JP2010285667A - Plasma cvd apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent warpage and distortion of a cathode electrode in a plasma CVD processing apparatus. <P>SOLUTION: A plasma CVD apparatus 100 for processing a substrate by producing plasma of a processing gas is provided with a processing container 103 for receiving the substrate and a plural sets of a cathode electrode 101 and an anode electrode 102 which are arranged in the processing container 103. The cathode electrode 101 comprises a backing plate 3 and a shower plate 2. A middle fastening portion 6 which contacts with the backing plate 3 is formed in the shower plate 2. Therefore, the heat of the plasma applied to the shower plate 2 is transmitted to the backing plate 3 through the middle fastening portion 6, thereby improving the uniformity of the temperature of the cathode electrode 101. Consequently, the warpage and distortion of the cathode electrode 101 are prevented. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a plasma CVD apparatus for processing a substrate by converting a processing gas into plasma.

  Conventionally, in a film forming process or an etching process, for example, a plasma CVD apparatus (plasma processing apparatus) using a microwave or a high frequency is used.

  For example, Patent Document 1 discloses a plasma CVD (plasma-enhanced chemical vapor deposition) apparatus for forming a thin film on a substrate. The plasma CVD apparatus of Patent Document 1 includes a cathode electrode connected to a high-frequency power source and a susceptor (anode electrode) that supports the substrate so as to face the cathode electrode. The cathode electrode is also connected to a gas introduction system and serves as a processing gas supply member. In the plasma CVD apparatus of Patent Document 1, when a processing gas is supplied from a gas introduction system to a processing chamber via a cathode electrode and a high frequency voltage is applied to both electrodes, plasma generated between the cathode electrode and the anode electrode is processed. The gas is activated, and the activated processing gas reaches the substrate on the anode electrode to form a thin film.

  In general, a cathode electrode serving as a processing gas supply member is composed of a backing plate (support plate) and a shower plate so as to have a buffer space therein. The processing gas supplied to the cathode electrode is supplied to the buffer space, and then supplied to the processing chamber through a plurality of openings provided in the shower plate. The buffer space can uniformly supply a processing gas from the shower plate to the substrate and perform uniform plasma processing.

  In recent years, plasma processing apparatuses capable of processing a plurality of substrates simultaneously have been proposed. For example, Patent Document 2 discloses a plasma processing apparatus having a multi-electrode structure. In this apparatus, a plurality of cathode-anode electrode pairs each composed of a cathode electrode and an anode electrode are arranged in one chamber.

  By the way, in the plasma CVD apparatus such as Patent Document 1, when forming a thin film, the thin film material adheres not only to the target substrate but also to the surface of the cathode electrode. As the deposited thin film material accumulates, it peels off from the surface of the cathode electrode, and falls on the surface of the substrate to cause a defective product. For this reason, it is necessary to periodically remove the thin film material adhering to the cathode electrode. For this removal, dry cleaning is generally used. In dry cleaning, a cleaning gas is introduced into a processing chamber and activated by plasma, as in the case of thin film formation, so that the thin film material attached to the cathode electrode is removed by plasma etching.

JP 2008-189964 A (released on August 21, 2008) JP 2006-120926 A (published May 11, 2006)

  In the plasma processing apparatus disclosed in Patent Document 2, it is preferable to arrange many cathode-anode electrode pairs in one chamber in order to increase the number of substrates that can be processed at one time. Here, the cathode electrode and the anode electrode expose the surfaces facing each other and the surfaces opposite to the surfaces, that is, the front and back surfaces, in the gas phase in the processing chamber.

  However, when a plasma processing apparatus having such an electrode structure is used as a plasma CVD apparatus for forming a thin film, the cathode electrode is likely to be warped or distorted, which causes variations in the characteristics of the film to be formed. There is a problem of end.

