Heat treatment equipment

Abstract

A chamber that heats semiconductor wafers by irradiating them with light is connected to a combustible gas supply source via a combustible gas supply pipe. The combustible gas supply pipe is equipped with an electrical flow controller and other components that adjust the flow rate of the combustible gas. The portion of the combustible gas supply pipe containing the electrical flow controller and other components that could become a source of ignition is surrounded by an inner frame. Nitrogen, a non-combustible gas, is supplied to the inner space within the inner frame. By supplying non-combustible gas to the inner space and exhausting the gas remaining in the inner space, the oxygen concentration in the inner space is reduced to below the explosion limit, thereby preventing fires and explosions caused by the combustible gas.

Description

Technical Field

[0001] The present invention relates to a heat treatment apparatus that heats a thin plate-shaped precision electronic substrate (hereinafter referred to as a "substrate") such as a semiconductor wafer by irradiating the substrate with light. Background Art

[0002] As an apparatus for manufacturing semiconductor devices, heat treatment apparatuses that irradiate semiconductor wafers with light to heat the semiconductor wafers are widely used. For example, Patent Document 1 discloses a heat treatment apparatus that irradiates a semiconductor wafer having a high-dielectric constant film (high-k film) formed thereon with flash light from a flash lamp, instantaneously heating the surface of the semiconductor wafer and thereby performing post-film heat treatment of the high-dielectric constant film.

[0003] In such heat treatment apparatuses, combustible gases such as hydrogen (H2) or ammonia (NH3) are often used for heat treatment. In the heat treatment apparatus disclosed in Patent Document 1, a high dielectric constant film is nitrided by heating a semiconductor wafer in an ammonia atmosphere.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-045982 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] When using flammable gases, there is a strong demand for countermeasures to prevent fires and explosions caused by these gases. The flow rate and pressure of these flammable gases are often controlled through electrical systems, which have a high potential to become ignition sources. Therefore, the use of intrinsically safe and explosion-proof shielded relays is typically required. However, intrinsically safe and explosion-proof shielded relays not only have limited controllable current capacity, but also are bulky and expensive, limiting their scope of application.

[0009] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a heat treatment apparatus capable of preventing fire and explosion of combustible gas with a simple structure.

[0010] Means used to solve problems

[0011] In order to solve the above-mentioned problems, a first type of heat treatment device of the present invention heats a substrate by irradiating light onto the substrate, wherein the device comprises: a chamber for accommodating a substrate; a lamp for irradiating light onto the substrate accommodated in the chamber; a first gas supply pipe for supplying combustible gas from a first gas supply source to the chamber; an electrical flow adjustment unit installed on the first gas supply pipe for adjusting the supply flow rate of the combustible gas; a first frame body for surrounding a portion of the first gas supply pipe at least including the flow adjustment unit; a second frame body for further surrounding the first frame body; a second gas supply pipe for supplying non-combustible gas from a second gas supply source to a first space inside the first frame body; and a gas exhaust port provided on the first frame body for discharging the gas retained in the first space to a second space formed between the first frame body and the second frame body.

[0012] In addition, a second aspect is the heat treatment apparatus according to the first aspect, further comprising an exhaust portion configured to exhaust gas retained in the second space.

[0013] In addition, a third aspect is the heat treatment apparatus according to the second aspect, further comprising a suction port provided in the second housing for taking air into the second space.

[0014] In a fourth aspect, in the heat treatment apparatus of any one of the first to third aspects, the heat treatment apparatus further includes a first differential pressure gauge that measures a pressure difference between the pressure of the first space and the pressure of the second space.

[0015] Moreover, a fifth aspect is the heat treatment apparatus according to the fourth aspect, further comprising a second differential pressure gauge configured to measure a pressure difference between the pressure of the second space and atmospheric pressure.

[0016] In addition, the sixth method is that in the heat treatment device of the fifth method, the heat treatment device further includes a control unit, and when the pressure of the second space is higher than the pressure of the first space or the pressure of the second space is higher than the atmospheric pressure, the control unit stops supplying the combustible gas from the first gas supply source to the chamber.

