Heat treatment equipment

Abstract

This invention provides a heat treatment apparatus that reduces the space required for gas supply-related components. In this heat treatment apparatus, a chamber (10) for heating a semiconductor wafer is connected to a combustion-supporting gas line (31), a combustible gas line (41), and an inert gas line (51). Before supplying combustible gas to the chamber (10), nitrogen is introduced from the inert gas line (51) into the combustion-supporting gas line (31) to replace the combustion-supporting gas line (31) with nitrogen. Similarly, before supplying combustion-supporting gas to the chamber (10), nitrogen is introduced from the inert gas line (51) into the combustible gas line (41) to replace the combustible gas line (41) with nitrogen. Since the combustion-supporting gas line (31) and the combustible gas line (41) share a common inert gas line (51), the space required for gas supply-related components can be reduced.

Description

Technical Field

[0001] This invention relates to a heat treatment apparatus for heating a thin, plate-shaped precision electronic substrate (hereinafter referred to as "substrate") such as a semiconductor wafer in an atmosphere of flammable gas or combustion-supporting gas. Background Technology

[0002] As equipment for manufacturing semiconductor devices, heat treatment apparatuses are widely used to heat semiconductor wafers by irradiating them with light. These heat treatment apparatuses perform the heat treatment of semiconductor wafers in various gas atmospheres. For example, a semiconductor wafer with a high-k dielectric film formed on it is nitrided by irradiating it with light in an ammonia atmosphere. Alternatively, a silicon semiconductor wafer is irradiated with light in an oxygen atmosphere to form an oxide film. Furthermore, sometimes oxidation is performed in an oxygen atmosphere followed by nitriding in an ammonia atmosphere, or nitriding is performed in an ammonia atmosphere followed by oxidation in an oxygen atmosphere.

[0003] However, ammonia is a flammable gas, and oxygen is a supporting gas. Therefore, during continuous oxidation and nitriding processes, the mixing of ammonia (a flammable gas) and oxygen (a supporting gas) within the apparatus is dangerous. Thus, for example, Patent Document 1 discloses a technique that installs two valves in the respective gas supply lines for the flammable and supporting gases, supplying an inert gas between them. Furthermore, Patent Document 2 discloses a technique that separately exhausts the residual flammable and supporting gases within the apparatus to prevent them from mixing and reacting. Moreover, Patent Document 3 discloses a technique that, to avoid mixing of the flammable and supporting gases in the exhaust piping, supplies an inert gas to the exhaust piping to dilute the flammable and supporting gases.

[0004] [Existing Technical Documents]

[0005] [Patent Literature]

[0006] [Patent Document 1] Japanese Patent No. 5274557

[0007] [Patent Document 2] Japanese Patent Application Publication No. 2003-31507

[0008] [Patent Document 3] Japanese Patent Application Publication No. 9-909 Summary of the Invention

[0009] [The problem the invention aims to solve]

[0010] To prevent flammable gases from mixing with oxidizing gases, an effective method is to supply inert gases to each gas supply line. However, if separate inert gas supply lines are installed for the flammable gas supply unit and the oxidizing gas supply unit, the installation space for the two gas supply units will be too large.

[0011] The present invention was made in view of the aforementioned problems, and its object is to provide a heat treatment apparatus that can reduce the installation space of gas supply-related elements.

[0012] [Technical means to solve the problem]

[0013] To solve the aforementioned problem, technical solution 1 provides a heat treatment apparatus for heating a substrate, characterized by comprising: a chamber for housing the substrate; a heating unit for heating the substrate housed in the chamber; a combustion-supporting gas line for supplying combustion-supporting gas to the chamber; a combustible gas line for supplying combustible gas to the chamber; and an inert gas line common to both the combustion-supporting gas line and the combustible gas line, wherein inert gas is introduced into the combustion-supporting gas line to replace the contents of the combustion-supporting gas line with inert gas, and inert gas is introduced into the combustible gas line to replace the contents of the combustible gas line with inert gas.

[0014] Furthermore, the invention of technical solution 2 is a heat treatment apparatus as described in technical solution 1, characterized in that it further comprises a bypass pipeline, which branches off from the inert gas pipeline and connects to the combustible gas pipeline, the terminal of the combustion-supporting gas pipeline is connected to the inert gas pipeline, and the bypass pipeline is connected midway along the path of the combustible gas pipeline.

