JP2001126994A - Substrate-treating apparatus and gas leakage detecting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a means, capable of quickly and surely detecting the leakage of a process gas from a high-temperature process chamber of a substrate-treating apparatus, if there is a leakage. SOLUTION: This substrate-treating apparatus 10, such as an epitaxial growth apparatus having a process chamber 12 into which a process gas is introduced and the interior of which is heated, comprises a pump 40 which takes a part of cooling air flowing in a passage around the processing chamber 12 for cooling the process chamber 12 and blows it directly against a gas detector 32. Since the cooling air extracted is not mixed with other air, a leakage gas will not be diluted, and can be detected surely and quickly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate processing apparatus for subjecting a substrate such as a semiconductor wafer to a heat treatment such as an epitaxial growth process or a thermal CVD process, and more particularly to detecting gas leakage from the substrate processing apparatus. Means for.

[0002]

2. Description of the Related Art When a semiconductor device is manufactured, various heat treatment processes are performed on a semiconductor wafer as a substrate to be processed. For example, when performing an epitaxial growth process, an epitaxial growth apparatus including a processing chamber whose inside is heated to a high temperature (for example, about 1200 ° C.) by a heating source such as a halogen lamp is used. A substrate support called a susceptor is provided in the processing chamber, and a semiconductor wafer is set on the susceptor.
After the inside of the chamber is heated, when a processing gas is introduced into the chamber from a gas supply port provided on a side of the processing chamber, the processing gas flowing along the wafer surface causes a thermal decomposition reaction, and a thin film, a so-called thin film, is formed on the wafer surface. An epitaxial layer is formed.

When a silicon epitaxial layer is formed, a processing gas used in such an epitaxial growth apparatus is mainly composed of trichlorosilane (SiHCl ₃ ) gas or dichlorosilane (SiH ₂ Cl ₂ ) gas, and hydrogen gas is used as a carrier. A gas used as the gas is used.

In consideration of the case where such a processing gas leaks from the processing chamber, a gas detector is usually provided around the processing chamber, and a hydrogen gas detector is provided for the above-mentioned processing gas. This is the same in other substrate processing apparatuses using a processing gas such as a CVD apparatus.

[0005]

However, conventionally,
In a substrate processing apparatus such as an epitaxial growth apparatus or a thermal CVD apparatus that heats the inside of a processing chamber to a high temperature (hereinafter referred to as a “high-temperature processing apparatus”), a gas detector is used to avoid the influence of heat transmitted from the processing chamber to the outside. It has been common to place the RMS at a location that is significantly remote from the processing chamber. Further, in the conventional general high-temperature processing apparatus, from the viewpoint of protecting the components from heat, the periphery of the processing chamber is surrounded by an enclosure, and cooling air is circulated in a space between the enclosure and the processing chamber. Therefore, the gas detector was arranged outside the air circulation path. More specifically, since the air circulation path is not a completely closed structure but has an air leakage part where cooling air leaks, a gas detector is arranged near this air leakage part, and the processing gas contained in the cooling air is Is detected to detect the presence or absence of leakage of the processing gas.

Therefore, in the conventional high-temperature processing apparatus,
There is a slight time lag in detecting an emergency gas leak from the processing chamber. In addition, when the leakage gas contained in the cooling air leaks from the air circulation path, it is further diluted by the air outside the air circulation path, so that it is necessary to use a gas detector having a high detection capability. There was also.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a means capable of promptly and surely detecting a leak of a processing gas.

[0008]

In order to achieve the above object, the present invention provides a processing chamber in which a processing gas is introduced and heated internally for processing a substrate disposed therein. An enclosure surrounding the processing chamber and a space between the enclosure and the processing chamber as part of the flow path;
An air circulation path for circulating the cooling air, a pump for taking out the cooling air from the air circulation path, and an air pump disposed outside the air circulation path, and the air discharged from the pump is sent to the detection unit. The substrate processing apparatus includes a gas detection unit configured to detect a processing gas.

