JP5914129B2 - Plasma processing equipment - Google Patents

Description

  The present invention relates to a plasma processing apparatus, and more specifically, a long sheet-like base material is wound around a drum provided in a vacuum chamber, and one of the sheet-like base materials is run while the sheet-like base material travels. It is related with what plasma-treats to the surface.

  For example, a long resin- or metal sheet-like base material has flexibility and good workability, so that a predetermined metal film or a metal compound film (metal oxide film) or the like is formed on the surface thereof. It is generally known to form an electronic component or an optical component by forming a thin film or by performing an etching process. Conventionally, a long sheet-like base material is wound around a drum that is rotatably provided in a vacuum chamber, and plasma is applied to one surface of the sheet-like base material while the sheet-like base material travels around the drum. For example, Patent Document 1 discloses that a film is formed by a plasma CVD method as a treatment.

  The above-mentioned conventional example is provided with feeding means for feeding out a sheet-like base material and winding means for winding up the processed sheet-like base material in a vacuum chamber to which a vacuum pump is connected. A discharge space (film formation chamber) for forming a film by plasma CVD using the surface portion is defined. In other words, the shower electrode is arranged so as to face the discharge space so as to face the peripheral surface portion of the drum around which the sheet-like base material is wound, and the peripheral surface portion of the drum is non-discharged on both sides in the circumferential direction of the discharge space. A ground plate curved according to the curvature of the drum is disposed so as to cover each space. And while introducing the raw material gas selected according to the composition of the thin film to be formed into the film formation chamber through the shower electrode by the gas introduction means, the high frequency power is supplied to the shower electrode by the high frequency power source for plasma generation, A plasma is formed in the discharge space to decompose the raw material gas and adhere to and deposit on one surface of the substrate to form a film.

  Here, when high frequency power is applied between the shower electrode and the ground plate to generate capacitively coupled plasma in the film forming chamber, a matching circuit is provided to match the impedance between the high frequency power source and the shower electrode. It is usual to interpose a provided matching box (see, for example, Patent Document 2). In this case, in the above-described conventional example, high-frequency power is supplied from the matching box to the shower electrode (cathode electrode) through the feeder, and the high-frequency current at this time is static from the shower electrode through the load (plasma). It flows to the ground plate to be capacitively coupled, and returns to the ground of the matching box, for example, through the wall surface of the chamber with which the ground plate is in contact.

  However, if the discharge current is collected in the matching box through the wall surface of the vacuum chamber, the impedance of the current feedback circuit becomes high (in particular, the load of the inductive component becomes large). For this reason, energy efficiency is deteriorated and high-frequency power cannot be efficiently input to the plasma, and stable discharge may not be maintained. I can't deposit well.

JP 2011-58069 A JP 2000-91317 A

  In view of the above, the present invention provides a plasma processing apparatus capable of reducing the impedance of a current feedback circuit as much as possible and allowing high-frequency power to be supplied to plasma with high energy efficiency. It is what.

  In order to solve the above problems, a long sheet-like base material is wound around a drum provided in a vacuum chamber, and plasma treatment is performed on one surface of the sheet-like base material while the sheet-like base material is running. The plasma processing apparatus of the present invention that applies the first electrode disposed opposite to the peripheral surface portion of the drum around which the sheet-like base material is wound, with the discharge space therebetween, and on both sides in the circumferential direction of the discharge space The second electrode that covers the peripheral surface portion of the drum in a non-discharge space, the high-frequency power source that supplies high-frequency power to the first electrode, and impedance matching between the high-frequency power source and the first electrode are achieved. And a matching box having a matching circuit, wherein the first electrode is detachably mounted on a wall surface of the vacuum chamber, and the first electrode is inserted through a through hole formed in the vacuum chamber and held in a predetermined position. With an electrode A matching box is integrally provided on the rear surface of the mounting direction of the rudder, and further provided with a conductive connecting member that directly connects the second electrode to the grounding matching box when the electrode holder is mounted on the wall surface of the vacuum chamber. And

  According to the present invention, since the connection member is provided, the high-frequency current when high-frequency power is supplied to the first electrode via the matching box flows to the second electrode that is capacitively coupled via the load (plasma). After that, the connecting member returns to the ground of the matching box via the shortest route and is collected without passing through the wall surface of the vacuum chamber. As a result, the impedance of the current feedback circuit can be made as small as possible and the energy efficiency is improved, so that high-frequency power can be efficiently supplied to the plasma, and a stable discharge can be realized at all times.

