JP2002164320A - Substrate-treating apparatus and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate-treating apparatus for treating a substrate by vapor containing acid in a stable composition, and to provide a substrate treatment method. SOLUTION: Fluoric acid vapor is generated by a fluoric acid generation container 10, and is supplied to a substrate treatment chamber 10 via a treatment gas supply path 40. The treatment gas supply path 40 includes a pressure adjustment valve 50. The opening of the pressure adjustment valve 50 is controlled by a controller 53 so that pressure at the upstream side turns into a pressure for satisfying azeotropic conditions in the fluoric acid generation container 10. Before the fluoric acid vapor is supplied to a substrate treatment chamber 20, valves 71 and 81 are closed, and a carrier gas is supplied to a substrate treatment chamber 20 via a bypass path 75 and a treatment gas supply path 40. The opening control of the pressure adjustment valve 50 is started from this point.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a process for treating a substrate (in particular, by introducing a vapor containing an acid such as hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid (including HF and anhydrous HF), acetic acid, etc.) to the surface of the substrate. The present invention relates to a substrate processing apparatus and a substrate processing method for performing a process for removing a film on the surface of a substrate by a so-called vapor phase etching process. Substrates to be processed include various substrates such as semiconductor wafers, glass substrates for liquid crystal displays and plasma displays, and substrates for optical, magnetic and magneto-optical disks. The material of the substrate includes materials such as silicon, glass, resin, and ceramic. The removal of the film on the substrate surface may be for the purpose of selectively removing a part or all of the predetermined film, or may be for the purpose of cleaning the substrate surface.

[0002]

2. Description of the Related Art In a semiconductor memory manufacturing process, when a memory capacitor film is formed on a semiconductor wafer (hereinafter, referred to as a "wafer"), BSG (Boron-Silicate Glacier) is used.
ss), PSG (Phospho-Silicate Glass), BPSG
(Boron-doped Phospho-SilicateGlass) or another oxide film containing a large amount of impurities is used as a sacrificial oxide film. These sacrificial oxide films can have a large selectivity with respect to a thermal oxide film or a CVD (chemical vapor deposition) oxide film in etching using hydrofluoric acid vapor, and the thermal oxide film or the CVD oxide film is used as an etching stopper film. And can be selectively removed.

The etching selectivity in the etching process using hydrofluoric acid vapor depends on the temperature. For example, the etching rate of a thermal oxide film sharply decreases with a rise in temperature, whereas the BPSG film maintains a relatively high etching rate regardless of a temperature change. Therefore, when the BPSG film on the thermal oxide film formed on the surface of the wafer is selectively removed, a gas phase etching process using hydrofluoric acid vapor is performed while maintaining the temperature of the wafer at 50 ° C. to 80 ° C.

[0004] A substrate processing apparatus for performing the gas phase etching process includes a hydrofluoric acid vapor generating vessel for generating hydrofluoric acid vapor, and a processing chamber into which the hydrofluoric acid vapor generated in the hydrofluoric acid vapor generating vessel is led. It has. The hydrofluoric acid vapor generated in the hydrofluoric acid vapor generating vessel is guided to a processing chamber via a processing gas supply path by a carrier gas composed of an inert gas (generally, nitrogen gas). The processing chamber is provided with a hot plate for maintaining the wafer at a constant temperature.

The aqueous solution of hydrofluoric acid stored in the hydrofluoric acid vapor generating vessel has a concentration that gives a so-called pseudo-azeotropic composition (for example, about 39.6% at 1 atmosphere and room temperature (20 ° C.)).
Has been prepared. This pseudo-azeotropic hydrofluoric acid aqueous solution has the same evaporation rate of water and hydrogen fluoride,
Even when the hydrofluoric acid vapor in the hydrofluoric acid vapor generation vessel is reduced by the hydrofluoric acid vapor being led to the processing chamber via the processing gas supply path, the concentration of the hydrofluoric acid vapor guided to the processing chamber is kept unchanged. .

