isolates the substrate 1 from the outside air.

In the chamber 10, a columnar steel stage 11 is disposed, and a disk-shaped thermal conductivity is good on the upper portion of the stage 11, and a melting point, for example, made of molybdenum or graphite The anode 11a is mounted. The diameter of the anode 11a is 80 mm, for example, and thickness is 20 mm. The board | substrate 1 is rectangular and is fixed to the upper mounting surface of the anode 11a. The stage 11 is set to rotate about the axis 11x with the anode 11a.

The closed space 11b is provided in the stage 11 below the anode 11a, and the cooling member 12 is disposed in the space 11b. The cooling member 12 is provided in order to cool the board | substrate 1 as needed, and is structured so that the cooling member 12 can move up and down like an arrow by the moving mechanism which is not shown in figure. The cooling member 12 is made of a metal having high thermal conductivity such as copper, and inside the cooling medium such as cooled water or cooled calcium chloride aqueous solution is transferred from the conduit 12a to the flow path 12b in the cooling member 12. It enters and circulates so that it may be discharged | emitted from the conduit 12c, and the cooling member 12 whole is cooled.

For this reason, when the cooling member 12 moves upwards, the upper surface 1 of the cooling member 12 abuts on the lower surface of the stage 11, and the stage 11 which abuts is the anode of the upper part ( The structure 11a is cooled and the anode 11a takes the heat of the board | substrate 1 into consideration. The cooling medium discharged from the conduit 12c is cooled by a cooling device (not shown) and circulated so as to be sent out to the conduit 12c again. Since the upper surface of the cooling member 12 cools the board | substrate 1 evenly to a surface direction, it is preferable to be larger than the board | substrate 1 further.

In addition, the space 11b provided below the anode 11a is partitioned by the stage 11, and gas is enclosed in the inside or it is in the air-opened state.

The disk-shaped negative electrode 13 is arrange | positioned above the positive electrode 11a. The negative electrode 13 is supported by the negative electrode support 14, and the negative electrode 13 and the positive electrode 11a face each other. The cathode 13 is formed of molybdenum, graphite, or the like having a high melting point. For example, the cathode 13 is 80 mm in diameter and 20 mm in thickness. The negative electrode support body 14 is comprised from heat resistant oxides, such as quartz glass and alumina, heat resistant nitrides, such as aluminum nitride and silicon nitride, or heat resistant carbides, such as silicon carbide. The distance between the cathode 13 and the anode 11a is 50 mm, for example.

The flow path through which the cooling medium flows may be formed inside the cathode 13. Overheating of the cathode 13 can be suppressed by the flow of the cooling medium. As a cooling medium, water, calcium chloride aqueous solution, etc. which are introduce | transduced from the exterior of the chamber 10 are preferable.

In the vicinity of the outer circumferential surface of the anode 11a, an insulating portion 15 for suppressing generation of arc is disposed. The insulating portion 15 is composed of at least one of heat resistant oxides such as quartz glass and alumina, heat resistant nitrides such as aluminum nitride and silicon nitride, and heat resistant carbides such as silicon carbide.

The insulating part 15 is ring-shaped, is supported by the support body 16 standing up at the bottom of the chamber 10 at the same height as the anode 11a, and surrounds the outer circumference of the anode 11a on the inner circumferential side thereof. . The outer diameter of the insulating portion 15 is 1.2 times or more the length of the outermost diameter of the cathode 13.

Since the insulating part 15 suppresses the occurrence of abnormal discharge (arc discharge, spark discharge) between the negative electrode 13 and the positive electrode 11a, the insulating portion 15 is disposed along the outer circumferential side of the negative electrode 13. It is mounted toward. In addition, the insulating part 15 may hide the side surface of the positive electrode 11a with respect to the negative electrode 13.

The window 17 is formed in the side surface of the chamber 10, and the observation in the chamber 10 is attained. The heat resistant glass is inserted into the window 17, and the airtightness in the chamber 10 is ensured. Outside the chamber 10, a radiation thermometer 18 is arranged which measures the temperature of the substrate 1 via the glass of the window 17, for example.

This DC plasma CVD apparatus discharges gas from a raw material system (not shown) for introducing a source gas containing a reaction gas through a gas tube 19 and from inside the chamber 10 through a plurality of exhaust conduits 20. And an exhaust system (not shown) for adjusting the air pressure in the chamber 10, and a voltage setting unit 21.

The gas tube 19 is introduced into the chamber 10 through a hole provided in the chamber 10, and at least a part of the gas tube 19 in the reaction tank is made of an insulator such as fluororesin or silicone rubber. Between the hole of a chamber and the outer periphery of the gas tube 19 is sealed with the sealing material, and the airtightness in the chamber 10 is ensured. In the chamber 10, the gas tube 19 is connected to the ring nozzle 22 which is a gas introduction nozzle. The ring nozzle 22 is preferably in a round shape, but may be a regular polygon.

2 is an explanatory view of the ring nozzle 22 and the exhaust conduit 20.

The ring nozzle 22 is hollow in its entirety in a ring shape and flows through the source gas. On the inner circumferential surface side of the ring nozzle 22, a plurality of ejection openings 22a having the same diameter are arranged at equal intervals. The plurality of ejection openings 22a are also equal to each other in the distance between the shaft 11x, which is the central axis of the anode 11a, and the individual ejection openings 22a are also ejected at opposite positions centering on the shaft 11x. It is provided in point symmetry so that 22a may oppose each other. As described above, the plurality of ejection openings 22a are formed to surround the region where the plasma is generated, and the source gas is ejected evenly from the ejection opening 22a toward the shaft 11x.

The ring nozzle 22 is supported by the nozzle support 23 of the insulator attached to the cathode support 14. The ejection opening 22a of the ring nozzle 22 is lower than the height of the anode 11a at a position lower than the lowermost part of the cathode support 14 (the uppermost part on the side exposed from the cathode support 14 of the cathode 13). It is set at a position higher than the highest point of the positive light column PC generated between the positive electrode 11a and the negative electrode 13. When the ring nozzle 22 is supported in this range, it is easy for the source gas to enter between the cathode 13 and the anode 11a, and locally cools the gas temperature in the bright wine PC by the source gas. It can prevent.

The inner diameter of the ring nozzle 22 is larger than the outer diameter of the negative electrode 13 and the outer diameter of the positive electrode 11a. The center of the ring nozzle 22 is on the axis 11x of the anode 11a. The angles gazing at each jet port 22a from the center of the anode 11a are substantially equal.

The four exhaust conduits 20 penetrate through the four holes opened at equal intervals to surround the stage 11 or the anode 11a around the shaft 11x at the bottom surface of the chamber 10, respectively. Doing. The sealing member is sealed between the hole and the outer circumference of the exhaust pipe 20.

The voltage setting section 21 is a control device for setting a voltage or current value between the positive electrode 11a and the negative electrode 13, and includes a variable power supply 21b. The voltage setting section 21, the positive electrode 11a and the negative electrode 13 are connected by lead wires, respectively. Each lead wire passes through a hole provided in the chamber 10 and is connected to the cathode 13 and the anode 11a, respectively. The hole of the chamber 10 through which the lead wire passed is sealed with the sealing material.

The voltage setting unit 21 includes a control unit 21a, which is connected to the radiation thermometer 18 by a lead wire, and is connected by a variable power source 21b and a lead wire. When the control part 21a is started, it references the temperature of the board | substrate 1 measured by the radiation thermometer 18, and between the anode 11a and the cathode 13 so that the temperature of the board | substrate 1 may become a predetermined value. Adjust the voltage or current value.

Next, a film forming process of forming a film on the substrate 1 using the direct current plasma CVD apparatus of FIG. 1 will be described.

In this film forming process, an electron-emitting film made of carbon nanowalls is formed on the surface of the substrate 1.

The carbon nanowall is formed by connecting a plurality of carbon flakes in the shape of a petal (liquid) constituting a curved surface in a random direction. Each carbon flake is composed of several layers to several tens of graphene sheets having a lattice spacing of 0.34 nm.

In the film forming process, first, for example, the nickel plate is cut out as the substrate 1, and degreasing / ultrasound washing is sufficiently performed with ethanol or acetone. When the surface of the board | substrate 1 is formed with the metal, the surface of the board | substrate 1 is covered very thinly with many insulating fine particles with a high melting point and small diameter like microparticles | fine-particles and aluminum oxide microparticles | fine-particles. This is because when the surface of the substrate 1 is formed of metal, active species of the source gas diffuse into the substrate 1, and there is a problem that deposits by the active species are less likely to be deposited on the surface of the substrate 1. However, by covering the surface of the substrate 1 extremely thinly with a large number of insulating fine particles, deposits can be deposited from the surface of the insulating fine particles without almost blocking the boundary between the positive electrode 11a and the negative electrode 13. have.

The substrate 1 is mounted on the anode 11a.

After the mounting of the substrate 1 is completed, the chamber 10 is then decompressed using an exhaust system, and then, as a source gas, a compound containing carbon in a composition such as hydrogen gas and methane from the gas tube 19. The reaction gas (carbon-containing compound) of is sent. The source gas is ejected from the ejection port 22a of the ring nozzle 22.

It is preferable that the reaction gas containing carbon in the composition in source gas exists in the range of 3 vol%-30 vol% of the whole. For example, the flow rate of methane is 50 SCCM, the flow rate of hydrogen is 500 SCCM, and the total pressure is 0.05 to 1.5 atm, preferably 0.07 to 0.1 atm. Further, the anode 11a is rotated at 1 rpm for each substrate 1 with the axis 11x as the axis, and the temperature nonuniformity on the substrate 1 is within 5%, between the anode 11a and the cathode 13. A DC power source is applied to generate a plasma to control the plasma state and the temperature of the substrate 1.

At the time of film-forming of carbon nanowall, film formation of predetermined time is performed at 900 degreeC-1100 degreeC in the temperature of the location where the carbon nanowall of the board | substrate 1 is formed. This temperature is measured by the radiation thermometer 18. At this time, the cooling member 12 is sufficiently separated from the anode 11a so as not to affect the temperature of the anode 11a. The radiation thermometer 18 is set to subtract the plasma radiation of the direct-current plasma CVD apparatus to obtain a temperature from only heat radiation on the surface of the substrate 1 side.

In the process of forming the carbon nanowall, for example, the film quality of the electron-emitting film is changed, and when the diamond layer including a plurality of diamond fine particles is laminated on the carbon nanowall, the cooling member 12 is raised on the anode 11a. Make contact. Thereby, the temperature of the board | substrate 1 can be cooled dramatically, and a diamond layer can be laminated | stacked. With the formation of the diamond layer, sp ² bond carbon in which cores are accumulated is grown from the gap of the diamond layer in the shape of a rod in which a part of the carbon nanowall is deformed, and unlike the carbon nanotubes. The rod-shaped carbon extends so as to protrude from the surface of the diamond layer, and is structurally easy to concentrate on electric field and becomes a site for emitting electrons.

At the end of film formation, the application of the voltage between the anode 11a and the cathode 13 is stopped, the supply of source gas is subsequently stopped, and nitrogen gas is supplied into the chamber 10 as a purge gas to supply the chamber 10. The inside of the inside) is placed in a nitrogen atmosphere, and the substrate 1 is taken out in the state of returning to normal temperature.

The DC plasma CVD apparatus according to the present embodiment described above has the following advantages [1] to [6].

[1] The ring nozzle 22 is disposed in the chamber 10, and the source gas is blown horizontally, that is, in the inner transverse direction, from the jet port 22a of the ring nozzle 22 toward the shaft 11x, and the four exhausts are discharged. It exhausts from the pipeline 20. Since the jet port 22a is arranged at equal intervals in the ring nozzle 22, and the exhaust conduit 20 is arranged at equal intervals around the stage 11, the flow of source gas flows in the chamber 10. The axis 11x is symmetrically equalized. In addition, since the cathode 13 and the cathode support 14 do not disturb the flow of the source gas, the cathode 13 and the cathode support 14 flow efficiently to just below the center of any cathode 13 of the shaft 11x, and the end on the substrate 1 The raw material gas spreads evenly from the center until it reaches the center, and the density of active species generated from the raw material gas in the bright wine PC is equalized, and the film can be formed evenly on the surface of the substrate 1.

Here, the result of having investigated the influence by the difference of the flow method of source gas by experiment is demonstrated.

3A and 3B are views for explaining the configuration of the direct current plasma CVD apparatus used in the comparative experiment.

FIG. 4A is a diagram showing a state of glow generated in the cathode in the DC plasma CVD apparatus shown in FIGS. 3A and 3B. FIG. 4B is a diagram showing a glow state occurring in the cathode in the DC plasma CVD apparatus according to the first embodiment.

