Plasma processing apparatus and control method thereof

Abstract

To provide a plasma treatment apparatus capable of securing a uniform film thickness distribution for a treatment body even in a case where a shower plate is deformed.SOLUTION: A plasma treatment apparatus 1B according to the invention includes a gas introduction pipe 7 which connects an electrode flange 4 arranged in a chamber 2 to a gas supply part 21 via a flow meter 22. The electrode flange further includes a gas suction pipe 62 connected to pressure measurement means 60 for measuring a pressure in a space 24 formed between the electrode flange and a shower plate 5.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a plasma processing apparatus that supplies a film-forming gas through fine holes in a shower plate and that can obtain a uniform film thickness distribution on a workpiece when forming a film on the workpiece by plasma CVD. [Background technology]

[0002] Conventionally, plasma processing apparatuses have been known that introduce a film-forming gas into a film-forming space above a substrate through fine holes in a shower plate to generate plasma and form a desired film on the substrate (for example, see Patent Document 1). Plasma processing apparatuses with such a configuration are often used when forming various types of films on the surfaces of substrates such as silicon, glass, and ceramics by CVD or the like.

[0003] In such a plasma processing apparatus, a film formation process is repeatedly performed in which a film formation gas is introduced into a film formation space, plasma is generated, and a film is formed on a substrate. During this process, the shower plate may be thermally deformed. This deformation creates a gap between the outer periphery of the shower plate and the supporting portion, and the film formation gas flows into the film formation space through this gap.

[0004] As a result, in the central region of the shower plate, a normal flow rate of film formation gas is supplied to the film formation space through the fine holes, whereas near the outer periphery of the shower plate, a larger amount of film formation gas is supplied to the film formation space through the gaps described above than in the central region of the shower plate. As a result, the film formed on the substrate positioned opposite the underside of the shower plate has a large film thickness distribution. As will be described later, it was confirmed that thick films tend to be formed on the substrate positioned opposite the outer edge of the shower plate, while thin films tend to be formed on the substrate positioned opposite the central region of the shower plate (Figure 7). When this kind of problem (large film thickness distribution) occurs, it impairs the reproducibility of the film formation process, which is undesirable.

[0005] Therefore, there has been a demand for the development of a plasma processing apparatus that can obtain a uniform film thickness distribution on the object to be processed even when deformation occurs in the shower plate. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-328021 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in view of the above circumstances, and has as its object to provide a plasma processing apparatus that can obtain a uniform film thickness distribution on a processing object even when deformation occurs in the shower plate. [Means for solving the problem]

[0008] In order to solve the above problems, ( 1 ) The invention described in A plasma processing apparatus, a processing chamber having a film formation space (reaction chamber) and including a chamber, an electrode flange having a gas introduction pipe, and an insulating flange sandwiched between the chamber and the electrode flange; a support part accommodated in the film formation space, on which a substrate having a processing surface is placed, and having a function of controlling the temperature of the substrate; a film deposition chamber disposed in the film deposition space and facing the processing surface; In the space below a shower plate having a plurality of small holes for supplying a process gas toward the substrate; a voltage application unit that applies a voltage between the shower plate and the support unit to generate plasma of the process gas; Including, before The electrode flange is formed between the electrode flange and the shower plate. Upward The pressure measuring means further includes a gas suction tube that is connected to the pressure measuring means for measuring the pressure in the space.、 the gas introduction pipe is connected to a gas supply unit via a flow meter and is also connected to the upper space; the shower plate has an outer edge portion in surface contact with a peripheral edge portion of the electrode flange, is supported by the peripheral edge portion of the electrode flange, and is positioned parallel to the substrate; the shower plate is thermally deformed by the influence of a film formation process, and a second space communicating with the upper space and the lower space is formed between the shower plate and the peripheral edge of the electrode flange, which has been in surface contact with the outer edge of the shower plate to seal it, and when the process gas leaks into the lower space through the second space at the outer edge, the pressure measuring means detects a pressure decrease in the upper space, The flow meter has a function of controlling the amount of the process gas leaking into the lower space through the second space based on information from the pressure measuring means so as to increase the flow rate of the process gas supplied from the gas inlet pipe into the upper space, thereby maintaining the pressure in the upper space while a film formation process is being performed in the film formation space within a predetermined range when the process gas is not leaking through the second space. Ta, It is characterized by:

[0009] (2) The invention described in (1) In The aforementioned Upward The apparatus is characterized by having a function of stopping the film formation process on the processing surface of the substrate when the pressure in the space falls outside a predetermined range.

