Heat treatment method and heat treatment device

Abstract

After the semiconductor wafer is preheated at the preheating temperature, a flash is irradiated from the flash lamp. The surface temperature of the semiconductor wafer heated by the flash irradiation is measured by the upper radiation thermometer. When the surface temperature of the semiconductor wafer measured by the upper radiation thermometer reaches the target temperature, the current supply to the flash lamp is stopped to cool the surface temperature of the semiconductor wafer. Since the current supply to the flash lamp is stopped when the measured surface temperature of the semiconductor wafer reaches the target temperature, the surface temperature of the semiconductor wafer can be accurately raised to the target temperature regardless of the surface state or reflectivity of the semiconductor wafer.

Description

Technical Field

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

[0002] In the manufacturing process of semiconductor devices, impurity introduction is a necessary step to form a pn junction in a semiconductor wafer. Currently, impurity introduction is usually completed by ion implantation and subsequent annealing. Ion implantation is a technology that physically implants impurities by ionizing impurity elements such as boron (B), arsenic (As), and phosphorus (P) and colliding them with a semiconductor wafer at a high acceleration voltage. The implanted impurities are activated by annealing. At this time, if the annealing time is more than a few seconds, the implanted impurities will diffuse deeper due to heat, resulting in a junction depth that is too deep than the required depth, which prevents the formation of a good device.

[0003] Therefore, as an annealing technology for heating semiconductor wafers in an extremely short time, flash lamp annealing (FLA) has attracted attention in recent years. Flash lamp annealing is a heat treatment technology that heats only the surface of the semiconductor wafer injected with impurities in an extremely short time (several milliseconds or less) by irradiating the surface of the semiconductor wafer with a flash of light using a xenon flash lamp (hereinafter, when simply referred to as a "flash lamp", it means a xenon flash lamp).

[0004] The radiation spectrum distribution of the xenon flash lamp is from the ultraviolet region to the near infrared region, and the wavelength is shorter than that of the previous halogen lamp, and is roughly consistent with the basic absorption band of the silicon semiconductor wafer. Therefore, when the semiconductor wafer is irradiated with a flash from the xenon flash lamp, less light is transmitted, and the temperature of the semiconductor wafer can be rapidly increased. In addition, it is also known that if the flash irradiation is performed for an extremely short time of less than a few milliseconds, it is possible to selectively increase the temperature only near the surface of the semiconductor wafer. Therefore, if the temperature is increased for an extremely short time using the xenon flash lamp, the impurities will not be diffused deeply, and only the impurity activation can be performed.

[0005] As a heat treatment device using such a xenon flash lamp, Patent Document 1 discloses a device in which an insulated gate bipolar transistor (IGBT) is connected to the light-emitting circuit of the flash lamp to control the light emission of the flash lamp. In the device disclosed in Patent Document 1, the light emission of the lamp can be controlled by inputting a predetermined pulse signal to the gate of the IGBT to define the waveform of the current flowing through the flash lamp, thereby freely adjusting the surface temperature distribution of the semiconductor wafer.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2009-070948 Summary of the invention

[0009] Problems to be solved by the invention

[0010] In the device disclosed in Patent Document 1, when flash heating is performed on a plurality of semiconductor wafers, if a pulse signal of the same pattern is input to the gate of the IGBT, the surface heating temperature of each semiconductor wafer should be the same. However, in reality, due to the difference in the surface state of the semiconductor wafer, even if the pulse signal of the same pattern is input to the gate of the IGBT, the surface reaching temperature (peak temperature) of the semiconductor wafer is uneven. The surface reaching temperature of the semiconductor wafer during flash heating directly contributes to the device performance, so if there is unevenness in the surface reaching temperature, there will be a problem that uniform device performance cannot be obtained.

[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 and a heat treatment apparatus which can accurately increase the surface temperature of a substrate to a target temperature.

[0012] [Methods of solving the problem]

[0013] In order to solve the above-mentioned problems, the invention of technical solution 1 is a heat treatment method, which heats the substrate by irradiating a flash on the substrate, and is characterized in that it comprises: a flash irradiation step, in which a flash is irradiated from a flash lamp to the surface of the substrate to increase the temperature of the surface; a temperature measurement step, in which the temperature of the above-mentioned surface of the heated substrate is measured by a radiation thermometer; and a light emission stopping step, in which when the temperature of the above-mentioned surface measured by the above-mentioned radiation thermometer reaches the target temperature, the current supply to the above-mentioned flash lamp is stopped to cool down the temperature of the above-mentioned surface.

[0014] In addition, the invention of technical solution 2 is a heat treatment method, which heats the substrate by irradiating a flash on the substrate, and is characterized in that it comprises: a flash irradiation step, in which a flash is irradiated from a flash lamp to the surface of the substrate to increase the temperature of the surface; a temperature measurement step, in which the temperature of the above-mentioned surface of the above-mentioned heated substrate is measured by a radiation thermometer; a prediction step, in which a predetermined time when the temperature of the above-mentioned surface reaches the target temperature is predicted based on the temperature measurement result of the above-mentioned radiation thermometer; and a light emission stopping step, in which the current supply to the above-mentioned flash lamp is stopped within a specified period including the above-mentioned predetermined time predicted in the above-mentioned prediction step to reduce the temperature of the above-mentioned surface.

[0015] In addition, the invention of technical solution 3 is a heat treatment method as the invention of technical solution 2, wherein, in the above-mentioned light emission stopping step, the current supply to the above-mentioned flash lamp is stopped when the above-mentioned predetermined time is reached.

[0016] The invention according to claim 4 is a heat treatment method according to claim 2 , wherein in the prediction step, the expected arrival time is predicted based on a plurality of temperature rise patterns obtained when the flash irradiation is performed.

[0017] In addition, the invention of claim 5 is a processing method as in any one of claims 1 to 4, wherein in the light emission stopping step, an IGBT connected to the flash lamp is turned off to stop supplying current to the flash lamp.

[0018] In addition, the invention of technical solution 6 is a heat treatment device, which heats the substrate by irradiating a flash on the substrate, and is characterized in that it comprises: a chamber that accommodates the substrate; a flash lamp that irradiates a flash on the surface of the substrate accommodated in the above-mentioned chamber to heat the surface; a radiation thermometer that measures the temperature of the above-mentioned surface of the heated substrate; and a switch part that stops the supply of current to the above-mentioned flash lamp to cool down the temperature of the above-mentioned surface when the temperature of the above-mentioned surface measured by the above-mentioned radiation thermometer reaches the target temperature.

[0019] In addition, the invention of technical solution 7 is a heat treatment device, which heats the substrate by irradiating a flash on the substrate, and is characterized in that it comprises: a chamber that accommodates the substrate; a flash lamp that irradiates a flash on the surface of the substrate accommodated in the above-mentioned chamber to heat the surface; a radiation thermometer that measures the temperature of the above-mentioned surface of the heated substrate; a prediction unit that predicts the scheduled time when the temperature of the above-mentioned surface reaches the target temperature based on the temperature measurement result of the above-mentioned radiation thermometer; and a switch unit that stops the supply of current to the above-mentioned flash lamp within a specified period including the above-mentioned scheduled time predicted by the above-mentioned prediction unit to cool down the temperature of the above-mentioned surface.

[0020] In addition, the invention according to claim 8 is a heat treatment device according to the invention according to claim 7 , wherein the switch section stops supplying current to the flash lamp when the predetermined timing is reached.

[0021] In addition, the invention of technical solution 9 is a heat treatment device as the invention of technical solution 7, which further includes a storage unit that stores multiple temperature rise patterns obtained during flash irradiation, and the above-mentioned prediction unit predicts the above-mentioned arrival predetermined time based on the above-mentioned multiple temperature rise patterns.

[0022] In addition, the invention according to claim 10 is a heat treatment device according to any one of claims 6 to 9, wherein the switch section includes an IGBT connected to the flash lamp.

[0023] [Effects of the invention]

[0024] According to the invention of technical solution 1, when the surface temperature of the substrate measured by the radiation thermometer reaches the target temperature, the current supply to the flash lamp is stopped to cool the surface temperature of the substrate. Therefore, regardless of the surface state of the substrate, the surface temperature of the substrate can be accurately raised to the target temperature.

