JP2005197393A - Electrode-burying member for plasma generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode-burying member for generating plasma for maintaining quality stably for a long time, by reliably preventing the destruction of a ceramic substrate caused by thermal stress generated at the adhesion section between an electrode for generating plasma and a power feeding terminal. <P>SOLUTION: In the electrode-burying member 10 for plasma generators, the power feeding terminal 23 is arranged closer to the outer periphery of the ceramic substrate 11 in the electrode burying member 10 in which the electrode 112 for generating plasma is buried into the ceramic substrate 11 and the power feeding terminal 23 is connected to one surface of the electrode 112. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electrode embedding member for a plasma generator used for processing a silicon wafer or the like in a plasma production atmosphere in the field of semiconductor manufacturing.

  Generally, a stainless steel heater and an electrode tube are disposed in a semiconductor manufacturing apparatus such as an etching apparatus or a chemical vapor deposition apparatus used in the semiconductor manufacturing field. However, such semiconductor manufacturing apparatuses are often used in a highly reactive fluorine-based or chlorine-based halogen-based corrosive gas generation atmosphere as a deposition gas, etching gas, or cleaning gas. There has been a problem that apparatus constituent members such as steel and Inconel react with these corrosive gases to generate particles in the apparatus. In order to solve such a problem, a resistance heating element or the like is conventionally embedded in a ceramic substrate.

  Among such semiconductor manufacturing apparatuses, a plasma generating apparatus in which an electrode for generating a plasma is embedded in a ceramic substrate is required to have excellent corrosion resistance against halogen-based corrosive gas and at the same time excellent plasma resistance. . In addition, when performing a predetermined process on a silicon wafer or the like, this plasma generator is used to generate a high frequency between the plasma generating electrode and the other plasma generating electrode separately provided above the wafer (workpiece). A film is formed by applying a voltage to generate plasma, or an etching gas is supplied to apply a predetermined treatment to a silicon wafer or the like.

By the way, in the plasma generating apparatus, a pair of plasma generating electrodes are disposed in a ceramic substrate on which a wafer is placed and above the ceramic substrate, and a high frequency voltage is applied between these electrodes. Necessary processing is performed by generating plasma. In this case, the electrons charged in the lower plasma generating electrode embedded in the ceramic substrate flow through the power supply terminal connected to the plasma generating electrode. At this time, a large Joule heat is generated at the connection portion between the plasma generating electrode and the power supply terminal, which causes the connection portion to generate heat, thereby inducing the generation of thermal stress and thus inducing the destruction of the ceramic substrate. was there.
Conventionally, in Patent Document 1, in order to make it easy to pass a current, such a problem is devised to suppress the heat generation by using a plurality of thin electrodes stacked, and in Patent Document 2, Proposes a technology that prevents the concentration of thermal stress at specific locations by connecting via holes and conductive layers between the electrodes and keeping the via holes and feed terminals close to each other. doing.
JP-A-11-162698 Japanese Patent Laid-Open No. 9-213455

  However, in the case of the prior art described in the above-mentioned Patent Documents 1 and 2, even if a plurality of plasma generating electrodes are used as a laminated material and the position of the power supply terminal is separated from the via hole, it is embedded in the ceramic substrate. The flow rate of the charged electrons in the generated plasma generation electrode does not decrease, and thermal stress that cannot be ignored still occurs at the junction between the plasma generation electrode and the power supply terminal, and the ceramic substrate may be destroyed. .

  The object of the present invention can reliably prevent the destruction of the ceramic substrate due to the thermal stress caused by the heat generated at the connecting portion between the electrode for plasma generation and the power supply terminal even if it is used for a long time at a high temperature, An object of the present invention is to provide a plasma generating electrode burying member capable of maintaining the quality in a stable state over a long period of time.

As described above, conventional electrode-embedded members, particularly members formed by embedding a plasma generating electrode in a ceramic substrate, are subjected to the above-mentioned plasma when a high frequency, for example (13.56 MHz, 2.5 kW) is applied at a high temperature for a long time. Electrons on the surface of the generating electrode flow on the surface of the power supply terminal as they are due to the skin effect, so that sudden heat generation occurs at the connection between the electrode and the terminal, eventually generating thermal stress near the power supply terminal in the ceramic substrate. There is a problem that the substrate is destroyed. Therefore, in the present invention, the present invention has been developed with the knowledge that it is effective to employ the following configuration to solve such problems.
That is, according to the present invention, an electrode for plasma generation is embedded in a ceramic substrate, and in the electrode embedding member in which the power supply terminal is connected to one surface of the electrode, the power supply terminal is disposed near the outer periphery of the ceramic substrate. This is an electrode embedding member for a plasma generator.
In the above configuration of the present invention, the feed terminal is disposed in a region corresponding to 20% of the diameter in the radial direction from the outer periphery of the ceramic substrate, and the plasma generating electrode is made conductive. It has been found preferable to use carbide ceramics or conductive nitride ceramics.

  In the present invention, the reason why the position of the power feeding terminal is set as described above is as follows. As described above, the plasma generation electrode and the power supply terminal connection portion concentrates electrons on the surface of the power supply terminal, generates large Joule heat, and the vicinity of the adhesion surface of the power supply terminal of the plasma generation electrode and the power supply terminal It becomes hot. Therefore, when there are a plurality of power supply terminals, it can be said that it is desirable to dispose these at remote positions. Furthermore, since the ceramic substrate emits heat more in the vicinity of the outer periphery than in the vicinity of the center of the ceramic substrate, it can be said that it is desirable to arrange the heat generation part near the outer periphery of the substrate where the heat emission is large. Therefore, in the present invention, by installing the power supply terminal in the outer peripheral portion that is within 20% of the diameter in the radial direction from the outer peripheral edge of the ceramic substrate, abnormalities in the connection portion between the plasma generating electrode and the power supply terminal are detected. I decided to suppress the fever.

In the present invention, the reason why the feed terminal is disposed in the region within 20% of the diameter in the radial direction from the outer peripheral edge of the ceramic substrate is that the feed terminal is disposed inside 20%, The interval between the high temperature regions formed by the heat generated at the junction of the plasma generating electrode is reduced, so that a large high temperature region is formed at the center of the plasma generating electrode, and the wafer processing surface of the plasma generating member is formed. This is because not only the temperature uniformity is deteriorated, but also the substrate is destroyed by the thermal stress caused by the temperature difference.
Accordingly, in the present invention, the power supply terminal is arranged within 20% of the diameter from the green outer periphery of the ceramic substrate in the radial direction, preferably 5% to 15% in order to further enhance the above effect. If the arrangement position is outside 5%, it is located on the outermost peripheral portion of the plasma generating electrode, so that the boundary between the electrode and the ceramic of the substrate material becomes a high temperature region, and is greatly affected by thermal stress. Become.

  In addition, as a result of continuing earnest research on the above-mentioned problems, the inventors have provided a plurality of unevenness along the axial direction, particularly unevenness strips, on the outer surface of the power supply terminal connected to the plasma generating electrode. In this case, it was found that the present invention is more effective in suppressing abnormal heat generation at the connecting portion between the plasma generating electrode and the power supply terminal and a large thermal stress. The reason is that, generally, in a plasma generator, a high frequency is applied for a long time at a high temperature. At this time, electrons charged on the surface of the plasma generating electrode embedded in the ceramic substrate are affected by the skin effect. All flows only in the surface layer portion of the power supply terminal connected thereto, and therefore, the temperature of this portion becomes higher than that of the peripheral portion, and a large temperature difference is generated inside the ceramic substrate. Therefore, the larger the surface area of the electrode and the power supply terminal, the smaller the density of electrons flowing on the surface, so that the generation of thermal stress can be reduced. Therefore, in the present invention, in addition to the above-described arrangement of the feed terminal, the generation of thermal stress due to Joule heat generated at the surface layer portion of the plasma generating electrode and the feed terminal, particularly the connection portion, is suppressed as necessary. Therefore, the surface of the power supply terminal connected to the electrode for plasma generation is provided with irregularities to increase the surface area. For example, as a form of unevenness provided on the electrode bottom surface and the outer surface of the power supply terminal connected to the bottom surface, in the cross section orthogonal to the axial direction, the shape of the outer peripheral portion is a petal shape, a star shape, etc. A plurality of concavo-convex ridges formed along the direction were provided to increase the area, thereby effectively preventing the destruction of the ceramic substrate due to the abnormal heat generation and thermal stress described above.

