Heat treatment device

Abstract

The invention provides a heat treatment apparatus capable of efficiently heating a substrate to a high temperature. This heat treatment apparatus is provided with a flash heating unit provided with a plurality of flash lamps on the upper side of a chamber in which a semiconductor wafer is housed, and with an auxiliary heating unit provided with a plurality of laser diodes and a plurality of VCSELs on the lower side. When a semiconductor wafer is preheated, light emitted from a laser diode is irradiated to the entire surface of the semiconductor wafer with uniform illuminance distribution through an optical element, and light with high directivity is irradiated from a VCSEL to the peripheral edge of the semiconductor wafer. Since the laser diode irradiates the semiconductor wafer with light having a wavelength shorter than 1 [mu] m and a relatively high intensity, the semiconductor wafer can be efficiently heated to a high temperature. In addition, the in-plane temperature distribution of the semiconductor wafer can be made uniform by irradiation with light from the VCSEL.

Description

Technical Field

[0001] The present invention relates to a heat treatment device for heating a substrate by irradiating light onto the substrate. The substrate to be treated includes, for example, a semiconductor wafer, a substrate for a liquid crystal display device, a substrate for a flat panel display (FPD), a substrate for an optical disk, a substrate for a magnetic disk, or a substrate for a solar cell. Background Art

[0002] In the manufacturing process of semiconductor devices, flash lamp annealing (FLA) that heats semiconductor wafers in a very short time has attracted much attention. Flash lamp annealing is a heat treatment technology that heats the surface of a semiconductor wafer in a very short time (less than a few milliseconds) by irradiating a flash of light onto the surface of the semiconductor wafer using a xenon flash lamp (hereinafter referred to as a "flash lamp").

[0003] The radiation spectrum distribution of the xenon flash lamp ranges from the ultraviolet region to the near infrared region, and the wavelength is shorter than that of the conventional halogen lamp, which is roughly consistent with the fundamental absorption band of the silicon semiconductor wafer. Therefore, when the semiconductor wafer is irradiated with flash from the xenon flash lamp, less light is transmitted, and the temperature of the semiconductor wafer can be quickly increased. In addition, it is also known that if the flash irradiation is extremely short, less than a few milliseconds, only the surface of the semiconductor wafer can be selectively heated.

[0004] This flash lamp annealing is used for processing that requires extremely short-term heating, such as activation of impurities implanted into semiconductor wafers. If a flash lamp is irradiated on the surface of a semiconductor wafer into which impurities have been implanted by ion implantation, the surface of the semiconductor wafer can be heated to the activation temperature in an extremely short time, and only activation of the impurities can be performed without causing the impurities to diffuse deeply.

[0005] As an apparatus for performing such flash lamp annealing, a heat treatment apparatus is typically used in which a flash lamp is arranged above a chamber that accommodates semiconductor wafers and a halogen lamp is arranged below (Patent Document 1). In the apparatus disclosed in Patent Document 1, after preheating the semiconductor wafer by light irradiation from the halogen lamp, a flash is irradiated to the surface of the semiconductor wafer from the flash lamp. Preheating by the halogen lamp is performed because it is difficult to bring the surface of the semiconductor wafer to a target temperature by flash irradiation alone.

[0006] However, halogen lamps mainly emit infrared light with a relatively long wavelength. In the spectral absorption rate of silicon semiconductor wafers, the absorption rate of long-wavelength infrared light of 1 μm or more is low in the low-temperature region below 500°C. In other words, semiconductor wafers below 500°C do not absorb much infrared light irradiated from halogen lamps, so they are heated inefficiently in the initial stage of preheating.

[0007] Therefore, Patent Document 2 proposes to preheat semiconductor wafers using LED (Light Emitting Diode) lamps instead of halogen lamps. If the LED lamp emits light with a wavelength of 1 μm or less, even a relatively low-temperature semiconductor wafer can be efficiently heated.

[0008] [Background Technology Literature]

[0009] [Patent Document]

[0010] [Patent Document 1] Japanese Patent Application Publication No. 2011-159713

[0011] [Patent Document 2] Japanese Patent Application Publication No. 2022-106561 Summary of the invention

[0012] [Problems that the invention aims to solve]

[0013] However, since the output of LED lamps is relatively low, it is difficult to heat the semiconductor wafer to the required preheating temperature. In order to heat the semiconductor wafer to the specified preheating temperature using LED lamps, multiple LED lamps need to be configured, which increases the cost and the installation space.

[0014] 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 apparatus capable of efficiently heating a substrate to a high temperature.

[0015] [Technical means to solve the problem]

[0016] In order to solve the above-mentioned problem, the first aspect of the present invention is a heat treatment device for heating a substrate by irradiating light onto the substrate, and the heat treatment device comprises: a chamber for accommodating the substrate; a holding portion for holding the substrate in the chamber; an auxiliary light source for irradiating light onto the substrate held by the holding portion; and a flash lamp for irradiating a flash onto the substrate preheated by the auxiliary light source; and the auxiliary light source comprises a plurality of laser diodes.

[0017] A second aspect is the heat treatment apparatus according to the first aspect, further comprising an optical element for guiding the light emitted from the plurality of laser diodes so as to irradiate the entire surface of the substrate with a uniform illumination distribution.

[0018] Moreover, a third aspect is the heat treatment apparatus according to the first or second aspect, wherein the auxiliary light source further includes a plurality of vertical cavity type surface emitting lasers.

[0019] A fourth aspect is the heat treatment apparatus according to the third aspect, further comprising a homogenizer for homogenizing the light emitted from each of the plurality of vertical cavity type surface emitting lasers.

[0020] Furthermore, a fifth aspect is a heat treatment apparatus according to the third aspect, wherein the plurality of vertical cavity type surface emitting lasers are arranged in a ring shape so as to surround the periphery of the optical element, and irradiate light to the peripheral portion of the substrate.