  Further, in the plasma CVD apparatus as described above, an unnecessary deposited film deposited in a processing chamber (for example, an electrode) is removed by dry cleaning using, for example, fluorine-based gas plasma. When plasma is applied at a high output during film formation, film quality generally deteriorates. On the other hand, since a thin film is not deposited at the time of dry cleaning, there is no problem with the film quality, and it is desirable to apply plasma with a high output to increase the processing capability. For this reason, the temperature rise of the electrode due to the heat of plasma becomes larger during dry cleaning than during film formation. Therefore, at the time of dry cleaning, the problem that the entire cathode electrode is warped due to the thermal stress due to the temperature rise, and the problem of local distortion are likely to occur.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a plasma CVD processing apparatus capable of stably performing thin film formation and dry cleaning by suppressing warping or distortion of electrodes. It is in.

  The present inventors have intensively studied to solve the above problems. Specifically, the present inventors considered as follows.

  In a plasma CVD apparatus, of the cathode electrode, the shower plate facing the plasma generation region is easily affected by the heat of the plasma, while the backing plate, that is, the support plate, is not in contact with the discharge surface. It is susceptible to controlled temperature at the anode electrode. Therefore, in the cathode electrode, a temperature difference is generated between the shower plate and the backing plate. The present inventors considered that the expansion amount of the shower plate and the backing plate was different due to this temperature difference, which caused warpage of the cathode electrode.

  In addition, when the present inventors dry-clean the plasma CVD apparatus, if the high frequency power is set to a high power setting, the temperature on the shower plate side rises due to the high power plasma, and the temperature between the shower plate and the backing plate increases. It has been found that a temperature difference occurs particularly. Furthermore, it has been found that the temperature difference is more caused in the vicinity of the inlet of the cleaning gas to the cathode electrode due to the influence of the temperature of the introduced gas, and the cathode electrode is considered to be locally distorted.

  Therefore, the present inventors have found that the above warpage and distortion can be suppressed by suppressing the temperature difference between the shower plate and the backing plate, and have completed the present invention.

  That is, the plasma CVD apparatus according to the present invention is a plasma CVD apparatus for forming a film on a substrate by converting a processing gas into a plasma in a processing chamber, wherein the front and back surfaces are exposed to the gas phase and face each other in the processing chamber. And an electrode pair for converting the processing gas into plasma, and at least one of the electrodes is provided by the support plate and the shower plate having a plurality of through holes provided in the electrode. A buffer chamber for supplying the processing gas to the processing chamber is configured, and the support plate and the shower plate are connected by at least one intermediate fastening portion.

  As described above, the plasma CVD apparatus according to the present invention forms a thin film on the surface of a substrate such as glass or silicon by converting the processing gas into plasma in a processing chamber isolated from an outside air environment such as vacuum. .

  The electrodes constituting the electrode pair are such that the surfaces facing each other and the opposite surfaces, that is, the front and back surfaces, are exposed to a gas phase meaning a processing gas atmosphere or a vacuum atmosphere in the processing chamber, and are opposed to each other in the processing chamber. Are arranged. Further, the high-frequency power is applied to the electrodes, and the processing gas released into the processing chamber is converted into plasma between the electrodes.

  At least one of the electrodes has a buffer chamber for supplying the processing gas to the processing chamber by a support plate, also called a backing plate, and a shower plate having a plurality of through holes for supplying gas into the processing chamber. Constitute. The electrode is connected to, for example, a gas supply system, and the processing gas supplied from the gas supply system is discharged into the processing chamber through the buffer chamber and a plurality of holes formed in the shower plate.

  The support plate and the shower plate are connected by at least one intermediate fastening portion.

  The electrode constituting the buffer chamber may be a cathode electrode, an anode electrode, or both electrodes in the electrode pair.

  In the above configuration, of the shower plate and the support plate, the shower plate faces the plasma generation region, and the support plate is disposed on the opposite side across the buffer chamber. For this reason, during the thin film processing in the plasma CVD apparatus, the heat of the plasma is first transmitted to the shower plate. At this time, since the shower plate and the support plate are connected by the intermediate fastening portion, the heat transmitted to the shower plate is transmitted to the support plate via the intermediate fastening portion. Therefore, it is suppressed that a temperature difference arises between a shower plate and a support plate.

  The intermediate fastening portion may be a separate member from the shower plate and the support plate, but is formed as the same member on one surface of the shower plate and the support plate among the opposing surfaces of the shower plate and the support plate. The structure formed in contact with the surface is preferable from the viewpoint of heat conduction.