[0006]

The process of etching an oxide film with hydrofluoric acid vapor is an extremely delicate process. This process involves the adsorption of moisture on the wafer. Therefore, the reaction speed is easily affected by the wafer surface condition, and the reaction progress speed changes depending on the contamination state of the wafer surface and the state of adsorption of moisture. Therefore, there is a problem that it is difficult to obtain a stable etching rate.

Further, if the surface condition of the wafer is different on the wafer surface, it is impossible to perform uniform etching processing on the wafer surface. Further, since the surface states of a plurality of wafers are not always equal, individual differences occur in the etching process for the wafers. That is, reproducibility is not always good. Therefore, in order to improve the in-plane uniformity and reproducibility of the processing, the pressure in the processing chamber is reduced,
It has been proposed to control the moisture adsorbed on the wafer.

However, when the processing chamber is evacuated and decompressed,
The inside of the hydrofluoric acid vapor generation container is also exhausted through the processing gas supply path, and the pressure in the hydrofluoric acid vapor generation container decreases. As a result, the azeotropic conditions in the hydrofluoric acid vapor generation container are broken, and the compositions of hydrofluoric acid and water in the hydrofluoric acid aqueous solution are not equal to the compositions of hydrofluoric acid and water in the hydrofluoric acid vapor. This means that the composition of the hydrofluoric acid vapor supplied to the processing chamber fluctuates as the hydrofluoric acid aqueous solution decreases. Therefore, it is extremely difficult to achieve the desired processing on the wafer.

Further, not only the processing chamber but also the hydrofluoric acid vapor generating vessel needs to have a strong structure capable of withstanding the reduced pressure, and thus there is a problem that the cost of the vapor phase etching apparatus increases. Furthermore, during maintenance of the hydrofluoric acid vapor generating container, the pressure in the container must be returned to normal pressure, which makes the maintenance work troublesome.
On the other hand, a wafer before processing is loaded into the processing chamber, and a wafer after processing is unloaded. Therefore, a change in the pressure in the processing chamber when loading / unloading the wafer is inevitable. Therefore, regardless of whether or not the pressure in the processing chamber is reduced, the pressure in the hydrofluoric acid vapor generation vessel connected to the processing chamber via the processing gas supply path is not always stable. Therefore, even in a vapor phase etching apparatus configured to perform no depressurization, the composition in the hydrofluoric acid vapor guided to the surface of the wafer is not always stable.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a substrate processing apparatus and a substrate processing method capable of processing a substrate with a vapor containing an acid having a stable composition. Another object of the present invention is to provide a substrate processing apparatus and a substrate processing method capable of supplying a vapor containing an acid having a stable composition to a substrate regardless of whether or not the pressure in the substrate processing tank is reduced. That is.

[0011]

Means for Solving the Problems and Effects of the Invention In order to achieve the above object, the invention according to claim 1 stores an acid-containing solution (11) and generates an acid-containing vapor. A tank (10), carrier gas supply means (30, 31) for supplying a carrier gas to the acid vapor generation tank, a substrate processing tank (20) for accommodating a substrate to be processed, a vapor containing acid and a carrier A processing gas supply path (40) for introducing a processing gas, which is a mixed gas with the gas, from the acid vapor generation tank to the substrate processing tank; and a processing gas supply path interposed between the processing gas supply path and the processing gas supply path.
A pressure adjusting valve (50) capable of adjusting the opening degree; and a pressure control means (5) for adjusting the opening degree of the pressure adjusting valve to maintain the pressure in the acid vapor generation tank at a predetermined pressure.
3) A substrate processing apparatus comprising: It should be noted that the alphanumeric characters in parentheses indicate corresponding components and the like in the embodiments described later. Hereinafter, the same applies in this section.

According to the present invention, the processing gas supply path through which the processing gas, which is a mixed gas of the acid vapor and the carrier gas, is introduced is provided with the pressure adjusting valve capable of adjusting the opening. By performing the opening adjustment of the pressure adjustment valve, the pressure in the acid vapor generation tank is maintained at a predetermined pressure.
Thereby, the generation of the vapor containing the acid in the acid vapor generation tank is performed under stable conditions, so that a processing gas having a stable composition can be guided to the substrate processing tank. Thereby, substrate processing with good reproducibility can be performed.