[0010] (3) The invention described in a processing chamber having a film formation space (reaction chamber) and including a chamber, an electrode flange having a gas introduction pipe, and an insulating flange sandwiched between the chamber and the electrode flange; a support part accommodated in the film formation space, on which a substrate having a processing surface is placed, and having a function of controlling the temperature of the substrate; a shower plate accommodated in the film formation space, disposed opposite the processing surface, and having a plurality of small holes for supplying a process gas toward the substrate in the space below; a voltage application unit that applies a voltage between the shower plate and the support unit to generate plasma of the process gas; Including, the electrode flange further includes a gas suction pipe connected to a pressure measuring means for measuring a pressure in an upper space formed between the electrode flange and the shower plate, the gas introduction pipe is connected to a gas supply unit via a flow meter and is also connected to the upper space; a control method for a plasma processing apparatus, the shower plate being supported by a peripheral edge portion of the electrode flange with an outer edge portion in surface contact with the peripheral edge portion of the electrode flange, and being positioned parallel to the substrate, the method comprising: the shower plate is thermally deformed by the influence of a film formation process, and a second space communicating with the upper space and the lower space is formed between the shower plate and the peripheral edge of the electrode flange, which has been in surface contact with the outer edge of the shower plate to seal it, and when the process gas leaks into the lower space through the second space at the outer edge, the pressure measuring means detects a pressure decrease in the upper space, The flow meter controls the amount of the process gas leaking into the lower space through the second space based on information from the pressure measuring means so as to increase the flow rate of the process gas supplied from the gas inlet pipe into the upper space, thereby maintaining the pressure in the upper space during a film formation process in the film formation space within a predetermined range when the process gas is not leaking through the second space. , It is characterized by: [Effects of the Invention]

[0011] In the invention (plasma processing apparatus) of claim 1, an electrode flange disposed in a chamber includes a gas inlet pipe connected to a gas supply unit via a flow meter. The electrode flange further includes a gas suction pipe connected to a pressure measurement means for measuring the pressure in the space formed between the electrode flange and the shower plate. This allows the pressure measurement means to grasp the pressure P1 in the space while a film formation process is being performed in the film formation space. Based on information about this pressure P1, the flow meter controls the flow rate of film formation gas introduced from the gas inlet pipe connected to the gas supply unit. This allows the pressure P1 in the space to be managed so that conditions are met for obtaining a desired film thickness distribution and film formation rate for a film formed on a substrate. Therefore, the present invention contributes to providing a plasma processing apparatus that can obtain a uniform film thickness distribution and a desired film formation rate on a processing object even when the shower plate is deformed. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic cross-sectional view showing the configuration of a plasma processing apparatus according to the present invention. [Figure 2] FIG. 1 is a schematic cross-sectional view showing the configuration of a conventional plasma processing apparatus. [Figure 3] 3 is a schematic plan view of the plasma processing apparatus of FIG. 2 at the position of the upper surface of the shower plate. [Figure 4] Schematic cross-sectional views showing an enlarged view of the area surrounded by the dashed line in Figure 2. (A) is the shower plate before deformation, and (B) is the shower plate after deformation. [Figure 5] 10 is a graph showing a film thickness distribution before deformation of the shower plate. [Figure 6] 10 is a graph showing a film thickness distribution after deformation of the shower plate. [Figure 7] 10 is a graph showing a film thickness distribution according to the degree of deformation of the shower plate. [Figure 8] 10 is a graph showing the relationship between the film formation rate (DR) and the amount of gas leakage versus the pressure (P1) in the space. DETAILED DESCRIPTION OF THE INVENTION

[0013] In the following, in order to clarify the problem of the present invention, a conventional plasma processing apparatus and its problems will be described with reference to Figures 2, 3, 4(A) and 4(B). Note that in each drawing used in the following description, the scale of each component has been appropriately changed so that each component can be recognized.

[0014] (Conventional plasma processing device) Fig. 2 is a schematic cross-sectional view showing the configuration of a conventional plasma processing apparatus, and Fig. 3 is a schematic plan view of the plasma processing apparatus of Fig. 2 seen from above at the position of the upper surface of the shower plate. Fig. 4(A) and Fig. 4(B) are both graphs showing film thickness distribution, Fig. 4(A) shows the case before the shower plate is deformed, and Fig. 4(B) shows the case after the shower plate is deformed. As an example of the plasma processing apparatus, a film forming apparatus (plasma processing apparatus) 1B for carrying out the plasma CVD method will be described in detail below based on its configuration.