[0015] Furthermore, the invention of technical solution 3 is a heat treatment apparatus as described in technical solution 2, characterized in that: when the combustible gas is supplied to the chamber from the combustible gas pipeline, the inert gas is sent into the combustible gas pipeline from the inert gas pipeline via the bypass pipeline.

[0016] Furthermore, the invention of technical solution 4 is a heat treatment device as described in technical solution 2, characterized in that: a first mass flow controller is provided in the combustion-supporting gas pipeline, a second mass flow controller and a mass flow meter are provided in the combustible gas pipeline, a third mass flow controller is provided in the inert gas pipeline, and the bypass pipeline is connected between the second mass flow controller and the mass flow meter.

[0017] Furthermore, the invention of technical solution 5 is a heat treatment apparatus as invented in technical solution 4, characterized in that it further comprises: a comparison unit that compares the total value of the flow rate of the combustible gas controlled by the second mass flow controller and the flow rate of the inert gas controlled by the third mass flow controller with a measured value obtained by the mass flow meter; and a notification unit that notifies an alarm when the total value is inconsistent with the measured value.

[0018] Furthermore, the invention of technical solution 6 is a heat treatment apparatus as described in technical solution 4, characterized in that: multiple machines installed in the combustion-supporting gas pipeline, including the first mass flow controller, are integrated into a combustion-supporting gas supply unit; multiple machines installed in the combustible gas pipeline, including the second mass flow controller and the mass flow meter, are integrated into a combustible gas supply unit; and multiple machines installed in the inert gas pipeline, including the third mass flow controller, are integrated into an inert gas supply unit.

[0019] Furthermore, the invention of technical solution 7 is a heat treatment apparatus as invented by technical solution 6, characterized in that: at least the second mass flow controller and the mass flow meter are housed in a housing, and nitrogen is supplied to the housing.

[0020] Furthermore, the invention of technical solution 8 is a heat treatment apparatus as described in any one of technical solutions 1 to 7, characterized in that: the combustible gas is ammonia or hydrogen, and the combustion-supporting gas is oxygen, ozone or nitrous oxide.

[0021] [The effects of the invention]

[0022] According to the inventions of technical solutions 1 to 8, since the inert gas pipeline is common to both the combustion-supporting gas pipeline and the combustible gas pipeline, the inert gas pipeline is only required to a minimum size, which can reduce the installation space of gas supply-related elements.

[0023] In particular, according to the invention of technical solution 5, the sum of the flow rates of the combustible gas controlled by the second mass flow controller and the flow rates of the inert gas controlled by the third mass flow controller is compared with the measured value obtained by the mass flow meter. When they are inconsistent, an alarm is triggered, so that abnormalities of the mass flow controller can be properly detected.

[0024] In particular, according to the invention of technical solution 7, the second mass flow controller and mass flow meter are housed in a housing, and nitrogen is supplied to the housing, so that fires or explosions of flammable gases caused by the electric mass flow controller and mass flow meter can be prevented. Attached Figure Description

[0025] Figure 1 This is a diagram showing the main components of the heat treatment apparatus of the present invention.

[0026] Figure 2 This is a diagram showing the structure of the gas supply section.

[0027] Figure 3 This is a diagram showing the explosion-proof structure.

[0028] Figure 4 This is a block diagram showing the structure of the control unit.

[0029] Figure 5 It is a flowchart showing the sequence of processing actions in a heat treatment apparatus. Detailed Implementation

[0030] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0031] Figure 1 This is a diagram showing the main components of the heat treatment apparatus 1 of the present invention. Figure 1 The heat treatment apparatus 1 is a flash lamp annealing apparatus, which heats the semiconductor wafer W, which is a circular plate-shaped substrate, by irradiating it with a flash lamp. The size of the semiconductor wafer W to be processed is not particularly limited, for example, it is φ300mm or φ450mm. Furthermore, Figure 1 In the following figures, for ease of understanding, the size or number of parts may be exaggerated or simplified as needed.

[0032] The heat treatment apparatus 1 includes: a chamber 10 for housing a semiconductor wafer W; a flash irradiation unit 60 for irradiating the semiconductor wafer W within the chamber 10 with flash light; a halogen irradiation unit 70 for irradiating the semiconductor wafer W with halogen light; a gas supply unit 20 for supplying processing gas into the chamber 10; and an exhaust unit 80 for exhausting gas from the chamber 10. Furthermore, the heat treatment apparatus 1 includes a control unit 90 that controls the aforementioned units to perform the flash irradiation.

