JP3649378B2 - Plasma processing apparatus and plasma processing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plasma processing apparatus and a plasma processing method for performing film formation, processing, surface treatment, and the like on a substrate, and in particular, uniform, high quality, and high speed even for a large area substrate. The present invention relates to a plasma processing apparatus and a plasma processing method capable of performing film formation, processing, surface treatment, and the like.
[0002]
[Prior art]
In plasma processing such as film formation, processing, and surface processing, it is desired to make the plasma processing uniform within the substrate surface, to improve the quality of the plasma processing surface, and to increase the plasma processing speed. In particular, in the manufacturing process of a thin-film Si solar cell that has attracted attention in recent years, an amorphous or microcrystalline Si thin film is formed on a glass substrate or a sheet-like substrate by a plasma CVD (Chemical Vapor Deposition) method or the like. The demand for uniform and high quality of the Si thin film and the improvement of the deposition rate is very severe. In addition to this, the recent increase in substrate size has made the above requirements even more severe. Below, the prior art for meeting the said request | requirement is demonstrated.
[0003]
(1) Uniform plasma treatment for large area substrates
In order to meet this demand, plasma processing gas is uniformly supplied to the plasma space to generate a small plasma that can maintain a uniform discharge state, and the small plasma and the substrate are relatively moved. It is effective to perform the plasma treatment on the entire surface of the substrate by moving it. For example, a technique is known in which plasma processing is performed while moving the substrate in the longitudinal direction using a narrow electrode such that the length of the plasma generating portion in the longitudinal direction of the substrate is shorter than the length of the substrate in that direction. It has been. Conventional techniques based on this viewpoint are disclosed in, for example, Japanese Patent Laid-Open Nos. 6-252071, 8-277471, 2589599, and 2667665.
[0004]
(2) Improvement of plasma processing surface quality for large area substrates
In order to meet this requirement, it is necessary to quickly remove the reaction product from the plasma treatment so that it does not stay and adhere to the substrate. For this purpose, as in the method {circle around (1)} above, it is effective to use an electrode that generates a small-sized plasma and to efficiently exhaust the plasma-treated gas in the immediate vicinity of the plasma space. Conventional techniques based on this viewpoint are disclosed in, for example, Japanese Patent Application Laid-Open Nos. 5-343338 and 2558999. Furthermore, it is important to exhaust the plasma-treated gas from the plasma space at a high speed, but the high-speed exhaust is not particularly described in the above publication. The importance of reducing the size of the plasma space and arranging the plasma-treated gas at high speed can be understood from the fact that the gas replacement time t in the plasma space is expressed by the following equation.
[0005]
t = V / Q (V: volume of plasma space, Q: flow rate of plasma processing gas)
[0006]
(3) Increase in plasma processing speed
(3) -a. Method 1 (Supplying large flow rate of plasma processing gas)
In order to increase the plasma processing speed, it is necessary to supply the plasma processing gas to the plasma space at a large flow rate corresponding to the processing speed. For this purpose, a cover body is provided so as to surround the pair of electrodes, and a large flow rate from the gas inlet port to the gas exhaust port through the plasma space by the gas inlet port and the gas exhaust port provided in the cover body. It is effective to form a high-speed gas flow. According to this method, since the gas flow is regulated by the cover body, leakage of the gas flow to the outside of the plasma space can be reduced, and a high-speed gas flow having a large flow rate can be formed. Conventional techniques based on this viewpoint include, for example, Japanese Patent Application Laid-Open Nos. 62-94922, 62-172146, 1-309975, 6-248457, and Japanese Patent Publication No. 7-100787. Etc. are disclosed.
[0007]
(3) -b. Method 2 (High pressure of plasma processing gas)
In order to increase the speed of the plasma processing, it is effective to increase the partial pressure of the reaction gas in the plasma processing gas in the plasma space in combination with the method 1 of (3) -a. Note that the reactive gas refers to a gas that actually contributes to the plasma treatment in distinction from the dilution gas. This technique is effective for increasing the processing speed, but it becomes difficult to stably generate plasma when the partial pressure of the reaction gas is increased. Therefore, in Japanese Patent Publication No. 6-60412, Japanese Patent No. 2700197 and Japanese Patent Laid-Open No. 6-299358, by diluting a high partial pressure reaction gas with a large amount of inert gas, There has been disclosed a technique for generating stable plasma even when the partial pressure of the reaction gas is increased, that is, even under a high-pressure plasma processing gas atmosphere. According to the methods of these publications, since a large amount of inert gas is added to the reaction gas, the plasma can be stably maintained even if the partial pressure of the reaction gas in the chamber is increased, and the processing speed can be improved. it can. However, in this method, since the pressure of the plasma processing gas in the chamber is set to a high pressure, plasma cannot be stably generated unless the distance between the pair of electrodes is narrowed. That is, in order to stably generate plasma at a high pressure, it is necessary to narrow the distance between the pair of electrodes. However, when the distance between the electrodes is narrowed, it is difficult to stably supply a large flow rate of the plasma processing gas between the electrodes due to friction loss of the gas flow.
[0008]
Hereinafter, a specific plasma processing apparatus capable of satisfying each of the above-mentioned (1) to (3) or two of the requirements will be described based on the conventional method.
[0009]
(A) Configuration 1 based on the prior art (a plasma processing apparatus that satisfies the requirements of (1) and (2) above)
As a plasma processing apparatus that satisfies the above requirements (1) and (2), for example, a configuration in which the contents disclosed in Japanese Patent No. 2667665 and the contents disclosed in Japanese Patent Laid-Open No. 5-343338 are combined. Conceivable. A plasma processing apparatus based on this viewpoint is shown in FIG.
[0010]
In FIG. 17, 501 is a chamber, 502 is a first electrode facing the substrate 550, 503 is a second electrode on which the substrate 550 is mounted, 504 is a gas inlet for introducing a plasma processing gas into the plasma space, and 505 is plasma. It is a gas exhaust port for exhausting the treated gas.
[0011]
In this plasma processing apparatus, when a plasma processing gas is introduced into the chamber 501 from the gas inlet 504 and a high frequency voltage is applied between the first electrode 502 and the second electrode 503, plasma based on the plasma processing gas is obtained. P is generated. A portion of the substrate 550 facing the first electrode 502 is plasma-treated by the action of the plasma P. Then, the plasma-treated gas is exhausted from the gas exhaust port 505. Here, the length of the plasma P in the X direction in the figure is shorter than the length of the substrate 550 in that direction, but by moving the second electrode 503 in the X direction, Plasma treatment is performed.
[0012]
Since the plasma P generated in the plasma processing apparatus is small in size, the plasma processing gas can be supplied uniformly to the plasma space, and a uniform discharge state can be maintained. That is, the plasma treatment can be performed uniformly on the portion facing the small-sized plasma P. Since the substrate 550 moves to face the plasma P with good uniformity, uniform plasma processing can be performed even on a large-area substrate. Further, the plasma P has a small size (volume of the plasma space), and furthermore, the gas after the plasma treatment is exhausted by the gas exhaust port 505 provided in the immediate vicinity, so that the time for which the reaction product stays in the plasma space is increased. Short and high quality plasma processing can be achieved.
[0013]
(B) Configuration 2 based on the prior art (plasma processing apparatus that satisfies the requirements of (3) above)
The contents disclosed in Japanese Patent Laid-Open No. 6-248457 as a plasma processing apparatus that satisfies the requirement (3) will be described with reference to FIG. The contents disclosed in this publication are based on the method 1 of the above (3) -a, and it is difficult to achieve compatibility with the method 2 of the above (3) -b. This point will be discussed later.
[The invention is solved]
This is explained in [Problems to be solved].
[0014]
In FIG. 18A, 601 is a chamber, 602 is a first electrode facing the substrate 650, 603 is a second electrode on which the substrate 650 is mounted, 604 is a gas inlet for introducing a plasma processing gas into the plasma space, Reference numeral 605 denotes a gas exhaust port for exhausting the plasma-treated gas. Reference numerals 606 and 607 respectively denote a gas supply unit and a gas exhaust unit provided to face each other with a space 611 between the first electrode 602 and the second electrode 603 interposed therebetween. The gas supply means 606 is provided with a number of jet outlets 608, and the gas exhaust means 607 is provided with a number of suction ports 609. Further, as shown in FIG. 18B, which is a cross-sectional view seen from a direction orthogonal to FIG. 18A, a partition plate 610 made of an insulator is raised at the edge of the second electrode 603. Is formed.
[0015]
In this plasma processing apparatus, a space 611 between the first electrode 602 and the second electrode 603 is partitioned in a box shape by a gas supply unit 606, a gas exhaust unit 607, and a partition plate 610. For this reason, the plasma processing gas introduced from the gas introduction port 604 can be stably supplied from the jet outlet 608 of the gas supply means 606 to the box-shaped space 611 at a large flow rate. The plasma P generated by applying a high frequency voltage between the first electrode 602 and the second electrode 603 can be confined in the box-shaped space 611. Further, the plasma-treated gas can be exhausted from the box-shaped space 611 through the suction port 609 of the gas exhaust means 607 at high speed.
