JP7709926B2 - SUBSTRATE PROCESSING APPARATUS AND SUBSTRATE PROCESSING METHOD - Google Patents

Description

This disclosure relates to a substrate processing apparatus and a substrate processing method.

In Patent Document 1, a workpiece having a silicon oxide film formed on its surface is placed on a mounting table in a chamber, and reactive gases HF gas and NH3 gas are discharged onto the workpiece on the mounting table from a plurality of gas discharge holes of a shower plate provided above the mounting table so as to correspond to the _workpiece placed on the mounting table. Then, a process is performed in which these gases react with the silicon oxide film on the surface of the workpiece, and then etching is performed by heating the reaction product generated by this reaction to decompose and remove it. The shower head in Patent Document 1 has a shower plate, and is structured to discharge HF gas from a plurality of first gas discharge holes provided in the shower plate and discharge _NH3 gas from a plurality of second discharge holes provided in the shower plate.

International Publication No. 2013-183437

When using a showerhead in which gas diffusion chambers for each gas type are stacked, the technology disclosed herein prevents one of two types of gases supplied separately from the showerhead to a processing space from flowing back into the gas diffusion chamber for the other gas inside the showerhead and being mixed.

One aspect of the present disclosure is a substrate processing apparatus that processes a substrate with a first gas and a second gas, comprising:
The present invention relates to a processing apparatus for processing a substrate, the method for manufacturing the processing apparatus, and a processing vessel having a processing space therein where the processing is performed on the substrate, a shower head that supplies the first gas and the second gas independently to the processing space, and a control unit. The shower head has a first gas diffusion chamber that diffuses the first gas, and a second gas diffusion chamber that is disposed below the first gas diffusion chamber and diffuses the second gas. The shower head has a first opening on a lower surface thereof for ejecting the first gas and a second opening on a lower surface thereof for ejecting the second gas. the control unit controls a pressure difference between the first gas diffusion chamber and the processing space to be 47 Pa or more and a gas flow rate per each of the plurality of first gas supply paths to be 0.15 sccm or more, and a narrow passage is provided in at least a portion of each of the first gas supply paths, and an aspect ratio of the length to the width of the narrow passage is 10 or more.

According to the present disclosure, when a showerhead in which gas diffusion chambers for each gas type are stacked is used, it is possible to prevent one of two types of gases independently supplied from the showerhead to a processing space from flowing back into the gas diffusion chamber for the other gas in the showerhead and being mixed therewith.

1 is a vertical cross-sectional view showing an outline of the configuration of a plasma processing apparatus as a substrate processing apparatus according to an embodiment of the present invention. FIG. 4 is a vertical cross-sectional view showing an outline of the configuration of a partial window. FIG. 2 is a bottom view of the first plate. FIG. 4 is a bottom view of the second plate. FIG. 13 is a bottom view of the third plate. FIG. 13 is a diagram for explaining the dimensions of a narrow passage of a first gas supply path. FIG. 13 is a diagram showing a simulation result. FIG. 13 is a diagram showing a simulation result. FIG. 13 is a diagram showing a simulation result.

In the manufacturing process of flat panel displays (FPDs) such as liquid crystal displays (LCDs), substrates such as glass substrates are subjected to processes such as etching and film formation using substrate processing equipment.

The substrate processing apparatus includes a processing vessel in which a substrate to be processed is accommodated, and a showerhead that supplies a processing gas to a processing space in the processing vessel.
In processes that require multiple types of gases, a post-mix system is often used in which multiple types of gases are supplied separately from the showerhead and mixed in the process chamber, rather than being mixed in the showerhead. The post-mix system is used, for example, when the gases used in the process are a flammable gas and a combustion-supporting gas, and mixing them in the showerhead could cause an explosion or the like.

In addition, in the post-mix method, a showerhead may be used that has a multi-stage structure in which one gas diffusion chamber that diffuses one gas horizontally and another gas diffusion chamber that diffuses another gas horizontally are stacked vertically. In this showerhead, one nozzle that sprays one gas in one gas diffusion chamber into the processing space and another nozzle that sprays another gas in the other gas diffusion chamber into the processing space are individually provided on the underside of the showerhead.

