Temperature measurement method

Abstract

The present invention provides a temperature measurement method that can accurately measure the surface temperature of a substrate even if the emissivity of both the front and back surfaces of the substrate is unknown. A wafer with a thermocouple mounted on its surface is heated using light from a halogen lamp, and the surface temperature of the wafer with the thermocouple is measured using the thermocouple, while the temperature of the back surface is measured using a back-side radiation thermometer. The emissivity set in the back-side radiation thermometer is corrected based on the temperature of the wafer with the thermocouple measured by the thermocouple. Next, a semiconductor wafer with a pattern formed on its surface is heated using light from a halogen lamp, and the temperatures of the back and surface of the semiconductor wafer are measured using a back-side radiation thermometer and a front-side radiation thermometer, respectively. The emissivity set in the front-side radiation thermometer is corrected based on the temperature of the semiconductor wafer measured by the back-side radiation thermometer.

Description

Technical Field

[0001] The present invention relates to a temperature measurement method for measuring the temperature of a thin plate-shaped precision electronic substrate (hereinafter simply referred to as a "substrate") such as a semiconductor wafer in a non-contact manner. Background Art

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

[0003] The radiation spectrum of a xenon flash lamp extends from the ultraviolet to the near-infrared region, with wavelengths shorter than those of conventional halogen lamps and nearly coinciding with the intrinsic absorption band of silicon semiconductor wafers. Therefore, when a xenon flash lamp irradiates a semiconductor wafer with a flash, the transmitted light can rapidly heat the wafer. Furthermore, it has been shown that extremely short flash irradiation times, under a few milliseconds, can selectively heat only the area near the surface of the semiconductor wafer.

[0004] Flash lamp annealing is used for processes requiring extremely short heating times, typically for activating impurities implanted into semiconductor wafers. By irradiating the surface of a semiconductor wafer into which impurities have been implanted by ion implantation with a flash lamp, the surface temperature of the semiconductor wafer can be raised to the activation temperature in an extremely short period of time, allowing only impurity activation to be performed without causing the impurities to diffuse deeply.

[0005] Managing wafer temperature is crucial not only in flash lamp annealing but also in the thermal processing of semiconductor wafers. Typically, a radiation thermometer is used to measure the temperature of a semiconductor wafer during thermal processing in a non-contact manner. To achieve high-precision temperature measurement using a radiation thermometer, the emissivity of the object being measured must be accurately set in the radiation thermometer. Therefore, in order to accurately measure the surface temperature of a semiconductor wafer, which rapidly changes during flash irradiation, the radiation thermometer must be set to the emissivity of the semiconductor wafer surface.

[0006] However, a semiconductor wafer exposed to a flash of light typically forms a pattern on its surface. The surface emissivity of a semiconductor wafer depends on the pattern. That is, different patterns on the surface of a semiconductor wafer result in different surface emissivities. Therefore, it is necessary to determine the surface emissivity of each semiconductor wafer to be heat-treated and set this surface emissivity in the radiation thermometer.

[0007] Patent Document 1 discloses a technique for accurately measuring the back surface temperature of a semiconductor wafer whose back surface emissivity is known, calculating the emissivity of the semiconductor wafer's surface based on the measured emissivity, and thereby measuring the surface temperature. Patent Document 2 discloses a technique for measuring the temperature of a semiconductor wafer by placing a monitoring wafer with a known emissivity close to a semiconductor wafer to be measured, and calculating the emissivity of the semiconductor wafer based on the temperature measurement of the monitoring wafer.

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2014-185898

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 5-299428.

[0010] However, the technique disclosed in Patent Document 1 cannot be applied unless the emissivity of the back surface of the semiconductor wafer is known. Meanwhile, the technique disclosed in Patent Document 2 requires the preparation of a separate monitor wafer whose emissivity is known. Furthermore, the technique disclosed in Patent Document 2 places the monitor wafer in contact with the semiconductor wafer being measured, potentially damaging the pattern formed on the surface of the semiconductor wafer. Summary of the Invention

[0011] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a heat treatment method capable of accurately measuring the surface temperature of a substrate even if the emissivities of the front and back surfaces of the substrate are unknown.

[0012] In order to solve the above-mentioned problems, the invention of Technical Solution 1 is a temperature measurement method for measuring the temperature of a substrate, wherein the temperature measurement method includes the following steps: a first correction step, heating a first substrate having a contact thermometer mounted on the surface, and measuring the temperature of the back side of the first substrate using a back-side radiation thermometer, and correcting the emissivity set in the back-side radiation thermometer based on the temperature of the first substrate measured by the contact thermometer; a second correction step, heating a second substrate having a pattern formed on the surface, and measuring the temperatures of the back and surface of the second substrate using the back-side radiation thermometer and the surface-side radiation thermometer respectively, and correcting the emissivity set in the surface-side radiation thermometer based on the temperature of the second substrate measured by the back-side radiation thermometer; and a temperature measurement step, measuring the surface temperature of the second substrate heated by irradiated light using the surface-side radiation thermometer.

[0013] The invention according to claim 2 is the temperature measurement method according to claim 1 , wherein in the first calibration step and the second calibration step, the first substrate and the second substrate are heated by light irradiation from a continuously lit lamp.

[0014] In addition, the invention of Technical Solution 3 is the temperature measurement method of the invention of Technical Solution 2, wherein, in the first correction process, when the first substrate is maintained at a specified temperature by irradiating light from the continuously lighting lamp, the temperature of the first substrate is measured using the contact thermometer and the back side radiation thermometer, and in the second correction process, when the second substrate is maintained at a specified temperature by irradiating light from the continuously lighting lamp, the temperature of the second substrate is measured using the back side radiation thermometer and the surface side radiation thermometer.

[0015] In addition, the invention of Technical Solution 4 is the temperature measurement method of the invention of Technical Solution 1, wherein, in the temperature measurement process, the surface side radiation thermometer is used to measure the temperature of the surface of the second substrate that is heated when the flash is irradiated from the flash lamp to the surface of the second substrate.

[0016] In addition, the invention of Technical Solution 5 is the temperature measurement method of the invention of Technical Solution 1, wherein the installation position of the contact thermometer and the temperature measurement position of the back side radiation thermometer are symmetrical positions with respect to the first substrate, and the temperature measurement position of the back side radiation thermometer and the temperature measurement position of the surface side radiation thermometer are symmetrical positions with respect to the second substrate.

[0017] The invention according to claim 6 is the temperature measurement method according to claim 1 , wherein the light receiving element of the surface-side radiation thermometer is cooled to 0° C. or lower when measuring the surface temperature of the second substrate.

[0018] Furthermore, the invention according to claim 7 is the temperature measurement method according to the invention according to claim 1 , wherein the wall surface of the chamber accommodating the first substrate and the second substrate is cooled.

[0019] In addition, the invention according to claim 8 is the temperature measurement method according to any one of claims 1 to 7 , wherein the contact thermometer is a thermocouple.

[0020] According to the invention of technical solutions 1 to technical solutions 8, since the emissivity set at the back-side radiation thermometer is corrected based on the temperature of the first substrate measured by the contact thermometer, and the emissivity set at the surface-side radiation thermometer is corrected based on the temperature of the second substrate measured by the back-side radiation thermometer, the emissivity set at the back-side radiation thermometer and the surface-side radiation thermometer is corrected in two stages based on the accurate temperature measurement value obtained by the contact thermometer, the surface temperature of the substrate can be accurately measured even if the emissivity of the surface and back of the substrate is unknown.

