Emissivity adjustment method

Abstract

To provide an emissivity adjustment method that can adjust emissivity to be set to a radiation thermometer with high accuracy.SOLUTION: An emissivity adjustment method is configured to: perform cycle heating processing to raise a temperature of a measurement wafer having a thermocouple attached by light irradiation from a halogen lamp, and then cool the temperature thereof; while performing the cycle heating processing to the measurement wafer, measure the temperature of the measurement wafer having the temperature raised by the thermocouple, and the radiation thermometer; when a temperature difference between a true temperature of the measurement wafer measured by the thermocouple and a temperature thereof measured by the radiation thermometer is within a prescribed threshold, determine that emissivity being set to the radiation thermometer is accurate; end adjustment processing; and when the temperature difference exceeds the prescribed threshold, correct the emissivity set to the radiation thermometer in accordance with the temperature difference.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to an emissivity adjustment method for adjusting the emissivity set in a radiation thermometer that is installed in a heat treatment device and measures the temperature of a thin precision electronic substrate (hereinafter simply referred to as a "substrate") such as a semiconductor wafer. [Background technology]

[0002] In heat treatment equipment (e.g., lamp annealing equipment) that heats semiconductor wafers, it is important to properly manage the wafer temperature. To do this, it is necessary to accurately measure the temperature of the semiconductor wafer. One possible method for accurately measuring the temperature of a semiconductor wafer is to use a thermocouple to measure the wafer temperature. However, direct contact of a thermocouple with the semiconductor wafer not only causes contamination, but also makes it impossible to transport the semiconductor wafer, making it difficult to use a thermocouple to measure the temperature of the semiconductor wafer. For this reason, a radiation thermometer that measures the temperature of a semiconductor wafer without contact is widely used as a tool for measuring the temperature of the semiconductor wafer during heat treatment.

[0003] A radiation thermometer has a problem that the measurement accuracy is likely to be lower than that of a thermocouple that directly contacts the object to be measured. For this reason, Patent Document 1 discloses that temperature calibration data is created based on the actual temperature measured by a thermocouple, and the measured temperature of the radiation thermometer is corrected using the data. Patent Document 2 discloses that the measured value of the radiation thermometer is corrected using the error rate between the thermocouple and the radiation thermometer as a correction rate. Furthermore, Patent Document 3 discloses that the correction value of the radiation thermometer is calculated based on the measured temperature of the thermocouple. All of these disclose that the thermocouple can accurately measure the actual temperature, and correct the measured temperature of the radiation thermometer based on the measured value of the thermocouple. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 62-110127 [Patent Document 2] Japanese Patent Application Publication No. 2-298829 [Patent Document 3] Japanese Patent Application Publication No. 3-232968 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in reality, the emissivity of the semiconductor wafer being measured varies minutely depending on various factors such as the surface condition and temperature. For this reason, even if the temperature measured by the radiation thermometer is corrected based on the measurement value of the thermocouple, it is difficult to accurately measure the temperature of the semiconductor wafer during heat treatment using the radiation thermometer. In order to accurately measure the temperature of the semiconductor wafer during heat treatment using the radiation thermometer, it is necessary to set the accurate emissivity of the semiconductor wafer at that time in the radiation thermometer.

[0006] The present invention has been made in consideration of the above problems, and an object of the present invention is to provide an emissivity adjustment method that can adjust the emissivity set in a radiation thermometer with high accuracy. [Means for solving the problem]

[0010] Also, claims 1The invention relates to an emissivity adjustment method for adjusting the emissivity set in a radiation thermometer installed in a heat treatment device, the method comprising: a carrying-in step of carrying a substrate having a thermocouple attached thereto into a chamber; a dummy processing step of repeating a first number of cycles of a heat treatment in which the substrate is heated and then cooled by irradiation with light from a continuously lit lamp; and a first adjustment step of repeating a second number of cycles of a heat treatment in which the substrate is heated and then cooled by irradiation with light from the continuously lit lamp, the first adjustment step comprising a first comparison step of comparing a first measured temperature obtained by measuring the heated temperature of the substrate by the thermocouple with a second measured temperature obtained by measuring the temperature of the substrate by the radiation thermometer, the first adjustment step comprising: terminating the adjustment of the emissivity set in the radiation thermometer if a temperature difference between the first measured temperature and the second measured temperature is within a predetermined threshold value in all cycles of the second number of cycles; and correcting the emissivity set in the radiation thermometer if a temperature difference between the first measured temperature and the second measured temperature exceeds the threshold value in at least one cycle of the second number of cycles.

[0011] Also, claims 2 The invention is as follows: 1 In the emissivity adjustment method according to the present invention, in the first adjustment step, when a temperature difference between the first measured temperature and the second measured temperature exceeds the threshold value, the emissivity set in the radiation thermometer is corrected by a preset change amount.

[0012] Also, claims 3 The invention is as follows: 2 In the emissivity adjustment method according to the present invention, in the first adjustment step, when the first measured temperature is higher than the second measured temperature, the emissivity set in the radiation thermometer is reduced.

[0013] Also, claims 4 The invention is as follows: 3The emissivity adjustment method according to the present invention further comprises a second adjustment step of repeating a heat treatment of raising and lowering the temperature of the substrate by irradiating it with light from the continuously lit lamp for the second number of cycles after correcting the emissivity set in the radiation thermometer in the first adjustment step, the second adjustment step comprising a second comparison step of comparing the first measured temperature with the second measured temperature for each cycle, and the second adjustment step terminates the adjustment of the emissivity set in the radiation thermometer if a temperature difference between the first measured temperature and the second measured temperature is within the threshold value in all cycles of the second number of cycles, and further corrects the emissivity set in the radiation thermometer if a temperature difference between the first measured temperature and the second measured temperature exceeds the threshold value in at least one cycle of the second number of cycles.

[0014] Also, claims 5 The invention is as follows: 4 In the emissivity adjustment method according to the present invention, in the second adjustment step, if the temperature difference between the first measured temperature and the second measured temperature exceeds the threshold value, the emissivity at which the temperature difference between the first measured temperature and the second measured temperature becomes 0 is set in the radiation thermometer, the emissivity being obtained by linear approximation based on the temperature difference between the first measured temperature and the second measured temperature in the first comparison step and the temperature difference between the first measured temperature and the second measured temperature in the second comparison step.

[0015] Also, claims 6 The invention is as follows: 5 In the emissivity adjustment method of the present invention, an alarm is issued when a temperature difference between the first measured temperature and the second measured temperature in the first comparison step and a temperature difference between the first measured temperature and the second measured temperature in the second comparison step are the same value.

[0016] Also, claims 7 The invention is as follows: 6In the emissivity adjustment method of the present invention, an alarm is issued when the emissivity set in the radiation thermometer corrected in the first adjustment step or the second adjustment step becomes larger than a predetermined upper limit value or becomes smaller than a predetermined lower limit value.