According to a second aspect of the present invention, the apparatus further comprises pressure reducing means (90, 91) for evacuating the substrate processing tank during substrate processing to reduce the pressure in the substrate processing tank. Item 2. A substrate processing apparatus according to Item 1. According to the present invention, the pressure in the substrate processing tank is reduced during the processing of the substrate, so that the moisture adsorbed on the substrate surface can be controlled well. Therefore, the processing of the substrate surface with the processing gas can be uniformly performed in the substrate surface, and the surface processing with good reproducibility can be performed on a plurality of substrates.

Further, even during the period when the pressure in the substrate processing tank is reduced, the pressure in the acid vapor generating tank is not reduced. Therefore, the acid vapor generating tank does not need to have a strong structure capable of withstanding the reduced pressure. Thus, the cost of the substrate processing apparatus can be reduced. Furthermore, if the pressure in the acid vapor generation tank is maintained at, for example, normal pressure, it is not necessary to perform an operation of returning the internal pressure to normal pressure during maintenance of the acid vapor generation tank. Thereby, the maintenance work of the acid vapor generation tank can be simplified.

Incidentally, a forced exhaust mechanism such as a vacuum pump, an exhaust blower or an ejector can be applied to the pressure reducing means. In the invention according to claim 3, the predetermined pressure is:
3. The substrate processing apparatus according to claim 1, wherein the pressure is set to satisfy an azeotropic condition between the acid and the solvent in the solution containing the acid stored in the acid vapor generation tank. 4.
According to the present invention, it is possible to satisfy the azeotropic condition in the acid vapor generation tank regardless of the fluctuation of the pressure in the substrate processing tank. Thereby, even if the solution containing the acid stored in the acid vapor generation tank is reduced by evaporation, the composition of the acid and the solvent in the vapor is kept constant. Thereby, the reproducibility of the processing for the substrate processed in the substrate processing tank can be improved.

According to a fourth aspect of the present invention, the carrier gas from the carrier gas supply means bypasses the acid vapor generation tank and is introduced into the processing gas supply path upstream of the pressure regulating valve. 75), an acid vapor supply control valve (81) for shutting off between the acid vapor generation tank and the processing gas supply path, and the pressure control means with the acid vapor supply control valve closed. Valve opening / closing control means (53) for opening the acid vapor supply control valve after the opening of the pressure adjustment valve is adjusted so that the pressure upstream of the pressure adjustment valve becomes the predetermined pressure.
The substrate processing apparatus according to claim 1, further comprising:

According to the present invention, after the pressure upstream of the pressure regulating valve in the processing gas supply path reaches a predetermined pressure, the acid vapor supply control valve is opened, and the acid vapor generation tank and the processing gas supply path are connected. Communicate. Therefore, when the supply of the acid vapor is started, the opening of the pressure regulating valve is promptly led to an opening that can maintain the pressure in the acid vapor generating tank at the predetermined pressure. That is, at the time of supply of the carrier gas through the bypass path, by performing training for adjusting the opening degree of the pressure adjustment valve in advance, the opening adjustment amount of the pressure adjustment valve after starting the supply of steam containing acid is reduced. can do. Thus, the pressure in the acid vapor generation tank can be maintained at the above-mentioned predetermined pressure during almost all the period in which the vapor containing the acid is supplied to the substrate processing tank. Therefore, it is possible to further stabilize the composition of the vapor containing the acid introduced into the substrate processing tank.

The functions of the valve opening / closing control means and the pressure control means may be realized by different software portions executed by common hardware (microcomputer or the like) or may be realized by different hardware configurations. . The invention according to claim 5 includes a step of generating an acid vapor in an acid vapor generation tank storing a solution containing an acid,
Guiding the acid-containing vapor from the acid vapor generation tank to the substrate processing tank and processing the substrate in the substrate processing tank; and performing the processing of the substrate by introducing the acid-containing vapor to the substrate processing tank. Controlling the pressure in the acid vapor generation tank to a predetermined pressure independently of the substrate processing tank during a substrate processing period (T4).