  Conductive ceramics are used as the plasma generating electrode used in the present invention. In general, in a conventional electrode-embedded member used in a halogen-based corrosive gas and plasma generation atmosphere, for example, a member using carbon-containing aluminum nitride as a ceramic substrate, the contained carbon and the material for the embedded electrode in the ceramic substrate are used. It is known that metal Mo and metal W react to generate carbide. As a result, the volume resistivity as a member increases and there is a big problem that the plasma generation density becomes non-uniform. Therefore, as the plasma generating electrode used in the member according to the present invention, conductive ceramics are used instead of metal. The reason is that when conductive ceramics are used as the electrode material, the increase in volume resistivity can be suppressed.

  Conductive ceramics made of carbide or nitride used for the electrode material has a characteristic of low reactivity with carbon (C). That is, when firing or when used for a long time at 500 ° C. or higher (plasma CVD film formation temperature), the electrode component does not react with C contained in the ceramic substrate, and the resistance value changes with time. Absent. Among them, since the carbide ceramics are pre-carburized, there is no further reaction with C, and therefore there is no change in resistance over time, so that the plasma density can be maintained stably and uniformly over a long period of time. Can do.

  In this regard, when metals such as Mo and W are used as plasma generating electrodes as in the prior art, these metals become intense in lattice vibration as the temperature rises, preventing the free movement of electrons. As a result, the volume resistivity is increased. For this reason, when the voltage is constant, there is a problem in that the current flow rate is lowered and the temperature rise is difficult. On the other hand, when conductive ceramics, particularly conductive carbide ceramics are used, the volume resistivity decreases as the temperature rises, so that a large current can be input at a high temperature. As a result, plasma is easily generated.

  As a specific example of the plasma generating electrode, for example, a sintered body having a plate-like cross-sectional shape obtained by firing particles of tungsten carbide (tungsten carbide) can be used. In addition, the size of the tungsten carbide particles as a raw material is an arbitrary two-dimensional cross-sectional view, for example, a cross-sectional view in the thickness direction of the ceramic substrate, and the particle diameter is in the range of 1 μm to 10 μm (minimum short diameter: 1 μm , Maximum major axis: 10 μm) is desirable. The reason is that when the particle size is less than 1 μm, the reactivity is high and the material is easily oxidized, so that the resistance value is increased by reacting with oxygen in the ceramic substrate during use. On the other hand, when the particle size is 10 μm or more, the sinterability is lowered, the resistance value is still high, and the current density in the electrode varies, so that uniform plasma cannot be generated.

  In the embodiment of the present invention, it is preferable to embed a plasma generating electrode made of conductive carbide ceramic in an insulating nitride ceramic substrate. Insulating nitride ceramic substrate has excellent heat resistance and mechanical characteristics, strong corrosion resistance and durability against halogen-based corrosive gas and plasma, high thermal conductivity, and excellent temperature followability. . Moreover, this insulating nitride ceramic has a characteristic that the thermal expansion coefficient is close to that of the buried electrode, and therefore, cracks due to thermal shock do not occur. In addition, this insulating nitride ceramic has a higher volume resistivity at high temperatures than that of insulating carbide ceramics, so that a large current can flow without causing an electrical short circuit. It is advantageous to uniformly generate.

  As the ceramic substrate used in the present invention, nitride ceramics, carbide ceramics, oxide ceramics and the like can be used. Examples of the nitride ceramics include aluminum nitride, silicon nitride, boron nitride, titanium nitride and the like. As an example of the above-mentioned carbide ceramics, silicon carbide (in addition, silicon carbide exhibits insulating properties when the purity is high, while it exhibits conductivity due to the conductivity of carbon when the purity is low. When used as the ceramic substrate, high-purity silicon carbide is used), zirconium carbide, boron carbide, titanium carbide, tantalum carbide, tungsten carbide and the like. As the oxide ceramic, alumina, silica, cordierite, mullite, zirconia, beryllia, or the like can be used. These ceramic materials may be used alone, or may be a mixture of two or more.

  Of these, nitride ceramics and carbide ceramics are preferred. The reason for this is that the above-mentioned nitride ceramics and carbide ceramics have a thermal expansion coefficient smaller than that of metal, and mechanical strength is much higher than that of metal. Therefore, even if the thickness of the ceramic substrate is reduced, it may be warped or distorted by heating. This is because the ceramic substrate can be made thin and light. In particular, since these ceramic substrates have high thermal conductivity, if they are thinned, the substrate surface temperature quickly follows the temperature changes of the heater electrode when the heater temperature is changed by changing the voltage or current amount. Easy and temperature control becomes easy. In particular, nitride ceramics are more preferable. The reason is that nitride ceramics are excellent in heat resistance and mechanical properties and have high thermal conductivity, and aluminum nitride is particularly preferable. This is because aluminum nitride has a high thermal conductivity of 180 W / m · K at room temperature, and the temperature followability of the ceramic substrate is most excellent.

  Note that the ceramic substrate also has carbon of 200 ppm or more, preferably about 200 to 1000 ppm. By containing C in the ceramic substrate at 200 ppm or more, the brightness of the ceramic substrate can be made N6 or less as a value based on the JIS Z 8721 standard. The ceramic substrate having such brightness is excellent in the amount of radiant heat and concealment. In addition, such a ceramic substrate enables accurate surface temperature measurement by a thermoviewer. As a method for analyzing the carbon contained in the ceramic substrate, it is preferable to use a method defined in JIS Z 2615 (1996) as an oxygen gas combustion-infrared absorption method.

  As the carbon, both amorphous and crystalline carbon can be used. Amorphous carbon suppresses the decrease in volume resistivity of ceramic substrates at high temperatures, and crystalline carbon suppresses the decrease in thermal conductivity of ceramic substrates at high temperatures. It is desirable to appropriately select and use the type of carbon according to the purpose and the like.

  The shape of the ceramic substrate 11 is preferably a disk shape, and the size is 200 mm or more, more preferably 250 mm or more in diameter. This is because the ceramic substrate having such a size can mount a large-diameter semiconductor wafer when the plasma generator is used in the field of semiconductor manufacturing.

  The surface of the ceramic substrate on the wafer processing side preferably has a surface roughness based on JIS B 0601 of about 0.05 to 2.0 μm in Ra. The reason for this is that when the surface roughness Ra is less than 0.05 μm, the adhesion between the silicon wafer and the ceramic substrate becomes high, and yttrium added as a sintering aid in the ceramic substrate reacts with the silicon wafer during high-temperature processing. This is because the silicon wafer is contaminated. On the other hand, when the surface roughness Ra of the surface on the wafer processing side exceeds 2.0 μm, the temperature distribution of the wafer varies in the heat treatment or the like, and the wafer surface cannot be processed uniformly. . A preferable surface roughness Ra is 0.1 to 1.2 μm.

  The thickness of the ceramic substrate 11 is desirably 5 mm or more and 20 mm or less. The reason is that if the thickness is less than 5 mm, the strength of the ceramic substrate itself is reduced, so that the ceramic substrate is easily damaged. On the other hand, if the thickness exceeds 20 mm, the temperature followability may be lowered. A more desirable lower limit is 12 mm, and a more desirable upper limit is 16 mm. The reason for this is that if the thickness is less than 12 mm, the heat propagated in the ceramic substrate will not be sufficiently diffused, resulting in temperature variations on the heating surface, and the strength of the ceramic substrate may be reduced and damaged. is there. On the other hand, when the thickness exceeds 16 mm, heat hardly propagates through the ceramic substrate, and the heating efficiency tends to decrease.

  In the present invention, a heater electrode may be embedded in the ceramic substrate together with the plasma generating electrode. In this case, the heater electrode is also embedded in the ceramic substrate. This is because these electrodes are prevented from being exposed to a corrosive plasma gas atmosphere, and temperature control can be performed more quickly in the ceramic substrate.

  As described above, according to the electrode embedding member for a plasma generator according to the present invention, even when a ceramic substrate is fired or used at a high temperature for a long time, various electrodes embedded in the substrate, particularly plasma generating electrodes. Not only does the volume resistivity change small, but it can suppress the generation of thermal stress at the connection between the electrode and the terminal, so there is little destruction of the substrate, excellent corrosion resistance and durability, and the quality can be kept stable for a long time. .

  FIG. 1 is a partial sectional view showing an example of an electrode embedding member for a plasma generator according to the present invention. As shown in this figure, an electrode embedding member 10 of a plasma generating apparatus having a configuration suitable for the present invention is mainly composed of a ceramic substrate 11 and a plasma generating electrode having a plate-like cross section embedded in the substrate 11. 112 and the heater electrode 12. In order to expose the through holes 113 and 13 serving as power supply terminals and the through holes 113 and 13 to the base bottom surface 11b on the bottom surface of the plasma generating electrode 112 opposite to the surface on which the silicon wafer is placed. External terminals 23, 23 'are formed. Although not shown in the figure, a ceramic terminal protection cylinder may be joined to the bottom surface 11b of the ceramic substrate 11 if necessary. On the other hand, the upper surface 11a of the ceramic substrate 11 is A plurality of protrusions 11c for supporting the wafer are provided.

