Temperature measurement method and heat treatment system

Abstract

To provide a temperature measurement method and a heat treatment system with which it is possible to accurately measure the surface temperature of substrates during flash light irradiation.SOLUTION: A semiconductor wafer surface having been preliminarily heated by light irradiation from a halogen lamp is irradiated with flash light from a flash lamp to heat the surface. The behavior of the semiconductor wafer that is rapidly deformed at flash light irradiation time is imaged by a high-speed camera at prescribed intervals to acquire a plurality of images. An angle calculation unit carries out image processing on the plurality of images and calculates a measurement angle of an upper radiation thermometer and the semiconductor wafer for each prescribed interval. An emissivity calculation unit obtains an apparent emissivity of the semiconductor wafer from the upper radiation thermometer for each prescribed interval on the basis of the measurement angle. Furthermore, a temperature correction unit corrects the temperature of the semiconductor wafer having been measured by the upper radiation thermometer for each prescribed interval, on the basis of the obtained emissivity.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a temperature measurement method and a heat treatment system for measuring the temperature of a substrate that changes due to flash light irradiation. The substrate to be treated includes, for example, a semiconductor wafer, a substrate for a liquid crystal display device, a substrate for a flat panel display (FPD), a substrate for an optical disk, a substrate for a magnetic disk, or a substrate for a solar cell. [Background technology]

[0002] Flash lamp annealing (FLA), which heats semiconductor wafers in an extremely short time, is attracting attention in the semiconductor device manufacturing process.Flash lamp annealing is a heat treatment technology that uses a xenon flash lamp (hereinafter, simply referred to as "flash lamp" means a xenon flash lamp) to irradiate the surface of a semiconductor wafer with flash light, thereby raising the temperature of only the surface of the semiconductor wafer in an extremely short time (a few milliseconds or less).

[0003] The spectral distribution of radiation from a xenon flash lamp is in the ultraviolet to near-infrared range, with a shorter wavelength than conventional halogen lamps and a wavelength that roughly matches the fundamental absorption band of silicon semiconductor wafers. Therefore, when a semiconductor wafer is irradiated with flash light from a xenon flash lamp, little light is transmitted, making it possible to rapidly heat the semiconductor wafer. It has also been found that if the flash light is irradiated for an extremely short period of time, less than a few milliseconds, it is possible to selectively heat only the area near the surface of the semiconductor wafer.

[0004] Flash lamp annealing is used in processes that require heating for an extremely short period of time, such as activating impurities implanted in a semiconductor wafer. By irradiating the surface of a semiconductor wafer into which impurities have been implanted by ion implantation with a flash light from a flash lamp, the surface of the semiconductor wafer can be heated to the activation temperature in an extremely short period of time, allowing only the impurities to be activated without diffusing them deeply.

[0005] Wafer temperature management is important in any heat treatment of semiconductor wafers, not just flash lamp annealing. In particular, with flash lamp annealing, the temperature of only the surface vicinity of the semiconductor wafer is selectively raised, making it important to measure the surface temperature of the semiconductor wafer, which changes rapidly when irradiated with flash light. Since the device characteristics of a semiconductor wafer after flash light irradiation are determined by the maximum temperature (peak temperature) reached on the wafer surface during flash light irradiation, it is necessary to measure at least this maximum temperature. Patent Document 1 discloses a technique for accurately determining the emissivity of the surface of a semiconductor wafer and measuring the surface temperature of the semiconductor wafer during flash light irradiation using a radiation thermometer. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2017-9450 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, in flash lamp annealing, the surface of a semiconductor wafer is instantaneously irradiated with extremely high-energy flash light, which causes a rapid rise in the surface temperature of the semiconductor wafer while the backside temperature does not rise significantly, resulting in a temperature gradient from the front to the backside. This causes sudden thermal expansion only near the front side of the semiconductor wafer, causing the semiconductor wafer to deform rapidly, warping with the top surface becoming convex. As a result, vibration of the semiconductor wafer on the susceptor supporting it has also been observed. Even if the emissivity of the surface of a semiconductor wafer is accurately determined using the technology disclosed in Patent Document 1, deformation of the semiconductor wafer, the target of temperature measurement, causes fluctuations in the apparent emissivity as seen by the radiation thermometer, making it difficult to accurately measure the surface temperature of the semiconductor wafer when irradiated with flash light. Furthermore, the warpage of the semiconductor wafer is not constant from process to process, which also reduces the reproducibility of temperature measurements.

[0008] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a temperature measurement method and a heat treatment system that can accurately measure the temperature of a substrate when irradiated with flash light. [Means for solving the problem]

[0009] In order to solve the above problem, the invention of claim 1 is a temperature measurement method for measuring the temperature of a substrate that changes due to flash light irradiation, comprising: an irradiation step of irradiating a surface of the substrate with flash light from a flash lamp; an angle calculation step of calculating a measurement angle between a radiation thermometer and the substrate when the substrate is deformed by the irradiation of the flash light; an emissivity calculation step of calculating the emissivity of the substrate as seen from the radiation thermometer based on the measurement angle calculated in the angle calculation step; and a correction step of correcting the temperature of the substrate measured by the radiation thermometer based on the emissivity calculated in the emissivity calculation step.

[0010] Furthermore, the invention of claim 2 is characterized in that in the temperature measurement method according to the invention of claim 1, the angle calculation process calculates the measurement angle from a binary image obtained by binarizing an image of the substrate captured by a camera when irradiated with flash light.

[0011] Furthermore, the invention of claim 3 is characterized in that, in the temperature measurement method according to the invention of claim 2, in the angle calculation step, the camera takes images of the substrate at predetermined intervals, in the emissivity calculation step, the emissivity is calculated at the predetermined intervals, and in the correction step, the temperature of the substrate is corrected at the predetermined intervals.

[0012] Furthermore, the invention of claim 4 is characterized in that in the temperature measurement method according to the invention of claim 1, in the emissivity calculation step, the emissivity is calculated from a table showing the correlation between measurement angle and emissivity.

[0013] Furthermore, the invention of claim 5 is characterized in that in the temperature measurement method according to the invention of claim 1, the angle calculation step calculates the measurement angle based on the warpage state of the substrate obtained from a simulation in which processing conditions are set as input parameters for a model.