[0017] Also, claims 8 The invention is as follows: 1 From claims 7 In the emissivity adjustment method according to any one of the above-mentioned inventions, when the temperature of the substrate measured by the thermocouple during the dummy processing step differs from the temperature of the substrate measured by the radiation thermometer, the emissivity set in the radiation thermometer is pre-corrected. Effect of the Invention

[0019] Claim 1 From claims 8 According to the invention, when the temperature difference between the first measured temperature of the substrate measured by a thermocouple and the second measured temperature of the substrate measured by a radiation thermometer exceeds a threshold value, the emissivity set in the radiation thermometer is corrected based on the actual temperature of the substrate, and the emissivity set in the radiation thermometer can be adjusted with high accuracy. [Brief description of the drawings]

[0020] [Figure 1] 1 is a vertical cross-sectional view showing a configuration of a heat treatment apparatus 1 incorporating a radiation thermometer which is a target of an emissivity adjustment method according to the present invention. [Diagram 2] FIG. 2 is a perspective view showing the overall appearance of a holding portion. [Diagram 3] FIG. [Figure 4] FIG. [Diagram 5] FIG. [Figure 6] FIG. [Figure 7] FIG. 2 is a plan view showing an arrangement of a plurality of halogen lamps. [Figure 8] 10 is a flowchart showing a procedure for adjusting the emissivity set in the radiation thermometer. [Figure 9] 10 is a flowchart showing a procedure for adjusting the emissivity set in the radiation thermometer. [Figure 10] 10 is a flowchart showing a procedure for adjusting the emissivity set in the radiation thermometer. [Figure 11] FIG. 13 is a diagram showing temperature changes of a measuring wafer during cyclic heating in an adjustment process. [Figure 12] FIG. 13 is a diagram illustrating an example of a correction straight line. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0022] First, the configuration of a heat treatment apparatus 1 incorporating a radiation thermometer that is the subject of the emissivity adjustment method according to the present invention will be described. FIG. 1 is a vertical cross-sectional view showing the configuration of the heat treatment apparatus 1. The heat treatment apparatus 1 in FIG. 1 is a flash lamp annealing apparatus that heats a disk-shaped semiconductor wafer W as a substrate by irradiating the semiconductor wafer W with flash light. The size of the semiconductor wafer W to be treated is not particularly limited, but is, for example, φ300 mm or φ450 mm. In FIG. 1 and the subsequent figures, the dimensions and number of each part are exaggerated or simplified as necessary for ease of understanding.

[0023] The heat treatment apparatus 1 includes a chamber 6 that accommodates a semiconductor wafer W, a flash heating unit 5 that incorporates a plurality of flash lamps FL, and a halogen heating unit 4 that incorporates a plurality of halogen lamps HL. The flash heating unit 5 is provided on the upper side of the chamber 6, and the halogen heating unit 4 is provided on the lower side. The heat treatment apparatus 1 also includes, inside the chamber 6, a holding unit 7 that holds the semiconductor wafer W in a horizontal position, and a transfer mechanism 10 that transfers the semiconductor wafer W between the holding unit 7 and the outside of the apparatus. The heat treatment apparatus 1 also includes a control unit 3 that controls the respective operating mechanisms provided in the halogen heating unit 4, the flash heating unit 5, and the chamber 6 to perform heat treatment of the semiconductor wafer W.

[0024] The chamber 6 is configured by mounting quartz chamber windows on the top and bottom of a cylindrical chamber side portion 61. The chamber side portion 61 has a roughly cylindrical shape with openings at the top and bottom, with an upper chamber window 63 mounted and closed at the upper opening, and a lower chamber window 64 mounted and closed at the lower opening. The upper chamber window 63 constituting the ceiling of the chamber 6 is a disk-shaped member made of quartz, and functions as a quartz window that transmits the flash light emitted from the flash heating unit 5 into the chamber 6. The lower chamber window 64 constituting the floor of the chamber 6 is also a disk-shaped member made of quartz, and functions as a quartz window that transmits the light from the halogen heating unit 4 into the chamber 6.

[0025] In addition, a reflective ring 68 is attached to the upper part of the inner wall surface of the chamber side part 61, and a reflective ring 69 is attached to the lower part. Both of the reflective rings 68, 69 are formed in an annular shape. The upper reflective ring 68 is attached by fitting it from the upper side of the chamber side part 61. On the other hand, the lower reflective ring 69 is attached by fitting it from the lower side of the chamber side part 61 and fastening it with screws (not shown). In other words, both of the reflective rings 68, 69 are detachably attached to the chamber side part 61. The inner space of the chamber 6, i.e., the space surrounded by the upper chamber window 63, the lower chamber window 64, the chamber side part 61, and the reflective rings 68, 69, is defined as a heat treatment space 65.

[0026] By mounting the reflecting rings 68, 69 on the chamber side portion 61, a recess 62 is formed on the inner wall surface of the chamber 6. That is, the recess 62 is formed by a central portion of the inner wall surface of the chamber side portion 61 where the reflecting rings 68, 69 are not mounted, the lower end surface of the reflecting ring 68, and the upper end surface of the reflecting ring 69. The recess 62 is formed in an annular shape along the horizontal direction on the inner wall surface of the chamber 6, and surrounds the holder 7 that holds the semiconductor wafer W. The chamber side portion 61 and the reflecting rings 68, 69 are formed from a metal material (e.g., stainless steel) that has excellent strength and heat resistance.

[0027] Further, a transfer opening (furnace port) 66 for carrying a semiconductor wafer W into and out of the chamber 6 is formed in the chamber side portion 61. The transfer opening 66 can be opened and closed by a gate valve 185. The transfer opening 66 is connected in communication with the outer circumferential surface of the recess 62. Therefore, when the gate valve 185 opens the transfer opening 66, the semiconductor wafer W can be carried into and out of the heat treatment space 65 through the transfer opening 66 and the recess 62. Furthermore, when the gate valve 185 closes the transfer opening 66, the heat treatment space 65 in the chamber 6 becomes an airtight space.

[0028] Further, a through hole 61a is formed in the chamber side 61. A radiation thermometer 20 is attached to the portion of the outer wall surface of the chamber side 61 where the through hole 61a is provided. The through hole 61a is a cylindrical hole for guiding infrared light radiated from the lower surface of a semiconductor wafer W held by a susceptor 74 described later to the radiation thermometer 20. The through hole 61a is provided at an incline with respect to the horizontal direction so that the axis of the through hole 61a intersects with the main surface of the semiconductor wafer W held by the susceptor 74. Thus, the radiation thermometer 20 is provided obliquely below the susceptor 74. A transparent window 21 made of a barium fluoride material that transmits infrared light in a wavelength range that can be measured by the radiation thermometer 20 is attached to the end of the through hole 61a facing the heat treatment space 65.

[0029] Further, a gas supply hole 81 is formed in the upper part of the inner wall of the chamber 6 to supply a processing gas to the heat treatment space 65. The gas supply hole 81 is formed at a position above the recessed portion 62, and may be provided in the reflecting ring 68. The gas supply hole 81 is connected to a gas supply pipe 83 through a buffer space 82 formed in an annular shape inside the side wall of the chamber 6. The gas supply pipe 83 is connected to a processing gas supply source 85. A valve 84 is inserted in the middle of the gas supply pipe 83. When the valve 84 is opened, the processing gas is supplied from the processing gas supply source 85 to the buffer space 82. The processing gas that has flowed into the buffer space 82 flows in a spreading manner in the buffer space 82, which has a smaller fluid resistance than the gas supply hole 81, and is supplied from the gas supply hole 81 to the heat treatment space 65. As the processing gas, for example, an inert gas such as nitrogen (N2), a reactive gas such as hydrogen (H2) or ammonia (NH3), or a mixed gas of these gases can be used (nitrogen gas in this embodiment).

[0030] On the other hand, a gas exhaust hole 86 for exhausting the gas in the heat treatment space 65 is formed in the lower part of the inner wall of the chamber 6. The gas exhaust hole 86 is formed at a position lower than the recessed portion 62, and may be provided in the reflecting ring 69. The gas exhaust hole 86 is connected to a gas exhaust pipe 88 through a buffer space 87 formed in an annular shape inside the side wall of the chamber 6. The gas exhaust pipe 88 is connected to an exhaust unit 190. A valve 89 is inserted in the middle of the gas exhaust pipe 88. When the valve 89 is opened, the gas in the heat treatment space 65 is exhausted from the gas exhaust hole 86 through the buffer space 87 to the gas exhaust pipe 88. The gas supply hole 81 and the gas exhaust hole 86 may be provided in a plurality of holes along the circumferential direction of the chamber 6, or may be slit-shaped. The process gas supply source 85 and the exhaust unit 190 may be mechanisms provided in the heat treatment apparatus 1, or may be utilities of a factory in which the heat treatment apparatus 1 is installed.