[0015] As shown in FIG. 2, a film formation apparatus 1B for performing plasma CVD has a vacuum chamber (chamber) 2 configured as a film formation chamber. The vacuum chamber 2 is grounded. A support 25 is disposed at the bottom of the vacuum chamber 2 so as to pass through the bottom 11 of the vacuum chamber 2, and the tip of the support 25 (inside the vacuum chamber 2) is connected to the back surface 17 of the plate-shaped support member 15. An electrode flange 4 is attached to the top of the vacuum chamber 2 via an insulating flange 81. An exhaust pipe 27 is connected to the bottom 11 of the vacuum chamber 2, and a vacuum exhaust system 28 consisting of a vacuum pump is provided at the tip of the exhaust pipe 27, so that the inside of the vacuum chamber 2 can be evacuated or evacuated.

[0016] Furthermore, the support pillars 25 are connected to a lifting mechanism (not shown) provided outside the vacuum chamber 2, and are configured to be movable in the vertical direction. In other words, the support parts 15 on which the substrate 10 is placed, which are connected to the tips of the support pillars 25, are configured to be able to be raised and lowered in the vertical direction. This configuration makes it easy to put in and take out the substrate 10. Furthermore, outside the vacuum chamber 2, bellows (not shown) are provided to cover the periphery of the support pillars 25.

[0017] The support 15 is a plate-like member having a flat surface and a rectangular shape in plan view, and a heating means (not shown) consisting of a heater is embedded on the upper surface side of the support 15. The support 15 is made of a nickel-based alloy such as Inconel (registered trademark). The support 15 may be made of any material as long as it is rigid and has corrosion resistance and heat resistance. The support 15 and the vacuum chamber 2 are connected by an earth plate 30, and the support 15 and the heating means (not shown) are configured to function as a ground electrode (anode electrode) 72.

[0018] The heating means (not shown) is a plate-like member that is rectangular in plan view and has a flat surface, similar to the support portion 15, and the substrate 10 is placed on its upper surface. The heating means (not shown) is made of, for example, an aluminum alloy. The heating means (not shown) functions as a ground electrode, so a conductive material is used. When the substrate 10 is placed on the support portion 15, the substrate 10 and the shower plate 5 (described later) are configured to be positioned close to each other and "parallel." With the substrate 10 placed on the heating means (not shown), film formation gas is ejected from gas ejection ports 6 formed in the shower plate 5, and the film formation gas is sprayed onto the surface 10a of the substrate 10.

[0019] The heating means (not shown) contains a heater wire 16 therein and is configured to be temperature adjustable. The heater wire 16 protrudes from a rear surface 17 of the support portion 15 at approximately the center in a plan view, passes through a through-hole 18 formed at approximately the center of the support portion 15 in a plan view, and passes through the inside of a support column 25, and is led to the outside of the vacuum chamber 2. The heater wire 16 is connected to a power source (not shown) outside the vacuum chamber 2, and is configured to be temperature adjustable. The support portion 15 with this built-in heating means (not shown) is configured to hold a substrate.

[0020] The electrode flange 4 is formed in a lid shape so as to close the vacuum chamber 2, and is disposed so that its peripheral edge abuts against the insulating flange 81 with the cathode electrode 71 sandwiched therebetween. In addition, a shower plate 5 is provided on the side of the electrode flange 4 facing the inside of the vacuum chamber 2, with a predetermined distance therebetween. Therefore, a space 24 is formed between the shower plate 5 and the electrode flange 4.

[0021] A gas inlet pipe 7 is connected to the electrode flange 4, and is configured to supply a raw material gas (e.g., SiH4) to a space 24 from a process gas (film forming gas) supply unit (shown as "process gas" in FIG. 2) 21 provided outside the vacuum chamber 2. The flow rate of the film forming gas released into the space from the gas inlet 7a of the gas inlet pipe 7 can be adjusted by a flow meter 22. Thus, the process gas control unit 20 is composed of the process gas supply unit (gas supply unit) 21 and the flow meter 22. Furthermore, a carrier gas made of argon gas or nitrogen gas may be supplied together with the film forming gas. This carrier gas is also supplied from the process gas supply unit 21 to the space 24.