  By the way, since the first electrode is exposed to plasma, it is necessary to perform maintenance periodically. At this time, in the present invention, since the matching box is integrally provided in the electrode holder that holds the first electrode, the first electrode is included only by pulling out the electrode holder in the direction opposite to the mounting direction during maintenance. The electrode holder is detached from the vacuum chamber, and only the second electrode remains in the vacuum chamber. Then, after the maintenance is completed, the electrode holder is reattached. At the time of reattachment, the relative position of the first electrode is easily positioned with respect to the drum and the second electrode, and the second electrode is attached to the matching box. It is desirable to be electrically connected directly to the earth.

In the present invention, the connection member has a cylindrical outline surrounding the first electrode in the electrode holder, and extends outward in the circumferential direction on the front surface of the cylindrical connection member in the mounting direction. The second electrode has an extending portion that can be brought into surface contact, and a pin member is erected on one of the contact surfaces of the second electrode and the extending portion, and the pin is mounted on the other contact surface. If the receiving recess for fitting the member is formed, the relative position of the first electrode can be easily positioned with respect to the drum and the second electrode by simply fitting the pin member into the receiving recess. A configuration in which the two electrodes are electrically connected directly to the ground of the matching box can be realized. In addition, as a pin member, it is good to use what has what is called an other surface contact type | mold contact point with low contact resistance, and it is preferable that two or more pin members are provided.

  In the present invention, it is preferable that the contact surface between the second electrode and the extension portion further includes an endless contact having elasticity. Thereby, even when the electrode holder is repeatedly attached to and detached from the wall surface of the vacuum chamber, the contact between the contact member and the second electrode may be reliably ensured.

1 is a schematic cross-sectional view illustrating a configuration of a plasma CVD apparatus according to an embodiment of the present invention. The partial expanded sectional view shown in the state which removed the electrode holder of the plasma CVD apparatus shown in FIG. 1 from the vacuum chamber. The front view of an electrode holder.

  Hereinafter, with reference to the drawings, an embodiment of the present invention will be described with an example in which a plasma processing apparatus is a plasma CVD apparatus and a film forming process is performed on one surface of a resin sheet-like substrate S. In the following, with reference to FIG. 1, the side on which the drum is provided is down, and terms indicating directions such as up, right, and left are used.

  With reference to FIG. 1, PM is a plasma CVD apparatus as a plasma processing apparatus of this embodiment. The plasma CVD apparatus PM includes a vacuum chamber 1 to which a vacuum pump VP is connected. The inside of the vacuum chamber 1 is divided into upper and lower spaces by a partition plate 2, and a sheet-like base material S is wound around the upper space, and feeding as feeding means for feeding out the sheet-like base material S at a constant speed. A roller 3 and a winding roller 4 as a winding unit for winding the film-formed sheet-like substrate S are accommodated. In addition, since a well-known thing can utilize the mechanism until it unwinds and winds up the base material S, detailed description is abbreviate | omitted here. Then, the base material S fed from the feed roller 3 is drawn out to the lower space through the first through hole 21 formed in the partition plate 2 through the guide roller 31, and the drum disposed rotatably in the lower space. After being wound around 5, it passes through the second through hole 22 formed in the partition plate 2, and is wound around the winding roller 4 through the guide roller 41. The drum 5 may incorporate a means for heating or cooling the substrate S.

  A rectangular through hole 11 having a width (longitudinal direction in FIG. 1) longer than the length in the generatrix direction of the drum 5 is formed in the left side wall of the vacuum chamber 1 so as to surround the outer peripheral edge of the through hole 11. An electrode unit CU is detachably mounted on the outer wall surface of the vacuum chamber 1. As shown in FIG. 2, the electrode unit CU includes an electrode holder 6 formed by forming a conductive plate into a dish shape in cross-sectional view, and is illustrated on a flange 61 at the right end of the electrode holder 6 (front end in the mounting direction of the electrode holder 6). It is attached by being brought into contact with the left side wall of the vacuum chamber 1 through a vacuum seal such as an O-ring omitted and being fastened with a bolt or the like not shown in this state. And the electrode holder 6 hold | maintains the 1st electrode (cathode electrode) 7 arrange | positioned facing the surrounding surface part of the drum 5 around which the base material S is wound, having the discharge space CS.