[0025] According to the invention of technical solutions 2 to 5, the predetermined time when the surface temperature of the substrate reaches the target temperature is predicted based on the temperature measurement result of the self-radiation thermometer, and the current supply to the flash lamp is stopped within a specified period including the predetermined time to cool the surface temperature of the substrate. Therefore, regardless of the surface state of the substrate, the surface temperature of the substrate can be accurately raised to the target temperature.

[0026] According to the invention of technical solution 6, when the surface temperature of the substrate measured by the radiation thermometer reaches the target temperature, the current supply to the flash lamp is stopped to cool the surface temperature of the substrate. Therefore, regardless of the surface state of the substrate, the surface temperature of the substrate can be accurately raised to the target temperature.

[0027] According to the invention of technical solutions 7 to 10, the temperature measurement result of the radiation thermometer predicts the scheduled time when the surface temperature of the substrate reaches the target temperature, and the current supply to the flash lamp is stopped within a specified period including the scheduled time to cool the surface temperature of the substrate. Therefore, regardless of the surface state of the substrate, the surface temperature of the substrate can be accurately raised to the target temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a longitudinal sectional view showing the structure of the heat treatment apparatus of the present invention.

[0029] Figure 2 It is a perspective view showing the overall appearance of the holding portion.

[0030] Figure 3 This is a top view of the crystal seat.

[0031] Figure 4 It is a cross-sectional view of the crystal seat.

[0032] Figure 5 It is a top view of the transfer mechanism.

[0033] Figure 6 It is a side view of the transfer mechanism.

[0034] Figure 7 It is a top view showing the arrangement of a plurality of halogen lamps.

[0035] Figure 8 This is a diagram showing a driving circuit of a flash lamp.

[0036] Fig. 9This is a block diagram showing the configuration of a high-speed radiation thermometer unit including the main parts of the upper radiation thermometer.

[0037] Fig.10 This is a flowchart showing the processing procedure of the heat treatment apparatus according to the first embodiment.

[0038] Fig.11 This is a diagram showing changes in the surface temperature of a semiconductor wafer measured by an upper radiation thermometer.

[0039] Fig.12 This is a diagram showing an example of a waveform of a pulse signal.

[0040] Fig.13 This is a diagram showing changes in the current flowing through the flash lamp.

[0041] Fig.14 This is a flowchart showing the processing procedure of the heat treatment apparatus according to the second embodiment.

[0042] Fig.15 It is a diagram showing the change in the surface temperature of the semiconductor wafer according to the second embodiment. DETAILED DESCRIPTION

[0043] Below, refer to the attached Figure 1 Embodiments of the present invention will be described in detail.

[0044] <First embodiment>

[0045] Figure 1 It is a longitudinal sectional view showing the structure of the heat treatment apparatus 1 of the present invention. Figure 1 The heat treatment device 1 is a flash lamp annealing device that heats a semiconductor wafer W in the shape of a disk as a substrate by flash irradiating 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 the present embodiment). Impurities are injected into the semiconductor wafer W before being transported into the heat treatment device 1, and the injected impurities are activated by the heating treatment of the heat treatment device 1. In addition, Figure 1 In the drawings and the following drawings, the size or number of each component is exaggerated or simplified as necessary to facilitate understanding.

[0046] The heat treatment apparatus 1 includes: a chamber 6 that accommodates a semiconductor wafer W; a flash heating unit 5 that has a plurality of flash lamps FL built therein; and a halogen heating unit 4 that has a plurality of halogen lamps HL built therein. The flash heating unit 5 is provided on the upper side of the chamber 6, and the halogen heating unit 4 is provided on the lower side. In addition, the heat treatment apparatus 1 includes: a holding unit 7 that holds the semiconductor wafer W in a horizontal position inside the chamber 6; and a transfer mechanism 10 that transfers the semiconductor wafer W between the holding unit 7 and the outside of the apparatus. Furthermore, the heat treatment apparatus 1 includes a control unit 3 that controls each operating mechanism provided in the halogen heating unit 4, the flash heating unit 5, and the chamber 6 to perform heat treatment of the semiconductor wafer W.

[0047] The chamber 6 is formed by installing chamber windows made of quartz on the upper and lower parts of a cylindrical chamber side portion 61. The chamber side portion 61 has a generally cylindrical shape with upper and lower openings, and an upper chamber window 63 is installed at the upper opening to seal it, and a lower chamber window 64 is installed at the lower opening to seal it. The upper chamber window 63 constituting the top wall of the chamber 6 is a disk-shaped member formed of quartz, and functions as a quartz window that allows the flash emitted from the flash heating unit 5 to pass into the chamber 6. In addition, the lower chamber window 64 constituting the bottom wall of the chamber 6 is also a disk-shaped member formed of quartz, and functions as a quartz window that allows the light from the halogen heating unit 4 to pass into the chamber 6.

[0048] 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 the figure. That is, the reflection rings 68 and 69 are both installed on the chamber side portion 61 so as to be freely loaded and unloaded. 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 a heat treatment space 65.

[0049] The concave portion 62 is formed on the inner wall surface of the chamber 6 by attaching the reflection rings 68 and 69 to the chamber side portion 61. That is, the concave portion 62 is formed to be surrounded by the central portion of the inner wall surface of the chamber side portion 61 where the reflection rings 68 and 69 are not attached, the lower end surface of the reflection ring 68, and the upper end surface of the reflection ring 69. The concave portion 62 is formed in a circular ring shape in the horizontal direction on the inner wall surface of the chamber 6, and surrounds the holding portion 7 holding the semiconductor wafer W. The chamber side portion 61 and the reflection rings 68 and 69 are formed of a metal material (e.g., stainless steel) having excellent strength and heat resistance.

[0050] In addition, a transport opening (furnace port) 66 for carrying in and out the semiconductor wafer W relative to the chamber 6 is provided at the chamber side portion 61. The transport opening 66 can be opened and closed by the 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 wafer W can be carried into the heat treatment space 65 from the transport opening 66 through the recess 62, and the semiconductor wafer W can be carried out from the heat treatment space 65. In addition, if the gate valve 185 closes the transport opening 66, the heat treatment space 65 in the chamber 6 is set as a closed space.

[0051] Furthermore, a through hole 61a and a through hole 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 the semiconductor wafer W held on the crystal seat 74 described below 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 lower radiation thermometer 20. The through hole 61a and the through hole 61b are arranged obliquely with respect to the horizontal direction in such a manner that the axes of the through directions thereof intersect with the main surface of the semiconductor wafer W held on the crystal seat 74. At the end of the through hole 61a facing the heat treatment space 65, a transparent window 26 made of a calcium fluoride material is installed, which transmits infrared light in a wavelength range that can be measured by the upper radiation thermometer 25. Furthermore, a transparent window 21 made of a barium fluoride material that transmits infrared light in a wavelength range measurable by the lower radiation thermometer 20 is attached to the end of the through hole 61 b ​​on the side facing the heat treatment space 65 .

[0052] In addition, a gas supply hole 81 for supplying a processing gas to the heat treatment space 65 is provided at 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 at 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 midway along the path of the gas supply pipe 83. If the valve 84 is opened, the processing gas is transported from the processing gas supply source 85 to the buffer space 82. The processing gas flowing into the buffer space 82 flows in a diffused manner in the buffer space 82 where the fluid resistance is smaller than that of the gas supply hole 81, and is supplied from the gas supply hole 81 to the heat treatment space 65. As the processing gas, 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.

[0053] On the other hand, a gas exhaust hole 86 for exhausting the gas in the heat treatment space 65 is provided at the lower part of the inner wall of the chamber 6. The gas exhaust hole 86 is provided at a lower position than the recess 62, and may also be provided at 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 portion 190. In addition, a valve 89 is installed in the middle of the path of the gas exhaust pipe 88. If the valve 89 is opened, the gas in the heat treatment space 65 is discharged from the gas exhaust hole 86 to the gas exhaust pipe 88 via the buffer space 87. In addition, the gas supply hole 81 and the gas exhaust hole 86 may also be provided in a plurality along the circumferential direction of the chamber 6, or may be in a slit shape. In addition, the processing gas supply source 85 and the exhaust portion 190 may also be a mechanism provided in the heat treatment device 1, or may be a facility of a factory in which the heat treatment device 1 is provided.