However, when using a multi-stage showerhead, one gas ejected from one gas outlet into the processing space may flow back through the gas outlet for the other gas and be mixed with the other gas inside the showerhead.

The technology disclosed herein prevents one of two types of gases supplied independently from the showerhead to the processing space from flowing back into the gas diffusion chamber for the other gas in the showerhead and being mixed when a showerhead is used in which gas diffusion chambers for each gas type are stacked.

The substrate processing apparatus and substrate processing method according to this embodiment will be described below with reference to the drawings. Note that in this specification and the drawings, elements having substantially the same functional configurations are designated by the same reference numerals, and duplicated descriptions will be omitted.

<Plasma Processing Apparatus 1>
FIG. 1 is a vertical cross-sectional view showing an outline of the configuration of a plasma processing apparatus as a substrate processing apparatus according to this embodiment.

The plasma processing apparatus 1 in FIG. 1 processes a rectangular glass substrate G (hereinafter referred to as "substrate G") as a substrate using two types of processing gases. More specifically, the plasma processing apparatus 1 processes the substrate G by plasma processing using plasma of two types of processing gases. In this embodiment, the plasma processing performed by the plasma processing apparatus 1 is a film formation process for FPDs. However, the plasma processing performed by the plasma processing apparatus 1 may also be an etching process, an ashing process, etc. for FPDs. The plasma processing performed by the plasma processing apparatus 1 forms electronic devices such as light-emitting elements and driving circuits for the light-emitting elements on the substrate G.

The plasma processing apparatus 1 includes a rectangular cylindrical container body 10. The container body 10 is made of a conductive material, such as aluminum, and is electrically grounded. When a corrosive gas is used in the plasma processing, the inner wall surface of the container body 10 is subjected to a corrosion-resistant coating treatment such as anodizing treatment in order to improve corrosion resistance. An opening is formed on the upper surface of the container body 10. This opening is airtightly sealed by a rectangular metal window 20 insulated from the container body 10, specifically, by the metal window 20 and a metal frame 14 described later. The space surrounded by the container body 10 and the metal window 20 becomes a processing space S1 in which processing (specifically, plasma processing) is performed on the substrate G, and the space above the metal window 20 becomes an antenna chamber S2 in which a high-frequency antenna (inductively coupled antenna) 80 described later is arranged. A loading/unloading port 11 for loading/unloading the substrate G into/out of the processing space S1 and a gate valve 12 for opening/closing the loading/unloading port 11 are provided on the side wall of the container body 10.

A substrate support 30 that supports a substrate G is provided at the lower side of the processing space S1 so as to face the metal window 20. The substrate support 30 has a main body 31 on which the substrate G is placed, and the main body 31 is installed on the bottom surface of the container body 10 via legs 32.

The main body 31 is made of a conductive material, such as aluminum. The surface of the main body 31 is subjected to a coating process such as anodizing or ceramic spraying to improve the surface emissivity.

If necessary, a high-frequency bias power supply may be connected to the main body 31.

An exhaust port 13 is formed on the bottom surface of the container body 10, and an exhaust unit 50 having a vacuum pump or the like is connected to this exhaust port 13. The processing space S1 is depressurized by this exhaust unit 50. The exhaust unit 50 may be provided for each of the multiple exhaust ports 13, or may be provided in common to the multiple exhaust ports 13.

A metal frame 14, which is a rectangular frame made of a metal material such as aluminum, is provided on the upper surface of the side wall of the container body 10. A seal member (not shown) is provided between the container body 10 and the metal frame 14 to keep the processing space S1 airtight. The container body 10, the metal frame 14, and the metal window 20 together form a processing container having the processing space S1 inside.

The metal window 20 is divided into a number of partial windows 21, which are arranged inside the metal frame 14 to form a rectangular metal window 20 as a whole. The partial windows 21 do not all have the same shape when viewed from above, and some have a square shape (e.g., a trapezoid) when viewed from above, and some have a triangular shape when viewed from above.