[0031] 2 is a perspective view showing the overall appearance of the holder 7. The holder 7 is configured to include a base ring 71, a connecting portion 72, and a susceptor 74. The base ring 71, the connecting portion 72, and the susceptor 74 are all made of quartz. That is, the entire holder 7 is made of quartz.

[0032] The base ring 71 is an arc-shaped quartz member with a portion missing from the annular shape. This missing portion is provided to prevent interference between the base ring 71 and a transfer arm 11 of the transfer mechanism 10, which will be described later. The base ring 71 is placed on the bottom surface of the recess 62, and is supported by the wall surface of the chamber 6 (see FIG. 1). A plurality of connecting portions 72 (four in this embodiment) are erected on the upper surface of the base ring 71 along the circumferential direction of the annular shape. The connecting portions 72 are also quartz members, and are fixed to the base ring 71 by welding.

[0033] The susceptor 74 is supported by four connecting portions 72 provided on the base ring 71. FIG. 3 is a plan view of the susceptor 74. FIG. 4 is a cross-sectional view of the susceptor 74. The susceptor 74 includes a holding plate 75, a guide ring 76, and a plurality of substrate support pins 77. The holding plate 75 is a substantially circular flat member made of quartz. The diameter of the holding plate 75 is larger than the diameter of the semiconductor wafer W. In other words, the holding plate 75 has a larger planar size than the semiconductor wafer W.

[0034] A guide ring 76 is installed on the periphery of the upper surface of the holding plate 75. The guide ring 76 is an annular member having an inner diameter larger than the diameter of the semiconductor wafer W. For example, when the diameter of the semiconductor wafer W is φ300 mm, the inner diameter of the guide ring 76 is φ320 mm. The inner circumference of the guide ring 76 is a tapered surface that widens from the holding plate 75 upward. The guide ring 76 is made of quartz, similar to the holding plate 75. The guide ring 76 may be fused to the upper surface of the holding plate 75, or may be fixed to the holding plate 75 by a separately processed pin or the like. Alternatively, the holding plate 75 and the guide ring 76 may be processed as an integrated member.

[0035] The area of ​​the upper surface of the holding plate 75 inside the guide ring 76 is a flat holding surface 75a that holds the semiconductor wafer W. A plurality of substrate support pins 77 are provided on the holding surface 75a of the holding plate 75. In this embodiment, a total of 12 substrate support pins 77 are provided at 30° intervals along a circumference concentric with the outer circumferential circle of the holding surface 75a (the inner circumferential circle of the guide ring 76). The diameter of the circle on which the 12 substrate support pins 77 are arranged (the distance between the opposing substrate support pins 77) is smaller than the diameter of the semiconductor wafer W, and is φ270 mm to φ280 mm (φ270 mm in this embodiment) if the diameter of the semiconductor wafer W is φ300 mm. Each substrate support pin 77 is made of quartz. The substrate support pins 77 may be provided on the upper surface of the holding plate 75 by welding, or may be processed integrally with the holding plate 75.

[0036] Returning to FIG. 2, four connecting parts 72 erected on the base ring 71 and the peripheral part of the holding plate 75 of the susceptor 74 are fixed by welding. That is, the susceptor 74 and the base ring 71 are fixedly connected by the connecting parts 72. The base ring 71 of the holding part 7 is supported on the wall surface of the chamber 6, and the holding part 7 is attached to the chamber 6. When the holding part 7 is attached to the chamber 6, the holding plate 75 of the susceptor 74 is in a horizontal position (a position in which the normal line coincides with the vertical direction). That is, the holding surface 75a of the holding plate 75 is a horizontal plane.

[0037] The semiconductor wafer W carried into the chamber 6 is placed and held in a horizontal position on the susceptor 74 of the holder 7 attached to the chamber 6. At this time, the semiconductor wafer W is supported by twelve substrate support pins 77 standing on a holding plate 75 and held on the susceptor 74. More precisely, the upper ends of the twelve substrate support pins 77 contact the lower surface of the semiconductor wafer W to support the semiconductor wafer W. The heights of the twelve substrate support pins 77 (the distance from the upper ends of the substrate support pins 77 to the holding surface 75a of the holding plate 75) are uniform, so that the twelve substrate support pins 77 can support the semiconductor wafer W in a horizontal position.

[0038] Furthermore, the semiconductor wafer W is supported by a plurality of substrate support pins 77 at a predetermined distance from the holding surface 75a of the holding plate 75. The thickness of the guide ring 76 is greater than the height of the substrate support pins 77. Therefore, the guide ring 76 prevents the semiconductor wafer W supported by the plurality of substrate support pins 77 from shifting in the horizontal direction.

[0039] 2 and 3, an opening 78 is formed in the holding plate 75 of the susceptor 74, penetrating vertically. The opening 78 is provided so that the radiation thermometer 20 can receive radiation light (infrared light) emitted from the underside of the semiconductor wafer W. That is, the radiation thermometer 20 receives the light emitted from the underside of the semiconductor wafer W through the opening 78 and a transparent window 21 attached to the through hole 61a of the chamber side part 61, and measures the temperature of the semiconductor wafer W. Furthermore, the holding plate 75 of the susceptor 74 is provided with four through holes 79 through which the lift pins 12 of the transfer mechanism 10, which will be described later, pass to transfer the semiconductor wafer W.

[0040] FIG. 5 is a plan view of the transfer mechanism 10. FIG. 6 is a side view of the transfer mechanism 10. The transfer mechanism 10 includes two transfer arms 11. The transfer arms 11 are formed in an arc shape that is aligned with the generally annular recess 62. Two lift pins 12 are provided upright on each of the transfer arms 11. The transfer arms 11 and the lift pins 12 are made of quartz. Each transfer arm 11 is rotatable by a horizontal movement mechanism 13. The horizontal movement mechanism 13 horizontally moves the pair of transfer arms 11 between a transfer operation position (solid line position in FIG. 5) where the semiconductor wafer W is transferred to the holder 7 and a retracted position (double-dashed line position in FIG. 5) where the pair of transfer arms 11 do not overlap the semiconductor wafer W held by the holder 7 in a plan view. The horizontal movement mechanism 13 may be a mechanism that rotates each transfer arm 11 using an individual motor, or a mechanism that uses a link mechanism to rotate a pair of transfer arms 11 in unison using a single motor.

[0041] The pair of transfer arms 11 are raised and lowered together with the horizontal movement mechanism 13 by the lifting mechanism 14. When the lifting mechanism 14 raises the pair of transfer arms 11 to the transfer operation position, the total of four lift pins 12 pass through the through holes 79 (see FIGS. 2 and 3) formed in the susceptor 74, and the upper ends of the lift pins 12 protrude from the upper surface of the susceptor 74. On the other hand, when the lifting mechanism 14 lowers the pair of transfer arms 11 to the transfer operation position to remove the lift pins 12 from the through holes 79, and the horizontal movement mechanism 13 moves the pair of transfer arms 11 to open them, each transfer arm 11 moves to a retracted position. The retracted position of the pair of transfer arms 11 is directly above the base ring 71 of the holder 7. Since the base ring 71 is placed on the bottom surface of the recess 62, the retracted position of the transfer arms 11 is inside the recess 62. In addition, an exhaust mechanism (not shown) is provided near the location where the drive part of the transfer mechanism 10 (horizontal movement mechanism 13 and lifting mechanism 14) is located, and is configured to exhaust the atmosphere around the drive part of the transfer mechanism 10 to the outside of the chamber 6.