[0021] In particular, according to the invention of technical solution 3, since temperature measurement is performed while the first substrate and the second substrate are maintained at a specified temperature, there is no temperature difference between the surface and back surface of the first substrate and the surface and back surface of the second substrate, thereby accurately correcting the emissivity set on the back side radiation thermometer and the surface side radiation thermometer.

[0022] In particular, according to the invention of technical solution 5, since the installation position of the contact thermometer and the temperature measurement position of the back-side radiation thermometer are symmetrical positions with the first substrate clamped therebetween, and the temperature measurement position of the back-side radiation thermometer and the temperature measurement position of the surface-side radiation thermometer are symmetrical positions with the second substrate clamped therebetween, there is no temperature difference between the surface and back of the first substrate and the surface and back of the second substrate, thereby enabling accurate correction of the emissivity set on the back-side radiation thermometer and the surface-side radiation thermometer.

[0023] In particular, according to the invention of technical solution 6, since the light receiving element of the surface side radiation thermometer is cooled to below 0°C when measuring the surface temperature of the second substrate, the light receiving element of the surface side radiation thermometer can maintain high sensitivity, thereby accurately measuring the surface temperature of the substrate.

[0024] In particular, according to the invention of claim 7, since the wall surface of the chamber is cooled, the influence of stray light incident on the rear-side radiation thermometer and the front-side radiation thermometer can be suppressed, thereby preventing a decrease in temperature measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a longitudinal sectional view showing the structure of a heat treatment apparatus for implementing the temperature measurement method of the present invention.

[0026] Figure 2 It is a perspective view showing the overall appearance of the holding portion.

[0027] Figure 3 This is a top view of the base.

[0028] Figure 4 This is a cross-sectional view of the base.

[0029] Figure 5 It is a top view of the transfer mechanism.

[0030] Figure 6 It is a side view of the transfer mechanism.

[0031] Figure 7 It is a plan view showing the arrangement of a plurality of halogen lamps.

[0032] Figure 8 This is a functional block diagram of the front-side radiation thermometer and the back-side radiation thermometer.

[0033] Figure 9 This is a flowchart showing the procedure of the temperature measurement method of the present invention.

[0034] Figure 10 This is a diagram schematically illustrating emissivity correction of the rear-side radiation thermometer based on the measurement value of the thermocouple.

[0035] Figure 11 This is a diagram schematically illustrating the emissivity correction of the front-side radiation thermometer based on the measurement value of the back-side radiation thermometer.

[0036] Description of reference numerals:

[0037] 1: Heat treatment device

[0038] 3: Control Department

[0039] 4: Halogen heating unit

[0040] 5: Flash heating unit

[0041] 6: Chamber

[0042] 7: Maintaining part

[0043] 10: Transfer mechanism

[0044] 20: Back side radiation thermometer

[0045] 25: Surface radiation thermometer

[0046] 63: Upper chamber window

[0047] 64: Lower chamber window

[0048] 65: Heat treatment space

[0049] 74: Base

[0050] 95: Cooling element

[0051] 99: Thermocouple

[0052] FL: Flash

[0053] HL: Halogen lamp

[0054] TW: Wafer with thermocouple

[0055] W: semiconductor wafer DETAILED DESCRIPTION

[0056] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0057] Figure 1 It is a longitudinal sectional view showing the structure of a heat treatment apparatus 1 for implementing the temperature measurement method of the present invention. Figure 1The heat treatment device 1 is a flash lamp annealing device that heats a disk-shaped semiconductor wafer W as a substrate by irradiating a flash of light onto the semiconductor wafer W. The size of the semiconductor wafer W to be processed is not particularly limited, and is, for example, φ300 mm or φ450 mm (φ300 mm in this embodiment). Figure 1 In the following figures, the size and number of each part are exaggerated or simplified as needed to facilitate understanding.

[0058] Heat treatment apparatus 1 includes a chamber 6 for accommodating semiconductor wafers W, a flash heating unit 5 containing multiple flash lamps FL, and a halogen heating unit 4 containing multiple halogen lamps HL. The flash heating unit 5 is located above chamber 6, while the halogen heating unit 4 is located below. Heat treatment apparatus 1 also includes a holding unit 7 within chamber 6 for holding semiconductor wafers W in a horizontal position, and a transfer mechanism 10 for transferring semiconductor wafers W between holding unit 7 and the outside of the apparatus. Heat treatment apparatus 1 also includes a control unit 3 that controls the halogen heating unit 4, flash heating unit 5, and various operating mechanisms within chamber 6 to perform heat treatment of semiconductor wafers W.

[0059] 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 generally cylindrical shape with openings at the top and bottom. An upper chamber window 63 is attached to the upper opening to block the upper opening, and a lower chamber window 64 is attached to the lower opening to block the lower opening. The upper chamber window 63, which forms the top of the chamber 6, is a circular plate-shaped member made of quartz and functions as a quartz window that allows the flash light emitted from the flash heating unit 5 to pass into the chamber 6. Furthermore, the lower chamber window 64, which forms the bottom of the chamber 6, is also a circular plate-shaped member made of quartz and functions as a quartz window that allows the light from the halogen heating unit 4 to pass into the chamber 6.

[0060] In addition, a reflection ring 68 is installed on the upper part of the inner wall of the chamber side portion 61, and a reflection ring 69 is installed on the lower part. The reflection rings 68 and 69 are both formed in a circular ring shape. The upper reflection ring 68 is installed by being embedded from the upper side of the chamber side portion 61. On the other hand, the lower reflection ring 69 is installed by being embedded from the lower side of the chamber side portion 61 and fixed with screws (not shown). In other words, the reflection rings 68 and 69 can be freely installed on the chamber side portion 61. The inner space of the chamber 6, that is, the space surrounded by the upper chamber window 63, the lower chamber window 64, the chamber side portion 61, and the reflection rings 68 and 69 is defined as the heat treatment space 65.

[0061] By attaching reflection rings 68 and 69 to chamber side portion 61, a recess 62 is formed on the inner wall of chamber 6. Specifically, recess 62 is formed by the central portion of the inner wall of chamber side portion 61 where reflection rings 68 and 69 are not attached, the lower end surface of reflection ring 68, and the upper end surface of reflection ring 69. Recess 62 is formed in a horizontal annular shape on the inner wall of chamber 6, surrounding holding portion 7 that holds semiconductor wafer W. Chamber side portion 61 and reflection rings 68 and 69 are formed from a metal material (e.g., stainless steel) with excellent strength and heat resistance.

[0062] Furthermore, a transport opening (furnace port) 66 for loading and unloading semiconductor wafers W into and out of the chamber 6 is formed in the chamber side portion 61. The transport opening 66 can be opened and closed by a gate valve 185. The transport opening 66 is connected to the outer peripheral surface of the recess 62. Therefore, when the gate valve 185 opens the transport opening 66, the semiconductor wafers W can be loaded into and unloaded from the heat treatment space 65 through the recess 62 from the transport opening 66. Furthermore, when the gate valve 185 closes the transport opening 66, the heat treatment space 65 within the chamber 6 becomes a sealed space.