  Further, although one intermediate fastening portion may be provided, it is preferable that a plurality of intermediate fastening portions are formed from the viewpoint of the amount and uniformity of heat conduction because the number of heat conduction portions increases.

  According to the said structure, the difference of the expansion amount by the temperature difference of a shower plate and a support plate is suppressed, and the curvature and distortion of the electrode which comprises a buffer chamber among the said electrode pairs can be prevented. Therefore, it is possible to provide a plasma CVD apparatus that can stably perform thin film formation and dry cleaning.

  In the plasma CVD apparatus according to the present invention, a plurality of the electrode pairs may be arranged side by side in the processing chamber.

  According to the above configuration, the plasma CD apparatus according to the present invention can be a plasma CVD having a multi-electrode structure. Also in this configuration, warping and distortion of the electrode connected to the gas supply unit in the electrode pair can be suppressed, and thin film formation and dry cleaning can be performed stably.

  In the plasma CVD apparatus according to the present invention, the electrode constituting the buffer chamber is preferably a cathode electrode.

  In general, in a plasma CVD apparatus, since a substrate is mounted on an anode electrode, cooling water, a heater, and the like for temperature control are arranged on the anode electrode. In this case, since the cathode electrode has a simpler configuration than the anode electrode, the plasma CVD apparatus according to the present invention can be more easily configured.

  In the plasma CVD apparatus according to the present invention, it is preferable that a rib-shaped outer periphery fastening portion in contact with the support plate is formed on an outer periphery of the surface of the shower plate facing the support plate.

  According to the said structure, the intensity | strength of the outer peripheral part of a shower plate improves with the rib formed in the outer peripheral part of a shower plate. As a result, for example, even if a local temperature difference occurs in the vicinity of the processing gas inlet in the electrode constituting the buffer chamber, the cathode electrode can be prevented from being locally distorted.

  In the plasma CVD apparatus according to the present invention, the intermediate fastening portion is preferably formed integrally with the shower plate.

  According to the said structure, the intensity | strength of a shower plate can be improved more. As a result, even if stress is concentrated on the shower plate, warping of the shower plate can be suppressed, and consequently, warping and distortion of the electrodes constituting the buffer chamber in the electrode pair can be further suppressed.

  In the plasma CVD apparatus according to the present invention, in the shower plate, the intermediate fastening portion is preferably formed in a region between the holes.

  Thereby, the intermediate fastening portion does not block the plurality of holes communicating the space inside the cathode electrode and the processing chamber. Therefore, it is possible to avoid the passage of the processing gas through the hole.

  In the plasma CVD apparatus according to the present invention, the ratio of the total area of the contact surface where the shower plate or the support plate contacts the plurality of intermediate fastening portions to the area of the bottom surface of the buffer chamber is the electrode pair. The value divided by the input power density is preferably 5 or more.

  According to the said structure, the heat of a shower plate can be more effectively transmitted with respect to a support plate via an intermediate | middle fastening part. Therefore, it can suppress more that a temperature difference arises between a shower plate and a support plate.

  In the plasma CVD apparatus according to the present invention, at least one electrode constituting the buffer chamber is constituted by a support plate and a shower plate, and the shower plate and the support plate are connected by at least one intermediate fastening portion. Therefore, it is possible to provide a plasma CVD apparatus capable of efficiently conducting heat through the intermediate fastening portion and stably performing thin film processing and dry cleaning.

It is sectional drawing which shows the cathode electrode of the plasma CVD apparatus which concerns on one Embodiment of this invention. 1 is a cross-sectional view schematically showing a plasma CVD apparatus according to an embodiment of the present invention. It is sectional drawing which shows schematically the plasma CVD apparatus which concerns on other embodiment of this invention. It is sectional drawing which shows schematically the plasma CVD apparatus which concerns on other embodiment of this invention. It is sectional drawing which shows schematically the plasma CVD apparatus which concerns on other embodiment of this invention. It is a disassembled perspective view which shows the shower plate of a cathode electrode partially. (A) and (b) are sectional drawings which show roughly the whole structure of a cathode electrode. (A) is sectional drawing which expands and shows an intermediate | middle fastening part, (b) is sectional drawing which expands and shows an outer periphery fastening part. It is sectional drawing which shows the cathode electrode in other embodiment. (A) It is a graph which shows the relationship between a cathode deformation amount and an intermediate | middle fastening part area ratio, (b) It is a graph which shows the relationship between a cathode temperature difference and an intermediate | middle fastening part area ratio. It is a graph which shows the film thickness uniformity formed into the board | substrate. It is a figure for demonstrating a measurement location.

