JP5272956B2 - Plasma processing apparatus and plasma processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a decrease in exhaust efficiency of a processing chamber even when an interval between an electrode and a back member is made narrow. <P>SOLUTION: A high-frequency electrode 320 is disposed in the processing chamber 100, and a high frequency is applied to it. The top surface of the high-frequency electrode 320 faces a workpiece 10. The back member 210 is provided apart from a backside of the high-frequency electrode 320 so as to cover the backside. A space between the back member 210 and high-frequency electrode 320 serves as the exhaust route of the processing chamber 100. The high-frequency electrode 320 is formed of: a plate-like surface member 322 forming the top surface of the high-frequency electrode 320; and a housing 324 fitted to the backside of the surface member 322. The surface member 322 is made of metal such as stainless steel, for example. The housing 324 is in a box shape, and made of a porous plate, for example, a punching metal obtained by forming many holes in a metal plate such as stainless steel sheet by punching. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a plasma processing apparatus and a plasma processing method.

  Processing an object to be processed such as a substrate using plasma, for example, performing a film forming process by a plasma CVD method is widely used for manufacturing a solar cell or a semiconductor device, for example. As one of plasma processing apparatuses that process an object to be processed using plasma, there is a plasma processing apparatus having parallel plate electrodes (see, for example, Patent Documents 1 and 2). In this plasma processing apparatus, two flat electrodes facing each other are arranged in a processing chamber, and a high frequency is applied to at least one of the electrodes to generate plasma in a space between the two electrodes. is there.

  In particular, Patent Document 2 describes that an exhaust block is provided on the back surface of the high voltage electrode, and the processing chamber is exhausted through a gap between the high voltage electrode and the exhaust block.

JP-A-8-293491 JP 2001-53313 A

  As described in Patent Document 2, when a back member is provided on the back surface side of the electrode and the inside of the processing chamber is exhausted through a space between the back member and the electrode, it is necessary to input power efficiently. For this reason, it may be necessary to reduce the distance between the electrode and the back member. However, in this case, the exhaust resistance in the space between the back member and the electrode increases, and the exhaust efficiency of the processing chamber decreases.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a plasma processing apparatus and a plasma that can suppress a reduction in exhaust efficiency of the processing chamber even if the interval between the electrode and the back member is narrowed. It is to provide a processing method.

According to the present invention, a processing chamber for processing an object to be processed with plasma;
A high frequency electrode disposed in the processing chamber, to which a high frequency is applied, and a surface facing the object to be processed;
A back member provided apart from the back surface so as to cover the back surface of the high-frequency electrode, and a space between the high-frequency electrode serving as an exhaust route of the processing chamber;
With
The high-frequency electrode is
A first hollow portion provided inside the high-frequency electrode;
A first opening that is provided on a side surface of the high-frequency electrode and connects a space facing the side surface among the spaces located around the high-frequency electrode, to the first hollow portion;
A second opening provided on the back surface of the high-frequency electrode and connecting the first hollow portion to a space between the high-frequency electrode and the back member;
A plasma processing apparatus is provided.

According to the present invention, a processing chamber for processing an object to be processed with plasma;
A high frequency electrode disposed in the processing chamber, to which a high frequency is applied, and a surface facing the object to be processed;
A back member provided apart from the back surface so as to cover the back surface of the high-frequency electrode, and a space between the high-frequency electrode serving as an exhaust route of the processing chamber;
A plasma processing method of processing the object to be processed using a plasma processing apparatus comprising:
The high-frequency electrode is
A first hollow portion provided inside the high-frequency electrode;
A first opening that is provided on a side surface of the high-frequency electrode and connects a space facing the side surface among the spaces located around the high-frequency electrode, to the first hollow portion;
A second opening provided on the back surface of the high-frequency electrode and connecting the first hollow portion to a space between the high-frequency electrode and the back member;
Have
In addition to the space, a plasma processing method is provided in which the processing chamber is exhausted through the first opening, the first hollow portion, and the second opening.

  According to the present invention, even if the interval between the high-frequency electrode and the back member is narrowed, the exhaust efficiency of the processing chamber can be suppressed from decreasing.

It is a figure which shows the structure of the plasma processing apparatus which concerns on 1st Embodiment. It is a principal part enlarged view of the plasma processing apparatus shown in FIG. It is a figure which shows the structure of the plasma processing apparatus which concerns on 2nd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

  FIG. 1 is a diagram illustrating a configuration of a plasma processing apparatus according to the first embodiment. This plasma processing apparatus includes a processing chamber 100, a high-frequency electrode 320, and a back member 210. The processing chamber 100 processes the target object 10 such as a substrate with plasma. The process performed here is a film forming process by, for example, a plasma CVD method. The film | membrane formed into a film is any layer which forms the photoelectric conversion element of a solar cell, for example.