[0063] Furthermore, through-holes 61a and 61b are formed through the chamber side portion 61. Through-hole 61a is a cylindrical hole that guides infrared light radiated from the upper surface of the semiconductor wafer W held by the susceptor 74 (described later) toward the infrared sensor 29 of the front-side radiation thermometer 25. Meanwhile, through-hole 61b is a cylindrical hole that guides infrared light radiated from the lower surface of the semiconductor wafer W toward the infrared sensor 24 of the back-side radiation thermometer 20. Through-holes 61a and 61b are arranged at an angle relative to the horizontal so that their axes of penetration intersect with the main surface of the semiconductor wafer W held by the susceptor 74. A transparent window 26 made of calcium fluoride is attached to the end of through-hole 61a facing the heat treatment space 65. This transparent window 26 transmits infrared light within the wavelength range measurable by the front-side radiation thermometer 25. A transparent window 21 made of barium fluoride is attached to the end of the through hole 61 b facing the heat treatment space 65 . The transparent window 21 transmits infrared light in a wavelength range measurable by the rear radiation thermometer 20 .

[0064] In addition, a gas supply hole 81 for supplying a processing gas to the heat treatment space 65 is provided on the upper portion of the inner wall of the chamber 6. The gas supply hole 81 is provided at a position higher than the recess 62, and may also be provided on the reflection ring 68. The gas supply hole 81 is 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. In addition, a valve 84 is installed in the middle of the path 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 flowing into the buffer space 82 flows in a manner that diffuses in the buffer space 82 having 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 thereof (nitrogen in this embodiment) can be used.

[0065] On the other hand, a gas exhaust hole 86 for exhausting the gas in the heat treatment space 65 is formed at the lower portion of the inner wall of the chamber 6. The gas exhaust hole 86 is formed at a position lower than the recess 62, and can also be provided on the reflection ring 69. The gas exhaust hole 86 is connected to the 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 the exhaust unit 190. In addition, a valve 89 is installed in the middle of the path of the gas exhaust pipe 88. When the valve 89 is opened, the gas in the heat treatment space 65 is discharged from the gas exhaust hole 86 through the buffer space 87 to the gas exhaust pipe 88. In addition, the gas supply hole 81 and the gas exhaust hole 86 can be provided in a plurality along the circumference of the chamber 6, or can be slit-shaped holes. In addition, the processing gas supply source 85 and the exhaust unit 190 can be a mechanism provided in the heat treatment apparatus 1, or can be a common device of a factory where the heat treatment apparatus 1 is provided.

[0066] A gas exhaust pipe 191 for exhausting the gas in the heat treatment space 65 is connected to the top end of the transfer opening 66. The gas exhaust pipe 191 is connected to the 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.

[0067] Figure 2 This is a perspective view showing the overall appearance of the holding portion 7. The holding portion 7 includes a base ring 71, a connecting portion 72, and a base 74. The base ring 71, the connecting portion 72, and the base 74 are all made of quartz. In other words, the entire holding portion 7 is made of quartz.

[0068] The base ring 71 is a quartz member with a circular arc shape formed by missing a portion of the circular ring. This missing portion is provided to prevent interference between the transfer arm 11 of the transfer mechanism 10 described later and the base ring 71. 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 Figure 1 ). A plurality of connection portions 72 (four in this embodiment) are provided on the upper surface of the base ring 71 along the circumference of the annular shape. The connection portions 72 are also made of quartz and are fixed to the base ring 71 by welding.

[0069] The base 74 is supported by four connecting portions 72 provided on the base ring 71 . Figure 3 74 is a top view of the base. Figure 4 This is a cross-sectional view of a 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 plate-shaped 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 dimension than the semiconductor wafer W.

[0070] A guide ring 76 is provided on the peripheral edge of the upper surface of the retaining plate 75. The guide ring 76 is a circular ring-shaped member having an inner diameter greater 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 peripheral surface of the guide ring 76 is formed into a tapered surface that extends upward from the retaining plate 75. The guide ring 76 is formed of quartz, similar to the retaining plate 75. The guide ring 76 can be welded to the upper surface of the retaining plate 75 or fixed to the retaining plate 75 using a separately processed pin or the like. Alternatively, the retaining plate 75 and the guide ring 76 can be processed as an integral member.

[0071] The area on the upper surface of the holding plate 75 that is further inward than the guide ring 76 is a planar holding surface 75a for holding 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 intervals of 30° along a circle concentric with the outer circumference of the holding surface 75a (the inner circumference 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. If the diameter of the semiconductor wafer W is φ300 mm, the diameter of the circle of the substrate support pins 77 is φ270 mm to φ280 mm (φ270 mm in this embodiment). Each substrate support pin 77 is formed of quartz. The plurality of substrate support pins 77 can be provided on the upper surface of the holding plate 75 by welding, or can be processed integrally with the holding plate 75.

[0072] return Figure 2The four connecting portions 72 erected on the base ring 71 and the peripheral edge of the retaining plate 75 of the base 74 are fixed by welding. Specifically, the base 74 and the base ring 71 are fixedly connected via the connecting portions 72. The base ring 71 of the retaining unit 7 is supported by the wall of the chamber 6, thereby attaching the retaining unit 7 to the chamber 6. When the retaining unit 7 is attached to the chamber 6, the retaining plate 75 of the base 74 is in a horizontal position (with its normal aligned with the vertical direction). Specifically, the retaining surface 75a of the retaining plate 75 is horizontal.

[0073] The semiconductor wafer W loaded into the chamber 6 is placed and held in a horizontal position on a susceptor 74 attached to the holding portion 7 of the chamber 6. At this time, the semiconductor wafer W is supported and held on the susceptor 74 by twelve substrate support pins 77 erected on the holding plate 75. 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. Since the height 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) is uniform, the twelve substrate support pins 77 can support the semiconductor wafer W in a horizontal position.

[0074] The semiconductor wafer W is supported by the 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 horizontal positional deviation of the semiconductor wafer W supported by the plurality of substrate support pins 77.

[0075] In addition, if Figure 2 as well as Figure 3 As shown, an opening portion 78 is formed in the holding plate 75 of the base 74 and passes through it from top to bottom. The opening portion 78 is provided so that the back-side radiation thermometer 20 can receive the radiation light (infrared light) radiated from the lower surface of the semiconductor wafer W. That is, the back-side radiation thermometer 20 receives the light radiated from the lower surface of the semiconductor wafer W through the opening portion 78 and the transparent window 21 installed in the through hole 61b of the chamber side portion 61 to measure the temperature of the semiconductor wafer W. In addition, four through holes 79 are provided through the holding plate 75 of the base 74, and the lifting pins 12 of the transfer mechanism 10 described later pass through the through holes 79 to transfer the semiconductor wafer W. In addition, in order to measure the in-plane temperature distribution of the semiconductor wafer W, a plurality of back-side radiation thermometers 20 can also be provided. In the case where a plurality of back-side radiation thermometers 20 are provided, a plurality of opening portions 78 are also required.

[0076] Figure 5 : is a top view of the transfer mechanism 10. Figure 6: This is a side view of the transfer mechanism 10. The transfer mechanism 10 has two transfer arms 11. The transfer arms 11 are roughly in the shape of an arc along the annular recess 62. Two lifting pins 12 are vertically provided on each transfer arm 11. The transfer arm 11 and the lifting pins 12 are formed of quartz. Each transfer arm 11 can be rotated by a horizontal moving mechanism 13. The horizontal moving mechanism 13 can move a pair of transfer arms 11 in a transfer operation position ( Figure 5 The solid line position) and the retracted position ( Figure 5 As the horizontal moving mechanism 13, each transfer arm 11 can be rotated by a respective motor, or a link mechanism can be used and a pair of transfer arms 11 can be rotated in conjunction with one motor.