(Configuration of plasma CVD apparatus 100)
The embodiment of the present invention will be described below with reference to FIGS.

  First, a schematic configuration of the plasma CVD apparatus 100 according to the present embodiment will be described with reference to FIG.

  FIG. 2 is a cross-sectional view illustrating a schematic configuration of the plasma CVD apparatus 100. As shown in FIG. 2, a sealable processing container (processing chamber) 103 that accommodates a substrate as an object to be processed, and a cathode that is arranged in the processing container 103 and includes a cathode electrode 101 and an anode electrode 102. And an anode electrode pair.

  The processing container 103 is made of, for example, stainless steel and has a configuration that can be evacuated. The inner wall surface of the processing container 103 is covered with a protective film such as alumina, and the processing container 103 is electrically grounded.

  An exhaust pipe (not shown) is provided at the bottom of the processing vessel 103, and an exhaust device such as a vacuum pump is connected to the end of the exhaust pipe. The exhaust device can appropriately depressurize the atmosphere in the processing container 103, and can be set to, for example, 10 Pa or more and 6000 Pa or less.

  In the cathode-anode electrode pair, each of the cathode electrode 101 and the anode electrode 102 has a plate shape and is arranged to face each other. A substrate is disposed between the cathode electrode 101 and the anode electrode 102. The substrate is not particularly limited as long as the plasma CVD apparatus 100 is an object to be processed, and examples thereof include a glass substrate.

  The anode electrode 102 serves as a mounting table for mounting the substrate thereon, and is disposed below the paired cathode electrodes 101. The anode electrode 102 is made of a material having conductivity and heat resistance, such as stainless steel, aluminum alloy, and carbon. The dimension of the anode electrode 102 may be designed to an appropriate value in accordance with the dimension of the substrate.

  Further, the anode electrode 102 incorporates temperature stabilizing means such as a heater and a cooling facility, and the temperature is controlled to room temperature (for example, 25 ° C.) to 300 ° C. by the temperature stabilizing means. For this reason, on the substrate on the anode electrode 102, the temperature rise due to the heat of the generated plasma is controlled, and the film is formed at a uniform temperature.

  On the other hand, the cathode electrode 101 is disposed above the paired anode electrodes 102 and is made of a material such as stainless steel or aluminum alloy. The dimensions of the cathode electrode 101 may be designed to an appropriate value in accordance with the dimensions of the substrate, similarly to the anode electrode 102.

The cathode electrode 101 is connected to an external plasma excitation power source 106. As the plasma excitation power source 106, for example, an RF power source having an output power of 20 × 10 ⁻⁶ W / mm ^{2 to} 5000 × 10 ⁻⁶ W / mm ² in accordance with the dimensions of the substrate at RF 1 MHz to 60 MHz is used.

The cathode electrode 101 is connected to a gas supply system (not shown) that supplies a processing gas. As the processing gas, for example, monosilane (SiH ₄ ) gas or the like can be used. The processing gas introduced into the cathode electrode 101 from the gas supply system is supplied into the processing container 103 from the bottom surface of the cathode electrode 101 toward the substrate on the anode electrode 102.

  Each of the cathode electrode 101 and the anode electrode 102 is supported at both ends by support portions (not shown). Therefore, the cathode electrode 101 and the anode electrode 102 have a structure in which the surfaces facing each other and the opposite surface are exposed to the gas phase in the processing vessel 103.

  In the plasma CVD apparatus 100 configured as described above, for example, the following operation is performed.