Each of the partial windows 21 is a shower head configured to be able to simultaneously supply a first processing gas and a second processing gas independently to the processing space S1. The first processing gas is, for example, a combustible gas, and in this embodiment, is _SiH4 gas. The second processing gas is, for example, a combustion supporting gas (specifically, an oxidizing gas), and in this embodiment, is _O2 gas.

The partial window 21 adjacent to the metal frame 14 is electrically insulated from the metal frame 14 by an insulating member 22 , and adjacent partial windows 21 are also electrically insulated from each other by the insulating member 22 .
In order to protect the insulating member 22, an insulating member cover 23 is provided on the insulating member 22 to cover the surface of the insulating member 22 facing the processing space S1.
Each partial window 21 is suspended and held from the ceiling surface side of the antenna room S2 via a holding portion (not shown).
The structure of the partial window 21 will be described in detail later.

Furthermore, each partial window 21 is connected to a first gas source 61 via a first supply pipe 60. Specifically, the inlet 131 (see FIG. 2 described later) of each partial window 21 is connected to the first gas source 61 via the first supply pipe 60. A first supply mechanism 62 is interposed in the first supply pipe 60. The first supply mechanism 62 includes an opening/closing valve 62a and a flow rate adjustment valve 62b, and supplies the first process gas from the first gas source 61 to the partial window 21 by adjusting the flow rate.

Each partial window 21 is connected to a second gas source 64 via a second supply pipe 63. Specifically, the inlet 132 (see FIG. 2 described later) of each partial window 21 is connected to the second gas source 64 via the second supply pipe 63. A second supply mechanism 65 is provided in the second supply pipe 63. The second supply mechanism 65 includes an opening/closing valve 65a and a flow rate adjustment valve 65b, and adjusts the flow rate of the second process gas from the second gas source 64 and supplies it to the partial window 21.

For ease of illustration, the figure shows the first supply pipe 60 and the second supply pipe 63 connected to only one partial window 21, but in reality, the first supply pipe 60 and the second supply pipe 63 are connected to each partial window 21.

Furthermore, a top plate portion 70 is disposed above the metal window 20. The top plate portion 70 is supported by a side wall portion 71 provided on the metal frame 14.

The space surrounded by the metal window 20, the side wall portion 71, and the top plate portion 70 constitutes the antenna chamber S2, and a high-frequency antenna 80 is disposed inside the antenna chamber S2 so as to face the partial window 21.

The high-frequency antenna 80 is disposed at a distance from the partial window 21 via a spacer (not shown) made of, for example, an insulating material. The high-frequency antenna 80 is formed concentrically, for example in a spiral shape, along the surface corresponding to each partial window 21 and going around the circumferential direction of the rectangular metal window 20, forming a multi-ring antenna.

A high frequency power supply 41 is connected to each high frequency antenna 80 via a matching box 40 as a plasma generating means. High frequency power of, for example, 13.56 MHz is supplied to each high frequency antenna 80 from the high frequency power supply 41 via the matching box 40. As a result, during plasma processing, eddy currents are induced that circulate from the upper surface to the lower surface of each partial window 21, and an induced electric field is formed inside the processing space S1 by the current that flows on the lower surface among these eddy currents. The processing gas supplied from the partial window 21 is turned into plasma inside the processing space S1 by the induced electric field.

The plasma processing apparatus 1 is further provided with a pressure gauge 90 for measuring the pressure in the processing space S1.

The plasma processing apparatus 1 is also provided with a control unit U. The control unit U is, for example, a computer equipped with a processor such as a CPU, a memory, etc., and has a program storage unit (not shown). The program storage unit stores a program for controlling the processing of the substrate G in the plasma processing apparatus 1. The above-mentioned program may be recorded on a computer-readable storage medium and installed from the storage medium into the control unit U. A part or all of the program may be realized by dedicated hardware (circuit board).

<Partial window 21>
Fig. 2 is a vertical cross-sectional view showing the outline of the configuration of the partial window 21. Figs. 3 to 5 are bottom views of first to third plates, respectively, which will be described later.
As shown in FIG. 2, each partial window 21 has a first gas diffusion space 101 and a second gas diffusion space 102 therein, and has a plurality of first openings 111 and a plurality of second openings 112 at its lower end.

