JP4387008B2 - High frequency electrode device for substrate processing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-frequency electrode device for a substrate processing apparatus, and in particular, supports a conductor plate for an electrode in a device that performs high-frequency discharge in a vacuum, such as a plasma CVD device, a sputtering device, an etching device, or a plasma surface treatment device. The present invention relates to a high-frequency electrode device that can effectively perform high-frequency power supply from a structure to a conductor plate.
[0002]
[Prior art]
The whole is formed of a vacuum vessel, and the vacuum vessel is evacuated to the required vacuum state with the attached vacuum pump to form the necessary vacuum conditions, and the processing target is placed on the substrate holder provided inside the vacuum vessel For example, a high-frequency electrode device is provided above the substrate, and a discharge state is generated at a high frequency fed with the introduced process gas, plasma is generated, radicals in the plasma are extracted, and the above-described Various substrate processing apparatuses configured to vacuum process a substrate are known. In order to perform vacuum processing on a substrate using a high frequency, it is important to effectively supply a high frequency to the electrode on the high frequency application side and to securely connect the ground (ground) side electrode to the ground.
[0003]
FIG. 4 shows a plasma CVD apparatus for forming a film on a substrate as an example of the substrate processing apparatus. In FIG. 4, a chamber 101 that forms a substrate film formation space includes a substrate holder 102 on the inside lower side and an electrode device 103 on the inside upper side. The chamber 101 is configured as a vacuum container made of a metal material, and includes an exhaust mechanism (not shown) for exhausting the internal space to a required vacuum state. The substrate holder 102 is fixed to the bottom wall 101a of the chamber 101 and is grounded. The substrate holder 102 and the chamber 101 are held at ground potential. A substrate 104 is placed on the upper surface of the substrate holder 102. The electrode device 103 is provided so as to face the substrate 104. The electrode device 103 is fixed to the upper wall 101 b of the chamber 101 via an insulator 105. The electrode device 103 includes a flat conductor plate 106 disposed so as to face the substrate 104, and a support structure 107 made of a conductive material (such as aluminum) that fixes and supports the conductor plate 106. The A large number of holes 108 are formed in the entire surface of the conductor plate 106. A space 109 is formed inside the electrode device 103, and a gas for generating plasma is introduced into the space 109. The conductor plate 106 is fixed to the lower surface of the support structure 107 so as to cover the space 109. A high frequency is supplied to the conductor plate 106 from the high frequency power supply 110 provided outside via the support structure 107. In the electrode device 103 described above, a gas is introduced into the space 109, and the gas is supplied to the front space of the substrate 104 through a large number of holes 108 formed in the conductor plate 106. Further, between the conductor plate 106 and the substrate holder 102, a high frequency is supplied to the conductor plate 106 to generate a discharge and generate plasma. A plasma CVD action is generated in the front space of the substrate 104 based on the generated plasma and a reaction gas supplied separately, and film formation is performed on the surface of the substrate 104.
[0004]
The substrate holder 102 incorporates a heater 111 and acts as a counter electrode corresponding to the conductor plate 106 acting as an electrode plate of the electrode device 103, and functions as a heating susceptor. When the substrate 104 is placed on the substrate holder 102 and film formation is performed on the surface of the substrate, heat is generated from the substrate holder 102 in order to keep the substrate at a required temperature state. The conductor plate 106 of the electrode device 103 directly receives radiant heat from the substrate holder 102. Further, the conductor plate 106 receives heat from the discharge.
[0005]
Although FIG. 4 does not show the fixing structure of the conductor plate 106 in the support structure 107, the fixing structure of the conductor plate 106 attached to the support structure 107 will be described in detail with reference to FIGS. .