In this experiment, a part of the DC plasma CVD apparatus of FIG. 1 is used so that the flow of source gas does not become symmetrical to the axis 11x, and the cathode 13 becomes a three-dimensional obstacle between the anode 11a and the nozzle. It is changed to be deployed. For example, as shown in FIG. 3B, the ring nozzle 22 and the nozzle support 23 are removed from the chamber 10, and the gas tube 19 is disposed above the cathode support 14 of the chamber 10. One gas shower nozzle 25 is connected, and the gas is ejected downward from the gas shower nozzle 25 in a shower shape, and the other exhaust pipe line 20 is left in the other exhaust pipe line 20 with only one exhaust pipe line 20 remaining therein. For example, the stopper 24 is provided, and exhausting from the exhaust conduit 20 with the stopper 24 is prevented. The other configuration is the same as that of the direct current plasma CVD apparatus of FIG. In addition, in order to show the effect by the positions of the inlet and the outlet of the source gas on the movement of the source gas which is a fluid, the insulation section 15 is similar to the DC plasma CVD apparatus of this embodiment also in the DC plasma CVD apparatus of the comparative experiment. ) Is being installed.

In the DC plasma CVD apparatus modified as shown in FIG. 3B and the DC plasma CVD apparatus of FIG. 1, the state of glow generated under the cathode 13 was observed. In addition, the source gas is hydrogen, the gas flow rate is 500 sccm, the gas pressure is 30torr, and the current flowing in the cathode 13 is 2A.

In the DC plasma CVD apparatus modified as in FIG. 3B, the raw material gas ejected from the gas shower nozzle 25 is discharged toward the one exhaust pipe 20 which is not provided with a stopper 24. As shown in FIG. 3B, the exhaust pipe line does not radially flow, and no gas flows symmetrically with respect to the axis 11x even below the cathode 13 and does not have a stopper 24 as indicated by the double-dotted line in FIG. 3B. The flow of source gas concentrates toward (20). In addition, since the cathode 13 becomes a steric hindrance to the flow of the source gas, it is difficult to return to the cathode 13 and reach the axis 11x at the center of the anode 11a, so that the surface of the substrate 1 In-plane nonuniformity occurs in the active species density that is reached. This nonuniformity becomes remarkable as the cathode 13 or the anode 11a is enlarged as the substrate 1 is enlarged.

Therefore, in the DC plasma CVD apparatus of FIG. 3B, as shown in FIG. 4A, the inclination occurs in the shape of the cathode glow generated in the cathode 13. Inclination in the shape of the cathode glow generated in the cathode 13 indicates that the temperature distribution is also inclined, and there is a risk of unevenness in the film formation on the substrate 1. On the other hand, in the DC plasma CVD apparatus of FIG. 1, as shown in FIG. 4B, no inclination occurs in the glow generated in the cathode 13. Therefore, uniform film formation with respect to the board | substrate 1 is possible.

[2] Since the gas tube 19 is made of an insulator, the ring nozzle 22 is supported by the nozzle support 23 of the insulator, and the ring nozzle 22 is insulated from the power source or the gland, the cathode 13 Or there is no occurrence of unnecessary arc discharge from the anode 11a.

[3] Since the inner diameter of the ring-shaped ring nozzle 22 is larger than the outer diameter of the negative electrode 13 or the positive electrode 11a, a high density liquor of active species between the negative electrode 13 or the positive electrode 11a Since the ring nozzle 22 does not overlap with PC, the temperature rise of the part of the jet nozzle 22a of the ring nozzle 22 by plasma is small, and generation | occurrence | production of a deposit in the jet nozzle 22a is suppressed.

[4] Since the height of the spout port 22a of the ring nozzle 22 is higher than the highest point of the Yangzhou liquor PC, the gas temperature of the Yangju Liquor PC is partially cooled by the low temperature gas ejected from the jet port 22a. We do not do it and do not disturb the symmetry of the shape of the Yanggwangju PC.

[5] The insulator 15 prevents the occurrence of arc discharge that inhibits uniform film formation from the cathode 13 toward the outer circumference of the anode 11a.

[6] The ring nozzle 22 is disposed at the same or lower position as the electrode surface of the cathode 13, and the source gas discharged from the ring nozzle 22 in the lateral direction is transferred to the exhaust pipe 20 for the lower side. Since it is attracted, the contact with the cathode 13 can be prevented by diffusion of a highly reactive active tank generated in the Yangju wine PC. Therefore, it is possible to prevent deposition by active species on the negative electrode 13 which causes arc discharge or sparks.

Second Embodiment

5A and 5B are structural diagrams of the DC plasma CVD apparatus according to the second embodiment of the present invention, in which elements common to those in FIG. 1 are denoted by the same reference numerals.

In this DC plasma CVD apparatus, the cathode 13 of the DC plasma CVD apparatus of FIG. 1 is changed to the cathode 27, and the voltage setting unit 21 is changed to the voltage setting unit 28.

The cathode 27 is a disk-shaped center electrode 27a facing the center of the anode 11a, and a ring shape (see FIG. 5B) surrounding the outer periphery of the center electrode 27a, and is concentric with the center electrode 27a. At the same time, it has a peripheral electrode 27b facing the periphery of the anode 11a, and an insulating portion 27c such as ceramic filled with no gap between the central electrode 27a and the peripheral electrode 27b. .

In the case where the insulating portion 27c is not interposed between the center electrode 27a and the peripheral electrode 27b, the substrate 1 is not provided with a sufficiently long distance between the center electrode 27a and the peripheral electrode 27b. In addition, the electric field strength at the side wall of the center electrode 27a and the side wall of the peripheral electrode 27b facing each other is weakened, and a portion not covered with the cathode glow occurs. In this part, since the bombardment of ions becomes small, a deposit wants to deposit. These deposits cause arc discharges or spark discharges. For this reason, by interposing the insulating portion 27c, the film is prevented from being deposited on the sidewall of the center electrode 27a and the sidewall of the peripheral electrode 27b which face each other.

The voltage setting section 28 includes a control section 28a and variable power supplies 28b and 28c.

The control unit 28a is connected to the radiation thermometer 18 by a lead wire. The control unit 28a controls the variable power sources 28b and 28c and controls the voltage or current between the anode 11a and the center electrode 27a and the voltage between the anode 11a and the peripheral electrode 27b. It has the function of setting the current individually. The other configuration is the same as that of the direct current plasma CVD apparatus of FIG.

In the case of forming the film on the substrate 1 using the DC plasma CVD apparatus of FIG. 5, when the plasma rises, the substrate 1 is rotated at 1 rpm, and the anode 11a and the center are controlled by the voltage setting unit 28. The voltage difference between the cathode 27 and the anode 11a is set so that the potential difference between the electrodes 27a is larger than the potential difference between the anode 11a and the peripheral electrode 27b. By applying such a voltage application method, a small positive column PC is generated between the anode 11a and the center electrode 27a. As a result, it is possible to prevent the occurrence of arc discharge that frequently occurs when generating a large positive liquor from the beginning.

In this way, after the stable positive liquor PC is formed on the upper portion of the center portion of the substrate 1 by the application of voltage or current, the controller 28a determines the voltage or current value between the anode 11a and the center electrode 27a. A voltage or a current is applied so that the voltage between the anode 11a and the peripheral electrode 27b is less than the voltage or less than the current value, whereby the temperature between the anode 11a and the center electrode 27a and the anode ( A film is formed on the substrate 1 by approximating or roughly matching the temperature between 11a) and the peripheral electrode 27b.

As described above, in the present embodiment, the cathode 27 is composed of the center electrode 27a and the peripheral electrode 27b, and the voltage or current value between the anode 11a and the center electrode 27a, and the anode 11a. ) And the voltage or current between the peripheral electrode 27b can be set independently. When the plasma rises, the voltage between the anode 11a and the center electrode 27a is made higher than the voltage between the anode 11a and the peripheral electrode 27b. This makes it possible to shorten the distance between the anode 11a and the cathode 27 to form a positive column PC. The voltage applied to the positive electrode 11a and the negative electrode 27 may be low, and the frequency of occurrence of arc discharge or spark discharge can be suppressed.

In addition, with respect to the current flowing through the center electrode 27a, the current flowing through the peripheral electrode 27b is reduced so that a positive light column PC concentrated in the center of the substrate 1 is generated, and then the peripheral electrode 27b is generated. By increasing the current to be applied to the peripheral electrode 27b to increase the power to be applied, local arc discharge occurring at the beginning of film formation can be prevented, and then the positive light column PC can be formed into a required size.

[Third Embodiment]

The structural example of the direct current plasma CVD apparatus which concerns on 3rd Embodiment of this invention is shown in FIG. In FIG. 6, the same code | symbol is attached | subjected to the element common to the DC plasma CVD apparatus of 1st Embodiment of FIG.

This DC plasma CVD apparatus is equipped with the chamber 30 which is a reaction tank. The chamber 30 isolates the substrate 1 from the outside air.

In the chamber 30, a columnar forced stage 11 is arranged, and a disk-shaped thermal conductivity is good on the upper part of the stage 11, and a high melting point, for example, molybdenum or graphite anode 11a is formed. It is mounted. The board | substrate 1 is rectangular and is fixed to the upper mounting surface of the anode 11a. The stage 11 is set to rotate about the axis 11x with the anode 11a.

The closed space 11b is provided in the stage 11 below the anode 11a, and the cooling member 12 is disposed in the space 11b. The cooling member 12 is provided in order to cool the board | substrate 1 as needed, and is structured so that the cooling member 12 can move up and down like an arrow by the moving mechanism which is not shown in figure. The cooling member 12 is made of a metal having high thermal conductivity such as copper, and inside the cooling medium such as cooled water or cooled calcium chloride aqueous solution is transferred from the conduit 12a to the flow path 12b in the cooling member 12. It enters and circulates so that it may be discharged | emitted from the conduit 12c, and the cooling member 12 whole is cooled.

For this reason, when the cooling member 12 moves upwards, the upper surface 1 of the cooling member 12 abuts on the lower surface of the stage 11, and the stage 11 which abuts is the anode of the upper part ( The structure 11a is cooled and the anode 11a takes the heat of the board | substrate 1 into consideration. The cooling medium discharged from the conduit 12c is cooled by a cooling device (not shown) and circulated so as to be sent out to the conduit 12a again.

The disk-shaped negative electrode 13 is arrange | positioned above the positive electrode 11a. The negative electrode 13 is supported by the negative electrode support 14, and the negative electrode 13 and the positive electrode 11a face each other. The cathode 13 is made of molybdenum, graphite, or the like having a high melting point. The negative electrode support body 14 is comprised from heat resistant oxides, such as quartz glass and alumina, heat resistant nitrides, such as aluminum nitride and silicon nitride, or heat resistant carbides, such as silicon carbide.

The flow path through which the cooling medium flows may be formed inside the cathode 13. Overheating of the cathode 13 can be suppressed by the flow of the cooling medium.

In the vicinity of the outer circumferential surface of the anode 11a, an insulating portion 15 for suppressing generation of arc is disposed. The insulating portion 15 is composed of at least one of heat resistant oxides such as quartz glass and alumina, heat resistant nitrides such as aluminum nitride and silicon nitride, and heat resistant carbides such as silicon carbide.

The insulating part 15 is ring-shaped, is supported by the support body 16 standing up at the bottom of the chamber 10 at the same height as the anode 11a, and surrounds the outer circumference of the anode 11a on the inner circumferential side thereof. . The outer diameter of the insulating portion 15 is 1.2 times or more the length of the outermost diameter of the cathode 13.

In addition, the insulating portion 15 suppresses the occurrence of abnormal discharge (arc discharge, spark discharge) between the cathode 13 and the anode 11a, and faces the cathode 13 along the outer circumferential side of the anode 11a. The side surface of the positive electrode 11a may be hidden with respect to the negative electrode 13.

The window 17 is formed in the side surface of the chamber 10, and the observation in the chamber 30 is possible. The heat resistant glass is inserted in the window 17, and the airtightness in the chamber 30 is ensured. Outside the chamber 30, a radiation thermometer 18 is arranged which measures the temperature of the substrate 1 via, for example, the glass of the window 17.

In this DC plasma CVD apparatus, a reaction gas system (not shown) for introducing a reactive gas, which is a raw material of active species, through the gas tube 31 and a raw material system for introducing a matrix gas (carrier gas) through the gas tube 32. (Not shown) and an exhaust system (not shown) for discharging gas from the chamber 30 through the plurality of exhaust conduits 20 to adjust the air pressure in the chamber 30, and a voltage setting unit 21. have.

The gas tube 31 is comprised from the insulator and passes through the hole provided in the chamber 30. Between this hole and the outer periphery of the gas tube 31 is sealed with the sealing material, and the airtightness in the chamber 30 is ensured. The gas tube 31 is connected to the ring nozzle 33 in the chamber 30.

The ring nozzle 33 is similar to the ring nozzle 22 shown in FIG. 2, and a plurality of ejection openings 33a having the same diameter are arranged at equal intervals on the inner peripheral surface of the ring shape of the ring nozzle 33. The ejection opening 33a is also equal to each other with a distance between the axis 11x which is the central axis of the anode 11a. The individual ejection openings 33a are provided in point symmetry such that the ejection openings 33a are opposed to each other at opposite positions centering on the shaft 11x, and the source gas is ejected evenly from the ejection opening 33a toward the shaft 11x. do.