[0042] Returning to FIG. 1, the flash heating unit 5 provided above the chamber 6 is configured to include a light source consisting of multiple (30 in this embodiment) xenon flash lamps FL inside a housing 51, and a reflector 52 provided to cover the light source from above. A lamp light emission window 53 is attached to the bottom of the housing 51 of the flash heating unit 5. The lamp light emission window 53 forming the floor of the flash heating unit 5 is a plate-shaped quartz window made of quartz. By installing the flash heating unit 5 above the chamber 6, the lamp light emission window 53 faces the upper chamber window 63. The flash lamps FL irradiate flash light from above the chamber 6 through the lamp light emission window 53 and the upper chamber window 63 into the heat treatment space 65.

[0043] The multiple flash lamps FL are each a rod-shaped lamp having a long cylindrical shape, and are arranged in a plane such that their respective longitudinal directions are parallel to each other along the main surface of the semiconductor wafer W held by the holder 7 (i.e., along the horizontal direction). Therefore, the plane formed by the arrangement of the flash lamps FL is also a horizontal plane. The area in which the multiple flash lamps FL are arranged is larger than the planar size of the semiconductor wafer W.

[0044] The xenon flash lamp FL comprises a cylindrical glass tube (discharge tube) filled with xenon gas and having an anode and a cathode connected to a capacitor at both ends, and a trigger electrode attached to the outer periphery of the glass tube. Since xenon gas is an electrical insulator, electricity does not flow through the glass tube under normal conditions even if an electric charge is stored in the capacitor. However, when a high voltage is applied to the trigger electrode to break down the insulation, the electricity stored in the capacitor flows instantly through the glass tube, and light is emitted by the excitation of the xenon atoms or molecules at that time. In such a xenon flash lamp FL, the electrostatic energy stored in the capacitor in advance is converted into an extremely short light pulse of 0.1 to 100 milliseconds, so that it has the characteristic of being able to irradiate extremely strong light compared to a light source that is continuously lit such as a halogen lamp HL. In other words, the flash lamp FL is a pulsed light emitting lamp that emits light instantaneously for an extremely short time of less than one second. The light emission time of the flash lamps FL can be adjusted by the coil constant of the lamp power supply that supplies power to the flash lamps FL.

[0045] Moreover, the reflector 52 is provided above the multiple flash lamps FL so as to cover them entirely. The basic function of the reflector 52 is to reflect the flash light emitted from the multiple flash lamps FL toward the heat treatment space 65. The reflector 52 is made of an aluminum alloy plate, and its surface (the surface facing the flash lamps FL) is roughened by blasting.

[0046] The halogen heating unit 4 provided below the chamber 6 has a plurality of halogen lamps HL (40 in this embodiment) built inside the housing 41. The halogen heating unit 4 heats the semiconductor wafer W by irradiating light from the plurality of halogen lamps HL into a heat treatment space 65 from below the chamber 6 through a lower chamber window 64.

[0047] FIG. 7 is a plan view showing the arrangement of a plurality of halogen lamps HL. 40 halogen lamps HL are arranged in two tiers, upper and lower. 20 halogen lamps HL are arranged in the upper tier close to the holder 7, and 20 halogen lamps HL are also arranged in the lower tier farther from the holder 7 than the upper tier. Each halogen lamp HL is a rod-shaped lamp having a long cylindrical shape. The 20 halogen lamps HL in both the upper and lower tiers are arranged so that their longitudinal directions are parallel to each other along the main surface of the semiconductor wafer W held by the holder 7 (i.e., along the horizontal direction). Therefore, the plane formed by the arrangement of the halogen lamps HL in both the upper and lower tiers is a horizontal plane.

[0048] 7, the halogen lamps HL are arranged at a higher density in the region facing the periphery of the semiconductor wafer W held by the holder 7 in both the upper and lower tiers than in the region facing the center of the semiconductor wafer W. That is, in both the upper and lower tiers, the arrangement pitch of the halogen lamps HL is shorter in the periphery of the lamp arrangement than in the center. This makes it possible to irradiate a greater amount of light to the periphery of the semiconductor wafer W, which is prone to temperature drop during heating by light irradiation from the halogen heating unit 4.

[0049] The lamp group consisting of the halogen lamps HL in the upper row and the lamp group consisting of the halogen lamps HL in the lower row are arranged to intersect in a lattice pattern. That is, a total of 40 halogen lamps HL are arranged so that the longitudinal direction of the 20 halogen lamps HL arranged in the upper row and the longitudinal direction of the 20 halogen lamps HL arranged in the lower row are perpendicular to each other.

[0050] The halogen lamp HL is a filament type light source that emits light by passing electricity through a filament disposed inside a glass tube, which becomes incandescent. A gas consisting of an inert gas such as nitrogen or argon with a small amount of halogen elements (iodine, bromine, etc.) is sealed inside the glass tube. By introducing halogen elements, it is possible to set the temperature of the filament at a high temperature while suppressing filament breakage. Therefore, the halogen lamp HL has the characteristics of having a longer life than a normal incandescent light bulb and being able to continuously irradiate strong light. In other words, the halogen lamp HL is a continuous lighting lamp that emits light continuously for at least one second or more. In addition, since the halogen lamp HL is a rod-shaped lamp, it has a long life, and by arranging the halogen lamp HL along the horizontal direction, the radiation efficiency to the semiconductor wafer W above is excellent.

[0051] Also, a reflector 43 is provided below the two-tiered halogen lamps HL within the housing 41 of the halogen heating unit 4 (FIG. 1). The reflector 43 reflects the light emitted from the multiple halogen lamps HL toward the heat treatment space 65.

[0052] The control unit 3 controls the various operating mechanisms provided in the heat treatment device 1. The hardware configuration of the control unit 3 is similar to that of a general computer. That is, the control unit 3 includes a CPU, which is a circuit that performs various arithmetic processing, a ROM, which is a read-only memory that stores basic programs, a RAM, which is a readable and writable memory that stores various information, and a magnetic disk that stores control software, data, and the like. The CPU of the control unit 3 executes a predetermined processing program, and thereby the processing in the heat treatment device 1 proceeds.

[0053] In addition to the above configuration, the heat treatment apparatus 1 is provided with various cooling structures to prevent an excessive temperature rise in the halogen heating unit 4, the flash heating unit 5, and the chamber 6 due to the thermal energy generated from the halogen lamps HL and the flash lamps FL during the heat treatment of the semiconductor wafer W. For example, a water-cooling pipe (not shown) is provided in the wall of the chamber 6. The halogen heating unit 4 and the flash heating unit 5 are also of an air-cooled structure that forms a gas flow inside to remove heat. Air is also supplied to the gap between the upper chamber window 63 and the lamp light emission window 53 to cool the flash heating unit 5 and the upper chamber window 63.

[0054] Next, a description will be given of the processing operation in the heat treatment apparatus 1. First, a description will be given of a typical heat treatment operation for a normal semiconductor wafer (product wafer) W that will become a product. The processing procedure for the semiconductor wafer W described below progresses as the control unit 3 controls each operating mechanism of the heat treatment apparatus 1.

[0055] First, prior to processing of the semiconductor wafer W, the valve 84 for supplying air is opened, and the exhaust valve 89 is also opened to start supplying and exhausting air to and from the chamber 6. When the valve 84 is opened, nitrogen gas is supplied to the heat treatment space 65 from the gas supply hole 81. When the valve 89 is opened, the gas in the chamber 6 is exhausted from the gas exhaust hole 86. As a result, the nitrogen gas supplied from the upper part of the heat treatment space 65 in the chamber 6 flows downward and is exhausted from the lower part of the heat treatment space 65.

[0056] Next, the gate valve 185 is opened to open the transport opening 66, and the semiconductor wafer W to be treated is carried into the heat treatment space 65 in the chamber 6 through the transport opening 66 by a transport robot outside the apparatus. At this time, there is a risk that the atmosphere outside the apparatus may be drawn in with the carrying in of the semiconductor wafer W, but since nitrogen gas is continuously supplied to the chamber 6, the nitrogen gas flows out from the transport opening 66, making it possible to minimize the entrainment of such external atmosphere.