[0033] The chamber 10 houses the semiconductor wafer W to be processed, and heat-processes the semiconductor wafer W within the chamber 10. The upper opening of the chamber 10 is closed by an upper chamber window 11, and the lower opening of the chamber 10 is closed by a lower chamber window 12. 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 the heat processing space 15. The upper chamber window 11, which forms the top wall of the chamber 10, is a plate-shaped component made of quartz and functions as a quartz window that allows light emitted from the flash irradiation unit 60 to pass through into the heat processing space 15. Similarly, the lower chamber window 12, which forms the bottom of the chamber 10, is also a plate-shaped component made of quartz and functions as a quartz window that allows light from the halogen irradiation unit 70 to pass through into the heat processing space 15.

[0034] A transfer opening 14 for loading and unloading semiconductor wafers W is provided on the side wall of chamber 10. 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 be used to load and unload semiconductor wafers W relative to chamber 10. Furthermore, when the transfer opening 14 is closed, the heat treatment space 15 becomes a sealed space where ventilation to the outside is blocked.

[0035] Inside the chamber 10, a crystal holder 18 is provided to hold the semiconductor wafer W. The crystal holder 18 is a circular plate-shaped component formed of quartz. The diameter of the crystal holder 18 is slightly larger than the diameter of the semiconductor wafer W. The semiconductor wafer W is held in the chamber 10 in a horizontal orientation (the normal direction of the main surface is consistent with the vertical direction) using the crystal holder 18.

[0036] A flash irradiation unit 60 is disposed above the chamber 10. The flash irradiation unit 60 is composed of a light source consisting of multiple flash lamps FL and a reflector 62 disposed to cover the light source. The flash irradiation unit 60 illuminates the semiconductor wafer W held by the crystal pedestal 18 inside the chamber 10 through the flash lamps FL through the upper chamber window 11 made of quartz, thereby heating the surface of the semiconductor wafer W.

[0037] The multiple flash lamps FL are rod-shaped lamps with elongated cylindrical shapes, and are arranged in a planar manner, parallel to each other along the main surface (i.e., along the horizontal direction) of the semiconductor wafer W held by the crystal seat 18. Therefore, the plane formed by the arrangement of the flash lamps FL is also a horizontal plane.

[0038] A flash lamp (FL) comprises: a cylindrical glass tube (discharge tube) containing xenon gas, with an anode and cathode connected to a capacitor at both ends; and a trigger electrode attached to the outer circumference of the glass tube. Because xenon gas is an electrical insulator, the glass tube is normally not energized even when a charge accumulates in the capacitor. However, when a high voltage is applied to the trigger electrode, breaking the insulation, the charge accumulated in the capacitor instantaneously flows into the glass tube, emitting light through the excitation of xenon atoms or molecules. This type of flash lamp (FL) is characterized by converting pre-stored electrostatic energy in the capacitor into extremely short light pulses of 0.1 to 100 milliseconds, resulting in extremely intense light compared to continuously lit light sources like halogen lamps (HL). In other words, the flash lamp (FL) is a pulsed light lamp that emits light instantaneously in a very short time, less than one second. Furthermore, the emission time of the flash lamp (FL) can be adjusted according to the coil constant of the lamp power supply that powers the flash lamp (FL).

[0039] Reflector 62 is positioned above the multiple flash lamps (FLs) in a manner that covers the entire flash unit. The basic function of reflector 62 is to reflect the flash emitted from the multiple flash lamps (FLs) toward the photothermal processing space 15. Reflector 62 is formed from an aluminum alloy plate, and its surface (the side facing the flash lamps (FLs)) has been roughened by sandblasting.

[0040] A halogen irradiation unit 70 is disposed below the chamber 10. The halogen irradiation unit 70 contains multiple halogen lamps HL. The halogen irradiation unit 70 uses the multiple halogen lamps HL to irradiate the heat treatment space 15 from below the chamber 10 through the lower chamber window 12, thereby heating the semiconductor wafer W.

[0041] The multiple halogen lamps HL are rod-shaped lamps with elongated cylindrical shapes, and are arranged in a planar manner, parallel to each other along the main surface of the semiconductor wafer W held by the crystal pedestal 18, with their respective length directions. 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 pattern on two layers.