[0021] In addition, the sixth aspect is a heat treatment device according to the fifth aspect, wherein the auxiliary light source further has an additional vertical cavity type surface emitting laser, which is arranged around the plurality of vertical cavity type surface emitting lasers arranged in a ring shape with an irradiation direction toward the substrate.

[0022] In addition, a seventh aspect is a heat treatment device according to any one of aspects 1 to 5, wherein the auxiliary light source includes a vertical cavity surface emitting laser that irradiates light of different wavelengths and a laser diode that irradiates light of different wavelengths.

[0023] [Effects of the Invention]

[0024] According to the heat treatment device of aspects 1 to 7, since the auxiliary light source for preheating the substrate before flash irradiation has multiple laser diodes, the laser diodes irradiate light with a wavelength shorter than 1 μm and relatively high intensity, which can efficiently heat the substrate to a high temperature.

[0025] In particular, according to the heat treatment device of aspect 5, since a plurality of vertical resonator type surface emitting lasers are arranged in a ring shape surrounding the optical element and irradiate light to the peripheral portion of the substrate, it is possible to supplement the heating of the peripheral portion of the substrate where the temperature drops, and to make the in-plane temperature distribution of the substrate uniform.

[0026] In particular, according to the heat treatment device of aspect 7, since the auxiliary light source includes a vertical resonator type surface emitting laser that irradiates light of different wavelengths and a laser diode that irradiates light of different wavelengths, even in a case where a film with a low absorption rate for light of a specific wavelength is formed on a part of the substrate, the entire surface of the substrate can be uniformly heated to improve the in-plane uniformity of the temperature distribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a longitudinal sectional view showing the structure of the heat treatment apparatus of the present invention.

[0028] Figure 2 It is a perspective view showing the overall appearance of the holding portion.

[0029] Figure 3 This is a top view of the base.

[0030] Figure 4 is a cross-sectional view of the base.

[0031] Figure 5 It is a top view of the transfer mechanism.

[0032] Figure 6 It is a side view of the transfer mechanism.

[0033] Figure 7 It is a plan view showing the arrangement of an optical element and a plurality of VCSELs.

[0034] Figure 8 It is a diagram schematically showing an optical element and irradiation of light by a plurality of VCSELs.

[0035] Fig. 9 This is a diagram showing temperature distribution generated in a semiconductor wafer by irradiation with light from a laser diode.

[0036] Fig.10 It is a diagram showing the structure of a heat treatment apparatus according to a second embodiment.

[0037] Fig.11 It is a plan view showing an example of the arrangement structure of a plurality of laser diodes and a plurality of VCSELs according to the third embodiment.

[0038] Fig.12 It is a plan view showing the arrangement of an optical element and a plurality of VCSELs according to a fourth embodiment.

[0039] Fig.13 This is a diagram schematically showing light irradiation from an optical element and a plurality of VCSELs according to the fourth embodiment.

[0040] Fig.14 It is a diagram showing the configuration of a light source of an auxiliary heating unit in the fifth embodiment. DETAILED DESCRIPTION

[0041] Below, refer to the attached Figure 1The embodiments of the present invention are described in detail. Hereinafter, the expressions (for example, "in one direction", "along one direction", "parallel", "orthogonal", "center", "concentric", "coaxial", etc.) representing relative or absolute positional relationships, unless otherwise specified, not only strictly represent their positional relationships, but also represent the state of relative displacement of angles or distances within the range of functions that can obtain the same degree. In addition, the expressions (for example, "same", "equal", "homogeneous", etc.) representing equal states, unless otherwise specified, not only quantitatively and strictly represent equal states, but also represent the state of difference of tolerance or functions that can obtain the same degree. In addition, the expressions (for example, "circular", "quadrilateral", "cylindrical", etc.) representing shapes, unless otherwise specified, not only strictly represent their shapes geometrically, but also represent the shapes of the range of effects that can obtain the same degree, such as concave-convex or chamfered corners, etc. In addition, the expressions of "prepared", "set", "equipped", "including", "having" constituent elements are not exclusive expressions that exclude the existence of other constituent elements. In addition, the expression "at least one of A, B, and C" includes "only A", "only B", "only C", "any two of A, B, and C", and "all of A, B, and C".

[0042] <First embodiment>

[0043] 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 disk-shaped semiconductor wafer W 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. Figure 1 In the following drawings, the size or number of each component is exaggerated or simplified as necessary to facilitate understanding.

[0044] The heat treatment device 1 includes a chamber 6 for accommodating a semiconductor wafer W, a flash heating unit 5 having a plurality of flash lamps FL built therein, and an auxiliary heating unit 4 having a plurality of VCSELs (Vertical Cavity Surface Emitting Lasers) 45 and a plurality of laser diodes 47. The flash heating unit 5 is provided on the upper side of the chamber 6, and the auxiliary heating unit 4 is provided on the lower side. In addition, the heat treatment device 1 includes a holding unit 7 for holding the semiconductor wafer W in a horizontal position inside the chamber 6, and a transfer mechanism 10 for transferring the semiconductor wafer W between the holding unit 7 and the outside of the device. In addition, the heat treatment device 1 includes a control unit 3 for performing heat treatment of the semiconductor wafer W by controlling each action mechanism provided in the auxiliary heating unit 4, the flash heating unit 5, and the chamber 6.

[0045] 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 close it, and a lower chamber window 64 is installed at the lower opening to close it. The upper chamber window 63 constituting the top of the chamber 6 is a disk-shaped component 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 plate of the chamber 6 is also a disk-shaped component formed of quartz, and functions as a quartz window that allows the light from the auxiliary heating unit 4 to pass into the chamber 6.

[0046] 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. Both the reflection rings 68 and 69 are 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. In other words, the reflection rings 68 and 69 are both installed in the chamber side portion 61 so as to be freely loaded and unloaded. The space surrounded by the inner space of the chamber 6, that is, 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.