[0057] The semiconductor wafer W carried in by the transport robot advances to a position directly above the holder 7 and stops there. Then, the pair of transfer arms 11 of the transfer mechanism 10 move horizontally from the retreated position to the transfer operation position and rise, causing the lift pins 12 to pass through the through holes 79 and protrude from the upper surface of the holding plate 75 of the susceptor 74 to receive the semiconductor wafer W. At this time, the lift pins 12 rise to a position above the upper ends of the substrate support pins 77.

[0058] After the semiconductor wafer W is placed on the lift pins 12, the transport robot leaves the heat treatment space 65, and the transport opening 66 is closed by the gate valve 185. Then, the pair of transfer arms 11 descend, and the semiconductor wafer W is transferred from the transfer mechanism 10 to the susceptor 74 of the holder 7 and held from below in a horizontal position. The semiconductor wafer W is supported by a plurality of substrate support pins 77 erected on the holding plate 75 and held by the susceptor 74. The semiconductor wafer W is held by the holder 7 with the patterned surface facing up. A predetermined gap is formed between the back surface (the main surface opposite to the front surface) of the semiconductor wafer W supported by the plurality of substrate support pins 77 and the holding surface 75a of the holding plate 75. The pair of transfer arms 11 that descend to below the susceptor 74 are retreated to a retreat position, that is, inside the recess 62, by the horizontal movement mechanism 13.

[0059] After the semiconductor wafer W is held from below in a horizontal position by the susceptor 74 of the holder 7 made of quartz, the 40 halogen lamps HL of the halogen heating unit 4 are turned on all at once to start preheating (assisted heating). Halogen light emitted from the halogen lamps HL passes through the lower chamber window 64 and the susceptor 74, both made of quartz, and is irradiated onto the underside of the semiconductor wafer W. The semiconductor wafer W is preheated by being irradiated with light from the halogen lamps HL, and its temperature rises. Note that the transfer arm 11 of the transfer mechanism 10 is retracted inside the recess 62, and does not interfere with heating by the halogen lamps HL.

[0060] The temperature of the semiconductor wafer W, which is heated by the light irradiation from the halogen lamps HL, is measured by a radiation thermometer 20. The measured temperature of the semiconductor wafer W is transmitted to the control unit 3. The control unit 3 controls the output of the halogen lamps HL while monitoring whether the temperature of the semiconductor wafer W, which is heated by the light irradiation from the halogen lamps HL, has reached a predetermined preheating temperature T1. That is, the control unit 3 feedback-controls the output of the halogen lamps HL based on the value measured by the radiation thermometer 20 so that the temperature of the semiconductor wafer W becomes the preheating temperature T1.

[0061] After the temperature of the semiconductor wafer W reaches the preheating temperature T1, the control unit 3 temporarily maintains the semiconductor wafer W at the preheating temperature T1. Specifically, when the temperature of the semiconductor wafer W measured by the radiation thermometer 20 reaches the preheating temperature T1, the control unit 3 adjusts the output of the halogen lamps HL to maintain the temperature of the semiconductor wafer W at approximately the preheating temperature T1.

[0062] When a predetermined time has elapsed since the temperature of the semiconductor wafer W reached the preheating temperature T1, the flash lamps FL of the flash heating unit 5 irradiate the surface of the semiconductor wafer W held on the susceptor 74 with flash light. At this time, part of the flash light emitted from the flash lamps FL heads directly into the chamber 6, and the other part heads into the chamber 6 after being reflected by the reflector 52, and the semiconductor wafer W is flash-heated by the irradiation of these flash lights.

[0063] Flash heating is performed by irradiating a flash of light (flash of light) from the flash lamps FL, and can raise the surface temperature of the semiconductor wafer W in a short time. That is, the flash of light irradiated from the flash lamps FL is an extremely short and strong flash of light with an irradiation time of about 0.1 to 100 milliseconds, in which electrostatic energy previously stored in a capacitor is converted into an extremely short light pulse. The surface temperature of the semiconductor wafer W flash-heated by the irradiation of the flash light from the flash lamps FL instantaneously rises to a processing temperature T2 of 1000°C or higher and then rapidly drops.

[0064] After the flash heating process is completed, the halogen lamps HL are turned off after a predetermined time has elapsed. This causes the temperature of the semiconductor wafer W to rapidly drop from the preheating temperature T1. The temperature of the semiconductor wafer W during the temperature drop is measured by the radiation thermometer 20, and the measurement result is transmitted to the control unit 3. The control unit 3 monitors whether the temperature of the semiconductor wafer W has dropped to a predetermined temperature based on the measurement result of the radiation thermometer 20. Then, after the temperature of the semiconductor wafer W has dropped to a predetermined temperature or lower, the pair of transfer arms 11 of the transfer mechanism 10 again move horizontally from the retreat position to the transfer operation position and rise, so that the lift pins 12 protrude from the upper surface of the susceptor 74 and receive the semiconductor wafer W after the heat treatment from the susceptor 74. Next, the transfer opening 66 that was closed by the gate valve 185 is opened, and the semiconductor wafer W placed on the lift pins 12 is carried out of the chamber 6 by a transfer robot outside the apparatus, completing the heat treatment of the semiconductor wafer W.

[0065] In the heat treatment apparatus 1, the temperature of the semiconductor wafer W is measured by the radiation thermometer 20, and the output of the halogen lamps HL is controlled based on the measured value. In other words, the radiation thermometer 20 is a sensor for lamp control, and is required to accurately measure the temperature of the semiconductor wafer W. The radiation thermometer 20 is set with the emissivity of the semiconductor wafer W, the temperature of which is to be measured, and if there is an error in the set emissivity, the radiation thermometer 20 cannot accurately measure the temperature of the semiconductor wafer W. For this reason, in this embodiment, the emissivity set in the radiation thermometer 20 is automatically adjusted as follows.

[0066] 8, 9, and 10 are flow charts showing the procedure for adjusting the emissivity set in the radiation thermometer 20. The adjustment of the emissivity is performed, for example, before starting the processing of a lot. As a preparatory work for the emissivity adjustment processing, a measurement wafer equipped with a thermocouple is carried into the chamber 6 and placed on the susceptor 74. The measurement wafer is a silicon disk-shaped substrate similar to a normal semiconductor wafer W, except that a thermocouple is attached. The measurement wafer equipped with a thermocouple cannot be transported by a transport robot, so it is manually carried into the chamber 6 and placed on the susceptor 74.

[0067] After the preparation work is completed, first, initial settings are made for executing the emissivity adjustment process (step S1). In step S1, a recipe is selected and parameters are set. The recipe specifies the processing conditions of the cycle heating when performing the adjustment process. In addition, the parameters set include the initial emissivity to be set in the radiation thermometer 20, the upper and lower limits of the emissivity, the number of cycles of the cycle heating, the temperature deviation for stabilization, a correction coefficient, and sampling timing.

[0068] Next, a dummy process is performed (step S2). In this dummy process, cyclic heating is performed in which a heating process in which the temperature of the measurement wafer is raised and then lowered by irradiation with light from the halogen lamps HL is repeated for the number of cycles of the dummy process set in step S1 (for example, 40 times in this embodiment). The dummy process in step S2 raises the temperature of the structures in the chamber, such as the susceptor 74, to a constant stable temperature. This prevents the temperature fluctuations of the structures in the chamber from affecting the subsequent adjustment process.

[0069] After the dummy process is completed, the first round of emissivity adjustment process is started. In the adjustment process, cyclic heating is performed in which a heating process in which the temperature of the measurement wafer is raised and then lowered by irradiation with light from the halogen lamps HL is repeated for the number of cycles of the adjustment process set in step S1 (for example, three times in this embodiment). Figure 11 is a diagram showing the temperature change of the measurement wafer during cyclic heating in the adjustment process. In this embodiment, three cycles of heating process are performed for one adjustment process. The period of one cycle of heating process is, for example, 60 seconds.