[0054] A gas exhaust pipe 191 for exhausting the gas in the heat treatment space 65 is also connected to the front end of the transfer opening 66. The gas exhaust pipe 191 is connected to the exhaust unit 190 via a valve 192. The gas in the chamber 6 is exhausted through the transfer opening 66 by opening the valve 192.

[0055] Figure 2 : is a perspective view showing the overall appearance of the holding part 7. The holding part 7 is composed of a base ring 71, a connecting part 72 and a crystal seat 74. The base ring 71, the connecting part 72 and the crystal seat 74 are all formed of quartz. That is, the entire holding part 7 is formed of quartz.

[0056] The base ring 71 is a quartz member in an arc shape with a portion missing from the circular ring shape. The missing portion is provided to prevent interference between the transfer arm 11 of the transfer mechanism 10 described below and the base ring 71. The base ring 71 is supported on the wall surface of the chamber 6 by being placed on the bottom surface of the recess 62 (see Figure 1 ). On the upper surface of the base ring 71, a plurality of connecting parts 72 (four in this embodiment) are provided along the circumferential direction of the annular shape. The connecting part 72 is also a quartz member and is fixed to the base ring 71 by welding.

[0057] The crystal susceptor 74 is supported by four connecting portions 72 provided on the base ring 71 . Figure 3 74 is a top view of the crystal seat. Figure 4 74. The crystal base 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 formed 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 larger plane size than the semiconductor wafer W.

[0058] A guide ring 76 is provided on the peripheral portion of the upper surface of the holding plate 75. The guide ring 76 is a member in the shape of a circular ring having an inner diameter larger than the diameter of the semiconductor wafer W. For example, when the diameter of the semiconductor wafer W is φ300 mm, the inner diameter of the guide ring 76 is φ320 mm. The inner periphery of the guide ring 76 is provided as a tapered surface that widens upward from the holding plate 75. The guide ring 76 is formed of the same quartz 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 integral member.

[0059] The area on the upper surface of the holding plate 75 that is closer to the inner side than the guide ring 76 is set as a planar holding surface 75a for holding the semiconductor wafer W. A plurality of substrate support pins 77 are erected on the holding surface 75a of the holding plate 75. In this embodiment, a total of 12 substrate support pins 77 are erected at intervals of 30° along a circumference that is concentric with the outer circumference of the holding surface 75a (the inner circumference of the guide ring 76). The diameter of the circle formed by arranging the 12 substrate support pins 77 (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, it is φ270 mm to φ280 mm (φ270 mm in this embodiment). Each substrate support pin 77 is formed of quartz. A plurality of substrate support pins 77 can be set on the upper surface of the holding plate 75 by welding, or can be processed to be integrated with the holding plate 75.

[0060] Back to Figure 2 , the four connecting parts 72 erected on the base ring 71 and the peripheral part of the holding plate 75 of the crystal seat 74 are fixed by welding. That is, the crystal seat 74 and the base ring 71 are fixedly connected by the connecting parts 72. The holding part 7 is installed in the chamber 6 by supporting the base ring 71 of the holding part 7 on the wall surface of the chamber 6. When the holding part 7 is installed in the chamber 6, the holding plate 75 of the crystal seat 74 is in a horizontal posture (a posture in which the normal line is consistent with the vertical direction). That is, the holding surface 75a of the holding plate 75 becomes a horizontal plane.

[0061] The semiconductor wafer W carried into the chamber 6 is placed and held in a horizontal position on the crystal pedestal 74 of the holding portion 7 installed in the chamber 6. At this time, the semiconductor wafer W is supported by 12 substrate support pins 77 erected on the holding plate 75 and held on the crystal pedestal 74. More strictly speaking, the upper ends of the 12 substrate support pins 77 contact the lower surface of the semiconductor wafer W to support the semiconductor wafer W. Since the heights of the 12 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, the semiconductor wafer W can be supported in a horizontal position by the 12 substrate support pins 77.

[0062] In addition, the semiconductor wafer W is supported at a predetermined interval from the holding surface 75a of the holding plate 75 by the plurality of substrate supporting pins 77. The thickness of the guide ring 76 is greater than the height of the substrate supporting pins 77. Therefore, the guide ring 76 prevents the semiconductor wafer W supported by the plurality of substrate supporting pins 77 from being displaced in the horizontal direction.

[0063] In addition, if Figure 2 and Figure 3 As shown, an opening 78 is formed through the top and bottom of the holding plate 75 of the crystal base 74. The opening 78 is provided so that the lower radiation thermometer 20 receives the radiation light (infrared light) radiated from the lower surface of the semiconductor wafer W. That is, the lower radiation thermometer 20 receives the light radiated from the lower surface of the semiconductor wafer W through the opening 78 and the transparent window 21 installed in the through hole 61b of the chamber side 61 to measure the temperature of the semiconductor wafer W. Furthermore, four through holes 79 are formed in the holding plate 75 of the crystal base 74 so that the lift pins 12 of the transfer mechanism 10 described below can pass through to transfer the semiconductor wafer W.

[0064] Figure 5 1 is a top view of the transfer mechanism 10. Figure 6 1 is a side view of the transfer mechanism 10. The transfer mechanism 10 includes two transfer arms 11. The transfer arms 11 are formed in an arc shape along the substantially annular recess 62. Two lift pins 12 are provided vertically on each transfer arm 11. The transfer arms 11 and the lift pins 12 are formed of quartz. Each transfer arm 11 is configured to be rotatable by a horizontal moving mechanism 13. The horizontal moving mechanism 13 enables a pair of transfer arms 11 to be in a transfer operation position ( Figure 5 The solid line position), and the retreat position ( Figure 5 As the horizontal moving mechanism 13, each transfer arm 11 may be rotated separately by a separate motor, or a pair of transfer arms 11 may be rotated in conjunction with each other by a motor using a link mechanism.

[0065] 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 Figure 2 , 3), the upper end of the lift pin 12 protrudes from the upper surface of the crystal base 74. On the other hand, if the lifting mechanism 14 causes the pair of transfer arms 11 to descend in the transfer action position and pulls the lift pin 12 out of the through hole 79, and causes the horizontal moving mechanism 13 to move in a manner that causes the pair of transfer arms 11 to open, each transfer arm 11 moves to a retreat position. The retreat position of the pair of transfer arms 11 is directly above the base ring 71 of the holding 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 becomes 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 is configured to discharge the ambient gas around the drive portion of the transfer mechanism 10 to the outside of the chamber 6.

[0066] Back to Figure 1 The flash heating unit 5 disposed above the chamber 6 is provided with a light source including a plurality of (30 in the present embodiment) xenon flash lamps FL, and a reflector 52 disposed so as to cover the light source, on the inner side of a housing 51. In addition, a light radiation window 53 is installed at the bottom of the housing 51 of the flash heating unit 5. The light radiation window 53 constituting the bottom wall of the flash heating unit 5 is a plate-shaped quartz window formed of quartz. By disposing 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 the upper side of the chamber 6 through the light radiation window 53 and the upper chamber window 63.

[0067] The plurality of flash lamps FL are rod-shaped lamps each having a long cylindrical shape, and are arranged in a plane so that their respective length directions are parallel to each other along the main surface (i.e., along 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.

[0068] Figure 8 9 is a diagram showing a driving circuit of the flash lamp FL. As shown in the figure, a capacitor 93, a coil 94, a flash lamp FL, and an IGBT (insulated gate bipolar transistor) 96 are connected in series. Figure 8 As shown, the control unit 3 includes a pulse generator 31 and a waveform setting unit 32, and is connected to an input unit 33. As the input unit 33, various well-known input devices such as a keyboard, a mouse, and a touch panel can be used. The waveform setting unit 32 sets the waveform of the pulse signal based on the input content from the input unit 33, and the pulse generator 31 generates a pulse signal according to the waveform.