[0047] By installing the reflection rings 68 and 69 on the chamber side portion 61, a recessed portion 62 is formed on the inner wall surface of the chamber 6. That is, the recessed 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 installed, the lower end surface of the reflection ring 68, and the upper end surface of the reflection ring 69. The recessed portion 62 is formed in a circular ring shape along the horizontal direction on the inner wall surface of the chamber 6, surrounding 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.

[0048] In addition, a transport opening (furnace port) 66 for carrying in and carrying out semiconductor wafers W in the chamber 6 is formed on the chamber side 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 in from the transport opening 66 through the recess 62 to the heat treatment space 65, and the semiconductor wafer W can be carried out from the heat treatment space 65. In addition, when the gate valve 185 closes the transport opening 66, the heat treatment space 65 in the chamber 6 becomes a closed space.

[0049] In addition, a through hole 61a is formed in the chamber side portion 61. A radiation thermometer 20 is installed at a portion of the outer wall surface of the chamber side portion 61 where the through hole 61a is formed. The through hole 61a is a cylindrical hole for guiding infrared light emitted from the lower surface of a semiconductor wafer W held on a susceptor 74 described later to the radiation thermometer 20. The through hole 61a is arranged obliquely relative to the horizontal direction in such a manner that the axis of the through hole 61a intersects with the main surface of the semiconductor wafer W held on the susceptor 74. Therefore, the radiation thermometer 20 is arranged obliquely below the susceptor 74. A transparent window 21 made of a barium fluoride material is installed at the end of the through hole 61a on the side facing the heat treatment space 65, which allows infrared light in a wavelength range that can be measured by the radiation thermometer 20 to pass through.

[0050] In addition, a gas supply hole 81 for supplying a processing gas to the heat treatment space 65 is formed on the upper part of the inner wall of the chamber 6. The gas supply hole 81 is formed at a position above the recess 62, and can also be provided on the reflection ring 68. The gas supply hole 81 is connected to the gas supply pipe 83 via the buffer space 82 formed in an annular shape inside the side wall of the chamber 6. The gas supply pipe 83 is connected to the processing gas supply source 85. In addition, a valve 84 is inserted in the middle of the path of the gas supply pipe 83. When 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 manner that expands 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), or a reactive gas such as hydrogen (H2) or ammonia (NH3), or a mixed gas (nitrogen in this embodiment) thereof can be used.

[0051] On the other hand, a gas exhaust hole 86 for exhausting the gas in the heat treatment space 65 is formed at the lower part 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 at the reflection ring 69. The gas exhaust hole 86 is connected to the gas exhaust pipe 88 via the 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 part 190. In addition, a valve 89 is inserted 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 to the gas exhaust pipe 88 via the buffer space 87. In addition, the gas supply hole 81 and the gas exhaust hole 86 can be provided in plurality along the circumferential direction of the chamber 6, or can be slit-shaped. In addition, the processing gas supply source 85 and the exhaust part 190 can be a mechanism provided in the heat treatment device 1, or can be equipment in a factory where the heat treatment device 1 is provided.

[0052] 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 base 74. The base ring 71, the connecting part 72, and the base 74 are all formed of quartz. In other words, the holding part 7 is formed of quartz as a whole.

[0053] The base ring 71 is a quartz component in an arc shape with a portion missing from the circular ring. The 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 supported by 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 erected along the circumferential direction of the annular shape. The connecting part 72 is also a quartz component and is fixed to the base ring 71 by welding.

[0054] The base 74 is supported by four connection parts 72 provided on the base ring 71 . Figure 3 74 is a top view of the base. Figure 4 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 formed 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 plane size than the semiconductor wafer W.

[0055] A guide ring 76 is provided on the peripheral portion of the upper surface of the retaining plate 75. The guide ring 76 is a component 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 formed into a tapered surface that widens upward from the retaining plate 75. The guide ring 76 is formed of the same quartz as the retaining plate 75. The guide ring 76 can be welded to the upper surface of the retaining plate 75, or it can be fixed to the retaining plate 75 by a separately processed pin or the like. Alternatively, the retaining plate 75 and the guide ring 76 can be processed as an integral component.

[0056] The area on the upper surface of the holding plate 75 that is inside the guide ring 76 is 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 the present 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 on which the 12 substrate support pins 77 are arranged (the distance between the opposing substrate support pins 77) is smaller than the diameter of the semiconductor wafer W, and if the diameter of the semiconductor wafer W is φ300 mm, it is φ270 mm to φ280 mm (φ270 mm in the present embodiment). Each substrate support pin 77 is formed of quartz. A plurality of substrate support pins 77 may be set on the upper surface of the holding plate 75 by welding, or may be processed integrally with the holding plate 75.

[0057] return Figure 2 , the four connecting parts 72 erected on the base ring 71 are fixed to the peripheral part of the holding plate 75 of the base 74 by welding. That is, the base 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 base 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 is a horizontal plane.

[0058] The semiconductor wafer W carried into the chamber 6 is placed and held in a horizontal posture on a pedestal 74 of a holding portion 7 installed in the chamber 6. At this time, the semiconductor wafer W is supported and held on the pedestal 74 by 12 substrate support pins 77 erected on a holding plate 75. 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 posture by the 12 substrate support pins 77.

[0059] The semiconductor wafer W is supported by the plurality of substrate support pins 77 with a predetermined gap between it and the holding surface 75a of the holding plate 75. The thickness of the guide ring 76 is greater than the height of the substrate support pins 77. Therefore, the guide ring 76 prevents the semiconductor wafer W supported by the plurality of substrate support pins 77 from being displaced in the horizontal direction.