  As described above, the member according to the present invention is characterized in that at least the power supply terminal (through hole 113) is 20% of the diameter D from the outer peripheral edge of the substrate 11 in the radial direction, that is, 0.2D. It is to arrange within the range. In some cases, it is preferable to arrange the through hole 13 of the heater electrode 12 so as to be within the outer periphery of the substrate, that is, within a range of 0.2D. Such an arrangement makes it possible to eliminate the adverse effect caused by Joule heat generated at the connection portion between the electrode and the terminal.

  Furthermore, the feed terminal through-hole 113 and heater electrode through-hole 13 arranged as described above, especially the through-hole (feed terminal) 113 connected to the plasma generating electrode 112 are affected by the skin effect described above. In consideration, it is desirable to provide a large number of irregularities on the outer periphery, more preferably irregularities provided along the axial direction so that the surface area becomes larger. For example, the shape of the horizontal cross section orthogonal to the axial direction may be a petal shape or a star shape.

  Note that the power supply terminal is not limited to the hollow material as long as the outer periphery is provided with irregularities, and a cylindrical terminal may be used. In this case, the through hole 113 is not the one in which the conductive paste is densely filled in the hole, but the conductive paste is applied to the inner wall of the hole to form a cylindrical shape, that is, the hole is filled with the conductive paste. However, it is good to form so that the center part may become a cavity. And as such a power supply terminal, as shown to Fig.7 (a)-(d), after apply | coating an electrically conductive paste and making it a cylindrical body, it dries at atmospheric pressure at 80 degreeC for about 5 hours. Then, the cavity is preferably filled with an aluminum nitride paste. In this manner, the horizontal cross-sectional shape may be a feeding terminal of a petal-like cylindrical body or a cylindrical body having a star-shaped cross section (FIGS. 7A to 7D). The external terminals 23 and 23 ′ and the conductive wire 24 are connected to each other through power supply terminals formed in these through holes 113. Note that the above-described through hole is a conductor formed on the inner wall portion of the hole used for electrically connecting the plasma generating electrode 112, the heater electrode 12, the electrostatic electrode, or the like to the external terminals 23 and 23 ′. Refers to a hole.

  Examples of the material constituting the through holes 113 and 13 constituting the power supply terminal include noble metals such as gold, silver, platinum and palladium, metals such as lead, tungsten, molybdenum and nickel or alloys thereof, tungsten and molybdenum. A conductive ceramic such as carbide is preferably used.

  A pad portion is provided between the through holes 113 and 13 serving as power supply terminals and the plasma generating electrode 112 or the heater electrode 12 in order to increase the connection area as necessary to ensure conduction and increase the adhesive force. It is desirable to form 19c. As a material constituting the pad portion 19c, any material having conductivity may be used. For example, the same material as the electrode material or the through hole may be used, and a metal (W, Mo) alloy or a mixture thereof. It may be.

  When the above-mentioned electrode burying member for a plasma generator is applied to a semiconductor manufacturing apparatus, the ceramic substrate 11 is usually fixed in a support container having a bottom plate on the side opposite to the surface on which the silicon wafer is placed. In addition, for example, if a terminal protection cylinder (not shown) is provided below the ceramic substrate 11 and the inside thereof is kept airtight, the periphery of the ceramic substrate 11 is exposed to a corrosive gas atmosphere such as reactive gas or halogen gas. Even if it is exposed, the external terminal 23 and the like housed in the terminal protection cylinder do not come into direct contact with the corrosive gas.

  The plasma generating electrode 112 is made of conductive ceramics, but it is not a metal carbonized by firing at the time of use, but one that has already become tungsten carbide or molybdenum carbide. These conductive ceramics may be used alone or in combination of two or more. Of these, tungsten carbide is more preferable.

  The thickness of the plasma generating electrode 112 is preferably about 5 μm to 300 μm. The measured value of the thickness of this electrode layer is obtained by cutting the ceramic substrate 11 in which the plasma generating electrode is embedded in a direction perpendicular to the plate surface, and two plasma generating electrodes and a ceramic substrate observed at that time. In order to prevent variation in the distance between the boundaries between the two locations, arbitrary 10 locations were measured and the average value was used. If this thickness is less than 5 μm, the degree of variation in the thickness of the electrode layer is greatly affected, so that the variation in resistance value is large and the plasma distribution is not constant, so that the vapor phase growth surface formed on the wafer surface The thickness variation of becomes large. On the other hand, if it exceeds 300 μm, cracks occur at high temperatures.

  As the conductive ceramic used for the electrode, one having a particle diameter of 0.1 to 10 μm is used. This is because if the thickness is less than 0.1 μm, oxidation tends to occur. On the other hand, if it exceeds 10 μm, it becomes difficult to sinter and the resistance value increases. The definition of the particle size defines the range of the minimum minor axis and the maximum major axis in an arbitrary two-dimensional sectional view as described above.

  In order to form a layer of the plasma generating electrode 113 embedded in the ceramic substrate 11, it is preferable to use a conductor green sheet or a conductor paste. When using a conductor green sheet, it is desirable that the conductor green sheet is punched into a pattern, and then laminated on an insulating green sheet to be a ceramic substrate and fired.

  The conductor green sheet contains conductive ceramic particles, and may contain various resins, solvents, thickeners and the like. As the resin, an epoxy resin, a phenol resin, or the like can be used. As the solvent, isopropyl alcohol or the like can be used. As the thickener, cellulose or the like can be used. It is not limited.

  In addition, when the electrode for plasma generation is formed by the conductor paste method, the conductor paste layer is formed on the insulating ceramic green sheet by the screen printing method, and then another ceramic not printed. The plasma generation electrode layer may be embedded in the ceramic substrate by stacking and firing the green sheets.

  In addition to the conductive ceramic particles, various resins, solvents, thickeners, and the like may be added to the conductive ceramic paste. Examples of the resin include epoxy resins and phenol resins, examples of the solvent include isopropyl alcohol, and examples of the thickener include cellulose and the like. It is not limited.

  2 (a) to 2 (c) are plan views showing a preferred example of the shape of the electrode for plasma generation embedded in the electrode embedding member for the plasma generator of the present invention. FIG. 2 (a) is a circular plane type. 2 (b) and 2 (c) have a mesh pattern formed by regularly drilling circular or square openings 112h in a circular plane type. It is an example of the electrode for plasma generation.

  2 (b) and 2 (c) is an electrode layer made of a plate-like body having a large number of openings 112h, and has a large number of openings 112h, so that the ceramic particles are ceramic green. It flows when the sheets are laminated, and the bonding strength of the ceramic is improved and the strength is improved. Further, due to the difference in thermal expansion coefficient between the ceramic substrate 11 and the plasma generating electrode 112, stress may be generated in the vicinity of these contact portions and the ceramic substrate 11 may be damaged. This is useful in that the above risk is avoided.

  The electrode for a plasma generator shown in FIG. 2C is a mesh-like mesh body, and the aperture ratio is adjusted to about 4 ≦ x <40%.

  FIG. 3 shows an example in which a plurality of plasma generator electrodes 112 are embedded in a ceramic substrate 11 as a set. In general, when a high frequency is applied to a plasma generating electrode, it is difficult for the high frequency to flow if the layer thickness of the electrode is thin. Occur. For this reason, this electrode is preferably made into a multilayer of two or more layers because it may cause damage to the ceramic substrate.

  On the other hand, FIG. 4 is a cross-sectional view showing a form in which the circular plasma generating electrode 112 and the like are divided into four parts.

  Next, the external terminals 23 and 23 'connected to the power supply terminals (through holes 113 and 13) are preferably T-shaped in a cross-sectional view as shown in FIG. A member having a thread groove at the end may be used. When the external terminal is screwed, it is desirable to form a screw hole into which the screw of the external terminal 23 can be screwed into the through holes 113 and 13.

  As the material of the external terminal 23, for example, a metal such as nickel or tungsten can be used. The size of the external terminal 23 is appropriately adjusted according to the shape of the through hole (feeding terminal) provided satisfying the condition of the above formula (1) and further according to the size of the ceramic substrate to be used. For example, when using an external terminal having a thread formed on the outer periphery and inside, the preferred lower limit of the diameter of the shaft portion is about 2.0 mm, and the preferred upper limit is about 8.0 mm, and the length of the shaft portion The preferred lower limit is about 5.0 mm, and the preferred upper limit is about 12.0 mm.