[0016]
According to this configuration, since the plasma processing gas flows stably in the box-shaped space 611 without leaking to the region other than the box-shaped space portion 611, a large flow rate of the plasma processing gas is stably supplied to the plasma space. The film formation rate can be increased by supplying the film. Further, the gas after the plasma treatment can be exhausted at a high speed. However, in this case, since the plasma faces the entire surface of the substrate and its size is large, the residence time of the reaction product by the plasma treatment is not necessarily short. This can be understood from the fact that the gas replacement time t in the plasma space is expressed by the following equation.
[0017]
t = V / Q (V: volume of plasma space, Q: flow rate of plasma processing gas)
[0018]
[Problems to be solved by the invention]
Any of the above-mentioned conventional techniques can satisfy each of the above-mentioned (1) to (3) or two of the requirements, but satisfy all the requirements of (1) to (3). I couldn't. Below, the problems of the prior art will be specifically described.
[0019]
(A) Regarding the problem of configuration 1 above
The configuration of the plasma processing apparatus shown in FIG. 17 is particularly effective for achieving uniform plasma processing within the substrate surface and improving the quality of the plasma processing surface for a large-area substrate.
[0020]
However, there is a difficulty in further increasing the plasma processing speed. That is, in order to perform high-speed processing, it is necessary to supply a plasma flow gas having a flow rate sufficient to meet the processing speed to the plasma space. However, the plasma processing apparatus shown in FIG. It is difficult to supply. In FIG. 17, the desired gas flow path for the plasma processing gas is a path from the gas inlet 504 to the plasma space P to the gas exhaust 505, as indicated by FJ in the figure. However, in this flow path FJ, since the streamline changes abruptly, the conductance is small and it is difficult to supply a large flow rate gas. Furthermore, a gas flow that branches in a direction other than the desired flow path is also generated. Even if a large flow rate of gas is flowed, the flow is disturbed due to a sudden change in streamlines in the flow path. This causes non-uniformity of the plasma processing and quality degradation of the plasma processing surface, and the original effect is lost. This problem becomes more prominent when the pressure of the plasma space is further increased (method 2 of (3) -b above) in order to increase the processing speed. This is mainly due to the fact that the distance between the pair of electrodes must be narrowed in order to increase the pressure in the plasma space. That is, since the distance between the pair of electrodes is narrow, the conductance of the gas flow flowing between the electrodes is small, and it becomes difficult to stably supply a large flow rate of the plasma processing gas to the plasma space. Therefore, with this configuration, the requests (1) and (2) and the request (3) cannot be satisfied at the same time.
[0021]
(B) Regarding the problem of configuration 2 above
In the configuration of the plasma processing apparatus shown in FIG. 18, the cover for restricting the gas flow path in the plasma space is constituted by the gas supply means 606, the gas exhaust means 607, and the partition plate 610. Can be stably supplied to the plasma space at a high flow rate without leaking to a region other than the plasma space.
[0022]
However, since this cover completely surrounds the space 611 between the first electrode 602 and the second electrode 603, this technique is configured to move the substrate with respect to a small-sized plasma (the above-described configuration 1). ) Is not applicable. That is, the substrate cannot be moved in the geometrical arrangement of the configuration of FIG. Therefore, in this configuration, even though the requirement (3) can be satisfied, the requirements (1) and (2) cannot be satisfied. Further, when the plasma space is increased in pressure to increase the processing speed (method 2 of (3) -b above) and the distance between the pair of electrodes is narrowed, implementation of this configuration becomes difficult. The reason is that it is difficult to stably supply the plasma processing gas at a large flow rate over a long distance corresponding to the substrate size with respect to a narrow electrode interval in view of loss of gas flow.
[0023]
The present invention has been made to solve the above-described problems of the prior art, and in plasma processing such as film formation, processing, and surface treatment, a large flow rate can be achieved while moving a substrate with respect to a small-size plasma. The plasma processing gas is stably supplied to the plasma space and the reaction products are removed quickly to simultaneously satisfy the three requirements of high processing speed, uniform plasma processing, and high quality plasma processing surface. Furthermore, it aims at providing the plasma processing apparatus and plasma processing method which can respond also to a large sized substrate and a sheet-like board | substrate.
[0024]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention achieves the progressive effect of simultaneously satisfying the above three requirements that cannot be achieved by simply combining them while incorporating the conventional technical idea by a new configuration. .
[0025]
In the plasma processing apparatus of the present invention, a second electrode on which a first electrode and a substrate are mounted is disposed in a chamber having a first gas inlet and a first gas outlet, and at least a part of the first electrode A part of the second electrode is disposed opposite to the first space and only through the substrate, and a plasma processing gas is introduced into the first space from the first gas inlet. By applying a high frequency voltage between the first electrode and the second electrode, generating plasma in at least a part of the first space, and further moving the second electrode on which the substrate is mounted A plasma processing apparatus for performing plasma processing on the substrate, the communication introduction port communicating with the first gas introduction port, the communication exhaust port communicating with the first gas exhaust port, and an opening in the first space The first opening and the first opening in the vicinity of the first opening; A cover body having an electrode or a second electrode facing portion opposed to the substrate across a second space, the cover body not contacting the second electrode and the substrate, the first electrode, and Together with the second electrode or the substrate, a main gas flow path of the plasma processing gas is formed from the communication introduction port through the first space to the communication exhaust port, and the plasma flowing through the main gas flow channel The first electrode, the second electrode, and the cover body are arranged so that a rapid change is not applied to the flow line of the processing gas, thereby achieving the above object.
[0026]
The conductance of the flow from the first space toward the communication exhaust port in the main gas flow path is larger than the conductance of the flow from the first space to the second space other than the main gas flow path. Thus, it is preferable that the first electrode, the second electrode, and the cover body are arranged.
[0027]
The chamber further includes a second gas introduction port, and a gas having the same component as the plasma processing gas or an inert gas is introduced into the chamber from the second gas introduction port, and the chamber other than the main gas flow path The pressure in the region may be maintained at a pressure higher than the pressure in the main gas flow path.
[0028]
In the portion where the plasma is generated in the first space, the flow line of the plasma processing gas flowing through the main gas flow path is in a direction substantially along the substrate surface, the first electrode, Two electrodes and the cover body may be arranged.
[0029]
The first electrode may have a curved surface shape at least in the first space.
[0030]
At a substantially central portion in the width direction of the main gas flow path, a streamline of the plasma processing gas flowing through the main gas flow path is substantially U-shaped over the communication introduction port, the first space, and the communication exhaust port. The first electrode, the second electrode, and the cover body may be arranged so as to have a shape.
[0031]
The first electrode, the second electrode, and the cover body are arranged such that the width of the main gas flow path is minimized at the substantially U-shaped tip, and the width of the main gas flow path is minimized. Plasma may be generated in the vicinity of the portion.
[0032]
At a substantially central portion in the width direction of the main gas flow path, a streamline of the plasma processing gas flowing through the main gas flow path extends substantially linearly from the communication introduction port, the first space, and the communication exhaust port. The first electrode, the second electrode, and the cover body may be arranged so that
[0033]
The second electrode may have a cylindrical shape and be rotatable about a central axis thereof.
[0034]
A sheet-like substrate may be mounted as the substrate, and the sheet-like substrate may be movable while closely contacting the second electrode by rotation of the second electrode.
[0035]
The first electrode has a curved portion at least in the first space, and the radius of curvature of the curved portion of the first electrode and the radius of the cylindrical second electrode are substantially the same, and the first electrode The tip of the curved portion and the tip of the cylindrical second electrode are substantially opposed to each other, and the width of the main gas flow path is such that the tip of the first electrode and the tip of the second electrode The first electrode, the second electrode, and the cover body are arranged so as to be minimized at the portion facing the portion, and plasma is generated in the vicinity of the portion facing the width of the main gas channel being minimized. You may let them.
[0036]
The plasma processing method of the present invention performs plasma processing on a substrate using the plasma processing apparatus of the present invention, thereby achieving the above object.
[0037]
The operation of the present invention will be described below.
[0038]
In the present invention, a small-size plasma is generated in the first space, which is the facing portion between at least a part of the first electrode and a part of the second electrode, and the second electrode (and the In a plasma processing apparatus capable of performing uniform plasma processing on the entire surface of the substrate by moving the substrate mounted thereon, the first electrode and the cover that constitutes the main gas flow path together with the second electrode or the substrate are provided. . At this time, the first electrode, the first electrode, and the second electrode are arranged so that a rapid change is not applied to the flow line of the main gas flow path of the plasma processing gas from the communication introduction port of the cover body through the first space to the communication exhaust port of the cover body. Two electrodes and a cover body are arranged. This reduces the loss of the main gas flow path, increases the conductance, stably supplies a large flow rate of plasma processing gas to the plasma region, and at the same time delivers the plasma-treated gas from the communication outlet of the cover body at high speed. It is possible to exhaust. The cover body is not in contact with the second electrode and the substrate in order to move the second electrode, and is opposed to the second electrode or the substrate with a second space in the vicinity of the first opening. But the conductance of the flow from the first space toward the communication exhaust port in the main gas flow path is the flow conductance other than the main gas flow path from the first space to the second space. Since the first electrode, the second electrode, and the cover body are arranged so as to be larger than the gas flow, it is possible to suppress the leakage of gas to other than the main gas flow path and to stably generate a plasma with a large flow rate. While being supplied to the space, the plasma-treated gas can be exhausted at high speed from the communication exhaust port of the cover body without retaining the gas.