[0060] In addition, if Figure 2 and Figure 3As shown, an opening 78 is formed through the top and bottom of the holding plate 75 of the base 74. The opening 78 is provided so that the radiation thermometer 20 receives the radiation light (infrared light) emitted from the lower surface of the semiconductor wafer W. That is, the radiation thermometer 20 receives the light emitted from the lower surface of the semiconductor wafer W through the transparent window 21 installed in the opening 78 and the through hole 61a of the chamber side 61, and measures the temperature of the semiconductor wafer W. In addition, the holding plate 75 of the base 74 is penetrated by four through holes 79 for the lifting pins 12 of the transfer mechanism 10 described later to pass the semiconductor wafer W.

[0061] 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 in an arc shape along the substantially annular recess 62. Two lifting pins 12 are erected on each transfer arm 11. The transfer arms 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 enables a pair of transfer arms 11 to be in a transfer action position ( Figure 5 The solid line position) and the retreat position ( Figure 5 As the horizontal moving mechanism 13, each transfer arm 11 can be rotated separately by an independent motor, or a link mechanism can be used to rotate a pair of transfer arms 11 in conjunction with one motor.

[0062] In addition, the pair of transfer arms 11 are moved up and down together with the horizontal moving mechanism 13 through 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 lifting pins 12 pass through the through holes 79 (refer to Figure 2 , 3 ), the upper end of the lifting pin 12 protrudes from the upper surface of the base 74. On the other hand, when the lifting mechanism 14 causes the pair of transfer arms 11 to descend in the transfer action position and pulls out the lifting pin 12 from the through hole 79, and the horizontal moving mechanism 13 moves in a manner to open the pair of transfer arms 11, 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 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 exhaust the atmosphere around the drive portion of the transfer mechanism 10 to the outside of the chamber 6.

[0063] return Figure 1The 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 upper part of the light source, on the inner side of a housing 51. In addition, a light irradiation window 53 is installed at the bottom of the housing 51 of the flash heating unit 5. The light irradiation window 53 constituting the bottom plate 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 irradiation window 53 is opposed to 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 irradiation window 53 and the upper chamber window 63.

[0064] The plurality of flash lamps FL are rod-shaped lamps each having a long cylindrical shape, and are arranged in a plane in such a manner that their respective length directions are parallel to each other along the main surface (that is, 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. The area where the plurality of flash lamps FL are arranged is larger than the plane size of the semiconductor wafer W.

[0065] The xenon flash lamp FL includes: a cylindrical glass tube (discharge tube) in which xenon gas is sealed and an anode and a cathode connected to a capacitor are arranged at both ends; and a trigger electrode attached to the outer peripheral surface of the glass tube. Since xenon gas is an electrical insulator, even if electric charge is accumulated in the capacitor, electricity does not flow in the glass tube under normal conditions. However, when a high voltage is applied to the trigger electrode to break the insulation, the electricity accumulated in the capacitor will flow into the glass tube instantly, and light will be emitted by the excitation of xenon atoms or molecules at this time. In such a xenon flash lamp FL, since the electrostatic energy accumulated in the capacitor in advance is converted into an extremely short light pulse of 0.1 milliseconds to 100 milliseconds, it has the characteristic of being able to emit extremely strong light compared to a continuously lit light source such as a halogen lamp. In other words, the flash lamp FL is a pulse light lamp that emits light instantly in an extremely short time of less than 1 second. In addition, the light emission time of the flash lamp FL can be adjusted by the coil constant of the lamp power supply that supplies power to the flash lamp FL.

[0066] In addition, the reflector 52 is provided above the plurality of flash lamps FL so as to cover the entirety thereof. The basic function of the reflector 52 is to reflect the flash emitted from the plurality of flash lamps FL to 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.

[0067] The auxiliary heating unit 4 is provided on the opposite side of the flash heating unit 5 across the chamber 6, that is, below the chamber 6. The auxiliary heating unit 4 includes a cabinet 48 having a plurality of laser diodes 47 built therein, an optical element 49, and a plurality of VCSELs 45. The auxiliary heating unit 4 is an auxiliary light source that irradiates a heat treatment space 65 with light from below the chamber 6 through a lower chamber window 64 using a plurality of laser diodes 47 and a plurality of VCSELs 45 to heat the semiconductor wafer W.

[0068] Figure 7 4 is a top view showing the configuration of the optical element 49 and the plurality of VCSELs 45. The optical element 49 of the present embodiment is a quartz component having a roughly cylindrical shape, and is a diffractive optical element (DOE: Diffractive Optical Element) that utilizes the diffraction phenomenon of light. The optical element 49 is arranged below the central portion of the semiconductor wafer W held by the holding portion 7. On the other hand, the plurality of VCSELs 45 are arranged in a circular ring shape so as to surround the periphery of the optical element 49. The number of VCSELs 45 arranged in a circular ring shape can be set to an appropriate number. The plurality of VCSELs 45 are arranged below the peripheral portion of the semiconductor wafer W held by the holding portion 7.

[0069] Figure 8 4 is a diagram schematically showing the irradiation of light from an optical element 49 and a plurality of VCSELs 45. The lower end surface of the optical element 49 is connected to a cabinet 48 via an optical fiber 46. A plurality of laser diodes 47 ( Figure 1 ). The laser diode 47 is an element that causes laser oscillation by flowing current in a semiconductor, and is also called a semiconductor laser. The laser diode 47 has a high output conversion efficiency, can emit high-intensity light, and has a longer life than an LED. The lasers emitted from multiple laser diodes 47 are focused and synthesized in a cabinet 48, and guided to an optical element 49 by an optical fiber 46.

[0070] Generally, the directivity of laser light is high, and the laser light emitted from the plurality of laser diodes 47 and incident on the optical element 49 also has the property of almost not expanding but going straight. The optical element 49 is a diffraction optical element that diffracts the incident light by micro-machining a quartz component and outputs light of various patterns. The optical element 49 spatially branches the laser light incident from the lower end face guided by the optical fiber 46, and emits it in an expanded manner from the upper end face. In other words, the laser light with high directivity guided by the optical fiber 46 from the cabinet 48 is set to be light that is diffracted by the optical element 49 and travels in an expanded manner. Thus, the light emitted from the upper end face of the optical element 49 is irradiated onto the entire lower surface of the semiconductor wafer W held by the holding portion 7.