[0077] In addition, the pair of transfer arms 11 are moved up and down together with the horizontal moving 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 the through holes 79 (see FIG. Figure 2 、 3 ), the upper end of the lifting pin 12 protrudes from the upper surface of the base 74. On the other hand, the lifting mechanism 14 lowers the pair of transfer arms 11 in the transfer action position, so that the lifting pin 12 is pulled out from the through hole 79, and when the horizontal moving mechanism 13 moves the pair of transfer arms 11 in an open manner, each transfer arm 11 moves to the retreat position. The retreat position of the pair of transfer arms 11 is directly above the base ring 71 of the retaining portion 7. Since the base ring 71 is placed on the bottom surface of the recess 62, the retreat position of the transfer arm 11 is on the inner side of the recess 62. In addition, an exhaust mechanism (not shown) is also provided near the location where the drive portion (horizontal moving mechanism 13 and lifting mechanism 14) of the transfer mechanism 10 is provided, and the exhaust mechanism discharges the ambient gas around the drive portion of the transfer mechanism 10 to the outside of the chamber 6.

[0078] Return to Figure 1 The flash heating unit 5, located above the chamber 6, has a light source composed of multiple (30 in this embodiment) xenon flash lamps FL and a reflector 52 provided inside a frame 51 to cover the light source. Furthermore, a light radiation window 53 is attached to the bottom of the frame 51 of the flash heating unit 5. The light radiation window 53 forming the bottom of the flash heating unit 5 is a plate-shaped quartz window made of quartz. By placing the flash heating unit 5 above the chamber 6, the light radiation window 53 faces the upper chamber window 63. The flash lamp FL irradiates the heat treatment space 65 with flash light from above the chamber 6 through the light radiation window 53 and the upper chamber window 63.

[0079] The flash lamps FL are long cylindrical rod-shaped lamps arranged in a plane with their longitudinal directions parallel to each other along the main surface (i.e., in the horizontal direction) of the semiconductor wafer W held by the holding portion 7. Therefore, the plane formed by the arrangement of the flash lamps FL is also a horizontal plane.

[0080] A xenon flash lamp FL consists of a rod-shaped glass tube (discharge tube) enclosed in xenon gas, with an anode and cathode connected to a capacitor at each end, and a trigger electrode attached to the outer circumference of the glass tube. Because xenon gas is an electrical insulator, no current flows through the glass tube under normal conditions, even if charge accumulates in the capacitor. However, when a high voltage is applied to the trigger electrode, breaking the insulation, the charge accumulated in the capacitor instantly flows into the glass tube, exciting xenon atoms or molecules at this time and emitting light. In this xenon flash lamp FL, the electrostatic energy previously accumulated in the capacitor is converted into extremely short light pulses, ranging from 0.1 to 100 milliseconds. This allows it to emit extremely intense light compared to continuously lit light sources like halogen lamps HL. In other words, the flash lamp FL is a pulsed light lamp that emits light instantaneously, within a very short time, less than one second. Furthermore, the flash lamp FL's light emission duration can be adjusted by adjusting the coil constant of the lamp power supply that supplies power to the flash lamp FL.

[0081] Furthermore, reflectors 52 are provided above the flash lamps FL so as to cover the entire flash lamps FL. The basic function of reflectors 52 is to reflect the flash light emitted from the flash lamps FL toward the heat treatment space 65. Reflectors 52 are formed from an aluminum alloy plate, and their surface (the surface facing the flash lamps FL) is roughened by sandblasting.

[0082] The halogen heating unit 4, located below the chamber 6, has a plurality (40 in this embodiment) of halogen lamps HL built into a 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.

[0083] Figure 7 It is a top view showing the configuration of multiple halogen lamps HL. 40 halogen lamps HL are arranged in two layers, upper and lower. 20 halogen lamps HL are arranged in the upper layer close to the holding part 7, and 20 halogen lamps HL are arranged in the lower layer farther away from the holding part 7 than the upper layer. Each halogen lamp HL is a rod-shaped lamp with a long cylindrical shape. In the upper and lower layers, the 20 halogen lamps HL are arranged so that their respective length directions are parallel to each other along the main surface of the semiconductor chip W held by the holding part 7 (i.e., along the horizontal direction). As a result, in the upper and lower layers, the planes formed by the arrangement of the halogen lamps HL are both horizontal planes.

[0084] In addition, if Figure 7 As shown, in both the upper and lower layers, the halogen lamps HL are arranged at a higher density in the area facing the periphery of the semiconductor wafer W held by the holding portion 7 than in the area facing the center. In other words, in both the upper and lower layers, the spacing between the halogen lamps HL in the periphery is shorter than in the center of the arrangement. Therefore, when heating with light emitted by the halogen heating unit 4, a greater amount of light can be irradiated toward the periphery of the semiconductor wafer W, where the temperature is more likely to drop.

[0085] The lamp group consisting of the halogen lamps HL in the upper layer and the lamp group consisting of the halogen lamps HL in the lower layer are arranged in a lattice pattern. That is, the longitudinal directions of the 20 halogen lamps HL arranged in the upper layer and the longitudinal directions of the 20 halogen lamps HL arranged in the lower layer are perpendicular to each other, for a total of 40 halogen lamps HL.

[0086] The halogen lamp HL is a filament-type light source that turns the filament inside a glass tube into an incandescent state and emits light by energizing the filament. A gas in which a small amount of halogen elements (iodine, bromine, etc.) are introduced into an inert gas such as nitrogen or argon is sealed inside the glass tube. By introducing the halogen elements, the breakage of the filament can be suppressed, and the temperature of the filament can be set to a high temperature. Therefore, compared with ordinary incandescent lamps, the halogen lamp HL has the characteristics of a long life and the ability to continuously irradiate strong light. In other words, the halogen lamp HL is a continuously lit lamp that emits light continuously for at least 1 second. In addition, because the halogen lamp HL is a rod-shaped lamp with a long life, by arranging the halogen lamp HL in the horizontal direction, the efficiency of radiating to the semiconductor chip W above is excellent.

[0087] In addition, a reflector 43 ( Figure 1 The reflector 43 reflects the light emitted from the plurality of halogen lamps HL toward the heat treatment space 65 .

[0088] like Figure 1 As shown, two radiation thermometers, namely a front-side radiation thermometer 25 and a back-side radiation thermometer 20 , are installed in the chamber 6 . Figure 8This is a functional block diagram showing the front-side radiation thermometer 25 and the back-side radiation thermometer 20. The front-side radiation thermometer 25, located obliquely above the semiconductor wafer W held by the susceptor 74, measures the temperature of the top surface of the semiconductor wafer W. The front-side radiation thermometer 25 comprises an infrared sensor 29, an amplifier 28, and a temperature measurement unit 27. The infrared sensor 29 receives infrared light radiated from the top surface of the semiconductor wafer W held by the susceptor 74. The infrared sensor 29 comprises an InSb (indium antimonide) optical element to accommodate the rapid temperature changes of the top surface of the semiconductor wafer W at the moment of exposure to the flash. The infrared sensor 29 transmits a signal generated in response to the received light to the amplifier 28. The signal output from the infrared sensor 29 is amplified by the amplifier 28 and then input to the temperature measurement unit 27. The temperature measurement unit 27 comprises an A / D converter and a temperature conversion circuit (not shown) and converts the signal indicating the intensity of the infrared light output from the infrared sensor 29 into a temperature. The temperature measured by the temperature measurement unit 27 represents the temperature of the top surface of the semiconductor wafer W.