[0017] Effects of the Invention

[0018] According to the heat treatment apparatus of the first to sixth aspects, since the first housing surrounds the portion of the first gas supply pipe containing at least the electrical flow rate adjustment unit, non-combustible gas is supplied to the first space within the first housing and the gas retained in the first space is discharged. This reduces the oxygen concentration in the first space, thereby preventing fires and explosions caused by combustible gas with a simple structure. Furthermore, since the non-combustible gas is discharged into the second space within the second housing, safety is ensured.

[0019] In particular, according to the heat treatment device of the sixth embodiment, when the pressure of the second space is higher than the pressure of the first space or the pressure of the second space is higher than the atmospheric pressure, the supply of combustible gas from the first gas supply source to the chamber is stopped, thereby reliably preventing fire and explosion of combustible gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a diagram showing the main structure of the heat treatment apparatus of the present invention.

[0021] Figure 2 It is a diagram showing the structure of the explosion-proof mechanism. DETAILED DESCRIPTION

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0023] Figure 1 It is a diagram showing the main structure of the heat treatment apparatus 1 of the present invention. Figure 1 The heat treatment apparatus 1 is a flash lamp annealing apparatus that heats a semiconductor wafer W in a circular plate shape as a substrate by flash irradiating the semiconductor wafer W. The size of the semiconductor wafer W to be processed is not particularly limited, for example, or In addition, Figure 1 In the following drawings, the size or number of each component is exaggerated or simplified as necessary to facilitate understanding.

[0024] Heat treatment apparatus 1 includes: a chamber 10 that accommodates a semiconductor wafer W; a flash irradiation unit 60 that irradiates the semiconductor wafer W in chamber 10 with flash light; a halogen irradiation unit 70 that irradiates the semiconductor wafer W with halogen light; a gas supply unit 20 that supplies a process gas into chamber 10; and an exhaust unit 80 that exhausts gas from chamber 10. Heat treatment apparatus 1 also includes a control unit 90 that controls these components to execute the flash irradiation.

[0025] The chamber 10 accommodates a semiconductor wafer W to be processed, and heat treatment of the semiconductor wafer W is performed within the chamber 10. An upper chamber window 11 is installed at the upper opening of the chamber 10 to seal it, and a lower chamber window 12 is installed at the lower opening of the chamber 10 to seal it. The space enclosed by the side walls of the chamber 10, the upper chamber window 11, and the lower chamber window 12 is defined as a heat treatment space 15. The upper chamber window 11, which constitutes the top of the chamber 10, is a plate-shaped member formed of quartz and functions as a quartz window that allows the flash light emitted from the flash irradiation unit 60 to pass into the heat treatment space 15. In addition, the lower chamber window 12, which constitutes the bottom of the chamber 10, is also a plate-shaped member formed of quartz and functions as a quartz window that allows the light from the halogen irradiation unit 70 to pass into the heat treatment space 15.

[0026] A transfer opening 14 is provided on a side wall of the chamber 10 for loading and unloading semiconductor wafers W. The transfer opening 14 can be opened and closed by a gate valve (not shown). When the transfer opening 14 is open, a transfer robot (not shown) can load and unload semiconductor wafers W into and out of the chamber 10. When the transfer opening 14 is closed, the heat treatment space 15 becomes a sealed space, cut off from external ventilation.

[0027] A susceptor 18 is provided inside the chamber 10 for holding a semiconductor wafer W. The susceptor 18 is a disk-shaped member made of quartz. The diameter of the susceptor 18 is slightly larger than the diameter of the semiconductor wafer W. The susceptor 18 holds the semiconductor wafer W in a horizontal position (a position in which the normal direction of the main surface is aligned with the vertical direction) within the chamber 10.

[0028] The flash irradiation unit 60 is located above the chamber 10. It comprises a light source composed of multiple flash lamps FL and a reflector 62 positioned above the light source. The flash irradiation unit 60 irradiates a flash of light from the flash lamps FL to the semiconductor wafer W held by the susceptor 18 within the chamber 10 through the upper chamber window 11 made of quartz.