In this configuration, the air circulating around the processing chamber is forcibly taken out and blown to the detecting portion of the gas detecting means, so that the presence or absence of the processing gas is detected from the air that naturally leaks. The leak of the processing gas can be detected more quickly than by the method. Further, since the processing gas in the extracted air is not diluted by the air outside the air circulation path, it is reliably detected by the gas detection means.

When the gas detecting means detects a gas leak, it is preferable to stop the operation of the substrate processing apparatus.

[0011] Further, a pump operation detecting means for detecting an abnormal operation of the pump is further provided, and when the pump operation detecting means detects an abnormal operation of the pump, the operation of the substrate processing apparatus is stopped. It is suitable. Thereby, it is possible to avoid a state in which gas leakage cannot be detected due to the stoppage of the pump.

Further, the higher the concentration of the processing gas in the air taken out, the better, the better.
A position near the processing chamber in the air circulation path and downstream of the processing chamber is preferable.

When an exhaust duct for guiding air leaking from the air circulation path to the outside environment is provided, it is effective to arrange the gas detecting means in the exhaust duct. With such an arrangement, even if a situation in which air is not sent by the pump occurs, the same gas leak detection as in the related art can be performed.

The present invention is further directed to a gas leak detection method for detecting a leak of a processing gas from a processing chamber in a high-temperature processing apparatus, and the method is directed to suctioning cooling air from a air circulation path by a pump. Then, the air sucked and discharged by the pump is blown to the detecting section of the gas detecting means. The function and effect of such a method are as described above, and achieve rapid and reliable gas leak detection.

[0015]

DETAILED DESCRIPTION OF THE INVENTION Preferred embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic explanatory view showing an epitaxial growth apparatus to which the present invention is applied. The illustrated epitaxial growth apparatus 10 is for forming an epitaxial layer of silicon on a semiconductor wafer as a substrate to be processed, and has a processing chamber 12 made of quartz glass. In the processing chamber 12, a susceptor (not shown) that horizontally supports the semiconductor wafer on its upper surface is provided. A plurality of halogen lamps 14 are provided above and below the processing chamber 12 as heating means for heating the inside of the processing chamber 12 and thus heating the wafer W.
Is arranged. A gas supply port (not shown) for supplying a processing gas is provided at a part of a side portion of the processing chamber 12, and an exhaust port (not shown) is provided at a position facing the gas supply port. I have. Since the gas supply port and the exhaust port sandwich the susceptor and are located at substantially the same height as the upper surface of the susceptor, the processing gas supplied from the gas supply port into the processing chamber is layered along the surface of the semiconductor wafer on the susceptor. It will flow in a flowing state.

The processing chamber 12 of the epitaxial growth apparatus 10 has an enclosure 1 called a shroud or the like.
It is surrounded by 6. The surrounding body 16 functions as a heat insulator that suppresses transmission of heat of the halogen lamp 14 to the outside. A space formed between the enclosure 16 and the processing chamber 12 is partitioned by a partition plate 18 so as to form a circulation path of cooling air. In the illustrated embodiment, a partition plate 18 is provided so that cooling air flows from the upper space and the lower space in the enclosure 16 toward the processing chamber 12 and flows out through the side surface of the processing chamber 12.

Two air circulation ducts 20 and 22 are connected to the upper surface of the enclosure 16. One duct 20
One end is connected to a discharge port of the air circulation blower 24, and the other end is connected to a position where cooling air can be sent into the upper space and the lower space of the enclosure 16. The other duct 22 flows along the periphery of the processing chamber 12 and is connected to a position where air that has taken heat and whose temperature has risen flows out. The other end of the duct 22 is connected to a heat exchanger 26 to cool the air heated around the processing chamber 12 so that it can be used again as cooling air. The air that has passed through the heat exchanger 26 is mixed with external air in the mixing chamber 28 and further cooled, and then flows into the air inlet of the blower 24. in this way,
Space between processing chamber 12 and enclosure 16, duct 2
0, 22, the heat exchanger 26, the mixing chamber 28, and the blower 24 constitute an air circulation path for circulating cooling air.