  As shown in FIG. 1, the bottom surface of the ceramic substrate 11 is provided with a bottomed hole 14 drilled toward the heating surface, and the bottom of the bottomed hole 14 is heated more than the heater electrode embedding position. A temperature measuring element 180 such as a thermocouple is attached in the bottomed hole 14. The temperature of the substrate can be measured by the temperature measuring element 180, and the temperature can be controlled by changing the voltage and current amount to the heater electrode 12 based on the data.

  Moreover, as shown in FIG. 1, it is desirable to provide the through-hole 15 for inserting a lifter pin (not shown) in the part away from the center of the ceramic substrate 11.

  The surface of the ceramic substrate 11 on the silicon wafer mounting side is preferably provided with a plurality of protrusions 11c for supporting the wafer by embossing, and the surface of the protrusions 11c is roughened by blasting. Is more preferable. In addition, by supporting the semiconductor wafer on the heating surface of the substrate through the projections 11c formed on the substrate, the semiconductor wafer can be heated while being separated from the heating surface by 5 to 300 μm.

  Hereinafter, an example of a method for producing an electrode embedding member for a plasma generator according to the present invention will be described with reference to FIG.

(1) Green Sheet and Power Supply Terminal Manufacturing Process First, a ceramic powder is mixed with a binder, a solvent, and the like to prepare a paste, which is formed into a sheet shape by a doctor blade method, and a green sheet 110 is manufactured. As the ceramic powder, aluminum nitride or the like can be used, and if necessary, a sintering aid such as yttria, a compound containing Na, Ca, or the like may be added. The binder is preferably at least one selected from the group consisting of an acrylic binder, ethyl cellulose, butyl cellosolve, and polyvinyl alcohol. As the solvent, α-terpineol and / or glycol is desirable.

  The thickness of the green sheet 110 is preferably about 0.1 to 2.0 mm. For a predetermined green sheet 110, a through hole 113 for forming a power supply terminal for connecting to a plasma generating electrode or a heater electrode, a through hole, or an existence is provided. A portion (hole) to be a bottom hole may be formed in advance, or may be formed after the green sheet laminate is produced and fired. About the above-mentioned Sue hole 113, the inside of the hole is not completely filled with the conductive paste, but after the conductive paste is applied only to the hole wall portion so that the center becomes a hollow (tubular), It may be dried at atmospheric pressure and 80 ° C. for 5 hours, and finally the aluminum nitride paste is filled in the cavity to form a paste filling layer 133, which is used as the power supply terminal 113.

(2) Step of forming a conductive paste layer on the green sheet A conductive paste layer 122 that becomes a plasma generating electrode 112 by printing a tungsten carbide (WC) paste on the green sheet 110 or punching out the tungsten carbide green sheet in a pattern. Then, a heater electrode (WC carbonized heating element pattern layer) 12 formed by punching a tungsten carbide (WC) green sheet is sandwiched between the green sheets 110, and a pattern layer 120 made of tungsten carbide serving as the heater electrode 12 is formed. The conductive paste filling layer 130 filled in the end portion and the portion that becomes the through hole is printed and formed, and the conductive paste layer 122 serving as the plasma generating electrode 112 is formed thereon, and the through hole and Fill the part with conductor paste Forming a Hamaso 133, and the conductive paste filling layer 133 filled to print so as to overlap the end portion and the portion to be a through-hole of said conductive paste layer 122. As these conductor pastes, those containing metal particles or conductive ceramic particles are preferably used.

  The tungsten carbide particles and molybdenum carbide particles used as the green sheet preferably have an average particle size of about 0.1 to 10 μm. The reason is that when the particle size is less than 0.1 μm or exceeds 10 μm, it is difficult to print the conductor paste.

  Examples of such a conductive paste include 85 to 87 parts by weight of conductive ceramic particles; 1.5 to 10 parts by weight of at least one binder selected from the group consisting of acrylic, ethyl cellulose, butyl cellosolve, and polyvinyl alcohol; α-terpineol In addition, a composition (paste) or the like in which 1.5 to 10 parts by weight of a solvent composed of glycol is mixed can be used. The conductor paste used for the conductor paste filling layers 130 and 133 filled in the portions to be through holes and the conductor paste used for the conductor paste layers 120 and 122 may have the same composition or different compositions. A thing may be used.

(3) Green Sheet Lamination Step The green sheet 110 on which the tungsten carbide (WC) heater electrode pattern layer 120 is not formed is laminated on the green sheet 110 on which the conductive paste layer 122 is formed, and a cylindrical shape is formed thereunder. The green sheets 110 on which only the conductive paste filling layer 133 is formed are superposed. Then, the green sheet 110 on which the tungsten carbide (WC) heater electrode pattern layer 120 is formed is overlaid on the green sheet 110, and further, the conductor paste filling layers 130 and 133 each having a cylindrical shape are formed thereon. The green sheets 110 are stacked, and the green sheets 110 that are not processed are further stacked (FIG. 5A).

  At this time, the number of the green sheets 110 laminated on the upper side of the green sheet 110 on which the conductive paste layer 120 is formed is made larger than the number of the green sheets 110 laminated on the lower side, so that the heater electrode to be manufactured is formed on the bottom side. Eccentric in the direction of. Specifically, it is desirable that the upper green sheet 110 is stacked on the order of 5 to 20 and the lower green sheet 110 is stacked on the order of 50 to 70.

(4) Green sheet laminate firing step Next, the green sheet laminate is pressurized and heated to fire the green sheet 110 and the internal conductor paste layers 120, 122, etc. A heater electrode 12, a plasma generating electrode 112, through holes 13, 113, and the like are manufactured. (Fig. 5 (b))
A desirable lower limit of the heating temperature for the firing is 1000 ° C., and a desirable upper limit is 2100 ° C. Heating is performed in an inert gas atmosphere or in a vacuum. As the inert gas, for example, argon, nitrogen or the like can be used. A desirable lower limit of the pressure of pressurization is 10 MPa, and a desirable upper limit is 20 MPa.

  A portion to be a through hole into which a lifter pin for transporting an object to be heated such as a semiconductor wafer is inserted is formed after the green sheets 110 are laminated and fired. Formation is performed by drilling.

  Next, a bag hole 19 is formed in the bottom surface 11b of the ceramic substrate 11 by drilling.

(5) Manufacturing process of substantially cylindrical terminal protection cylinder Ceramic powder such as aluminum nitride powder is molded in a cylindrical mold and cut as necessary, and then heated at a temperature of 1000- The cylindrical ceramic body 17 is manufactured by sintering at 2100 ° C. and normal pressure. At this time, it is desirable that the cylindrical ceramic body to be manufactured is substantially cylindrical. The heating for the sintering is performed in an inert gas atmosphere or in a vacuum. As the inert gas, for example, argon, nitrogen or the like can be used. Next, the end surface of the ceramic body 17 is polished and flattened.

(6) Joining process of ceramic substrate and ceramic body In a state where the end surface of the terminal protection cylinder 17 is in contact with the vicinity of the center of the bottom surface of the ceramic substrate 11, the ceramic substrate 11 and the terminal protection cylinder 17 are heated, Join. At this time, the through holes 113 and 13 for the power supply terminals are joined inside the ceramic body 17 (FIG. 5C).

  As a method for joining the ceramic substrate 11 and the terminal protection cylinder 17, for example, the sintering aid is set so that the concentration of the sintering aid inside the ceramic substrate 11 and the concentration of the sintering aid inside the terminal protection cylinder 17 are different. After containing an agent and bringing them into contact at the joining position, they are joined by heating. In this case, the sintering aid moves from a member having a high concentration of sintering aid to a member having a low concentration, and particles grow across the interface to form a firm joint surface.

Other methods for joining the ceramic substrate 11 and the terminal protection cylinder 17 include, for example,
(1) A method (diffusion bonding) in which a solution containing a sintering aid of a ceramic material constituting these is applied to the bonding surfaces of the ceramic substrate 11 and the terminal protection cylinder 17 and fired (diffusion bonding),
(2) A method of firing after applying a ceramic paste having the same main component as the ceramic constituting the ceramic substrate 11 and the terminal protection cylinder 17 to the joint surface,
(3) Brazing method using gold brazing, silver brazing, etc.
(4) A method of bonding using an adhesive such as oxide glass,
Etc.