The first gas diffusion chamber 101 diffuses a first processing gas ( _SiH4 gas in this embodiment) in the horizontal direction. The second gas diffusion chamber 102 is disposed below the first gas diffusion chamber 101 and diffuses a second processing gas ( _O2 gas in this embodiment) in the horizontal direction. Each of the first openings 111 ejects the first processing gas in the first gas diffusion chamber 101 into the processing space S1. Each of the second openings 112 ejects the second processing gas in the second gas diffusion chamber 102 into the processing space S1.

Each partial window 21 further has a plurality of first gas supply paths 121 and a plurality of second gas supply paths 122.

The plurality of first gas supply paths 121 communicate between the first gas diffusion chamber 101 and the plurality of first openings 111. That is, each of the first gas supply paths 121 communicates between the corresponding first openings 111 and the first gas diffusion chamber 101. Each of the first gas supply paths 121 passes through the second gas diffusion chamber 102. During this passage, the first gas supply path 121 and the second gas diffusion chamber 102 are separated from each other by, for example, a pipe wall of an induction pipe 222 described later so that the second process gas in the second gas diffusion chamber 102 is not mixed into the first gas supply path 121.
Further, a narrow passage 121 a (i.e., a portion narrower than other portions of the first gas supply passage 121 ) is formed in at least a portion of each of the first gas supply passages 121 .

The multiple second gas supply paths 122 connect the second gas diffusion chamber 102 to the multiple second openings 112. That is, each of the second gas supply paths 122 connects the corresponding second opening 112 to the second gas diffusion chamber 102.

Specifically, the partial window 21 is configured by stacking a first plate 201, a second plate 202, and a third plate 203 in this order from above.

As shown in FIGS. 2 and 3, a recess 211 is formed in the lower surface of the first plate 201, and the recess 211 is closed by the second plate 202 to form the first gas diffusion space 101.
Similarly, as shown in Figures 2 and 4, a recess 221 is formed in the lower surface of the second plate 202, and this recess 221 is blocked by the third plate 203 to form the second gas diffusion chamber 102.

Also, as shown in FIG. 2, a first process gas inlet 131 and a second process gas inlet 132 are formed on the upper surface of the first plate 201.

The inlet 131 communicates with the first gas diffusion space 101 via a first gas inlet path 141. The first gas inlet path 141 is formed so as to extend in the vertical direction and penetrate the first plate 201.
In the illustrated example, the number of inlets 131 is one, but the number may be two or more.

The inlet 132 is connected to the second gas diffusion chamber 102 via the second gas introduction path 142. The second gas introduction path 142 is formed to extend in the vertical direction. The second gas introduction path 142 is also formed to straddle the first plate 201 and the second plate 202 and pass through the first gas diffusion chamber 101. The portion of the second gas introduction path 142 that passes through the first gas diffusion chamber 101 is provided with an induction pipe 212 whose hollow portion forms the second gas introduction path 142. This prevents the first process gas in the first gas diffusion chamber 101 from mixing with the second gas introduction path 142. The induction pipe 212 is provided to penetrate the first gas diffusion chamber 101 in the vertical direction.

In the illustrated example, there is one inlet 132 and one guide pipe 212, but there may be two or more.

Furthermore, the aforementioned multiple first gas supply paths 121 and multiple second gas supply paths 122 are each formed to extend in the vertical direction.

Each of the first gas supply paths 121 is formed to straddle the second plate 202 and the third plate 203 and pass through the second gas diffusion chamber 102. A guide pipe 222, whose hollow portion forms the first gas supply path 121, is provided in the portion of the first gas supply path 121 that passes through the second gas diffusion chamber 102. The guide pipe 222 is provided to penetrate the second gas diffusion chamber 102 in the vertical direction. In this embodiment, the guide pipe 222 is formed to protrude from the lower surface of the second plate 202, but a part or all of it may be formed to protrude from the upper surface of the third plate 203. In addition, in the example shown in the figure, the aforementioned narrow passage 121a is formed inside the guide pipe 222. However, the narrow passage 121a may be formed partly or entirely outside the guide pipe 222.