[0039]
Furthermore, by introducing a gas having the same component as the plasma processing gas or an inert gas into the chamber from the second gas inlet, the pressure in the region other than the main gas channel is higher than the pressure in the main gas channel. By maintaining the pressure, leakage of the plasma processing gas from the main gas channel to the outside of the main gas channel can be suppressed.
[0040]
In the portion where the plasma in the first space is generated, the first electrode, the second electrode, and the cover body are arranged so that the stream line of the plasma processing gas flowing through the main gas flow path is substantially along the substrate surface. If arranged, the loss of gas flow is small in the plasma generation region, and the flow is stabilized.
[0041]
For example, as shown in a first embodiment to be described later, at a substantially central portion in the width direction of the main gas channel, the stream line of the plasma processing gas flowing through the main gas channel is connected to the communication inlet of the cover body, the first If the first electrode, the second electrode, and the cover body are arranged so as to be substantially U-shaped over the space and the communication exhaust port, a rapid change is not applied to the streamline of the main gas flow path of the plasma processing gas. It is possible to In this case, even if the cover body is located above without contacting the substrate, the plasma processing gas is supplied from the first opening to the obliquely downward substrate. And since the gas after a plasma process flows and exhausts in the diagonally upward direction of the direction which leaves | separates from a board | substrate, it is suppressed that a reaction product adheres to a board | substrate. Furthermore, if the first electrode, the second electrode, and the cover body are arranged so that the width of the main gas flow path is minimized at the end of the substantially U-shaped bent portion, the width of the minimum width portion is very narrow. However, since such a narrow channel is provided only in a part of the main gas channel, the friction loss of the gas flow is greatly reduced. If plasma is generated in the vicinity of the portion where the width of the main gas flow path is minimized, it is possible to generate plasma under high pressure while stably flowing a large flow rate of plasma processing gas.
[0042]
Alternatively, as shown in a second embodiment to be described later, at a substantially central portion in the width direction of the main gas channel, a stream line of the plasma processing gas flowing through the main gas channel is connected to the communication inlet, the first space, and Even if the first electrode, the second electrode, and the cover body are arranged so as to be substantially straight over the communication exhaust port, a sudden change is not applied to the streamline of the main gas flow path of the plasma processing gas. Is possible.
[0043]
Furthermore, the second electrode may have a cylindrical shape and can be rotated around its central axis. The sheet-like substrate can be mounted on the second electrode, and the sheet-like substrate can be moved while being in close contact with the second electrode by the rotation of the second electrode.
[0044]
In this case, a curved surface portion of the first electrode is formed at least in the first space, the radius of curvature of the curved surface portion of the first electrode is substantially the same as the radius of the cylindrical second electrode, and the curved surface of the first electrode is formed. A small-sized plasma can be generated by substantially opposing the tip of the shape portion and the tip of the cylindrical second electrode.
[0045]
Furthermore, if the first electrode, the second electrode, and the cover body are arranged so that the main gas flow path has a substantially symmetrical shape with respect to the center line in the width direction, the main gas flow path of the plasma processing gas is further increased. It is possible to prevent a sudden change in the streamline. Further, if the width of the main gas flow path is minimized at the facing portion between the front end portion of the first electrode and the front end portion of the second electrode, and plasma is generated in the vicinity thereof, it is possible for stable high flow rate plasma processing. Plasma can be generated under high pressure while flowing gas.
[0046]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
[0047]
(First embodiment)
FIG. 1 is a cross-sectional view showing a schematic configuration of the plasma processing apparatus 100 of the present embodiment, FIG. 2 is a perspective view showing a main part of the plasma processing apparatus 100, and FIG. 3 shows a cross section in a plane PL1 of FIG. 4 is a cross-sectional view of the plane PL2 in FIG. 2, FIG. 5 is an exploded perspective view of each part of FIG. 3, and FIG. 6 is a main gas flow path FR in the plasma processing apparatus 100. FIG. Hereinafter, the plasma processing apparatus and the plasma processing method thereof according to the present embodiment will be described with reference to FIGS.
[0048]
(A) Components of the plasma processing apparatus 100
Hereinafter, components of the plasma processing apparatus 100 will be described mainly with reference to FIG.
[0049]
In FIG. 1, reference numeral 1 denotes a chamber, and a first gas introduction port 4 and a first gas exhaust port 5 are provided on a wall surface of the chamber. The first gas introduction port 4 is connected to a first gas supply unit 6 that supplies a plasma processing gas by a pipe 8, and the first gas exhaust port 5 is a first gas exhaust unit 7 that exhausts the plasma-treated gas. Are connected by a pipe 9. Further, as shown in FIG. 1, a second gas introduction port 10 and a second gas exhaust port 11 are provided on the wall surface of the chamber 1 and are connected to a second gas supply unit 12 and a second gas exhaust unit 13, respectively. Is preferred.
[0050]
Reference numeral 2 denotes a first electrode facing the substrate 50, and 3 denotes a flat plate-like second electrode on which the substrate 50 is mounted. The second electrode 3 is grounded and can be moved in the X direction in the figure by a drive mechanism (not shown). The first electrode 2 has a curved surface shape 2a in at least an opening (first opening) 25 of a cover body 23 (first cover body 21) described later. In the present embodiment, the cross-sectional shape of the first electrode 2 is a semicircular shape. For example, an arc-shaped cross section having a central angle of 180 ° or less may be used, or an arbitrary curved surface having a plurality of curvatures may be used. In the first opening 25 of the first cover body 21, the first electrode 2 and the second electrode 3 are opposed to each other with only the substrate 50 across the space (first space) SC. The tip 2at of the curved surface 2a of the first electrode 2 faces the substrate 50 with a gap G1 therebetween. In the vicinity of the tip portion 2at, a small-sized plasma P as shown in FIG.
[0051]
The 1st electrode 2 is being fixed to the cover body 23 (2nd cover body 22) which consists of an insulator in the back surface 2b. The 2nd cover body 22 has the groove part (or hole part) 22a penetrated to an up-down direction, and the 1st electrode 2 is connected to the high frequency power supply 14 through this groove part 22a.
[0052]
The first cover body 21 is shaped so as to surround the first electrode 2 and the second cover body 22 without contacting the substrate 50 and the second electrode 3. The first cover body 21 is an insulator, but the outer wall portion thereof may be covered with a conductor to have a ground potential. If it does in this way, the 1st electrode 2 and the outer wall part of the 1st cover body 21 will have a coaxial structure, and it is desirable from a viewpoint of high frequency electric power transmission.
[0053]
The first cover body 21 has an opening in the first space SC in which at least a part of the first electrode 2 and a part of the second electrode 3 face each other. Hereinafter, the opening 25 is referred to as a first opening. . In the vicinity of the first opening 25, the bottom surface 24 of the first cover body 21 faces the substrate 50 across the second space SD of the gap G2, and this bottom surface 24 is hereinafter referred to as a second electrode facing portion. . The gap G2 is preferably set as narrow as possible within a range where the first cover body 21 and the substrate 50 do not contact each other. Further, it is preferable that the length of the second electrode facing portion 24 in the X direction in FIG. 1 is as long as possible. Furthermore, the gap G2 is preferably set narrower than the gap G1.
[0054]
The first cover body 21 has downward projecting portions 21f as shown in FIG. 2 at both ends in the direction perpendicular to the paper surface of FIG. The downward projecting portion 21f covers the substrate 50 and the second electrode 3 with a minute gap as much as possible. Moreover, the 1st cover body 21 has the recessed part 21a as shown in FIG. 5, and the 2nd cover body 22 has the attaching part 22b corresponding to this. The mounting portion 22b is fitted into the recess 21a, and the first cover body 21 and the second cover body 22 are integrated to form an integral structure (cover body 23). In the present embodiment, since the first electrode 2 is fixed to the second cover body 22, the cover body 23 and the first electrode 2 are also an integral structure. Further, as shown in FIGS. 4 and 5, the inner wall surface 21 e of the first cover body 21 is substantially in contact with the end surface 2 e of the first electrode 2 and the end surface 22 e of the second cover body 22.
[0055]
The cover body 23 is provided with a communication introduction port 26 and a communication exhaust port 27 as shown in FIGS. 2 and 3 by the first cover body 21 and the second cover body 22. As shown in FIG. 1, the communication inlet 26 communicates with the first gas inlet 4 and the communication outlet 27 communicates with the first gas outlet 5 in an airtight manner.