[0069] The flash lamp FL includes: a rod-shaped glass tube (discharge tube) 92, in which xenon gas is sealed and an anode and a cathode are arranged at both ends; and a trigger electrode 91, which is attached to the outer peripheral surface of the glass tube 92. A predetermined voltage is applied to the capacitor 93 by the power supply unit 95, and an electric charge corresponding to the applied voltage (charge voltage) is charged. In addition, a high voltage can be applied to the trigger electrode 91 from the trigger circuit 97. The timing of the trigger circuit 97 applying the voltage to the trigger electrode 91 is controlled by the control unit 3.

[0070] IGBT96 is a bipolar transistor in which a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is assembled in the gate part, and is a switching component suitable for handling high power. A pulse signal is applied to the gate of IGBT96 from the pulse generator 31 of the control unit 3. If a voltage (high voltage) greater than a specified value is applied to the gate of IGBT96, IGBT96 becomes an on state, and if a voltage (low voltage) less than the specified value is applied, IGBT96 becomes an off state. In this way, the drive circuit including the flash lamp FL is turned on and off by IGBT96. By turning on and off the IGBT96, the connection between the flash lamp FL and the corresponding capacitor 93 is intermittent, and the current flowing in the flash lamp FL is controlled by on and off.

[0071] Even if the IGBT 96 is turned on when the capacitor 93 is charged and a high voltage is applied to the electrodes at both ends of the glass tube 92, since the xenon gas is an electrical insulator, electricity does not flow in the glass tube 92 under normal conditions. However, when the trigger circuit 97 applies a high voltage to the trigger electrode 91 to break the insulation, the current flows in the glass tube 92 instantaneously due to the discharge between the electrodes at both ends, and the atoms or molecules of the xenon gas are excited at this time to emit light.

[0072] like Figure 8 The driving circuit shown in FIG. 1 is provided separately for each of the plurality of flash lamps FL provided in the flash heating unit 5. In this embodiment, 30 flash lamps FL are arranged in a plane, and 30 flash lamps FL are provided corresponding to them. Figure 8 Thus, the current flowing through each of the 30 flash lamps FL is individually controlled to be turned on and off through the corresponding IGBT 96 .

[0073] In addition, the reflector 52 is provided above the plurality of flash lamps FL so as to cover the entirety of the flash lamps FL. The basic function of the reflector 52 is to reflect the flash emitted from the plurality of flash lamps FL toward the side of the heat treatment space 65. The reflector 52 is formed of an aluminum alloy plate, and its surface (the surface facing the flash lamp FL) is roughened by sandblasting.

[0074] The halogen heating unit 4 provided below the chamber 6 has a plurality of (40 in this embodiment) halogen lamps HL built inside a housing 41. The halogen heating unit 4 is a light irradiation unit that heats the semiconductor wafer W by irradiating a heat treatment space 65 with light from below the chamber 6 through a lower chamber window 64 using a plurality of halogen lamps HL.

[0075] Figure 7 It is a top view showing the arrangement of a plurality of halogen lamps HL. 40 halogen lamps HL are arranged in two layers, upper and lower. Twenty halogen lamps HL are arranged in the upper layer close to the holding portion 7, and 20 halogen lamps HL are also arranged in the lower layer farther from the holding portion 7 than the upper layer. Each halogen lamp HL is a rod-shaped lamp with a long cylindrical shape. The 20 halogen lamps HL in both the upper and lower layers are arranged in parallel with each other along the main surface of the semiconductor wafer W held in the holding portion 7 (that is, in the horizontal direction) in their respective length directions. Thus, the plane formed by the arrangement of the halogen lamps HL is a horizontal plane in both the upper and lower layers.

[0076] 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 opposite to the peripheral portion than in the area opposite to the central portion of the semiconductor wafer W held by the holding portion 7. That is, in both the upper and lower layers, the halogen lamps HL are arranged at a shorter spacing in the peripheral portion than in the central portion of the lamp arrangement. Therefore, the peripheral portion of the semiconductor wafer W, which is prone to temperature drop when heated by light irradiation from the halogen heating portion 4, can be irradiated with a larger amount of light.

[0077] In addition, the lamp group including the upper halogen lamps HL and the lamp group including the lower halogen lamps HL are arranged in a lattice-like manner, that is, a total of 40 halogen lamps HL are arranged so that the length directions of the 20 halogen lamps HL arranged in the upper layer and the length directions of the 20 halogen lamps HL arranged in the lower layer are orthogonal to each other.

[0078] The halogen lamp HL is a filament-type light source that emits light by energizing a filament disposed inside a glass tube to turn the filament incandescent. Inside the glass tube, a gas obtained by introducing a trace amount of halogen elements (iodine, bromine, etc.) into an inert gas such as nitrogen or argon is sealed. By introducing the halogen element, the breakage of the filament can be suppressed and the temperature of the filament can be set to a high temperature. Therefore, compared with a conventional incandescent lamp, the halogen lamp HL has the characteristics of a longer life and continuous irradiation of stronger light. That is, the halogen lamp HL is a continuously lit lamp that emits light continuously for at least 1 second. In addition, since the halogen lamp HL is a rod-shaped lamp, it has a long life, and by arranging the halogen lamp HL in the horizontal direction, the radiation efficiency to the semiconductor wafer W above is excellent.

[0079] 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 side.

[0080] The control unit 3 controls the above-mentioned various action mechanisms provided in the heat treatment device 1. The hardware structure of the control unit 3 is the same as that of a general computer. That is, the control unit 3 includes a circuit CPU (Central Processing Unit) for performing various calculations, a read-only memory ROM (Read Only Memory) for storing basic programs, a readable and writable memory RAM (Random Access Memory) for storing various information, and a magnetic disk for pre-storing control software or data. The CPU of the control unit 3 performs the processing in the heat treatment device 1 by executing a prescribed processing program. In addition, the control unit 3 includes a pulse generator 31 and a waveform setting unit 32 ( Figure 8 ), the waveform setting unit 32 sets the waveform of the pulse signal based on the input content from the input unit 33, and the pulse generator 31 outputs a pulse signal to the gate of the IGBT96 according to the waveform.

[0081] In addition, if Figure 1 As shown, the heat treatment apparatus 1 includes an upper radiation thermometer 25 and a lower radiation thermometer 20. The upper radiation thermometer 25 is a high-speed radiation thermometer for measuring a rapid temperature change of the upper surface of the semiconductor wafer W when the flash lamp FL emits a flash.

[0082] Fig. 9 1 is a block diagram showing the structure of the high-speed radiation thermometer unit 101 including the main part of the upper radiation thermometer 25. The infrared sensor 29 of the upper radiation thermometer 25 is mounted on the outer wall surface of the chamber side portion 61 in such a manner that its optical axis is aligned with the axis of the through-hole 61a in the through-hole direction. The infrared sensor 29 receives infrared light radiated from the upper surface of the semiconductor wafer W held on the crystal seat 74 via the transparent window 26 of calcium fluoride. The infrared sensor 29 has an optical component of InSb (indium antimonide) whose measurement wavelength range is 5μm to 6.5μm. The transparent window 26 of calcium fluoride selectively transmits infrared light in the measurement wavelength range of the infrared sensor 29. The resistance of the InSb optical component changes according to the intensity of the received infrared light. The infrared sensor 29 having the InSb optical component is capable of high-speed measurement with an extremely short response time and a significantly short sampling interval (the shortest is about 20 microseconds). The infrared sensor 29 is electrically connected to the high-speed radiation thermometer unit 101 , and transmits a signal generated in response to receiving light to the high-speed radiation thermometer unit 101 .

[0083] The high-speed radiation thermometer unit 101 includes a signal conversion circuit 102, an amplifier circuit 103, an A / D (Analog / Digital) converter 104, and a temperature conversion unit 105. The signal conversion circuit 102 is a circuit that converts the resistance change generated in the InSb optical component of the infrared sensor 29 in the order of current change and voltage change, and finally converts it into an easy-to-process voltage signal and outputs it. The signal conversion circuit 102 is configured using an operational amplifier, for example. The amplifier circuit 103 amplifies the voltage signal output from the signal conversion circuit 102 and outputs it to the A / D converter 104. The A / D converter 104 converts the voltage signal amplified by the amplifier circuit 103 into a digital signal.