[0006]
In the fixing structure shown in FIG. 5, the conductor plate 106 is fixed to the lower surface of the support structure 107 by coupling the screw 113 to the screw hole 114 of the support structure 107 through the hole 112 formed in the conductor plate 106. . A plurality of places fixed by the screws 113 are provided. In the fixing structure shown in FIG. 6, in the fixing structure using the screw 113 and the screw hole 114 of the support structure 107 similar to those shown in FIG. 115 is sandwiched. The conductor plate 106 is strongly pressed against the lower surface of the support structure 107 by the elasticity of the disc spring 115. Further, according to this structure, it is possible to adjust the pressing force of the conductor plate 106 to the support structure 107. In FIG. 7, in the fixing structure using the screw 113 similar to that shown in FIG. 5 and the screw hole 114 of the support structure 107, the diameter of the hole 112 of the conductor plate 106 is increased, and the gap between the screw 113 and the conductor plate 106 is increased. A spacer 116 is interposed. Since the axial length of the spacer 116 is set to be slightly larger than the thickness of the conductor plate 106, a gap 117 is generated between the conductor plate 106 and the support structure 107.
[0007]
[Problems to be solved by the invention]
In the electrode apparatus 103 of the substrate processing apparatus shown in FIG. 4, the fixing structure between the conductor plate 106 and the support structure 107 that supports the conductor plate 106 has the following problems.
[0008]
If the electrical connection by the contact between the conductor plate 106 and the support structure 107 is insufficient, not only the high-frequency power cannot be efficiently transmitted to the conductor plate 106 via the support structure 107 but also uneven discharge and unevenness of the discharge. This will have a significant impact on processing quality. Therefore, as shown in FIG. 5, a structure is adopted in which the conductor plate 106 is fixed to the support structure 107 by screws. According to this fixing structure, the conductor plate 106 and the support structure 107 are firmly coupled to form a good contact state, and the electrical connection is improved. However, this fixing structure causes another important problem due to the extension of the conductor plate 106. In other words, the conductor plate 106 is heated by discharge or heated from the opposing heating susceptor (counter electrode with a heater) such as thermal radiation or heat conduction, so that the temperature rise is large and the radial extension occurs in particular. Since the structure 107 is not exposed to the discharge and the radiant heat from the heating susceptor is also separated by the conductor plate 106, the temperature rise is small compared to the conductor plate 106. Therefore, according to the structure in which the conductor plate 106 is fixed with the screw 113 shown in FIG. 5, the extension of the conductor plate 106 loses the escape field, and the conductor plate 106 is curved. If the conductor plate 106 is curved, the distance to the counter electrode changes, causing problems such as unstable discharge and variations in the film quality of the substrate 104.
[0009]
In the fixing structure shown in FIG. 6, the conductor plate 106 is pressed against the support structure 107 by the disc spring 115. By adjusting the degree of screwing of the screw 113, the pressing force of the conductor plate 106 can be adjusted using the disc spring 115. When the pressing force by the disc spring 115 is increased, the contact state between the conductor plate 106 and the support structure 107 is improved and the high-frequency energization state is improved, but conversely, as described above, the conductor plate 106 is bent (warped or the like). ) Problem occurs. If the pressing force by the disc spring 115 is weakened, the problem of bending of the conductor plate 106 is solved, but the contact state becomes poor and the electrical connection related to high-frequency energization becomes poor.
[0010]
In the fixing structure shown in FIG. 7, a spacer 116 is provided in a portion joined by the screw 113 to form a space in the radial direction, and when the conductor plate 106 extends in the radial direction due to heat, it is released and no bending occurs. However, since the gap 117 is formed between the conductor plate 106 and the support structure 107, the electrical connection is insufficient.
[0011]
As described above, regarding the fixing structure of the conductor plate 106 and the support structure 107 in the electrode device 103, particularly when a high frequency of, for example, 60 MHz or more is supplied to the conductor plate 106 via the support structure 107, It has been a difficult task to make both the electrical connection state of the support structure 107 good and ensuring the radial escape due to the thermal expansion of the conductor plate 106.
[0012]
In the above description, problems have been pointed out particularly with respect to the electrode structure on the high frequency application side in the electrode device. However, as described above, it is also important to securely connect the ground side electrode to the ground. The same problem is pointed out for the side electrode.