[0071] In addition, the intensity distribution of the laser light emitted from the laser diode 47 and guided by the optical fiber 46 is close to a Gaussian distribution. That is, the intensity of the laser light is highest near the center of the optical axis, and the intensity decreases as it moves away from the optical axis. The optical element 49 also has the function of making the intensity distribution of the incident light uniform. Therefore, the intensity distribution of the laser light incident on the optical element 49 is made uniform, and the optical element 49 irradiates the lower surface of the semiconductor wafer W with light having a uniform illumination distribution.

[0072] On the other hand, VCSEL (Vertical Cavity Surface Emitting Laser) 45 is a type of semiconductor laser that emits light in a vertical direction relative to the surface of the semiconductor substrate. VCSEL 45 can emit light with relatively high intensity and emit light with high directivity. In other words, the irradiation area of ​​VCSEL 45 is small. A plurality of VCSELs 45 are arranged below the peripheral portion of the semiconductor wafer W held by the holding portion 7, and light is emitted from each VCSEL 45 in the vertical direction upward. Therefore, light is irradiated from the optical element 49 to the entire lower surface of the semiconductor wafer W, while light is irradiated from the VCSEL 45 to the peripheral portion of the semiconductor wafer W.

[0073] In this embodiment, the laser diode 47 emits light with a wavelength of 960 nm to 985 nm. The VCSEL 45 emits light with a wavelength of 930 nm to 940 nm. Both the laser diode 47 and the VCSEL 45 are continuous lighting lamps that emit light continuously for at least 1 second.

[0074] The control unit 3 controls the 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 CPU (Central Processing Unit) as a circuit for performing various calculations, a ROM (Read Only Memory) as a read-only memory for storing basic programs, a RAM (Random Access Memory) as a readable and writable memory for storing various information, and a magnetic disk for storing control software or data. The heat treatment device 1 is processed by executing a predetermined processing program by the CPU of the control unit 3.

[0075] In addition to the above-mentioned configuration, the heat treatment apparatus 1 is provided with various cooling structures to prevent the auxiliary heating unit 4, the flash heating unit 5, and the chamber 6 from overheating due to the heat energy generated by the laser diode 47, the VCSEL 45, 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 auxiliary heating unit 4 and the flash heating unit 5 are air-cooled structures that form a gas flow inside to 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 unit 5 and the upper chamber window 63.

[0076] Next, the processing actions of the heat treatment device 1 are described. Here, a typical heat treatment action for a normal semiconductor wafer (product wafer) W that becomes a product is described. The semiconductor wafer W that becomes the processing object is a semiconductor substrate of silicon (Si) implanted with impurities by ion implantation as a previous step. The activation of the impurities is performed by annealing treatment of the heat treatment device 1. The processing sequence of the semiconductor wafer W described below is performed by controlling the various action mechanisms of the heat treatment device 1 by the control unit 3.

[0077] First, before processing the semiconductor wafer W, the valve 84 for gas supply is opened, and the valve 89 for exhaust is opened, and the supply and exhaust of the chamber 6 are started. When the valve 84 is opened, nitrogen gas is supplied from the gas supply hole 81 to the heat treatment space 65. In addition, when the valve 89 is opened, the gas in the chamber 6 is exhausted from the gas exhaust hole 86. As a result, the nitrogen gas supplied from the upper part of the heat treatment space 65 in the chamber 6 flows downward and is exhausted from the lower part of the heat treatment space 65.

[0078] 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 device. At this time, as the semiconductor wafer W is transferred in, the atmosphere outside the device may be brought in, but since nitrogen gas is continuously supplied to the chamber 6, nitrogen gas flows out from the transfer opening 66, and the introduction of such external atmosphere can be suppressed to a minimum.

[0079] The semiconductor wafer W carried in by the transfer robot stops at a position just above the holding portion 7. Then, the pair of transfer arms 11 of the transfer mechanism 10 are horizontally moved from the retracted position to the transfer operation position and raised, so that the lift pins 12 protrude from the upper surface of the holding plate 75 of the base 74 through the through holes 79 to receive the semiconductor wafer W. At this time, the lift pins 12 are raised to a position higher than the upper ends of the substrate support pins 77.

[0080] After placing the semiconductor wafer W on the lifting pins 12, the transport robot withdraws from the heat treatment space 65 and closes the transport opening 66 by the gate valve 185. Then, by lowering the pair of transfer arms 11, the semiconductor wafer W is handed over from the transfer mechanism 10 to the base 74 of the holding portion 7, 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 is held on the base 74. In addition, the semiconductor wafer W is held on the holding portion 7 with the surface on which the pattern is formed 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 that have descended to the bottom of the base 74 retreat to the retreat position, that is, the inner side of the recess 62, by the horizontal moving mechanism 13.

[0081] After the semiconductor substrate W is held in a horizontal position from below by the base 74 of the holding part 7 formed of quartz, light is irradiated from the auxiliary heating part 4 to the semiconductor wafer W to start preheating (auxiliary heating). The lasers emitted from the multiple laser diodes 47 are focused and synthesized in the cabinet 48, and guided to the lower end face of the optical element 49 by the optical fiber 46. The optical element 49 diffracts the laser light incident from the lower end face to make the intensity distribution uniform, and emits it from the upper end face in an expanded manner in the direction of travel. The light emitted from the optical element 49 passes through the lower chamber window 64 and the base 74 formed of quartz, and irradiates the entire lower surface of the semiconductor wafer W with a uniform illumination distribution.