According to this method, the effect related to claim 1 can be achieved. Further, this method can be specifically implemented by the configuration described in claim 1. Further, in connection with this method, it is also possible to make modifications as described in claims 2 to 4.

[0020]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is an illustrative sectional view for explaining a configuration of a substrate processing apparatus according to one embodiment of the present invention. This apparatus has a basic configuration as a vapor phase etching apparatus for removing an oxide film formed on the surface of a semiconductor wafer (hereinafter, simply referred to as “wafer”) W. More specifically, for example, when a sacrificial oxide film (BPSG film or the like) used for forming a memory capacitor is formed on a thermal oxide film formed on wafer W, this sacrificial oxide film is It is a device for selective removal. For this process, in this substrate processing apparatus, a film removing step is performed by supplying a vapor of hydrofluoric acid to the surface of the wafer W, thereby performing a gas phase etching process of hydrofluoric acid.

This substrate processing apparatus stores a hydrofluoric acid aqueous solution 11 and a hydrofluoric acid vapor generating container 10 having a closed structure for generating a vapor of the hydrofluoric acid aqueous solution, a substrate processing chamber 20 for accommodating a wafer W, and a hydrofluoric acid solution. A carrier gas supply path 30 for supplying a carrier gas composed of an inert gas (generally, nitrogen gas) to the acid vapor generation vessel 10;
A processing gas supply path 40 for guiding a processing gas, which is a mixture of hydrofluoric acid vapor and carrier gas from the substrate processing chamber 20, to the substrate processing chamber 20, where the substrate processing chamber 20 and the hydrofluoric acid vapor generating vessel 10 And a pressure adjusting valve 50 interposed therebetween. An inert gas supply source 31 that supplies an inert gas as a carrier gas is connected to the carrier gas supply path 30. A flow control device (MFC) 32 is provided at an intermediate portion of the carrier gas supply path 30.

A carrier gas introduction channel 61 is formed between the carrier gas supply channel 30 and the hydrofluoric acid vapor generation container 10, and the hydrofluoric acid vapor generation container 10 and the processing gas supply channel 40 are formed.
A processing gas lead-out passage 62 through which the processing gas from the hydrofluoric acid vapor generation container 10 is led is formed between the processing gas outlet path and the processing gas outlet path 62. A first carrier gas supply control valve 71 and a first processing gas supply control valve 81 are interposed in the carrier gas introduction path 61 and the processing gas outlet path 62, respectively.

In the carrier gas introduction path 61, a position upstream of the first carrier gas supply control valve 71 in the carrier gas supply direction,
A bypass path 75 is formed between the processing gas supply control valve 81 and a position downstream of the processing gas supply control valve 81 in the processing gas supply direction. That is, the bypass path 75 bypasses the hydrofluoric acid vapor generation container 10 and connects the carrier gas supply path 30 and the processing gas supply path 40. This bypass path 75
Is provided with a second carrier gas supply control valve 72.

The pressure regulating valve 50 is an air operated valve having durability against hydrofluoric acid vapor. This pressure adjusting valve 50 is provided with an electropneumatic regulator 51.
It is actuated by pressure-adjusted compressed air supplied from the air conditioner, and its opening degree is adjusted. Compressed air from a compressed air supply source 52 is supplied to the electropneumatic regulator 51. The electropneumatic regulator 51 has a controller 5 that performs, for example, PID (proportional-integral-derivative) control.
3 is provided.

The controller 53 includes a pressure adjusting valve 5
An output signal of a pressure gauge 54 for detecting the pressure in the processing gas supply path 40 is provided on the upstream side of the processing gas supply direction from 0. The controller 53 supplies a control signal to the electropneumatic regulator 51 so that the pressure detected by the pressure gauge 54 becomes a predetermined pressure (for example, 1 atm). As a result, the opening of the pressure adjusting valve 50 is controlled so that the pressure upstream of the pressure adjusting valve 50 in the processing gas supply direction becomes the predetermined pressure.