[0014] The invention of claim 6 is a heat treatment system for heating a substrate by irradiating the substrate with flash light, comprising: a chamber for accommodating a substrate; a holder for holding the substrate in the chamber; a flash lamp for irradiating flash light onto the substrate held by the holder; a radiation thermometer for measuring the temperature of the substrate; an angle calculation unit for calculating a measurement angle between the radiation thermometer and the substrate when the substrate is deformed by the irradiation of the flash light; an emissivity calculation unit for calculating the emissivity of the substrate as seen from the radiation thermometer based on the measurement angle calculated by the angle calculation unit; and a temperature correction unit for correcting the temperature of the substrate measured by the radiation thermometer based on the emissivity calculated by the emissivity calculation unit.

[0015] Furthermore, the invention of claim 7 is characterized in that, in the heat treatment system according to the invention of claim 6, the system further comprises a camera that images the substrate held by the holding unit, and the angle calculation unit calculates the measurement angle from a binary image obtained by binarizing an image of the substrate captured by the camera when irradiated with flash light.

[0016] Furthermore, the invention of claim 8 is characterized in that, in the heat treatment system according to the invention of claim 7, the camera takes images of the substrate at predetermined intervals when irradiated with flash light, the emissivity calculation unit calculates the emissivity at the predetermined intervals, and the temperature correction unit corrects the temperature of the substrate at the predetermined intervals.

[0017] Furthermore, the invention of claim 9 is characterized in that, in the heat treatment system of the invention of claim 6, it further comprises a memory unit that stores a table showing the correlation between the measurement angle and the emissivity, and the emissivity calculation unit calculates the emissivity from the table.

[0018] Furthermore, the invention of claim 10 is characterized in that, in the heat treatment system according to the invention of claim 6, the angle calculation unit calculates the measurement angle based on the warpage state of the substrate obtained from a simulation in which processing conditions are set as input parameters for a model. [Effects of the Invention]

[0019] According to the inventions of claims 1 to 5, the temperature of the substrate measured by the radiation thermometer is corrected based on the emissivity corresponding to the measurement angle between the radiation thermometer and the substrate, so the measured temperature of the substrate is corrected based on the emissivity corresponding to the measurement angle depending on the warpage state of the substrate, and the temperature of the substrate when irradiated with flash light can be measured accurately.

[0020] According to the inventions of claims 6 to 10, the temperature of the substrate measured by the radiation thermometer is corrected based on the emissivity corresponding to the measurement angle between the radiation thermometer and the substrate, so the measured temperature of the substrate is corrected based on the emissivity corresponding to the measurement angle depending on the warpage state of the substrate, and the temperature of the substrate when irradiated with flash light can be measured accurately. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a vertical cross-sectional view showing the configuration of a heat treatment apparatus for carrying out a temperature measuring method according to the present invention. [Figure 2] FIG. 2 is a perspective view showing the overall appearance of the holding portion. [Figure 3] FIG. [Figure 4] FIG. 2 is a cross-sectional view of a susceptor. [Figure 5] FIG. [Figure 6] FIG. [Figure 7] FIG. 2 is a plan view showing the arrangement of a plurality of halogen lamps. [Figure 8] FIG. 2 is a block diagram showing the configuration of a control unit. [Figure 9] 2 is a flowchart showing a procedure of a processing operation in the heat treatment apparatus of FIG. [Figure 10] FIG. 10 is a diagram showing the measurement angle between the upper radiation thermometer and the semiconductor wafer. [Figure 11] FIG. 10 is a diagram showing an example of a table defining the correlation between measurement angle and emissivity. [Figure 12] FIG. 1 is a diagram showing an example of photographing a semiconductor wafer using two high-speed cameras. [Figure 13] FIG. 10 is a diagram illustrating an example of a process for determining a warpage state using a simulation. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Hereinafter, expressions indicating relative or absolute positional relationships (e.g., "in one direction," "along one direction," "parallel," "orthogonal," "center," "concentric," "coaxial," etc.) not only strictly represent the positional relationship but also represent a state of relative angular or distance displacement within a tolerance or a range that provides equivalent functionality, unless otherwise specified. Furthermore, expressions indicating an equal state (e.g., "identical," "equal," "homogeneous," etc.) not only represent a state of strict quantitative equality but also represent a state of difference that provides a tolerance or equivalent functionality, unless otherwise specified. Furthermore, expressions indicating a shape (e.g., "circular," "square," "cylindrical," etc.) not only represent a geometrically strict shape but also represent a shape within a range that provides equivalent functionality, such as irregularities or chamfers, unless otherwise specified. Furthermore, expressions such as "comprise," "comprise," "include," "have," etc., regarding components, are not exclusive expressions that exclude the presence of other components. Furthermore, the expression "at least one of A, B, and C" includes "A only," "B only," "C only," "any two of A, B, and C," and "all of A, B, and C."

[0023] FIG. 1 is a longitudinal cross-sectional view showing the configuration of a heat treatment apparatus 1 for carrying out a temperature measurement method according to the present invention. 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 may be, for example, φ300 mm or φ450 mm (φ300 mm in this embodiment). Note that in FIG. 1 and the subsequent figures, the dimensions and number of various parts are exaggerated or simplified as necessary for ease of understanding.

[0024] Heat treatment apparatus 1 includes a chamber 6 that accommodates a semiconductor wafer W, a flash heating unit 5 that incorporates multiple flash lamps FL, and a halogen heating unit 4 that incorporates multiple halogen lamps HL. The flash heating unit 5 is provided above chamber 6, and the halogen heating unit 4 is provided below. Heat treatment apparatus 1 also includes, inside chamber 6, a holder 7 that holds the semiconductor wafer W in a horizontal position, and a transfer mechanism 10 that transfers the semiconductor wafer W between the holder 7 and the outside of the apparatus. Heat treatment apparatus 1 also includes a control unit 3 that controls the operating mechanisms provided in the halogen heating unit 4, flash heating unit 5, and chamber 6 to perform heat treatment on the semiconductor wafer W.

[0025] The chamber 6 is constructed by attaching quartz chamber windows to 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 attached to and closing the upper opening, and a lower chamber window 64 attached to and closing the lower opening. The upper chamber window 63, which forms the ceiling of the chamber 6, is a disc-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, which forms the floor of the chamber 6, is also a disc-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.