[0013]
An object of the present invention is to solve the above-mentioned problem. In an apparatus such as a plasma CVD apparatus, a sputtering apparatus, an etching apparatus, or a plasma surface treatment apparatus that performs substrate processing using discharge using high frequency in a vacuum, a conductor An object of the present invention is to provide a high-frequency electrode device capable of improving the electrical connection relationship between a plate and its support structure and preventing the occurrence of a curved state due to thermal expansion of a conductor plate.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, the high-frequency electrode device of the substrate processing apparatus according to the present invention is configured as follows.
The high-frequency electrode device according to the present invention is arranged in a vacuum in a substrate processing apparatus as a precondition, and more specifically, a conductor plate arranged on the substrate side and the conductor plate with screws. For example, a space for introducing a gas is formed between the conductor plate and the support structure, and the conductor plate is externally connected via the support structure. A high frequency power is supplied from a high frequency power source, and a discharge is generated using the high frequency to process the substrate. The high frequency fed to the conductor plate of the electrode device is preferably a high frequency of 60 MHz or more. In addition, about the range of a high frequency, the high frequency used conventionally conventionally lower than 60 MHz, for example, 13.56 MHz may be sufficient.
Further, in the above-described high-frequency electrode device, in the conductor plate fixing portion provided with a screw, a screw is provided in a hole formed in the conductor plate via a spacer, and the conductor plate is interposed between the hole and the spacer in the radial direction of the hole. And a gap is formed between the conductor plate and the support structure by making a length in the axial direction of the spacer longer than a thickness of the conductor plate. In addition to the conductor plate fixing portion, a groove formed on either one of the opposing surfaces of the conductor plate and the support structure for supplying a high frequency to the conductor plate is provided between the plate and the support structure. An energizing contact portion formed of a conductor having a spring property is provided in the thickness direction of the conductor plate disposed in the groove.
In the above-described present invention, in an apparatus for forming, etching, or surface-treating the surface of a substrate using high-frequency discharge in a vacuum, an electrode conductor plate for an electrode device to which a high frequency is applied and its support structure In addition to the fixing portion between the conductor plate and the support structure, a current-carrying contact portion for high-frequency current conduction is provided in the body-fixing structure. Thereby, it is possible to achieve two technical problems that are contradictory to improving the electrical connection relationship between the conductor plate and the support structure and preventing the occurrence of a curved state due to thermal expansion of the conductor plate.
Further, by using a conductor having spring properties, it is possible to reliably obtain electrical contact between the conductor plate and the support structure.
Further, in the above configuration, the structure portion including the conductor plate and the support structure is provided on the high-frequency power supply side, but instead, the structure portion including the conductor plate and the support structure can be provided on the ground side. Also in this case, a conductor plate fixing part and a current-carrying contact part are provided between the conductor plate and the support structure of the structural part, and the conductor plate is grounded via a current-carrying contact part between the support structure and the conductor plate. Connected securely.
In each of the above configurations, more preferably, the groove and the conductor are configured to have a ring shape. The ring-shaped groove and the conductor are provided around the gas introduction space.