In the processing gas supply path 40, between the pressure regulating valve 50 and the substrate processing chamber 20, a substrate processing chamber 20 is provided.
A second processing gas supply control valve 82 for controlling the supply of the processing gas to the second processing gas is provided. Although not shown, the hydrofluoric acid vapor generating vessel 10 has a hydrofluoric acid supply pipe for supplying the hydrofluoric acid solution 11 to the hydrofluoric acid vapor generating vessel 10, and a hydrofluoric acid vapor generating vessel 10. Drain pipe for discharging the hydrofluoric acid solution 11 and the hydrofluoric acid solution 1 excessively stored in the hydrofluoric acid vapor generating vessel 10
An overflow pipe or the like for overflowing 1 is connected.

In the substrate processing chamber 20, a hot plate 21 on which the wafer W is placed is provided. The hot plate 21 raises the temperature of the wafer W, for example, from 40 ° C.
The temperature is controlled to a predetermined temperature in the range of 80 ° C. to provide a temperature condition suitable for the selective etching of the oxide film with hydrofluoric acid vapor. The hot plate 21 is rotated around a vertical axis by a rotation drive mechanism 22, thereby improving the in-plane uniformity of the surface treatment of the wafer W.

A vacuum pump 90 is connected to the substrate processing chamber 20 via an exhaust path 91. An exhaust control valve 92 is interposed in the exhaust path 91. By opening the exhaust control valve 92, the inside of the substrate processing chamber 20 can be exhausted to reduce the pressure. Thus, the adsorption of moisture on the surface of the wafer W can be controlled well, and the gas phase etching process using hydrofluoric acid vapor can proceed under favorable conditions. An inert gas supply source 3 is provided in the substrate processing chamber 20.
The inert gas (carrier gas) from 1 can be supplied via a carrier gas supply path 100. The carrier gas supply path 100 is a carrier gas supply path 3
A carrier gas supply path of a different system from that of the process gas supply path 40 and the processing gas supply path 40 is formed, and a carrier gas supply control valve 101 is interposed in the middle thereof. The carrier gas supply control valve 101 is opened to purge the inside of the substrate processing chamber 20 with an inert gas when unloading the processed wafer W from the substrate processing chamber 20.

The controller 53 comprises, for example, a microcomputer. In this embodiment, in addition to the control of the electropneumatic regulator 51, the valves 71, 72, 8
1, 82, 92 and 101 are also controlled to open and close. The hydrofluoric acid aqueous solution 11 stored in the hydrofluoric acid vapor generating vessel 10 has a concentration of a so-called pseudo-azeotropic composition (for example, about 39.6 at 1 atmosphere and room temperature (20 ° C.)).
%). The hydrofluoric acid aqueous solution 11 having the pseudo-azeotropic composition can be used as long as the pressure in the hydrofluoric acid vapor generation container 10 satisfies the azeotropic condition in the pseudo-azeotropic composition, that is, for example, the pressure in the hydrofluoric acid vapor generation container 10 Is maintained at 1 atm, the evaporation rates of water and hydrogen fluoride are equal. Therefore, the processing gas outlet path 62
Even if the hydrofluoric acid aqueous solution 11 is reduced by the introduction of the hydrofluoric acid vapor into the substrate processing chamber 20 through the processing gas supply path 40, the processing gas supply path 40
The composition of the hydrofluoric acid vapor leading to zero is kept unchanged.

In this embodiment, the controller 53
The opening of the pressure regulating valve 50 is controlled via the electropneumatic regulator 51 so that the pressure gauge 54 detects a pressure at which the azeotropic condition in the hydrofluoric acid vapor generating vessel 10 is satisfied, that is, for example, 1 atm. As a result, the evaporation of water and hydrogen fluoride in the hydrofluoric acid vapor generating vessel 10 proceeds at the same speed regardless of the pressure change in the substrate processing chamber 20. In other words, the substrate processing chamber 20 is evacuated by the vacuum pump 90, whereby the gaseous phase etching process using the processing gas proceeds under the condition that the internal pressure of the substrate processing chamber 20 is reduced. The azeotropic conditions at 10 are maintained. Thereby, the wafer W can be subjected to the gas phase etching process with hydrofluoric acid vapor having a desired composition, and the reproducibility of the process for a plurality of wafers W is improved.