[0084] The temperature conversion unit 105 performs a predetermined calculation process on the signal output from the A / D converter 104, that is, the signal indicating the intensity of the infrared light received by the infrared sensor 29, and converts it into a temperature. The temperature obtained by the temperature conversion unit 105 is the temperature of the upper surface of the semiconductor wafer W. In addition, the infrared sensor 29, the signal conversion circuit 102, the amplifier circuit 103, the A / D converter 104, and the temperature conversion unit 105 constitute the upper radiation thermometer 25. The lower radiation thermometer 20 also has a configuration substantially the same as that of the upper radiation thermometer 25, but does not need to be capable of high-speed measurement.

[0085] like Fig. 9 As shown, the high-speed radiation thermometer unit 101 is electrically connected to the controller 3 of the entire heat treatment device 1. Fig. 9 In addition to the above (not shown in the figure), the control unit 3 includes a prediction unit 35. The prediction unit 35 is a functional processing unit implemented by the CPU of the control unit 3 executing a predetermined processing program. The processing content of the prediction unit 35 will be further described below.

[0086] In addition, the control unit 3 is connected to a display unit 34 and an input unit 33. The control unit 3 displays various information on the display unit 34. The operator of the heat treatment device 1 can input various instructions or parameters from the input unit 33 while confirming the information displayed on the display unit 34. As the display unit 34 and the input unit 33, for example, a liquid crystal touch panel provided on the outer wall of the heat treatment device 1 can also be used. Furthermore, the control unit 3 is connected to an IGBT 96, and the IGBT 96 is turned on and off by applying a pulse signal from the control unit 3 to the gate of the IGBT 96. In addition, Fig. 9 The storage unit 36 ​​shown is a storage medium such as a disk or a memory of the control unit 3 .

[0087] In addition to the above-mentioned configuration, the heat treatment apparatus 1 also has various cooling structures to prevent the halogen heating unit 4, the flash heating unit 5, and the chamber 6 from excessive temperature rise due to the heat energy generated by the halogen lamp HL and the flash lamp FL during the heat treatment of the semiconductor wafer W. For example, a water cooling pipe (not shown) is provided on the wall of the chamber 6. In addition, the halogen heating unit 4 and the flash heating unit 5 are provided with an air cooling structure for exhausting heat by forming an air flow inside. 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 unit 5 and the upper chamber window 63.

[0088] Next, the processing operation of the heat treatment apparatus 1 will be described. Fig.10 1 is a flowchart showing the processing sequence of the heat treatment apparatus 1 according to the first embodiment. The semiconductor wafer W to be processed is a semiconductor substrate to which impurities (ions) are added by ion implantation. The activation of the impurities is performed by flash irradiation heating (annealing) of the heat treatment apparatus 1. The processing sequence of the heat treatment apparatus 1 described below is performed by the control unit 3 controlling each action mechanism of the heat treatment apparatus 1.

[0089] First, the valve 84 for supplying gas is opened, and the valves 89 and 192 for exhausting gas are opened to start supplying and exhausting gas in the chamber 6. When the valve 84 is opened, nitrogen gas is supplied to the heat treatment space 65 from the gas supply hole 81. In addition, when the valve 89 is opened, the gas in the chamber 6 is exhausted from the gas exhaust hole 86. Thus, the nitrogen gas supplied from the upper part of the heat treatment space 65 in the chamber 6 flows downward, and is exhausted from the lower part of the heat treatment space 65.

[0090] In addition, the gas in the chamber 6 is also exhausted from the transfer opening 66 by opening the valve 192. Furthermore, the atmosphere around the driving part of the transfer mechanism 10 is also exhausted by the exhaust mechanism (not shown). In addition, 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 thereof is appropriately changed according to the treatment step.

[0091] Next, the gate valve 185 is opened to open the transfer opening 66, and the semiconductor wafer W to be processed is transferred into the heat treatment space 65 in the chamber 6 through the transfer opening 66 by a transfer robot outside the apparatus (step S11). At this time, there is a concern that the ambient air outside the apparatus may be entrained with the transfer of the semiconductor wafer W, but since nitrogen gas is continuously supplied to the chamber 6, nitrogen gas flows out from the transfer opening 66, and the entrainment of such ambient air can be minimized.

[0092] The semiconductor wafer W carried in by the transfer robot enters the position just above the holding portion 7 and stops. Then, the pair of transfer arms 11 of the transfer mechanism 10 horizontally move from the retracted position to the transfer operation position and rise, whereby the lift pins 12 protrude from the upper surface of the holding plate 75 of the crystal base 74 through the through holes 79 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.

[0093] After the semiconductor wafer W is placed on the lift 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 semiconductor wafer W is transferred from the transport mechanism 10 to the crystal seat 74 of the holding part 7 by the pair of transfer arms 11 descending, and is held from below in a horizontal posture. The semiconductor wafer W is supported by a plurality of substrate support pins 77 erected on the holding plate 75 and held on the crystal seat 74. In addition, the semiconductor wafer W is held on the holding part 7 with the front side where the pattern formation is completed and the impurities are injected as the upper surface. A predetermined gap is formed between the back side (the main surface on the opposite side to the front side) 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 descending to the bottom of the crystal seat 74 retreat to the retreat position, that is, the inner side of the recess 62, by the horizontal moving mechanism 13.

[0094] After the semiconductor wafer W is held horizontally from below by the crystal seat 74 of the holding part 7 formed of quartz, the 40 halogen lamps HL of the halogen heating part 4 are simultaneously lit to start preheating (auxiliary heating) (step S12). The halogen light emitted from the halogen lamp HL passes through the lower chamber window 64 and the crystal seat 74 formed of quartz and irradiates the lower surface of the semiconductor wafer W. The semiconductor wafer W is preheated by being irradiated with light from the halogen lamp HL, so that the temperature rises. In addition, since the transfer arm 11 of the transfer mechanism 10 retreats to the inner side of the recess 62, it will not hinder the heating of the halogen lamp HL.

[0095] When preheating is performed using the halogen lamp HL, the temperature of the semiconductor wafer W is measured by the lower radiation thermometer 20. That is, the infrared light radiated from the lower surface of the semiconductor wafer W held on the crystal base 74 through the opening 78 is received by the lower radiation thermometer 20 through the transparent window 21 to measure the temperature of the wafer during heating. 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 lamp HL while monitoring whether the temperature of the semiconductor wafer W heated by the light irradiation from the halogen lamp HL has reached the prescribed preheating temperature T1. That is, the control unit 3 performs feedback control on the output of the halogen lamp HL based on the measured value of the lower radiation thermometer 20 so that the temperature of the semiconductor wafer W reaches the preheating temperature T1. In this way, the lower radiation thermometer 20 is a radiation thermometer used for temperature control of the semiconductor wafer W during preheating. The preheating temperature T1 is set to about 200° C. to 800° C., preferably about 350° C. to 600° C. (600° C. in the present embodiment), so that there is no concern that impurities added to the semiconductor wafer W will diffuse due to heat.

[0096] 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, at the time point 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 lamp HL to maintain the temperature of the semiconductor wafer W approximately at the preheating temperature T1.

[0097] By performing such preheating with the halogen lamp HL, the temperature of the entire semiconductor wafer W is uniformly raised to the preheating temperature T1. In the stage of preheating with the halogen lamp HL, there is a tendency that the temperature of the peripheral portion of the semiconductor wafer W, which is more likely to generate heat dissipation, is lower than that of the central portion, but the arrangement density of the halogen lamp HL of the halogen heating unit 4 is higher in the area facing the peripheral portion than in the area facing the central portion of the semiconductor wafer W. Therefore, the amount of light irradiated to the peripheral portion of the semiconductor wafer W, which is more likely to generate heat dissipation, becomes larger, and the in-plane temperature distribution of the semiconductor wafer W in the preheating stage can be made uniform.