[0029] The flash lamps FL are long cylindrical rod-shaped lamps arranged in a plane with their longitudinal directions parallel to each other along the main surface (i.e., in the horizontal direction) of the semiconductor wafer W held by the base 18. Therefore, the plane formed by the arrangement of the flash lamps FL is also a horizontal plane.

[0030] The flashlamp FL consists of a cylindrical glass tube (discharge tube) filled with xenon gas. Its ends are equipped with an anode and cathode connected to a capacitor, and a trigger electrode is attached to the outer circumference of the glass tube. Because xenon gas is an electrical insulator, even if charge accumulates in the capacitor, no electricity flows through the glass tube under normal conditions. However, when a high voltage is applied to the trigger electrode, breaking the insulation, the electricity stored in the capacitor instantly flows through the glass tube, exciting xenon atoms or molecules at this time and emitting light. Because the electrostatic energy pre-stored in the capacitor is converted into extremely short light pulses, lasting from 0.1 to 100 milliseconds, the flashlamp FL is capable of emitting extremely intense light compared to continuously lit light sources such as halogen lamps HL. Specifically, the flashlamp FL is a pulsed light lamp that emits light instantaneously, for a very short period of less than a second. Furthermore, the flashlamp FL's light emission duration can be adjusted by adjusting the coil constant of the lamp power supply that powers the flashlamp FL.

[0031] Reflector 62 is positioned above the flash lamps FL to cover the entire flash tubes FL. The reflector 62's primary function is to reflect the flash light emitted from the flash lamps FL toward the heat treatment chamber 15. Reflector 62 is formed from an aluminum alloy plate, and its surface (the surface facing the flash lamps FL) has been roughened by sandblasting.

[0032] The halogen irradiation unit 70 is provided below the chamber 10 and houses a plurality of halogen lamps HL. The halogen irradiation unit 70 heats the semiconductor wafer W by irradiating light from the plurality of halogen lamps HL into the heat treatment space 15 from below the chamber 10 through the lower chamber window 12 .

[0033] The multiple halogen lamps HL are rod-shaped lamps, each having a long cylindrical shape. They are arranged in a plane with their respective lengths parallel to the main surface of the semiconductor wafer W held by the base 18. Therefore, the plane formed by the arrangement of the halogen lamps HL is also a horizontal plane. Alternatively, the multiple halogen lamps HL can be arranged in a grid with two upper and lower sections.

[0034] Each halogen lamp HL is a filament-type light source. By applying electricity to a filament inside a glass tube, the filament becomes incandescent and emits light. Inside the glass tube, a gas containing a trace amount of halogen elements (iodine, bromine, etc.) introduced into an inert gas such as nitrogen or argon is sealed. The introduction of the halogen element prevents filament breakage and allows the filament temperature to be set to a high temperature. Therefore, compared to conventional incandescent bulbs, halogen lamps HL have a longer service life and are capable of continuously emitting strong light. In other words, halogen lamps HL are continuously lit lamps that emit light for at least one second.

[0035] The exhaust section 80 includes an exhaust device 81 and an exhaust valve 82, and the atmosphere in the chamber 10 is exhausted by opening the exhaust valve 82. As the exhaust device 81, a vacuum pump or exhaust equipment of a factory where the heat treatment apparatus 1 is installed can be used. When a vacuum pump is used as the exhaust device 81, the atmosphere in the heat treatment space 15, which is a closed space, is exhausted without any gas supply from the gas supply section 20, and the pressure in the chamber 10 can be reduced to a vacuum environment. In addition, even when a vacuum pump is not used as the exhaust device 81, the pressure in the chamber 10 can be reduced to a pressure lower than atmospheric pressure by exhausting the atmosphere without supplying gas from the gas supply section 20.