Each of the second gas supply passages 122 is formed to penetrate the third plate 203.

Furthermore, the aforementioned multiple first openings 111 and multiple second openings 112 are arranged in a staggered manner on the underside of the third plate 203, as shown in FIG. 5.

The number of the guide tubes 212 is less than the number of the guide tubes 222. This makes the first gas diffusion chamber 101 larger than the second gas diffusion chamber 102. The first process gas, SiH ₄ gas, is less likely to diffuse than the second process gas, O ₂ gas, because the supply flow rate to each partial window 21 during plasma processing is lower. However, in this embodiment, the first gas diffusion chamber 101 that diffuses the first process gas is larger than the second gas diffusion chamber 102 as described above, so that the first process gas can be diffused in the same manner as the second process gas even if the supply flow rate is low.

Each of the first to third plates 201 to 203 is made of, for example, a non-magnetic conductive material (such as aluminum). When a corrosive gas is used as the first process gas, the following portions that come into contact with the first process gas may be coated with a corrosion-resistant coating such as anodizing to improve corrosion resistance.
That is,
A surface of the first plate 201 that forms the first gas introduction path 141;
Surfaces of the first plate 201 and the second plate 202 that form the first gas diffusion space 101;
Surfaces of the second plate 202 and the third plate 203 that form the first gas supply path 121;
The lower surface of the third plate 203 facing the processing space S1 may be coated with a corrosion-resistant coating. Furthermore, the lower surface of the third plate 203 is coated with a plasma-resistant coating such as a coating process with ceramic such as yttrium oxide in order to improve plasma resistance.

Furthermore, at least a portion of the above-mentioned parts that come into contact with the first processing gas may be made of stainless steel parts.

The second plate 202 is fastened to the first plate 201 by fastening screws (not shown), and the third plate 203 is also fastened to the second plate 202 by fastening screws (not shown).

In addition, O-rings (not shown) for sealing the first processing gas and the second processing gas are provided at the portions where the first plate 201 and the second plate 202 contact each other and at the portions where the second plate 202 and the third plate 203 contact each other.

FIG. 6 is a diagram for explaining the dimensions of the narrow passage 121a of the first gas supply passage 121. As shown in FIG.
As described above, a narrow passage 121a is formed in the first gas supply path 121. By increasing the aspect ratio (L1/R1) of the length L1 to the width (specifically, diameter) R1 of the narrow passage 121a, it is possible to prevent the second process gas ejected from the second opening 112 from flowing back through the first gas supply path 121 including the narrow passage 121a and being mixed into the first gas diffusion chamber 101. In this embodiment, the aspect ratio is 10 or more.
In addition, since it is difficult to increase the above aspect ratio by adjusting the length L of the narrow passage 121a from the viewpoint of preventing the device from becoming too large, the aspect ratio is set to 10 or more by narrowing the diameter R1 of the narrow passage 121a.

In this embodiment, a narrow passage 122a is also formed at the lower end of the second gas supply path 122. The narrow passage 122a may also have an aspect ratio (L2/R2) of its length L2 to its width R2 of 10 or more.

<Substrate processing>
Next, substrate processing in the plasma processing apparatus 1 will be described.
First, under the control of the controller U, the gate valve 12 is opened, and the substrate G is loaded into the processing space S1 through the load/unload port 11 and placed on the substrate support part 30. Thereafter, the gate valve 12 is closed.

Subsequently, under the control of the control unit U, _SiH4 gas as a first processing gas and _O2 gas as a second processing gas are simultaneously and individually supplied into the processing space S1 from the first and second openings 111 and 112 of each partial window 21. In addition, the processing space S1 is evacuated by the exhaust unit 50, and the inside of the processing space S1 is adjusted to a desired pressure.
At this time, the control unit U performs control so as to satisfy the following conditions (1) to (3). Specifically, the control unit U controls the first supply mechanism 62, the second supply mechanism 65, and the exhaust unit 50 based on the measurement results of the pressure gauge 90, etc. so as to satisfy the following conditions (1) to (3).