[0089] On the other hand, the back-side radiation thermometer 20, which is provided obliquely below the semiconductor wafer W held by the susceptor 74, measures the temperature of the lower surface of the semiconductor wafer W. The back-side radiation thermometer 20 includes an infrared sensor 24, an amplifier 23, and a temperature measurement unit 22. The infrared sensor 24 receives infrared light radiated from the lower surface of the semiconductor wafer W held by the susceptor 74 through the opening 78. The infrared sensor 24 transmits a signal generated in response to the received light to the amplifier 23. The signal output from the infrared sensor 24 is amplified by the amplifier 23 and then input to the temperature measurement unit 22. The temperature measurement unit 22 includes an A / D converter and a temperature conversion circuit (not shown), and converts the signal indicating the intensity of the infrared light output from the infrared sensor 24 into a temperature. The temperature obtained by the temperature measurement unit 22 is the temperature of the lower surface of the semiconductor wafer W.

[0090] In addition, a cooling element 95 is attached to the infrared sensor 29 of the surface-side radiation thermometer 25. As the cooling element 95, a Peltier element is used, for example. The cooling element 95 is electrically connected to a power control unit 96. The power supplied to the cooling element 95 is controlled by the power control unit 96, and the cooling element 95 cools the light receiving element of the infrared sensor 29 to below 0°C. In this embodiment, for example, the light receiving element of the infrared sensor 29 is cooled to -25°C. The detection sensitivity of the InSb light receiving element of the infrared sensor 29 decreases as the temperature rises, but by cooling the light receiving element to below 0°C using the cooling element 95, the infrared sensor 29 can maintain high sensitivity.

[0091] The backside radiation thermometer 20 and the frontside radiation thermometer 25 are electrically connected to the control unit 3, which serves as the overall controller for the heat treatment apparatus 1. The temperatures of the lower and upper surfaces of the semiconductor wafer W, respectively measured by the backside radiation thermometer 20 and the frontside radiation thermometer 25, are transmitted to the control unit 3. The control unit 3 controls the various operating mechanisms provided in the heat treatment apparatus 1. The hardware structure of the control unit 3 is similar to that of a general computer. Specifically, the control unit 3 includes a CPU, which is a circuit that performs various calculations; a read-only memory, which is a ROM, that stores basic programs; a freely readable and writable RAM, which stores various information; and a magnetic disk that stores control software and data. The processing in the heat treatment apparatus 1 is performed by the CPU of the control unit 3 executing a predetermined processing program.

[0092] In addition to the above-mentioned structure, the heat treatment device 1 is also equipped with various cooling structures for preventing the temperature of the halogen heating part 4, the flash heating part 5 and the chamber 6 from excessively rising due to the heat energy generated by the halogen lamp HL and the flash lamp FL when heat treating the semiconductor wafer W. For example, a water cooling pipe (not shown) is provided on the wall of the chamber 6. By supplying cooling water to the water cooling pipe from the outside of the heat treatment device 1, the wall surface of the chamber 6 is cooled. In addition, the halogen heating part 4 and the flash heating part 5 are provided with an air cooling structure inside to form an air flow and discharge heat. In addition, air is also supplied to the gap between the upper chamber window 63 and the lamp radiation window 53 to cool the flash heating part 5 and the upper chamber window 63.

[0093] Next, the processing operations in the heat treatment apparatus 1 will be described. First, the heat treatment operations performed on a typical semiconductor wafer (product wafer) W, which will become a product, will be described. The processing sequence of the semiconductor wafer W described below is performed by the controller 3 controlling the various operating mechanisms of the heat treatment apparatus 1.

[0094] First, before processing the semiconductor wafer W, the gas supply valve 84 is opened, and the exhaust valve 89 is opened to start supplying and exhausting the chamber 6. When the valve 84 is opened, nitrogen gas is supplied from the gas supply hole 81 to the heat treatment space 65. 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 portion of the heat treatment space 65 in the chamber 6 flows downward and is exhausted from the lower portion of the heat treatment space 65.

[0095] Furthermore, by opening valve 192, the gas in chamber 6 is exhausted from transfer opening 66. Furthermore, an exhaust mechanism (not shown) is used to exhaust the atmosphere around the drive unit of transfer mechanism 10. Furthermore, during heat treatment of semiconductor wafers W in heat treatment apparatus 1, nitrogen gas is continuously supplied to heat treatment space 65, and the supply amount is appropriately changed depending on the treatment process.

[0096] Next, gate valve 185 is opened to open transfer opening 66, and a transfer robot outside the apparatus transfers the semiconductor wafer W, to be processed, into heat treatment space 65 within chamber 6 through transfer opening 66. At this time, there is a concern that ambient air from outside the apparatus may be introduced as the semiconductor wafer W is brought in. However, since nitrogen gas is continuously supplied to chamber 6, nitrogen gas flows out of transfer opening 66, minimizing the introduction of such ambient air.

[0097] The semiconductor wafer W loaded by the transport robot enters the position directly above the holding portion 7 and stops. 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 base 74 to receive the semiconductor wafer W. At this time, the lift pins 12 rise to above the upper ends of the substrate support pins 77.

[0098] After the semiconductor wafer W is placed on the lifting pins 12, the transport robot withdraws from the heat treatment space 65 and the transport opening 66 is closed by the gate valve 185. Then, the pair of transfer arms 11 descends, so that the semiconductor wafer W is transferred from the transfer mechanism 10 to the base 74 of the holding portion 7 and is held in a horizontal position from below. The semiconductor wafer W is supported and held on the base 74 by a plurality of substrate support pins 77 erected on the holding plate 75. In addition, the semiconductor wafer W is held on the holding portion 7 with the surface to be processed as the upper surface. A predetermined gap is formed between the back side (the main surface opposite to the 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 have descended to the bottom of the base 74 are retreated by the horizontal moving mechanism 13 to the retreat position, that is, the inner side of the recess 62.

[0099] After the semiconductor wafer W is held in a horizontal position from below by the base 74 of the holding portion 7 formed of quartz, the 40 halogen lamps HL of the halogen heating portion 4 are lit together to begin preheating (auxiliary heating). The halogen light emitted from the halogen lamps HL passes through the lower chamber window 64 formed of quartz and the base 74, and irradiates the lower surface of the semiconductor wafer W. By receiving the light irradiation from the halogen lamps HL, the semiconductor wafer W is preheated and the temperature rises. In addition, since the transfer arm 11 of the transfer mechanism 10 retreats to the inside of the recess 62, it does not hinder the heating of the halogen lamps HL.

[0100] The temperature of the semiconductor wafer W, which has been heated by light irradiation from the halogen lamp HL, is measured by the back-side radiation thermometer 20. The measured temperature of the semiconductor wafer W is transmitted to the control unit 3. The control unit 3 monitors whether the temperature of the semiconductor wafer W, which has been heated by light irradiation from the halogen lamp HL, has reached the predetermined preheating temperature T1 and controls the output of the halogen lamp HL. Specifically, the control unit 3 performs feedback control of the output of the halogen lamp HL based on the measurement value of the back-side radiation thermometer 20 so that the temperature of the semiconductor wafer W reaches the preheating temperature T1.

[0101] 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 back side radiation thermometer 20 reaches the preheating temperature T1, the control unit 3 adjusts the output of the halogen lamp HL to maintain the temperature of the semiconductor wafer W approximately at the preheating temperature T1.