[0026] Furthermore, a reflective ring 68 is attached to the upper part of the inner wall surface of the chamber side 61, and a reflective ring 69 is attached to the lower part. Both 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 61. On the other hand, the lower reflective ring 69 is attached by fitting it from the lower side of the chamber side 61 and fastening it with screws (not shown). In other words, both reflective rings 68, 69 are detachably attached to the chamber side 61. The internal space of the chamber 6, i.e., the space surrounded by the upper chamber window 63, the lower chamber window 64, the chamber side 61, and the reflective rings 68, 69, is defined as a heat treatment space 65.

[0027] By attaching the reflecting rings 68, 69 to 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 attached, 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 made of a metal material (e.g., stainless steel) that has excellent strength and heat resistance.

[0028] Furthermore, a transfer opening (furnace port) 66 is formed in the chamber side portion 61, through which a semiconductor wafer W is loaded into and unloaded from the chamber 6. The transfer opening 66 can be opened and closed by a gate valve 185. The transfer opening 66 is connected to the outer peripheral surface of the recessed portion 62. Therefore, when the gate valve 185 opens the transfer opening 66, the semiconductor wafer W can be loaded into and unloaded from the heat treatment space 65 through the transfer opening 66 and the recessed portion 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.

[0029] Furthermore, through holes 61a and 61b are formed in the chamber side portion 61. The through hole 61a is a cylindrical hole for guiding infrared light radiated from the upper surface of a semiconductor wafer W held on a susceptor 74 (described later) to the infrared sensor 29 of the upper radiation thermometer 25. On the other hand, the through hole 61b is a cylindrical hole for guiding infrared light radiated from the lower surface of the semiconductor wafer W to the infrared sensor 24 of the lower radiation thermometer 20. The through holes 61a and 61b are provided at an angle with respect to the horizontal direction so that their axes of penetration intersect with the main surface of the semiconductor wafer W held on the susceptor 74. A transparent window 26 made of calcium fluoride material that transmits infrared light in a wavelength range measurable by the upper radiation thermometer 25 is attached to the end of the through hole 61a facing the heat treatment space 65. Furthermore, a transparent window 21 made of barium fluoride material that transmits infrared light in the wavelength range that can be measured by the lower radiation thermometer 20 is attached to the end of the through hole 61b facing the heat treatment space 65.

[0030] Gas supply holes 81 are formed in the upper part of the inner wall of the chamber 6 to supply processing gas to the heat treatment space 65. The gas supply holes 81 are formed at a position above the recess 62 and may be provided in the reflecting ring 68. The gas supply holes 81 are connected to a gas supply pipe 83 via 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 gas supply pipe 83. When the valve 84 is opened, 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 spreads within the buffer space 82, which has lower fluid resistance than the gas supply holes 81, and is supplied from the gas supply holes 81 into the heat treatment space 65. The processing gas may be, for example, an inert gas such as nitrogen (N), a reactive gas such as hydrogen (H) or ammonia (NH), or a mixture thereof (nitrogen gas in this embodiment).

[0031] Meanwhile, a gas exhaust hole 86 is formed in the lower part of the inner wall of the chamber 6 to exhaust gas from the heat treatment space 65. The gas exhaust hole 86 is formed below the recess 62 and may be provided in the reflecting ring 69. The gas exhaust hole 86 is connected to a gas exhaust pipe 88 via 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 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 multiple numbers 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 where the heat treatment apparatus 1 is installed.

[0032] A gas exhaust pipe 191 for discharging gas from the heat treatment space 65 is also connected to the tip of the transfer opening 66. The gas exhaust pipe 191 is connected to an exhaust unit 190 via a valve 192. By opening the valve 192, the gas in the chamber 6 is exhausted through the transfer opening 66.

[0033] 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. In other words, the entire holder 7 is made of quartz.

[0034] 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.

[0035] 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. That is, the holding plate 75 has a planar size larger than that of the semiconductor wafer W.

[0036] 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, if the diameter of the semiconductor wafer W is φ300 mm, the inner diameter of the guide ring 76 is φ320 mm. The inner periphery of the guide ring 76 has a tapered surface that widens upward from the holding plate 75. The guide ring 76 is made of quartz, the same as the holding plate 75. The guide ring 76 may be welded 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.

[0037] The area of the upper surface of the holding plate 75 that is 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 opposing substrate support pins 77) is smaller than the diameter of the semiconductor wafer W. If the diameter of the semiconductor wafer W is 300 mm, the diameter is 270 mm to 280 mm (270 mm in this embodiment). Each substrate support pin 77 is made of quartz. The plurality of substrate support pins 77 may be provided on the upper surface of the holding plate 75 by welding, or may be machined integrally with the holding plate 75.

[0038] Returning to FIG. 2, four connecting portions 72 erected on the base ring 71 are fixed to the peripheral edge of the holding plate 75 of the susceptor 74 by welding. That is, the susceptor 74 and the base ring 71 are fixedly connected by the connecting portions 72. The base ring 71 of the holding portion 7 is supported on the wall surface of the chamber 6, and the holding portion 7 is thereby attached to the chamber 6. When the holding portion 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.

[0039] 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 erected 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 underside 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 the twelve substrate support pins 77 can support the semiconductor wafer W in a horizontal position.

[0040] 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.

[0041] 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 lower radiation thermometer 20 can receive radiation (infrared light) emitted from the underside of the semiconductor wafer W. That is, the lower 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 61b of the chamber side 61, thereby measuring the temperature of the semiconductor wafer W. Furthermore, the holding plate 75 of the susceptor 74 is formed with four through-holes 79 through which lift pins 12 of the transfer mechanism 10, which will be described later, pass to transfer the semiconductor wafer W.

[0042] 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 arc-shaped so as to fit the generally annular recess 62. Two lift pins 12 are provided 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 (position indicated by a solid line in FIG. 5) where the transfer arms 11 transfer the semiconductor wafer W to the holder 7 and a retracted position (position indicated by a two-dot chain line in FIG. 5) where the 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 one that rotates each transfer arm 11 using an individual motor, or one that uses a link mechanism to rotate a pair of transfer arms 11 in conjunction with one another using a single motor.

[0043] Furthermore, 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, a total of four lift pins 12 pass through 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 so as to open, 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. Because 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 also 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.

[0044] Returning to FIG. 1 , the flash heating unit 5, which is provided above the chamber 6, is configured with a light source made up 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, which forms 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 a heat treatment space 65 with flash light from above the chamber 6 through the lamp light emission window 53 and the upper chamber window 63.