[0042] Each halogen lamp (HL) is a light source that emits light by incandescent through a filament housed inside a glass tube. The glass tube is sealed with a gas obtained by introducing trace amounts of halogen elements (iodine, bromine, etc.) into an inert gas such as nitrogen or argon. By introducing halogen elements, filament breakage can be suppressed, and the filament temperature can be set to a high temperature. Therefore, halogen lamps (HL) have a longer lifespan and can continuously emit strong light compared to ordinary incandescent bulbs. In other words, halogen lamps (HL) are continuously lit lamps that emit light for at least one second.

[0043] The exhaust section 80 includes a vacuum pump 81 and an exhaust valve 82. By activating the vacuum pump 81 and opening the exhaust valve 82, the gas inside the chamber 10 is discharged. When no gas is supplied from the gas supply section 20, and the gas in the heat treatment space 15, which is a sealed space, is discharged by the vacuum pump 81, the pressure inside the chamber 10 can be reduced to a vacuum atmosphere.

[0044] The gas supply unit 20 has three types of gas supply units: an oxidizing gas supply unit 30, a combustible gas supply unit 40, and an inert gas supply unit 50. Figure 2 This is a diagram showing the configuration of the gas supply unit 20.

[0045] Chamber 10 is connected to a gas supply line 21. The base of the gas supply line 21 branches into three gas lines. Specifically, the gas supply line 21 is connected to a combustion-supporting gas line 31, a combustible gas line 41, and an inert gas line 51. The combustion-supporting gas line 31, the combustible gas line 41, the inert gas line 51, and the gas supply line 21 are all piping for supplying gas.

[0046] The end of the combustion-supporting gas line 31 is connected to the gas supply line 21, and the base is connected to the oxygen supply source 32. In this embodiment, the combustion-supporting gas line 31 supplies oxygen (O2) as a combustion-supporting gas to the chamber 10. A first mass flow controller 33, a valve 34, and a valve 35 are disposed along the path of the combustion-supporting gas line 31.

[0047] The end of the combustible gas pipeline 41 is connected to the gas supply pipeline 21, and the base is connected to the ammonia supply source 42. In this embodiment, the combustible gas pipeline 41 supplies ammonia (NH3) as a combustible gas to the chamber 10. A second mass flow controller 43, a valve 44, a mass flow meter 45, and a valve 46 are disposed along the path of the combustible gas pipeline 41.

[0048] The inert gas line 51 is connected at its end to the gas supply line 21 and at its base to the nitrogen supply source 52. The inert gas line 51 is also connected to the terminals of the combustible gas line 41 and the combustion-supporting gas line 31. In this embodiment, the inert gas line 51 supplies nitrogen (N2) as the inert gas. A third mass flow controller 53 and a valve 54 are disposed along the path of the inert gas line 51.

[0049] Additionally, bypass line 25 branches off from the path of inert gas line 51 and connects to the path of combustible gas line 41. Bypass line 25 branches off from the path of inert gas line 51 at a position downstream of the third mass flow controller 53. Bypass line 25 connects between the second mass flow controller 43 and the mass flow meter 45 in the path of combustible gas line 41. A valve 26 is interposed along the path of bypass line 25.

[0050] The combustion-supporting gas supply unit 30 comprises a first mass flow controller 33 and a valve 34 installed in the combustion-supporting gas pipeline 31. The combustible gas supply unit 40 comprises a second mass flow controller 43, a valve 44, a mass flow meter 45, and a valve 46 installed in the combustible gas pipeline 41, and a valve 26 installed in the bypass pipeline 25. The inert gas supply unit 50 comprises a third mass flow controller 53 and a valve 54 installed in the inert gas pipeline 51.

[0051] The combustion-supporting gas supply unit 30, the combustible gas supply unit 40, and the inert gas supply unit 50 are each constructed by integrating multiple machines, such as mass flow controllers, onto a plate-shaped component. This reduces the space required for gas supply-related components. Strictly speaking, for example, the second mass flow controller 43 and the mass flow meter 45 are not connected via piping, but are essentially equivalent to being connected via piping. In this embodiment, the second mass flow controller 43 and the mass flow meter 45 are considered to be installed in the combustible gas pipeline 41.