The air circulation path is not closed, as can be understood from the intake of air from the outside in the mixing chamber 28. In particular, the cooling air leaks from the blower 24. For this reason, an exhaust duct 30 for taking in the leaked cooling air and guiding it to the outside of the semiconductor manufacturing factory is provided near the blower 24. A gas detector 32 for detecting a processing gas is disposed in the exhaust duct 30, particularly in a position near the blower 24.

Since the epitaxial growth apparatus 10 in the illustrated embodiment is for forming an epitaxial layer of silicon as described above, trichlorosilane (S
A mixed gas containing an iHCl ₃ ) gas, a dichlorosilane (SiH ₂ Cl ₂ ) gas or the like as a main component, and a hydrogen gas as a carrier gas is used as a processing gas. Therefore, it is effective to detect a large amount of hydrogen gas contained in the processing gas. Therefore, in the illustrated embodiment, a diffusion-type hydrogen gas detector 32 is used as the gas detector. The reason why the diffusion type is used is that highly accurate gas concentration detection is possible, but other types of detectors may be used.

The output signal of the hydrogen gas detector 32 corresponds to the hydrogen gas concentration, and is input to the control device 34 which controls the entire operation of the epitaxial growth apparatus 10. The control device 34 always calculates a signal from the gas detector 32 and determines whether or not hydrogen gas is present in the air at an allowable value or more, that is, determines whether or not the processing gas is leaked.

Further, in the illustrated embodiment, an air outlet 36 is formed at an intermediate portion of the duct 22, and one end of an air outlet pipe 38 is connected to the air outlet 36. The other end of the air outlet tube 38 is connected to a suction port of a suitable pump 40. An air feed pipe 42 extends from the discharge port of the pump 40, and the tip of the air feed pipe 42 is arranged near the hydrogen gas detector 32, and the air sent from the pump 40 is detected by the hydrogen gas detector 32. It is designed to be sprayed on the part.

The air outlet 36 is located downstream of the processing chamber 12 in the circulating flow of cooling air,
Although a portion as close to the processing chamber 12 as possible is preferable,
Since the temperature of the air is too high in a portion that is excessively close to the processing chamber 12, the temperature is actually determined in consideration of the temperature of the extracted air. When high-temperature air is taken out, fins for air cooling may be provided on the surfaces of the air take-out pipe 38 and the air feed pipe 42 so as to sufficiently cool the hydrogen gas detector 32 before the air reaches the hydrogen gas detector 32. .

Electric motor 4 for driving pump 40
4 is provided with an overcurrent detector 46, which can detect whether or not the current flowing through the electric motor 44 is equal to or larger than an allowable value. When the electric motor 44 or the pump 40 is stopped due to some operation abnormality, an overcurrent flows through the electric motor 44. Therefore, the operation abnormality of the pump 40 is detected by detecting the overcurrent by the overcurrent detector 46. can do. The output signal of the overcurrent detector 46 is also input to the control device 34.

In FIG. 1, reference numerals indicate a support frame 48 for supporting the epitaxial growth apparatus 10 and other accessories.

When the epitaxial growth apparatus 10 having the above-described configuration is started, the halogen lamp 14 is turned on, the processing gas is introduced into the processing chamber 12, and a silicon epitaxial layer is formed on the semiconductor wafer supported by the susceptor. Is done. During this time, the blower 24 is driven and fresh air is supplied to the air holes 5 in the mixing chamber 28.
Cooling air circulates through the air circulation path including the duct 20, the internal space of the enclosure 16, the duct 22, the heat exchanger 26, and the mixing chamber 28 while being taken in from zero. As a result, the processing chamber 12 heated to a high temperature
From the surface of the epitaxial growth apparatus 10 and prevent adverse thermal effects on components and accessories of the epitaxial growth apparatus 10.