(7) Attaching an external terminal or the like A pin 19a with a tungsten screw is screwed into a bag hole 19 formed inside the terminal protection cylinder 17 via a brazing material 19c, and a Ni rod 19b with a brazing material is attached with a tungsten screw. It is preferable to screw into the pin (FIG. 6) and then heat to 900-1100 ° C.

  Further, a thermocouple 26 or the like as a temperature measuring element is inserted into the bottomed hole 14 formed in the bottom surface of the ceramic substrate 11, and the manufacture of the electrode embedding member 10 of the present invention is completed.

(Example 1)
(1) Aluminum nitride powder (manufactured by Tokuyama Corporation, average particle size 1.1 μm) 100 parts by weight, yttrium oxide (Y ₂ O ₃ : yttria, average particle size 0.4 μm) 4 parts by weight, acrylic binder 11.5 parts by weight, dispersant 0.5 Using a paste in which 53 parts by weight of an alcohol composed of 1 part by weight and 1-butanol and ethanol was mixed, molding was performed by a doctor blade method to produce a green sheet having a thickness of 0.47 mm used as a substrate.
(2) Next, after this green sheet was dried at 80 ° C. for 5 hours, 10 cylindrical through-holes with a diameter of 3.0 mm were formed radially inward from the outer periphery of the green sheet for forming the power supply terminals. It was formed by punching at equal intervals in the circumferential direction at a position of 33 mm (distance 132 mm from the center).
(3) 10000 parts by weight of tungsten carbide (WC-10 manufactured by Allied Material) particles having an average particle size of 1 μm, 1509 parts by weight of an acrylic binder (SA-545 manufactured by Mitsui Chemicals), and 175 parts by weight of a plasticizer (DOA manufactured by Kuroki Kasei) Then, 560 parts by weight of 1-butanol and 432 parts by weight of ethanol were mixed, and a tungsten carbide green sheet having a thickness of 65 μm ± 5 μm was produced by a doctor blade method. This tungsten carbide green sheet was dried in air at 25 ° C. for 48 hours to obtain a green sheet having a thickness of 55 μm ± 5 μm, and this green sheet was punched to form a tungsten carbide pattern sheet to be a heater electrode. .
(4) Mixing 100 parts by weight of tungsten carbide particles with an average particle diameter of 3 μm, 1.9 parts by weight of an acrylic binder, 3.7 parts by weight of α-terpineol solvent, and 0.2 parts by weight of a dispersant to prepare a conductor paste for an electrode for plasma generation. A tungsten carbide green sheet having a thickness of 65 μm ± 5 μm was manufactured by the doctor blade method. This tungsten carbide green sheet is dried in air at 25 ° C. for 48 hours to obtain a green sheet having a thickness of 55 μm ± 5 μm, and this green sheet is punched into a tungsten carbide pattern sheet to be used as an electrode for plasma generation. Formed.
(5) The through-hole portion formed in (2) above is filled with the same electrode paste as in (4) above, and dried in a dryer at 80 ° C. for 5 hours at a thickness of 0.47 mm. A disk-shaped power supply terminal having a diameter of 3.0 mm was obtained.
(6) The green sheet and the tungsten carbide pattern sheet after the treatments (1) to (5) were laminated, and pressure-bonded at 130 ° C. and a pressure of 8 MPa to form a laminate.
(7) Next, the obtained laminate was degreased in nitrogen gas at 600 ° C. for 5 hours and hot-pressed at 1840 ° C. under a pressure of 15 MPa for 6 hours to obtain a ceramic plate having a thickness of 18 mm. This was cut out into a 330 mm disk shape, and a ceramic plate having a through hole and a heater electrode with a thickness of 25 μm and a width of 10 mm and a plasma generating electrode with a thickness of 80 μm and an aperture ratio of 36% inside. .
(8) Then, a screw groove is formed on the side surface for fixing the bottomed hole for inserting the temperature measuring element by drilling and the electrode rod made of nickel on the surface of the obtained ceramic plate-like body A hole was formed.
(9) Blasting was performed so that the roughness of the wafer processing surface of the electrode embedding member manufactured by the steps (1) to (8) was 0.5 μm.
(10) Aluminum nitride powder (manufactured by Tokuyama Co., Ltd., average particle size 0.6 μm) is cylindrically formed by dry rubber pressing at a position surrounding the power supply terminal of the electrode embedding member manufactured by the steps (1) to (9). Formed into a mold, degreased in an oxidizing atmosphere at 600 ° C for 5 hours, and then fired in nitrogen gas at 1860 ° C for 6 hours (aluminum nitride columnar body (outer diameter 80 mm, inner diameter) 70 mm in length and 190 mm in length) were bonded in nitrogen gas by heating at 1850 ° C.
(11) The segment 1n was drilled to form a through-hole through which the lifter pin of the silicon wafer was inserted and a bottomed hole (diameter: 1.7 mm, depth: 10 mm) for embedding the thermocouple.
(12) A tungsten pin with an Au-Ni brazing material is fixed to the fixing hole in a fixing hole in which a screw groove is formed on the side surface for fixing the nickel electrode rod, and the tip is Au-Ni A nickel rod to which a brazing material was attached was screwed, and the nickel rod was brazed in a nitrogen atmosphere at 1030 ° C. for 28 minutes to obtain a plasma generating electrode-embedded member.

(Example 2)
(1) Aluminum nitride powder (manufactured by Tokuyama Corporation, average particle size 1.1 μm) 100 parts by weight, yttrium oxide (Y ₂ O ₃ : yttria, average particle size 0.4 μm) 4 parts by weight, acrylic binder 11.5 parts by weight, dispersant 0.5 Using a paste in which 53 parts by weight of an alcohol composed of 1 part by weight and 1-butanol and ethanol was mixed, molding was performed by a doctor blade method to produce a green sheet having a thickness of 0.47 mm used as a substrate.
(2) Next, after this green sheet was dried at 80 ° C. for 5 hours, 10 through-holes having a petal-like cross section with a diameter of 12.0 mm were formed on the inner side in the radial direction from the outer periphery of the green sheet. In the direction of 25 mm (distance 140 mm from the center), it was formed by punching at equal intervals in the circumferential direction.
(3) 10000 parts by weight of tungsten carbide (WC-10 manufactured by Allied Material) particles having an average particle size of 1 μm, 1509 parts by weight of an acrylic binder (SA-545 manufactured by Mitsui Chemicals), and 175 parts by weight of a plasticizer (DOA manufactured by Kuroki Kasei) Then, 560 parts by weight of 1-butanol and 432 parts by weight of ethanol were mixed, and a tungsten carbide green sheet having a thickness of 65 μm ± 5 μm was produced by a doctor blade method. This tungsten carbide green sheet was dried in air at 25 ° C. for 48 hours to obtain a green sheet having a thickness of 55 μm ± 5 μm, and this green sheet was punched to form a tungsten carbide pattern sheet to be a heater electrode. .
(4) Mixing 100 parts by weight of tungsten carbide particles with an average particle diameter of 3 μm, 1.9 parts by weight of an acrylic binder, 3.7 parts by weight of α-terpineol solvent, and 0.2 parts by weight of a dispersant to prepare a conductor paste for an electrode for plasma generation. A tungsten carbide green sheet having a thickness of 65 μm ± 5 μm was manufactured by the doctor blade method. This tungsten carbide green sheet is dried in air at 25 ° C. for 48 hours to obtain a green sheet having a thickness of 55 μm ± 5 μm, and this green sheet is punched into a tungsten carbide pattern sheet to be used as an electrode for plasma generation. Formed.
(5) Next, the conductive paste is applied to the inner wall of the through hole so that the through hole is not completely filled with the conductive paste so that the center portion is hollow (tubular). A cylindrical power supply terminal having a petal-shaped cross-section with a petal-shaped cross section having a thickness of 0.47 mm and a diameter of 3.0 mm, which is further dried with a dryer at 80 ° C. for 5 hours and then filled with an aluminum nitride paste in the cavity. did.
(6) The green sheet and the tungsten carbide pattern sheet after the treatments (1) to (5) were laminated, and pressure-bonded at 130 ° C. and a pressure of 8 MPa to form a laminate.
(7) Next, the obtained laminate was degreased in nitrogen gas at 600 ° C. for 5 hours and hot-pressed at 1840 ° C. under a pressure of 15 MPa for 6 hours to obtain a ceramic plate having a thickness of 18 mm. This was cut out into a 330 mm disk shape, and a ceramic plate having a through hole and a heater electrode with a thickness of 25 μm and a width of 10 mm and a plasma generating electrode with a thickness of 80 μm and an aperture ratio of 36% inside. .
(8) Then, a screw groove is formed on the side surface for fixing the bottomed hole for inserting the temperature measuring element by drilling and the electrode rod made of nickel on the surface of the obtained ceramic plate-like body A hole was formed.
(9) Blasting was performed so that the roughness of the wafer processing surface of the electrode embedding member manufactured by the steps (1) to (8) was Ra of 0.8 μm.
(10) Aluminum nitride powder (manufactured by Tokuyama Co., Ltd., average particle size 0.6 μm) is cylindrically formed by dry rubber pressing at a position surrounding the power supply terminal of the electrode embedding member manufactured by the steps (1) to (9). Formed into a mold, degreased in an oxidizing atmosphere at 600 ° C for 5 hours, and then fired in nitrogen gas at 1860 ° C for 6 hours (aluminum nitride columnar body (outer diameter 80 mm, inner diameter)
70 mm in length and 190 mm in length) were bonded in nitrogen gas by heating at 1850 ° C.
(11) The segment 1n was drilled to form a through-hole through which the lifter pin of the silicon wafer was inserted and a bottomed hole (diameter: 1.7 mm, depth: 10 mm) for embedding the thermocouple.
(12) A tungsten pin with an Au-Ni brazing material is fixed to the fixing hole in a fixing hole in which a screw groove is formed on the side surface for fixing the nickel electrode rod, and the tip is Au-Ni A nickel rod to which a brazing material was attached was screwed, and the nickel rod was brazed in a nitrogen atmosphere at 1030 ° C. for 28 minutes to obtain a plasma generating electrode-embedded member.