[0052] In addition, such as Figure 3 As shown, at least the machine including the second mass flow controller 43 and the mass flow meter 45 is housed inside the housing 47. The housing 47 is filled with nitrogen supplied from the nitrogen supply unit 48. The second mass flow controller 43 and the mass flow meter 45 are electrically operated machines, and there are concerns that they could become sources of combustion. That is, there are concerns that if ammonia, a flammable gas, leaks from a joint of the flammable gas pipeline 41, a spark ignited by the second mass flow controller 43 or the mass flow meter 45 could cause a fire or explosion. To prevent this, at least the second mass flow controller 43 and the mass flow meter 45 are housed inside the housing 47, and the housing 47 is filled with nitrogen. The occurrence of a fire or explosion requires the presence of the flammable gas itself as a combustible material, a combustion source, and oxygen as an oxidizing gas. If the housing 47 housing the second mass flow controller 43 and the mass flow meter 45 is filled with nitrogen, the absence of an oxidizing gas will prevent a fire or explosion. In addition, to prevent explosions, the nitrogen supplied from the nitrogen supply unit 48 may have a lower purity than the nitrogen supplied from the nitrogen supply source 52.

[0053] Return to Figure 1 The control unit 90 controls the various operating mechanisms installed in the heat treatment apparatus 1. Figure 4 This is a block diagram showing the configuration of the control unit 90. The hardware configuration of the control unit 90 is the same as that of a general computer. That is, the control unit 90 is composed of a CPU (Central Processing Unit) for performing various arithmetic operations, a ROM (Read Only Memory) for storing basic programs, a RAM (Random Access Memory) for storing various information, and a disk pre-stored with control applications or data. The heat treatment device 1 is processed by the CPU of the control unit 90 executing a predetermined processing program.

[0054] like Figure 4As shown, the control unit 90 includes a comparison unit 91 and a notification unit 92. The comparison unit 91 and the notification unit 92 are functional processing units implemented by the CPU of the control unit 90 executing a predetermined processing program. The processing content of the comparison unit 91 and the notification unit 92 will be further described below.

[0055] In addition, the control unit 90 is electrically connected to a first mass flow controller 33, a second mass flow controller 43, a third mass flow controller 53, a mass flow meter 45, and valves installed in the gas supply unit 20. The control unit 90 controls the gas flow rate of each mass flow controller to a predetermined set value and acquires the measured value from the mass flow meter 45. The control unit 90 controls the opening and closing of each valve.

[0056] Furthermore, the control unit 90 is connected to a display unit 99 and an input unit 98. The control unit 90 displays various information on the display unit 99. The operator of the heat treatment apparatus 1 can check the information displayed on the display unit 99 while inputting various commands or parameters from the input unit 98. The input unit 98 can be, for example, a keyboard or a mouse. The display unit 99 can be, for example, a liquid crystal display. In this embodiment, the display unit 99 and the input unit 98 are both liquid crystal touch panels provided on the outer wall of the heat treatment apparatus 1, thus combining the functions of both.

[0057] Next, the processing operation of heat treatment apparatus 1 will be explained. Figure 5 This is a flowchart illustrating the sequence of processing operations of the heat treatment apparatus 1. Here, the sequence of supplying gas to the chamber 10 of the heat treatment apparatus 1 is mainly explained.

[0058] First, a semiconductor wafer W is moved into the chamber 10 (step S1). The semiconductor wafer W being processed is a silicon semiconductor substrate. The semiconductor wafer W is moved into the chamber 10 through the transfer opening 14 by a transfer robot (not shown) and held on the wafer holder 18. The transfer robot that delivers the semiconductor wafer W to the wafer holder 18 withdraws from the chamber 10, and the transfer opening 14 is closed by a gate valve, thereby making the heat treatment space 15 inside the chamber 10 a sealed space.

[0059] After the semiconductor wafer W is placed into the chamber 10, the chamber 10 and the combustion gas line 31 are evacuated under vacuum (step S2). In step S2, with valve 35 open and valves 34, 44, 46, 54, and 26 closed, vacuum pump 81 is used to evacuate the chamber 10 and the downstream portion of the combustion gas line 31 from valve 34. By evacuating the combustion gas line 31 under vacuum, residual oxygen between valves 34 and 35 in the combustion gas line 31 is removed.

[0060] Next, the vacuum venting of vacuum pump 81 is stopped, and the combustion-supporting gas line 31 is replaced with nitrogen (step S3). In step S3, nitrogen is supplied to chamber 10 from inert gas line 51 by opening valve 54, and nitrogen is also supplied to combustion-supporting gas line 31 from inert gas line 51. As a result, the space between valves 34 and 35 of combustion-supporting gas line 31 is filled with nitrogen, and the oxygen remaining between valves 34 and 35 is replaced with nitrogen. Replacing combustion-supporting gas line 31 with nitrogen after vacuum venting is to reliably prevent ammonia, as a combustible gas, from mixing with oxygen, as a combustion-supporting gas, when ammonia is supplied in subsequent processes.