A part of the air passing through the periphery of the processing chamber 12 and flowing through the damper 22 is sucked by a pump 40 from an air outlet 36 at an intermediate portion of the duct 22.
The air sucked by the pump 40 is directly blown to the detection part of the hydrogen gas detector 32 through the air feed pipe 42. In the control device 34, the hydrogen gas detector 32
The concentration of hydrogen in the air in the duct 22 is determined based on the signal from Here, if the processing gas leaks from the processing chamber 12, the concentration of hydrogen in the air taken out of the duct 22 increases.
Determines that the processing gas has leaked from the processing chamber 12 or the like when the hydrogen concentration obtained from the signal from the hydrogen gas detector 32 exceeds a predetermined allowable value.

The air blown to the hydrogen gas detector 32 through the air feed pipe 42 is supplied to the epitaxial growth apparatus 1.
0, because it is not mixed with external air,
That is, the hydrogen concentration is as high as the air in the duct 22. Therefore, the leak gas detecting means including the hydrogen gas detector 32 and the control device 34 can reliably and quickly detect the leak of the processing gas. Further, since the concentration of the leaked gas is high, the fluctuation amount of the signal output from the diffusion-type hydrogen gas detector 32 is large, and it is possible to clearly determine whether or not the allowable value has been exceeded. Even a gas detector having a low capability can be sufficiently handled.

When the control device 34 determines that the processing gas has leaked, it issues an alarm by an alarm 52 to notify the operator of the gas leak. At the same time, the operation of the epitaxial growth apparatus 10 is urgently stopped, for example, by stopping the supply of the processing gas, thereby preventing further gas leakage.

Further, an abnormality occurs in the pump 40 and the like, and the air containing the processing gas is supplied to the air extraction pipe 38 and the air feed pipe 4.
In the event that it is not possible to supply the hydrogen gas to the hydrogen gas detector 32 through the nozzle 2, the gas exposed from around the blower 24 is also sent to the hydrogen gas detector 32, so that the leakage of the processing gas can be detected in the same manner as in the prior art. .

However, in this embodiment, the pump 4
Since an abnormality such as 0 can be detected by the overcurrent detector 46, when the control device 34 receives the abnormality detection signal from the overcurrent detector 46, the control device 34 determines that high-precision gas leakage cannot be detected and determines that the epitaxial growth device 10 Has been shut down to address gas leaks to a higher degree.

FIG. 2 is a graph showing the results of an experiment comparing the ability to detect a process gas leak between the epitaxial growth apparatus 10 according to the present invention and a conventional configuration. In the experiment according to FIG. 2, the epitaxial growth apparatus 10 shown in FIG. 1 and a conventional apparatus in which the pump 40 and the pipes 38 and 42 were removed from the configuration of FIG. 1 were used. Further, the same silicon epitaxial growth process was performed, and after a lapse of a predetermined time from the start of the process, the processing gas was leaked outside from the exhaust port of the processing chamber 12 for 3 seconds. As can be seen from FIG. 2 showing the results of this experiment, in the configuration of the present invention, the value of the hydrogen gas concentration obtained by the hydrogen gas detector 32 sharply and rapidly increases in a short time from the start of the processing gas leakage. . On the other hand, in the conventional configuration, the hydrogen gas concentration increases relatively slowly, and the peak concentration is lower than that of the present invention.
Therefore, according to the configuration of the present invention, it was found that the presence or absence of the leakage of the processing gas can be determined clearly and quickly. Note that the reason why the gas concentration shows a constant height for a while even after the process gas leakage is stopped is that part of the leaked gas continues to circulate in the air circulation path.

Although the preferred embodiments of the present invention have been described in detail, it goes without saying that the present invention is not limited to the above embodiments. For example, the above embodiment relates to an epitaxial growth apparatus, but the present invention is applicable to various substrate processing apparatuses such as a thermal CVD apparatus.
In other substrate processing apparatuses, since the type of the processing gas is different, a detector corresponding to the component of the processing gas is appropriately selected as the gas detecting means.