[0102] By preheating with these halogen lamps HL, the entire semiconductor wafer W is uniformly heated to the preheating temperature T1. During the preheating phase with the halogen lamps HL, the temperature of the peripheral portion of the semiconductor wafer W, where heat dissipation is more effective, tends to drop below that of the central portion. However, the halogen lamps HL are arranged more densely in the halogen heating unit 4, facing the peripheral portion, rather than the central portion. This increases the amount of light irradiated toward the peripheral portion of the semiconductor wafer W, where heat dissipation is more effective, thereby achieving a more uniform in-plane temperature distribution across the semiconductor wafer W during the preheating phase.

[0103] When the temperature of the semiconductor wafer W reaches the preheating temperature T1 and a predetermined time has elapsed, the flash lamp FL of the flash heating unit 5 flash-irradiates the surface of the semiconductor wafer W held by the susceptor 74. At this time, a portion of the flash light radiated from the flash lamp FL directly irradiates the chamber 6, while the remaining portion is reflected by the reflector 52 and then irradiates the chamber 6. Through this flash light irradiation, the semiconductor wafer W is flash-heated.

[0104] Flash heating is performed using flash irradiation from the flash lamp FL, thereby rapidly increasing the surface temperature of the semiconductor wafer W. Specifically, the flash irradiation from the flash lamp FL is an extremely short, intense flash of light with an irradiation time of approximately 0.1 milliseconds to 100 milliseconds, converting electrostatic energy previously stored in a capacitor into an extremely short light pulse. Furthermore, the surface temperature of the semiconductor wafer W flash-heated by the flash irradiation from the flash lamp FL instantly rises to a processing temperature T2 exceeding 1000°C, then rapidly decreases.

[0105] After the flash heating process is completed, the halogen lamp HL turns off after a predetermined period of time. This allows the semiconductor wafer W to rapidly cool down from the preheating temperature T1. The temperature of the semiconductor wafer W during cooling is measured by the back-side radiation thermometer 20, and the measurement result is transmitted to the control unit 3. Based on the measurement result of the back-side radiation thermometer 20, the control unit 3 monitors whether the temperature of the semiconductor wafer W has fallen to the predetermined temperature. After the temperature of the semiconductor wafer W drops below the predetermined temperature, the pair of transfer arms 11 of the transfer mechanism 10 horizontally move from the retracted position to the transfer operation position and rise. The lift pins 12 protrude from the upper surface of the base 74 and receive the heat-treated semiconductor wafer W from the base 74. Next, the transfer opening 66, which was 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 outside the apparatus, thereby completing the heating process of the semiconductor wafer W.

[0106] The surface temperature of the semiconductor wafer W, which instantly heats up during flash heating, is measured by the surface-side radiation thermometer 25. Furthermore, the surface of the semiconductor wafer W, which will become a finished product, is often patterned. The surface emissivity of the semiconductor wafer W also varies depending on the pattern formed. Therefore, unless the surface emissivity of each semiconductor wafer W heated in the heat treatment apparatus 1 is calculated and set in the surface-side radiation thermometer 25, it is impossible to accurately measure the surface temperature of the semiconductor wafer W. In this embodiment, the surface temperature of the semiconductor wafer W is accurately measured using the following method.

[0107] Figure 9 : is a flowchart showing the sequence of the temperature measurement method of the present invention. First, before processing the semiconductor wafer W to become a product, the wafer (first substrate) TW with a thermocouple is moved into the chamber 6 (step S1). The wafer TW with a thermocouple is a silicon wafer in the same circular plate shape as the semiconductor wafer W to become a product, and has the same size and shape as the semiconductor wafer W. However, pattern formation and film formation are not performed on the wafer TW with a thermocouple. In addition, a thermocouple is installed on the surface of the wafer TW with a thermocouple. Since the thermocouple is composed of a metal wire, the wafer TW with a thermocouple cannot be moved into the chamber 6 by a transport robot. Therefore, the wafer TW with a thermocouple is manually moved into the chamber 6 and placed on the base 74.

[0108] After the wafer TW with thermocouples is placed on the quartz susceptor 74, light irradiation from the halogen lamp HL begins to heat the wafer TW with thermocouples (step S2). Heating the wafer TW with thermocouples by light irradiation from the halogen lamp HL is substantially similar to the preheating of the semiconductor wafer W described above. Specifically, light emitted from the halogen lamp HL passes through the lower chamber window 64 and the susceptor 74 formed of quartz and irradiates the back surface of the wafer TW with thermocouples, thereby raising the temperature of the wafer TW with thermocouples. The temperature of the wafer TW with thermocouples, increased by light irradiation from the halogen lamp HL, is measured by the backside radiation thermometer 20. Based on the temperature measured by the backside radiation thermometer 20, the control unit 3 performs feedback control of the output of the halogen lamp HL to maintain the temperature of the wafer TW with thermocouples at a predetermined temperature. After the temperature of the wafer TW with thermocouples reaches the predetermined temperature, light irradiation from the halogen lamp HL maintains the wafer TW at that predetermined temperature for a predetermined period of time.

[0109] While the temperature of the wafer TW with thermocouples is maintained at a predetermined temperature, emissivity calibration of the backside radiation thermometer 20 is performed based on the measurement value of the thermocouples (step S3 ). Figure 10 This diagram schematically illustrates the emissivity correction of the backside radiation thermometer 20 based on the measurement value of the thermocouple 99. A wafer TW with thermocouples is maintained at a predetermined temperature for a predetermined period of time by irradiation with light from a halogen lamp HL. Thermocouples 99 are attached to the surface of the wafer TW with thermocouples. The temperature of the surface of the wafer TW with thermocouples, heated to the predetermined temperature by irradiation with light from the halogen lamp HL, is measured by the thermocouples 99.

[0110] Meanwhile, the temperature of the back surface of the wafer TW with thermocouples, heated to a predetermined temperature by light irradiation from the halogen lamp HL, is measured by the back surface radiation thermometer 20. The attachment position of the thermocouples 99 on the surface of the wafer TW with thermocouples and the temperature measurement position of the back surface radiation thermometer 20 on the back surface of the wafer TW with thermocouples are symmetrically positioned with respect to the wafer TW with thermocouples. Furthermore, when the wafer TW with thermocouples is maintained at a predetermined temperature, there is no temperature difference between the surface and back surface of the wafer TW with thermocouples, and the surface and back surface temperatures are equal. Consequently, the temperature at the attachment position of the thermocouples 99 on the surface of the wafer TW with thermocouples and the temperature at the back surface radiation thermometer 20 on the back surface of the wafer TW with thermocouples are completely equal.

[0111] The thermocouple 99, a contact thermometer, can accurately measure the surface temperature of the wafer TW with thermocouples. Therefore, the emissivity set by the backside radiation thermometer 20 can be corrected based on the temperature of the wafer TW with thermocouples measured by the thermocouple 99. Specifically, the emissivity set by the backside radiation thermometer 20 is adjusted so that the surface temperature of the wafer TW with thermocouples measured by the thermocouple 99 matches the backside temperature of the wafer TW with thermocouples as measured by the backside radiation thermometer 20. Thus, the true emissivity of the backside of the wafer TW with thermocouples is set by the backside radiation thermometer 20, allowing the emissivity set by the backside radiation thermometer 20 to be accurately corrected.

[0112] After the emissivity calibration of the back-side radiation thermometer 20 is completed, the wafer TW with thermocouples is unloaded from the chamber 6. Unloading of the wafer TW with thermocouples is also performed manually. The emissivity calibration of the wafer TW with thermocouples using the back-side radiation thermometer 20 described above can be performed, for example, during maintenance of the heat treatment apparatus 1.