(1) The pressure difference between the first gas diffusion chamber 101 and the processing space S1 is 47 Pa or more.
(2) The gas flow rate through each of the plurality of first gas supply paths 121 is higher than the gas flow rate through each of the plurality of second gas supply paths 122 .
(3) The gas flow rate for each of the plurality of first gas supply paths 121 is 0.15 sccm or more.

In addition, in order to satisfy the above condition (1), the control unit U performs control to satisfy the following condition (4), and specifically, controls the first supply mechanism 62, the second supply mechanism 65, and the exhaust unit 50 to satisfy the following condition (4).
(4) The pressure in the processing space S1 is 1 Pa to 5 Pa (preferably 1.3 to 4.0 Pa).

Next, under the control of the control unit U, the substrate G is subjected to a film forming process as a process. Specifically, under the control of the control unit U, high frequency power is supplied from the high frequency power supply 41 to the high frequency antenna 80, which generates an induced electric field in the processing space S1 through the metal window 20. As a result, the induced electric field converts the SiH ₄ gas and O ₂ gas in the processing space S1 into plasma, generating high-density inductively coupled plasma, and a SiO film is formed on the substrate G.
During the deposition of the SiO film by plasma, the control unit U also performs control so as to satisfy the above conditions (1) to (3).

After the film formation is completed, under the control of the control unit U, the power supply from the high frequency power supply 41 and the supply of the processing gas through the partial window 21 are stopped, and the _SiH4 gas and _O2 gas are exhausted from the processing space S1 by the exhaust unit 50. Then, the substrate G is unloaded in the reverse order to that of the loading.
This completes the series of substrate processing steps.

<Simulation>
The inventors performed a simulation of the ratio of _O2 gas, which is among the SiH4 gas and _O2 gas independently supplied to the processing space S1 from the partial window 21 configured as described above, flowing back into the first gas diffusion chamber 101 in the partial window 21 and being mixed with _{the SiH4} gas, that is, the back diffusion of _O2 gas. The results are shown in Figures 7 to 9. Note that the following simulations A to C are common in that the number of the first gas supply path 121 and the number of the second gas supply path 122 are one each, and that the diameter R2 of the narrow path 122a of the second gas supply path 122 is 1 mm and the length L2 is 5 mm.

(Simulation A)
In simulation A, the effect of the flow rate of the first process gas, _SiH4 gas, on the back diffusion of the second process gas, _O2 gas, was verified. In simulation A, the flow rate ratio of _SiH4 gas to _O2 gas was set to 1:10, and the diameter R1 of the narrow passage 121a of the first gas supply path 121 was set to 0.8 mm, the length L1 was set to 8 mm, and the aspect ratio was set to 10.

7, according to simulation A, even if the flow rate ratio of SiH ₄ gas and O ₂ gas is the same at 1:10, the higher the flow rate of SiH ₄ gas, the larger the differential pressure between the first gas diffusion chamber 101 and the processing space S1. Also, the higher the flow rate of SiH ₄ gas, the lower the upper stage mixing rate, i.e., the mixing rate of O ₂ gas into the first gas diffusion chamber 101. Specifically, when the flow rate of SiH ₄ gas is 0.2 sccm or more, the differential pressure exceeds 46.7 Pa and the upper stage mixing rate falls below the target value of 2%, whereas when the flow rate of SiH ₄ gas is low at 0.1 sccm, the differential pressure is low at about 34.5 and the upper stage mixing rate greatly exceeds the target value of 2.0%.
The lower mixing rate, i.e., the mixing rate of _SiH4 gas into the second gas diffusion space 102, was 0% regardless of the flow rate of _SiH4 gas.

(Simulation B)
In simulation B, when the flow rate ratio of _SiH4 gas to _O2 gas is 1:10 and the flow rate of _SiH4 gas is low at 0.1 sccm, resulting in a large upper-stage mixing rate, it was verified whether the upper-stage mixing rate could be improved by increasing the aspect ratio of the narrow passage 121a of the first gas supply path 121. In addition, in simulation B, the length L1 of the narrow passage 121a was fixed at 8 mm.