Since the pressure in the hydrofluoric acid vapor generating vessel 10 is not reduced even during the period in which the pressure in the substrate processing chamber 20 is reduced, the hydrofluoric acid vapor generating vessel 10 has a strong structure that can withstand the reduced pressure. You do not need to be. Therefore, the cost of the substrate processing apparatus can be reduced. Further, since the pressure in the hydrofluoric acid vapor generating container 10 may be maintained at, for example, normal pressure (1 atm), it is necessary to perform an operation of returning the internal pressure to normal pressure during maintenance of the hydrofluoric acid vapor generating container 10. There is no. Therefore, maintenance work can be simplified.

FIG. 2 is a time chart for explaining the operation of the above-mentioned substrate processing apparatus, and the valves 50, 71, 72, 81, 82, 92, 101 by the controller 53 are shown.
Is shown. FIG. 2A shows the opening / closing operation of the first carrier gas supply control valve 71, and FIG.
2 (b) shows the opening and closing operation of the first processing gas supply control valve 81, and FIG. 2 (c) shows the second carrier gas supply control valve 72.
2 (d) shows the opening and closing operation of the second processing gas supply control valve 82, and FIG. 2 (e) shows the opening and closing operation of the exhaust control valve 92. FIG. 2F shows the control state of the pressure regulating valve 50, and FIG. 2G shows the open / close state of the carrier gas supply control valve 101.

In a wafer loading period T1 in which an unprocessed wafer W is loaded into the substrate processing chamber 20 by a substrate transfer robot (not shown), the valves 71, 72, 81, 82, 9 are provided.
2 and 101 are in a closed state, and the opening of the pressure adjusting valve 50 is not adjusted. When the transfer of the wafer W is completed, the process enters a processing chamber decompression period T2 in which the pressure in the substrate processing chamber 20 is reduced. During this period T2, the exhaust control valve 9
Only 2 is switched to the open state. by this,
The inside of the substrate processing chamber 20 is evacuated by a vacuum pump 90,
The internal pressure will decrease.

When the pressure in the substrate processing chamber 20 is reduced to a predetermined constant pressure, a pre-purge period T3 for replacing the atmosphere in the substrate processing chamber 20 starts. In the pre-purge period T3, the second carrier gas supply control valve 72 and the second processing gas supply control valve 82 are switched to the open state. At this time, the exhaust control valve 92 is kept open, and the pressure in the substrate processing chamber 20 is continuously reduced. During the pre-purge period T3, the carrier gas controlled to the target flow rate by the flow rate control device 32 is guided to the substrate processing chamber 20 via the carrier gas supply path 30, the bypass path 75, and the processing gas supply path 40. Thereby, the atmosphere in the substrate processing chamber 20 is replaced with an inert gas atmosphere.

In the pre-purge period T3,
The opening control of the pressure regulating valve 50 is started. That is, the controller 53 controls the pressure regulating valve 50 so that the pressure upstream of the pressure regulating valve 50 in the processing gas supply direction in the processing gas supply path 40 becomes a pressure satisfying the azeotropic condition in the hydrofluoric acid vapor generating vessel 10. Control the opening. At this time, the first carrier gas supply control valve 71 and the first processing gas supply control valve 81 are closed, so that the hydrofluoric acid vapor generation container 10 is disconnected from the processing gas supply path 40. Pre-purge period T3
The purpose of the opening control of the pressure adjusting valve 50 in the above is to minimize the opening adjusting width of the pressure adjusting valve 50 at the beginning when the valves 71 and 81 are opened to start supplying the hydrofluoric acid vapor. That is, the training of the opening control of the pressure regulating valve 50 is performed using the bypass path 75 before the supply of the hydrofluoric acid vapor is started.

After the pre-purge period T3, a vapor supply period T4 for supplying hydrofluoric acid vapor to the substrate processing chamber 20 via the processing gas supply path 40 is started. This steam supply period T
In 4, the second carrier gas supply control valve 72 interposed in the bypass path 75 is closed, and the first carrier gas supply control valve 71 and the first processing gas supply control valve 81 are switched to the open state. . The valves 82 and 92 are kept open and the pressure regulating valve 5
The control of the opening degree of 0 is continuously performed.