[0113] Next, the semiconductor wafer (second substrate) W, which will become the product, is heat treated. Typically, a pattern is formed on the surface of the semiconductor wafer W, which will become the product. The heat treatment operation for the semiconductor wafer W, which will become the product, is as described above. First, the semiconductor wafer W, which will become the product, is loaded into the chamber 6 (step S4). The semiconductor wafer W is loaded into the chamber 6 by the transport robot and placed on the susceptor 74.

[0114] After the semiconductor wafer W is placed on the quartz susceptor 74, light irradiation from the halogen lamp HL begins to preheat the semiconductor wafer W (step S5). As described above, the temperature of the semiconductor wafer W, which has risen due to the light irradiation from the halogen lamp HL, is measured by the back-side radiation thermometer 20. Based on the temperature measured by the back-side radiation thermometer 20, the control unit 3 performs feedback control of the output of the halogen lamp HL so that the temperature of the semiconductor wafer W reaches a predetermined preheating temperature T1. After the temperature of the semiconductor wafer W reaches the preheating temperature T1, the light irradiation from the halogen lamp HL maintains the semiconductor wafer W at the preheating temperature T1 for a predetermined period of time.

[0115] While the temperature of the semiconductor wafer W is maintained at the preheating temperature T1 , the emissivity correction of the front-side radiation thermometer 25 is performed based on the measurement value of the back-side radiation thermometer 20 (step S6 ). Figure 11This diagram schematically illustrates the emissivity correction of the front-side radiation thermometer 25 based on the measurement values of the back-side radiation thermometer 20. A semiconductor wafer W is maintained at a preheating temperature T1 for a predetermined period of time by irradiation with light from a halogen lamp HL. The temperature of the back side of the semiconductor wafer W, heated to the preheating temperature T1 by the irradiation with light from the halogen lamp HL, is measured by the back-side radiation thermometer 20. Even finished semiconductor wafers W do not have a pattern formed on their back sides, as with the wafer TW with thermocouples. Therefore, the emissivity of the back side of the wafer TW with thermocouples is equal to that of the semiconductor wafer W. In step S3, the emissivity of the back side of the wafer TW with thermocouples is set in the back-side radiation thermometer 20, completing the emissivity correction of the back side radiation thermometer 20. Consequently, the back side radiation thermometer 20 can accurately measure the temperature of the back side of the semiconductor wafer W, which has the same emissivity as the back side of the wafer TW with thermocouples.

[0116] Meanwhile, the temperature of the surface of the semiconductor wafer W, heated to the preheating temperature T1 by irradiation with light from the halogen lamp HL, is measured by the surface-side radiation thermometer 25. The temperature measurement position of the surface-side radiation thermometer 25 on the surface of the semiconductor wafer W and the temperature measurement position of the back-side radiation thermometer 20 on the back surface of the semiconductor wafer W are symmetrical with respect to the semiconductor wafer W. Furthermore, when the semiconductor wafer W is maintained at the preheating temperature T1, there is no temperature difference between the surface and back surfaces of the semiconductor wafer W, and the surface and back surface temperatures are equal. Consequently, the temperature at the temperature measurement position of the surface-side radiation thermometer 25 on the surface of the semiconductor wafer W and the temperature at the back-side radiation thermometer 20 on the back surface of the semiconductor wafer W are completely equal.

[0117] As described above, the backside radiation thermometer 20 can accurately measure the backside temperature of the semiconductor wafer W. Therefore, the emissivity set at the frontside radiation thermometer 25 is corrected based on the temperature of the semiconductor wafer W measured by the backside radiation thermometer 20. Specifically, the emissivity set at the frontside radiation thermometer 25 is adjusted so that the backside temperature of the semiconductor wafer W indicated by the backside radiation thermometer 20 matches the surface temperature of the semiconductor wafer W indicated by the frontside radiation thermometer 25. Thus, by setting the emissivity of the surface of the semiconductor wafer W to be processed at the frontside radiation thermometer 25, the emissivity set at the frontside radiation thermometer 25 can be accurately corrected.

[0118] After the emissivity calibration of the surface-side radiation thermometer 25 is completed, flash lamp FL irradiates the surface of the semiconductor wafer W (step S7). By irradiating the surface of the semiconductor wafer W with a flash of light for a duration of 0.1 milliseconds to 100 milliseconds, the surface temperature of the semiconductor wafer W is instantly raised and then rapidly lowered.

[0119] The surface temperature of the semiconductor wafer W heated by the flash irradiation is measured by the surface-side radiation thermometer 25, which has undergone emissivity calibration (step S8). Because the surface-side radiation thermometer 25 includes an InSb light-receiving element, it can accurately measure the surface temperature of the semiconductor wafer W, which rapidly changes due to the flash irradiation, with a short sampling period. Furthermore, before the flash irradiation, the surface-side radiation thermometer 25 is set to the emissivity of the surface of the patterned semiconductor wafer W, thereby completing the emissivity calibration. Therefore, the surface-side radiation thermometer 25 can accurately measure the surface temperature of the semiconductor wafer W heated by the flash irradiation.

[0120] In this embodiment, a wafer TW with thermocouples 99 attached to its surface is heated by light irradiation from a halogen lamp HL, and the surface temperature of the wafer TW is measured by the thermocouples 99, while the back surface temperature is measured by the back surface radiation thermometer 20. Then, based on the temperature of the wafer TW with thermocouples measured by the thermocouples 99, the emissivity set in the back surface radiation thermometer 20 is corrected.

[0121] Next, after the emissivity calibration of the backside radiation thermometer 20 is completed, the semiconductor wafer W having a pattern formed on its surface is heated by light irradiation from the halogen lamp HL, and the temperatures of the backside and surface of the semiconductor wafer W are measured by the backside radiation thermometer 20 and the surface radiation thermometer 25, respectively. Then, based on the temperature of the semiconductor wafer W measured by the backside radiation thermometer 20, the emissivity set for the surface radiation thermometer 25 is calibrated.

[0122] In summary, the emissivity set for the backside radiation thermometer 20 and the frontside radiation thermometer 25 is corrected in two stages based on the accurate temperature measurement value obtained by the thermocouple 99, which functions as a contact thermometer. Therefore, even if the emissivity of both the front and back surfaces of the semiconductor wafer W is unknown, the emissivity set for the backside radiation thermometer 20 and the frontside radiation thermometer 25 can be appropriately corrected, allowing the frontside radiation thermometer 25 to accurately measure the surface temperature of the semiconductor wafer W. Furthermore, since no object comes into contact with the surface of the finished semiconductor wafer W, the surface temperature can be accurately measured without damaging the pattern formed on the surface of the semiconductor wafer W.

[0123] Furthermore, when calibrating the emissivity of the back-side radiation thermometer 20, while the wafer TW with thermocouples is maintained at a predetermined temperature by irradiation with light from the halogen lamp HL, the temperature of the wafer TW with thermocouples is measured by the thermocouple 99 and the back-side radiation thermometer 20. Therefore, there is no temperature difference between the front and back surfaces of the wafer TW with thermocouples, and the emissivity set by the back-side radiation thermometer 20 can be accurately calibrated based on the temperature measurement value of the thermocouple 99.