[0070] In each of the three cycles of the heating process, the temperature of the measurement wafer, which has been heated to a constant maximum temperature, is measured by a thermocouple and radiation thermometer 20. The timing of temperature measurement in one cycle is set in step S1. The value measured by the thermocouple is the true temperature of the measurement wafer. The radiation thermometer 20 measures the temperature using the initial emissivity set in step S1. To improve the accuracy of the temperature measurement, the temperature is measured at two locations on the surface of the measurement wafer by the thermocouple. The location for temperature measurement by the radiation thermometer 20 is a location on the measurement wafer facing the opening 78 of the susceptor 74. It is preferable that the measurement location by the radiation thermometer 20 is located in the center of the two measurement locations by the thermocouple.

[0071] First, during the period from time t1 to time t2, temperature measurements are performed in the first cycle using the thermocouple and radiation thermometer 20 (step S3). The average value of the temperature measurements at two locations using the thermocouple is taken as the thermocouple temperature (first measured temperature). The temperature measurement using the radiation thermometer 20 is taken as the radiation temperature (second measured temperature). The thermocouple temperature measured by the thermocouple and the radiation temperature measured by the radiation thermometer 20 are transmitted to the control unit 3.

[0072] Next, the control unit 3 calculates the temperature difference between the thermocouple temperature and the radiation temperature in the first cycle, and determines whether the temperature difference is within a predetermined threshold value (step S4). This threshold value is the stability judgment temperature deviation set as a parameter in step S1, and an appropriate temperature can be set (4°C in this embodiment). If the temperature difference between the thermocouple temperature and the radiation temperature is within the threshold value, the process proceeds to step S5. On the other hand, if the temperature difference exceeds the threshold value, the process proceeds to step S10 and performs emissivity correction, which will be described later.

[0073] In step S5, temperature measurements in the second cycle using the thermocouple and radiation thermometer 20 are performed from time t3 to time t4. Next, the control unit 3 calculates the temperature difference between the thermocouple temperature and the radiation temperature in the second cycle, and determines whether the temperature difference is within a predetermined threshold value (step S6). The threshold value here is the same as the threshold value in the first cycle. If the temperature difference between the thermocouple temperature and the radiation temperature is within the threshold value, the process proceeds to step S7. On the other hand, if the temperature difference exceeds the threshold value, the process proceeds to step S10 and emissivity correction is performed.

[0074] In step S7, temperature measurements in the third cycle using the thermocouple and radiation thermometer 20 are performed from time t5 to time t6. Next, the control unit 3 calculates the temperature difference between the thermocouple temperature and the radiation temperature in the third cycle, and determines whether the temperature difference is within a predetermined threshold value (step S8). The threshold value here is the same as the threshold value in the first cycle. If the temperature difference between the thermocouple temperature and the radiation temperature is within the threshold value, the emissivity adjustment process ends. On the other hand, if the temperature difference exceeds the threshold value, the process proceeds to step S10 to correct the emissivity.

[0075] Steps S3 to S12 are the first emissivity adjustment process. In the first emissivity adjustment process, three cycles of cyclic heating are performed, and the thermocouple temperature, which is the actual temperature of the measurement wafer, is compared with the radiation temperature for each cycle. In the first emissivity adjustment process, if the temperature difference between the thermocouple temperature and the radiation temperature is within a predetermined threshold value in all three cycles of cyclic heating, it is determined that the temperature measurement by the radiation thermometer 20 is accurate, that is, the emissivity set in the radiation thermometer 20 is accurate, and the emissivity adjustment process is terminated. Since the emissivity set in the radiation thermometer 20 is determined to be accurate only when the temperature difference between the thermocouple temperature and the radiation temperature is within a predetermined threshold value in all three cycles of cyclic heating, it is possible to prevent erroneous determination due to measurement error. On the other hand, if the temperature difference between the thermocouple temperature and the radiation temperature exceeds the predetermined threshold value in at least one cycle of the three cycles of cyclic heating, it is determined that there is an error in the emissivity set in the radiation thermometer 20, and the emissivity set in the radiation thermometer 20 is corrected.

[0076] When it is determined in the first round of emissivity adjustment processing that there is an error in the emissivity set in the radiation thermometer 20, if the thermocouple temperature is higher than the radiation temperature, the process proceeds from step S10 to step S11, where the control unit 3 reduces the emissivity set in the radiation thermometer 20. Conversely, if the thermocouple temperature is lower than the radiation temperature, the process proceeds from step S10 to step S12, where the control unit 3 increases the emissivity set in the radiation thermometer 20. The emissivity set in the radiation thermometer 20 is corrected by an amount of change calculated in advance from the correction coefficient set in step S1. Specifically, in steps S11 and S12, the emissivity is corrected at a rate of 0.005 per 4°C of temperature difference between the thermocouple temperature and the radiation temperature. For example, if the thermocouple temperature is 8°C higher than the radiation temperature, the emissivity set in the radiation thermometer 20 is decreased by 0.01. Also, if the thermocouple temperature is 12°C lower than the radiation temperature, the emissivity set in the radiation thermometer 20 is increased by 0.015.

[0077] By correcting the emissivity by the first emissivity adjustment process, a new emissivity is set in the radiation thermometer 20. Then, after the emissivity set in the radiation thermometer 20 is corrected, the second emissivity adjustment process is executed. In the second emissivity adjustment process, as in the first emissivity adjustment process, cyclic heating is executed in which the heating process of raising the temperature of the measurement wafer by irradiating light from the halogen lamp HL and then lowering the temperature is repeated for the number of cycles of the adjustment process set in step S1 (three times in this embodiment). Then, as in the first emissivity adjustment process, the temperature of the measurement wafer, which has been heated to a certain maximum temperature, is measured by the thermocouple and the radiation thermometer 20 for each of the three cycles of the heating process. The radiation thermometer 20 performs temperature measurement using the emissivity corrected by the first emissivity adjustment process.

[0078] In the second emissivity adjustment process, temperature measurement is first performed using the thermocouple and the radiation thermometer 20 in the first cycle of the three cycles (step S13). The thermocouple temperature measured by the thermocouple and the radiation temperature measured by the radiation thermometer 20 are transmitted to the control unit 3. Next, the control unit 3 calculates the temperature difference between the thermocouple temperature and the radiation temperature in the first cycle, and determines whether the temperature difference is within a predetermined threshold value (step S14). This threshold value is the same as the threshold value in the first emissivity adjustment process (4°C in this embodiment). If the temperature difference between the thermocouple temperature and the radiation temperature is within the threshold value, the process proceeds to step S15. On the other hand, if the temperature difference exceeds the threshold value, the process proceeds to step S20 to perform further emissivity correction.

[0079] In step S15, temperature measurements are performed using the thermocouple and radiation thermometer 20 in the second cycle. Next, the control unit 3 calculates the temperature difference between the thermocouple temperature and the radiation temperature in the second cycle, and determines whether the temperature difference is within a predetermined threshold value (step S16). The threshold value here is the same as the threshold value in the first cycle. If the temperature difference between the thermocouple temperature and the radiation temperature is within the threshold value, the process proceeds to step S17. On the other hand, if the temperature difference exceeds the threshold value, the process proceeds to step S20 to perform emissivity correction.

[0080] In step S17, temperature measurements are performed using the thermocouple and radiation thermometer 20 in the third cycle. Next, the control unit 3 calculates the temperature difference between the thermocouple temperature and the radiation temperature in the third cycle, and determines whether the temperature difference is within a predetermined threshold value (step S18). The threshold value here is the same as the threshold value in the first cycle. If the temperature difference between the thermocouple temperature and the radiation temperature is within the threshold value, the emissivity adjustment process ends. On the other hand, if the temperature difference exceeds the threshold value, the process proceeds to step S20 to correct the emissivity.