[0056]
The shape of the first cover body 21 and the second cover body 22 is such that the flow of the plasma processing gas flowing through the main gas flow path FR, which will be described later, is configured together with the first electrode 2 and the second electrode 3 or the substrate 50. There is no particular limitation as long as the shape does not cause a sudden change in the line. Further, it is preferable that the conductance of the flow from the first space SC toward the communication exhaust port 5 is larger than the conductance of the flow other than the main gas flow path from the first space SC to the second space SD. . In the present embodiment, as shown in FIG. 1, the shape of the first cover body 21 is such that the inner wall surface 21c is a planar shape and the subsequent inner wall surface 21d is a curved surface shape so that they are smoothly connected. Yes. The wall surface 22 c of the second cover body 22 is smoothly connected to the semicircular surface 2 a of the first electrode 2. Further, the gap G2 is narrowed in a range where the first cover body 21 and the substrate 50 do not contact each other, the length of the second electrode facing portion 24 in the X direction in FIG. 1 is set, and the gap G2 is set narrower than the gap G1. It is.
[0057]
The planar inner wall surface 21c of the first cover body 21 is opposed to the planar wall surface 22c of the second cover body 22 via the spaces SA1 and SA2, and the curved inner wall surface 21d of the first cover body 21 is the first electrode. 2 is opposed to the curved surface 2a via the spaces SB1 and SB2. Here, the left space in FIG. 1 is distinguished as SA1 and SB1, and the right space is distinguished as SA2 and SB2.
[0058]
The radius of curvature of the inner wall surface 21 d of the first cover body 21 is larger than the radius of the curved surface 2 a of the first electrode 2. Further, the center of curvature of the inner wall surface 21d is, for example, on the Y axis in FIG. 1 like the center of the curved surface 2a, and is located above the center of the curved surface 2a. As a result, the width of the space SB1 gradually decreases from the space SA1 to the first space SC, and the width of the space SB2 gradually increases from the first space SC to the space SA2. Furthermore, the width of the main gas flow path FR, which will be described later, at the boundary between the space SB1 and the space SB2 and the first space SC (the end of the first opening 25) is the tip 2at of the curved surface 2a of the first electrode 2. Is set wider than the gap G <b> 1 between the substrate 50 and the substrate 50.
[0059]
(B) Main gas flow path FR in plasma processing apparatus 100
(B-1) Configuration of main gas flow path FR
Next, the gas flow path of the plasma processing gas in the plasma processing apparatus 100 of the present embodiment will be described with reference to FIG. FIG. 6 is an enlarged view of the main gas flow path FR in FIG.
[0060]
The plasma processing gas is introduced into the chamber 1 from the first gas introduction port 4 through the communication introduction port 26 of the cover body 23 that is in airtight communication therewith. Then, the air is guided to the first space SC through the substantially airtight spaces SA1 and SB1. The plasma processing gas that has reached the first space SC is exhausted to the outside of the chamber 1 through the first exhaust port 5 that communicates with the communication exhaust port 27 in an airtight manner mainly through the substantially airtight spaces SB2 and SA2. Then, the gas flow path FR including the communication introduction port 26 to the space SA1 to the space SB1 to the first space SC to the space SB2 to the space SA2 to the communication exhaust port 27 becomes a main gas flow channel. As is apparent from FIG. 6, the main gas flow path FR includes the first electrode 2 and the second electrode 3 (or the substrate 50), and the cover body 23 including the first cover body 21 and the second cover body 22. It is comprised by the wall surface.
[0061]
The width of the main gas flow path FR is sufficiently wide and constant in the space SA1. As described above, the boundary between the space SA1 and the space SB1 is smoothly connected. Further, in the space SB1, the width of the main gas flow channel FR gradually decreases from the space SA1 to the first space SC. The width GW of the main gas flow path FR at the boundary between the space SB1 and the first space SC is set wider than the gap G1 between the tip portion 2at of the first electrode 2 and the substrate 50. After the gas flow passes through the space SB1, the wall surface that regulates one side surface of the gas flow is inherited from the inner wall surface 21d of the first cover body 21 to the surface of the substrate 50, and the first electrode 2 in the first space SC. A main gas flow path FR is formed by the curved surface 2 a and the surface of the substrate 50. Then, the width of the main gas flow channel FR gradually decreases from the space SB1 to the tip 2at of the curved surface 2a of the first electrode 2, and becomes the minimum width G1 at the tip 2at. Here, there is a concern that the gas flow from the space SB1 to the first space SC becomes unstable due to a change in the wall surface that regulates the gas flow. However, a state close to one wall surface SCW of the ideal virtual flow tube can be obtained by the inertia of the gas flow and the regulation surfaces of the width GW and the width G1 that regulate the gas flow. In the present embodiment, the width of the main gas flow path FR in the space SA1 is about 50 mm, the length is 100 mm, and the width of the main gas flow path FR in the space SB1 is gradually narrowed from the space SA1 to the first space SC. The width GW at the boundary was about 3 mm. Further, the radius of the first electrode 2 is set to 100 mm, the length of the main gas flow path FR in the first opening 25 (first space SC) is set to 50 mm, and the gap between the tip portion 2 at of the first electrode 2 and the substrate 50 is set. The gap G1 was about 2 mm. Further, the gap G2 was about 1 mm, and the length of the second electrode facing portion 24 in the X direction in FIG. 1 was 140 mm. Regarding the main gas flow path FR from the first space SC to the space SA2 through the space SB2, the change in the width is opposite to that of the main gas flow path FR from the space SA1 to the first space SC through the space SB1. Since there is the same, explanation is omitted. In addition, in the main gas flow path FR, you may provide a well-known gas dispersion plate suitably for the further stabilization of a flow.
[0062]
(B-2) Effect of main gas flow path FR
(B-2-1) In the present embodiment, the width of the main gas flow path FR gradually decreases from the space SB1, becomes the minimum at the distal end portion 2at of the first electrode 2, and then gradually increases toward the space SB2. It is getting wider. Further, the streamline F at the center in the width direction of the main gas flow channel FR has a substantially U shape as shown in FIG. Therefore, there is no sudden change in the flow line of the plasma processing gas over the entire width direction of the main gas flow path FR, and the loss of the gas flow can be greatly reduced. As a result, a large flow rate of the plasma processing gas can be stably supplied to the plasma space P without disturbing the flow. Further, the gas after the plasma treatment can be exhausted at a high speed without stagnation.
[0063]
(B-2-2) In the present embodiment, as shown in FIG. 6, the plasma P is generated only in the portion where the width of the main gas flow path FR is the minimum in the vicinity of the tip portion 2 at of the first electrode 2. Therefore, it is possible to generate a small-sized plasma that can maintain a uniform discharge state. The set value of the width G1 of the minimum width portion varies depending on the pressure of the plasma processing gas in the plasma space, but when the pressure is set to 100 Torr or higher in order to increase the plasma processing speed, as will be described later, It is about several hundred μm to several mm. In the present embodiment, such a narrow flow path is provided only in a part of the main gas flow path FR, so that the friction loss of the gas flow can be greatly reduced. As a result, even when the electrode gap (gap G1) is narrowed to generate plasma under high pressure, a large flow rate of plasma processing gas can be stably supplied. Further, the gas after the plasma treatment can be exhausted at a high speed without stagnation.
[0064]
(B-2-3) In the present embodiment, the streamline in the main gas flow path FR has a smooth substantially U shape and is a direction along the substrate 50 in the plasma space P. For this reason, even if the cover body 23 is located on the upper side without coming into contact with the substrate 50 so that the second electrode 3 on which the substrate 50 is mounted can be moved, the cover body 23 is inclined downwardly from the first opening 25. A plasma processing gas can be supplied onto the substrate 50 in the direction. Moreover, since the streamline of the gas flow is the direction along the substrate 50 in the plasma space P, the loss of the gas flow is small and a stable flow can be obtained. Then, the gas after the plasma treatment including the reaction product is exhausted by a flow in an obliquely upward direction that is a direction away from the substrate 50, so that the reaction product can be prevented from adhering to the substrate 50.
[0065]
(B-2-4) In the present embodiment, the main gas flow channel FR is not subjected to a rapid change in the flow line in the flow channel, and only a part of the flow channel has a narrow width. The conductance of the main gas flow path FR can be increased. Further, the streamline in the main gas flow path FR has a smooth substantially U shape, and the direction of the velocity vector is a direction in which leakage occurs outside the main gas flow path FR (first space SC → second space SD). Are very different. Therefore, even if the cover body 23 is not in contact with the substrate 50 and the second electrode 3, it is possible to prevent the gas from leaking outside the main gas flow path FR from the first space SC toward the second space SD. Can do. Accordingly, it is possible to stably supply a large flow rate of the plasma processing gas to the plasma space while maintaining the inside of the main gas channel substantially in a substantially airtight state. Further, the gas after the plasma treatment can be exhausted at a high speed without being retained.
[0066]
(C) Airtightness in the main gas flow path FR
In the present embodiment, the main gas flow path FR has a large conductance without a sudden change in the streamline. Further, since the direction of the velocity vector is greatly different from the direction of external leakage (first space SC → second space SD), there is little leakage to the external space from the first space SC to the second space SD, and the airtightness. A stable gas flow with a large flow rate can be formed while maintaining the above. However, in order for the main gas flow channel FR to exhibit the above-described effect (B-2) more significantly, it is desirable to further improve the airtightness in the main gas flow channel FR by the following method.