  The high frequency electrode 320 is disposed in the processing chamber 100 and is applied with a high frequency. The high frequency is, for example, 10 MHz or more and 100 MHz or less. The surface of the high frequency electrode 320 faces the object to be processed 10. The back member 210 is provided away from the back surface so as to cover the back surface of the high-frequency electrode 320. A space 504 between the back member 210 and the high-frequency electrode 320 serves as an exhaust route for the processing chamber 100. The high-frequency electrode 320 includes a first hollow portion 325 provided inside the high-frequency electrode 320, a first opening 321a provided on a side surface of the high-frequency electrode 320, and a second opening 321b provided on the back surface of the high-frequency electrode 320. And. The first opening 321 a connects the space 502 facing the side surface of the high-frequency electrode 320 among the spaces located around the high-frequency electrode 320 to the first hollow portion 325. The second opening 321 b connects the first hollow portion 325 to the space 504 between the high-frequency electrode 320 and the back member 210.

  The plasma processing apparatus according to this embodiment is a parallel plate type plasma processing apparatus. The workpiece 10 is in contact with the ground electrode 310. The ground electrode 310 is disposed in the processing chamber 100 so as to face the high-frequency electrode 320. When a high frequency is applied to the high frequency electrode 320 from the high frequency power source 400 via the matching unit 410, plasma is generated in the discharge space between the high frequency electrode 320 and the ground electrode 310, and the object to be processed 10 is processed. The ground electrode 310 has a built-in heater, and heats the object 10 to be processed. In the example shown in the figure, the ground electrode 310 and the high-frequency electrode 320 are arranged so that the surfaces are vertical. For this reason, the to-be-processed object 10 is processed in the state standing upright.

  The high-frequency electrode 320 is formed of a plate-like surface member 322 that forms the surface of the high-frequency electrode 320 and a housing 324 attached to the back surface of the surface member 322. The surface member 322 is made of a metal such as stainless steel, for example. The housing 324 has a box shape and is formed of a punching metal in which a large number of holes are formed by punching in a perforated plate, for example, a metal plate such as stainless steel. The hole located on the side surface of the housing 324 corresponds to the above-described first opening 321a, the hole located on the back surface of the housing 324 corresponds to the above-described second opening 321b, and the internal space of the housing 324 is A first hollow portion 325 that connects the first opening 321a and the second opening 321b to each other is formed. The planar shape of the housing 324 is substantially the same as the planar shape of the surface member 322, but may be smaller than the planar shape of the surface member 322.

  The back member 210 is made of a conductive material such as stainless steel, and has a shape that covers the side surface and the back surface of the high-frequency electrode 320. In the present embodiment, the back member 210 has a flat plate portion 212 and a convex portion 214. The flat plate portion 212 covers the back surface of the high-frequency electrode 320. The flat plate portion 212 has a planar shape similar to that of the high frequency electrode 320 and is slightly larger than the high frequency electrode 320. The convex portion 214 is provided on the entire periphery of the peripheral portion of the flat plate portion 212 and protrudes from the peripheral portion of the flat plate portion 212 so as to cover the side surface of the high-frequency electrode 320. In the example shown in this figure, when the surface of the ground electrode 310 is used as a reference, the tip of the convex portion 214 is positioned at substantially the same height as the surface of the surface member 322 of the high-frequency electrode 320.

  A space 504 is provided between the back member 210 and the high-frequency electrode 320. An exhaust pipe 330 is attached to the flat plate portion 212 of the back member 210. The exhaust pipe 330 is provided at a position off the center of the flat plate portion 212 and is connected to an exhaust pump (not shown). This exhaust pump is provided to exhaust the discharge space between the high-frequency electrode 320 and the ground electrode 310. That is, when the exhaust pump is operated, the process gas and particles located in the discharge space between the high frequency electrode 320 and the ground electrode 310 are exhausted as spaces 502 and 504 between the back member 210 and the high frequency electrode 320 and It is exhausted through the exhaust pipe 330. When viewed from a direction perpendicular to the high-frequency electrode 320, the exhaust pipe 330 is located inside the high-frequency electrode 320.

  In the present embodiment, the high frequency power output from the high frequency power source 400 is input to the input unit 326 provided at the center of the flat plate portion 212 of the back member 210. The back member 210 and the surface member 322 of the high-frequency electrode 320 are connected to each other via a connection plate 328 provided at the center of the flat plate portion 212. For this reason, the high frequency power output from the high frequency power supply 400 is transmitted to the surface member 322 via the flat plate portion 212 and the connection plate 328 of the back member. The back member 210 has the same potential as the high-frequency electrode 320 and functions as a shield member for the high-frequency electrode 320.