[0082] However, even if the laser diode 47 irradiates the entire lower surface of the semiconductor wafer W with uniform illumination distribution, the semiconductor wafer W may generate the following Fig. 9 The non-uniform temperature distribution shown in FIG. That is, a temperature distribution is generated in which the temperature of the peripheral portion is relatively lower than that of the central portion of the semiconductor wafer W. Although light with uniform illumination distribution is irradiated, the temperature distribution is non-uniform because the amount of heat dissipated to the outside of the peripheral portion of the semiconductor wafer W is greater than that of the central portion, and the temperature is easily reduced.

[0083] Therefore, in the first embodiment, a plurality of VCSELs 45 are provided, and light is irradiated from these VCSELs to the peripheral portion of the semiconductor wafer W. The VCSELs 45 irradiate light with relatively high intensity and high directivity to the peripheral portion of the semiconductor wafer W. Thus, light is irradiated from the plurality of VCSELs 45 only to the peripheral portion of the semiconductor wafer W where a relatively low temperature has occurred, and the temperature drop of the peripheral portion is eliminated, so that the temperature distribution on the entire surface of the semiconductor wafer W is uniform.

[0084] By receiving light irradiation from multiple laser diodes 47 and multiple VCSELs 45, the semiconductor wafer W is preheated and the temperature rises. The temperature of the semiconductor wafer W heated by light irradiation from the auxiliary heating unit 4 is measured by the 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 heated by light irradiation from the auxiliary heating unit 4 reaches the specified preheating temperature T1, and controls the output of the laser diode 47 and the VCSEL 45. That is, the control unit 3 performs feedback control on the output of the laser diode 47 and the VCSEL 45 based on the measured value according to the radiation thermometer 20 so that the temperature of the semiconductor wafer W becomes the preheating temperature T1. The preheating temperature T1 is about 200°C to 800°C, where there is no need to worry about the diffusion of impurities added to the semiconductor wafer W due to heat, and is preferably about 350°C to 600°C (600°C in this embodiment).

[0085] After the temperature of the semiconductor wafer W reaches the preheating temperature T1, the control unit 3 temporarily maintains the semiconductor wafer W at the preheating temperature T1. Specifically, when the temperature of the semiconductor wafer W measured by the radiation thermometer 20 reaches the preheating temperature T1, the control unit 3 adjusts the output of the laser diode 47 and the VCSEL 45 to maintain the temperature of the semiconductor wafer W approximately at the preheating temperature T1.

[0086] When 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 flashes the surface of the semiconductor wafer W held by the susceptor 74. At this time, a part of the flash emitted from the flash lamp FL is directed directly into the chamber 6, and another part is temporarily reflected by the reflector 52 and then directed into the chamber 6, and the semiconductor wafer W is flash heated by the flash irradiation.

[0087] Since flash heating is performed by irradiating a flash (flash light) from the flash lamp FL, the surface temperature of the semiconductor wafer W can be increased in a short time. That is, the flash irradiated from the flash lamp FL is an extremely short strong flash that converts the electrostatic energy previously accumulated in the capacitor into an extremely short light pulse, and the irradiation time is about 0.1 milliseconds or more and 100 milliseconds or less. Then, the surface temperature of the semiconductor wafer W that is flash-heated by the flash irradiation from the flash lamp FL instantly rises to a processing temperature T2 of more than 1000°C, and after the impurities injected into the semiconductor wafer W are activated, the surface temperature drops rapidly. In this way, in the heat treatment device 1, since the surface temperature of the semiconductor wafer W can be raised and lowered in an extremely short time, the impurities injected into the semiconductor wafer W can be suppressed from diffusing due to heat and the impurities can be activated. In addition, since the time required for the activation of the impurities is extremely short compared to the time required for the thermal diffusion, the activation is completed even in a short time of about 0.1 milliseconds to 100 milliseconds where diffusion does not occur.

[0088] After the flash heating treatment is completed, the light irradiation from the auxiliary heating unit 4 is also stopped after a prescribed time. As a result, the semiconductor wafer W is rapidly cooled from the preheating temperature T1. The temperature of the semiconductor wafer W during the cooling period is measured by the radiation thermometer 20, and the measurement result is transmitted to the control unit 3. The control unit 3 monitors whether the temperature of the semiconductor wafer W drops to a prescribed temperature based on the measurement result of the radiation thermometer 20. Then, after the temperature of the semiconductor wafer W drops below the prescribed temperature, the pair of transfer arms 11 of the transfer mechanism 10 moves horizontally from the retreat position to the transfer action position again and rises, thereby causing the lifting pins 12 to protrude from the upper surface of the base 74 and receive the heat-treated semiconductor wafer W from the base 74. Next, the transport opening 66 closed by the gate valve 185 is opened, and the semiconductor wafer W placed on the lifting pins 12 is moved out of the chamber 6 by the transport robot outside the device, and the heating treatment of the semiconductor wafer W is completed.

[0089] In the first embodiment, during preheating of the semiconductor wafer W, the entire surface of the semiconductor wafer W is irradiated with light with a uniform illumination distribution by a plurality of laser diodes 47, and the peripheral portion of the semiconductor wafer W is irradiated with light from a plurality of VCSELs 45. The laser diode 47 irradiates the semiconductor wafer W with light having a wavelength shorter than 1 μm. In the spectral absorption rate of the semiconductor wafer W of silicon, although the absorption rate of infrared light exceeding a wavelength of 1 μm in the low temperature domain below 500°C is low, the absorption rate of light having a wavelength below 1 μm is relatively high. That is, even in the low temperature domain below 500°C, the semiconductor wafer W can well absorb the light irradiated from the laser diode 47. Therefore, even when the temperature of the semiconductor wafer W is below 500°C in the initial stage of preheating, the semiconductor wafer W can be efficiently heated by the laser diode 47.

[0090] In addition, the laser diode 47 emits light of higher intensity than an LED. Therefore, the semiconductor wafer W can be heated to a desired preheating temperature T1 by the laser diode 47. That is, the semiconductor wafer W can be efficiently heated to a high temperature by irradiation with light from the laser diode 47.