[0067]
(C-1) As shown in FIG. 6, the conductance of the gas flow flowing through the first space SC → the second space SD is sufficiently smaller than the conductance of the gas flow flowing through the first space SC → the space SB2 → the space SA2. Set as follows. That is, as described above, the gap G2 of the second space SD provided for enabling the movement of the second electrode 3 on which the substrate 502 is mounted is possible in a range where the first cover body 21 and the substrate 50 do not contact each other. It is set as narrow as possible, and the length of the second electrode facing portion 24 is set as long as possible in the X direction in the figure. Furthermore, by setting the gap G2 of the second space SD to be narrower than the minimum flow path width G1 in the main gas flow path FR, the airtightness of the main gas flow path FR can be significantly improved.
[0068]
(C-2) As shown in FIG. 2, the provision of the downward projecting portion 21f of the first cover body 21 is effective for improving the airtightness in the direction perpendicular to the paper surface of FIG. Since the downward projecting portion 21f covers the substrate 50 and the second electrode 3 with a gap as small as possible, the conductance of the space between them is also the first space in the main gas flow path FR as described above. It can be set to be sufficiently smaller than the conductance of the gas flow flowing through SC → space SB2 → space SA2.
[0069]
(C-3) It is also effective to slightly increase the pressure in the region other than the main gas flow path FR in the chamber 1 than the pressure in the main gas flow path FR. Thereby, the airtightness in the main gas flow path FR can be improved due to the pressure difference. Specifically, as shown in FIG. 1, a second gas introduction port 10 and a second gas exhaust port 11 are provided on the wall surface of the chamber 1, and a gas of the same component as the plasma processing gas or an inert gas in the chamber 1. Introduce gas. Then, the pressure in the region other than the main gas flow path FR in the chamber 1 is kept slightly higher than the pressure in the main gas flow path FR. Thereby, it can suppress that gas leaks from the inside of the main gas flow path FR to the exterior. In this case, there is a possibility that gas is mixed from the outside of the main gas flow channel FR into the main gas flow channel FR, but only a trace amount of a gas having the same component as the plasma processing gas or an inert gas is mixed. Therefore, no particular problem occurs.
[0070]
(D) Plasma processing method by plasma processing apparatus 100
Next, an example of a plasma processing method using the plasma processing apparatus 100 will be described mainly with reference to FIG.
[0071]
First, the inside of the chamber 1 is brought into a reduced pressure state by the first gas exhaust part 7 and the second gas exhaust part 13. Next, a plasma processing gas is introduced into the chamber 1 from the first gas supply unit 6 and the second gas supply unit 12.
[0072]
In the region other than the main gas flow path FR (communication introduction port 26 to space SA1 to space SB1 to first space SC to space SB2 to space SA2) and the main gas flow path FR in the chamber 1 In the state where the pressure becomes a predetermined pressure, the first gas supply unit 6 and the first gas exhaust unit 7 are used for the purpose of each plasma processing such as film formation, processing, and surface treatment in the main gas flow path FR. A plasma processing gas having a predetermined flow rate is supplied. The route from the first gas supply unit 6 to the first gas exhaust unit 7 may be circulated by a circulation system (not shown). The second gas supply unit 12 and the second gas exhaust unit 13 adjust the pressure in the region other than the main gas flow channel FR so as to be slightly higher than the pressure in the main gas flow channel FR.
[0073]
As the plasma processing gas, for example, a mixed gas of an inert gas and a reactive gas can be used. As the inert gas, He gas, Ar gas, Ne gas, or the like can be used alone or mixed with each other. However, in consideration of discharge stability and damage to the substrate, it is desirable to use He gas. On the other hand, as the reactive gas, a gas corresponding to the purpose of the plasma treatment is used. For example, when an amorphous or microcrystalline Si thin film is formed, SiH _Four A gas containing Si atoms such as gas alone or H ₂ It can be used by mixing with other gases. In addition, when processing Si-based substrates, SF ₆ And CF _Four Halogen gas such as single substance or O ₂ It can be used by mixing with other gases. Further, when a hydrophilic surface treatment is performed, an organic solvent such as alcohol can be used. Note that the gas supplied from the second gas supply unit 12 may include only the inert gas without including the reaction gas.
[0074]
The pressure of the plasma processing gas in the main gas flow path FR is preferably set to a relatively high pressure in order to increase the processing speed of the plasma processing. For example, if the reaction gas partial pressure is set to a high pressure of 10 Torr or more in order to increase the processing speed, a large amount of inert gas is added to stably generate plasma, so the pressure of the plasma processing gas is total. It becomes about 100 Torr or more. In this case, the gap G1 between the tip portion 2at of the first electrode 2 and the substrate 50 needs to be as narrow as several hundreds μm to several mm. However, according to the configuration of the plasma processing apparatus 100 of the present embodiment, this is the case. It is possible to stably supply a large flow rate of plasma processing gas even for such a narrow gap. For example, even if the pressure of the plasma processing gas is 160 Torr and the gap G1 is set to about 2 mm, a plasma processing gas of several hundred l / min or more can be supplied to the plasma space.
[0075]
In this manner, a high frequency voltage is applied between the first electrode 2 and the second electrode 3 from the high frequency power supply 14 in a state where a predetermined flow rate of the plasma processing gas is allowed to flow through the main gas flow path FR. Here, since the first electrode 2 has the curved surface shape 2a, an electric field strength distribution is generated in the first space SC. Then, a small-sized plasma P as shown in FIG. 6 is generated in the vicinity of the distal end portion 2at of the first electrode 2 having a high electric field strength. A predetermined plasma treatment is performed on the substrate 50 by the reactive species based on the reactive gas in the plasma P. For example, SiH _Four Gas and H ₂ When a reaction gas mixed with a gas is used, an amorphous or microcrystalline Si thin film is formed on the substrate 50. The region where the plasma P is generated varies depending on the pressure of the plasma processing gas, but the length of the plasma P in the X direction in FIG. 6 becomes shorter as the pressure of the plasma processing gas becomes higher. Since the plasma P that is short in the X direction can be subjected to plasma processing only on a part of the substrate 50, the entire surface of the substrate 50 is further subjected to plasma processing by moving the second electrode 3 in the X direction. . Further, the cover body 23 is not in contact with the substrate 50 and the second electrode 3 in order to move the substrate 50, but as described in the above (B) and (C), the cover body 23 is large in the main gas flow path FR. The gas for plasma processing at a flow rate can be flowed stably.
[0076]
(E) Effects of the first embodiment
(E-1) First effect (uniformization of plasma processing for a large area substrate)
In the present embodiment, since the first electrode 2 having the curved surface shape 2a is used, it is possible to generate a small-size plasma with good uniformity as in the configuration 1 based on the prior art shown in FIG. . Therefore, by moving the substrate 50, uniform plasma treatment can be performed within the substrate surface even for a large-area substrate.
[0077]
(E-2) Second effect (improving the quality of the plasma processing surface for a large area substrate)
In the present embodiment, since the main gas flow path FR exhibits the effect as described in (B-2) above, the cover body 23 is provided with the substrate 50 and the second electrode in order to move the substrate with respect to the small-size plasma. Even if it is not in contact with the gas 3, the gas after the plasma treatment can be exhausted at a high speed. Due to the contribution of both the high-speed exhaust of the gas after the plasma treatment and the small-size plasma in (E-1) above, the time during which the reaction product stays in the plasma space is further shortened, and the plasma treatment surface is more Further improvement in quality can be achieved. This can be understood from the fact that the gas replacement time t in the plasma space is expressed by the following equation.
[0078]
t = V / Q (V: volume of plasma space, Q: flow rate of plasma processing gas)
[0079]
(E-3) Third effect (higher plasma processing speed)
(E-3-1) In the present embodiment, since the main gas flow path FR exhibits the effect as described in (B-2) above, the cover body 23 is used to move the substrate with respect to the small-size plasma. Even if the substrate 50 and the second electrode 3 are not in contact with each other, a large amount of plasma processing gas can be stably supplied to the plasma space, and the plasma processing speed can be increased.
[0080]
(E-3-2) In the present embodiment, due to the effect of (B-2) (particularly, the effect of (B-2-2)), the loss of the plasma processing gas flow in the main gas flow channel FR. Can be greatly reduced. Therefore, even when the gap between the first electrode and the second electrode (G1 in FIG. 1) is very narrow, a large flow rate of plasma processing gas is stabilized in the narrow gap (plasma space). Can be supplied. Further, the gas after the plasma treatment can be exhausted at a high speed without stagnation. This effect is particularly effective when the reaction gas partial pressure is increased and the plasma processing gas (mixed gas of inert gas and reaction gas) is set to a high pressure of about 100 Torr or more. That is, even if the gap between the first electrode and the second electrode is made very narrow in order to generate plasma with a high pressure of the plasma processing gas, a large flow rate of the plasma processing gas is introduced into the plasma space. It can be supplied stably. As a result, the plasma processing speed can be further increased by both the contribution of increasing the reaction gas partial pressure and being able to supply a large flow rate of plasma processing gas.