Furthermore, in each of the above-described configurations, the energization contact portion is provided at a plurality of positions with a gap around the gas introduction space. The shape of the current-carrying contact portion does not need to be a continuously connected ring, but can be a discontinuous shape as long as high-frequency can be effectively supplied or electrical connection can be reliably made to the ground. Can be provided in a distributed manner.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
[0016]
FIG. 1 is a partial longitudinal sectional view showing the structure of a main part of a high-frequency electrode device according to the present invention, and FIG. 2 is a bottom view of the electrode device. The overall configuration of the high-frequency electrode device and the arrangement structure in the substrate processing apparatus are the same as those described with reference to FIG. 4, and will be described with reference to FIG. 1 and 2, elements that are substantially the same as those described in FIGS. 4 and 5 to 7 are denoted by the same reference numerals. FIG. 1 and FIG. 2 show a configuration of the fixing portion 11 and the electrical contact portion 12 between the conductor plate 106 and the support structure 107, which is a characteristic configuration of the high-frequency electrode device according to the present invention. As described with reference to FIG. 4, the conductor plate 106 is attached to the lower surface of the support structure 107 so as to cover the space 109 into which the gas formed in the support structure 107 is introduced in the electrode device 103. It is fixed to. As shown in FIGS. 1 and 2, a large number of holes 108 are formed on the entire surface of the conductor plate 106 corresponding to the space 109. In FIG. 2, only a part of the many holes 108 is shown for convenience. The conductor plate 106 is fixed to the lower surface of the support structure 107 using a coupler such as a screw 113. The fixing portion 11 is provided at a plurality of locations around the space 109, preferably at regular intervals. In FIG. 2, a plurality of fixing portions 11 are shown. In FIG. 1, one fixed portion 11 and the peripheral portion including the electrical contact portion 12 are enlarged.
[0017]
In the substrate processing apparatus shown in FIG. 4, the frequency of the high frequency fed from the high frequency power supply 110 to the electrode device 103 is preferably a high frequency of 60 MHz or more. When such a high frequency is supplied to the conductive plate 106 as the electrode plate via the support structure 107 in the electrode device 103, discharge occurs in relation to conditions such as vacuum conditions, temperature conditions, introduction of plasma generating gas, and the like. Is generated and a plasma is generated.
[0018]
As shown in FIGS. 1 and 2, the electrode plate 103 has a structure portion (fixing portion 11) for fixing the conductor plate 106 to the support structure 107, and the support structure 107. The electrical contact portion (energizing contact portion) 12 for applying a high frequency to the conductor plate 106 is provided separately as a different portion.
[0019]
The fixing portion 11 is formed with a hole 13 having a large diameter in the conductor plate 106, and on the other hand, a screw hole 14 is formed on the lower surface of the support structure 107, a spacer 15 is disposed in the hole 13, and a screw 16 is interposed via the spacer 15. Is screwed into the screw hole 14. The length of the spacer 15 in the axial direction is longer than the thickness of the conductor plate 106, and the flange portion of the spacer 15 is in contact with the lower surface of the conductor plate 106. Therefore, the fixing structure in the fixing portion 11 is not a structure in which the conductor plate 106 is pressed strongly against the lower surface of the support structure 107 and is in contact with the lower surface of the support structure 107, but is suppressed to the extent that the conductor plate 106 is separated from the support structure 107. It is. The fixing portion 11 employs a screwing structure, but is not a structure for obtaining an action of electrically contacting the conductor plate 106 and the support structure 107. Therefore, a desirable gap 17 is formed between the conductor plate 106 and the support structure 107 in the fixed portion 11. The hole 13 is formed to have a large diameter, and a gap 18 is formed in the radial direction between the outer surface of the spacer 15 and the inner surface of the hole 13. According to such a structure of the fixing portion 11, when the conductor plate 106 receives heat and expands in the radial direction, the conductor plate 106 can slide at the fixing portion 11, and a curved state (warp or the like) does not occur. . On the other hand, since the fixed portion 11 cannot obtain a sufficient contact state as an electrical connection portion, it cannot be operated as a high-frequency energizing portion.
[0020]
High-frequency power supply from the support structure 107 to the conductor plate 106 is performed via the electrical contact portion 12 described above. In this example, the electrical contact portion 12 is configured by forming a groove 21 on the lower surface of the support structure 107 and providing a contact member 22 in the groove 21. The groove 21 is formed in a ring shape around the space 109, and the contact member 22 also has a ring shape. The contact member 22 has a spring property that tends to extend in the depth direction of the groove 21 (or the thickness direction of the conductor plate 106), and is formed of a conductive material. In the example shown in FIG. 1, the contact member 22 has a spring property in the vertical direction. Therefore, the contact member 22 always contacts the conductor plate 106 and the bottom of the groove 21 of the support structure 107, thereby supporting the support conductor plate. Good electrical contact is made between 106 and support structure 107. In this electrical contact state, since the groove 21 and the contact member 22 have a ring shape, the electrical contact portion 12 that is formed all around the space 109 and can perform good high-frequency energization is formed. The Further, the amount of spring deformation of the contact member 22 is set moderately and can be slightly deformed in the extending direction of the conductor plate 106, so that the sliding action is obstructed when the conductor plate 106 extends in the radial direction due to thermal expansion. Never become.