The ring nozzle 33 is supported by the nozzle support 23 of the insulator attached to the cathode support 14. The height at which the ring nozzle 33 is supported is equal to or less than the lowermost part of the blower outlet 33a (the uppermost part on the side exposed from the negative electrode support 14 of the negative electrode 13) and the positive electrode 11a and the negative electrode ( It is set at a position higher than the highest point of the Yanggwangju PC that occurs between 13). When the ring nozzle 33 is supported in this range, the raw material gas is likely to enter between the cathode 13 and the anode 11a, and is produced by locally cooling the gas temperature in the bright wine column PC by ejecting the reaction gas. The disturbance of the symmetry of the positive light column PC can be suppressed.

The inner diameter of the ring nozzle 22 is larger than the outer diameter of the negative electrode 13 and the outer diameter of the positive electrode 11a. The center of the ring nozzle 33 is on the axis 11x of the anode 11a. The angles gazing at each outlet 33a from the center of the anode 11a are substantially equal.

The four exhaust conduits 20 penetrate through the four holes opened at equal intervals so as to surround the stage 11 about the axis 11x at the bottom surface of the chamber 30, respectively. The sealing member is sealed between the hole and the outer circumference of the exhaust pipe 20.

The voltage setting section 21 is a control device for setting a voltage or current value between the positive electrode 11a and the negative electrode 13, and includes a variable power supply 21b. The voltage setting section 21, the positive electrode 11a and the negative electrode 13 are connected by lead wires, respectively. Each lead wire passes through a hole provided in the chamber 30 and is connected to the cathode 13 and the anode 11a, respectively. The hole of the chamber 30 through which the lead wire passed is sealed with the sealing material.

The voltage setting unit 21 includes a control unit 21a, which is connected to the radiation thermometer 18 by a lead wire, and is connected by a variable power source 21b and a lead wire. When the control part 21a is started, it references the temperature of the board | substrate 1 measured by the radiation thermometer 18, and the voltage between the anode 11a and the cathode 13 so that the temperature of the board | substrate 1 may become a predetermined value. Or adjust the current value.

The gas tube 32 consists of an insulator, and passes through the hole provided in the chamber 30. The airtightness in the chamber 30 is ensured between the hole and the outer periphery of the gas tube 32 with the sealing material. In the chamber 30, the gas tube 32 is connected to the gas shower nozzle 34.

The gas shower nozzle 34 is located above the cathode support 14 supporting the cathode 13 and above the ring nozzle 33, and a plurality of ejection openings having the same diameter on the lower surface is centered on the shaft 11x. Therefore, they are formed concentrically or radially. In addition, the individual jets are provided in point symmetry such that the jet ports face each other at opposite positions centering on the shaft 11x, and blow out the matrix gas downward in a shower shape.

The basic operation | movement at the time of forming into a film using the DC plasma CVD apparatus of this embodiment is the same as that of using the DC plasma CVD apparatus of 1st Embodiment. In the DC plasma CVD apparatus of this embodiment, however, the matrix gas and the reaction gas are introduced independently, the reaction gas is ejected from the ring nozzle 33 in the inner transverse direction, and the matrix gas is discharged from the gas shower nozzle 34. Ejected downward. The matrix gas changes the vector of the flow of the reaction gas ejected in the transverse direction and is inclined toward the substrate 1 so as to flow toward the substrate 1 below.

Here, the verification experiment about the height of the ring nozzle 33 is demonstrated.

7 is a diagram illustrating an outline of a verification experiment.

In this verification experiment, the diameters of the positive electrode 11a and the negative electrode 13 were 160 mm, these heights were 15 mm, respectively, and the distance between the positive electrode 11a and the negative electrode 13 was 60 mm, and the ring nozzle 33 The matrix gas discharged from the gas shower nozzle 34 with the inner diameter of 305 mm and the tube diameter of 0.25 inch, the distance between the lower surface of the gas shower nozzle 34 and the lower surface of the cathode 13 being 260 mm. 600 sccm of hydrogen, 48 sccm of argon of the matrix gas, 60 sccm of methane of the reaction gas discharged from the spout 33a of the ring nozzle 33, 60 Torr of gas pressure, the cathode 13 and the anode 11a. A current of 16A) is used, a silicon substrate having a square of 0.7 mm and a thickness of 0.7 mm is used as the substrate 1, the film formation time is 2 hours, and the height of the ring nozzle 33 is changed. Film formation was performed. As shown in FIG. 7, when the position of the blower outlet 33a of the ring nozzle 33 is in the position of 10 mm down from the lower surface of the cathode 13, it is 10 mm upward from the upper surface of the anode 11a. The position is set to low when the position is at.

8 and 9 illustrate the results of the verification experiment. In this verification experiment, the observation point A located in the center of the board | substrate 1 shown in FIG. 8 and located on the axis | shaft 11x, and the distance L1 from arbitrary cross sections of the board | substrate 1 shall be 10 mm, and this arbitrary cross section The observation of the growth of a carbon nanowall was performed at observation point B which made distance L2 from 2 cross sections adjacent to 37.5 mm.

In addition, the growth of carbon nanowalls was observed on the substrate 1 in both the case where the reaction gas was discharged from the position high and when the reaction gas was discharged from the position low.

9 (a) and 9 (c) show carbon nanos at observation point A and observation point B when plasma CVD is performed for two hours when the position of the jet port 33a of the ring nozzle 33 is at the position high, respectively. It is a single-layer SEM image showing the growth of the month. 9 (b) and 9 (d) show carbon nanos at observation point A and observation point B when plasma CVD is performed for 2 hours when the position of the jet port 33a of the ring nozzle 33 is at the position low, respectively. It is a single-layer SEM image showing the growth of the month.

As shown in Figs. 9A and 9C, when the reaction gas was released only from the position high, there was no difference in the degree of growth of the carbon nanowall at the observation point A and the observation point B. On the other hand, when the reaction gas was discharged only from the position low, the difference was seen as shown in Figs. 9B and 9D, and the carbon nanowall was larger in the observation point B than in the observation point A.

This means that in the case of the position low, the reaction gas ejected from the ring nozzle 33 is too low to reach the viewpoint A as compared with the case of the position high, and in order to cool the temperature of the periphery in the plasma outside the center, The cause is considered to be a large difference in the temperature of the gas at the center and the periphery in the plasma. The decrease in the gas temperature in the plasma near the outer periphery of the substrate 1 also leads to an increase in the density of the active species having a relatively low chemical potential, resulting in uneven film formation.

On the other hand, in the case of the position high, since the low-temperature reaction gas is not blown directly to the Yangju winemaker PC, the temperature gradient in the gas is small, and film formation unevenness does not occur.

Next, the experiment which observes the film-forming state by changing the diameter of the blower outlet 33a is demonstrated.

The position of the ring nozzle 33 is set to the position of the position high shown in FIG. 7, and the diameter of the jet port 33a is changed to 0.5 mm, 1.0 mm, and 1.5 mm to change the emissivity on the surface of the substrate. Measured. In the case of depositing an aggregate of graphite structures such as carbon nanowalls on a silicon substrate, as the film thickness increases, emissivity generally tends to increase. In addition, the movement speed of the gas immediately after the ejection when the diameter of the ejection opening 33a is 0.5 mm is 500 cm / s, and the movement speed of the gas immediately after the ejection when the diameter of the ejection opening 33a is 1.0 mm is 125 cm / s. The flow rate of the gas immediately after the ejection when the diameter of the ejection port 33a is 1.5 mm is set to 55 cm / s, and the flow rate of the reaction gas per unit time is made equal.

10 (a), 10 (b) and 10 (c) each show a plasma CVD apparatus in which the diameters of the ejection openings 33a of the ring nozzles 33 at positions high are 0.5 mm, 1.0 mm, and 1.5 mm, respectively. It is an SEM cross-sectional view which shows the film-forming state in observation point A (substrate center) shown in FIG. 8 at the time plasma CVD process is performed. FIG. 11: is a figure which shows the emissivity in the board | substrate 1 when the diameter of the blower outlet 33a is set to 0.5 mm, 1.0 mm, and 1.5.

As a result of confirming by single-layer SEM observation, when a diameter of the jet port 33a is 0.5 mm, the growth of the carbon nanowall in the substrate vertical direction at each of the observation points A and B is not seen, and the jet port 33a is No significant difference is observed in the growth of the carbon nanowalls in the vertical direction of the substrate at the observation points A and B when the diameter is 1.0 mm, and at each of the observation points A and B when the diameter of the jet port 33a is 1.5 mm. No significant difference was observed in the growth of the substrate vertical direction of the carbon nanowalls. However, as shown to (a)-(c) of FIG. 10, when the ejection opening diameter is 0.5 mm (phi 0.5), 1.0 mm (phi 1.0), and 1.5 mm (phi 1.5) ) Shows that the growth in the vertical direction of the substrate of the carbon nanowall in the case of φ 1.0 and φ 1.5 is greater than that in the case of φ 0.5 when comparing the single-layer SEM image at the observation point A.

As is apparent from Fig. 11, the emissivity change of the substrate is almost unchanged at? 0.5 and? 1.0, and reaches plateau after 1 hour and 30 minutes, but? 1.5 is accompanied by growth of carbon nanowalls. Increasing emissivity tends to slow down. This increase in emissivity depends on the density of the graphite components that make up the carbon nanowalls on the substrate surface.

It is also known that the growth of the carbon nanowall is faster in the vertical direction of the substrate as the amount of the active species that is perpendicular to the substrate 1 increases. At φ0.5, the emissivity is fast and reaches the plate. Since the height of the carbon nanowall is lower than that of φ1.0 and φ1.5, it is considered that the ratio of the growth rate in the transverse direction is larger than that of φ1.0 and φ1.5. do. This is because the flow rate of the active species formed by the plasma at φ 0.5 is larger in the lateral velocity component and the rate of ejection of the methane gas is too fast. It suggests that it is a bit distracted.

In the case of φ 1.5, the height in the vertical direction of the substrate of the carbon nanowall at the growth time of 2 hours is not the same as the height in the vertical direction of the substrate of the carbon nanowall of φ0.5 and φ1.0 at the deposition time of 2 hours. Although unchanged, the speed until the emissivity reaches the plate is slow compared to the other two cases, and the growth in the vertical direction of the substrate in the carbon nanowall is approximately equal to φ 1.0, so that the growth rate component in the vertical direction of the substrate is φ1. Although it is about the same as 0, the deposition rate of the whole graphite component is slow compared with (phi) 0.5 and (phi) 1.0, and it suggests that the growth rate of the carbon nanowall lateral direction is slowed by that much. This is less likely to disturb the convection of the reaction gas due to the slower ejection rate of the reaction gas, but is considered to be because the amount of the reaction gas reaching the center of the plasma is smaller than that of? 0.5 and? 1.0.

In other words, in the viewpoint A, the carbon nanowalls formed at φ0.5 have a higher density of carbon nanowalls per unit area of the substrate than the carbon nanowalls formed at φ1.5, but the growth in the vertical direction of the substrate is slow. On the other hand, the carbon nanowalls formed at φ1.5 have faster growth in the vertical direction of the substrate than the carbon nanowalls formed at φ0.5, but are slow until the density of the carbon nanowalls per unit area of the substrate is sufficiently high. However, the carbon nanowalls formed at φ1.5 grow to a sufficient density after 2 hours of deposition.

For this reason, in the case of the present embodiment, for uniform growth of the carbon nanowall, it is preferable that the moving speed of the reaction gas immediately after being ejected from the ring nozzle 33 is about 125 cm / s (nozzle of φ 1.0), and slightly Although it is inferior in uniformity, it is preferable that the moving speed of the reaction gas is about 55 cm / s (nozzle of φ 1.5) to about 125 cm / s (nozzle of phi 1.0) as long as good electron emission characteristics are obtained. .

The above-described direct current plasma CVD apparatus of this embodiment obtains the same effects as those of the first embodiment, and also has the advantages shown in the following [7].

[7] In CVD, it is generally known that the concentration of the reaction gas to the matrix gas affects the film quality, but only by introducing a mixed gas in which the reaction gas and the matrix gas are mixed at a predetermined concentration, and by naturally occurring convection. In the method of conveying the mixed gas to the substrate, a portion of the newly introduced mixed gas is discharged from the exhaust port 20 before the substrate 1 sufficiently reaches the substrate 1 by convection, so that the concentration of the reaction gas on the substrate 1 is introduced. It may be lighter than the concentration in the mixed gas. When the concentration of the reaction gas in the mixed gas is increased to compensate for this, deposition of the reaction gas on the cathode 13 and the cathode support 14 supporting the same tends to occur, which causes the plasma to move to arc discharge or flame discharge. It causes. On the other hand, the direct current plasma CVD apparatus of this embodiment introduces the matrix gas and the reaction gas independently, makes the ejection position of the reaction gas relatively high with respect to the substrate 1, and the ejection position of the matrix gas at a position higher than that. Since it is possible to control the flow of the reaction gas toward the substrate 1 by the down force of the matrix gas, it is possible to reduce the amount of the reaction gas discharged unnecessarily. In addition, since the ejection position of the matrix gas was above the cathode 13 or the cathode support 14 supporting the same, and the ejection position of the reaction gas was below the lower surface of the cathode 13, the matrix gas was discharged to the exhaust pipe. Since downforce is given until it reaches (20), it is suppressed that the reaction gas flows back toward the cathode 13 against the direction of the flow of the matrix gas, and the cathode 13 or the cathode support 14 supporting it is suppressed. It is possible to prevent the components of the reaction gas from adhering to).