[0045] The multiple flash lamps FL are each a rod-shaped lamp having a long cylindrical shape, and are arranged in a plane 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 flash lamps FL is also a horizontal plane.

[0046] A xenon flash lamp FL comprises a rod-shaped glass tube (discharge tube) filled with xenon gas and equipped with an anode and cathode connected to a capacitor at both ends, and a trigger electrode attached to the outer surface of the glass tube. Because xenon gas is an electrical insulator, electricity does not flow through the glass tube under normal conditions, even if a charge is stored in the capacitor. However, when a high voltage is applied to the trigger electrode, the insulation is broken down, and the electricity stored in the capacitor flows instantaneously through the glass tube, exciting the xenon atoms or molecules and emitting light. Such a xenon flash lamp FL converts electrostatic energy previously stored in the capacitor into extremely short light pulses of 0.1 to 100 milliseconds, thereby enabling it to emit much stronger light than continuous light sources such as halogen lamps HL. In other words, the flash lamp FL is a pulsed lamp that emits light instantaneously for an extremely short period of time, less than one second. The light-emitting duration of the flash lamp FL can be adjusted by adjusting the coil constant of the lamp power supply that supplies power to the flash lamp FL.

[0047] Furthermore, reflector 52 is provided above the multiple flash lamps FL so as to cover them entirely. The basic function of reflector 52 is to reflect the flash light emitted from the multiple flash lamps FL toward the heat treatment space 65. Reflector 52 is made of an aluminum alloy plate, and its surface (the surface facing the flash lamps FL) is roughened by blasting.

[0048] The halogen heating unit 4, which is provided below the chamber 6, has a plurality of halogen lamps HL (40 in this embodiment) built into the inside of the housing 41. The halogen heating unit 4 heats the semiconductor wafer W by irradiating light from the plurality of halogen lamps HL from below the chamber 6 through a lower chamber window 64 into a heat treatment space 65.

[0049] FIG. 7 is a plan view showing the arrangement of multiple halogen lamps HL. 40 halogen lamps HL are arranged in two rows, upper and lower. 20 halogen lamps HL are arranged in the upper row, which is closer to the holder 7, and 20 halogen lamps HL are also arranged in the lower row, which is farther from the holder 7 than the upper row. Each halogen lamp HL is a rod-shaped lamp having a long cylindrical shape. In both the upper and lower rows, the 20 halogen lamps HL 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 rows is a horizontal plane.

[0050] 7, the halogen lamps HL are arranged more densely in the region facing the periphery of the semiconductor wafer W held by the holder 7 on both the upper and lower tiers than in the region facing the center of the semiconductor wafer W. That is, on both the upper and lower tiers, the halogen lamps HL are arranged at a shorter pitch in the periphery of the lamp arrangement than in the center. This allows a greater amount of light to be irradiated onto the periphery of the semiconductor wafer W, which is prone to temperature drop during heating due to light irradiation from the halogen heating unit 4.

[0051] The lamp group consisting of the halogen lamps HL on the upper row and the lamp group consisting of the halogen lamps HL on the lower row are arranged so as to intersect in a grid pattern. That is, a total of 40 halogen lamps HL are arranged so that the longitudinal direction of the 20 halogen lamps HL arranged on the upper row and the longitudinal direction of the 20 halogen lamps HL arranged on the lower row are perpendicular to each other.

[0052] A halogen lamp HL is a filament-type light source that emits light by passing electricity through a filament placed inside a glass tube, causing it to incandescent. The glass tube is filled with an inert gas, such as nitrogen or argon, containing trace amounts of halogen elements (iodine, bromine, etc.). The introduction of halogen elements makes it possible to set the filament temperature at a high temperature while preventing filament breakage. Therefore, compared to standard incandescent light bulbs, halogen lamps HL have the characteristics of a longer lifespan and the ability to continuously emit strong light. In other words, halogen lamps HL are continuous lamps that emit light continuously for at least one second. Furthermore, because halogen lamps HL are rod-shaped, they have a long lifespan, and by arranging them horizontally, they achieve excellent radiation efficiency toward the semiconductor wafer W above.

[0053] Also, a reflector 43 is provided below the two-tiered halogen lamps HL inside 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.

[0054] As shown in FIG. 1 , the chamber 6 is provided with two radiation thermometers (pyrometers in this embodiment): an upper radiation thermometer 25 and a lower radiation thermometer 20. The upper radiation thermometer 25 is installed diagonally above the semiconductor wafer W held on the susceptor 74 and receives infrared light radiated from the top surface of the semiconductor wafer W to measure the temperature of the top surface. The infrared sensor 29 of the upper radiation thermometer 25 is equipped with an InSb (indium antimonide) optical element so as to be able to respond to a sudden temperature change on the top surface of the semiconductor wafer W at the moment when the flash light is irradiated. On the other hand, the lower radiation thermometer 20 is installed diagonally below the semiconductor wafer W held on the susceptor 74 and receives infrared light radiated from the bottom surface of the semiconductor wafer W to measure the temperature of the bottom surface.

[0055] A high-speed camera 95 is also provided in the chamber 6. The high-speed camera 95 is provided to the side of the susceptor 74 installed in the chamber 6, and photographs the semiconductor wafer W held on the susceptor 74 from the side. The photographing pitch of the high-speed camera 95 is set to any value between 10 microseconds (100,000 fps) and 1,000 microseconds (1,000 fps). Note that, for convenience of illustration in FIG. 1, the high-speed camera 95 is provided at the transfer opening 66, but in reality, the high-speed camera 95 is not provided at the transfer opening 66 but at a position where it does not interfere with the transfer of the semiconductor wafer W or with temperature measurement by a radiation thermometer.

[0056] The control unit 3 controls the various operating mechanisms provided in the heat treatment apparatus 1. FIG. 8 is a block diagram showing the configuration of the control unit 3. 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 storage unit 34 (e.g., a magnetic disk) that stores control software, data, and the like. The CPU of the control unit 3 executes a predetermined processing program, causing the heat treatment apparatus 1 to perform processing.

[0057] The control unit 3 includes an angle calculation unit 31, an emissivity calculation unit 32, and a temperature correction unit 33. Each of the angle calculation unit 31, the emissivity calculation unit 32, and the temperature correction unit 33 is a functional processing unit realized by the CPU of the control unit 3 executing a predetermined processing program. The processing details of the angle calculation unit 31, the emissivity calculation unit 32, and the temperature correction unit 33 will be described further below. Furthermore, the memory unit 34 of the control unit 3 stores a table 35 ( FIG. 11 ) indicating the correlation between the measurement angle of the upper radiation thermometer 25 and the apparent emissivity of the semiconductor wafer W.