[0081]
Note that when the plasma processing apparatus of the present embodiment is used, the pressure of the plasma processing gas is defined as 100 Torr or more as a particularly preferable plasma processing condition for the following reason.
[0082]
In order to increase the plasma processing speed, it is desired to increase the partial pressure of the reaction gas in the plasma processing gas. Here, when the reaction gas partial pressure is less than 10 Torr, it is not necessary to add an inert gas to the reaction gas (that is, the plasma processing gas is the reaction gas itself and the plasma processing gas pressure is less than 10 Torr. In this case, there is a possibility that plasma can be generated stably. However, when the reaction gas partial pressure is 10 Torr or more, it is difficult to stably generate plasma unless an inert gas is added thereto. For this reason, for the reactive gas of 10 Torr or higher, it is necessary to add an inert gas of 90 Torr or higher so that the pressure of the plasma processing gas is 100 Torr or higher. Further, even if the partial pressure of the reactive gas is less than 10 Torr, it is desirable from the viewpoint of plasma stability to add a large amount of inert gas to the reactive gas so that the pressure of the plasma processing gas is 100 Torr or higher. Therefore, in order to generate stable plasma and increase the plasma processing speed, it is desired that the pressure of the plasma processing gas (mixed gas of the inert gas and the reactive gas) be 100 Torr or more.
[0083]
However, when the plasma processing gas is set to a high pressure of 100 Torr or more, the gap between the pair of electrodes needs to be very narrow based on Paschen's law. In this case, the gap is about several hundred μm to several mm. However, in a conventional apparatus using parallel plate type electrodes (for example, FIG. 18) or an apparatus not provided with a cover body that restricts the gas flow (for example, FIG. 17), the conductance of the gas flow flowing through the narrow gap portion is small. Due to its small size, it is very difficult to stably supply a large flow rate of plasma processing gas.
[0084]
On the other hand, in this embodiment, the loss of the flow of the plasma processing gas in the main gas flow channel FR is greatly reduced by the main gas flow channel FR exhibiting the effect (B-2). As a result, a high-pressure plasma processing gas of 100 Torr or more can be stably supplied at a large flow rate. In particular, the effect (B-2-2) greatly contributes to this point. That is, in the plasma processing using the plasma processing apparatus of the present embodiment, the pressure of the plasma processing gas may be any pressure, but particularly under a high pressure of 100 Torr or more, which is difficult with the conventional apparatus. Processing is also possible. Therefore, it is possible to increase the reaction gas partial pressure and further improve the processing speed.
[0085]
As described in the above (E-1) to (E-3), according to the present embodiment, the plasma processing speed is increased, the plasma processing is uniformized, and the plasma processing surface is difficult to achieve with the combination of the conventional techniques. The three requirements of high quality can be satisfied at the same time. In particular, the effect of the present embodiment is more remarkable for a large plate-like substrate that needs to be subjected to plasma treatment while moving the substrate.
[0086]
(Example 1)
An amorphous silicon thin film was formed in a 30 cm × 30 cm region on a glass substrate using the plasma processing apparatus 100 shown in FIG. The plasma processing gas is He: SiH. _Four : H ₂ = The ratio of 96.7: 0.3: 3 was passed through the main gas flow path FR at a total flow rate of 150 LM. The pressure in the main gas flow path FR was maintained at 160 Torr. In this case, the flow rate of the plasma processing gas flowing in the main gas flow path (160 Torr) is about 700 l / min, and SiH _Four The partial pressure is about 0.5 Torr. As a result, the film formation rate: about 30 Å / s, the film thickness distribution in the substrate surface: 5% or less, photosensitivity (photoconductivity / dark conductivity): 10 ⁶ An amorphous silicon thin film of the order was obtained, and it was possible to satisfy simultaneously the speeding up of the plasma processing, the improvement of the quality of the plasma processing surface and the uniformization of the plasma processing, which are the objects of the present invention.
[0087]
(Modification 1 of the first embodiment)
As described above, in the present invention, in the plasma processing apparatus that performs the plasma processing while moving the second electrode 3, the main gas flow from the first electrode 2, the second electrode 3 or the substrate 50, and the cover body 23. The path FR is configured so that a rapid change is not applied to the flow line of the plasma processing gas flowing in the main gas flow path FR. As a result, the conductance in the main gas flow path FR is increased, and even if the cover body 23 can move the second electrode 3 without coming into contact with the substrate 50 and the second electrode 3, it is functionally provided in the main gas flow path FR. While maintaining a substantially airtight state, a large flow rate of plasma processing gas can be stably flowed. One of the most preferred embodiments based on this basic idea is the first embodiment shown in FIG. However, based on the basic idea of the present invention, a modification as shown in FIG. 14 is also possible.
[0088]
14 differs from the first embodiment shown in FIG. 1 in that the center of curvature of the inner wall surface 21d of the first cover body 21 and the center of the curved surface 2a of the first electrode 2 are different. It is the point which is made to correspond substantially. That is, the first electrode 2 in FIG. 1 is moved upward. In this case, the width of the space SB1 and the space SB2 is substantially constant from the space SA1 to the first space SC and from the first space SC to the space SA2, but the main gas flow is the same as in the first embodiment. The stream line of the plasma processing gas flowing in the path FR can be formed into a smooth substantially U shape. However, as understood from the geometric arrangement, in the first modification, the gap G1 between the tip 2at of the first electrode 2 and the substrate 50 is set wider than that in the first embodiment. Therefore, in the first modification, the second electrode 3 can be moved with respect to the small-sized plasma and a large flow rate of the plasma processing gas can be stably flowed to satisfy the above three requirements at the same time. Since G1 is wide, it is difficult to generate plasma under high pressure, which is inferior to the first embodiment. In this modification as well, it goes without saying that the configuration for further improving the airtightness in the main gas flow channel as shown in (C) of the first embodiment is effective.
[0089]
(Modification 2 of the first embodiment)
In the said 1st Embodiment and the modification 1, as one of the most suitable embodiment, it showed about the case where the streamline of the plasma processing gas in the main gas flow path FR was made into a substantially U shape. However, the basic idea of the present invention is to prevent a rapid change in the flow line of the plasma processing gas flowing in the main gas flow path FR in the plasma processing apparatus that performs the plasma processing while moving the second electrode 3. To increase conductance. Therefore, based on the basic idea of the present invention, a modification as shown in FIG. 15 is possible.
[0090]
In the second modification shown in FIG. 15, the space SB1, the space SB2, and the first space SC in the main gas flow channel FR are the same as those in the first embodiment shown in FIG. The second modification is different from the first embodiment in that the stream lines of the plasma processing gas in the spaces SA1 and SA2 are linearly parallel to the surface of the substrate 50. The cover body 23 in this case is, for example, a one-piece insulator as illustrated. Note that an external perspective view of the cover body 23 is the same as FIG. 12 described in a second embodiment described later. That is, in this modification, although the loss at the boundary portion of the space SA1 → the space SB1 and the space SB2 → the space SA2 is slightly larger than that in the first embodiment, the streamline is suddenly changed as illustrated. Absent. Therefore, although inferior to the first embodiment, a large flow rate of plasma processing gas can be stably flowed, and the above three requirements can be satisfied simultaneously. In this modification as well, it goes without saying that the configuration for further improving the airtightness in the main gas flow channel as shown in (C) of the first embodiment is effective.
[0091]
(Modification 3 of the first embodiment)
In the said 1st Embodiment, the modification 1, and the modification 2, it showed about the case where the surface of the 1st electrode 2 was made into the curved-surface shape 2a as one of suitable embodiment. However, the basic idea of the present invention is to prevent a rapid change in the streamline of the plasma processing gas flowing in the main gas flow path FR in the plasma processing apparatus that performs the plasma processing while moving the second electrode 3. To increase conductance. Therefore, based on the basic idea of the present invention, a modification as shown in FIG. 16 is possible.
[0092]
The third modification shown in FIG. 16 differs from the second modification shown in FIG. 15 in that the surface of the first electrode 2 has a planar shape 2a ′. In the third modification, the surface 21d in the vicinity of the opening of the cover body 23 has a curved surface shape, as in the first embodiment. “The cover body 23 is positioned above the substrate without contacting the substrate. Even so, the plasma processing gas is supplied from the first opening 25 of the cover body 23 onto the substrate 50 in the obliquely downward direction. In the present modification, the stream line of the plasma processing gas in the main gas flow path FR is substantially linear, and a sudden change is not added. However, in this variation, in order to stably flow a large flow rate of plasma processing gas, at least in the space SA1 and the space SA2, the width of the main gas flow path FR is approximately the same as that in the variation 2 shown in FIG. Need to be wide. For this reason, in the third modification, the gap G1 between the planar shape portion 2a ′ of the first electrode 2 and the substrate 50 is set wider than that in the second modification. Therefore, in the third modification, the second electrode 3 can be moved with respect to the small-sized plasma and a large flow rate of the plasma processing gas can be stably flowed to satisfy the above three requirements at the same time. Since G1 is wide, it becomes difficult to generate plasma under high pressure, which is inferior to the second modification. In this modification as well, it goes without saying that the configuration for further improving the airtightness in the main gas flow channel as shown in (C) of the first embodiment is effective.