The first electrode 7 is composed of a cylindrical member 71 having conductivity and a shower plate 72 made of the same material and attached to the right opening surface and having a plurality of gas injection ports 72a. A gas supply pipe 73 is connected to the left side. In this case, the gas supply pipe 73 extends to the wall surface of a matching box MB, which will be described later, and the gas pipe 74 from the gas source can be detachably connected. When a predetermined source gas is supplied from the gas supply pipe 73, it is once diffused in the cylindrical member 71, and the source gas is introduced into the discharge space CS through each gas injection port 72a. As the source gas, for example, when a silicon nitride film or a silicon oxide film is formed, a gas such as SiH ₄ , NH ₃ , N ₂ O, Ar, H ₂ or N ₂ is used.

  A connection member 8 is also provided concentrically around the first electrode 7 in the electrode holder 6. The connection member 8 is also composed of a cylindrical member having conductivity, and holds the first electrode 7 on the inner peripheral surface of the connection member 8 via the cylindrical insulator I. In addition, as a holding method of the 1st electrode 7, well-known methods, such as fastening with a screw and fitting, can be used. In this case, a flange 81 extending radially inward is formed at the left end of the connection member 8 and is fixed to the inner surface of the electrode holder 6 via the flange 81. As a result, the electrode holder 6 is simply mounted on the left wall surface of the vacuum chamber 1, and the discharge space CS is placed at a position facing the peripheral surface portion of the drum 5 around which the sheet-like substrate S is wound. One electrode 7, specifically, the shower plate 72 is positioned and held.

  A matching box MB is fixed to the left side surface of the electrode holder 6. A matching circuit (not shown) having a known configuration, such as a matching variable capacitor, a tuning variable capacitor, and a coil, is provided in the grounding matching box MB. A feeder line MW from the matching circuit is connected to the electrode holder 6. And connected to the first electrode 7 through the connection member 8. In this case, the power supply line MW is made of, for example, a metal bus bar, and is supported by an insulator MG that also serves as a vacuum seal provided on the electrode holder 6 and the connection member 8. The gas supply pipe 73 is also supported by the insulator MG. The matching box MB is connected to a high-frequency power supply HE having a known structure so that high-frequency power can be input to the first electrode (see FIG. 1).

  Further, in the vacuum chamber 1, a pair of upper and lower second electrodes 9 (anode electrodes) covering the peripheral surface portions of the drum 5 on both sides in the circumferential direction of the discharge space CS (in the vertical direction in FIG. 1) with a gap therebetween. ) Is provided. The second electrode 9 is made of a conductive plate material having a lateral width longer than the length of the drum 5 in the generatrix direction. The second electrode 9 is curved corresponding to the peripheral surface of the drum 5 and is not particularly illustrated and described. The insulator is fixed on the inner wall surface. In this case, the area of the second electrode 9 is set to such a value that impedance = (1 / 2πfc) when the frequency of the high-frequency power source HE is f is sufficiently small, and the area S = C / from capacitance C = S / D. In consideration of D and the like, it is set so that a large amount of return current can be recovered. In addition, the gap is a distance that does not affect the travel of the sheet-like substrate S, and the gap is shortened so that the impedance is smaller than the above-described formula gap D = C / S. Thus, the space defined by the peripheral surface of the drum 5 and the second electrode 9 becomes a non-discharge space US in which plasma does not enter when plasma is formed in the discharge space. In this case, a gap as the non-discharge space US extending in a radial direction of the drum 5 is formed between the second electrode 9 and the drum 5, so that the exhaust conductance from the discharge space CS is increased. Effective for gas atmosphere separation. When the electrode holder 6 is mounted on the left side wall of the vacuum chamber 1, the second electrode 9 is directly connected to the connection member 8.

  At the end of the second electrode 9 on the discharge space CS side, four pin members 91 extending toward the rear side in the mounting direction are erected. In this case, the pin member 91 is configured to have a so-called other surface contact type contact having a low contact resistance like a banana plug. On the other hand, the right side surface of the connecting member 8 extends toward the outer side in the circumferential direction (vertical direction in FIG. 2) and is curved corresponding to the end of the second electrode 9 on the discharge space CS side. A portion 82 is provided. The extension 82 is formed with a receiving recess 83 extending in the mounting direction (left-right direction in FIG. 2) in which the pin member 91 is fitted in correspondence with the position of the pin member 91. In addition, as shown in FIG. 3, an endless shape having elasticity on the contact surface between the extending portion 82 and the second electrode 9 is provided on the front surface in the mounting direction of the extending portion 82 of the connecting member 8. Contact 84 is provided. As such a contactor 84, for example, a rubber O-ring whose surface is covered with a mesh metal can be used.