[0036] The gas supply unit 20 includes a combustible gas supply source (first gas supply source) 21 , a non-combustible gas supply source (second gas supply source) 22 , and an explosion-proof mechanism 30 . Figure 2 1 is a diagram showing the structure of the explosion-proof mechanism 30. The explosion-proof mechanism 30 includes an inner housing (first housing) 41 and an outer housing (second housing) 46.

[0037] The combustible gas supply source 21 and the chamber 10 are connected to each other via a combustible gas supply pipe (first gas supply pipe) 31. Specifically, the top end of the combustible gas supply pipe 31 is connected to the chamber 10, and the base end thereof is connected to the combustible gas supply source 21. Combustible gas delivered from the combustible gas supply source 21 is supplied to the chamber 10 via the combustible gas supply pipe 31. As the combustible gas supplied from the combustible gas supply source 21, for example, ammonia (NH3), hydrogen (H2), or the like (ammonia in this embodiment) is used.

[0038] Along the combustible gas supply pipe 31, in order from closest to the chamber 10, are installed an electrical flowmeter 33, an air valve 34, an electrical flow controller 35, an electrical pressure sensor 36, a check valve 37, and a manual valve 38. The electrical flowmeter 33 measures the flow rate of combustible gas flowing through the combustible gas supply pipe 31. The air valve 34 opens and closes the flow path of the combustible gas supply pipe 31 under the control of the control unit 90. The electrical flow controller 35 controls the flow rate of combustible gas flowing through the combustible gas supply pipe 31 based on instructions from the control unit 90. In other words, the electrical flow controller 35 is a flow regulator that adjusts the supply flow rate of combustible gas. The electrical pressure sensor 36 measures the pressure within the combustible gas supply pipe 31. The check valve 37 prevents backflow of combustible gas within the combustible gas supply pipe 31. The manual valve 38 is a valve that is manually opened and closed. The combustible gas supply pipe 31, where these multiple components are attached, is assembled using joints. Among these components, the electric flowmeter 33, the electric flow controller 35, and the electric pressure sensor 36 operate electrically and could become a source of ignition if sparks are generated due to a short circuit or other reasons.

[0039] The inner frame 41 is provided to surround the portion of the combustible gas supply pipe 31 including at least the electric flow meter 33, the electric flow controller 35, and the electric pressure sensor 36 operated by electricity. Figure 2 As shown, in this embodiment, the electric flow meter 33, the electric flow controller 35, the electric pressure sensor 36, and the air valve 34 are arranged in the inner frame 41. In addition, the combustible gas supply pipe 31 is provided so as to penetrate the inner frame 41.

[0040] The inner frame 41 is further surrounded by the outer frame 46. The check valve 37 and the manual valve 38 are arranged between the inner frame 41 and the outer frame 46.

[0041] In addition, the incombustible gas supply source 22 and the inner frame 41 are connected by an incombustible gas supply pipe (second gas supply pipe) 32. A valve 39 is installed in the middle of the path of the incombustible gas supply pipe 32. The setting position of the valve 39 in the incombustible gas supply pipe 32 can be an appropriate position. The valve 39 opens and closes the flow path of the incombustible gas supply pipe 32 under the control of the control unit 90. When the valve 39 is opened, the incombustible gas is supplied from the incombustible gas supply source 22 to the inner space (first space) 43 inside the inner frame 41 through the incombustible gas supply pipe 32. As the incombustible gas supplied from the incombustible gas supply source 22, for example, nitrogen (N2), argon (Ar), etc. (nitrogen in this embodiment) is used.

[0042] The inner frame 41 is provided with a gas outlet 44. The gas outlet 44 connects an exhaust space (second space) 48 formed between the inner frame 41 and the outer frame 46 with the inner space 43 within the inner frame 41. When non-combustible gas is supplied from the non-combustible gas supply source 22 to the inner space 43, causing the pressure of the inner space 43 to increase, the gas outlet 44 discharges the gas retained in the inner space 43 to the exhaust space 48.