  The back and side surfaces of the ground electrode 310 are covered with a back member 220. The back member 220 is made of a conductive material such as stainless steel, and has a flat plate portion 222 and a convex portion 224. The planar portion 222 has a planar shape similar to that of the ground electrode 310 and is slightly larger than the ground electrode 310. The convex portion 224 is provided on the entire periphery of the peripheral portion of the flat plate portion 222. The flat plate portion 222 covers the back surface of the ground electrode 310, and the convex portion 224 covers the side surface of the ground electrode 310. The flat plate portion 222 has the support shaft 312 of the ground electrode 310 passing through the center thereof, and is attached to the support shaft 312 at this penetrating portion. The back member 220 is grounded via a support shaft 312 and a shield member 230 described later, and has the same potential as the ground electrode 310.

  The tip of the convex portion 224 is connected to the shield member 230. The shield member 230 has a covering part 232 and a connection part 234. The covering portion 232 has conductivity. The covering portion 232 is located outside the convex portion 214 of the back member 210 and surrounds at least a part of the back member 210 of the high-frequency electrode 320. The covering portion 232 has one end connected to the housing 110 of the processing chamber 100 and the other end connected to the connecting portion 234. The connection portion 234 is a ring-shaped or rectangular conductive plate, and is substantially parallel to the surface of the high-frequency electrode 320. The connection portion 234 has one end on which one end of the convex portion 224 of the back member 220 of the ground electrode 310 is attached, and the other portion on the other end of the convex portion 214 of the back member 210 of the high-frequency electrode 320 via the insulating member 236. The tip is attached.

  The process gas is introduced into the discharge space between the ground electrode 310 and the high-frequency electrode 320 via the gas introduction tube 327. In the present embodiment, the gas introduction pipe 327 penetrates the high frequency electrode 320 and introduces a process gas from the high frequency electrode 320 side. However, the gas introduction tube 327 may introduce process gas into the discharge space between the ground electrode 310 and the high-frequency electrode 320 from the side surface side.

  In such a configuration, the ground electrode 310 and the high-frequency electrode 320 are disposed in a closed space formed by the back members 210 and 220, the shield member 230, and the insulating member 236. Therefore, the space in which the process gas supplied between the ground electrode 310 and the high-frequency electrode 320 is diffused is narrowed, and the processing efficiency is improved.

  The back member 220 is at the same potential as the high frequency electrode 320, and a high frequency is applied. Therefore, in order to efficiently introduce a high frequency into the high frequency electrode 320, the distance between the back member 220 and the high frequency electrode 320 is equal to or less than the distance from the surface of the ground electrode 310 to the surface of the high frequency electrode 320, for example, 20 mm or less. It may be necessary to make it narrower.

  FIG. 2 is an enlarged view of a main part of the plasma processing apparatus shown in FIG. This figure is a diagram for explaining the operation and effect of the high-frequency electrode 320 formed by the surface member 322 and the housing 324.

  When the object to be processed 10 is processed using the plasma processing apparatus shown in FIG. 1, a process gas is supplied to the discharge space between the high-frequency electrode 320 and the ground electrode 310. By operating the exhaust pump connected to the exhaust pipe 330, the discharge space between the high-frequency electrode 320 and the ground electrode 310 is exhausted, whereby the pressure of the discharge space between the high-frequency electrode 320 and the ground electrode 310 is controlled. Is done.

  Specifically, when the exhaust pump connected to the exhaust pipe 330 is operated, the discharge space between the high-frequency electrode 320 and the ground electrode 310 passes through the spaces 502 and 504 between the back member 210 and the high-frequency electrode 320 and the exhaust pipe 330. (Route A indicated by a dotted line in FIG. 2). Moreover, in this embodiment, the housing | casing 324 of the high frequency electrode 320 is formed from the perforated plate. For this reason, when the exhaust pump operates, the gas located in the discharge space between the high-frequency electrode 320 and the ground electrode 310 causes the opening 321 a that is a hole located on the side surface of the housing 324 and the first hollow portion 325 of the housing 324. And through the opening 321b which is a hole located on the back surface of the housing 324 (route B indicated by a one-dot chain line in FIG. 2).

  For this reason, according to this embodiment, the exhaust efficiency of the discharge space between the high frequency electrode 320 and the ground electrode 310 is improved. In particular, the back member 220 has the same potential as the high-frequency electrode 320, and this effect becomes significant when the distance between the back member 220 and the high-frequency electrode 320 needs to be reduced.

  Moreover, in this embodiment, the back surface side of the high frequency electrode 320 is formed by the housing | casing 324 formed with the perforated plate. And the hole of the housing | casing 324 is equivalent to opening 321a, 321b provided in the side surface and the back surface of the high frequency electrode 320, and the hollow part of the housing | casing 324 becomes the 1st hollow part 325 for connecting these opening. Yes. For this reason, the cost for providing the openings 321a and 321b on the side surface and the back surface of the high-frequency electrode 320 and forming the first hollow portion 325 is reduced.