[Fourth Embodiment]

12A and 12B are structural diagrams of a direct current plasma CVD apparatus according to a fourth embodiment of the present invention, and elements common to those of the direct current plasma CVD apparatus according to the third embodiment in FIG.

In this DC plasma CVD apparatus, the cathode 13 of the DC plasma CVD apparatus of FIG. 6 is changed to the cathode 35, and the voltage setting unit 21 is changed to the voltage setting unit 36.

The cathode 35 is a center electrode 35a facing the center of the anode 11a and a ring shape (Fig. 12B) surrounding the outer circumference of the center electrode 35a, and concentric with the center electrode 35a. A peripheral electrode 35b facing the peripheral portion of the anode 11a and an insulating portion 35c such as ceramic filled with no gap between the central electrode 35a and the peripheral electrode 35b are provided.

When the insulating portion 35c is not interposed between the center electrode 35a and the peripheral electrode 35b, if the distance between the center electrode 35a and the peripheral electrode 35b is not long enough, then only the substrate 1 is provided. Rather, films grown by active species are deposited on the sidewalls of the center electrode 35a and the peripheral electrode 35b facing each other. For this reason, by interposing the insulating part 35c, film is prevented from being deposited on the side wall of the center electrode 35a and the side wall of the peripheral electrode 35b which oppose each other.

The voltage setting section 36 includes a control section 36a and variable power supplies 36b and 36c.

The control part 36a is connected with the radiation thermometer 18 by the lead wire. The controller 36a controls the variable power supplies 36b and 36c, and controls the voltage or current between the anode 11a and the center electrode 35a, and the voltage or current between the anode 11a and the peripheral electrode 35b. It has the function to set each individually. The other configuration is the same as that of the direct current plasma CVD apparatus of FIG.

In the case of forming the film on the substrate 1 using the DC plasma CVD apparatus of FIG. 12, when the plasma rises, the substrate 1 is rotated at 1 rpm, and the anode 11a and the center are controlled by the voltage setting unit 36. The voltage between the cathode 35 and the anode 11a is set so that the voltage between the electrode 35a is higher than the voltage between the anode 11a and the peripheral electrode 35b. By applying such a voltage application method, a positive light column PC of plasma can be generated between the anode 11a and the center electrode 35a, and generation of an arc in the initial stage of film formation can be prevented.

In this way, after the stable positive liquor PC is formed on the upper portion of the center portion of the substrate 1 by the application of voltage or current, the voltage setting portion 36a is a voltage between the anode 11a and the center electrode 35a. Alternatively, a voltage or current is applied such that the current value is less than the voltage between the anode 11a and the peripheral electrode 35b or less than the current value, whereby the temperature between the anode 11a and the center electrode 35a is applied. The substrate 1 is formed by approximating or roughly matching the temperature between the anode 11a and the peripheral electrode 35b.

As described above, in the present embodiment, the cathode 35 is composed of the center electrode 35a and the peripheral electrode 35b, and the voltage or current value between the anode 11a and the center electrode 35a, and the anode 11a. ) And the voltage or current between the peripheral electrode 35b can be set independently. When the plasma rises, the voltage between the anode 11a and the center electrode 35a is made higher than the voltage between the anode 11a and the peripheral electrode 35b. Thereby, the positive column PC can be formed by shortening the distance of the anode 11a and the cathode 35. FIG. The voltage applied to the positive electrode 11a and the negative electrode 35 may be low, so that the frequency of occurrence of arc discharge or spark discharge can be suppressed.

In addition, with respect to the current flowing through the center electrode 35a, the current flowing through the peripheral electrode 35b is reduced so that the positive light column PC concentrated in the center of the substrate 1 is generated, and then the peripheral electrode 35b is generated. By increasing the current to be applied to the peripheral electrode 35b by increasing the power to be applied, local arc discharge occurring at the beginning of film formation can be prevented, and then the bright wine PC can be grown to the required size.

[Fifth Embodiment]

Fig. 13 is a configuration diagram showing a direct current plasma CVD apparatus according to the fifth embodiment of the present invention.

FIG. 14 is a schematic view showing a cathode, a source gas nozzle, and an exhaust pipe of the DC plasma CVD apparatus of FIG. 13 from above.

15 is a schematic cross-sectional view of the direct-current plasma CVD apparatus of FIG. 13 viewed from the side.

This DC plasma CVD apparatus is an apparatus which forms a film on the surface of the board | substrate 1 to be processed, and is equipped with the chamber 50 which is a reaction tank. The chamber 50 isolates the substrate 1 from the outside air.

In the chamber 50, a rectangular rectangular steel stage 51 is disposed, and a rectangular plate-shaped thermal conductivity is good on the upper part of the stage 51, and a high melting point, for example, a molybdenum or graphite anode 51a. This is mounted. The substrate 1 is fixed to the upper mounting surface of the anode 51a. The board | substrate 1 may be rectangular, and you may arrange | position the square board | substrate 1 to the some anode 51a.

The closed space 51b is provided in the stage 51 below the anode 51a, and the cooling member 52 is disposed in the space 51b. The cooling member 52 is provided in order to cool the board | substrate 1 as needed, and is structured so that the cooling member 52 can move up and down like an arrow by the moving mechanism which is not shown in figure. The cooling member 52 is made of a metal having high thermal conductivity such as copper, and inside thereof, a cooling medium such as cooled water or cooled calcium chloride solution is supplied from the conduit 52a to the flow path 52b in the cooling member 52. It enters and circulates so that it may be discharged | emitted from the pipeline 52c, and the whole cooling member 52 is cooled.

For this reason, when the cooling member 52 moves upwards, the upper surface 1 of the cooling member 52 abuts on the lower surface of the stage 51, and the stage 51 which abuts is the anode of the upper part ( 51a) is cooled and the anode 11a takes the structure of the board | substrate 1 away. The upper surface of the cooling member 52 is rectangular, and cools the whole longitudinal direction of the stage 51.

The cooling medium discharged from the conduit 52c is cooled by a cooling device (not shown) and circulated to be sent to the conduit 52a again.

Moreover, the space 51b provided below the anode 51a is partitioned by the stage 51, and gas is enclosed in the inside or is open | released to the atmosphere.

A rectangular plate-shaped negative electrode 53 is disposed above the positive electrode 51a. The negative electrode 53 is supported by the negative electrode support body 54, and the negative electrode 53 and the positive electrode 51 a face each other. The cathode 53 is made of molybdenum or graphite having a high melting point.

The negative electrode support body 54 is comprised from heat resistant oxides, such as quartz glass and aluminum, heat resistant nitrides, such as aluminum nitride and silicon nitride, or heat resistant carbides, such as silicon carbide.

The flow path through which the cooling medium flows may be formed inside the cathode 53. Overheating of the cathode 53 can be suppressed by the flow of the cooling medium. As a cooling medium, water, calcium chloride aqueous solution, etc. which are introduce | transduced from the exterior of the chamber 50 are preferable.

Insulators 55 for suppressing the generation of arc are arranged near the outer circumferential surface of the anode 51a. The insulator 55 is comprised with at least any one of heat resistant oxides, such as quartz glass and alumina, heat resistant nitrides, such as aluminum nitride and silicon nitride, and heat resistant carbides, such as silicon carbide.

The insulator 55 is annular and is supported at the same height as the anode 51a by the support body 56 that stands up at the bottom of the chamber 50, and surrounds the outer periphery of the anode 51a close to the inner circumference side. .

In addition, the insulator 55 suppresses the occurrence of abnormal discharge (arc discharge, spark discharge) between the cathode 53 and the anode 51a, and the cathode 53 and the cathode 53a are disposed along the outer circumferential side of the anode 51a. It is mounted toward. The insulator 55 may hide the side surface of the positive electrode 51a with respect to the negative electrode 53.

The window 57 is formed in the side surface of the chamber 50, and the observation in the chamber 50 is attained. The heat resistant glass is inserted into the window 57, and the airtightness in the chamber 50 is ensured. Outside the chamber 50, a radiation thermometer 58 is arranged which measures the temperature of the substrate 1 through, for example, the glass of the window 57.

This DC plasma CVD apparatus includes a raw material system (not shown) for introducing a raw material gas containing a reactive gas through a gas tube 59, and discharges gas from the chamber 50 through a plurality of exhaust conduits 60. And an exhaust system (not shown) for adjusting the air pressure in the chamber 50 and a voltage setting section 61.

The gas tube 59 is introduced into the chamber 50 through a hole provided in the chamber 50, and at least a part of the gas tube 59 in the reaction tank is made of an insulator such as fluororesin or silicone rubber. Between the hole and the outer circumference of the gas tube 59 is sealed with a sealing material, and the airtightness in the chamber 50 is ensured. In the chamber 50, the gas tube 59 is connected to the nozzle 62 which is a gas introduction nozzle.

The nozzle 62 has a portion 62A parallel to one long side of the anode 51a and the cathode 53, and a portion 62B parallel to the other long side of the anode 51a and the cathode 53. . The whole nozzle 62 may be annular, and the parts 62A and 62B may branch off from the connection point with the gas tube 59. The nozzle 62 is hollow so that source gas can flow. A plurality of ejection openings 62a are formed at portions 62A and 62B of the nozzle 62 at equal intervals in line symmetry with respect to the axis 53x which is the central axis along the long direction of the cathode 53 at the portions 62A and 62B. Then, the source gas is ejected horizontally from the jet port 62a toward the substrate 1 side, that is, in the inner lateral direction.

The nozzle 62 is supported by the nozzle support 63 of the insulator attached to the cathode support 54. The height at which the nozzle 62 is supported is a position below the lowermost part of the cathode support 54 (the uppermost part on the side where the cathode 53 is exposed), and between the anode 51a and the cathode 53. It is set so that it may become a position higher than the highest point of the bright wine PC which generate | occur | produces. When the nozzle 62 is supported in this range, it is easy for the source gas to enter between the cathode 53 and the anode 51a, and the temperature of the bright wine PC can be prevented from being locally cooled by the ejection of the source gas. Can be.

The interval between the portions 62A and 62B of the nozzle 62 is larger than the width (short direction) of the cathode 53, and the portions 62A and 62B of the nozzle 62 are the cathode 53 as shown in FIG. 14. It is located on the outside of both sides of the long direction of. Portions 62A and 62B are approximately equidistant from the elongated centerline of anode 51a.

The exhaust conduit 60 penetrates through the plurality of holes opened at equal intervals so as to surround the stage 51 on the bottom surface of the chamber 50. The sealing member is sealed between the hole and the outer circumference of the exhaust conduit 60.

The voltage setting unit 61 is a control device for setting a voltage or current value between the positive electrode 51a and the negative electrode 53, and includes a control unit 61a and a variable power supply 61b. The voltage setting section 61, the positive electrode 51a and the negative electrode 53 are connected by lead wires, respectively. Each lead wire passes through a hole provided in the chamber 50. The hole through which the lead wire passed is sealed with a sealing material.

The control part 61a of the voltage setting part 61 is connected by the radiation thermometer 58 and the lead wire, and is connected by the variable power supply 61b and the lead wire. When the control part 61a starts, it references the temperature of the board | substrate 1 measured by the radiation thermometer 58, and between the anode 51a and the cathode 53 so that the temperature of the board | substrate 1 may become a predetermined value. Adjust the voltage or current value.

Next, a film forming process of forming a film on the substrate 1 using the direct current plasma CVD apparatus of FIG. 13 will be described.

In this film forming process, an electron-emitting film made of carbon nanowalls is formed on the surface of the substrate 1.

In the film forming process, first, for example, the nickel plate is cut out as the substrate 1, and degreasing / ultrasound washing is sufficiently performed with ethanol or acetone.

This substrate 1 is mounted on the anode 51a.

When the mounting of the substrate 1 is completed, the chamber 50 is then depressurized using an exhaust system, and thereafter, a compound containing carbon in the composition of hydrogen gas and methane from the gas tube 59 as a source gas. The reaction gas (carbon-containing compound) of is sent. The source gas is ejected from the ejection opening 62a of the nozzle 62.

At the time of film-forming of carbon nanowall, film formation of predetermined time is performed at 900 degreeC-1100 degreeC in the temperature of the location where the carbon nanowall of the board | substrate 1 is formed. This temperature is measured by the radiation thermometer 58. At this time, the cooling member 52 is sufficiently separated from the anode 51a so as not to affect the temperature of the anode 51a. The radiation thermometer 58 is set to subtract the plasma radiation of the direct-current plasma CVD apparatus to obtain a temperature from only heat radiation on the surface of the substrate 1 side.