[0093]
(Second Embodiment)
In the present embodiment, a plasma processing apparatus and a plasma processing method capable of performing suitable plasma processing on a sheet-like substrate and a cylindrical substrate will be described. In the present embodiment, the method for maintaining the airtightness of the main gas flow path and the plasma processing method are the same as those in the first embodiment, and thus the description thereof is omitted. FIG. 7 is a cross-sectional view showing a schematic configuration of the plasma processing apparatus 200 of the present embodiment, FIG. 8 is a perspective view showing the main part of the plasma processing apparatus 200, and FIG. 9 shows a cross section in the plane PL1 of FIG. 10 is a cross-sectional view of the plane PL2 in FIG. 8, FIG. 11 is an exploded perspective view of each part of FIG. 9, and FIG. 12 is a perspective view of the cover body 23. 13 is an enlarged view showing the main gas flow path FR2 in the plasma processing apparatus 200. FIG. Hereinafter, the configuration of the plasma processing apparatus 200 according to the present embodiment and the main gas flow path FR2 will be described with reference to FIGS. In the following, plasma processing for a sheet-like substrate will be described. However, if a cylindrical second electrode to be described later is a cylindrical substrate itself, plasma processing for the cylindrical substrate is also possible.
[0094]
(A) Components of the plasma processing apparatus 200
Hereinafter, components of the plasma processing apparatus 200 will be described mainly with reference to FIG. Although most of the components of the present embodiment have the same function as the first embodiment, although the shapes are different, the same symbols are used for the components having the same function as the first embodiment. Detailed description will be omitted.
[0095]
The plasma processing apparatus 200 of the present embodiment is greatly different from the plasma processing apparatus 100 of the first embodiment in that the substrate is a sheet-like substrate 50, the second electrode 3 is a rotatable cylindrical shape, The shape of the cover body 23 and the shape of the main gas flow path FR2.
[0096]
The sheet-like substrate 50 is introduced into the chamber 1 through the substrate introduction port 60 and is conveyed by the rotation of the second electrode 3 in the DR direction while being in close contact with the cylindrical second electrode 3. Thereafter, the liquid is discharged out of the chamber 1 through the substrate discharge port 61.
[0097]
The cover body 23 is an insulator and is a one-piece structure. When viewed from the side with respect to the paper surface of FIG. 7, the cover body 23 has a substantially rectangular uniform opening as shown in FIGS. 11 and 12. One end of the opening is a communication introduction port 26 and the other end is a communication exhaust port 27. The cover body 23 has a first opening 25 on the lower surface and a second opening 23a on the upper surface.
[0098]
The first electrode 2 has a curved surface 2 a and is fitted into the second opening 23 a of the cover body 23 as shown in FIGS. 9 and 11. Then, the attachment portion 2b contacts the upper surface 23b of the cover body 23, and the end portion of the curved surface 2a is connected to the end portion on the upper inner wall surface 23c side of the second opening portion 23a. Thus, the 1st electrode 2 and the cover body 23 comprise the integral structure. The curved surface 2 a of the first electrode 2 protrudes downward from the upper inner wall surface 23 c of the cover body 23, faces the first opening 25 of the cover body 23, and is connected to the high frequency power supply 14.
[0099]
The cylindrical second electrode 3 and the sheet-like substrate 50 are inserted from the first opening 25 without contacting the inside of the cover body 23, and protrude upward. The first electrode 2 is opposed to the first space SC. Furthermore, the tip portion 2at of the first electrode 2 and the sheet-like substrate 50 on the tip portion 3at of the second electrode 3 face each other with a gap G1 therebetween. In the vicinity of the facing portion of the gap G1, a small-sized plasma P as shown in FIG. 7 is generated. Furthermore, as shown in FIG. 7, it is preferable that the radius of curvature of the curved surface 2 a of the first electrode 2 is set substantially equal to the radius of the cylindrical second electrode 3. Further, it is preferable that the protruding amount of the tip portion 2at of the first electrode 2 from the upper inner wall surface 23c and the protruding amount of the tip portion 3at of the second electrode 3 from the lower inner wall surface 23d are set substantially equal.
[0100]
The second electrode facing portion 24 of the cover body 23 has a curved surface shape, and faces the sheet-like substrate 50 with the second space SD of the gap G2. The gap G2 is preferably set as narrow as possible within a range in which the cover body 23 and the substrate 50 do not contact each other. Furthermore, the gap G2 is preferably set narrower than the gap G1.
[0101]
Both ends of the cover body 23 in the direction perpendicular to the paper surface of FIG. 7 cover the side surface of the second electrode 3 with a minute space as shown in FIG. The inner wall surface 23e of the cover body 23 is substantially in contact with the end surface 2e of the first electrode 2.
[0102]
(B) Main gas flow path FR2 in plasma processing apparatus 200
(B-1) Configuration of main gas flow path FR2
Next, the gas flow path of the plasma processing gas in the plasma processing apparatus 200 of the present embodiment will be described with reference to FIG. FIG. 13 is an enlarged view of the main gas flow path FR2 in FIG.
[0103]
The plasma processing gas is introduced into the chamber 1 from the first gas introduction port 4 through the communication introduction port 26 of the cover body 23 that is in airtight communication therewith. Then, the air is guided to the first space SC through the airtight space SA1. The plasma processing gas that has reached the first space SC is exhausted to the outside of the chamber 1 through the first gas exhaust port 5 that is airtightly communicated with the communication exhaust port 27 mainly through the airtight space SA2. The gas flow path FR2 from the communication introduction port 26 to the space SA1 to the first space SC to the space SA2 to the communication exhaust port 27 becomes the main gas flow channel. As is apparent from FIG. 13, the main gas flow path FR <b> 2 is configured by the wall surfaces of the first electrode 2 and the second electrode 3 (or the substrate 50) and the cover body 23.
[0104]
The width of the main gas flow path FR2 is sufficiently wide and constant in the space SA1. In the subsequent first space SC, the width of the main gas flow path FR2 is gradually reduced by the curved surface 2a of the first electrode 2 and the cylindrical surface of the second electrode 3 (the surface of the sheet-like substrate 50). The minimum width G1 is the portion where the tip 2at and the tip 3at of the second electrode 3 face each other. In the present embodiment, the width of the main gas flow path FR2 in the space SA1 is 50 mm and the length is 100 mm. The length of the first opening 25 is 130 mm, the length of the second opening 23a is 130 mm, and the gap G1 is about 2 mm by projecting the first electrode 2 and the second electrode 3 from the opening. Furthermore, the radius of the second electrode was 100 mm, the gap G2 was about 1 mm, and the circumferential length of the second electrode facing portion 24 was 50 mm. The main gas flow path FR2 extending from the first space SC to the space SA2 is the same as the main gas flow path FR2 extending from the space SA1 to the first space SC, although the change in the width is the same, and thus the description thereof is omitted. To do. In addition, in the main gas flow path FR2, a known gas dispersion plate may be appropriately provided in order to further stabilize the flow.
[0105]
(B-2) Effect of main gas flow path FR2
(B-2-1) The width of the main gas flow path FR2 in the present embodiment gradually decreases from the space SA1 side in the first space SC, becomes minimum at the gap G1 portion, and thereafter toward the space SA2 side. It is getting wider gradually. Further, the streamline F2 at the center in the width direction of the main gas flow path FR2 is substantially linear as shown in FIG. Furthermore, the shape of the main gas flow path FR2 is substantially symmetrical with respect to the center line in the width direction. Therefore, there is no sudden change in the flow line of the plasma processing gas over the entire width direction of the main gas flow path FR2, and the loss of gas flow can be greatly reduced. As a result, a large flow rate of the plasma processing gas can be stably supplied to the plasma space P without disturbing the flow. Further, the gas after the plasma treatment can be exhausted at a high speed without stagnation.
[0106]
(B-2-2) In the present embodiment, as shown in FIG. 13, the plasma P is generated only in the vicinity of the gap G1 portion where the width of the main gas flow path FR2 is minimized, so that a uniform discharge state is maintained. As small as possible plasma can be generated. Further, in the present embodiment, such a narrow flow path is provided only in a part of the main gas flow path FR2, so that the friction loss of the gas flow can be greatly reduced. As a result, even when the gap G1 is set to be very narrow in order to generate plasma under high pressure, a large amount of plasma processing gas can be stably supplied. Further, the gas after the plasma treatment can be exhausted at a high speed without stagnation.
[0107]
(B-2-3) In the present embodiment, the streamline F2 at the center in the width direction of the main gas flow path FR2 is substantially linear, and this flows along the center of the plasma space P along the surface of the substrate 50. In the plasma space P, the surrounding streamline F2 ′ is also along the substrate. For this reason, in order to enable the second electrode 3 on which the sheet-like substrate 50 is mounted to rotate, even if the cover body 23 is not in contact with the substrate 50, the plasma processing gas is not directly lost into the plasma space P without loss. It can flow. As a result, a large amount of plasma processing gas can be supplied more stably. Then, the plasma-treated gas containing the reaction product can be exhausted at a higher speed without being retained.