[0021]
As described above, the structure of the fixing portion 11 and the electrical contact portion 12 provided between the conductor plate 106 and the support structure 107 prevents warping or the like caused by escaping the extension of the conductor plate 106 and provides good electrical performance. It is possible to achieve both connection and connection.
[0022]
In the above-described embodiment, the structure is shown in which the groove 21 is provided in the support structure 107 and the contact member 22 is incorporated therein. However, the groove may be on the conductor plate 106 side, and the cross-sectional shape of the groove may be It is not limited to a rectangle like this embodiment, It can also be made into a semicircle shape. Furthermore, it is also possible to configure such that the above-mentioned groove is not provided, and the contact member having the spring property as described above is simply sandwiched between the conductor plate 106 and the support structure 107.
[0023]
As the contact member 22 that creates a sufficient electrical contact state for supplying the high frequency power supplied from the high frequency power supply 110 to the conductor plate 106 from the support structure 107, any member can be used as long as it is a member that provides the same action. For example, a conductive sealing material that seals electromagnetic waves and the like as described in Japanese Patent Publication No. 7-87275 can be applied. The ring-shaped contact member 22 is preferably formed of a string-shaped wire. The forms of various ring-shaped contact members are shown in FIGS. The contact member 22A is formed by winding a metal wire in a coil shape. The contact member 22B is formed by winding a metal foil (or a metal thin plate) in a coil shape. The contact member 22C is formed by winding a metal foil (or a metal thin plate) into a cylindrical shape. The contact member 22D is formed such that a metal foil (or a metal thin plate) having a rectangular shape with a U-shaped cross section is cut to give the spring property. The contact member 22E is formed by shaping a thin metal wire so that the cross section is rectangular (square tube shape). The contact member 22F is formed by knitting a thin metal wire into a cylindrical shape. In addition, it is also possible to use conductive elastomer material instead of metal.
[0024]
The above-described embodiment can be modified as follows. In the present embodiment, an example of an electrode device on the side to which a high frequency is applied has been shown. However, a similar structure can be adopted even when the ground side electrode is composed of an electrode conductor plate and a support structure that supports the electrode conductor plate. It is obvious that it is effective. That is, the conductor plate is reliably connected to the ground via the electrical contact portion with the support structure.
[0025]
In the electrode device 103 according to the above embodiment, the substrate processing apparatus is a plasma CVD apparatus, and the film formation space for performing CVD film formation on the substrate and the plasma generation space for generating plasma are separated. Of course, the present invention can also be applied to a configured apparatus. In the configuration example of this device, the space 109 formed in the electrode device 103 is used as a space for generating plasma, a plasma generating gas is introduced into the space 109, and a high frequency is supplied to the conductor plate 106 to supply the space 109. A discharge is generated to generate plasma, radicals and the like are taken out from the plurality of holes 108 formed in the conductor plate 106, a reaction gas is introduced into the front space of the substrate, and a film is deposited on the surface of the substrate by the CVD action. . In this example, the conductor plate normally acts as an electrode on the ground side, and the conductor plate is reliably connected to the ground via the electrical contact portion and the support structure. Further, even when the conductor plate expands due to heat and extends in the radial direction, it is possible to prevent warping from occurring due to the structure of the fixing portion 11 described above.