In the process of forming the carbon nanowall, for example, the film quality of the electron-emitting film is changed, and when the diamond layer including a plurality of diamond fine particles is laminated on the carbon nanowall, the cooling member 52 is raised on the anode 51a. Make contact. Thereby, the temperature of the board | substrate 1 can be cooled dramatically, and a diamond layer can be laminated | stacked. With the growth of the diamond layer, the carbon of the sp ² bond in which the core is piled up grows from the gap of the diamond layer in which a part of carbon nanowall is deformed, and unlike this nanotube. This rod-shaped carbon extends so as to protrude from the surface of the diamond layer, and is structurally easy to concentrate an electric field and becomes a site for emitting electrons.

At the end of film formation, the voltage between the anode 51a and the cathode 53 stops the application, the supply of the source gas is stopped, and the nitrogen gas is supplied into the chamber 50 as a purge gas to supply the chamber 50. The inside of the inside) is placed in a nitrogen atmosphere, and the substrate 1 is taken out in the state of returning to normal temperature.

In the DC plasma CVD apparatus according to the present embodiment described above, the same effects as in [1] to [6] of the first embodiment can be obtained, and also have advantages shown in the following [8] and [9].

[8] When the film is to be formed on the large substrate 1, it is necessary to increase the area (outer diameter) of the anode 11a and the cathode 13 in the DC plasma CVD apparatus of the first embodiment. However, when the outer diameters of the positive electrode 11a and the negative electrode 13 are increased, the reaction gas supplied to the center of the positive electrode 11a may be insufficient, or there may be a temperature difference that cannot be ignored between the outer peripheral side and the center portion. Therefore, there was a risk of unevenness in film formation.

In contrast, in the DC plasma CVD apparatus according to the present embodiment described above, the anodes 51a and the cathode 53 have a rectangular shape, and portions 62A and 62B of the nozzles 62 shifted in the long direction are arranged. This makes it possible to supply the raw material gas which does not fluctuate in the long direction, and to suppress the unevenness of film formation in the long direction. Therefore, if the length of the short direction of the anode 51a and the cathode 53 is set appropriately, the film-forming which the nonuniformity was suppressed with respect to the board | substrate 1 of a large area is possible.

[9] Since the anode 51a and the cathode 53 are rectangular, the square substrates 1 can be arranged in the long direction of the anode 51a and the cathode 53, and the plurality of substrates 1 can be disposed at one time. It is possible to form a film at the same time, and is suitable for mass production. In this case, since the plurality of substrates 1 are formed by the same robot, if the required number is formed at the same time, it is not necessary to take into account the nonuniformity between the robots.

[Sixth Embodiment]

FIG. 16A is a configuration diagram of a DC plasma CVD apparatus according to a sixth embodiment of the present invention, and FIG. 16B is a plan view of the cathode viewed from below.

FIG. 17 is a view showing a cathode, a source gas nozzle, and an exhaust pipe of the DC plasma CVD apparatus of FIG. 16A from above.

18 is a sectional side view of the direct-current plasma CVD apparatus of FIG. 16A.

In this DC plasma CVD apparatus, the cathode 53 of the DC plasma CVD apparatus of the fifth embodiment shown in FIG. 13 is changed to the cathode 65, and the voltage setting unit 61 is changed to the voltage setting unit 66. .

The cathode 65 is a central electrode 65a facing the center of the anode 51a and an annular shape (Fig. 16B) surrounding the outer circumference of the center electrode 65a, and the peripheral electrode 65b facing the peripheral portion of the anode 51a. ) And an insulating portion 65c such as ceramic, which is filled between the center electrode 65a and the peripheral electrode 65b without a gap.

When the insulating portion 65c is not interposed between the center electrode 65a and the peripheral electrode 65b, if the distance between the center electrode 65a and the peripheral electrode 65b is not long enough, then only the substrate 1 is provided. Rather, films grown by active species are deposited on the sidewalls of the center electrode 65a and the peripheral electrode 65b facing each other. For this reason, the carbon film is prevented from being deposited on the side wall of the center electrode 65a and the side wall of the peripheral electrode 65b which face each other by interposing the insulating portion 65c.

The voltage setting section 66 includes a control section 66a and variable power supplies 66b and 66c.

The control part 66a is connected with the radiation thermometer 58 by the lead wire. The controller 66a controls the variable power sources 66b and 66c and controls the voltage or current between the anode 51a and the center electrode 65a and the voltage or current between the anode 51a and the peripheral electrode 65b. It has the function to set each individually. The other configuration is the same as that of the direct current plasma CVD apparatus of FIG.

In the case where the film is formed on the substrate 1 using the DC plasma CVD apparatus of FIG. 16, the potential difference between the anode 51a and the center electrode 65a is controlled by the voltage setting unit 66 at the time of the plasma rise. The voltage between the cathode 65 and the anode 51a is set so as to be larger than the potential difference between the anode 51a and the peripheral electrode 65b. By applying such a voltage application method, the positive beam PC of plasma can be generated between the anode 51a and the center electrode 65a, and the generation of an arc in the initial stage of film formation can be prevented.

By applying a voltage or a current in this manner, a stable positive liquor PC is formed on the upper portion of the center portion of the substrate 1. Thereafter, the controller 66a controls the voltage or current such that the voltage or current value between the anode 51a and the center electrode 65a is less than the voltage or current value between the anode 51a and the peripheral electrode 65b. Is applied to form a film on the substrate 1 by approximating or roughly matching the temperature between the anode 51a and the center electrode 65a and the temperature between the anode 51a and the peripheral electrode 65b. Is carried out.

As described above, in the present embodiment, the cathode 65 is composed of the center electrode 65a and the peripheral electrode 65b, and the voltage or current value between the anode 51a and the center electrode 65a, and the anode 51a. ) And the voltage or current between the peripheral electrode 65b can be set independently. When the plasma rises, the voltage between the anode 51a and the center electrode 65a is made higher than the voltage between the anode 51a and the peripheral electrode 65b. As a result, the distance between the positive electrode 51a and the negative electrode 65 can be shortened to form a positive wine column PC. The voltage applied to the positive electrode 51a and the negative electrode 65 may be low, and the occurrence frequency of arc discharge or spark discharge can be suppressed.

In addition, with respect to the current flowing through the center electrode 65a, the current flowing through the peripheral electrode 65b is reduced so that a positive light column PC focused on the long center of the substrate 1 is generated, and then the peripheral electrode 65b. By increasing the power added to), increasing the current flowing through the peripheral electrode 65b, local arc discharge occurring at the beginning of film formation can be prevented, and then the bright wine PC can be grown to the required size.

[Seventh Embodiment]

FIG. 19 is a configuration diagram showing the direct-current plasma CVD apparatus according to the seventh embodiment of the present invention, in which elements common to those in FIG. 13 are assigned the same reference numerals.

20 is a view showing a cathode, a reaction gas nozzle and a matrix gas nozzle, and an exhaust pipe of the DC plasma CVD apparatus of FIG. 19 from above.

FIG. 21 is a side cross-sectional view of the DC plasma CVD apparatus of FIG. 19.

This DC plasma CVD apparatus is an apparatus which forms a film on the surface of the board | substrate 1 to be processed, and is equipped with the chamber 70 which is a reaction tank. The chamber 70 isolates the substrate 1 from the outside air.

In the chamber 70, a forged rectangular stage 51 is disposed, and a rectangular plate-shaped thermal conductivity is good on the upper stage 51, and a high melting point, for example, molybdenum or graphite anode 51a is formed. It is mounted. The substrate 1 is fixed to the upper mounting surface of the anode 51a. The board | substrate 1 may be rectangular, and you may arrange | position the square board | substrate 1 to the some anode 51a.

The closed space 51b is provided in the stage 51 below the anode 51a, and the cooling member 52 is disposed in the space 51b. The cooling member 52 is provided in order to cool the board | substrate 1 as needed, and is structured so that the cooling member 52 can move up and down like an arrow by the moving mechanism which is not shown in figure. The cooling member 52 is made of a metal having high thermal conductivity such as copper, and inside the cooling medium such as cooled water or cooled calcium chloride aqueous solution is transferred from the conduit 52a to the flow path 52b in the cooling member 52. It enters and circulates so that it may be discharged | emitted from the conduit 52c, and the whole cooling member 52 is cooled.

For this reason, when the cooling member 52 moves upwards, the upper surface 1 of the cooling member 52 abuts on the lower surface of the stage 51, and the stage 51 which abuts is the anode of the upper part ( The structure 51a is cooled, and the anode 51a takes the heat of the board | substrate 1 into consideration. The upper surface of the cooling member 52 is rectangular, and cools the whole longitudinal direction of the stage 51.

The cooling medium discharged from the conduit 52c is cooled by a cooling device (not shown), and is circulated to be sent to the conduit 52a again.

Moreover, the space 51b provided below the anode 51a is partitioned by the stage 51, and gas is enclosed in the inside or is open | released to the atmosphere.

A rectangular plate-shaped negative electrode 53 is disposed above the positive electrode 51a. The negative electrode 53 is supported by the negative electrode support body 54, and the negative electrode 53 and the positive electrode 51 a face each other. The cathode 53 is made of molybdenum or graphite having a high melting point.

The negative electrode support body 54 is comprised from heat resistant oxides, such as quartz glass and aluminum, heat resistant nitrides, such as aluminum nitride and silicon nitride, or heat resistant carbides, such as silicon carbide.

The flow path through which the cooling medium flows may be formed inside the cathode 53. Overheating of the cathode 53 can be suppressed by the flow of the cooling medium. As a cooling medium, water, calcium chloride aqueous solution, etc. which are introduce | transduced from the exterior of the chamber 70 are preferable.

Insulators 55 for suppressing the generation of arc are arranged near the outer circumferential surface of the anode 51a. The insulator 55 is comprised with at least any one of heat resistant oxides, such as quartz glass and alumina, heat resistant nitrides, such as aluminum nitride and silicon nitride, and heat resistant carbides, such as silicon carbide.

The insulator 55 is annular and is supported at the same height as the anode 51a by the support body 56 that stands up at the bottom of the chamber 70, and surrounds the outer periphery of the anode 51a close to the inner circumference side. .

The insulator 55 suppresses the occurrence of abnormal discharge (arc discharge, flame discharge) between the cathode 53 and the anode 51a, and the cathode 53 and the outer circumferential side of the anode 51a. It is mounted oppositely. The insulator 55 may hide the side surface of the positive electrode 51a with respect to the negative electrode 53.

The window 57 is formed in the side surface of the chamber 70, and the observation in the chamber 70 is possible. The heat resistant glass is inserted in the window 57, and the airtightness in the chamber 70 is ensured. Outside the chamber 70, a radiation thermometer 58 is arranged which measures the temperature of the substrate 1 through the glass of the window 57, for example.

The DC plasma CVD apparatus includes a reaction gas system (not shown) for introducing a reaction gas through the gas tube 71, a raw material system (not shown) for introducing the matrix gas through the gas tube 72, and a chamber 70. And an exhaust system (not shown) for adjusting the air pressure in the chamber 70 by discharging the gas from the inside of the chamber through the plurality of exhaust pipe lines 60, and a voltage setting unit 61.

The gas tube 71 is introduced into the chamber 70 through a hole provided in the chamber 70, and is formed of an insulator such as fluororesin or silicone rubber in at least part of the reaction tank. Between the hole and the outer periphery of the gas tube 71 is sealed with a sealing material, and the airtightness in the chamber 70 is ensured. In the chamber 70, the gas tube 71 is connected to the nozzle 73 which is a gas introduction nozzle.

The nozzle 73 has a portion 73A parallel to one long side of the anode 51a and the cathode 53, and a portion 73B parallel to the other long side of the anode 51a and the cathode 53. . The whole nozzle 73 may be annular, and the parts 73A and 73B may branch off from the connection point with the gas tube 71. The nozzle 73 is hollow so that source gas can flow. A plurality of ejection openings 73a are formed at portions 73A and 73B of the nozzle 73 at equal intervals in line symmetry at the portions 73A and 73B, and the source gas is horizontal from the ejection opening 73a toward the substrate 1 side. , That is, it is ejected in the inner transverse direction.

The nozzle 73 is supported by the nozzle support 63 of the insulator attached to the cathode support 54. The height at which the nozzle 73 is supported is the position below the lowermost part of the cathode support 54 (the uppermost part on the side where the cathode 53 is exposed), and between the anode 51a and the cathode 53. It is set so that it may become a position higher than the highest point of the positive beam PC which arises at the time. When the nozzle 73 is supported in this range, it is easy for the source gas to enter between the cathode 53 and the anode 51a, and it is possible to prevent the temperature of the bright wine PC from being locally cooled by the ejection of the source gas. Can be.

The distance between the portions 73A and 73B of the nozzle 73 is larger than the width (short direction) of the cathode 53, and the portions 73A and 73B of the nozzle 73 are the cathodes 53 as shown in FIG. 20. It is located on the outside of both sides of the long direction of. The portions 73A and 73B are approximately equidistant from the long center line of the anode 51a.

The exhaust conduit 60 penetrates through the plurality of holes opened at equal intervals so as to surround the stage 71 on the bottom surface of the chamber 70. The sealing member is sealed between the hole and the outer circumference of the exhaust conduit 60.