[0058] The control unit 3 is electrically connected to elements such as a high-speed camera 95. The control unit 3 receives image data captured by the high-speed camera 95 and performs predetermined image processing on the image. The control unit 3 also controls the output of the halogen lamp HL, the operation of the transfer mechanism 10, etc.

[0059] A display unit 37 and an input unit 36 are also connected to the control unit 3. The display unit 37 and the input unit 36 function as a user interface for the heat treatment device 1. The control unit 3 displays various information on the display unit 37. An operator of the heat treatment device 1 can input various commands and parameters from the input unit 36 while checking the information displayed on the display unit 37. The input unit 36 can be, for example, a keyboard or a mouse. The display unit 37 can be, for example, a liquid crystal display. In this embodiment, a liquid crystal touch panel provided on the outer wall of the heat treatment device 1 is used as the display unit 37 and the input unit 36, thereby combining the functions of both.

[0060] In addition to the above configuration, the heat treatment apparatus 1 is equipped with various cooling structures to prevent excessive temperature rise in the halogen heating unit 4, flash heating unit 5, and chamber 6 due to the thermal energy generated by the halogen lamps HL and flash lamps FL during heat treatment of the semiconductor wafer W. For example, a water-cooled pipe (not shown) is provided in the wall of the chamber 6. The halogen heating unit 4 and flash heating unit 5 also have an air-cooled structure that creates 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 upper chamber window 63.

[0061] Next, a description will be given of the processing operation in the heat treatment apparatus 1 having the above configuration. Fig. 9 is a flowchart showing the procedure of the processing operation in the heat treatment apparatus 1. The processing procedure of the heat treatment apparatus 1 described below progresses as the control unit 3 controls each operating mechanism of the heat treatment apparatus 1.

[0062] First, the air supply valve 84 is opened, and the exhaust valves 89, 192 are 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 through the gas supply hole 81. When the valve 89 is opened, the gas inside the chamber 6 is exhausted through the gas exhaust hole 86. As a result, the nitrogen gas supplied from the upper part of the heat treatment space 65 inside the chamber 6 flows downward and is exhausted from the lower part of the heat treatment space 65.

[0063] Furthermore, by opening the valve 192, the gas inside the chamber 6 is also exhausted from the transfer opening 66. Furthermore, the atmosphere around the drive unit of the transfer mechanism 10 is also exhausted by an exhaust mechanism (not shown). Note that during the heat treatment of the semiconductor wafer W in the heat treatment apparatus 1, nitrogen gas is continuously supplied to the heat treatment space 65, and the supply amount is changed as appropriate depending on the treatment process.

[0064] Next, gate valve 185 is opened to open transfer opening 66, and a semiconductor wafer W to be processed is loaded into heat treatment space 65 in chamber 6 through transfer opening 66 by a transfer robot outside the apparatus (step S1). At this time, there is a risk that the atmosphere outside the apparatus may be drawn in as the semiconductor wafer W is loaded, but since nitrogen gas is continuously supplied to chamber 6, the nitrogen gas flows out from transfer opening 66, making it possible to minimize the inclusion of such external atmosphere.

[0065] The semiconductor wafer W carried in by the transfer 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 retracted 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 higher than the upper ends of the substrate support pins 77.

[0066] After the semiconductor wafer W is placed on the lift pins 12, the transfer robot exits the heat treatment space 65, and the transfer opening 66 is closed by the gate valve 185. Then, the pair of transfer arms 11 descend, transferring the semiconductor wafer W from the transfer mechanism 10 to the susceptor 74 of the holder 7, where it is held horizontally from below. The semiconductor wafer W is supported by a plurality of substrate support pins 77 erected on the holding plate 75 and held on the susceptor 74. The semiconductor wafer W is held on the holder 7 with its front surface, which is the surface to be processed, facing upward. 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, which have descended to below the susceptor 74, are retracted to a retracted position, i.e., inside the recess 62, by the horizontal movement mechanism 13.

[0067] After the semiconductor wafer W is held from below in a horizontal position by the susceptor 74 of the holder 7, which is made of quartz, the 40 halogen lamps HL of the halogen heating unit 4 are simultaneously turned on to begin preheating (assisted heating) (step S2). The halogen light emitted from the halogen lamps HL passes through the lower chamber window 64 and the susceptor 74, both of which are 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, so it does not interfere with heating by the halogen lamps HL.

[0068] The temperature of the semiconductor wafer W, which is heated by the light irradiation from the halogen lamps HL, is measured by the lower 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. In other words, the control unit 3 feedback-controls the output of the halogen lamps HL based on the measurement value by the lower radiation thermometer 20 so that the temperature of the semiconductor wafer W becomes the preheating temperature T1. The lower radiation thermometer 20 is a temperature sensor for controlling the output of the halogen lamps HL.

[0069] 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 lower 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.

[0070] By performing preheating using the halogen lamps HL in this manner, the temperature of the entire semiconductor wafer W is uniformly raised to the preheating temperature T1. During preheating using the halogen lamps HL, the temperature of the peripheral portion of the semiconductor wafer W, where heat dissipation is more likely, tends to be lower than that of the central portion, but the arrangement density of the halogen lamps HL in the halogen heating unit 4 is higher in the region facing the peripheral portion of the semiconductor wafer W than in the region facing the central portion. As a result, a greater amount of light is irradiated onto the peripheral portion of the semiconductor wafer W, where heat dissipation is more likely, and the in-plane temperature distribution of the semiconductor wafer W during the preheating stage can be made uniform.

[0071] 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 (step S3). At this time, part of the flash light emitted from the flash lamps FL heads directly into the chamber 6, and the other part is reflected by the reflector 52 before heading into the chamber 6, and the semiconductor wafer W is flash-heated by the irradiation of these flash lights.

[0072] Flash heating is performed by irradiating a flash of light (flash of light) from flash lamps FL, which allows the surface temperature of the semiconductor wafer W to rise in a short time. That is, the flash of light irradiated from the flash lamps FL is an extremely short, intense flash of light with an irradiation time of approximately 0.1 milliseconds 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 of light from the flash lamps FL instantaneously rises to a processing temperature T2 of 1000°C or higher and then rapidly drops.