[0022] Furthermore, the shower plate 5 is provided with a large number of gas outlets (also called fine holes) 6, and is configured so that the film formation gas introduced into the space 24 is ejected approximately evenly through the gas outlets 6 into the film formation space 2a of the vacuum chamber 2. In other words, the process gas introduced into the space 24 from the process gas supply unit 21 through the gas inlet pipe 7 and the gas inlet port 7a reaches the upper surface 5a of the shower plate 5, and then is ejected into the film formation space 2a of the vacuum chamber 2 through the gas ejection ports (micropores) 6 formed in the shower plate 5.

[0023] FIG. 3 is a schematic plan view of the plasma processing apparatus of FIG. 2 seen from above at the position of the upper surface 5a of the shower plate 5. As shown in FIG. 3, reference numeral 2 denotes a vacuum chamber, reference numeral 81 denotes an insulating flange, and reference numeral 71 denotes a cathode electrode. It was found that the side surface 5e of the outer edge portion 5b of the shower plate 5 is normally located at the position of side surface 5eI (solid line), but deforms to the position of side surface 5eH (two-dot chain line) when heated.

[0024] Fig. 4 is a schematic cross-sectional view showing an enlarged view of the area surrounded by the dashed line in Fig. 2, where Fig. 4(A) shows the shower plate before deformation and Fig. 4(B) shows the shower plate after deformation. That is, Fig. 4 corresponds to a cross-sectional view taken along line IVA-IVA in Fig. 3.

[0025] As shown in Fig. 4(A), the outer edge 5b of the shower plate 5 before deformation is sandwiched and supported between the lower end 71a and upper end 71b of the cathode electrode 71, and the outer edge 5b of the shower plate 5 and the lower end 71a of the cathode electrode 71, and the outer edge 5b and the upper end 71b are in surface contact with each other. In Fig. 4(A), symbol 5aI indicates the upper surface of the shower plate 5 before deformation. Symbol 5LI indicates that the upper surface 5aI of the shower plate 5 is maintained flat from the outer edge 5b of the shower plate 5 toward the central region [right side in Fig. 4(A)].

[0026] However, as shown in Figure 4(B), the shower plate 5 is thermally deformed due to the influence of the film formation process. As shown in Figure 3, the side surface 5e of the outer edge 5b of the shower plate 5 is deformed up to the position of the side surface 5eH (indicated by the two-dot chain line in Figure 3) when heated. Furthermore, the material strength decreases due to heating, and the shower plate can no longer support its own weight and sags. As a result, the upper surface 5aH of the shower plate 5 from the outer edge 5b of the shower plate 5 to the central region [right side in Figure 4(B)] loses flatness and deforms into a downward convex shape. The symbol 5LH represents this deformed state.

[0027] 4(A), the separated portion 71s becomes a space (hereinafter also referred to as a second space) that communicates between the space above the shower plate (the space to which the process gas is supplied) and the space below the shower plate (the film formation space) when the deformation shown in FIG. 4(B) occurs in the shower plate. In other words, a phenomenon occurs in which a large amount of the process gas that was originally supplied to the film formation space through the fine holes leaks into the film formation space through the second space.

[0028] FIG. 5 is a graph showing the film thickness distribution before the shower plate is deformed, and FIG. 6 is a graph showing the film thickness distribution after the shower plate is deformed. Although the deposition conditions in Figures 5 and 6 were the same, the film thickness distribution in Figure 5 was good (Uni.: ±2.9%), whereas the film thickness distribution in Figure 6 was more than three times worse (Uni.: ±11.1%). As a result, the deposition rate (DR) also decreased [from 257.5 nm / min in Figure 5 to 193.0 nm / min in Figure 6]. 5 and 6, it was found that when the process gas leaks into the film formation space through the second space, the film thickness distribution deteriorates and the film formation rate decreases.

[0029] 7 is a graph showing the film thickness distribution according to the degree of deformation of the shower plate. The black diamonds represent the results before the shower plate was deformed. The cross marks, triangle marks, and open square marks all represent the results after the shower plate was deformed. The cross marks represent results at 320°C, the triangle marks at 350°C, and the open square marks at 400°C. This means that the temperature causes the thermal deformation to progress, increasing the amount of process gas flowing into the film formation space through the second space. From the results of the cross marks, triangle marks, and open square marks, it was confirmed that after the shower plate deformation, the film thickness distribution deteriorated and the film formation rate decreased due to the effect of the process gas leaking into the film formation space through the second space.