The voltage setting unit 61 is a control device for setting a voltage or current value between the positive electrode 51a and the negative electrode 53, and includes a control unit 61a and a variable power supply 61b. The voltage setting section 61, the positive electrode 51a and the negative electrode 53 are connected by lead wires, respectively. Each lead wire passes through a hole provided in the chamber 70. The hole of the chamber 70 through which the lead wire passed is sealed with the sealing material.

The control part 61a of the voltage setting part 61 is connected by the radiation thermometer 58 and the lead wire, and is connected by the variable power supply 61b and the lead wire. When the control part 61a starts, the radiation thermometer 58 refers to the temperature of the measured board | substrate 1, and between the anode 51a and the cathode 53 so that the temperature of the board | substrate 1 may become a predetermined value. Adjust the voltage or current value.

The gas tube 72 consists of an insulator and passes through the hole provided in the chamber 70. The sealing member is sealed between the hole and the outer circumference of the gas tube 72 to secure the airtightness in the chamber 70. In the chamber 70, the gas tube 72 is connected to the gas shower nozzle 74 for matrix gas.

The gas shower nozzle 74 has a length substantially the same as that of the cathode 53, and is disposed above the cathode support 54 supporting the cathode 53 and at a height above the nozzle 73, and the cathode 53. It is arranged so as to be parallel and linearly symmetrical about the axis 53x which is the central axis along the long direction of, and blows the matrix gas downward into the shower shape.

The basic operation | movement at the time of forming into a film using the DC plasma CVD apparatus of this embodiment is the same as the case of using the DC plasma CVD apparatus of 5th Embodiment. However, in the DC plasma CVD apparatus of the present embodiment, the matrix gas and the reaction gas are introduced independently, the reaction gas is ejected from the nozzle 73 inward and horizontal direction, and the matrix gas is lowered from the gas shower nozzle 74. Ejected in the direction. The matrix gas changes the vector of the flow of the reaction gas ejected in the transverse direction and flows obliquely toward the substrate 1 toward the substrate 1.

The above-described direct current plasma CVD apparatus of this embodiment obtains the same effects as those of the fifth embodiment, and also has the advantages shown in the following [10].

[10] In CVD, it is generally known that the concentration of the reaction gas with respect to the matrix gas affects the film quality, but only by introducing a mixed gas in which the reaction gas and the matrix gas are mixed at a predetermined concentration, and by naturally occurring convection. In the method of conveying the mixed gas to the substrate, the conduit for exhaust gas before the mixed gas sufficiently reaches the substrate 1 to the extent that it can be sufficiently formed on the substrate 1 by the newly introduced mixed gas by convection ( 60), it is possible to consume the reaction gas unnecessarily. When the concentration of the reaction gas in the mixed gas is increased to compensate for this, deposition of the reaction gas easily occurs on the cathode 53 or the insulating cathode support 54 supporting it, which causes the plasma to be arc discharged or flame discharged. It causes the transition. In contrast, the direct current plasma CVD apparatus of this embodiment introduces the matrix gas and the reaction gas independently, makes the ejection position of the reaction gas relatively high with respect to the substrate 1, and the ejection position of the matrix gas at a position higher than that. Since it is possible to control the flow of the reaction gas toward the substrate 1 by the downforce of the matrix gas, the ejection position of the matrix gas is directed to the cathode 53 or the insulating cathode support 54 supporting it. In addition, since the ejection position of the reaction gas is lower than the lower surface of the cathode 53, downforce is applied until the matrix gas reaches the exhaust conduit 60, so that the reaction gas is The backflow toward the cathode 53 is suppressed against the direction, and the component of the reaction gas adheres to the cathode 53 or the insulating cathode support 54 supporting it. Can be prevented.

[Eighth Embodiment]

22A and 22B are structural diagrams of a direct-current plasma CVD apparatus according to an eighth embodiment of the present invention, in which elements common to those in FIG. 19 are assigned the same reference numerals.

FIG. 23 is a view showing a cathode, a reaction gas nozzle, a matrix gas nozzle, and an exhaust pipe of the DC plasma CVD apparatus of FIG. 22A from above.

FIG. 24 is a side cross-sectional view of the direct-current plasma CVD apparatus of FIG. 22A.

In this DC plasma CVD apparatus, the cathode 53 of the DC plasma CVD apparatus of the seventh embodiment shown in FIG. 19 is changed to the cathode 75, and the voltage setting unit 61 is changed to the voltage setting unit 76. .

The cathode 75 is a center electrode 75a facing the center of the anode 51a and an annular shape (Fig. 22B) surrounding the outer circumference of the center electrode 75a, and the peripheral electrode 75b facing the periphery of the anode 51a. ) And an insulating portion 75c such as ceramic, which is filled between the center electrode 75a and the peripheral electrode 75b without a gap.

When the insulating portion 75c is not interposed between the center electrode 75a and the peripheral electrode 75b, if the distance between the center electrode 75a and the peripheral electrode 75b is not long enough, then only the substrate 1 is provided. Rather, films grown by active species are deposited on the sidewalls of the center electrode 75a and the peripheral electrode 75b facing each other. For this reason, the carbon film is prevented from being deposited on the side wall of the center electrode 75a and the side wall of the peripheral electrode 75b which face each other by interposing the insulating portion 75c.

The voltage setting section 76 includes a control section 76a and variable power supplies 76b and 76c.

The control unit 76a is connected to the radiation thermometer 58 by a lead wire. The controller 76a controls the variable power supplies 76b and 76c, and controls the voltage or current between the anode 51a and the center electrode 75a, and the voltage or current between the anode 51a and the peripheral electrode 75b. It has the function to set each individually. The other configuration is the same as that of the direct current plasma CVD apparatus of FIG.

In the case where the film is formed on the substrate 1 using the DC plasma CVD apparatus of FIG. 22, when the plasma rises, the voltage between the anode 51a and the center electrode 75a is controlled by the control of the voltage setting unit 76. The voltage between the cathode 75 and the anode 51a is set to be higher than the voltage between the anode 51a and the peripheral electrode 75b. By applying such a voltage application method, the positive beam PC of plasma can be generated between the anode 51a and the center electrode 75a, and generation of an arc in the initial stage of film formation can be prevented.

By applying a voltage or a current in this way, a stable positive liquor PC is formed in the upper part of the center part of the board | substrate 1. As shown in FIG. Thereafter, the controller 76a controls the voltage or current such that the voltage or current value between the anode 51a and the center electrode 75a is less than the voltage or current value between the anode 51a and the peripheral electrode 75b. Is applied to form a film on the substrate 1 by approximating or roughly matching the temperature between the anode 51a and the center electrode 75a and the temperature between the anode 51a and the peripheral electrode 75b. Is carried out.

As described above, in the present embodiment, the cathode 75 is composed of the center electrode 75a and the peripheral electrode 75b, and the voltage or current value between the anode 51a and the center electrode 75a, and the anode 51a. ) And the voltage or current between the peripheral electrode 75b can be set independently. When the plasma rises, the voltage between the anode 51a and the center electrode 75a is made higher than the voltage between the anode 51a and the peripheral electrode 75b. Thereby, the positive column PC can be formed by shortening the distance between the anode 51a and the cathode 75. FIG. The voltage applied to the positive electrode 51a and the negative electrode 75 may be low, so that the frequency of occurrence of arc discharge or spark discharge can be suppressed.

In addition, the amount of current flowing through the peripheral electrode 75b is reduced with respect to the current flowing through the center electrode 75a, so that a positive light column PC concentrated at the long center of the substrate 1 is generated. Thereafter, the peripheral electrode 75b is used. By increasing the power added to the peripheral electrode 75b to increase the current, the local arc discharge occurring at the beginning of film formation can be prevented, and then the bright wine PC can be grown to the required size.

In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible. Examples of such modifications include the following.

[a] The configuration of the cathodes 27 and 35 composed of a plurality of electrodes can be appropriately changed depending on the size of the substrate 1 and the anode 11a serving as the processing object. For example, the cathode 90 of FIG. 25 is composed of a central electrode 90a and a plurality of peripheral electrodes 90b. In this case, the voltage or current value between the anode 11a may be set individually for each of the plurality of peripheral electrodes 90b. An insulating part 90c made of ceramic is filled between the center electrode 90a and the peripheral electrode 90b. The cathodes 91 and 92 shown in FIGS. 26 and 27 have a plurality of peripheral electrodes 91b and 92b of the same size as the center electrodes 91a and 92a. In each of the electrodes 91 and 92, insulating portions 91c and 92c made of ceramic are filled between the peripheral electrodes 91b and 92b and the center electrodes 91a and 92a.

[b] The configurations of the cathodes 27 and 35 were arranged concentrically with the center electrodes 27a and 35a and the peripheral electrodes 27b and 37b. However, as shown in the cathode 93 shown in FIG. A ring-shaped center electrode 93a, a ring-shaped first peripheral electrode 93b surrounding the outer circumference of the center electrode 93a, and a ring-shaped space surrounding the outer circumference of the first peripheral electrode 93b The second peripheral electrode 93c may be provided.

[c] The cooling member 12 can also be modified.

FIG. 29A is a top view showing another modified example of the cooling member 12 of the DC plasma CVD apparatus, and FIG. 29B is a cooling member 12 along the line AA of FIG. 29A. It is a schematic cross section of. FIG. 30A is a top view of the cooling member 12 of FIG. 29, and FIG. 30B shows an operation during cooling of the cooling member 12 along the line BB of FIG. 30A. It is a schematic cross section. In the plasma CVD apparatuses shown in FIGS. 29A and 29B, the cooling members 12 are provided with conduits 12a, 12b, and 12c through which the cooling medium supplied from the cooling apparatus 99 passes. Moreover, the groove | channel 12y which communicates from the vent 12x to the side surface 12z of the cooling member 12 is formed in the upper surface 12w of the cooling member 12. As shown in FIG. For this reason, as shown to FIG. 30 (b), even if the upper surface 12w of the cooling member 12 abuts on the stage 11, cold gas will flow by the flow path which arose in the clearance gap between the groove 12y and the stage. By moving as shown by the arrow, it can be efficiently aerated and cooled. Moreover, helium gas from which the discharge flow rate was adjusted by the flow volume control part 95 is sent from the helium gas sealing part 94 to the three-way valve 98. FIG. The nitrogen gas in which the discharge flow rate was adjusted by the flow rate adjusting part 97 from the nitrogen gas encapsulation part 96 is sent out to the three-way valve 98. When the three-way valve 98 is opened, the nitrogen gas whose discharge flow rate is adjusted by the flow rate adjusting part 97 from the cooled helium gas and the cooled nitrogen gas encapsulation part 96 is sent to the three-way valve 98. When the three-way valve 98 is opened, the cooled helium gas and the cooled nitrogen gas may be blown out to the contact surface of the stage 11 through the vent 12x to cool the substrate 1.

[Ninth Embodiment]

31 is a configuration diagram showing an outline of a plasma CVD apparatus according to a ninth embodiment of the present invention.

This DC plasma CVD apparatus is an apparatus which forms a film on the surface of the board | substrate 101 to be processed, and has the chamber 110 which is a reaction tank. The chamber 110 blocks the substrate 101 from the outside air.

In the chamber 110, a columnar forced stage 111 is disposed, and a disk-shaped anode 112 is mounted on the electrode mounting surface 111a on the upper portion of the stage 111. For example, a rectangular substrate 101 is mounted on the substrate mounting surface 112a on the upper side of the anode 112. The anode 112 is formed of graphite, and the arithmetic mean roughness Ra of the surface thereof is about 5 µm.

The outer circumferential surface of the anode 112 is surrounded by a ring 114 made of an insulator such as quartz glass. The stage 111, the anode 112, and the ring 114 are set to rotate about the axis 111x.

In the stage 111 below the anode 112, a closed cylindrical space 111b is provided, and a portion of the electrode mounting surface 111a of the stage 111 has a plate shape.

The columnar cooling member 113 is disposed in the space 111b of the stage 111. The cooling member 113 is provided in order to cool the board | substrate 101 as needed, and is formed with the metal of high thermal conductivity, such as copper. The cooling member 113 is structured to move up and down like an arrow by a moving mechanism (not shown).

The upper surface of the cooling member 113 is an opposing surface 113 opposite to the surface (hereinafter referred to as the rear surface) 111c on the side opposite to the electrode mounting surface 111a of the stage 111, and the outer diameter is It is large. By moving the cooling member 113 upward, the opposing surface 113a opposes to approach or abut the back surface 111c of the stage 111.

Inside the cooling member 113, a flow passage 113b for flowing a cooling medium such as cooled water or an aqueous calcium chloride solution is formed. The flow path 113b passes through the vicinity of the opposing surface 113a from the side surface of the cooling member 113, and reaches the side surface of the cooling member 113 again. The flow passage 113b is connected to the cooler 115 through the conduits 113c and 113d, and the cooling medium is cooled by the cooler 115 to circulate between the flow passage 113b and the cooler 115.

The vent 113e is opened in the center of the opposing surface 113a of the cooling member 113. The vent 113e penetrates through the lower side of the cooling member 113. On the lower side of the cooling member 113, the air vent 113e is connected to the conduit 116. The pipeline 116 is connected to the cylinder 119 via a valve 117 and a flow regulator 118. The cylinder 119 is filled with helium gas or nitrogen gas as a cooling gas. The cooling gas is filled in the space 111b but is not filled in the substrate mounting surface 112a side of the anode 112.