[0043] An exhaust port 55 is provided on the outer frame 46. The exhaust port 55 is connected to the exhaust device 56. In addition, an exhaust damper 57 is provided on the exhaust port 55. The exhaust damper 57 is set to an appropriate opening by the control of the control unit 90. By setting the exhaust damper 57 to an appropriate opening while operating the exhaust device 56, the ambient gas in the exhaust space 48 is discharged from the exhaust port 55. The exhaust flow rate from the exhaust port 55 is adjusted by the opening of the exhaust damper 57. That is, the exhaust port 55, the exhaust device 56 and the exhaust damper 57 constitute an exhaust section that discharges the gas retained in the exhaust space 48. In addition, the exhaust device 56 can also be the same as the exhaust device 81 of the chamber 10.

[0044] The outer frame 46 is provided with an air inlet 49 . The air inlet 49 is an opening for taking air from the atmosphere outside the outer frame 46 into the exhaust space 48 .

[0045] The explosion-proof mechanism 30 is also equipped with a micro differential pressure gauge (first differential pressure gauge) 51 and a micro differential pressure gauge (second differential pressure gauge) 52. The micro differential pressure gauge 51 measures the pressure difference between the pressure in the inner space 43 and the pressure in the exhaust space 48. Meanwhile, the micro differential pressure gauge 52 measures the pressure difference between the pressure in the exhaust space 48 and atmospheric pressure. The measurement results of the micro differential pressure gauges 51 and 52 are transmitted to the control unit 90.

[0046] The control unit 90 controls the various operating mechanisms provided in the heat treatment apparatus 1. The hardware structure of the control unit 90 is similar to that of a typical computer. Specifically, the control unit 90 includes a CPU (a circuit that performs various calculations), a ROM (read-only memory) that stores basic programs, a RAM (random access memory) that stores various information, and a magnetic disk pre-stored with control application programs and data. The processing in the heat treatment apparatus 1 is performed by the CPU of the control unit 90 executing a predetermined processing program.

[0047] Next, a description will be given of the processing operation in the heat treatment apparatus 1. First, a brief description will be given of the processing of the semiconductor wafer W in the heat treatment apparatus 1, and then an explanation will be given of explosion prevention when supplying a combustible gas.

[0048] A semiconductor wafer W to be processed is loaded into the chamber 10 through the transfer opening 14 and held by the susceptor 18. After the transfer opening 14 is closed, ammonia gas, a combustible gas, is supplied from the gas supply unit 20 into the chamber 10, thereby forming a gas atmosphere containing ammonia gas in the heat treatment space 15.

[0049] After a gas atmosphere containing ammonia is created in the heat treatment chamber 15, the semiconductor wafer W is held by the susceptor 18. The halogen lamp HL of the halogen irradiation unit 70 is then illuminated to initiate preliminary heating (auxiliary heating) of the semiconductor wafer W. Light emitted from the halogen lamp HL passes through the lower chamber window 12, formed of quartz, and the susceptor 18, irradiating the lower surface of the semiconductor wafer W. Irradiation by the light from the halogen lamp HL causes preliminary heating of the semiconductor wafer W, raising its temperature. After the temperature of the semiconductor wafer W rises and reaches a predetermined preliminary heating temperature, it is maintained at this temperature for approximately several seconds.

[0050] When the temperature of the semiconductor wafer W reaches the preheating temperature and a predetermined time has elapsed, the flash lamp FL of the flash irradiation unit 60 flash-irradiates the surface of the semiconductor wafer W held by the susceptor 18. The flash irradiated by the flash lamp FL is a strong flash of light, obtained by converting the electrostatic energy previously stored in the capacitor into an extremely short light pulse. The flash irradiation duration is approximately 0.1 milliseconds to 100 milliseconds. By irradiating the semiconductor wafer W with this extremely short and intense flash of light, the surface temperature of the semiconductor wafer W instantly rises to the processing temperature and then rapidly drops. By instantaneously heating the surface of the semiconductor wafer W to the processing temperature in a gas atmosphere containing ammonia, the film (e.g., a high-dielectric-constant film) formed on the surface of the semiconductor wafer W is nitrided.