(Example 3)
(1) Aluminum nitride powder (manufactured by Tokuyama Corporation, average particle size 1.1 μm) 100 parts by weight, yttrium oxide (Y ₂ O ₃ : yttria, average particle size 0.4 μm) 4 parts by weight, acrylic binder 11.5 parts by weight, dispersant 0.5 Using a paste in which 53 parts by weight of an alcohol composed of 1 part by weight and 1-butanol and ethanol was mixed, molding was performed by a doctor blade method to produce a 0.47 mm thick green sheet as a substrate.
(2) Next, after this green sheet was dried at 80 ° C. for 5 hours, 10 star-shaped through-holes with a diameter of 3.0 mm were formed on the inner side in the radial direction from the outer periphery of the green sheet. In the direction of 15mm (distance from the center 150mm), it was formed by punching at equal intervals in the circumferential direction.
(3) 10000 parts by weight of tungsten carbide (WC-10 manufactured by Allied Material) particles having an average particle size of 1 μm, 1509 parts by weight of an acrylic binder (SA-545 manufactured by Mitsui Chemicals), and 175 parts by weight of a plasticizer (DOA manufactured by Kuroki Kasei) Then, 560 parts by weight of 1-butanol and 432 parts by weight of ethanol were mixed, and a tungsten carbide green sheet having a thickness of 65 μm ± 5 μm was produced by a doctor blade method. This tungsten carbide green sheet was dried in air at 25 ° C. for 48 hours to obtain a green sheet having a thickness of 55 μm ± 5 μm, and this green sheet was punched to form a tungsten carbide pattern sheet to be a heater electrode. .
(4) Mixing 100 parts by weight of tungsten carbide particles with an average particle diameter of 3 μm, 1.9 parts by weight of an acrylic binder, 3.7 parts by weight of α-terpineol solvent, and 0.2 parts by weight of a dispersant to prepare a conductor paste for an electrode for plasma generation. The tungsten carbide green sheet is dried in air at 25 ° C. for 48 hours to obtain a green sheet having a thickness of 55 μm ± 5 μm. The green sheet is punched to form a tungsten pattern sheet to be used as a plasma generating electrode. Formed.
(5) The through-hole portion formed in (2) above is filled with the same electrode paste as in (4) above, and dried in a dryer at 80 ° C. for 5 hours at a thickness of 0.47 mm. A power supply terminal having a star-shaped cross-section with a diameter of 3.0 mm was obtained.
(6) A green sheet and the tungsten carbide pattern sheet after the above treatments (1) to (5) were laminated and pressure-bonded at 130 ° C. and a pressure of 8 MPa to form a laminate.
(7) Next, the obtained laminate was degreased in nitrogen gas at 600 ° C. for 5 hours and hot-pressed at 1840 ° C. under a pressure of 15 MPa for 6 hours to obtain a ceramic plate having a thickness of 18 mm. This was cut out into a 330 mm disk shape, and a ceramic plate having a through hole and a heater electrode with a thickness of 25 μm and a width of 10 mm and a plasma generating electrode with a thickness of 80 μm and an aperture ratio of 36% inside. .
(8) Then, a screw groove is formed on the side surface for fixing the bottomed hole for inserting the temperature measuring element by drilling and the electrode rod made of nickel on the surface of the obtained ceramic plate-like body A hole was formed.
(9) Blasting was performed so that the roughness of the wafer processing surface of the electrode embedding member manufactured by the steps (1) to (8) was Ra of 0.8 μm.
(10) Aluminum nitride powder (manufactured by Tokuyama Co., Ltd., average particle size 0.6 μm) is cylindrically formed by dry rubber pressing at a position surrounding the power supply terminal of the electrode embedding member manufactured by the steps (1) to (9). Formed into a mold, degreased in an oxidizing atmosphere at 600 ° C for 5 hours, and then fired in nitrogen gas at 1860 ° C for 6 hours (aluminum nitride columnar body (outer diameter 80 mm, inner diameter)
70 mm in length and 190 mm in length) were bonded in nitrogen gas by heating at 1850 ° C.
(11) The segment 1n was drilled to form a through-hole through which the lifter pin of the silicon wafer was inserted and a bottomed hole (diameter: 1.7 mm, depth: 10 mm) for embedding the thermocouple.
(12) A tungsten pin with an Au-Ni brazing material is fixed to the fixing hole in a fixing hole in which a screw groove is formed on the side surface for fixing the nickel electrode rod, and the tip is Au-Ni A nickel rod to which a brazing material was attached was screwed, and the nickel rod was brazed in a nitrogen atmosphere at 1030 ° C. for 28 minutes to obtain a plasma generating electrode-embedded member.

Example 4
(1) Aluminum nitride powder (manufactured by Tokuyama Corporation, average particle size 1.1 μm) 100 parts by weight, yttrium oxide (Y ₂ O ₃ : yttria, average particle size 0.4 μm) 4 parts by weight, acrylic binder 11.5 parts by weight, dispersant 0.5 Using a paste in which 53 parts by weight of an alcohol composed of 1 part by weight and 1-butanol and ethanol was mixed, molding was performed by a doctor blade method to produce a green sheet having a thickness of 0.47 mm used as a substrate.
(2) Next, after this green sheet was dried at 80 ° C. for 5 hours, 10 through-holes having a petal-like cross section with a diameter of 12.0 mm were formed on the inner side in the radial direction from the outer periphery of the green sheet. Toward the surface by punching at equal intervals in the circumferential direction at a position of 8 mm (distance 157 mm from the center).
(3) 10000 parts by weight of tungsten carbide (WC-10 manufactured by Allied Material) particles having an average particle size of 1 μm, 1509 parts by weight of an acrylic binder (SA-545 manufactured by Mitsui Chemicals), and 175 parts by weight of a plasticizer (DOA manufactured by Kuroki Kasei) Then, 560 parts by weight of 1-butanol and 432 parts by weight of ethanol were mixed, and a tungsten carbide green sheet having a thickness of 65 μm ± 5 μm was produced by a doctor blade method. This tungsten carbide green sheet was dried in air at 25 ° C. for 48 hours to obtain a green sheet having a thickness of 55 μm ± 5 μm, and this green sheet was punched to form a tungsten carbide pattern sheet to be a heater electrode. .
(4) Mixing 100 parts by weight of tungsten carbide particles with an average particle diameter of 3 μm, 1.9 parts by weight of an acrylic binder, 3.7 parts by weight of α-terpineol solvent, and 0.2 parts by weight of a dispersant to prepare a conductor paste for an electrode for plasma generation. A tungsten carbide green sheet having a thickness of 65 μm ± 5 μm was manufactured by the doctor blade method. This tungsten carbide green sheet is dried in air at 25 ° C. for 48 hours to obtain a green sheet having a thickness of 55 μm ± 5 μm, and this green sheet is punched into a tungsten carbide pattern sheet to be used as an electrode for plasma generation. Formed.
(5) Next, the conductive paste is applied to the inner wall of the through hole so that the through hole is not completely filled with the conductive paste so that the center portion is hollow (tubular). A cylindrical power supply terminal having a petal-shaped cross-section with a petal-shaped cross section having a thickness of 0.47 mm and a diameter of 3.0 mm, which is further dried with a dryer at 80 ° C. for 5 hours and then filled with an aluminum nitride paste in the cavity. did.
(6) The green sheet and the tungsten carbide pattern sheet after the treatments (1) to (5) were laminated, and pressure-bonded at 130 ° C. and a pressure of 8 MPa to form a laminate.
(7) Next, the obtained laminate was degreased in nitrogen gas at 600 ° C. for 5 hours and hot-pressed at 1840 ° C. under a pressure of 15 MPa for 6 hours to obtain a ceramic plate having a thickness of 18 mm. This was cut out into a 330 mm disk shape, and a ceramic plate having a through hole and a heater electrode with a thickness of 25 μm and a width of 10 mm and a plasma generating electrode with a thickness of 80 μm and an aperture ratio of 36% inside. .
(8) Then, a screw groove is formed on the side surface for fixing the bottomed hole for inserting the temperature measuring element by drilling and the electrode rod made of nickel on the surface of the obtained ceramic plate-like body A hole was formed.
(9) Blasting was performed so that the roughness of the wafer processing surface of the electrode embedding member manufactured by the steps (1) to (8) was Ra of 0.8 μm.
(10) Aluminum nitride powder (manufactured by Tokuyama Co., Ltd., average particle size 0.6 μm) is cylindrically formed by dry rubber pressing at a position surrounding the power supply terminal of the electrode embedding member manufactured by the steps (1) to (9). Formed into a mold, degreased in an oxidizing atmosphere at 600 ° C for 5 hours, and then fired in nitrogen gas at 1860 ° C for 6 hours (aluminum nitride columnar body (outer diameter 80 mm, inner diameter)
70 mm in length and 190 mm in length) were bonded in nitrogen gas by heating at 1850 ° C.
(11) The segment 1n was drilled to form a through-hole through which the lifter pin of the silicon wafer was inserted and a bottomed hole (diameter: 1.7 mm, depth: 10 mm) for embedding the thermocouple.
(12) A tungsten pin with an Au-Ni brazing material is fixed to the fixing hole in a fixing hole in which a screw groove is formed on the side surface for fixing the nickel electrode rod, and the tip is Au-Ni A nickel rod to which a brazing material was attached was screwed, and the nickel rod was brazed in a nitrogen atmosphere at 1030 ° C. for 28 minutes to obtain a plasma generating electrode-embedded member.