When the switching between the open and closed states of the valves 71, 72, 81 is completed, the carrier gas whose flow rate is controlled by the flow control device 32 generates hydrofluoric acid vapor through the carrier gas supply passage 30 and the carrier gas introduction passage 61. It is led to the container 10. Then, the mixed gas of the carrier gas and the hydrofluoric acid vapor is guided to the processing gas supply path 40 via the processing gas outlet path 62, and is introduced from the processing gas supply path 40 into the substrate processing chamber 20.

The training of the opening control of the pressure regulating valve 50 during the pre-purge period T3 allows the opening of the pressure regulating valve 50 to quickly satisfy the azeotropic condition of the hydrofluoric acid vapor generation vessel 10 with a small adjustment width. It leads to a possible opening. As a result, in the hydrofluoric acid vapor generation vessel 10, hydrogen fluoride and water evaporate at the same evaporation rate, and the processing gas containing hydrofluoric acid vapor having a stable composition is supplied to the substrate processing chamber 2
The wafer W is guided to the zero wafer W.

When the supply of the processing gas is performed for a predetermined period of time, the process proceeds to a post-purge period T5, where a post-purge for replacing the internal atmosphere of the substrate processing chamber 20, the processing gas supply path 40, and the like is performed. That is, the first carrier gas supply control valve 71 and the first processing gas supply control valve 81 are switched to the closed state, and the second carrier gas supply control valve 7
2 is switched to the open state. The second process gas supply control valve 82 and the exhaust control valve 92 are kept open, and the opening control of the pressure regulating valve 50 is continued.

During this post-purge period,
The carrier gas from the carrier gas supply path 30 is guided to the substrate processing chamber 20 via the bypass path 75 and the processing gas supply path 40, and the atmosphere in the substrate processing chamber 20 is evacuated by the vacuum pump 90 via the exhaust path 91. Exhausted. In this way, the atmosphere containing the hydrofluoric acid vapor is mainly excluded from the processing gas supply path 40 and the substrate processing chamber 20. When the post-purging is completed, the second carrier gas supply control valve 72 during the process chamber decompression period T6.
And the processing gas supply control valve 82 is switched to the closed state. Then, the exhaust control valve 92 is kept in the open state, whereby the pressure in the substrate processing chamber 20 is reduced. During this processing chamber decompression period T6, the opening control of the pressure adjustment valve 50 is not performed.

After the processing atmosphere in the substrate processing chamber 20 is eliminated in this way, the exhaust control valve 92 is switched to the closed state during the inert gas leak period T7. During this period T7, the carrier gas supply control valve 101 interposed in the carrier gas supply path 100 is opened. Thus, the substrate processing chamber 20 after the processing gas atmosphere is removed is filled with the inert gas. Thereafter, the processed wafer W is unloaded from the substrate processing chamber 20 by a substrate unloading robot (not shown) in the wafer unloading period T8. During this wafer unloading period T8,
With the carrier gas supply control valve 101 closed,
The supply of the inert gas to the substrate processing chamber 20 is not performed.

While the embodiment of the present invention has been described above, the present invention can be embodied in other forms.
For example, in the above-described embodiment, hydrofluoric acid vapor is used as vapor for etching the substrate surface, but acid such as hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid (including HF and anhydrous HF), acetic acid, and the like. Any vapor containing the same can be applied for the purpose of vapor-phase etching of a substrate. For example, the etching process can be performed using the vapor of the aqueous solution containing the acid, and the etching process on the substrate surface can also be performed using the vapor in a form in which the gas containing the acid (in a gaseous state) is mixed with the steam. It can be carried out.