[0051] After the flash heating process is completed, the halogen lamp HL is turned off after a predetermined period of time. This causes the temperature of the semiconductor wafer W to drop from the preheating temperature. Furthermore, the ammonia-containing atmosphere within the chamber 10 is exhausted from the chamber 10 via the exhaust unit 80. After the temperature of the semiconductor wafer W drops below a predetermined temperature, the heat-treated semiconductor wafer W is unloaded from the transfer opening 14, and the heating process is terminated.

[0052] When ammonia gas, serving as a combustible gas, is supplied from the gas supply unit 20 to the chamber 10, the manual valve 38 is opened, and the air valve 34 is opened under the control of the control unit 90. As a result, ammonia gas is supplied from the combustible gas supply source 21 to the chamber 10 through the combustible gas supply pipe 31. The flow rate of ammonia gas supplied to the chamber 10 through the combustible gas supply pipe 31 is adjusted by an electrical flow controller 35. The flow rate of ammonia gas passing through the combustible gas supply pipe 31 is measured by an electrical flow meter 33, and the pressure within the combustible gas supply pipe 31 is measured by an electrical pressure sensor 36.

[0053] However, for a flammable gas like ammonia to cause a fire or explosion, three factors are required: the presence of the flammable gas itself, an ignition source, and oxygen, a combustion-supporting gas. The area where the electrical flow controller 35 and other components are installed also has piping joints, through which flammable gas could leak. Furthermore, the electrical flow controller 35 and other components, which operate using electricity, could also become an ignition source. Therefore, especially when the electrical flowmeter 33, electrical flow controller 35, and electrical pressure sensor 36 are exposed to an atmosphere containing oxygen, all three factors necessary for a fire or explosion are present, potentially leading to a fire or explosion.

[0054] Therefore, in this embodiment, the occurrence of fire and explosion is prevented as follows. First, the portion of the combustible gas supply pipe 31 that includes the electrical flowmeter 33, electrical flow controller 35, and electrical pressure sensor 36, which could become a source of ignition, is surrounded by an inner frame 41. Nitrogen, serving as an incombustible gas, is then supplied from the incombustible gas supply source 22 via the incombustible gas supply pipe 32 to the inner space 43 within the inner frame 41. As the incombustible gas is supplied to the inner space 43, the gas remaining in the inner space 43 is discharged from the gas outlet 44 into the exhaust space 48. This replaces the atmosphere in the inner space 43 with the incombustible gas, reducing the oxygen concentration in the inner space 43.

[0055] Furthermore, the differential pressure between the pressure in the inner space 43 and the pressure in the exhaust space 48 is measured by a micro-differential pressure gauge 51. When non-combustible gas is supplied to the inner space 43 and the gas in the inner space 43 is discharged from the gas outlet 44, if the pressure in the inner space 43 is higher than the pressure in the exhaust space 48, that is, if the inner space 43 is at a positive pressure relative to the exhaust space 48, then the oxygen concentration in the inner space 43 can be considered to have dropped to 3% or less. If the oxygen concentration in the inner space 43 is 3% or less, even if flammable gas were to leak from the inner space 43, the combustion-supporting gas, one of the three elements required for a fire or explosion, would be insufficient, thus preventing a fire or explosion caused by the flammable gas.

[0056] The nitrogen gas supplied to the inner space 43 as an incombustible gas is discharged from the gas outlet 44. When the nitrogen gas is discharged directly into the atmosphere from the gas outlet 44, a high-concentration nitrogen environment area (i.e., an oxygen-deficient area) is formed in the operating space of the operator of the heat treatment device 1, which is therefore dangerous. Therefore, in the present embodiment, the inner frame 41 is further surrounded by the outer frame 46, thereby forming an exhaust space 48 between the inner frame 41 and the outer frame 46. The nitrogen gas discharged from the gas outlet 44 is discharged into the exhaust space 48. Then, the nitrogen gas flowing into the exhaust space 48 is discharged from the exhaust port 55 through the exhaust device 56. In addition, since there is no element that may become a source of ignition in the exhaust space 48, there is no need to worry about fire or explosion in the exhaust space 48.