  First, the substrate is carried into the processing container 103 and placed on the anode electrode 102. Next, the exhaust device is activated, exhaust is performed from the exhaust pipe, and the inside of the processing container 103 is decompressed. In addition, the heater is activated to hold the substrate at a desired temperature through the anode electrode 102.

  Next, the film forming process gas supplied from the gas supply system is filled into the plasma generation region 105, which is the gap between the cathode electrode 101 and the anode electrode 102, via the cathode electrode 101. Further, by the operation of the plasma excitation power source 106, high frequency power is applied between the cathode electrode 101 and the anode electrode 102, whereby an electric field is generated in the plasma generation region 105, and the processing gas is turned into plasma. A film forming process is performed on the substrate by the active species generated when the processing gas is turned into plasma.

  After the film formation process for a predetermined time is performed, the supply of the processing gas into the processing container 103 is stopped, the plasma excitation power source 106 is stopped, and the substrate is unloaded from the processing container 103.

  Through the series of steps described above, the film forming process of the substrate by the plasma CVD apparatus 100 is completed.

  In the above description, the cathode-anode electrode pair is described as being arranged horizontally in the processing vessel 103. However, the present invention is not limited to this, and as shown in FIG. The structure by which the pair is arrange | positioned vertically may be sufficient.

  2 shows the plasma CVD apparatus 100 including one cathode-anode electrode pair in the processing vessel 103, the present invention is not limited to this, and a plurality of cathode-anodes as shown in FIG. It may be configured as a plasma CVD apparatus 200 having a multi-electrode structure including electrode pairs.

  In the plasma CVD apparatus 200, as shown in FIG. 4, a plurality of sets of cathode-anode electrodes are arranged in the processing vessel 103 at substantially equal intervals. In FIG. 4, only the uppermost cathode electrode 101 is shown as a representative connection to the plasma excitation power source 106, but actually, all the cathode electrodes 101 in the processing vessel 103 are connected to the plasma excitation power source 106. Has been. The number of cathode-anode electrode pairs arranged in the processing vessel 103 is not particularly limited, and an arbitrary number of cathode-anode electrode pairs can be arranged.

  Further, the plasma CVD apparatus 200 is not limited to the configuration in which the cathode-anode electrode pair is placed horizontally as in the plasma CVD apparatus 100, and the cathode-anode electrode pair is arranged vertically as shown in FIG. It may be a configured.

(Configuration of cathode electrode 101)
The configuration of the cathode electrode 101 will be described in more detail with reference to FIGS. 1, 6, and 7A and 7B.

  As shown in FIG. 1, the cathode electrode 101 includes a shower plate 2 and a backing plate (support plate) 3 so as to have a buffer chamber 4 therein. FIG. 1 is a sectional view partially showing the cathode electrode 101.

  The backing plate 3 is connected to a gas supply system (not shown). Inside the backing plate 3, although not shown, a passage for introducing a processing gas from a connection part with the gas supply system to the buffer chamber 4 is provided. Since the processing gas spreads over the entire cathode electrode 101 in the buffer chamber 4, the processing gas can be uniformly supplied to the substrate through the buffer chamber 4.

  On the other hand, the shower plate 2 is disposed to face the lower side of the backing plate 3, and a plurality of intermediate fastening portions 6 and outer peripheral fastening portions 7 are formed on the surface facing the backing plate 3. The shower plate 2 is in contact with the backing plate 3 on the upper surfaces of the intermediate fastening portion 6 and the outer periphery fastening portion 7. A surface that contacts the backing plate 3 in the intermediate fastening portion 6 is referred to as a contact surface 8. The shower plate 2 is fastened to the backing plate 3 by screws 5. In the outer periphery fastening part 7, it is preferable that the fastening pitch by the screw 5 is equal.

  As shown in FIG. 6, the outer periphery fastening portion 7 is a rib formed so as to surround the outer periphery of the buffer chamber 4, and is formed integrally with the shower plate 2. FIG. 6 is an exploded perspective view partially showing the shower plate 2 as viewed from above. 1 is a cross-sectional view of the cathode electrode 101 taken along the line A-A ′ in FIG. 6.