  According to the above embodiment, since the connection member 8 is provided, the second electrode to which the high frequency current when the high frequency power is input to the first electrode via the matching box MB is capacitively coupled via the load (plasma). After flowing to 9, the connecting member 8 returns to the ground of the matching box MB by the shortest route and is collected without passing through the wall surface of the vacuum chamber 1. As a result, the impedance of the current feedback circuit can be made as small as possible and the energy efficiency is improved, so that high-frequency power can be efficiently supplied to the plasma, and a stable discharge can be realized at all times.

  By the way, in the said embodiment, since it is the structure by which the matching box MB was integrally provided in the electrode holder 6 holding the 1st electrode 7, at the time of a maintenance, just pulling out the electrode holder 6 in the direction opposite to a mounting direction, The electrode holder 6 including the first electrode 7 is detached from the vacuum chamber 1 and only the second electrode 9 remains in the vacuum chamber 1. Then, after the maintenance is completed, the relative positions of the first electrode 7 and thus the shower plate 72 are easily positioned with respect to the drum 5 and the second electrode 9 simply by fitting the pin members 91 into the receiving recesses 83 respectively. A configuration in which the second electrode 9 is electrically directly connected to the ground of the matching box MB can be realized. In addition, since the contact surface between the second electrode 9 and the extending portion 82 of the connecting member 8 is further provided with an endless contact 84 having elasticity, the electrode holder 6 is repeatedly attached to and detached from the wall surface of the vacuum chamber 1. Even if the contact between the pin member 91 and the receiving recess 83 may be insufficient, the contact 84 ensures that the contact between the contact member 8 and the second electrode 9 is ensured. It's okay.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to said thing. In the above embodiment, the plasma processing apparatus has been described as a plasma CVD apparatus. However, the present invention is not limited to this. For example, high-frequency power is input like a sputtering apparatus or an etching apparatus that forms a film by sputtering an oxide target. Thus, it can be widely applied to those subjected to plasma treatment. Moreover, in the said embodiment, although the location which forms into a film by plasma CVD method is made into an example, this invention is applicable even when it provides in multiple places around the drum.

  In the above embodiment, the example in which the connection member 8 is built in the electrode holder 6 has been described as an example. However, the present invention is not limited to this, and the electrode holder 6 may be provided outside the electrode holder 6. Moreover, the member which forms the pin member 91, the receiving recessed part 83, and the contactor 84 is not limited above, For example, you may make it form the pin member 91 in the extension part 82 side.

PM ... plasma CVD apparatus (plasma processing apparatus), 1 ... vacuum chamber, 5 ... drum, 6 ... electrode holder, 7 ... first electrode, 8 ... connecting member, 82 ... extension part, 83 ... receiving recess, 84 ... contact Child: 9 ... second electrode, 91 ... pin member, CS ... discharge space, US ... non-discharge space, HE ... high frequency power supply, MB ... matching box, S ... sheet-like substrate.

Claims (3)

A plasma processing apparatus that wraps a long sheet-like base material around a drum provided in a vacuum chamber and performs plasma treatment on one surface of the sheet-like base material while the sheet-like base material is running ,
A first electrode disposed opposite to a peripheral surface portion of a drum around which a sheet-like base material is wound, with a discharge space, and a peripheral surface portion of the drum on both sides in the circumferential direction of the discharge space. A second electrode that covers each of the first electrode, a high-frequency power source for supplying high-frequency power to the first electrode, and a matching box having a matching circuit for matching impedance between the high-frequency power source and the first electrode,
The first electrode includes an electrode holder that is detachably mounted on the wall surface of the vacuum chamber and that holds the first electrode in a predetermined position by inserting a through hole formed in the vacuum chamber. A plasma processing apparatus, wherein a matching box is provided integrally, and further includes a conductive connection member that directly connects the second electrode to a grounded matching box when the electrode holder is mounted on the wall surface of the vacuum chamber. The connecting member has a cylindrical outline surrounding the first electrode in the electrode holder, and extends to the outer side in the circumferential direction on the front surface in the mounting direction of the cylindrical connecting member. It has an extending portion that can be brought into surface contact, and a pin member is erected on one of the contact surfaces of the second electrode and the extending portion, and the pin member is fitted on one of the other contact surfaces. The plasma processing apparatus according to claim 1, wherein a receiving recess is formed.   The plasma processing apparatus according to claim 2, further comprising an endless contact having elasticity on a contact surface between the second electrode and the extending portion.

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