[0057] Furthermore, the differential pressure between the pressure in the exhaust space 48 and atmospheric pressure is measured by a micro-differential pressure gauge 52. If the atmospheric pressure is higher than the pressure in the exhaust space 48, that is, if the atmospheric pressure is positive relative to the exhaust space 48, nitrogen gas in the exhaust space 48 can be prevented from flowing back into the atmosphere through the suction port 49. As a result, a high-concentration nitrogen atmosphere is prevented from forming in the operating space of the operator of the heat treatment apparatus 1, thereby ensuring safety.

[0058] The measurement results of the micro-differential pressure gauges 51 and 52 are monitored by the control unit 90. If the pressure of the exhaust space 48 is detected to be higher than the pressure of the inner space 43 based on the measurement results of the micro-differential pressure gauge 51, the control unit 90 closes the air valve 34 and stops the supply of combustible gas from the combustible gas supply source 21 to the chamber 10. This is because if the pressure of the exhaust space 48 is higher than the pressure of the inner space 43, the oxygen concentration in the inner space 43 may become so high that it exceeds the explosion limit, and the possibility of a fire or explosion of the combustible gas cannot be completely eliminated.

[0059] Furthermore, if the pressure of the exhaust space 48 is detected to be above atmospheric pressure based on the measurement results of the micro-differential pressure gauge 52, the control unit 90 closes the air valve 34, thereby stopping the supply of combustible gas from the combustible gas supply source 21 to the chamber 10. At this time, the control unit 90 also closes the valve 39, thereby stopping the supply of nitrogen gas to the inner space 43. This is because, if the pressure of the exhaust space 48 is above atmospheric pressure, the nitrogen gas in the exhaust space 48 may flow back into the atmosphere through the suction port 49, potentially forming a high-concentration nitrogen atmosphere in the operating space of the operator of the heat treatment apparatus 1.

[0060] In this embodiment, the portion of the combustible gas supply pipe 31 that includes the electrical flowmeter 33, electrical flow controller 35, and electrical pressure sensor 36, which could potentially become a source of ignition, is surrounded by an inner frame 41. Furthermore, nitrogen, a non-combustible gas, is supplied to the inner space 43 within the inner frame 41. By supplying non-combustible gas to the inner space 43 and discharging any remaining gas from the gas outlet 44, the oxygen concentration in the inner space 43 is reduced to below the explosion limit. As a result, even if combustible gas leaks from a joint or other portion of the combustible gas supply pipe 31, fires and explosions caused by the combustible gas can be prevented. In other words, a simple structure that supplies non-combustible gas to the frame prevents fires and explosions caused by combustible gas.

[0061] In addition, the inner frame 41 is further surrounded by the outer frame 46, so that the incombustible gas discharged from the inner space 43 into the exhaust space 48 is discharged from the exhaust port 55. As a result, the incombustible gas is not discharged into the atmosphere, thereby ensuring the safety of the operating space for the operator of the heat treatment apparatus 1.

[0062] Furthermore, the differential pressure between the pressure of the inner space 43 and the pressure of the exhaust space 48 is measured by a micro-differential pressure gauge 51, and the differential pressure between the pressure of the exhaust space 48 and atmospheric pressure is measured by a micro-differential pressure gauge 52. The measurement results of the micro-differential pressure gauges 51 and 52 are monitored by the control unit 90. When the pressure of the exhaust space 48 is higher than the pressure of the inner space 43, or when the pressure of the exhaust space 48 is higher than atmospheric pressure, the supply of combustible gas from the combustible gas supply source 21 to the chamber 10 is stopped. This reliably prevents fires and explosions caused by combustible gas.

[0063] While the embodiments of the present invention have been described above, various modifications other than those described above are possible without departing from the spirit of the present invention. For example, in the above embodiment, the electrical flowmeter 33, electrical flow controller 35, and electrical pressure sensor 36 are components that could become ignition sources. However, this is not limiting; other components that could become ignition sources may also be installed in the combustible gas supply pipe 31. In this case, all components that could become ignition sources are surrounded by the inner frame 41.