  As shown in FIG. 6, the intermediate fastening portion 6 is a rib formed intermittently in the buffer chamber 4 and is formed integrally with the shower plate 2. The shape of the intermediate fastening portion 6 is not particularly limited, and examples thereof include prismatic shapes such as prisms and cylinders, and as shown in FIG. 6, the shape is chamfered so that the corners of the prisms are curved. Also good. Although the number of the intermediate | middle fastening parts 6 should just be one or more, it is preferable that two or more are formed like this embodiment.

  The cathode electrode 101 generally has a cross section as shown in FIGS. 7A is a cross-sectional view of the cathode electrode 101 taken along the line BB ′ in FIG. 6, and FIG. 7B is a cross-sectional view of the cathode electrode 101 taken along the line CC ′ in FIG. FIG.

  As shown in FIG. 7B, the buffer chamber 4 is connected so that the processing gas circulates in the cathode electrode 101 as a whole.

  7A and 7B, the shower plate 2 is formed with a plurality of holes 9 through which the buffer chamber 4 and the processing container 103 penetrate vertically. The processing gas supplied to the buffer chamber 4 is supplied into the processing container 103 through the holes 9.

  In addition, as shown to Fig.7 (a), it is preferable that the intermediate fastening part 6 and the hole 9 in the shower plate 2 are provided so that a mutual position may not overlap. That is, in the shower plate 2, the intermediate fastening portion 6 is preferably formed in a region between the holes 9. Accordingly, the plurality of holes 9 communicating with the buffer chamber 4 and the processing container 103 are not blocked, and the passage of the processing gas through the holes 9 can be avoided.

(Preventing warpage and distortion in the cathode electrode 101)
The intermediate fastening portion 6 not only functions as a fastening portion with the backing plate 3 but also plays a role of transferring the heat of the shower plate 2 to the backing plate 3. Specifically, when plasma is generated in the plasma CVD apparatus 100, the heat of the plasma is transmitted to the shower plate 2 as indicated by an arrow in FIG. At this time, the transmitted heat of the shower plate 2 is further transmitted to the backing plate 3 through the intermediate fastening portion 6. More specifically, the heat of the shower plate 2 is transmitted to the backing plate 3 via the contact surface 8 between the backing plate 3 and the intermediate fastening portion 6.

  For the heat transfer, a value obtained by dividing the ratio of the total area of the plurality of contact surfaces 8 to the area of the bottom surface of the buffer chamber 4 by the input power density to the cathode electrode 101 is preferably 5 or more. Here, the bottom surface of the buffer chamber 4 means a region that does not include the region where the intermediate fastening portion 6 is formed and faces the buffer chamber 4 on the surface of the shower plate 2 where the intermediate fastening portion 6 is formed. . If the area of the contact surface 8 is in the above range, the shower plate 2 can effectively transmit the heat amount from the plasma generated by power supply to the backing plate 3 via the intermediate fastening portion 6.

  Further, for the heat transfer, it is preferable that the upper surface of the intermediate fastening portion 6 is flat and is in close contact with the backing plate 3 over the entire surface. Furthermore, in order to further improve the heat conduction, a heat conduction sheet, grease, or the like may be put in a portion of the intermediate fastening portion 6 where the shower plate 2 and the backing plate 3 are in contact.

  According to the present embodiment, even if the cathode electrode 101 does not include a temperature control device such as a heater, the temperature difference between the shower plate 2 and the backing plate 3 is suppressed by heat conduction through the intermediate fastening portion 6 described above. can do. For this reason, even when plasma is generated, the cathode electrode 101 is maintained at a uniform temperature as a whole.

  Further, the intermediate fastening portion 6 exists as a rib in the surface of the shower plate 2 and improves the strength of the shower plate 2. Furthermore, since the outer periphery fastening portion 7 exists as a rib on the outer periphery of the shower plate 2, local distortion in the shower plate 2 is suppressed.

  Therefore, the cathode electrode 101 is prevented from warping and distortion, and this embodiment can provide the plasma CVD apparatus 100 that can stably perform the film forming process and the dry cleaning.

(Dimension of cathode electrode 101)
Next, the dimensions of the cathode electrode 101 in the present embodiment will be described with reference to FIGS. FIG. 8A is a cross-sectional view showing the intermediate fastening portion 6, and FIG. 8B is a cross-sectional view showing the outer periphery fastening portion 7.