[0081] Steps S13 to S21 constitute the second round of emissivity adjustment processing. In the second round of emissivity adjustment processing, three cycles of cyclic heating are also performed, and the thermocouple temperature, which is the actual temperature of the measurement wafer, is compared with the radiation temperature for each cycle. In the second round of emissivity adjustment processing, if the temperature difference between the thermocouple temperature and the radiation temperature is within a predetermined threshold value in all three cycles of cyclic heating, it is determined that the emissivity set in the radiation thermometer 20 corrected in the first round of emissivity adjustment processing is accurate, and the emissivity adjustment processing is terminated. On the other hand, if the temperature difference between the thermocouple temperature and the radiation temperature exceeds the predetermined threshold value in at least one cycle of the three cycles of cyclic heating, it is determined that there is an error in the emissivity set in the radiation thermometer 20, and the emissivity set in the radiation thermometer 20 is further corrected.

[0082] If it is determined in the second round of emissivity adjustment processing that there is an error in the emissivity set in the radiation thermometer 20, the control unit 3 calculates the emissivity at which the temperature difference between the thermocouple temperature and the radiation temperature becomes 0 by linear approximation (step S20). Specifically, the control unit 3 obtains a correction line from the temperature difference in the first round of emissivity adjustment processing and the emissivity set in the radiation thermometer 20, and the temperature difference in the second round of emissivity adjustment processing and the emissivity set in the radiation thermometer 20.

[0083] 12 is a diagram showing an example of a correction straight line. The temperature difference ΔT1 is the temperature difference between the thermocouple temperature and the radiation temperature in the first round of emissivity adjustment processing, and the temperature difference ΔT2 is the temperature difference between the thermocouple temperature and the radiation temperature in the second round of emissivity adjustment processing. Furthermore, the emissivity E1 is the emissivity set in the radiation thermometer 20 in the first round of emissivity adjustment processing, and the emissivity E2 is the emissivity set in the radiation thermometer 20 in the second round of emissivity adjustment processing. The control unit 3 obtains the correction straight line by connecting two points in the first round of emissivity adjustment processing and the second round of emissivity adjustment processing with a straight line.

[0084] The control unit 3 obtains, from the acquired correction straight line, the emissivity E3 at which the temperature difference between the thermocouple temperature and the radiation temperature becomes 0. That is, the control unit 3 obtains the emissivity E3 at which the temperature difference between the thermocouple temperature and the radiation temperature becomes 0 based on the results of the first round of emissivity adjustment processing and the results of the second round of emissivity adjustment processing.

[0085] Next, the control unit 3 sets the emissivity E3 in the radiation thermometer 20 such that the temperature difference between the thermocouple temperature and the radiation temperature obtained by linear approximation becomes 0 (step S21). In this way, the emissivity set in the radiation thermometer 20 is corrected in the second round of the emissivity adjustment process.

[0086] Next, after the emissivity set in the radiation thermometer 20 is corrected, a third round of emissivity adjustment processing is performed. In the third round of emissivity adjustment processing, as in the first round of emissivity adjustment processing, cyclic heating is performed in which a heating process in which the temperature of the measurement wafer is raised and then lowered by irradiation with light from the halogen lamps HL is repeated the number of cycles of adjustment processing set in step S1 (three times in this embodiment). Then, as in the first round of emissivity adjustment processing, the temperature of the measurement wafer, which has been raised to a certain maximum temperature, is measured by a thermocouple and radiation thermometer 20 for each of the three cycles of heating processing. The radiation thermometer 20 performs temperature measurement using the emissivity corrected by the second round of emissivity adjustment processing.

[0087] In the third round of emissivity adjustment processing, first, temperature measurement is performed by the thermocouple and the radiation thermometer 20 in the first cycle of the three cycles (step S22). The thermocouple temperature measured by the thermocouple and the radiation temperature measured by the radiation thermometer 20 are transmitted to the control unit 3. Next, the control unit 3 calculates the temperature difference between the thermocouple temperature and the radiation temperature in the first cycle, and determines whether the temperature difference is within a predetermined threshold value (step S23). This threshold value is the same as the threshold value in the first round of emissivity adjustment processing (4°C in this embodiment). If the temperature difference between the thermocouple temperature and the radiation temperature is within the threshold value, the process proceeds to step S24. On the other hand, if the temperature difference exceeds the threshold value, the process returns to step S20 and further emissivity correction is performed.

[0088] In step S24, temperature measurements are performed using the thermocouple and radiation thermometer 20 in the second cycle. Next, the control unit 3 calculates the temperature difference between the thermocouple temperature and the radiation temperature in the second cycle, and determines whether the temperature difference is within a predetermined threshold value (step S25). The threshold value here is the same as the threshold value in the first cycle. If the temperature difference between the thermocouple temperature and the radiation temperature is within the threshold value, the process proceeds to step S26. On the other hand, if the temperature difference exceeds the threshold value, the process returns to step S20 and the emissivity is corrected.

[0089] In step S26, temperature measurements are performed using the thermocouple and radiation thermometer 20 in the third cycle. Next, the control unit 3 calculates the temperature difference between the thermocouple temperature and the radiation temperature in the third cycle, and determines whether the temperature difference is within a predetermined threshold value (step S27). The threshold value here is the same as the threshold value in the first cycle. If the temperature difference between the thermocouple temperature and the radiation temperature is within the threshold value, the emissivity adjustment process ends. On the other hand, if the temperature difference exceeds the threshold value, the process returns to step S20 and the emissivity is corrected.

[0090] In the third emissivity adjustment process, three cycles of cyclic heating are also performed, and the thermocouple temperature, which is the actual temperature of the measurement wafer, is compared with the radiation temperature for each cycle. In the third emissivity adjustment process, if the temperature difference between the thermocouple temperature and the radiation temperature is within a predetermined threshold value in all three cycles of cyclic heating, it is determined that the emissivity set in the radiation thermometer 20 corrected in the second emissivity adjustment process is accurate, and the emissivity adjustment process is terminated. On the other hand, if the temperature difference between the thermocouple temperature and the radiation temperature exceeds the predetermined threshold value in at least one cycle of the three cycles of cyclic heating, it is determined that there is an error in the emissivity set in the radiation thermometer 20, and the emissivity set in the radiation thermometer 20 is further corrected.

[0091] If it is determined in the third round of emissivity adjustment processing that there is an error in the emissivity set in the radiation thermometer 20, the emissivity correction processing in steps S20 and S21 is executed again. Then, after the emissivity set in the radiation thermometer 20 is corrected, the processing from steps S22 to S27 is executed again. That is, the processing from steps S20 to S27 is repeated until the temperature difference between the thermocouple temperature and the radiation temperature falls within a predetermined threshold value in all three cycles of cyclic heating.

[0092] Incidentally, when the emissivity set in the radiation thermometer 20 is corrected in each round of the emissivity adjustment process, the corrected emissivity may be greater than the upper limit value of the emissivity set in step S1 or less than the lower limit value. When the emissivity of the radiation thermometer 20 exceeds the preset upper limit value or lower limit value, the emissivity is clearly at an abnormal value. For this reason, when the corrected emissivity is greater than the upper limit value of the emissivity set in step S1 or less than the lower limit value, the control unit 3 issues an alarm and ends the emissivity adjustment process.

[0093] Furthermore, if the slope of the correction line acquired in step S20 is 0, that is, if the temperature difference ΔT1 in the first round of emissivity adjustment processing and the temperature difference ΔT2 in the second round of emissivity adjustment processing are the same value, the adjustment processing is also abnormal. Therefore, in such a case as well, the control unit 3 issues an alarm and ends the emissivity adjustment processing.