[0108]
(B-2-4) In the present embodiment, the main gas flow channel FR2 does not undergo a sudden change in the streamline in the flow channel, and there are only a part of the narrow channel width. The conductance of the main gas flow path FR2 can be increased. The stream line F2 at the center in the width direction of the main gas flow path FR2 is substantially straight, and the direction of the velocity vector leaks outside the main gas flow path FR2 (first space SC → second space SD). Is very different. Therefore, even if the cover body 23 is not in contact with the substrate 50 and the second electrode 3, it is possible to suppress the gas from leaking to the outside of the main gas flow path FR2. Accordingly, it is possible to stably supply a large flow rate of the plasma processing gas to the plasma space while maintaining the inside of the main gas channel substantially in a substantially airtight state. Further, the gas after the plasma treatment can be exhausted at a high speed without being retained.
[0109]
According to the present embodiment, since the main gas flow path FR2 exhibits the effect as described in (B-2) above, the same effects as those in the first embodiment can be obtained for the plasma treatment for the sheet-like substrate or the cylindrical substrate. That is, it is possible to simultaneously satisfy the three requirements of higher plasma processing speed, uniform plasma processing, and higher quality of the plasma processing surface.
[0110]
(Example 2)
When an amorphous silicon thin film was formed on a long plastic film under the same conditions as in Example 1 using the plasma processing apparatus 200 shown in FIG. 7, results equivalent to those in Example 1 were obtained.
[0111]
【The invention's effect】
As described above in detail, according to the present invention, a small-size plasma is generated in the first space that is a facing portion between at least a part of the first electrode and a part of the second electrode, In the plasma processing apparatus capable of performing uniform plasma processing on the entire surface of the substrate by moving the second electrode (and the substrate mounted thereon), the first electrode and the first electrode without contacting the second electrode and the substrate A cover body constituting the main gas flow path is provided together with the two electrodes or the substrate. The first electrode, the second electrode, the second electrode, the second electrode, the second electrode, the second electrode, the second electrode, the second electrode, the second electrode, the second electrode, the second electrode, and the like. Since the electrode and the cover body are arranged, it is possible to supply a large flow rate of the plasma processing gas and to exhaust the gas after the plasma processing at high speed without disturbing the flow of the plasma space. Further, the first conductance is such that the conductance of the flow from the first space toward the communication exhaust port in the main gas flow path is larger than the conductance of the flow other than the main gas flow path from the first space to the second space. Since the electrode, the second electrode, and the cover body are arranged, the gas leakage to the portion other than the main gas passage can be further prevented, and the airtightness in the main gas passage can be further enhanced. As a result, the three requirements of high speed plasma processing, high quality plasma processing surface and uniform plasma processing can be satisfied at the same time. In particular, according to the present invention, a remarkable effect can be obtained with respect to plasma processing for a large area substrate and plasma processing for a sheet-like substrate.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a schematic configuration of a plasma processing apparatus according to a first embodiment.
FIG. 2 is a perspective view showing a main part of the plasma processing apparatus of the first embodiment.
3 is a perspective view showing a cross section in a plane PL1 of FIG. 2; FIG.
4 is a cross-sectional view taken along a plane PL2 in FIG.
5 is an exploded perspective view of each part of FIG. 3. FIG.
FIG. 6 is an enlarged view showing a main gas flow path in the plasma processing apparatus of the first embodiment.
FIG. 7 is a cross-sectional view showing a schematic configuration of a plasma processing apparatus according to a second embodiment.
FIG. 8 is a perspective view showing a main part of a plasma processing apparatus according to a second embodiment.
9 is a perspective view showing a cross section in a plane PL1 of FIG. 8. FIG.
10 is a cross-sectional view taken along a plane PL2 in FIG.
11 is an exploded perspective view of each part of FIG. 9;
FIG. 12 is a perspective view showing a cover body in the plasma processing apparatus of the second embodiment.
FIG. 13 is an enlarged view showing a main gas flow path in the plasma processing apparatus of the second embodiment.
FIG. 14 is a cross-sectional view illustrating a schematic configuration of a plasma processing apparatus according to a first modification.
FIG. 15 is a cross-sectional view showing a schematic configuration of a plasma processing apparatus according to Modification 2;
FIG. 16 is a cross-sectional view showing a schematic configuration of a plasma processing apparatus of a third modification.
FIG. 17 is a cross-sectional view showing a schematic configuration of a plasma processing apparatus having a conventional configuration 1;
18 is a cross-sectional view showing a schematic configuration of a plasma processing apparatus of conventional configuration 2. FIG.
[Explanation of symbols]
1 chamber
2 First electrode
3 Second electrode
4 First gas inlet
5 First gas exhaust port
6 First gas supply section
7 First gas exhaust
8, 9 Piping
10 Second gas inlet
11 Second gas exhaust port
12 Second gas supply unit
13 Second gas exhaust
14 High frequency power supply
21 First cover body
22 Second cover body
23 Cover body
23a Second opening
24 Second electrode facing part
25 First opening
26 Communication port
27 Communication outlet
50 substrates
100, 200 Plasma processing apparatus
FR, FR2 Main gas flow path
SC 1st space
SD second space
G1, G2 gap

Claims (12)

A first electrode and a second electrode on which a substrate is mounted are disposed in a chamber having a first gas inlet and a first gas outlet;
At least a part of the first electrode and a part of the second electrode are arranged opposite to each other with the first space therebetween and only through the substrate;
A plasma processing gas is introduced into the first space from the first gas introduction port, and a high frequency voltage is applied between the first electrode and the second electrode, so that at least a part of the first space is applied. A plasma processing apparatus for performing plasma processing on the substrate by generating plasma and further moving the second electrode on which the substrate is mounted,
A communication inlet communicating with the first gas inlet;
A communication exhaust port communicating with the first gas exhaust port;
A first opening that opens in the first space;
A cover body having a second electrode facing portion facing the second electrode or the substrate across a second space in the vicinity of the first opening;
The cover body, together with the first electrode and the second electrode or the substrate, does not come into contact with the second electrode and the substrate, passes from the communication introduction port to the communication exhaust port through the first space. Configure the main gas flow path of the plasma processing gas toward
A plasma processing apparatus in which the first electrode, the second electrode, and the cover body are arranged so that a rapid change is not applied to a flow line of the plasma processing gas flowing through the main gas flow path. The conductance of the flow from the first space toward the communication exhaust port in the main gas flow path is larger than the conductance of the flow from the first space to the second space other than the main gas flow path. The plasma processing apparatus according to claim 1, wherein the first electrode, the second electrode, and the cover body are arranged. The chamber further has a second gas inlet,
A gas having the same component as the plasma processing gas or an inert gas is introduced into the chamber from the second gas introduction port, and the pressure in a region other than the main gas channel is higher than the pressure in the main gas channel. The plasma processing apparatus according to claim 1, wherein a high pressure can be maintained. In the portion where the plasma is generated in the first space,
2. The first electrode, the second electrode, and the cover body are disposed so that a streamline of the plasma processing gas flowing through the main gas flow path is substantially in a direction along the substrate surface. The plasma processing apparatus according to claim 3. The plasma processing apparatus according to claim 1, wherein the first electrode has a curved surface shape in at least the first space. In a substantially central portion in the width direction of the main gas flow path,
The first electrode, the second electrode, and the second electrode so that a streamline of the plasma processing gas flowing through the main gas flow path is substantially U-shaped from the communication introduction port, the first space, and the communication exhaust port. The plasma processing apparatus according to any one of claims 1 to 5, wherein an electrode and the cover body are disposed. The first electrode, the second electrode, and the cover body are arranged so that the width of the main gas channel is minimized at the substantially U-shaped tip.
The plasma processing apparatus according to claim 6, wherein plasma is generated in the vicinity of a portion where the width of the main gas channel is minimized. In a substantially central portion in the width direction of the main gas flow path,
The first electrode and the second electrode are arranged such that a streamline of the plasma processing gas flowing through the main gas flow path is substantially linear across the communication introduction port, the first space, and the communication exhaust port. The plasma processing apparatus according to any one of claims 1 to 5, wherein the cover body is disposed. The plasma processing apparatus according to claim 8, wherein the second electrode has a cylindrical shape and is rotatable about a central axis thereof. The plasma processing apparatus according to claim 9, wherein a sheet-like substrate is mounted as the substrate, and the sheet-like substrate is movable while being in close contact with the second electrode by rotation of the second electrode. The first electrode has a curved portion at least in the first space, and the radius of curvature of the curved portion of the first electrode is substantially the same as the radius of the cylindrical second electrode;
The tip of the curved portion of the first electrode substantially faces the tip of the cylindrical second electrode;
The first electrode, the second electrode, and the cover body are arranged so that the width of the main gas flow path is minimized at the facing portion between the tip portion of the first electrode and the tip portion of the second electrode. And
The plasma processing apparatus according to claim 9 or 10, wherein plasma is generated in the vicinity of the facing portion where the width of the main gas flow path is minimized. A plasma processing method for performing plasma processing on a substrate using the plasma processing apparatus according to claim 1.

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