Some gas detectors can emit a leak signal when a gas leaks. In such a case, the control device does not need to judge the gas leak.

Further, various means for detecting an abnormal operation of the pump other than the overcurrent detector, such as a means for monitoring the rotation of the pump, can be considered.

[0036]

As described above, according to the present invention, in a substrate processing apparatus for performing a heat treatment on a substrate in a processing chamber, if leakage of a processing gas should occur, it can be quickly and reliably performed. It becomes possible to detect.

Further, since the reliability of gas leak detection is greatly improved, it is possible to use an inexpensive gas detector having a lower detection capability than in the past, thereby reducing the cost of equipment and the cost of products. It can also contribute to down.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing an epitaxial growth apparatus configured according to the present invention.

FIG. 2 is a graph showing the gas leak detection capability of the present invention in comparison with a conventional configuration.

[Explanation of symbols]

10 ... Epitaxial growth device (substrate processing device), 12
... processing chamber, 14 ... halogen lamp, 16 ... enclosure, 20,22 ... duct, 24 ... blower, 32 ... gas detector (gas detecting means), 34 ... control device (gas detecting means, first and second) Stopping means), 38 ... air extraction pipe,
Reference numeral 40: pump, 42: air feed pipe, 46: overcurrent detector (pump operation detecting means).

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akihiko Abe 14-3 Shinzumi, Narita-shi, Chiba Nogehira Industrial Park In Applied Materials Japan Co., Ltd. (72) Inventor Yoji Takagi 14-3 Shinizumi, Noizumi, Narita-shi, Chiba Applied Materials Japan Co., Ltd. (72) Inventor Naoki Oka 14-3 Shinsen, Narita-shi, Chiba Prefecture Nogeira Industrial Park Applied Materials Japan Inc. AA17 BA29 BB01 CA04 EA12 FA10 HA15 KA26 KA39 5F045 AA01 AB02 AC05 BB08 BB20 EF20 EG02 EG06 EJ04 EJ10 EK11

Claims (7)

[Claims] 1. A processing chamber in which a processing gas is introduced and heated inside to process a substrate to be processed disposed therein, an enclosure surrounding the processing chamber, the enclosure and the processing. Including a space between the chamber as a part of the flow path, an air circulation path for circulating cooling air, a pump for taking out cooling air from the air circulation path, A substrate processing apparatus, comprising: gas detection means for detecting the processing gas, wherein the gas is discharged from the pump and sent to a detection unit. 2. The substrate processing apparatus according to claim 1, further comprising: first stopping means for stopping the operation of the substrate processing apparatus when the gas detecting means detects a processing gas. 3. The substrate processing apparatus according to claim 1, further comprising a pump operation detecting unit that detects an abnormal operation of the pump. 4. The substrate processing apparatus according to claim 3, further comprising second stopping means for stopping the operation of the substrate processing apparatus when the pump operation detecting means detects an abnormal operation of the pump. 5. The cooling device according to claim 1, wherein the pump is configured to take out cooling air from a position near the processing chamber in the air circulation path and downstream from the processing chamber. The substrate processing apparatus according to claim 1. 6. The exhaust gas duct according to claim 1, further comprising an exhaust duct that guides air leaked from the air circulation path to an external environment, wherein the gas detection unit is disposed in the exhaust duct. Substrate processing equipment. 7. A processing chamber into which a processing gas is introduced and the inside of which is heated to process a substrate to be processed disposed therein, an enclosure surrounding the processing chamber, the processing chamber and the enclosure. An air circulation path for circulating cooling air, which includes a space between the body as a part of the flow path, and a gas detector for detecting the processing gas, which is disposed outside the air circulation path. Means for detecting a leakage of a processing gas from the processing chamber, wherein a step of sucking cooling air from the air circulation path with a pump; and Sending the air sucked and discharged by the gas detection means to the detection unit of the gas detection means.