[0061] After replacing the combustion-supporting gas line 31 with nitrogen, valves 35 and 54 are closed, and the chamber 10 is evacuated again using vacuum pump 81. Then, ammonia is supplied to the chamber 10 (step S4). In step S4, ammonia is supplied to the chamber 10 from the combustible gas line 41 by opening valves 44 and 46. The combustion-supporting gas line 31 is evacuated before the ammonia is supplied, and then replaced with nitrogen, thus reliably preventing the supplied ammonia from mixing with the oxygen from the combustion-supporting gas line 31.

[0062] At this point, from the viewpoint of preventing fires or explosions caused by ammonia, a flammable gas, it is necessary to consider not only the mixing with oxygen from the flammable gas pipeline 31, but also the inflow of atmosphere into the chamber 10 due to damage to its constituent parts. In this embodiment, to prevent the formation of an explosive mixture when atmosphere flows into the chamber 10, the ammonia is diluted with nitrogen and supplied to the chamber 10 so that the ammonia concentration does not reach the explosion limit. Specifically, after opening valve 26, nitrogen is introduced into the flammable gas pipeline 41 through bypass pipeline 25. As a result, the ammonia flowing in the flammable gas pipeline 41 is mixed with the nitrogen introduced from bypass pipeline 25, and the ammonia is diluted and supplied to the chamber 10.

[0063] When a mixture of ammonia and nitrogen is supplied to chamber 10, the flow rates of ammonia and nitrogen are controlled by a second mass flow controller 43 and a third mass flow controller 53, respectively, to ensure that the ammonia concentration in the mixture does not reach the explosion limit. In this embodiment, to reliably prevent abnormal mixing ratios caused by malfunctions of the second mass flow controller 43 or the third mass flow controller 53, which could lead to an ammonia concentration exceeding the explosion limit, a mass flow meter 45 is installed in the flammable gas pipeline 41 to monitor the flow rate of the mixed gas.

[0064] The comparison unit 91 of the control unit 90 calculates the total flow rate of ammonia controlled by the second mass flow controller 43 and the total flow rate of nitrogen controlled by the third mass flow controller 53. The mass flow meter 45 measures the flow rate of the mixture of ammonia and nitrogen. The comparison unit 91 compares this total value with the measured value obtained by the mass flow meter 45. If both the second and third mass flow controllers 43 and 53 are operating normally, the total value and the measured value obtained by the mass flow meter 45 should be consistent. If the total value and the measured value are inconsistent, it is considered that either the second or third mass flow controller 43 has malfunctioned. Therefore, when the comparison result of the comparison unit 91 deviates from the measured value obtained by the mass flow meter 45 by a preset threshold, the alarm unit 92 of the control unit 90 issues an alarm.

[0065] After a mixture of ammonia and nitrogen is supplied to chamber 10 to form an ammonia atmosphere, heat treatment of the semiconductor wafer W is performed (step S5). During the heat treatment of the semiconductor wafer W, the halogen lamp HL of the halogen irradiation section 70 is first lit to begin preheating (auxiliary heating) of the semiconductor wafer W. Light emitted from the halogen lamp HL passes through the quartz lower chamber window 12 and the crystal seat 18 and irradiates the lower surface of the semiconductor wafer W. By receiving light irradiation from the halogen lamp HL, the semiconductor wafer W is preheated and its temperature rises. After the temperature of the semiconductor wafer W rises and reaches the predetermined preheating temperature, the temperature of the semiconductor wafer W is maintained at the preheating temperature for about several seconds.

[0066] After a predetermined time has elapsed since the semiconductor wafer W reaches its preheating temperature, the flash lamp FL of the flash irradiation unit 60 irradiates the surface of the semiconductor wafer W held by the crystal pedestal 18. The flash irradiated by the flash lamp FL is a strong flash obtained by converting electrostatic energy pre-stored in a capacitor into an extremely short light pulse. The irradiation time is approximately 0.1 milliseconds to 100 milliseconds. By irradiating the semiconductor wafer W with this extremely short and intense flash, the surface temperature of the semiconductor wafer W rises instantaneously to the processing temperature and then drops rapidly. By preheating and flash heating the semiconductor wafer W in an ammonia atmosphere, a silicon nitride (Si3N4) thin film is formed on the surface of the semiconductor wafer W.