[0073] When a flash of light with an extremely short irradiation time is applied, the temperature near the front surface of the semiconductor wafer W rises rapidly, while the temperature of the back surface does not rise significantly from the preheating temperature T1. As a result, rapid thermal expansion occurs only near the front surface of the semiconductor wafer W, causing the semiconductor wafer W to rapidly deform and warp with its upper surface convex. The high-speed camera 95 captures this behavior of the semiconductor wafer W when irradiated with the flash of light (step S4).

[0074] The high-speed camera 95 captures images of the behavior of the semiconductor wafer W from the side of the susceptor 74, i.e., from the horizontal direction. Therefore, when the semiconductor wafer W deforms so as to warp with its upper surface convex, the high-speed camera 95 can capture images of the warped state of the semiconductor wafer W. The high-speed camera 95 also captures images of the behavior of the semiconductor wafer W from at least the time when the flash lamps FL start irradiating the semiconductor wafer W with flash light. The high-speed camera 95 may also capture images of the semiconductor wafer W from an earlier time, for example, when the semiconductor wafer W is being preheated. The high-speed camera 95 also captures images of the semiconductor wafer W at a capture interval of 10 microseconds to 1000 microseconds (40 microseconds in this embodiment). Data of the multiple images captured by the high-speed camera 95 is stored, for example, in the memory unit 34.

[0075] Meanwhile, the upper radiation thermometer 25 measures the surface temperature of the semiconductor wafer W being flash-heated (step S5). The upper radiation thermometer 25 measures the surface temperature of the semiconductor wafer W from diagonally above the semiconductor wafer W. The upper radiation thermometer 25 measures the surface temperature of the semiconductor wafer W at least from the point when the flash lamps FL start irradiating the semiconductor wafer W with flash light. As with the high-speed camera 95 described above, the upper radiation thermometer 25 may be configured to measure the surface temperature of the semiconductor wafer W earlier, for example, from the time when the semiconductor wafer W is being preheated. In other words, steps S4 and S5 may be performed before step S3.

[0076] Furthermore, the sampling pitch at which the upper radiation thermometer 25 measures the temperature is preferably the same as the photographing pitch of the high-speed camera 95. Therefore, in this embodiment, the sampling pitch of the upper radiation thermometer 25 is 40 microseconds. With a sampling pitch of this order, the upper radiation thermometer 25 can appropriately measure the surface temperature of the semiconductor wafer W, which changes rapidly due to flash light irradiation. The temperature data measured by the upper radiation thermometer 25 is stored in, for example, the memory unit 34.

[0077] 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 decrease from the preheating temperature T1. The temperature of the semiconductor wafer W during this decrease is measured by the lower radiation thermometer 20, and the measurement result is transmitted to the control unit 3. The control unit 3 monitors, based on the measurement result of the lower radiation thermometer 20, whether the temperature of the semiconductor wafer W has decreased to a predetermined temperature. After the temperature of the semiconductor wafer W has decreased to or below the predetermined temperature, the pair of transfer arms 11 of the transfer mechanism 10 again move horizontally from the retracted position to the transfer operation position and rise, causing the lift pins 12 to protrude from the upper surface of the susceptor 74 and receive the heat-treated semiconductor wafer W from the susceptor 74. Next, the transfer opening 66, which had been closed by the gate valve 185, is opened, and the semiconductor wafer W placed on the lift pins 12 is removed from the chamber 6 by a transfer robot external to the apparatus, completing the heat treatment of the semiconductor wafer W (step S6).

[0078] The surface temperature of the semiconductor wafer W, which rises and falls rapidly during flash light irradiation, is measured by the upper pyrometer 25. However, during flash light irradiation, the temperature rises rapidly only near the surface of the semiconductor wafer W, causing thermal expansion and resulting in deformation of the semiconductor wafer W. As a result, the apparent emissivity of the semiconductor wafer W as seen from the upper pyrometer 25 fluctuates, making it difficult to accurately measure the surface temperature of the semiconductor wafer W. Therefore, in this embodiment, steps S7 to S9 are performed to accurately measure the surface temperature of the semiconductor wafer W during flash light irradiation. The processes of steps S7 to S9 are performed after the flash heating process of the semiconductor wafer W is completed and before the subsequent semiconductor wafer W is loaded into the chamber 6.

[0079] First, the angle calculation unit 31 (FIG. 8) calculates the measurement angle between the upper pyrometer 25 and the semiconductor wafer W when the semiconductor wafer W is deformed by the irradiation of the flash light (step S7). The memory unit 34 stores data on multiple images of the semiconductor wafer W captured by the high-speed camera 95 when the flash light was irradiated. The angle calculation unit 31 performs binarization processing on each image stored in the memory unit 34 to obtain a binary image. The binarization processing is an image processing that converts the target image into two gradations of black and white. By performing binarization processing on the image captured from the side of the semiconductor wafer W by the high-speed camera 95, the semiconductor wafer W is recognized as a line.

[0080] The angle calculation unit 31 performs further image processing on the obtained binary image to calculate the measurement angle between the upper radiation thermometer 25 and the semiconductor wafer W. FIG. 10 is a diagram showing the measurement angle between the upper radiation thermometer 25 and the semiconductor wafer W. The two-dot chain line in FIG. 10 indicates the semiconductor wafer W held in a horizontal position on the susceptor 74 before the flash light is irradiated. On the other hand, the solid line in FIG. 10 indicates the semiconductor wafer W deformed by the flash light irradiation. The measurement angle between the upper radiation thermometer 25 and the semiconductor wafer W is the angle formed between the optical axis of the infrared sensor 29 of the upper radiation thermometer 25 and the normal to the semiconductor wafer W. The measurement angle θ2 between the upper radiation thermometer 25 and the semiconductor wafer W deformed by the flash light irradiation is smaller than the measurement angle θ1 between the upper radiation thermometer 25 and the semiconductor wafer W that is not deformed before the flash light irradiation.