  FIG. 3 is a diagram illustrating a configuration of a plasma processing apparatus according to the second embodiment. This plasma processing apparatus has the same configuration as that of the plasma processing apparatus according to the first embodiment except that the gas introduction pipe 327 is not provided and the shape of the surface member 322 is excluded.

  In the present embodiment, the high frequency electrode 320 has a function of supplying a process gas to the discharge space between the high frequency electrode 320 and the ground electrode 310, and has a shower head structure. Specifically, the surface member 322 has a hollow housing structure. A plurality of holes connected to the second hollow portion 323 which is a hollow portion of the surface member 322 are formed on the surface of the surface member 322. A process gas is supplied to the second hollow portion 323 of the surface member 322 through a gas introduction pipe 350 connected to the back surface side of the surface member 322. The process gas supplied to the second hollow portion 323 is supplied to the discharge space between the high-frequency electrode 320 and the ground electrode 310 through a hole formed in the surface of the surface member 322.

  Also in this embodiment, since the housing 324 formed of a perforated plate is provided on the back surface side of the front surface member 322, the same effect as that of the first embodiment can be obtained.

  As mentioned above, although embodiment of this invention was described with reference to drawings, these are the illustrations of this invention, Various structures other than the above are also employable.

DESCRIPTION OF SYMBOLS 10 To-be-processed object 100 Processing chamber 110 Housing | casing 210 Back surface member 212 Flat plate part 214 Convex part 220 Back surface member 222 Flat plate part 224 Convex part 230 Shield member 232 Cover part 234 Insulation member 310 Ground electrode 312 , 321b Opening 322 Surface member 323 Second hollow portion 324 Case 325 First hollow portion 326 Input portion 327 Gas introduction pipe 328 Connection plate 330 Exhaust pipe 350 Gas introduction pipe 400 High frequency power supply 410 Matching device 502 Space 504 Space

Claims (7)

A processing chamber for processing an object to be processed with plasma;
A high frequency electrode disposed in the processing chamber, to which a high frequency is applied, and a surface facing the object to be processed;
A back member provided apart from the back surface so as to cover the back surface of the high-frequency electrode, and a space between the high-frequency electrode serving as an exhaust route of the processing chamber;
With
The high-frequency electrode is
A first hollow portion provided inside the high-frequency electrode;
A first opening that is provided on a side surface of the high-frequency electrode and connects a space facing the side surface among the spaces located around the high-frequency electrode, to the first hollow portion;
A second opening provided on the back surface of the high-frequency electrode and connecting the first hollow portion to a space between the high-frequency electrode and the back member;
A plasma processing apparatus comprising: The plasma processing apparatus according to claim 1,
The plasma processing apparatus, wherein the back member is electrically connected to the high-frequency electrode. The plasma processing apparatus according to claim 1 or 2,
The high-frequency electrode is
Forming a surface side of the high-frequency electrode, and a surface member whose surface faces the object to be processed;
A housing attached to the back surface of the surface member and formed from a perforated plate,
A plasma processing apparatus in which holes located on a side surface and a back surface of the housing are the first opening and the second opening, respectively. The plasma processing apparatus according to claim 3, wherein
The plasma processing apparatus, wherein the surface member has a plate shape. The plasma processing apparatus according to claim 3, wherein
The surface member is
A second hollow portion provided inside and into which a processing gas is introduced;
A plurality of holes provided on the surface and connected to the second hollow portion;
A plasma processing apparatus comprising: A processing chamber for processing an object to be processed with plasma;
A high frequency electrode disposed in the processing chamber, to which a high frequency is applied, and a surface facing the object to be processed;
A back member provided apart from the back surface so as to cover the back surface of the high-frequency electrode, and a space between the high-frequency electrode serving as an exhaust route of the processing chamber;
A plasma processing method of processing the object to be processed using a plasma processing apparatus comprising:
The high-frequency electrode is
A first hollow portion provided inside the high-frequency electrode;
A first opening that is provided on a side surface of the high-frequency electrode and connects a space facing the side surface among the spaces located around the high-frequency electrode, to the first hollow portion;
A second opening provided on the back surface of the high-frequency electrode and connecting the first hollow portion to a space between the high-frequency electrode and the back member;
Have
A plasma processing method of exhausting the processing chamber through the first opening, the first hollow portion, and the second opening in addition to the space between the high-frequency electrode and the back member . The plasma processing method according to claim 6,
The plasma processing method, wherein the object to be processed is a substrate on which a solar cell is formed.

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