  As shown in FIGS. 8A and 8B, the thickness t of the shower plate 2 is preferably 3 mm or more.

  For example, during the thin film processing of the plasma CVD apparatus 100, the thin film material adheres not only to the target substrate but also to the surface of the cathode electrode 101 (particularly the shower plate 2). When the number of depositions is increased, the thickness of the film attached to the cathode electrode 101 increases, and the internal stress of this film acts on the cathode electrode 101. Here, the conventional cathode electrode shower plate has a thickness of less than 3 mm, particularly for processing reasons. For this reason, the conventional shower plate does not have sufficient rigidity to cope with the internal stress of the attached film, and the cathode electrode is warped.

  On the other hand, in the present invention, since the thickness t of the shower plate 2 is 3 mm or more, the cathode electrode 101 is not only deformed due to the temperature difference but also deformed due to the internal stress of the film attached to the shower plate 2. Can also be prevented.

The height h ₂ of the buffer chamber 4 is preferably 10 to 60% with respect to the height h ₁ of the cathode electrode 101. Thereby, an increase in the total weight of the cathode electrode 101 accompanying the thickness of the shower plate 2 can be suppressed.

  Further, the hole 9 opened in the shower plate 2 has a diameter of about 1 mm. When the thickness of the shower plate 2 is 5 times or more the diameter (1 mm), the aspect ratio of the holes 9 is increased, and the processing becomes difficult. Therefore, in this embodiment, in order to process the hole 9 in the shower plate 2, first, a drill having a large diameter is used, and the remaining thickness of the shower plate 2 is about five times the diameter (1 mm) of the hole 9. Drill a hole. Next, the remaining processing is performed using a drill having a small diameter (1 mm), and thereby the hole 9 is opened. For this reason, the hole 9 has a convex shape as shown in FIGS.

  In addition, in embodiment mentioned above, although the intermediate | middle fastening part 6 and the outer periphery fastening part 7 are demonstrated as what is formed in the shower plate 2, this invention is not limited to this. For example, as shown in FIG. 9, the intermediate fastening portion 16 and the outer periphery fastening portion 17 may be formed on the backing plate 13. According to the configuration shown in FIG. 9, the temperature difference between the shower plate 12 and the backing plate 13 can be suppressed by heat conduction by the intermediate fastening portion 16. Therefore, similarly to the above-described embodiment, deformation of the cathode electrode 101 due to the temperature difference can be prevented.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims. In other words, embodiments obtained by appropriately combining technical means disclosed in different embodiments are also included in the technical scope of the present invention.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example, this invention is not limited to a following example.

  As Examples 1 and 2, the same plasma CVD apparatus as in the above-described embodiment was used. In Example 1, the ratio of the total area of the plurality of contact surfaces 8 to the area of the bottom surface of the buffer chamber 4 was 6.01%. In Example 2, the ratio was 1.20%. The number of cathode-anode electrode pairs arranged in the processing vessel 103 is four.

  As Comparative Examples 1 and 2, the same plasma CVD apparatus as in Examples 1 and 2 was used except for the configuration of the cathode electrode. Regarding the configuration of the cathode electrode, in Comparative Example 1, the shower plate and the backing plate were connected only by the outer periphery fastening portion 7. In Comparative Example 2, the ratio was set to 0.07%.

(Temperature difference at cathode electrode)
In Examples 1 and 2 and Comparative Examples 1 and 2, a simulation was performed to see how the temperature difference between the shower plate and the backing plate shows in a transient state of temperature rise. The simulation was performed for power condition 1: 900 × 10 ⁻⁶ W / mm ² input and power condition 2: 1300 × 10 ⁻⁶ W / mm ² input. The power condition 1 can be a power condition during normal thin film formation, and the power condition 2 can be a power condition during high-power dry cleaning.

  The comparison of the temperature difference was performed when 24 hours passed after the power was turned on.

  As a result, the results shown in Table 1 were obtained. The temperature difference means the difference between the maximum temperature in the shower plate and the minimum temperature in the backing plate.