Thus, the cooling member 113 is equipped with not only the mechanism which cools the stage 111 with a cooling medium, but also the mechanism which cools the stage 111 by blowing out cooling gas to the stage 111 from the vent 113e. . Therefore, in the case where the anode 112 and the substrate 101 are cooled, a method in which the opposing surface 113a partially or entirely contacts the back surface 111c of the stage 111 or the opposing surface 113a is the back surface 111c. ) And a method of cooling the stage 111 by blowing a cooling gas to the stage 111, or both.

The cathode 120 is supported so as to face the substrate mounting surface 112a of the anode 112. A power source 121 for applying a voltage for generating a plasma is connected between the cathode 120 and the anode 112.

At a position higher than the cathode 120 of the chamber 110, a gas introduction pipe 122 for introducing a source gas supplied from a source gas system (not shown) into the chamber 110 is provided. At the bottom of the chamber 110, a gas exhaust pipe 123 for discharging raw material gas is installed.

The gas introduction pipe 122 and the gas exhaust pipe 123 pass through holes provided in the chamber 110, respectively, and are sealed between the holes and the outer circumference of the gas introduction pipe 122 and the gas exhaust pipe 123 with a sealing material. The airtightness in the chamber 110 is ensured. The gas exhaust pipe 123 is connected with an exhaust system (not shown) for discharging the source gas from the gas exhaust pipe 123 to adjust the air pressure in the chamber 110.

The window 125 for observing the inside of the chamber 110 may be formed on the side surface of the chamber 110. In this case, heat resistant glass is inserted into the window 125, and the airtightness in the chamber 110 is ensured. Outside the chamber 110, a spectroradiometer is arranged for measuring the temperature of the substrate 101 through the heat-resistant glass of the window 125.

In the case where film formation is performed on the substrate 101 using this DC plasma CVD apparatus, the substrate 101 is first mounted on the substrate mounting surface 112a of the anode 112. When the mounting of the substrate 101 is completed, the chamber 110 is then decompressed using an exhaust system, and then source gas is introduced into the chamber 110 from the gas introduction pipe 122. The source gas is mixed at a predetermined ratio with a reaction gas such as methane, which is a material for film formation, and a matrix gas (carrier gas), such as hydrogen, that is not, a film material for film formation. For example, when a carbon film such as graphite or diamond fine particles is formed on the substrate 101, the reaction gas is a gas of a compound containing carbon.

The introduction amount and the exhaust amount of the source gas are adjusted, and the air pressure in the chamber 110 is set so that the deviation from the predetermined value or the predetermined value falls within the allowable range. The substrate 111 and the anode 112 are rotated by rotating the stage 111 at, for example, 10 rpm. In this state, a DC voltage is applied between the anode 112 and the cathode 120 to generate a plasma. When plasma is generated, active species are generated from the reaction gas by the plasma, and film formation on the substrate 101 is started. By rotating the substrate 101 and the anode 112, the temperature nonuniformity due to the position of the substrate 101 becomes small, and the nonuniformity of film formation on the substrate 101 is prevented.

In order to suppress the temperature rise of the substrate 101 due to the film formation and to secure desired film quality, or to change the film quality by changing the temperature of the substrate 101 during the film formation, a cooling mechanism assembled to the cooling member 113 is appropriately used. Select and use. That is, while the cooling medium cooled by the cooler 115 flows to the flow path 113b of the cooling member 113, the opposing surface 113a may contact the back surface 111c, and the opposing surface 113a may be the back surface 111c. ) And the cooling gas may be blown out on the back surface 111c, and a part of the opposing surface 113a is brought into contact with the back surface 111c while the cooling medium flows through the flow path 113b. You may flush.

Since the surface temperature of the substrate 101 can be measured by the spectroradiometer 126, the cooling timing of the substrate 101, the anode 112 and the cathode (in accordance with the surface temperature of the substrate 101 by plasma). The voltage applied between 120 can be controlled.

When a predetermined time elapses from the start of film formation, and when the film formation is in the end stage, the application of the voltage between the anode 112 and the cathode 120 is stopped, and the supply of source gas is subsequently stopped, and the purge gas is stopped. As a result, nitrogen gas is supplied into the chamber 110 to return to normal pressure, and then the substrate 101 is taken out.

Next, the advantages of this DC plasma CVD apparatus will be described.

When film formation is performed on the substrate 101, the substrate 101, the anode 112, and the cathode 120 are heated by being exposed to a plasma generated between the anode 112 and the cathode 120. Some of the energy added to the substrate 101 is transferred to the chamber 110 by heat radiation, but most of the energy is transferred from the substrate 101 through the anode 112 and the stage 111, and also through the stage 111. The temperature of the substrate 101 is kept constant by balancing the amount of heat transmitted and the amount of heat transmitted and the amount of heat transmitted to 113.

Here, film formation was performed in the case where the anode 112 was made of graphite (hereinafter, referred to as a graphite electrode), and in the case of being made of molybdenum (hereinafter, referred to as a molybdenum electrode), and the comparison was performed. .

In the film forming conditions, for both the graphite electrode and the molybdenum electrode, the source pressure having the flow rate of methane of the reaction gas of 50 sccm and the flow rate of hydrogen of the matrix gas of 500 sccm was introduced into the chamber 110, and the exhaust pressure was adjusted to control the overall pressure. Was maintained at 999.32 Pa. Further, electric power was applied to generate a plasma so that the current density between the cathode 120 and the graphite electrode and the molybdenum electrode was 0.15 A / cm 2 (current / electrode area).

Arithmetic mean roughness Ra of the surface of the molybdenum electrode was 1.5 micrometers, and thermal conductivity (lambda) by the movement of a bulk was 132 W * m <^-1> k <^-1> . The arithmetic mean roughness Ra of the surface of the graphite made of the anode 112 was 5 µm, and the thermal conductivity λ of the bulk was 120 W · m ⁻¹ · k ⁻¹ .

Silicon having a thickness of 0.5 mm is used for the substrate 101, and in order to change the temperature of the substrate 101, the opposing surface 113a of FIG. 31 and the back surface 111c of the stage 111 are formed from about the deposition time of about 2 hours. ), The distance x was 60 mm. In the meantime, in the plasma CVD apparatus using the graphite electrode, a plurality of carbon flakes in the shape of petals (liquids) forming a curved surface stand on the substrate 101, and carbon nanowalls formed by connecting in a random direction are formed. Each carbon flake was a graphene sheet of several layers to several ten layers having a lattice spacing of 0.34 nm. Thereafter, the distance x was approached to 0.5 mm. The temperature of the substrate 101 was lowered by introducing helium gas as a cooling gas into the space 111b below the stage 111 at 500 sccm through the air vent 113e. In the plasma CVD apparatus using a graphite electrode, a microcrystalline diamond film, which is a layer containing a plurality of microcrystalline diamond particles having a particle diameter of nanometer (less than 1 μm), is deposited on a carbon nanowall on the substrate 101, and microcrystalline diamond is deposited. With the growth of the fine particles, part of the carbon nanowall grew mainly, and needle-shaped carbon rods were formed that penetrated the gap between the microcrystalline diamond film and protruded from the surface of the microcrystalline diamond film. This carbon rod is not a cylindrical structure in which carbon is formed to the inside, and is formed so that the inside becomes hollow in a thin carbon layer such as a carbon nanotube, but is rigid and grows from the carbon nanowall, so that the mechanical strength is strong.

A spectroradiometer is used to measure the temperature of the substrate 101, spectroscopically measures the infrared radiation intensity from the substrate 101, and evaluates the temperature and the emissivity of the substrate 101 by applying a gray body approximation. It was.

32 is a graph showing the measurement temperature of the substrate 101 due to the difference between the anodes 112.

As shown in Fig. 32, the temperature of the substrate 101 reaches the highest point within 30 minutes at the start of film formation in either of the electrodes, and thereafter, the temperature of the substrate 101 shows a tendency to fall in a state of constant current density. have. The reason why the temperature of the substrate 101 tends to decrease is that carbon nanowalls, which are aggregates of graphene sheets, are deposited on the substrate 101, so that the emissivity of the upper surface of the substrate 101 increases, and the substrate 101 This is because the amount of heat transfer due to radiation from the surface of the to the chamber increases. In addition, the temperature of the substrate 101 is stabilized after the emissivity of the substrate 101 reaches a constant value by depositing the carbon nanowall on the substrate 101. This phenomenon indicates that the peripheral emissivity greatly affects the temperature of the substrate 101 during the film formation by CVD such that the temperature of the substrate 101 exceeds 900 ° C.

Comparing the temperature of the substrate 101 by the electrode, in the initial film formation region in which the temperature of the substrate 101 varies greatly, the temperature of the substrate 101 on the graphite electrode is lower than that on the molybdenum electrode by at least 100 ° C. . In the state where the temperature thereafter is stable, even when the distance x is 0.5 mm, the temperature of the substrate 101 of the graphite electrode is 40 ° C lower than the temperature of the substrate 101 of the molybdenum electrode.

33 is a graph showing a change in power applied to the plasma in a state in which the applied current is made constant in the furnace operation of FIG. 32.

At the time of film formation, the current density flowing between the anode 112 and the cathode 120 is controlled to be constant at 0.15 A / cm 2, and the applied voltage automatically changes depending on the state of the gas. In practice, the lower the density of the gas between the electrodes, the more the applied voltage tends to decrease. In the case of the molybdenum electrode having a high temperature of the substrate 101, the surrounding gas temperature is increased by the substrate 101 and the electrode, and the density is reduced accordingly, so that the graphite electrode having the low temperature of the substrate 101 is reduced. The voltage for flowing the same current density becomes smaller. For this reason, the power applied in the case of the molybdenum electrode is always smaller than in the case of the graphite electrode, but the amount of change is 1.5% or less with respect to the applied power.

Although the applied power hardly changes, the reason why the temperature of the substrate 101 is always 100 degrees Celsius between the molybdenum electrode and the graphite electrode is that the graphite electrode is more likely to dissipate heat than the molybdenum electrode in this temperature range. Because it is. The reason that the thermal conductivity of molybdenum is small and the surface of the graphite electrode having a rough surface tends to dissipate heat can be explained by the fact that the contribution of thermal conductivity by heat radiation is greater than that of contact in both electrodes. If the thermal conductivity of the electrode material itself is not significant because of the high contact thermal resistance, for molybdenum having an emissivity of 0.9 or more, since molybdenum has only an emissivity of about 0.3 for reflection by the surface, the graphite electrode is on the substrate 101. It can be easily explained that the temperature of?

In addition, the higher the temperature of the substrate 101 is, the larger the temperature difference between the molybdenum electrode and the graphite electrode is. The heat conduction caused by the contact changes in proportion to the temperature difference. Since the heat transfer amount increases in proportion to the power, the heat transfer amount suddenly increased as the temperature of the substrate 101 increases, which corresponds to the difficulty in increasing the temperature. These also suggest that the ratio of heat radiation is large in the heat conduction in film-forming.

Here, in order to perform the estimation of the heat transfer amount by each heat transfer method, the case where the mirror-polished board | substrate is provided on the anode of surface roughness Ra is considered. If the surface y is the back surface of the substrate and the surface z is the surface of the anode, and the surface y of the substrate is the mirror surface, the surface roughness Ra of the anode can be roughly flat compared to the surface roughness Ra of the anode. It is considered to be delivered through. In this case, when the temperature of the substrate 101 is T ₁ and the anode temperature is T ₂ , the heat transfer amount W _t1 per unit area flowing between the substrate and the anode by contact is

It can be represented as Where λ is the thermal conductivity of the anode material, r is the ratio of the true contact area between the substrate 101 and the anode 112 to the apparent contact area between the substrate 101 and the anode 112, and Ra is the surface Arithmetic mean roughness of. In a more accurate equation, a correction term is introduced for the gap between the substrate 101 and the anode 112, but this is omitted since it is for the purpose of approximation.

In addition to the heat transfer by the contact between the solids described above, there is a heat conduction transferred through the gas in the gap between the substrate 101 and the anode 112. In consideration of the heat conduction through the stationary layer between the parallel plates having different temperatures, the average value in an atmosphere of 0.1 atm or less generally performed in plasma CVD when the data shown in FIG. 32 is obtained. Since the free path can be considered sufficiently larger than the surface roughness on the back side of the substrate, the heat transfer can be considered as a free molecular heat conduction. At this time, the heat amount W _g1 is

It can be represented as. Where: 자유: free molecular thermal conductivity, α: adaptive coefficient, p: pressure, γ: specific heat ratio, k: Boltzmann constant, and m: mass of gas molecules. For the sake of simplicity, the adaptation coefficient is calculated to be 1, the specific heat ratio is 7/5, and the mass of gas molecules is 3.3x10 ^-27 kg of hydrogen molecules, which are the main gases of plasma.

Finally, look at the heat transfer by radiation. Considering the anode as an infinite parallel plane, the heat transfer W _r1 transferred by heat radiation from plane y to plane z is

It is represented by Here, ε ₁ and ε ₂ are the emissivity of plane y and plane z, respectively, and σ is the Stefan Boltzmann coefficient (5.67 × 10 ^-8 Wm ^-2 K ^-4 ).