[0091] However, even if the laser diode 47 irradiates the entire lower surface of the semiconductor wafer W with uniform illumination distribution, an uneven temperature distribution will occur in which the temperature of the peripheral portion of the semiconductor wafer W that is easy to cool is lower than the temperature of the central portion. Therefore, a plurality of VCSELs 45 arranged in a circular ring below the peripheral portion of the semiconductor wafer W irradiate the peripheral portion with light having a high directivity. Since the VCSELs 45 can also emit light with a relatively high intensity, the heating of the peripheral portion of the semiconductor wafer W that has dropped in temperature can be supplemented, and the in-plane temperature distribution of the semiconductor wafer W can be made uniform.

[0092] <Second Embodiment>

[0093] Next, a second embodiment of the present invention will be described. Fig.10 1 is a diagram showing the configuration of a heat treatment apparatus according to Embodiment 2. In Embodiment 2, a homogenizer 43 is provided to make the distribution of light emitted from each of a plurality of VCSELs 45 uniform.

[0094] The homogenizer 43 is a quartz member provided between the VCSEL 45 and the lower chamber window 64 of the chamber 6. The homogenizer 43 is also a diffractive optical element, and makes the intensity distribution of light emitted from the corresponding VCSEL 45 uniform.

[0095] VCSEL 45 is also a type of semiconductor laser. Since it emits light with relatively high directivity, its light intensity distribution is close to Gaussian distribution. Therefore, when light is directly irradiated from VCSEL 45 to semiconductor wafer W, there are areas with high illumination and areas with low illumination in the irradiated surface of semiconductor wafer W, which may cause uneven illumination. The intensity distribution of light emitted from VCSEL 45 is homogenized by homogenizer 43, thereby eliminating uneven illumination in the irradiated surface of semiconductor wafer W and making the irradiated surface uniform in illumination distribution. As a result, the in-plane temperature distribution of semiconductor wafer W during preheating is also made more uniform.

[0096] The configuration of the heat treatment apparatus of the second embodiment is the same as that of the heat treatment apparatus 1 of the first embodiment except that the homogenizer 43 is provided. The processing procedure of the semiconductor wafer W in the heat treatment apparatus of the second embodiment is also the same as that of the first embodiment.

[0097] <Third Embodiment>

[0098] Next, a third embodiment of the present invention will be described. In the third embodiment, the optical element 49 is not provided, and the semiconductor wafer W is directly irradiated with light from the plurality of laser diodes 47 .

[0099] Fig.11 1 is a top view showing an example of the configuration of multiple laser diodes 47 and multiple VCSELs 45 in the third embodiment. Multiple laser diodes 47 are arranged in a plane with uniform density in a circular area below the central part of the semiconductor wafer W held by the holding portion 7. Multiple VCSELs 45 are arranged with uniform density in an annular area surrounding the circular area where the multiple laser diodes 47 are arranged. The annular area where the multiple VCSELs 45 are arranged is below the peripheral portion of the semiconductor wafer W. That is, in the auxiliary heating portion 4 of the third embodiment, multiple laser diodes 47 are arranged in the center, and multiple VCSELs 45 are arranged in the peripheral portion.

[0100] Although the laser diode 47 emits laser light with high directivity, Fig.11 As shown, by arranging a plurality of laser diodes 47 at a uniform density in a circular area, the entire lower surface of the semiconductor wafer W can be irradiated with light. However, even if a plurality of laser diodes 47 are arranged at a uniform density in a circular area, as in the first embodiment, an uneven temperature distribution occurs in which the temperature of the peripheral portion of the semiconductor wafer W is lower than the temperature of the central portion. Therefore, a plurality of VCSELs 45 are arranged in a manner opposite to the peripheral portion of the semiconductor wafer W, and light is irradiated from them to the peripheral portion of the semiconductor wafer W. As a result, the peripheral portion of the semiconductor wafer W, whose temperature is easily lowered, can be strongly heated, the temperature drop of the peripheral portion can be eliminated, and the temperature distribution in the surface of the semiconductor wafer W can be made uniform.

[0101] The remaining configuration of the third embodiment is the same as that of the first embodiment. In addition, the processing procedure of the semiconductor wafer W in the third embodiment is also the same as that of the first embodiment.

[0102] <Fourth embodiment>

[0103] Next, a fourth embodiment of the present invention will be described. In the fourth embodiment, an additional VCSEL 45 is provided in addition to the plurality of VCSELs 45 of the first embodiment.

[0104] Fig.12 4 is a top view showing the arrangement of the optical element 49 and the plurality of VCSELs 45 according to the fourth embodiment. Fig.13Schematically showing light irradiation from the optical element 49 and the plurality of VCSELs 45 in the fourth embodiment. In the fourth embodiment, additional VCSELs 45 are further arranged around the plurality of VCSELs 45 arranged in an annular shape in the first embodiment. The additional plurality of VCSELs 45 are obliquely arranged in a region outside the semiconductor wafer W held by the holding portion 7.

[0105] In more detail, similarly to the first embodiment, a plurality of VCSELs 45 are arranged in a circular ring shape below the peripheral portion of the semiconductor wafer W held by the holding portion 7. In addition, a plurality of additional VCSELs 45 are arranged around the plurality of VCSELs 45 arranged in a circular ring shape and in an area outside the semiconductor wafer W. The plurality of additional VCSELs 45 arranged in an area outside the semiconductor wafer W are arranged obliquely in such a manner that their irradiation directions face the lower surface of the semiconductor wafer W. The configuration of the fourth embodiment and the processing sequence of the semiconductor wafer W other than the arrangement of the plurality of additional VCSELs 45 are the same as those of the first embodiment.