[0098] In addition, from the time of preheating the semiconductor wafer W, the surface temperature of the semiconductor wafer W is measured by the upper radiation thermometer 25. Infrared light of an intensity corresponding to the temperature is radiated from the surface of the heated semiconductor wafer W. The infrared light radiated from the surface of the semiconductor wafer W is received by the infrared sensor 29 of the upper radiation thermometer 25 through the transparent window 26.

[0099] In the InSb optical component of the infrared sensor 29, a resistance change corresponding to the intensity of the received infrared light occurs. The resistance change generated in the InSb optical component of the infrared sensor 29 is converted into a voltage signal by the signal conversion circuit 102. The voltage signal output from the signal conversion circuit 102 is amplified by the amplifier circuit 103 and converted into a digital signal suitable for computer processing by the A / D converter 104. Then, the temperature conversion unit 105 performs a predetermined operation process on the signal output from the A / D converter 104 and converts it into temperature data. That is, the upper radiation thermometer 25 receives the infrared light radiated from the surface of the heated semiconductor wafer W, and measures the surface temperature of the semiconductor wafer W according to the intensity of the infrared light. The surface temperature of the semiconductor wafer W measured by the upper radiation thermometer 25 is transmitted to the control unit 3.

[0100] Fig.11 2 is a graph showing the change in the surface temperature of the semiconductor wafer W measured by the upper radiation thermometer 25. At time t1 after the temperature of the semiconductor wafer W reaches the preheating temperature T1 and a predetermined time has passed, the flash lamp FL of the flash heating unit 5 starts flash irradiation of the surface of the semiconductor wafer W held on the crystal base 74 (step S13). At this time, part of the flash irradiated from the flash lamp FL is directly directed into the chamber 6, and the other part is temporarily reflected by the reflector 52 and then directed into the chamber 6, and the semiconductor wafer W is flash heated by these flash irradiations.

[0101] When flash lamp FL performs flash irradiation, electric charge is stored in capacitor 93 by power supply unit 95. Then, with electric charge stored in capacitor 93, pulse generator 31 of control unit 3 outputs a pulse signal to IGBT 96 to drive IGBT 96 on and off.

[0102] The waveform of the pulse signal can be specified by inputting a rule that is sequentially set with the pulse width time (on time) and the pulse interval time (off time) as parameters from the input unit 33. When the operator inputs such a rule from the input unit 33 to the control unit 3, the waveform setting unit 32 of the control unit 3 sets a pulse waveform that repeatedly turns on and off. Then, the pulse generator 31 outputs a pulse signal according to the pulse waveform set by the waveform setting unit 32. Fig.12 This is a diagram showing an example of a waveform of a pulse signal. Fig.12 In the example shown, a plurality of pulses are repeatedly set, and the pulse width time (on time) is longer than the pulse interval time (off time). Fig.12The pulse signal of the waveform controls the on-off driving of the IGBT 96. Specifically, when the pulse signal input to the gate of the IGBT 96 is on, the IGBT 96 is in the on state, and when the pulse signal is off, the IGBT 96 is in the off state.

[0103] In synchronization with the timing when the pulse signal output from the pulse generator 31 turns on, the control unit 3 controls the trigger circuit 97 to apply a high voltage (trigger voltage) to the trigger electrode 91. A pulse signal is input to the gate of the IGBT 96 in a state where the charge is stored in the capacitor 93, and a high voltage is applied to the trigger electrode 91 in synchronization with the timing when the pulse signal turns on, so that when the pulse signal turns on, current flows between the electrodes at both ends of the glass tube 92, and light is emitted by the excitation of atoms or molecules of the xenon gas at this time.

[0104] In this way, the 30 flash lamps FL of the flash heating unit 5 emit light, and the surface of the semiconductor wafer W held in the holding unit 7 is irradiated with flash light. Here, when the flash lamp FL is made to emit light without using the IGBT 96, the charge stored in the capacitor 93 is consumed by one light emission, and the output waveform from the flash lamp FL becomes a simple single pulse with a width of about 0.1 milliseconds to 10 milliseconds. In contrast, in this embodiment, the IGBT 96 as a switching element is connected to the circuit and a pulse signal is output to its gate, so that the IGBT 96 continuously supplies charge from the capacitor 93 to the flash lamp FL, thereby controlling the on and off of the current flowing in the flash lamp FL. As a result, the light emission of the flash lamp FL is controlled by chopping in a sense, the charge stored in the capacitor 93 is divided and consumed, and the flash lamp FL repeatedly turns on and off in a very short period of time. In addition, before the current value flowing in the circuit completely becomes "0", the next pulse is applied to the gate of IGBT96 and the current value increases again. Therefore, the light output is not completely "0" during the period when the flash lamp FL repeatedly turns on and off.

[0105] By controlling the on / off of the current flowing through the flash lamp FL through the IGBT 96, the light emission pattern (time waveform of light emission output) of the flash lamp FL can be freely specified, and the light emission time and light emission intensity can be freely adjusted. The on / off driving pattern of the IGBT 96 is specified by the time of the pulse width and the time of the pulse interval input from the input unit 33. That is, by assembling the IGBT 96 into the driving circuit of the flash lamp FL, the light emission pattern of the flash lamp FL can be freely specified by only appropriately setting the time of the pulse width and the time of the pulse interval input from the input unit 33.

[0106] Specifically, for example, if the ratio of the time of the pulse width input from the input unit 33 to the time of the pulse interval is increased, the current flowing through the flash lamp FL increases and the luminous intensity becomes stronger. On the contrary, if the ratio of the time of the pulse width input from the input unit 33 to the time of the pulse interval is reduced, the current flowing through the flash lamp FL decreases and the luminous intensity becomes weaker. In addition, if the ratio of the time of the pulse interval input from the input unit 33 to the time of the pulse width is appropriately adjusted, the luminous intensity of the flash lamp FL can be maintained constant. Furthermore, by extending the total time of the combination of the time of the pulse width input from the input unit 33 and the time of the pulse interval, the current continues to flow through the flash lamp FL for a long time, thereby lengthening the luminous time of the flash lamp FL. The luminous time of the flash lamp FL is appropriately set between 0.1 milliseconds and 100 milliseconds.

[0107] In this way, the surface of the semiconductor wafer W is irradiated with flash light from the flash lamp FL, and the temperature of the surface is increased. The surface temperature of the semiconductor wafer W which is heated by the flash light irradiation is also measured by the upper radiation thermometer 25. Although the light emission time of the flash lamp FL is a short time of 0.1 milliseconds to 100 milliseconds, the sampling interval of the upper radiation thermometer 25 equipped with the InSb optical component is an extremely short time of about 20 microseconds (that is, 50 points can be measured within 1 millisecond). Therefore, the change in the surface temperature of the semiconductor wafer W which is rapidly heated by the flash light irradiation can be measured by the upper radiation thermometer 25 ( Fig.11 ).

[0108] In the first embodiment, the control unit 3 monitors whether the surface temperature of the semiconductor wafer W measured by the upper radiation thermometer 25 has reached the target temperature T2 (step S14). The target temperature T2 is a temperature required to achieve the purpose of heating the semiconductor wafer W, and in this embodiment, it is 1000° C. or more to activate the impurities injected into the semiconductor wafer W. The target temperature T2 is preset and stored in the storage unit 36.

[0109] When the surface temperature of the semiconductor wafer W measured by the upper radiation thermometer 25 reaches the target temperature T2 at time t2, the process proceeds from step S14 to step S15, and the current supply to the flash lamp FL is stopped under the control of the control unit 3. Specifically, at time t2 when the surface temperature of the semiconductor wafer W reaches the target temperature T2, the control unit 3 turns off the pulse signal applied to the gate of the IGBT 96.