For these three electrothermal mechanisms, the emissivity of silicon to be the substrate is 0.6, the emissivity of molybdenum is 0.3, the emissivity of graphite is 0.9, and the substrate is in contact with the apparent contact area between the substrate 101 and the anode 112 ( Molybdenum electrode is calculated by calculating the heat transfer amount when the ratio of true contact area between 101) and anode 112 is 1/100000, substrate temperature is 920 ° C, and substrate area is □ 30 mm at anode temperature of 860 ° C. In the thermal contact with the substrate 101 is about 5W, the thermal conductivity between the molybdenum electrode and the substrate is about 10W, the heating by heat radiation is about 5W, whereas in the graphite electrode, the contact thermal conductivity with the substrate is About 1W, the thermal conductivity of the free molecules between the graphite electrode and the substrate 101 is about 10W, and the heating by heat radiation is about 11W. In this way, when stress is not applied to the interface and r becomes a very small value, the ratio of heat radiation not dependent on r and heat transfer due to free molecule thermal conduction increases.

In this case, when r is small, the case where the heat transfer from the plasma to the substrate is constant is considered. Even if the ratio r of the true contact area between the substrate and the anode with respect to the apparent contact area between the substrate and the anode is uneven due to misalignment, since the absolute value of r is small, the change in the amount of heat transferred from the substrate to the anode is changed. It hardly depends on heat transfer by radiation, and changes only the heat transfer amount due to the contact which changes in proportion to r. At this time, the greater the contribution of heat transfer by radiation, the greater the change in heat amount due to contact changes in proportion to (T ₁ ⁴ -T ₂ ⁴ ), so that the change in heat quantity is large with respect to temperature change, It is supplemented by the change of heat quantity, and the change amount of T1 can be made relatively small. As described above, the graphite electrode having a large contribution of thermal conductivity due to radiation can suppress unevenness of the substrate temperature due to the change of r with respect to the electrode having a smaller radiation rate, and stabilize the film forming conditions.

In addition, by using the anode 112 as a graphite electrode, it is shown below that unnecessary deposits can be prevented from being deposited on the anode 112.

34A and 34B are photographs showing the states of the molybdenum electrode and the graphite electrode after film formation, respectively.

In the case where the anode 112 is a molybdenum electrode, as shown in FIG. 34A, a carbonized film was formed in a portion where the substrate 101 was not mounted after film formation. For this reason, when a new board | substrate is arrange | positioned at the molybdenum electrode in which the carbonization film was formed, the surface roughness in the position in which the carbide film is formed becomes more uneven, and temperature control became more difficult by contact heat conduction.

On the other hand, since almost no deposits existed in the graphite electrode as shown in Fig. 34B, the surface roughness was not uneven and more stable temperature control was possible.

The resistance between the carbonized film of the molybdenum electrode and the back surface of the molybdenum electrode is 3 MΩ or more, and the nonuniformity of the applied voltage itself between the anode and the cathode has occurred, but the surface of the graphite electrode (regardless of the portion on which the substrate is mounted or not) The resistance between the back and the back surface did not change with the state before the film formation, and the applied voltage between the cathode and the cathode on the surface of the anode could be equal in-plane.

Thus, since the carbonization film which becomes an insulator on the anode 112 hardly deposits by using the anode 112 as a graphite electrode, the shape of the anode 112 substantially does not change during the film formation process, whereby the plasma shape The change can also be prevented, and stabilization of film formation can also be expected.

In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible.

As shown in FIG. 35, in order to increase thermal radiation, you may form the recessed part which can accommodate the board | substrate 101 in the board | substrate mounting surface 112a so that the thermal radiation surface of the anode 112 may be widened.

In this case, since the thickness of the anode 112 is equalized so that the temperature at the anode 112 is equal, the back side of the anode 112 is a convex portion protruding to match the depth of the recess of the anode 112. It is preferable to have a concave portion in the electrode mounting surface 111a of the stage 111 in accordance with the convex portion of the anode 112, and the thickness of the stage 111 is equal so that the temperature at the stage 111 is equalized. In order to make it easy, it is preferable that the back surface side of the stage 111 is a convex part which protruded to the depth of a recessed part in the electrode mounting surface 111a. And it is preferable that the recessed part is formed in the opposing surface 113a so that it may fit on the back surface side of the stage 111. FIG.

36, even if the back surface of the board | substrate 101 is not smooth, you may form a recessed part so that the board | substrate 101 may be fitted to the shape of the back surface of the board | substrate 101. Moreover, as shown in FIG.

In this case, in order to equalize the thickness of the anode 112 so that the temperature at the anode 112 is equal, the rear surface side of the anode 112 is a convex portion protruding to match the depth of the recess of the anode 112. It is preferable to have a concave portion formed on the electrode mounting surface 111a of the stage 111 in accordance with the block portion of the anode 112, and the thickness of the stage 111 is equal so that the temperature at the stage 111 is equalized. In order to make it possible, it is preferable that the back surface side of the stage 111 is a convex part which protruded to the depth of the recessed part in the electrode mounting surface 111a. And it is preferable that the recessed part is formed in the opposing surface 113a so that it may fit on the back surface side of the stage 111. FIG.

For example, the power supply 121 may not be configured to apply a DC voltage between the anode 112 and the cathode 120, or may be a plasma CVD apparatus that applies high frequency. Also in this case, by using graphite as the electrode for cooling the substrate 101, the substrate can be cooled by radiation of heat, and film formation can be stabilized.

In addition, various embodiments and modifications of the present invention can be made without departing from the broader spirit and scope of the present invention. In addition, embodiment mentioned above is for demonstrating this invention, and does not limit the scope of the present invention. That is, the scope of the present invention is shown not by embodiment but by Claim. And various modifications implemented within a claim and the meaning of the invention equivalent to it are considered within the scope of this invention.

1 is a configuration diagram showing a plasma CVD apparatus according to a first embodiment of the present invention;

2 is a plan view showing the ring nozzle and the exhaust port of FIG.

3A and 3B are views for explaining the configuration of a direct-current plasma CVD apparatus used in a comparative experiment;

4A is a view showing a state of glow generated in a cathode in the DC plasma CVD apparatus shown in FIGS. 3A and 3B;

4B is a diagram showing a glow state occurring in a cathode in the DC plasma CVD apparatus according to the first embodiment;

5A and 5B show the structure of a direct-current plasma CVD apparatus according to a second embodiment of the present invention;

6 is a configuration diagram of a direct-current plasma CVD apparatus according to a third embodiment of the present invention;

7 is a view showing an outline of a verification experiment;

8 is a diagram illustrating a result of a verification experiment;

9A to 9D are diagrams showing images illustrating the results of verification experiments;

(A) to (c) is a view showing the experimental results,

11 is a view showing experimental results,

12A and 12B are structural diagrams showing a direct-current plasma CVD apparatus according to a fourth embodiment of the present invention;

13 is a configuration diagram showing a direct-current plasma CVD apparatus according to a fifth embodiment of the present invention;

FIG. 14 is a view showing a cathode, a source gas nozzle, and an exhaust pipe of the DC plasma CVD apparatus of FIG. 13 from above;

FIG. 15 is a side cross-sectional view of the DC plasma CVD apparatus of FIG. 13;

16A and 16B are a schematic diagram of a direct-current plasma CVD apparatus according to a sixth embodiment of the present invention;

FIG. 17 is a view showing the cathode, source gas nozzle, and exhaust pipe of the DC plasma CVD apparatus of FIG. 16A from above;

18 is a side cross-sectional view of the direct-current plasma CVD apparatus of FIG. 16A;

19 is a configuration diagram of a direct-current plasma CVD apparatus according to the seventh embodiment of the present invention;

20 is a view showing the cathode, the reaction gas nozzle, the matrix gas nozzle, and the exhaust pipe of the DC plasma CVD apparatus of FIG. 19 from above;

21 is a sectional side view of the direct-current plasma CVD apparatus of FIG. 19;

22A and 22B are structural diagrams of a direct-current plasma CVD apparatus according to an eighth embodiment of the present invention;

FIG. 23 is a view showing a cathode, a reaction gas nozzle, a matrix gas nozzle, and an exhaust pipe of the DC plasma CVD apparatus of FIG. 22A from above;

FIG. 24 is a side cross-sectional view of the DC plasma CVD apparatus of FIG. 22A;

25 is a view showing a modification of the cathode;

26 is a view showing a modification of the cathode;

27 is a diagram showing a modification of the cathode;

28 is a diagram showing a modification of the cathode;

29 (a) and 29 (b) show a modification of the cooling member,

(A) and (b) are views showing a modification of the cooling member,

31 is a configuration diagram showing an outline of a plasma CVD apparatus according to a ninth embodiment of the present invention;

32 is a diagram illustrating a difference in temperature between a graphite electrode and a molybdenum electrode during film formation;

33 is a graph showing a change in power applied to a plasma;

34A and 34B are views showing the state of the anode after film formation;

35 is a configuration diagram showing an outline of a modification of the plasma CVD apparatus;

36 is a configuration diagram showing an outline of a modification of the plasma CVD apparatus;

37A is a diagram showing the configuration of a conventional plasma CVD apparatus, and FIG. 37B is a diagram for explaining the flow of gas in a reaction tank of the conventional plasma CVD apparatus shown in FIG. 37A.

Claims (24)

A first electrode disposed in the reaction tank, on which the substrate is mounted; A second electrode facing the first electrode above the first electrode and generating a plasma between the first electrode; A plurality of jets arranged at a height between a height of the first electrode and a height of the second electrode in the reactor, and arranged to surround a region where a plasma is generated between the first electrode and the second electrode; Is provided with a first gas introduction nozzle, The second electrode is composed of a plurality of electrodes, and the voltage or current between each electrode of the second electrode and the first electrode is set individually to a predetermined value, respectively. The method of claim 1, And a source gas into which active species are formed by the plasma is introduced by the first gas introduction nozzle. The method of claim 1, And a gaseous gas and a matrix gas into which active species are formed by said plasma are introduced by said first gas introduction nozzle. The method of claim 1, And the first gas introduction nozzle ejects gas from the plurality of jets in a transverse direction toward the central axis of the first electrode. The method of claim 1, And the first gas introduction nozzle is arranged to surround the first electrode. The method of claim 1, And said plurality of jets of said first gas introduction nozzle are arranged at equal intervals from each other. The method of claim 1, And said plurality of ejection openings of said first gas introduction nozzle are equal to each other at a distance from a central axis of said first electrode. The method of claim 1, A plasma CVD apparatus according to claim 1, wherein each of the pair of ejection openings consisting of two of the plurality of ejection openings of the first gas introduction nozzle is disposed to face each other with respect to the central axis of the first electrode. The method of claim 1, And the height of the jet port of the first gas introduction nozzle is at a position higher than the highest point of the region where the positive liquor of the plasma is generated. The method of claim 1, And the first gas introduction nozzle has a ring shape. The method of claim 1, And the first gas introduction nozzle is a tube facing each other along a side of the second electrode in the reactor. The method of claim 1, And a second gas introduction nozzle for ejecting a matrix gas from above the second electrode toward the gas ejected from the first gas introduction nozzle. The method of claim 1, And a plurality of discharge conduits for discharging gas from the reaction tank, disposed below the first electrode. The method of claim 1, And a plurality of discharge conduits disposed below the first electrode and arranged to surround the first electrode to discharge gas from the reaction tank. delete The method of claim 1, The plurality of electrodes includes a central electrode facing the central portion of the first electrode and a peripheral electrode facing the peripheral portion of the first electrode, In the rising, the voltage or current value between the center electrode and the first electrode is set higher than the voltage or current value between the peripheral electrode and the first electrode. The method of claim 1, The plurality of electrodes includes a central electrode facing the central portion of the first electrode and a peripheral electrode facing the peripheral portion of the first electrode, After the positive column is formed between the center electrode and the first electrode, the voltage or current value between the center electrode and the first electrode is less than the voltage or current value between the peripheral electrode and the first electrode. Plasma CVD apparatus, characterized in that. The method of claim 1, An insulator is disposed between the plurality of electrodes. The method of claim 1, And said first electrode has a surface formed of graphite. An electrode having a substrate placing surface on which a substrate to be processed is mounted, a recess in which the substrate can be stored is formed on the substrate placing surface, and the surface of which is formed of graphite; And plasma generating means for forming a carbon film on the substrate by generating a plasma on the electrode using hydrocarbon as a reaction gas while a part of the electrode is exposed to the periphery of the substrate. The method of claim 20, And a stage for supporting the electrode, And cooling means for cooling the electrode to lower the substrate temperature by cooling the stage. The method of claim 21, And the cooling means starts cooling the substrate when film formation is performed on the substrate. delete A voltage or current which is individually set to a predetermined value between the first electrode on which the substrate is mounted and the second electrode composed of a plurality of electrodes, and between each electrode of the second electrode and the first electrode, respectively. And spraying the reaction gas from a plurality of jets arranged to surround the region where the plasma is generated.

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