In the above embodiment, the bypass path 75 is provided, and training of the opening control of the pressure regulating valve 50 is performed before the supply of hydrofluoric acid vapor to the substrate processing chamber 20. Training for such opening control may be omitted. Further, in the above-described embodiment, the example in which the inside of the substrate processing chamber 20 is subjected to the gaseous phase etching process by setting the inside of the substrate processing chamber 20 to the reduced pressure atmosphere has been described. The present invention can also be applied to a vapor phase etching apparatus performed under normal pressure. Even in this case, the pressure in the hydrofluoric acid vapor generation container can be reliably maintained at a pressure satisfying the azeotropic condition, so that the reproducibility of processing for a plurality of wafers can be particularly improved.

In addition, various design changes can be made within the scope of the matters described in the claims.

[Brief description of the drawings]

FIG. 1 is an illustrative cross-sectional view for explaining a configuration of a substrate processing apparatus according to an embodiment of the present invention.

FIG. 2 is a time chart for explaining the operation of the apparatus of FIG. 1;

[Explanation of symbols]

 Reference Signs List 10 hydrofluoric acid vapor generating container 11 hydrofluoric acid aqueous solution 20 substrate processing chamber 30 carrier gas supply path 31 inert gas supply source 40 processing gas supply path 50 pressure regulating valve 51 electropneumatic regulator 52 compressed air supply source 53 controller 54 pressure gauge 61 carrier Gas introduction path 62 Processing gas outlet path 71 First carrier gas supply control valve 72 Second carrier gas supply control valve 75 Bypass path 81 First processing gas supply control valve 82 Second processing gas supply control valve 90 Vacuum pump 91 Exhaust path 92 Exhaust control valve 100 Carrier gas supply path 101 Carrier gas supply control valve W Wafer

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Go Okumura 4-chome, Horikawa-dori-Teranouchi, Kamigyo-ku, Kyoto-shi, Kyoto 1-1-1 Tenjinkitamachi Dai-Nihon Screen Manufacturing Co., Ltd. F-term (reference) 2H088 FA21 FA30 HA01 2H090 JB02 JC19 3B201 AA03 AB01 BB02 BB13 BB82 BB96 BB98 CB01 CD11 5F004 BA19 BC08 CA02 DA20 DA25 DB06

Claims (5)

[Claims] An acid vapor generating tank for storing a solution containing an acid and generating a vapor containing the acid, a carrier gas supply means for supplying a carrier gas to the acid vapor generating tank, and a substrate to be processed are housed therein. A processing gas supply path for guiding a processing gas, which is a mixed gas of a vapor containing an acid and a carrier gas, from the acid vapor generation tank to the substrate processing tank; and a processing gas supply path interposed in the processing gas supply path. A pressure adjusting valve capable of adjusting the opening degree, and a pressure control means for adjusting the opening degree of the pressure adjusting valve to maintain the pressure in the acid vapor generation tank at a predetermined pressure. Processing equipment. 2. The substrate processing apparatus according to claim 1, further comprising a decompression means for evacuating the substrate processing tank during the substrate processing to thereby reduce the pressure in the substrate processing tank. 3. The method according to claim 1, wherein the predetermined pressure is set to a pressure satisfying an azeotropic condition of an acid and a solvent in a solution containing an acid stored in the acid vapor generation tank. 3. The substrate processing apparatus according to 2. 4. A bypass path for guiding a carrier gas from said carrier gas supply means to an upstream side of said pressure regulating valve of said processing gas supply path, bypassing said acid vapor generation tank, and said acid vapor generation tank. And an acid vapor supply control valve for shutting off between the processing gas supply path and the processing gas supply path. In a state where the acid vapor supply control valve is closed, the pressure on the upstream side of the pressure regulating valve is increased by the pressure control means. The valve according to any one of claims 1 to 3, further comprising valve opening / closing control means for opening the acid vapor supply control valve after the opening of the pressure adjustment valve is adjusted to the predetermined pressure. The substrate processing apparatus according to any one of the preceding claims. 5. A step of generating an acid vapor in an acid vapor generation tank storing a solution containing an acid, and guiding the acid-containing vapor from the acid vapor generation tank to a substrate processing tank. And during the substrate processing period in which a vapor containing an acid is guided to the substrate processing tank and the substrate is being processed, the pressure in the acid vapor generating tank is independent of the substrate processing tank. And controlling the pressure to a predetermined pressure.