[0030] The present inventors investigated the relationship between the pressure (P1) in the second space and the deposition rate (DR) in relation to the phenomenon of the process gas leaking into the deposition space through the second space. Figure 8 is a graph showing the results. Figure 8 makes the following two points clear. (a1) When the pressure (P1) is changed from low to high, the deposition rate (DR) tends to increase monotonically. (a2) When the pressure (P1) is changed from low to high, the amount of gas leakage tends to decrease monotonically. Furthermore, when the amount of process gas is increased and the pressure (P1) is increased while the process gas is leaking into the film formation space through the second space, the film formation rate and film thickness distribution are found to reproduce the values ​​when the process gas is not leaking into the film formation space. In other words, if the electrode flange 4 can supply the amount of process gas leaking into the film formation space through the second space into the space formed between the electrode flange 4 and the shower plate 5, the problem of film thickness distribution caused by the phenomenon of process gas leaking into the film formation space through the second space can be resolved.

[0031] In order to utilize the results found from FIG. 8, it is necessary to know the pressure (P1) when the film formation process is being carried out in the film formation space (that is, during film formation). FIG. 1 is a schematic cross-sectional view showing the configuration of a plasma processing apparatus according to the present invention. 1 differs from the plasma processing apparatus 1B shown in Fig. 2 only in that the electrode flange 4 further includes a gas suction pipe 62 that leads to a pressure measurement means 60 that measures the pressure P1 in the space formed between the electrode flange and the shower plate 5. The pressure measurement means 60 is composed of a pressure gauge 61 and a gas suction pipe 62. Reference numeral 62a denotes a gas suction port of the gas suction pipe 62.

[0032] In the plasma processing apparatus 1A of FIG. 1, the electrode flange 4 disposed in the chamber is provided with a gas inlet pipe 7 connected to a process gas supply unit 21 via a flow meter 22, and the electrode flange 4 is provided with a gas suction pipe 62 leading to a pressure gauge 61 that measures a pressure P1 in a space formed between the electrode flange and the shower plate 5. As a result, the pressure gauge 61 that measures the pressure P1 can grasp the pressure P1 in the film formation space 2a while the film formation process is being carried out in the space. Based on the information on the pressure P1, the flow meter 22 can control the flow rate of the film forming gas introduced from the gas introduction pipe 7 connected to the gas supply unit 21. This makes it possible to control the pressure P1 in the space so that the conditions for obtaining a desired film thickness distribution for the film formed on the surface 10a of the substrate 10 are met. Therefore, according to the present invention, even if the shower plate 5 is deformed, a plasma processing apparatus can be obtained that can realize a film formation process that obtains a uniform film thickness distribution on the substrate (object to be processed) 10.

[0033] Furthermore, it is preferable that the flow meter 22 has a function of controlling the flow rate of the gas supplied from the gas inlet pipe into the space based on information from a pressure measuring means that measures the pressure, thereby maintaining the pressure in the space within a predetermined range while a film formation process is being performed in the film formation space, thereby automating the task of maintaining the pressure P1 in the space within the predetermined range.

[0034] Furthermore, it is preferable that the flow meter 22 has a function of halting the film deposition process on the processing surface of the substrate when the pressure in the space falls outside a predetermined range, thereby making it possible to avoid a situation in which the film deposition process is continued under conditions that result in a poor film thickness distribution, resulting in the production of defective products.

[0035] The technical scope of the present invention is not limited to the above-described embodiments, but includes various modifications to the above-described embodiments without departing from the spirit of the present invention. In other words, the specific materials and configurations given in the embodiments are merely examples and can be modified as appropriate. [Industrial Applicability]

[0036] The present invention can be widely applied as a plasma processing apparatus that supplies film-forming gas through the fine holes in a shower plate and obtains a uniform film thickness distribution on a workpiece when forming a film on the workpiece by plasma CVD. Furthermore, the present invention is useful for a plasma processing apparatus that can suppress increases in manufacturing costs, easily and efficiently form a uniform film on a substrate, and ensure sufficient electrode strength when processing a substrate using a high-pressure depletion method with a narrow gap. [Explanation of symbols]