[0064] In addition, in the above-mentioned embodiment, a filament-type halogen lamp HL is used as a continuous lighting lamp that continuously emits light for more than 1 second to perform preliminary heating of the semiconductor chip W, but this is not limited to this. A discharge-type arc lamp (for example, a xenon arc lamp) can also be used instead of the halogen lamp HL as a continuous lighting lamp for preliminary heating.

[0065] Furthermore, the substrate to be processed by the heat treatment apparatus 1 is not limited to a semiconductor wafer, and may be a glass substrate used for a flat panel display such as a liquid crystal display device or a substrate for a solar cell.

[0066] In the above-described embodiment, the semiconductor wafer W is heated by being irradiated with a flash of light within the chamber 10. However, the present invention is not limited thereto. The semiconductor wafer W accommodated within the chamber 10 may be heated by simply irradiating it with light from the halogen lamp HL. Furthermore, the treatment of the semiconductor wafer W within the chamber 10 is not limited to heat treatment by irradiation with light; any substrate treatment using a combustible gas may be used.

[0067] Industrial Applicability

[0068] The technology involved in the present invention is applicable to a substrate processing technology for performing a predetermined process on a substrate using a combustible gas such as ammonia.

[0069] Description of reference numerals:

[0070] 1: Heat treatment device

[0071] 10: Chamber

[0072] 20: Gas supply unit

[0073] 21: Combustible gas supply source

[0074] 22: Non-combustible gas supply source

[0075] 30: Explosion-proof mechanism

[0076] 31: Combustible gas supply pipe

[0077] 32: Non-combustible gas supply pipe

[0078] 33: Electrical flow meter

[0079] 35: Electrical flow controller

[0080] 36: Electrical pressure sensor

[0081] 41: Inner frame

[0082] 43: Inside Space

[0083] 46: Outer frame

[0084] 48: Exhaust space

[0085] 49: Suction port

[0086] 51, 52: Micro differential pressure gauge

[0087] 55: Exhaust port

[0088] 56: Exhaust

[0089] 57: Exhaust damper

[0090] 60: Flash irradiation part

[0091] 70: Halogen irradiation part

[0092] 90: Control Department

[0093] FL: Flash

[0094] HL: Halogen lamp

Claims

1. A heat treatment apparatus for heating a substrate by irradiating light onto the substrate, wherein: have: a chamber for accommodating a substrate; a lamp for irradiating light toward the substrate housed in the chamber; a first gas supply pipe for supplying combustible gas from a first gas supply source to the chamber; an electrical flow rate adjustment unit installed on the first gas supply pipe to adjust the supply flow rate of the combustible gas; a first frame surrounding a portion of the first gas supply pipe including at least the flow rate adjustment unit; a second frame further surrounding the first frame; a second gas supply pipe for supplying non-combustible gas from a second gas supply source to the first space inside the first housing; and The gas exhaust port is provided on the first frame body and discharges the gas retained in the first space to a second space formed between the first frame body and the second frame body.

2. The heat treatment device according to claim 1, wherein The heat treatment apparatus further includes an exhaust portion that exhausts gas retained in the second space.

3. The heat treatment device according to claim 2, wherein The heat treatment device further includes a suction port provided in the second frame body for taking air into the second space.

4. The heat treatment device according to any one of claims 1 to 3, wherein The heat treatment apparatus further includes a first differential pressure gauge that measures a pressure difference between the pressure in the first space and the pressure in the second space.

5. The heat treatment device according to claim 4, wherein The heat treatment apparatus further includes a second differential pressure gauge configured to measure a pressure difference between the pressure of the second space and atmospheric pressure.

6. The heat treatment device according to claim 5, wherein The heat treatment apparatus further includes a control unit configured to stop supplying the combustible gas from the first gas supply source to the chamber when the pressure of the second space is equal to or higher than the pressure of the first space or when the pressure of the second space is equal to or higher than atmospheric pressure.

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