As shown in FIG. 8, according to simulation B, by increasing the aspect ratio of the narrow passage 121a, the pressure difference with the processing space S1 of the first gas diffusion chamber 101 increased, and the upper-stage mixing rate decreased. Specifically, when the aspect ratio was 27, the upper-stage mixing rate was 1/4.4 compared to when the aspect ratio was 10. This is because the pressure difference at both ends of the narrow passage 121a increases as the aspect ratio increases. However, the upper-stage mixing rate was still above 2%.

Also, according to the results of the simulations A and B, it is presumed that the flow rate of the SiH ₄ gas has a greater effect on the upper-stage mixing ratio than the aspect ratio of the narrow passage 121a.
The lower mixing rate was 0%, regardless of the aspect ratio of the narrow passage 121a.

(Simulation C)
In this simulation C, the change in the upper mixing ratio when only the flow rate of _SiH4 gas is changed without changing the flow rate of _O2 gas was verified. In this simulation C, the flow rate of _O2 gas was 1 sccm, the diameter R1 of the narrow passage 121a of the first gas supply path 121 was fixed at 0.3 mm, the length L1 was fixed at 8 mm, and the aspect ratio was fixed at 27.
As shown in FIG. 9, according to simulation C, by increasing the flow rate of _SiH4 gas from 0.1 sccm to 0.15 sccm without changing the flow rate of _O2 gas, the pressure difference between the first gas diffusion chamber 101 and the processing space S1 becomes large, and the upper-stage mixing rate becomes 2.0% or less, and further falls below the higher target value of 1.0%, specifically, falls to 0.40%.

According to the simulations A to C, if the flow rate of the SiH ₄ gas is 0.15 sccm, even if the aspect ratio of the narrow passage 121a is 10, the pressure difference in the first gas diffusion chamber 101 will not be 47 Pa or more, but the upper mixing rate will be about 1.76% (0.4×10.2/2.3), which is estimated to be less than the target value of 2.0%. The estimated value is calculated by comparing the results of the simulation B with the aspect ratios of 10 and 27 and the result of the simulation C with the flow rate of the SiH ₄ gas being 0.15 sccm.
The lower-stage contamination rate was 0% regardless of the flow rate of SiH ₄ gas.

(Other simulations)
In addition, the present inventors have verified the influence of the aspect ratio of the narrow passage 121a on the upper-stage mixing rate when _N2 gas is used instead of _O2 gas as the second process gas, the flow rate of _N2 gas is set to 3.8 sccm, and the flow rate of _SiH4 gas is increased to 0.4 sccm.
In this simulation, since the flow rate of _SiH4 gas is quite large at 0.4 sccm, it is predicted that even if the aspect ratio of the narrow passage 121a is small, the pressure difference with the processing space S1 of the first gas diffusion chamber 101 is large and the upper stage mixing rate is low. However, according to the simulation results, when the aspect ratio of the narrow passage 121a is small at 5, the pressure difference is large at about 45 Pa, but the upper stage mixing rate is high at 1.5%. In contrast, when the aspect ratio of the narrow passage 121a is 10, the pressure difference is large at about 75 Pa and the upper stage mixing rate is low at 0.04%.

Based on the above simulation results, in this embodiment,
The aspect ratio of the length L1 to the width R1 of the narrow passage 121a of the first gas supply passage 121 is set to 10 or more;
Control is performed so that the pressure difference between the first gas diffusion chamber 101 and the processing space S1 is 47 Pa or more, and the amount of gas per each of the plurality of first gas supply paths 121 is 0.15 sccm or more.
Therefore, it is possible to reduce the upper mixing rate, i.e., the mixing rate of the second process gas (specifically, _O2 gas) into the first gas diffusion chamber 101. In other words, it is possible to further suppress the second process gas ejected into the processing space S1 from flowing back through the first gas supply path 121 including the narrow path 121a and mixing into the first gas diffusion chamber 101. Therefore, it is possible to suppress the occurrence of a risk caused by the mixing of the first process gas and the second process gas.