[0037] 1A...Plasma processing equipment (film forming equipment) 2...Vacuum chamber (chamber) 2a... Film formation space 4...Electrode flange 5...Shower plate 5a, 5aH, 5aI…Top surface 5b...Outer edge 5e,5eH,5eI…side 6...Gas outlet (microhole) 7...Gas introduction pipe 7a...Gas inlet 10...Substrate (object to be processed) 16...Heater wire 18...Through hole 20...Process gas control unit 21...Process gas supply unit (gas supply unit) 22…Flow meter 24…Space 25...post 27...Exhaust pipe 28...Vacuum exhaust system 30...Earth plate 60...Pressure measurement means 61...Pressure gauge 62...Gas suction tube 71...Cathode electrode 72...Ground electrode (anode electrode) 81...Insulating flange

Claims

1. A plasma processing apparatus, a processing chamber having a film formation space, the processing chamber comprising a chamber, an electrode flange having a gas introduction pipe, and an insulating flange sandwiched between the chamber and the electrode flange; a support part accommodated in the film formation space, on which a substrate having a processing surface is placed, the support part having a function of controlling the temperature of the substrate; a shower plate accommodated in the film formation space, disposed opposite the processing surface, and having a plurality of small holes for supplying a process gas toward the substrate in the space below; a voltage application unit that applies a voltage between the shower plate and the support unit to generate plasma of the process gas; Including, the electrode flange further includes a gas suction pipe connected to a pressure measuring means for measuring a pressure in an upper space formed between the electrode flange and the shower plate, the gas introduction pipe is connected to a gas supply unit via a flow meter and is also connected to the upper space; the shower plate has an outer edge portion in surface contact with a peripheral edge portion of the electrode flange, is supported by the peripheral edge portion of the electrode flange, and is positioned parallel to the substrate; the shower plate is thermally deformed by the influence of a film formation process, and a second space communicating with the upper space and the lower space is formed between the shower plate and the peripheral edge of the electrode flange, which has been in surface contact with the outer edge of the shower plate to seal it, and when the process gas leaks into the lower space through the second space at the outer edge, the pressure measuring means detects a pressure decrease in the upper space, the flow meter has a function of controlling the amount of the process gas leaking into the lower space through the second space based on information from the pressure measuring means so as to increase the flow rate of the process gas supplied from the gas inlet pipe into the upper space, thereby maintaining the pressure in the upper space during the film formation process in the film formation space within a predetermined range when the process gas is not leaking through the second space. A plasma processing apparatus characterized by:

2. a function of stopping a film formation process on the processing surface of the substrate when the pressure in the upper space falls outside a predetermined range; 2. The plasma processing apparatus according to claim 1, wherein the plasma processing apparatus is a plasma processing apparatus.

3. a processing chamber having a film formation space, the processing chamber comprising a chamber, an electrode flange having a gas introduction pipe, and an insulating flange sandwiched between the chamber and the electrode flange; a support part accommodated in the film formation space, on which a substrate having a processing surface is placed, the support part having a function of controlling the temperature of the substrate; a shower plate accommodated in the film formation space, disposed opposite the processing surface, and having a plurality of small holes for supplying a process gas toward the substrate in the space below; a voltage application unit that applies a voltage between the shower plate and the support unit to generate plasma of the process gas; Including, the electrode flange further includes a gas suction pipe connected to a pressure measuring means for measuring a pressure in an upper space formed between the electrode flange and the shower plate, the gas introduction pipe is connected to a gas supply unit via a flow meter and is also connected to the upper space; a control method for a plasma processing apparatus, the shower plate being supported by a peripheral edge portion of the electrode flange with an outer edge portion in surface contact with the peripheral edge portion of the electrode flange, and being positioned parallel to the substrate, the method comprising: the shower plate is thermally deformed by the influence of a film formation process, and a second space communicating with the upper space and the lower space is formed between the shower plate and the peripheral edge of the electrode flange, which has been in surface contact with the outer edge of the shower plate to seal it, and when the process gas leaks into the lower space through the second space at the outer edge, the pressure measuring means detects a pressure decrease in the upper space, the flow meter controls the amount of the process gas leaking into the lower space through the second space based on information from the pressure measuring means so as to increase the flow rate of the process gas supplied from the gas inlet pipe into the upper space, thereby maintaining the pressure in the upper space during the film formation process in the film formation space within a predetermined range when the process gas is not leaking through the second space.

2. A method for controlling a plasma processing apparatus comprising:

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