[0110] Fig.13 is a diagram showing the change of the current flowing through the flash lamp FL. At time t1, the gate of the IGBT 96 is applied with the following Fig.12 The pulse signal of the waveform shown in the figure increases the current flowing through the flash lamp FL and the flash lamp FL starts to emit light. Fig.12As shown in FIG. 1 , the pulse signal applied to the gate of the IGBT 96 is repeatedly turned on and off, so the current flowing through the flash lamp FL also repeatedly increases and decreases accordingly. That is, when the pulse signal applied to the gate of the IGBT 96 is turned on, the current flowing through the flash lamp FL increases, and when the pulse signal is turned off, the current flowing through the flash lamp FL decreases. Fig.12 In the example shown, the on time of the pulse signal is longer than the off time, so Fig.13 As shown, the current flowing through the flash lamp FL increases and decreases repeatedly but increases as a whole. As the current flowing through the flash lamp FL increases, the light output of the flash lamp FL also increases.

[0111] Next, at time t2 when the surface temperature of the semiconductor wafer W reaches the target temperature T2, the control unit 3 turns off the pulse signal applied to the gate of the IGBT 96. At this time, the control unit 3 turns off the pulse signal applied to the gate of the IGBT 96 regardless of the waveform of the pulse signal set by the waveform setting unit 32. That is, even if the pulse signal set by the waveform setting unit 32 is on at time t2, the control unit 3 forcibly turns off the pulse signal at time t2. As a result, the IGBT 96 is turned off after time t2, and the current supply to the flash lamp FL is stopped.

[0112] If the current supply to the flash lamp FL is stopped at time t2, the light emission of the flash lamp FL also stops, and the surface temperature of the semiconductor wafer W drops rapidly from the target temperature T2. By raising the surface temperature of the semiconductor wafer W to the target temperature T2 in a very short time and then cooling it down, the impurities injected into the semiconductor wafer W can be activated while suppressing the diffusion of the impurities due to heat.

[0113] The halogen lamp HL goes out after a predetermined time has passed since the current supply to the flash lamp FL is stopped. As a result, the semiconductor wafer W is rapidly cooled from the preheating temperature T1. The temperature of the semiconductor wafer W being cooled is measured by the lower radiation thermometer 20, and the measurement result is transmitted to the control unit 3. The control unit 3 monitors whether the temperature of the semiconductor wafer W has been cooled to a predetermined temperature based on the measurement result of the lower radiation thermometer 20. Moreover, after the temperature of the semiconductor wafer W is cooled to below the predetermined temperature, the pair of transfer arms 11 of the transfer mechanism 10 are horizontally moved from the retreat position to the transfer action position again and rise, whereby the lift pins 12 protrude from the upper surface of the crystal seat 74 and receive the semiconductor wafer W after the heat treatment from the crystal seat 74. Then, the closed transport opening 66 is opened by the gate valve 185, and the semiconductor wafer W placed on the lift pins 12 is moved out by the transport robot outside the device, and the heating treatment of the semiconductor wafer W in the heat treatment device 1 is completed (step S16).

[0114] In the first embodiment, the surface temperature of the semiconductor wafer W heated by the flash irradiation from the flash lamp FL is measured by the upper radiation thermometer 25. Then, when the surface temperature of the semiconductor wafer W measured by the upper radiation thermometer 25 reaches the target temperature T2, the current supply to the flash lamp FL is stopped to reduce the surface temperature of the semiconductor wafer W. Since the current supply to the flash lamp FL is stopped when the measured surface temperature of the semiconductor wafer W reaches the target temperature T2, the surface temperature of the semiconductor wafer W can be accurately raised to the target temperature T2 regardless of the surface state or reflectivity of the semiconductor wafer W. As a result, the peak temperature is constant even when a plurality of semiconductor wafers W are processed, and the variation in device performance can be suppressed.

[0115] <Second embodiment>

[0116] Next, the second embodiment of the present invention will be described. The configuration of the heat treatment apparatus of the second embodiment is completely the same as that of the first embodiment. In addition, the processing sequence of the semiconductor wafer W of the second embodiment is also substantially the same as that of the first embodiment. In the first embodiment, the current supply to the flash lamp FL is stopped when the measured value of the surface temperature of the semiconductor wafer W reaches the target temperature T2, but in the second embodiment, the predetermined time when the surface temperature of the semiconductor wafer W reaches the target temperature T2 is predicted, and the current supply to the flash lamp FL is stopped at the predetermined time.

[0117] Fig.14 It is a flowchart showing the processing procedure of the heat treatment apparatus 1 according to the second embodiment. Fig.14 Steps S21 to S23 are Fig.10 The steps S11 to S13 are the same as those of the above. That is, the semiconductor wafer W to be processed is carried into the chamber 6 and held on the crystal base 74 (step S21). Then, the halogen lamp HL is turned on to preheat the semiconductor wafer W (step S22). In addition, after the preheating starts, the surface temperature of the semiconductor wafer W is measured by the upper radiation thermometer 25. Fig.15 2 is a diagram showing the change in the surface temperature of the semiconductor wafer W in the second embodiment. As in the first embodiment, at time t1 after the temperature of the semiconductor wafer W reaches the preheating temperature T1 after the predetermined time has passed after the preheating, the flash lamp FL starts flashing the surface of the semiconductor wafer W (step S23). Fig.12 A pulse signal of the waveform shown is applied to the gate of the IGBT 96 to cause the flash lamp FL to emit light, irradiating the surface of the semiconductor wafer W with the flash light to increase the temperature of the front surface.

[0118] In the second embodiment, at time t3 after the flash irradiation starts and before the surface temperature of the semiconductor wafer W reaches the target temperature T2, the prediction unit 35 ( Fig. 9 ) predicts the change in the surface temperature of the semiconductor wafer W. More specifically, the prediction unit 35 predicts the scheduled time t4 at which the surface temperature of the semiconductor wafer W reaches the target temperature T2 based on the temperature measurement results of the upper radiation thermometer 25 from time t1 to time t3 (step S24).

[0119] like Fig. 9 As shown, the storage unit 36 ​​of the control unit 3 stores a plurality of temperature rise patterns PT obtained by measuring the surface temperature of the semiconductor wafer W during flash irradiation in the past (for example, temperature rise patterns for 1000 semiconductor wafers W). That is, the storage unit 36 ​​obtains the temperature distribution indicating the surface temperature change during flash irradiation for the plurality of semiconductor wafers W and stores it as the temperature rise pattern PT. The prediction unit 35 compares the temperature measurement result of the upper radiation thermometer 25 from time t1 to time t3 with the past performance, i.e., the plurality of temperature rise patterns PT, and predicts the expected time t4 when the surface temperature of the semiconductor wafer W reaches the target temperature T2. The prediction unit 35 extracts a temperature rise pattern PT similar to the temperature measurement result of the upper radiation thermometer 25 from time t1 to time t3 from the plurality of temperature rise patterns PT by a pattern matching method, for example, and predicts the expected time t4 when the surface temperature of the semiconductor wafer W reaches the target temperature T2 based on the extracted temperature rise pattern PT.

[0120] The control unit 3 monitors whether the time has reached the scheduled time t4 by means of a timer (not shown) (step S25). Then, if the time reaches the scheduled time t4, the process proceeds from step S25 to step S26, and the current supply to the flash lamp FL is stopped by the control of the control unit 3. Specifically, similarly to the first embodiment, the control unit 3 turns off the pulse signal applied to the gate of the IGBT 96 at the scheduled time t4. At this time, regardless of the waveform of the pulse signal set by the waveform setting unit 32, the control unit 3 turns off the pulse signal applied to the gate of the IGBT 96. As a result, after the scheduled time t4, the IGBT 96 is turned off, and the current supply to the flash lamp FL is stopped.

[0121] When the current supply to the flash lamp FL is stopped at the predetermined time t4, the light emission of the flash lamp FL also stops, and the surface temperature of the semiconductor wafer W drops rapidly from the target temperature T2. By raising the surface temperature of the semiconductor wafer W to the target temperature T2 in a very short time and then dropping the temperature, the impurities injected into the semiconductor wafer W can be activated while suppressing the diffusion of the impurities due to heat.

[0122] After a predetermined time has passed since the current supply to the flash lamp FL is stopped, the halogen lamp HL is turned off. As a result, the temperature of the semiconductor wafer W is rapidly reduced from the preheating temperature T1. Then, similarly to the first embodiment, after the temperature of the semiconductor wafer W is reduced to a predetermined temperature or below, the semiconductor wafer W is unloaded from the chamber 6 and the heating treatment of the semiconductor wafer W in the heat treatment apparatus 1 is completed (step S27).