[0081] The angle calculation unit 31 calculates the measurement angle between the upper radiation thermometer 25 and the semiconductor wafer W deformed by flash light irradiation through image processing. Depending on the sampling pitch of the temperature measurement by the upper radiation thermometer 25, the angle calculation unit 31 may calculate the measurement angle for all of the multiple images captured by the high-speed camera 95, or may calculate the measurement angle by extracting some of the images. For example, as in the present embodiment, when the sampling pitch of the upper radiation thermometer 25 is the same as the shooting pitch of the high-speed camera 95, the angle calculation unit 31 preferably calculates the measurement angle for all of the captured images. On the other hand, when the sampling pitch of the upper radiation thermometer 25 is longer than the shooting pitch of the high-speed camera 95, the angle calculation unit 31 preferably calculates the measurement angle by extracting some of the captured images. For example, when the sampling pitch of the upper radiation thermometer 25 is 40 microseconds and the shooting pitch of the high-speed camera 95 is 10 milliseconds, the angle calculation unit 31 may calculate the measurement angle by extracting one of every four captured images.

[0082] Next, emissivity calculation unit 32 calculates the apparent emissivity of semiconductor wafer W as viewed from upper radiation thermometer 25 based on the measurement angle calculated by angle calculation unit 31 (step S8). The apparent emissivity of the surface of semiconductor wafer W is a parameter that varies depending on the measurement angle between upper radiation thermometer 25 and semiconductor wafer W. The correlation between the apparent emissivity of the surface of semiconductor wafer W and the measurement angle between upper radiation thermometer 25 and semiconductor wafer W is calculated in advance by experiment, simulation, or the like, and stored in storage unit 34 as table 35. FIG. 11 is a diagram showing an example of table 35 that specifies the correlation between measurement angle and emissivity.

[0083] The emissivity calculation unit 32 identifies the emissivity of the semiconductor wafer W corresponding to the measurement angle calculated in step S7 from the table 35. The emissivity thus identified by the emissivity calculation unit 32 is the apparent emissivity of the surface of the semiconductor wafer W as seen from the upper radiation thermometer 25 at the above measurement angle.

[0084] Next, the temperature correction unit 33 corrects the temperature of the semiconductor wafer W measured by the upper radiation thermometer 25 based on the apparent emissivity of the semiconductor wafer W calculated by the emissivity calculation unit 32 (step S9). When the upper radiation thermometer 25 measures the surface temperature of the semiconductor wafer W being flash-heated in step S5, an appropriate value of the emissivity of the semiconductor wafer W (e.g., the emissivity when the semiconductor wafer W is not deformed) is set in the upper radiation thermometer 25. However, there is a difference between the set emissivity and the apparent emissivity of the semiconductor wafer W that is deformed by flash light irradiation, and this difference causes an error in the temperature measurement. For this reason, in this embodiment, the temperature measured by the upper radiation thermometer 25 is corrected based on the accurate apparent emissivity of the deformed semiconductor wafer W. Specifically, the emissivity set in the upper radiation thermometer 25 is replaced with the apparent emissivity of the semiconductor wafer W calculated in step S8, and the temperature measured by the upper radiation thermometer 25 is corrected by performing a calculation process to calculate the temperature of the semiconductor wafer W.

[0085] In this embodiment, the behavior of the semiconductor wafer W, which rapidly deforms when irradiated with flash light, is captured at predetermined intervals (40 microseconds in this embodiment) using a high-speed camera 95 to obtain multiple images. From the multiple images, the angle calculation unit 31 calculates the measurement angle between the upper pyrometer 25 and the semiconductor wafer W at each predetermined interval. Then, the emissivity calculation unit 32 calculates the apparent emissivity of the semiconductor wafer W as viewed from the upper pyrometer 25 at each predetermined interval from the table 35 based on the measurement angle. Furthermore, the temperature correction unit 33 corrects the temperature of the semiconductor wafer W measured by the upper pyrometer 25 at each predetermined interval based on the calculated emissivity. In this way, even when the semiconductor wafer W rapidly deforms when irradiated with flash light, the measured temperature of the semiconductor wafer W is corrected based on the emissivity corresponding to the measurement angle depending on the warpage of the semiconductor wafer W, thereby enabling accurate measurement of the temperature of the semiconductor wafer W when irradiated with flash light.

[0086] Although the above describes an embodiment of the present invention, various modifications can be made to the present invention without departing from the spirit and scope of the present invention. For example, in step S4 of FIG. 9, multiple high-speed cameras may be used to capture images of the behavior of the semiconductor wafer W during flash irradiation. FIG. 12 illustrates an example in which two high-speed cameras are used to capture images of the semiconductor wafer W. In the example of FIG. 12, a first high-speed camera 95a and a second high-speed camera 95b capture images of the behavior of the semiconductor wafer W from the side of the susceptor 74, spaced 90° from each other. This allows for more accurate capture of the warpage of the semiconductor wafer W during flash irradiation, thereby enabling more accurate calculation of the measurement angle between the upper pyrometer 25 and the semiconductor wafer W. Note that the number of high-speed cameras may be three or more. While increasing the number of high-speed cameras allows for more accurate capture of the warpage of the semiconductor wafer W, the subsequent image processing becomes more complex and the installation costs of the high-speed cameras also increase.

[0087] Furthermore, in the above embodiment, the warpage state of the semiconductor wafer W was actually measured by capturing an image using a high-speed camera 95. However, this may also be determined by simulation. FIG. 13 illustrates an example of a process for determining the warpage state using simulation. When using simulation, a model is created in advance that derives results such as the temperature distribution of the semiconductor wafer W when various processing conditions in the heat treatment apparatus 1 are input. Machine learning may also be used to create the model. Then, by setting processing conditions for the semiconductor wafer W to be processed (e.g., the lamp power of the halogen lamps HL used for preheating, the charging voltage of the capacitor supplying power to the flash lamps FL, etc.) as input parameters to the model, the in-plane temperature distribution of the semiconductor wafer W during flash light irradiation can be obtained as an output. Once the in-plane temperature distribution of the semiconductor wafer W is obtained, the warpage state of the semiconductor wafer W during flash light irradiation can be determined from the obtained in-plane temperature distribution. The model that outputs the in-plane temperature distribution of the semiconductor wafer W and the model that outputs the warpage state may be separate, or they may be incorporated into a single model.

[0088] If the warpage state of the semiconductor wafer W when irradiated with flash light can be obtained by a simulation using a model, the measurement angle between the upper radiation thermometer 25 and the semiconductor wafer W can be calculated from the obtained value. Next, as in the above embodiment, the apparent emissivity of the semiconductor wafer W as seen from the upper radiation thermometer 25 is calculated based on the calculated measurement angle. Then, the temperature of the semiconductor wafer W measured by the upper radiation thermometer 25 is corrected based on the calculated apparent emissivity of the semiconductor wafer W. Even in this case, as in the above embodiment, the measured temperature of the semiconductor wafer W is corrected based on the emissivity corresponding to the measurement angle depending on the warpage state of the semiconductor wafer W, and therefore the temperature of the semiconductor wafer W when irradiated with flash light can be accurately measured.