<Modification>
In the above example, _O2 gas is used as the combustion supporting gas for forming the SiO film. However, _N2O gas may be used instead, or a mixture of _O2 gas and _N2O gas may be used.
The first process gas and the second process gas may be used for forming a film other than a SiO film, for example, a SiN film.

The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. The above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

REFERENCE SIGNS LIST 1 Plasma processing apparatus 10 Vessel body 14 Metal frame 20 Metal window 21 Partial window 30 Substrate support portion 101 First gas diffusion chamber 102 Second gas diffusion chamber 111 First opening 112 Second opening 121 First gas supply path 121a Narrow passage 122 Second gas supply path G Glass substrate S1 Processing space U Control portion

Claims (9)

A substrate processing apparatus for processing a substrate with a first gas and a second gas,
a processing vessel having a processing space therein in which the processing is performed on the substrate;
a shower head that supplies the first gas and the second gas independently to the processing space;
A control unit,
The shower head comprises:
a first gas diffusion chamber for diffusing the first gas, and a second gas diffusion chamber arranged below the first gas diffusion chamber for diffusing the second gas,
a plurality of first openings for ejecting the first gas and a plurality of second openings for ejecting the second gas on a lower surface;
a plurality of first gas supply paths that communicate between the first gas diffusion chamber and the plurality of first openings, and a plurality of second gas supply paths that communicate between the second gas diffusion chamber and the plurality of second openings,
the control unit performs control so that a pressure difference between the first gas diffusion chamber and the processing space is 47 Pa or more and a gas flow rate per one of the plurality of first gas supply paths is 0.15 sccm or more;
A narrow passage is provided in at least a portion of each of the first gas supply paths;
The narrow passage has an aspect ratio of length to width of 10 or more. an induction tube penetrating the second gas diffusion chamber;
The substrate processing apparatus of claim 1 , wherein the induction pipes form a part of each of the first gas supply paths. The substrate processing apparatus according to claim 1 or 2, wherein one of the first gas and the second gas is a combustible gas, and the other is a combustion-supporting gas. The substrate processing apparatus of claim 3, wherein the first gas is a flammable gas and the second gas is a combustion-supporting gas. Further comprising a plasma generating means,
5. The substrate processing apparatus according to claim 1, wherein a film forming process is performed as the process by using plasma generated from the first gas and the second gas by the plasma generating means. 1. A substrate processing method for processing a substrate with a first gas and a second gas using a substrate processing apparatus, comprising:
The substrate processing apparatus includes:
a processing vessel having a processing space therein in which the processing is performed on the substrate;
a shower head that supplies the first gas and the second gas independently to the processing space;
The shower head comprises:
a first gas diffusion chamber for diffusing the first gas, and a second gas diffusion chamber arranged below the first gas diffusion chamber for diffusing the second gas,
a plurality of first openings for ejecting the first gas and a plurality of second openings for ejecting the second gas on a lower surface;
a plurality of first gas supply paths that communicate between the first gas diffusion chamber and the plurality of first openings, and a plurality of second gas supply paths that communicate between the second gas diffusion chamber and the plurality of second openings,
A narrow passage is provided in at least a portion of each of the first gas supply paths;
The aspect ratio of the length to the width of the narrow passage is 10 or more;
a pressure difference between the first gas diffusion chamber and the processing space being controlled to be 47 Pa or more, and a gas flow rate per each of the plurality of first gas supply paths being controlled to be 0.15 sccm or more, and the substrate being subjected to the processing. The substrate processing method according to claim 6, wherein one of the first gas and the second gas is a combustible gas and the other is a combustion-supporting gas. The substrate processing method according to claim 7, wherein the first gas is a combustible gas and the second gas is a combustion-supporting gas. The substrate processing apparatus further includes a plasma generating means,
9. The substrate processing method according to claim 6, wherein a film forming process is carried out as the process by using plasma generated from the first gas and the second gas by using the plasma generating means.