[0123] In the second embodiment, the surface temperature of the semiconductor wafer W heated by the flash irradiation from the flash lamp FL is measured by the upper radiation thermometer 25, and the expected arrival time t4 when the surface temperature of the semiconductor wafer W reaches the target temperature T2 is predicted from the temperature measurement result. Then, the current supply to the flash lamp FL is stopped at the expected arrival time t4 to reduce the surface temperature of the semiconductor wafer W. If the surface temperature of the semiconductor wafer W reaches the target temperature T2, the current supply to the flash lamp FL is stopped at the predicted expected arrival time t4, so that the surface temperature of the semiconductor wafer W can be accurately raised to the target temperature T2 regardless of the surface state or reflectivity of the semiconductor wafer W. As a result, the peak temperature is constant even when a plurality of semiconductor wafers W are processed, so that the variation of device performance can be suppressed.

[0124] <Example of Change>

[0125] The embodiments of the present invention have been described above, but the present invention can be modified in various ways other than the above within the scope of the gist thereof. For example, in the second embodiment, the current supply to the flash lamp FL is stopped at the predetermined time t4, but the present invention is not limited to this, and the current supply to the flash lamp FL may be stopped with a predetermined range before or after the predetermined time t4. That is, the current supply to the flash lamp FL may be stopped within a predetermined period including the predetermined time t4 to reduce the surface temperature of the semiconductor wafer W. The deviation range of the time of stopping the current supply from the predetermined time t4 may be set in advance and stored in the storage unit 36 ​​or the like.

[0126] In addition, in the above embodiment, the output is as follows Fig.12 Although the pulse signal of the waveform of a plurality of pulses is repeatedly set as shown, for example, a pulse signal of the waveform of a single longer pulse may be input to the gate of the IGBT 96. In this case, when the measured surface temperature of the semiconductor wafer W reaches the target temperature T2 or reaches the predetermined time t4, the control unit 3 turns off the pulse signal applied to the gate of the IGBT 96, thereby stopping the current supply to the flash lamp FL, and obtaining the same effect as the above-mentioned embodiment.

[0127] In the above embodiment, the current supply to the flash lamp FL is stopped by turning off the IGBT 96, but the present invention is not limited thereto, and the current supply may be stopped by blocking the charge supply from the container 93 to the flash lamp FL by a switch element different from the IGBT 96. Alternatively, a mechanical shutter may be provided in the flash heating unit 5, and the flash radiated from the flash lamp FL may be shielded by closing the mechanical shutter at a predetermined timing.

[0128] In addition, in the above embodiment, the flash heating unit 5 is provided with 30 flash lamps FL, but the present invention is not limited thereto, and the number of flash lamps FL can be set to any number. In addition, the flash lamp FL is not limited to a xenon flash lamp, and can also be a krypton flash lamp. In addition, the number of halogen lamps HL provided in the halogen heating unit 4 is not limited to 40, and can be set to any number.

[0129] In addition, in the above-mentioned embodiment, a filament-type halogen lamp HL is used as a continuous lighting lamp that emits light continuously for more than 1 second to preheat the semiconductor chip W, but this is not limited to this. A discharge-type arc lamp (such as a xenon arc lamp) may be used as a continuous lighting lamp to preheat the semiconductor chip W instead of the halogen lamp HL.

[0130] In addition, according to the heat treatment apparatus 1, the substrate to be processed is not limited to a semiconductor wafer, but may be a glass substrate for a flat panel display such as a liquid crystal display device or a substrate for a solar cell. In addition, in the heat treatment apparatus 1, heat treatment of a high dielectric constant gate insulating film (High-k film), bonding of metal and silicon, or crystallization of polysilicon may also be performed.

[0131] [Description of Reference Numerals]

[0132] 1: Heat treatment device

[0133] 3: Control Department

[0134] 4: Halogen heating unit

[0135] 5: Flash heating unit

[0136] 6: Chamber

[0137] 7: Maintaining part

[0138] 10: Transfer mechanism

[0139] 20: Lower radiation thermometer

[0140] 25: Upper radiation thermometer

[0141] 29: Infrared sensor

[0142] 33: Input

[0143] 34: Display unit

[0144] 35: Forecasting Department

[0145] 36: Storage

[0146] 63: Upper chamber window

[0147] 64: Lower chamber window

[0148] 65: Heat treatment space

[0149] 74: Crystal seat

[0150] 96: IGBT

[0151] 101: High-speed radiation thermometer unit

[0152] 105: Temperature conversion unit

[0153] FL: Flash light

[0154] HL: Halogen lamp

[0155] W: semiconductor wafer

Claims

1. A heat treatment method, characterized in that: A method for heating a substrate by irradiating a substrate with a flash of light, comprising: a flash irradiation step of irradiating a flash from a flash lamp to a surface of the substrate to increase the temperature of the surface; a temperature measuring step of measuring the temperature of the surface of the heated substrate by a radiation thermometer; and a light emission stopping step of stopping the current supply to the flash lamp to cool the surface temperature when the surface temperature measured by the radiation thermometer reaches a target temperature, In the light emission stopping step, a pulse signal applied to a gate of an IGBT connected to the flash lamp is turned off to stop supplying current to the flash lamp.

2. A heat treatment method, characterized in that: The substrate is heated by irradiating a flash of light onto the substrate, comprising: a flash irradiation step of irradiating a flash from a flash lamp to a surface of the substrate to increase the temperature of the surface; a temperature measuring step of measuring the temperature of the surface of the heated substrate by a radiation thermometer; A prediction step of predicting a predetermined time when the temperature of the surface reaches a target temperature based on the temperature measurement result of the radiation thermometer; and a light emission stopping step of stopping the current supply to the flash lamp to cool the surface within a predetermined period including the predetermined time predicted in the prediction step, In the light emission stopping step, a pulse signal applied to a gate of an IGBT connected to the flash lamp is turned off to stop supplying current to the flash lamp.

3. The heat treatment method according to claim 2, wherein: In the light emission stopping step, supply of current to the flash lamp is stopped when the predetermined timing is reached.

4. The heat treatment method according to claim 2, wherein: In the prediction step, the estimated arrival time is predicted based on a plurality of temperature rise patterns acquired when the flash irradiation is performed.

5. A heat treatment device, characterized in that: The substrate is heated by irradiating a flash of light onto the substrate, comprising: a chamber that receives a substrate; a flash lamp that irradiates a surface of the substrate contained in the chamber with a flash to increase the temperature of the surface; a radiation thermometer for measuring the temperature of the surface of the heated substrate; and a switch section that stops supplying current to the flash lamp to lower the temperature of the surface when the temperature of the surface measured by the radiation thermometer reaches a target temperature, The switch unit includes an IGBT connected to the flash lamp, and stops supplying current to the flash lamp by turning off a pulse signal applied to a gate of the IGBT.

6. A heat treatment device, characterized in that: The substrate is heated by irradiating a flash of light onto the substrate, comprising: a chamber that receives a substrate; a flash lamp that irradiates a surface of the substrate contained in the chamber with a flash to increase the temperature of the surface; a radiation thermometer for measuring the temperature of the surface of the heated substrate; a prediction unit that predicts a time when the temperature of the surface reaches a target temperature based on the temperature measurement result of the radiation thermometer; and a switch section that stops supplying current to the flash lamp to reduce the temperature of the surface within a predetermined period including the predetermined arrival time predicted by the prediction section, The switch unit includes an IGBT connected to the flash lamp, and stops supplying current to the flash lamp by turning off a pulse signal applied to a gate of the IGBT.

7. The heat treatment device according to claim 6, wherein: The switch section stops supplying current to the flash lamp when the predetermined timing is reached.

8. The heat treatment device according to claim 6, wherein: The device further comprises a storage unit for storing a plurality of temperature rise patterns obtained when the flash irradiation is performed. The prediction unit predicts the expected arrival time based on the plurality of temperature rise patterns.

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