[0067] After the flash heating process, the halogen lamp HL is extinguished after a specified time. Therefore, the temperature of the semiconductor wafer W also decreases from the preheating temperature. Subsequently, the chamber 10 and the flammable gas line 41 are evacuated under vacuum (step S6). In step S6, vacuum pump 81 is used to vent gas by closing valves 44 and 26, and vacuum venting is performed on the downstream portion of valve 44 in the chamber 10 and the flammable gas line 41. By evacuating the flammable gas line 41 under vacuum, the ammonia gas remaining on the downstream portion of valve 44 in the flammable gas line 41 can be discharged.

[0068] Next, the vacuum venting of vacuum pump 81 is stopped, and the combustible gas line 41 is replaced with nitrogen (step S7). In step S7, nitrogen is introduced into the combustible gas line 41 from the inert gas line 51 via the bypass line 25 by opening valve 26, and nitrogen is supplied to chamber 10 through the combustible gas line 41. As a result, the space between valves 26, 44, and 46 is filled with nitrogen, and the ammonia gas remaining between valves 44 and 46 in the combustible gas line 41 is replaced with nitrogen. Replacing the combustible gas line 41 with nitrogen after vacuum venting is to reliably prevent the ammonia gas, which is a combustible gas, from mixing with the oxygen gas, which is a combustion-supporting gas, when oxygen is supplied in subsequent processes.

[0069] After replacing the combustible gas line 41 with nitrogen, oxygen is supplied to chamber 10 (step S8). In step S8, oxygen is supplied to chamber 10 from the combustion-supporting gas line 31 by closing valves 26 and 46 and opening valves 34 and 35. The combustible gas line 41 is evacuated before oxygen supply, and then replaced with nitrogen, thus reliably preventing the supplied oxygen from mixing with ammonia from the combustible gas line 41. When supplying oxygen to chamber 10, valve 54 can also be opened to supply a mixture of oxygen and nitrogen to chamber 10.

[0070] After oxygen is supplied to chamber 10 to form an oxygen atmosphere, a second heat treatment of semiconductor wafer W is performed (step S9). The heat treatment of semiconductor wafer W in step S9 is largely the same as the heat treatment in step S5. By preheating and flash heating semiconductor wafer W in an oxygen atmosphere, a silicon oxide (SiO2) thin film is formed on the previously formed silicon nitride film substrate.

[0071] After the second heat treatment of semiconductor wafer W is completed, the halogen lamp HL is also turned off, and the temperature of semiconductor wafer W drops. Additionally, by using vacuum pump 81 to remove the oxygen atmosphere from chamber 10, and closing valves 34 and 35 while opening valve 54, the atmosphere in chamber 10 is replaced with nitrogen. Once the temperature of semiconductor wafer W drops below a predetermined level, the heat-treated semiconductor wafer W is removed from the transfer opening 14, completing the heat treatment (step S10).

[0072] In this embodiment, nitrogen is supplied from the inert gas line 51 to the combustion-supporting gas line 31, replacing the combustion-supporting gas line 31 with nitrogen. Similarly, nitrogen is supplied from the same inert gas line 51 to the combustible gas line 41, replacing the combustible gas line 41 with nitrogen. That is, a single, shared inert gas line 51 is used for both the combustion-supporting gas line 31 and the combustible gas line 41, instead of separate inert gas lines for each. Therefore, the space required for gas supply-related components can be reduced.

[0073] Furthermore, gas supply-related elements, such as the mass flow controllers installed in the combustion-supporting gas pipeline 31, the combustible gas pipeline 41, and the inert gas pipeline 51, are integrated into a single unit. This also reduces the space required for installing gas supply-related elements.

[0074] The embodiments of the present invention have been described above, but the present invention can be modified in various ways other than those described without departing from its spirit. For example, in the described embodiments, ammonia is used as the combustible gas, but it is not limited to this; the combustible gas may also be hydrogen (H2), etc. Furthermore, in the described embodiments, oxygen is used as the combustion-supporting gas, but it is not limited to this; the combustion-supporting gas may also be ozone (O3) or nitrous oxide (N2O), etc. Moreover, in the described embodiments, nitrogen is used as the inert gas, but it is not limited to this; the inert gas may also be argon (Ar) or helium (He), etc.