[0124] Similarly, when calibrating the emissivity of the front-side radiation thermometer 25, the temperature of the semiconductor wafer W is measured by the back-side radiation thermometer 20 and the front-side radiation thermometer 25 while the semiconductor wafer W is maintained at a predetermined temperature by irradiation with light from the halogen lamp HL. Therefore, there is no temperature difference between the front and back surfaces of the semiconductor wafer W, and the emissivity set for the front-side radiation thermometer 25 can be accurately calibrated based on the temperature measurement value of the back-side radiation thermometer 20.

[0125] Furthermore, the attachment position of the thermocouple 99 on the surface of the wafer TW with thermocouples and the temperature measurement position of the backside radiation thermometer 20 on the backside of the wafer TW with thermocouples are symmetrical with respect to the wafer TW with thermocouples. This eliminates any temperature difference between them, and the emissivity set for the backside radiation thermometer 20 can be more accurately corrected based on the temperature measurement value of the thermocouple 99.

[0126] Similarly, the temperature measurement position of the front-side radiation thermometer 25 on the front surface of the semiconductor wafer W and the temperature measurement position of the back-side radiation thermometer 20 on the back surface of the semiconductor wafer W are symmetrical with respect to the semiconductor wafer W. Thus, there is no temperature difference between them, and the emissivity set for the front-side radiation thermometer 25 can be corrected more accurately based on the temperature measurement value of the back-side radiation thermometer 20.

[0127] Furthermore, when the surface temperature of the semiconductor wafer W is measured using the surface-side radiation thermometer 25, the light-receiving element of the surface-side radiation thermometer 25 is cooled to below 0° C. using the cooling element 95. This allows the infrared sensor 29 of the surface-side radiation thermometer 25 to maintain high sensitivity, and enables the surface-side radiation thermometer 25 to accurately measure the temperature of the surface of the semiconductor wafer W heated by the flash irradiation.

[0128] Furthermore, in this embodiment, a water-cooling pipe is provided in the wall of the chamber 6, and cooling water is supplied to the water-cooling pipe, thereby cooling the wall surface of the chamber 6. This can suppress the influence of infrared light (stray light) radiated from the wall surface of the chamber 6 and incident on the back-side radiation thermometer 20 and the front-side radiation thermometer 25, thereby preventing a decrease in the accuracy of temperature measurement.

[0129] While the embodiments of the present invention have been described above, various modifications other than those described above are possible without departing from the spirit of the present invention. For example, in the above embodiment, the surface temperature of the wafer TW with the thermocouple is measured using the thermocouple 99. However, this is not limiting. Other contact thermometers, such as thermistors or resistance temperature detectors, may also be used for measurement. In other words, any method that accurately measures the surface temperature of the wafer TW with the thermocouple using a contact thermometer will suffice.

[0130] Furthermore, a polarization filter may be provided not only on the wall surface of the cooling chamber 6 but also on the surface of the cooling chamber 6 to suppress stray light from entering the backside radiation thermometer 20 and the frontside radiation thermometer 25. This can more effectively prevent a decrease in the accuracy of temperature measurement.

[0131] Furthermore, as the back-side radiation thermometer 20, it is preferable to use one having a measurement wavelength range appropriate to the ambient air formed within chamber 6. For example, if an ammonia atmosphere is formed within chamber 6, it is preferable to use a back-side radiation thermometer 20 having a measurement wavelength range different from the ammonia absorption wavelength range. Alternatively, a filter that transmits or blocks light in an appropriate wavelength range may be provided depending on the measurement target.

[0132] Furthermore, in the above-described embodiment, the infrared sensor 29 built into the front-side radiation thermometer 25 includes an InSb (indium antimonide) optical element to accommodate the rapid temperature change on the upper surface of the semiconductor wafer W at the moment of exposure to the flash. However, this is not limiting, and the infrared sensor 29 can be any sensor. For example, to measure the in-plane temperature distribution of the semiconductor wafer W during heating by light irradiation from the halogen heater 4, the infrared sensor 29 can also be a low-response sensor such as a thermopile. Furthermore, multiple front-side radiation thermometers 25 may be provided. This eliminates the need for multiple back-side radiation thermometers 20 for measuring the in-plane temperature distribution of the semiconductor wafer W and the need for the openings 78 for receiving the radiant light (infrared light) emitted from the lower surface of the semiconductor wafer W. This prevents the degradation of the in-plane temperature uniformity of the semiconductor wafer W during heating, which could be caused by the degradation of the uniformity of light irradiation from the halogen heater 4 due to the provision of multiple openings 78.

[0133] In the above embodiment, the flash heating unit 5 includes 30 flash lamps FL, but this is not limited to this. The number of flash lamps FL may be any number. Furthermore, the flash lamps FL are not limited to xenon flash lamps and may also be krypton flash lamps. Furthermore, the number of halogen lamps HL included in the halogen heating unit 4 is not limited to 40 and may be any number.

[0134] In addition, in the above-mentioned embodiment, a filament-type halogen lamp HL is used as a continuous lighting lamp that continuously emits light for more than 1 second to perform a heat treatment to maintain the substrate at a specified temperature, but this is not limited to this. A discharge-type arc lamp (for example, a xenon arc lamp) or an LED lamp can be used as a continuous lighting lamp instead of the halogen lamp HL for heat treatment.

Claims

1. A temperature measurement method for measuring the temperature of a substrate, wherein: include: a first calibration step of heating a first substrate having a contact thermometer mounted on its surface, measuring the temperature of the back surface of the first substrate using a back-side radiation thermometer, and calibrating the emissivity set in the back-side radiation thermometer based on the temperature of the first substrate measured by the contact thermometer; a second calibration step of heating a second substrate having a pattern formed on a surface thereof, measuring the temperatures of the back surface and the front surface of the second substrate using the back-side radiation thermometer and the front-side radiation thermometer, respectively, and calibrating the emissivity set in the front-side radiation thermometer based on the temperature of the second substrate measured by the back-side radiation thermometer; as well as In the temperature measurement step, the surface temperature of the second substrate heated by the light irradiation is measured using the surface-side radiation thermometer.

2. The temperature measurement method according to claim 1, wherein: In the first calibration step and the second calibration step, the first substrate and the second substrate are heated by irradiation with light from a continuously lighting lamp.

3. The temperature measurement method according to claim 2, wherein: In the first calibration step, while the first substrate is maintained at a predetermined temperature by irradiation with light from the continuously lighting lamp, the temperature of the first substrate is measured using the contact thermometer and the back-side radiation thermometer. In the second calibration step, while the second substrate is maintained at a predetermined temperature by irradiation with light from the continuously lighting lamp, the temperature of the second substrate is measured by the backside radiation thermometer and the frontside radiation thermometer.

4. The temperature measurement method according to claim 1, wherein: In the temperature measurement step, the surface temperature of the second substrate, which is increased when the flash light is irradiated from the flash lamp onto the surface of the second substrate, is measured using the surface-side radiation thermometer.

5. The temperature measurement method according to claim 1, wherein: The mounting position of the contact thermometer and the temperature measurement position of the back-side radiation thermometer are symmetrical with respect to the first substrate. The temperature measurement position of the rear-side radiation thermometer and the temperature measurement position of the front-side radiation thermometer are symmetrical with respect to the second substrate.

6. The temperature measurement method according to claim 1, wherein: When measuring the surface temperature of the second substrate, the light receiving element of the surface-side radiation thermometer is cooled to 0° C. or lower.

7. The temperature measurement method according to claim 1, wherein: A wall surface of a chamber accommodating the first substrate and the second substrate is cooled.

8. The temperature measurement method according to any one of claims 1 to 7, wherein: The contact thermometer is a thermocouple.

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