[0094] In this embodiment, while the measurement wafer is subjected to a cyclic heating process, the temperature of the heated measurement wafer is measured by a thermocouple and radiation thermometer 20. Then, the emissivity set in radiation thermometer 20 is corrected based on the temperature difference between the true temperature of the measurement wafer measured by the thermocouple and the temperature measured by radiation thermometer 20. Therefore, the emissivity set in radiation thermometer 20 can be adjusted with high accuracy.

[0095] In addition, since the emissivity set in the radiation thermometer 20 can be automatically adjusted, no manual labor is required, and the operator of the heat treatment device 1 can adjust the emissivity while performing other tasks.

[0096] Although the embodiment of the present invention has been described above, this invention can be modified in various ways without departing from the spirit of the invention. For example, in the above embodiment, the measurement wafer is subjected to cycle heating while the emissivity is adjusted, but this is not limited to this. The measurement wafer may be continuously heated to a constant temperature by light irradiation from a halogen lamp HL, the temperature of the measurement wafer may be measured by a thermocouple and a radiation thermometer 20, and the emissivity set in the radiation thermometer 20 may be corrected based on the temperature difference.

[0097] Also, a preliminary correction of the emissivity set in the radiation thermometer 20 may be performed during the dummy processing in step S2. Specifically, for example, when the temperature of the measurement wafer measured by the thermocouple differs from the temperature of the measurement wafer measured by the radiation thermometer 20 at the time when half the number of cycles of the dummy processing is completed (at the time when 20 cycles are completed in the above embodiment), the emissivity set in the radiation thermometer 20 is preliminary corrected. In this preliminary correction, the same correction as in steps S10 to S12 is performed. That is, when the temperature of the measurement wafer measured by the thermocouple is higher than the temperature of the measurement wafer measured by the radiation thermometer 20, the emissivity set in the radiation thermometer 20 is decreased at a rate of 0.005 per 4°C of temperature difference. Conversely, when the temperature of the measurement wafer measured by the thermocouple is lower than the temperature of the measurement wafer measured by the radiation thermometer 20, the emissivity set in the radiation thermometer 20 is increased at a rate of 0.005 per 4°C of temperature difference.

[0098] By carrying out such preliminary correction so that the emissivity set in radiation thermometer 20 approaches an accurate value in advance, it becomes possible to complete the emissivity adjustment process in a short time. In particular, when the temperature of the measurement wafer measured by the thermocouple is higher than the temperature of the measurement wafer measured by radiation thermometer 20, the thermocouple temperature and the radiation temperature are unlikely to approach each other in the subsequent adjustment process, so preliminary correction is effective.

[0099] Furthermore, the threshold value for determining the temperature difference between the thermocouple temperature and the radiation temperature and the correction coefficient for correcting the emissivity are not limited to the examples in the above embodiment, and any value can be set in step S1.

[0100] In the above embodiment, the flash heating unit 5 is provided with 30 flash lamps FL, but this is not limited to this and the number of flash lamps FL can be any number. The flash lamps FL are not limited to xenon flash lamps and may be krypton flash lamps. The number of halogen lamps HL provided in the halogen heating unit 4 is not limited to 40 and can be any number.

[0101] In the above embodiment, the semiconductor wafer W is preheated using a filament-type halogen lamp HL as a continuously lit lamp that emits light continuously for one second or more. However, this is not limited to this, and preheating may be performed using a discharge-type arc lamp (e.g., a xenon arc lamp) as a continuously lit lamp instead of the halogen lamp HL.

[0102] Furthermore, the substrate to be processed by the heat treatment apparatus 1 is not limited to a semiconductor wafer, but may be a glass substrate used in a flat panel display such as a liquid crystal display device, or a substrate for a solar cell. [Explanation of symbols]

[0103] 1 Heat treatment equipment 3. Control Unit 4 Halogen heating section 5 Flash heating section 6 Chambers 7 Holding part 10 Transfer mechanism 20 Radiation thermometer 65 Heat Treatment Space 74 Susceptor 75 Retaining Plate 78 Opening 77 Board support pin FL Flash lamp HL Halogen Lamp W Semiconductor wafer

Claims

1. 1. An emissivity adjustment method for adjusting an emissivity set in a radiation thermometer installed in a heat treatment device, comprising: a carrying step of carrying a substrate having a thermocouple attached thereto into a chamber; a dummy treatment step of repeating a first cycle of a heat treatment in which the temperature of the substrate is increased and then decreased by irradiation with light from a continuously lit lamp; a first adjustment step of repeating a heat treatment in which the temperature of the substrate is increased and then decreased by irradiation with light from the continuously lit lamp a second number of cycles; Equipped with the first adjusting step includes a first comparing step of comparing a first measured temperature obtained by measuring the temperature of the heated substrate by the thermocouple with a second measured temperature obtained by measuring the temperature of the substrate by the radiation thermometer for each cycle; the first adjustment step terminates the adjustment of the emissivity set in the radiation thermometer when a temperature difference between the first measured temperature and the second measured temperature is within a predetermined threshold value in all cycles of the second cycle number, and corrects the emissivity set in the radiation thermometer when a temperature difference between the first measured temperature and the second measured temperature exceeds the threshold value in at least one cycle of the second cycle number.

2. The emissivity adjusting method according to claim 1, a temperature difference between the first measured temperature and the second measured temperature exceeding the threshold value, the temperature difference being determined by the temperature difference between the first measured temperature and the second measured temperature, and the temperature difference being determined by the temperature difference between the first measured temperature and the second measured temperature exceeding the threshold value.

3. The emissivity adjusting method according to claim 2, The emissivity adjustment method according to claim 1, wherein in the first adjustment step, when the first measured temperature is higher than the second measured temperature, the emissivity set in the radiation thermometer is reduced.

4. The emissivity adjusting method according to claim 3, a second adjustment step of repeating a heat treatment in which the temperature of the substrate is increased and then decreased by irradiation with light from the continuously lit lamp by the second cycle number after correcting the emissivity set in the radiation thermometer in the first adjustment step, the second adjusting step includes a second comparing step of comparing the first measured temperature with the second measured temperature for each cycle; the second adjustment step terminates the adjustment of the emissivity set in the radiation thermometer when a temperature difference between the first measured temperature and the second measured temperature is within the threshold value in all cycles of the second cycle number, and further corrects the emissivity set in the radiation thermometer when a temperature difference between the first measured temperature and the second measured temperature exceeds the threshold value in at least one cycle of the second cycle number.

5. The emissivity adjusting method according to claim 4, an emissivity adjustment method, characterized in that, in the second adjustment step, when the temperature difference between the first measured temperature and the second measured temperature exceeds the threshold value, the radiation thermometer is set to an emissivity at which the temperature difference between the first measured temperature and the second measured temperature becomes 0, the emissivity being obtained by linear approximation based on the temperature difference between the first measured temperature and the second measured temperature in the first comparison step and the temperature difference between the first measured temperature and the second measured temperature in the second comparison step.

6. 6. The emissivity adjusting method according to claim 5, an emissivity adjustment method, characterized in that an alarm is issued when a temperature difference between the first measured temperature and the second measured temperature in the first comparison step and a temperature difference between the first measured temperature and the second measured temperature in the second comparison step are the same value.

7. 7. The emissivity adjusting method according to claim 6, an emissivity adjustment method comprising the steps of: issuing an alarm when the emissivity set in the radiation thermometer corrected in the first adjustment step or the second adjustment step becomes greater than a predetermined upper limit value or becomes less than a predetermined lower limit value.

8. The emissivity adjusting method according to any one of claims 1 to 7, a temperature sensor for detecting a temperature of the substrate measured by the thermocouple during the dummy processing step and a temperature sensor for detecting a temperature of the substrate measured by the radiation thermometer, the temperature sensor comprising: a first sensor for detecting a temperature of the substrate measured by the radiation thermometer;

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