(Comparative Example 1)
(1) Aluminum nitride powder (manufactured by Tokuyama Corporation, average particle size 1.1 μm) 100 parts by weight, yttrium oxide (Y ₂ O ₃ : yttria, average particle size 0.4 μm) 4 parts by weight, acrylic binder 11.5 parts by weight, dispersant 0.5 Using a paste in which 53 parts by weight of an alcohol composed of 1 part by weight and 1-butanol and ethanol was mixed, molding was performed by a doctor blade method to produce a 0.47 mm thick green sheet as a substrate.
(2) Next, after this green sheet was dried at 80 ° C. for 5 hours, 10 through-holes with a diameter of 3.0 mm were formed 115 mm from the outer periphery of the green sheet (50 mm from the center). ) At the position of).
(3) 10000 parts by weight of tungsten carbide (WC-10 manufactured by Allied Material) particles having an average particle size of 1 μm, 1509 parts by weight of an acrylic binder (SA-545 manufactured by Mitsui Chemicals), and 175 parts by weight of a plasticizer (DOA manufactured by Kuroki Kasei) Then, 560 parts by weight of 1-butanol and 432 parts by weight of ethanol were mixed, and a tungsten carbide green sheet having a thickness of 65 μm ± 5 μm was produced by a doctor blade method. This tungsten carbide green sheet was dried in air at 25 ° C. for 48 hours to obtain a green sheet having a thickness of 55 μm ± 5 μm, and this green sheet was punched to form a tungsten carbide pattern sheet to be a heater electrode. .
(4) A conductive paste for an electrode for plasma generation was prepared by mixing 100 parts by weight of tungsten carbide particles having an average particle size of 3 μm, 1.9 parts by weight of an acrylic binder, 3.7 parts by weight of α-terpineol solvent, and 0.2 parts by weight of a dispersant. . Furthermore, the conductor paste was filled in a portion to be a through hole for connecting an external terminal, and a cylindrical filling layer having a diameter of 3.0 mm and having no irregularities was formed to obtain a power feeding terminal.
(5) The green sheet and the tungsten carbide pattern sheet after the treatments (1) to (4) were laminated, and pressure-bonded at 130 ° C. and a pressure of 8 MPa to form a laminate.
(6) Next, the obtained laminate was degreased in nitrogen gas at 600 ° C. for 5 hours, and hot-pressed at 1840 ° C. and a pressure of 15 MPa for 6 hours to obtain a ceramic plate having a thickness of 18 mm. This was cut into a 330 mm disk shape, and a ceramic plate-like body having a heater electrode with a thickness of 25 μm and a width of 10 mm inside and a through hole was obtained.
(7) Fixing in which a screw groove is formed on a side surface for fixing a bottomed hole for inserting a temperature measuring element by drilling and a nickel electrode rod on the surface of the obtained ceramic plate-like body A hole was formed.
(8) Blasting was performed so that the roughness of the wafer processing surface of the electrode embedding member manufactured by the steps (1) to (7) was Ra of 0.9 μm.
(9) Aluminum nitride powder (manufactured by Tokuyama Corp., average particle size 0.6 μm) is formed into a cylindrical shape by a dry rubber press method on the electrode embedding member manufactured by the steps (1) to (8), and oxidized. Columnar made of aluminum nitride that is degreased at 600 ° C for 5 hours in an atmosphere and then fired in nitrogen gas at 1860 ° C for 6 hours (outer diameter 80 mm, inner diameter 70 mm, length 190 mm ) Was heated in nitrogen gas at 1850 ° C. for bonding.
(10) The segment 1n was drilled to form a through hole for inserting a lifter pin of a silicon wafer and a bottomed hole (diameter: 1.7 mm, depth: 10 mm) for embedding a thermocouple.
(11) A tungsten pin with an Au-Ni brazing material is fixed to the fixing hole in a fixing hole in which a screw groove is formed on the side surface for fixing the nickel electrode rod, and the tip is Au-Ni A nickel rod to which a brazing material was attached was screwed, and the nickel rod was brazed in a nitrogen atmosphere at 1030 ° C. for 28 minutes to obtain a plasma generating electrode-embedded member.

(Comparative Example 2)
(1) Aluminum nitride powder (manufactured by Tokuyama Corporation, average particle size 1.1 μm) 100 parts by weight, yttrium oxide (Y ₂ O ₃ : yttria, average particle size 0.4 μm) 4 parts by weight, acrylic binder 11.5 parts by weight, dispersant 0.5 Using a paste in which 53 parts by weight of alcohol composed of 1 part by weight and 1-butanol and ethanol were mixed, molding was performed by a doctor blade method to produce a green sheet having a thickness of 0.47 mm used as a substrate.
(2) Next, after this green sheet was dried at 80 ° C. for 5 hours, 10 through-holes with a diameter of 18.0 mm were formed 85 mm from the outer periphery of the green sheet (80 mm from the center). ) At the position of).
(3) 10000 parts by weight of tungsten carbide (WC-10 manufactured by Allied Material) particles having an average particle size of 1 μm, 1509 parts by weight of an acrylic binder (SA-545 manufactured by Mitsui Chemicals), and 175 parts by weight of a plasticizer (DOA manufactured by Kuroki Kasei) Then, 560 parts by weight of 1-butanol and 432 parts by weight of ethanol were mixed, and a tungsten carbide green sheet having a thickness of 65 μm ± 5 μm was produced by a doctor blade method. This tungsten carbide green sheet was dried in air at 25 ° C. for 48 hours to obtain a green sheet having a thickness of 55 μm ± 5 μm, and this green sheet was punched to form a tungsten carbide pattern sheet to be a heater electrode. .
(4) A conductive paste for an electrode for plasma generation was prepared by mixing 100 parts by weight of tungsten carbide particles having an average particle size of 3 μm, 1.9 parts by weight of an acrylic binder, 3.7 parts by weight of α-terpineol solvent, and 0.2 parts by weight of a dispersant. . Furthermore, a conductive paste was filled in a portion serving as a through hole for connecting an external terminal to obtain a power supply terminal having a cylindrical shape with a diameter of 18.0 mm and having no unevenness.
(5) The green sheet and the tungsten carbide pattern sheet after the treatments (1) to (4) were laminated, and pressure-bonded at 130 ° C. and a pressure of 8 MPa to form a laminate.
(6) Next, the obtained laminate was degreased in nitrogen gas at 600 ° C. for 5 hours, and hot-pressed at 1840 ° C. and a pressure of 15 MPa for 6 hours to obtain a ceramic plate having a thickness of 18 mm. This was cut into a 330 mm disk shape, and a ceramic plate-like body having a heater electrode with a thickness of 25 μm and a width of 10 mm inside and a through hole was obtained.
(7) Fixing in which a screw groove is formed on a side surface for fixing a bottomed hole for inserting a temperature measuring element by drilling and a nickel electrode rod on the surface of the obtained ceramic plate-like body A hole was formed.
(8) Blasting was performed so that the roughness of the wafer processing surface of the electrode embedding member manufactured by the steps (1) to (7) was Ra of 0.8 μm.
(9) Aluminum nitride powder (manufactured by Tokuyama Corp., average particle size 0.6 μm) is formed into a cylindrical shape by a dry rubber press method on the electrode embedding member manufactured by the steps (1) to (8), and oxidized. Columnar made of aluminum nitride that is degreased at 600 ° C for 5 hours in an atmosphere and then fired in nitrogen gas at 1860 ° C for 6 hours (outer diameter 80 mm, inner diameter 70 mm, length 190 mm ) Was heated in nitrogen gas at 1850 ° C. for bonding.
(10) The segment 1n was drilled to form a through hole for inserting a lifter pin of a silicon wafer and a bottomed hole (diameter: 1.7 mm, depth: 10 mm) for embedding a thermocouple.
(11) A tungsten pin with an Au-Ni brazing material is fixed to the fixing hole in a fixing hole in which a screw groove is formed on the side surface for fixing the nickel electrode rod, and the tip is Au-Ni A nickel rod to which a brazing material was attached was screwed, and the nickel rod was brazed in a nitrogen atmosphere at 1030 ° C. for 28 minutes to obtain a plasma generating electrode-embedded member.