As shown in Table 1, in Examples 1 and 2, it was found that the temperature difference can be suppressed as compared with Comparative Examples 1 and 2. In particular, when 1300 × 10 ⁻⁶ W / mm ^{2 of} power was turned on, the effect of Example 1 was noticeable.

According to the above results, it became clear that the temperature difference in the cathode electrode can be suppressed even during high power dry cleaning of 1300 × 10 ⁻⁶ W / mm ² .

(Curve amount of cathode electrode)
In Examples 1 and 2 and Comparative Examples 1 and 2, simulation of the amount of warpage of the cathode electrode due to temperature difference was performed.

  Specifically, a simulation was performed on the deformation amount of the cathode electrode in each example and each comparative example under the same conditions as the temperature difference simulation.

  As a result, the results shown in Table 1 were obtained. In Table 1, the amount of deformation means the amount of deformation in the direction of the opposing anode electrode, that is, the change in the gap between the cathodes.

  As shown in Table 1, in Examples 1 and 2, it was found that the amount of deformation can be suppressed compared to Comparative Examples 1 and 2. In particular, in Example 1, the amount of deformation could be more effectively suppressed.

  In addition, as shown in FIG. 10A, the above results are obtained by dividing the ratio of the total area of the plurality of contact surfaces 8 with respect to the area of the bottom surface of the buffer chamber 4 by the input power density, with the vertical axis as the deformation amount. As a result, the simulation results were plotted. From this result, it was found that when the above value is 5 or more, the amount of deformation can be particularly suppressed.

  Similarly, in FIG. 10B, it was found that the temperature difference can be particularly suppressed when the vertical axis is the temperature difference when the value is 5 or more.

  Further, in Examples 1 and 2, a constant film thickness (for example, 1 μm) was actually deposited, and the film thickness uniformity within the substrate surface was compared. The results are shown in FIG. In addition, about the measurement location of the film thickness in a board | substrate, as shown in FIG.

  As shown in FIG. 11, in Example 1, the film thickness uniformity in the substrate surface was improved as compared with Example 2, and good results were obtained. Therefore, it was found that according to Example 1 in which the deformation amount of the cathode electrode is smaller than that of Example 2, the film thickness can be deposited more uniformly.

  The present invention can be used as, for example, a plasma CVD apparatus for forming a thin film.

2 Shower plate 3 Backing plate 4 Buffer chamber 6 Intermediate fastening portion 7 Peripheral fastening portion 100, 200 Plasma CVD apparatus 101 Cathode electrode 102 Anode electrode 103 Processing vessel (processing chamber)
106 Plasma excitation power supply

Claims (7)

A plasma CVD apparatus for forming a film on a substrate by converting a processing gas into a plasma in a processing chamber,
It comprises an electrode pair that is exposed to the gas phase and is disposed opposite to each other in the processing chamber and that converts the processing gas into plasma,
At least one of the electrodes constitutes a buffer chamber for supplying the processing gas to the processing chamber by a support plate and a shower plate having a plurality of through-holes provided in the electrode,
The plasma CVD apparatus, wherein the support plate and the shower plate are connected by at least one intermediate fastening portion.   2. The plasma CVD apparatus according to claim 1, wherein a plurality of sets of the electrode pairs are arranged in the processing chamber.   The plasma CVD apparatus according to claim 1 or 2, wherein the electrode constituting the buffer chamber is a cathode electrode.   The rib-shaped outer periphery fastening part which contacted the said support plate is formed in the outer peripheral part of the surface facing the said support plate in the said shower plate, The any one of Claims 1-3 characterized by the above-mentioned. The plasma CVD apparatus as described.   The plasma CVD apparatus according to claim 1, wherein the intermediate fastening portion is formed integrally with the shower plate.   The plasma CVD apparatus according to any one of claims 1 to 5, wherein the intermediate fastening portion is formed in a region between the holes in the shower plate.   The ratio of the total area of the contact surface where the shower plate or the support plate contacts the plurality of intermediate fastening portions to the area of the bottom surface of the buffer chamber divided by the input power density for the electrode pair is 5 or more The plasma CVD apparatus according to claim 1, wherein:

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