[0089] The simulation using the above-described model may be performed by the control unit 3 of the heat treatment apparatus 1, or may be executed by a computer system separate from the heat treatment apparatus 1. Furthermore, the angle calculation unit 31, the emissivity calculation unit 32, and the temperature correction unit 33 of the above-described embodiment are not limited to being provided in the control unit 3, and may be realized in a computer system separate from the heat treatment apparatus 1. The computer system and the heat treatment apparatus 1 constitute a heat treatment system.

[0090] Furthermore, in the above embodiment, the surface temperature of the semiconductor wafer W measured by the upper radiation thermometer 25 is corrected, but instead, the back surface temperature of the semiconductor wafer W measured by the lower radiation thermometer 20 may be corrected. In this case, as in the above embodiment, the measurement angle between the lower radiation thermometer 20 and the semiconductor wafer W is calculated from the warpage state of the semiconductor wafer W when irradiated with flash light, the emissivity corresponding to that measurement angle is found, and the back surface temperature of the semiconductor wafer W measured by the lower radiation thermometer 20 is corrected based on the found emissivity.

[0091] Furthermore, in the above embodiment, the processing of steps S7 to S9 is performed after the flash heating process of the semiconductor wafer W is completed, but if sufficiently high-speed calculation processing can be performed, it is also possible to determine the emissivity corresponding to the measurement angle depending on the warpage state of the semiconductor wafer W, and immediately set that emissivity in the upper radiation thermometer 25 to measure the temperature of the semiconductor wafer W. In this way, it is possible to perform real-time temperature measurement taking into account the warpage state of the semiconductor wafer W, and to accurately measure the temperature of the semiconductor wafer W when irradiated with flash light.

[0092] Furthermore, 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. Furthermore, the flash lamps FL are not limited to xenon flash lamps and may be krypton flash lamps. Furthermore, the number of halogen lamps HL provided in the halogen heating unit 4 is not limited to 40 and can be any number.

[0093] Furthermore, in the above embodiment, the preheating process of the semiconductor wafer W is performed using a filament-type halogen lamp HL as a continuously lit lamp that emits light continuously for one second or more, but this is not limited to this, and the preheating process may also be performed using a discharge-type arc lamp (e.g., a xenon arc lamp) or an LED lamp as a continuously lit lamp instead of the halogen lamp HL. [Explanation of symbols]

[0094] 1. Heat treatment equipment 3. Control Unit 4 Halogen heating section 5 Flash heating section 6 chambers 7 Holding part 10 Transfer mechanism 20 Lower radiation thermometer 25 Upper radiation thermometer 31 Angle calculation section 32 Emissivity calculation section 33 Temperature correction section 34 Storage section 35 tables 63 Upper chamber window 64 Lower chamber window 65 Heat Treatment Space 74 Susceptor 95 High-Speed Camera FL flash lamp HL halogen lamp W Semiconductor wafer

Claims

1. A temperature measurement method for measuring a temperature of a substrate that changes due to flash light irradiation, comprising: an irradiation step of irradiating a surface of the substrate with flash light from a flash lamp; an angle calculation step of calculating a measurement angle between the radiation thermometer and the substrate when the substrate is deformed by irradiation with flash light; an emissivity calculation step of calculating the emissivity of the substrate as seen from the radiation thermometer based on the measurement angle calculated in the angle calculation step; a correction step of correcting the temperature of the substrate measured by the radiation thermometer based on the emissivity calculated in the emissivity calculation step; A temperature measurement method comprising:

2. 2. The temperature measurement method according to claim 1, A temperature measuring method characterized in that in the angle calculation step, the measurement angle is calculated from a binary image obtained by binarizing an image of the substrate taken by a camera when irradiated with flash light.

3. 3. The temperature measurement method according to claim 2, In the angle calculation step, the camera captures images of the substrate at predetermined intervals, In the emissivity calculation step, the emissivity is calculated at each predetermined interval, The temperature measuring method, wherein the correction step corrects the temperature of the substrate at each predetermined interval.

4. 2. The temperature measurement method according to claim 1, The temperature measuring method according to claim 1, wherein the emissivity calculation step calculates the emissivity from a table showing the correlation between the measurement angle and the emissivity.

5. 2. The temperature measurement method according to claim 1, A temperature measuring method characterized in that in the angle calculation step, the measurement angle is calculated based on the warpage state of the substrate obtained from a simulation in which processing conditions are set as input parameters for a model.

6. A thermal processing system that heats a substrate by irradiating the substrate with flash light, comprising: a chamber for housing the substrate; a holder that holds the substrate in the chamber; a flash lamp that irradiates the substrate held by the holder with a flash of light; a radiation thermometer for measuring the temperature of the substrate; an angle calculation unit that calculates a measurement angle between the radiation thermometer and the substrate when the substrate is deformed by irradiation with flash light; an emissivity calculation unit that calculates the emissivity of the substrate as seen from the radiation thermometer based on the measurement angle calculated by the angle calculation unit; a temperature correction unit that corrects the temperature of the substrate measured by the radiation thermometer based on the emissivity calculated by the emissivity calculation unit; A heat treatment system comprising:

7. 7. The heat treatment system of claim 6, further comprising a camera that captures an image of the substrate held by the holder; The heat treatment system is characterized in that the angle calculation unit calculates the measurement angle from a binary image obtained by binarizing an image of the substrate captured by the camera when irradiated with flash light.

8. 8. The heat treatment system of claim 7, the camera captures images of the substrate at predetermined intervals while irradiated with flash light; the emissivity calculation unit calculates the emissivity at each predetermined interval, The thermal processing system is characterized in that the temperature correction unit corrects the temperature of the substrate at the predetermined intervals.

9. 7. The heat treatment system of claim 6, further comprising a storage unit that stores a table showing the correlation between the measurement angle and the emissivity; The heat treatment system is characterized in that the emissivity calculation unit calculates the emissivity from the table.

10. 7. The heat treatment system of claim 6, The heat treatment system is characterized in that the angle calculation unit calculates the measurement angle based on a warpage state of the substrate obtained from a simulation in which processing conditions are set as input parameters for a model.

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