[0026]
Further, in the above-described embodiment, the groove 21 and the contact member 22 are formed in a ring shape, so that the electrical contact portion 12 is formed in a ring shape all around the space 109. However, the electrical contact portion 12 is necessary. Since it is sufficient that high-frequency energization can be performed, it is not always necessary to form the electrical contact portion 12 in a ring shape. If sufficient high-frequency energization sufficient to stabilize the discharge can be performed, for example, a plurality of gap portions can be provided in the middle of the ring-shaped electrical contact portion 12, or the electrical contact portion 12 can be provided. Can also be provided in a distributed manner.
[0027]
The frequency of the high frequency fed to the electrode device 103 is not limited to the above-described frequency of 60 MHz or more. For example, even if it is applied to a high frequency of 13.56 MHz that has been conventionally used, it goes without saying that the same effect as described above is exhibited.
[0028]
【The invention's effect】
As is apparent from the above description, according to the present invention, the extension of the conductor plate is allowed in the high-frequency application side or the ground-side high-frequency electrode device comprising the conductor plate and the support structure that fixes the conductor plate with a coupler. And a conductive contact portion for energizing a high frequency to the conductor plate are provided separately, so that a good electrical connection between the conductor plate as an electrode plate and its support structure and the extension due to the thermal expansion of the conductor plate It is possible to achieve both of ensuring the escape of the vacuum and to improve the vacuum processing quality by preventing discharge stability and warpage.
[Brief description of the drawings]
FIG. 1 is a partial longitudinal sectional view showing a main structure of a high-frequency electrode device according to the present invention.
FIG. 2 is a bottom view of the high-frequency electrode device according to the present invention.
FIG. 3 is a partial perspective view showing various examples of a contact member.
FIG. 4 is a longitudinal sectional view showing an example of a substrate processing apparatus to which a conventional and the present invention is applied.
FIG. 5 is a partial longitudinal sectional view showing a first example of a conventional fixing structure.
FIG. 6 is a partial longitudinal sectional view showing a second example of a conventional fixing structure.
FIG. 7 is a partial longitudinal sectional view showing a third example of a conventional fixing structure.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Fixing part 12 Electrical connection part 15 Spacer 16 Screw 17 Gap 21 Groove 22, 22A-22F Electrical contact member 103 Electrode device 104 Substrate 106 Conductor plate 107 Support structure 109 Space 110 High frequency power supply

Claims (4)

A conductor plate disposed on the substrate side and a support structure that supports the conductor plate by fixing the conductor plate with screws, and gas is introduced between the conductor plate and the support structure. A high-frequency electrode of a substrate processing apparatus for processing the substrate is formed, and a high-frequency power is supplied to the conductor plate from an external high-frequency power source via the support structure, and discharge is generated using the high frequency. In the device
In the screw conductor plate fixing portion provided via a spacer to the holes formed in the conductor plate provided with the screw, the said conductive plate between the said hole spacer in the radial direction of the hole A gap that allows radial extension is formed, and a gap is formed between the conductor plate and the support structure by making the axial length of the spacer longer than the thickness of the conductor plate; ,
Any one of the opposing surfaces of the conductive plate and the support structure for energizing the high frequency to the conductive plate separately from the conductive plate fixing portion between the conductive plate and the support structure. An energizing contact portion is provided that is formed by a groove formed in the conductor plate and a conductor having a spring property in the thickness direction of the conductor plate disposed in the groove;
A high-frequency electrode device for a substrate processing apparatus.   A structure portion composed of the conductor plate and the support structure is provided on the ground side instead of being provided on the high-frequency power supply side, and the conductor plate fixing portion and the energization are provided between the conductor plate and the support structure of the structure portion. 2. The high-frequency electrode device for a substrate processing apparatus according to claim 1, wherein a contact portion is provided, and the conductor plate is connected to ground via the energization contact portion of the support structure.   The high-frequency electrode device for a substrate processing apparatus according to claim 1, wherein the groove and the conductor have a ring shape.   4. The high-frequency electrode device for a substrate processing apparatus according to claim 1, wherein a plurality of the current-carrying contact portions are provided at intervals around the gas introduction space.

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