[0075] In addition, in the above embodiment, a halogen lamp HL with a filament is used as a continuous lighting lamp that emits light for more than 1 second to preheat the semiconductor wafer W. However, it is not limited to this. A discharge arc lamp (e.g., a xenon arc lamp) can also be used instead of the halogen lamp HL as a continuous lighting lamp for preheating.

[0076] Furthermore, the substrate to be processed by the heat treatment apparatus 1 is not limited to semiconductor wafers, but may also be a glass substrate or a solar substrate used in flat panel displays such as liquid crystal display devices.

[0077] In addition, in the above embodiment, the semiconductor wafer W is heated by irradiating it with a flash inside the chamber 10, but it is not limited to this. It is also possible to heat the semiconductor wafer W housed in the chamber 10 by irradiating it with light from a halogen lamp HL.

[0078] [Explanation of Symbols]

[0079] 1. Heat treatment apparatus

[0080] 10 chambers

[0081] 25 Bypass pipeline

[0082] 30 Combustion-supporting gas supply units

[0083] 31 Combustion-supporting gas pipelines

[0084] 33 First mass flow controller

[0085] 40 Combustible Gas Supply Unit

[0086] 41. Flammable gas pipelines

[0087] 43. Second mass flow controller

[0088] 45 Mass Flow Meter

[0089] 47. Casing

[0090] 48 Nitrogen Supply Department

[0091] 50 Inert Gas Supply Units

[0092] 51 Inert Gas Pipeline

[0093] 53. Third mass flow controller

[0094] 60 Flash Irradiation Section

[0095] 70 Halogen Irradiation Section

[0096] 90 Control Department

[0097] 91 Comparative Section

[0098] 92. Reporting Department

[0099] FL flash

[0100] HL halogen lamp

[0101] W Semiconductor wafer.

Claims

1. A heat treatment apparatus, characterized in that: Heating the substrate, and having the following characteristics: Chamber, housing the substrate; The heating unit heats the substrate housed in the chamber. A combustion-supporting gas pipeline supplies combustion-supporting gas to the chamber; A flammable gas pipeline supplies flammable gas to the chamber; and The combustion-supporting gas pipeline and the combustible gas pipeline share an inert gas pipeline. Inert gas is introduced into the combustion-supporting gas pipeline to replace it with inert gas, and inert gas is also introduced into the combustible gas pipeline to replace it with inert gas. The combustion-supporting gas pipeline is equipped with a first mass flow controller. The flammable gas pipeline is equipped with a second mass flow controller and a mass flow meter. The inert gas pipeline is equipped with a third mass flow controller. Multiple machines, including the first mass flow controller, installed in the combustion-supporting gas pipeline are integrated into a combustion-supporting gas supply unit. Multiple machines, including the second mass flow controller and the mass flow meter, installed in the flammable gas pipeline are integrated into a flammable gas supply unit. Multiple machines, including the third mass flow controller, installed in the inert gas pipeline are integrated into an inert gas supply unit. At least the second mass flow controller and the mass flow meter are housed within the housing. Nitrogen gas is supplied to the inside of the shell.

2. The heat treatment apparatus according to claim 1, characterized in that: It also includes a bypass line that branches off from the inert gas line and connects to the combustible gas line. The terminal of the combustion-supporting gas pipeline is connected to the inert gas pipeline, and the bypass pipeline is connected midway along the path of the combustible gas pipeline.

3. The heat treatment apparatus according to claim 2, characterized in that: When the combustible gas is supplied to the chamber from the combustible gas line, the inert gas is sent into the combustible gas line from the inert gas line via the bypass line.

4. The heat treatment apparatus according to claim 2, characterized in that: The bypass line is connected between the second mass flow controller and the mass flow meter.

5. The heat treatment apparatus according to claim 4, characterized in that... It also has: The comparison unit compares the sum of the flow rates of the combustible gas controlled by the second mass flow controller and the flow rates of the inert gas controlled by the third mass flow controller with the measured value obtained using the mass flow meter. as well as The reporting department will issue an alarm when the total value is inconsistent with the measured value.

6. The heat treatment apparatus according to any one of claims 1 to 5, characterized in that: The flammable gas is ammonia or hydrogen. The combustion-supporting gas is oxygen, ozone, or nitrous oxide.

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