(Comparative Example 3)
(1) Aluminum nitride powder (manufactured by Tokuyama Corporation, average particle size 1.1 μm) 100 parts by weight, yttrium oxide (Y ₂ O ₃ : yttria, average particle size 0.4 μm) 4 parts by weight, acrylic binder 11.5 parts by weight, dispersant 0.5 Using a paste in which 53 parts by weight of an alcohol composed of 1 part by weight and 1-butanol and ethanol was mixed, molding was performed by a doctor blade method to produce a green sheet having a thickness of 0.47 mm.
(2) Next, after drying this green sheet at 80 ° C. for 5 hours, in order to form a through hole for forming the power supply terminal, the distance from the outer periphery of the green sheet to 65 mm (100 mm from the center) Radially, 10 circular through holes with a diameter of 3 mm were formed by punching.
(3) 10000 parts by weight of tungsten carbide (WC-10 manufactured by Allied Material) particles having an average particle diameter of 1 μm, 1509 parts by weight of an acrylic binder (SA-545 manufactured by Mitsui Chemicals), and 175 parts by weight of a plasticizer (DOA manufactured by Kuroki Kasei) Then, 560 parts by weight of 1-butanol and 432 parts by weight of ethanol were mixed, and a tungsten carbide green sheet having a thickness of 65 μm ± 5 μm was produced by a doctor blade method. This was dried in air at 25 ° C. for 48 hours to obtain a green sheet having a thickness of 55 μm ± 5 μm, and this green sheet was punched to form a tungsten carbide pattern sheet to be a heater electrode.
(4) 100 parts by weight of tungsten particles having an average particle diameter of 3 μm, 1.9 parts by weight of an acrylic binder, 3.7 parts by weight of α-terpineol solvent, and 0.2 parts by weight of a dispersant were mixed to prepare a conductor paste for plasma generating electrode. Further, a portion serving as a through hole for connecting an external terminal was filled with a conductive paste, and a filling layer was formed to form a power supply terminal.
(5) The green sheets of (1) to (4) after the above treatment and the tungsten carbide pattern sheet were laminated and pressure-bonded at 130 ° C. and a pressure of 8 MPa to form a laminate.
(6) Next, the obtained laminate was degreased in nitrogen gas at 600 ° C. for 5 hours, and hot pressed at 1840 ° C. and a pressure of 15 MPa for 6 hours to obtain a ceramic plate having a thickness of 18 mm. This was cut into a 330 mm disk shape, and a ceramic plate-like body having a heater electrode with a thickness of 25 μm and a width of 10 mm inside and a through hole was obtained.
(7) Fixing in which a screw groove is formed on a side surface for fixing a bottomed hole for inserting a temperature measuring element by drilling and a nickel electrode rod on the surface of the obtained ceramic plate-like body A hole was formed.
(8) Blasting was performed so that the roughness of the wafer processing surface of the electrode embedding member manufactured by the steps (1) to (7), that is, the ceramic heater was 0.5 μm.
(9) To the ceramic heater manufactured by the steps (1) to (8), aluminum nitride powder (manufactured by Tokuyama Corporation, average particle size 0.6 μm) is formed into a cylindrical shape by a dry rubber press method, and an oxidizing atmosphere, A columnar body made of aluminum nitride (outer diameter 80 mm, inner diameter 70 mm, length 190 mm) formed by degreasing at 600 ° C for 5 hours and then firing in nitrogen gas at 1860 ° C for 6 hours Bonding was performed by heating at 1850 ° C. in nitrogen gas.
(10) The segment 1n was drilled to form a through hole for inserting a lifter pin of a silicon wafer and a bottomed hole (diameter: 1.7 mm, depth: 10 mm) for embedding a thermocouple.
(12) A tungsten pin with an Au-Ni brazing material is fixed to the fixing hole in a fixing hole in which a screw groove is formed on the side surface for fixing the nickel electrode rod, and the tip is Au-Ni A nickel rod with a brazing material was screwed in, and the nickel rod was brazed in a nitrogen atmosphere at 1030 ° C. for 28 minutes.

Discussion of Examples and Comparative Examples Table 1 shows the positions of the power supply terminals installed on the bottom surface of the plasma generating electrode and the cycle test results. From the results shown in the table, it was found that durability was excellent when the power supply terminal was installed at a position equivalent to 132 mm or more from the center of the ceramic substrate, that is, within 20% of the outer periphery of the ceramic substrate with a diameter of 330 mm. .
Therefore, according to the electrode embedding member for a plasma generator according to the present invention, even when the ceramic substrate is used for a long time at a high temperature, heat generation at the power supply terminals installed on the bottom surfaces of the various electrodes embedded in the substrate is small and durable. It is possible to provide an electrode embedded member for a plasma generator that is excellent in performance and can maintain quality in a stable state for a long period of time.

  The electrode embedding member according to the present invention is used for a thin film forming apparatus such as a CVD apparatus for forming a thin film on a semiconductor wafer and a dry etching apparatus in the field of manufacturing a semiconductor.

It is a fragmentary sectional view of the electrode embedding member for plasma generators of the present invention. It is a top view which shows typically an example of the electrode for plasma generation. It is sectional drawing which shows the example which embedded the electrode for plasma generation in the multilayer in the board | substrate. It is a top view which shows typically the other example of the electrode for plasma generation. (A)-(c) is sectional drawing which shows an example of the manufacturing method of the electrode embedding member for plasma generators of this invention. It is an expanded sectional view of an external terminal attachment part. (A)-(d) is sectional drawing which shows the shape of the junction part of the shape of an electric power feeding terminal and the electrode for plasma generation.

Explanation of symbols

10, 30, 40 Electrode embedding member 11, 31, 41 Ceramic substrate 11a Heating surface 11b Bottom surface 11c Emboss 12, 32, 42 Heater electrodes 13, 113 Through hole 14 Bottomed hole 15 Through hole 17 Terminal protection cylinder 19 Bag hole 23 External Terminal 24 Conductive wire 26 Lead wire 110 Green sheet 120 Motor electrode pattern layer 130 Conductive paste filling layer 180 Side temperature element

Claims (3)

A plasma characterized in that an electrode for plasma generation is embedded in a ceramic substrate and a power supply terminal is connected to one surface of the electrode, and the power supply terminal is disposed near the outer periphery of the ceramic substrate. Electrode burying member for generator. 2. The electrode embedding member for a plasma generator according to claim 1, wherein the power supply terminal is disposed in a region corresponding to 20% of the diameter in the radial direction from the outer peripheral edge of the ceramic substrate. 3. The electrode embedding member for a plasma generating apparatus according to claim 1, wherein the plasma generating electrode is formed of conductive carbide ceramics or conductive nitride ceramics.

Images