[0106] In the fourth embodiment, similarly to the first embodiment, the entire surface of the semiconductor wafer W is irradiated with light with a uniform illumination distribution by a plurality of laser diodes 47, and the peripheral portion of the semiconductor wafer W is irradiated with light from a plurality of VCSELs 45 arranged in an annular shape. Thus, the peripheral portion of the semiconductor wafer W, which is prone to temperature drop, can be irradiated with light with high directivity from the VCSELs 45 to strongly heat the peripheral portion, and the in-plane temperature distribution of the semiconductor wafer W can be made uniform. In addition, in the fourth embodiment, by irradiating the in-plane of the semiconductor wafer W with additional light from the additional VCSELs 45, the semiconductor wafer W can be heated to a high temperature more efficiently.

[0107] <Fifth embodiment>

[0108] Next, a fifth embodiment of the present invention will be described. In the fifth embodiment, a fiber laser is used to amplify laser light emitted from a laser diode 47 using an optical fiber doped with a rare earth element.

[0109] Fig.14 FIG. 5 is a diagram showing the structure of the light source of the auxiliary heating unit according to the fifth embodiment. Fig.14In the figure, the same reference numerals are given to the same elements as those in the first embodiment. A plurality of laser diodes 47, a pump combiner 44 and a rare earth-doped fiber 41 are provided in a cabinet 48. The rare earth-doped optical fiber 41 is an optical fiber in which a rare earth is doped in the core. As the rare earth doped, for example, ytterbium (Yb), neodymium (Nd), thulium (Tm), and erbium (Er) are used. A fiber jacket is doubled on the outside of the core. In addition, reflectors or fiber Bragg gratings (FBG: Fiber Bragg Grating) not shown in the figure are provided at both ends of the rare earth-doped fiber 41.

[0110] The lasers emitted from a plurality of laser diodes 47 are synthesized by a pump combiner 44. The synthesized laser is incident on the rare-earth doped optical fiber 41 as excitation light. The excitation light excites the doped rare-earth element, thereby emitting laser light. In other words, the laser light is amplified. The emitted laser light is guided to the optical element 49 through the optical fiber 46. Then, as in the first embodiment, the light emitted from the upper end face of the optical element 49 is irradiated onto the lower surface of the semiconductor wafer W. In an optical fiber laser such as the fifth embodiment, since the excitation and emission are performed in a thinner core in the rare-earth doped optical fiber 41, the laser light amplification efficiency is good.

[0111] <Example of variation>

[0112] The embodiments of the present invention have been described above, but the present invention can make various changes other than those described above without departing from the main purpose. For example, in the embodiment described, the auxiliary heating section 4 is provided with a laser diode 47 and a VCSEL 45, but it is also possible to replace them and only provide a plurality of laser diodes 47 in the auxiliary heating section 4. In the case described, the semiconductor wafer W is preheated only by a plurality of laser diodes 47. Since the laser diode 47 irradiates the semiconductor wafer W with light having a wavelength shorter than 1 μm, the light is also well absorbed by the relatively low temperature semiconductor wafer W in the initial stage of preheating. In addition, the laser diode 47 emits light with a relatively high intensity. That is, compared with the existing halogen lamp, the laser diode 47 can efficiently heat the semiconductor wafer W to a high temperature.

[0113] When only the laser diode 47 is provided without the VCSEL 45 in the auxiliary heating unit 4, an optical element 49 may be provided as in the first embodiment, or a plurality of laser diodes 47 may be arranged in a plane as in the third embodiment. When the optical element 49 is provided, it is preferable to diffract the incident light in such a manner that the peripheral portion of the semiconductor wafer W is irradiated with relatively strong light intensity distribution. Thus, the in-plane temperature distribution of the semiconductor wafer W can be made uniform.

[0114] In addition, in the above-described embodiment, the wavelength of light irradiated from the plurality of laser diodes 47 and the plurality of VCSELs 45 is set to a single wavelength, but instead, at least one of the plurality of laser diodes 47 and the plurality of VCSELs 45 may irradiate light of different wavelengths. That is, laser diodes 47 irradiating light of different wavelengths and / or VCSELs 45 irradiating light of different wavelengths may be provided in the auxiliary heating portion 4. When light of a single wavelength is irradiated from the plurality of laser diodes 47 and the plurality of VCSELs 45, in the case where a film having a low absorption rate for light of the wavelength is formed on a portion of the semiconductor wafer W, only the temperature of the portion becomes relatively low, and there is a concern that the in-plane uniformity of the temperature distribution may be impaired. If light of multiple wavelengths is irradiated from the plurality of laser diodes 47 and / or the plurality of VCSELs 45, even in the case where a film having a low absorption rate for light of a specific wavelength is formed on a portion of the semiconductor wafer W, the entire surface of the semiconductor wafer W can be uniformly heated, thereby improving the in-plane uniformity of the temperature distribution.

[0115] In addition, the optical element 49 is not limited to a diffractive optical element, and may be an element that adjusts the optical path by refraction, for example.

[0116] Alternatively, the optical element 49 may not be provided, and the light guided by the optical fiber 46 may be directly irradiated onto the semiconductor wafer W.

[0117] In addition, in each of the above embodiments, the auxiliary heating unit 4 is provided at the lower side of the chamber 6, but the present invention is not limited thereto, and the auxiliary heating unit 4 including a plurality of laser diodes 47 and a plurality of VCSELs 45 may be provided at the upper side of the chamber 6. In this case, the semiconductor wafer W is preheated by light irradiation from the laser diodes 47 and VCSELs 45 at the upper side of the chamber 6.

[0118] In the above embodiment, the VCSEL 45 is disposed opposite to the peripheral portion of the semiconductor wafer W, but the present invention is not limited thereto, and the VCSEL 45 may be disposed opposite to a portion of the semiconductor wafer W where a temperature drop is likely to occur during preheating.

[0119] In the above embodiment, the flash heating unit 5 includes 30 flash lamps FL, but the present invention is not limited thereto and the number of flash lamps FL may be any number. The flash lamps FL are not limited to xenon flash lamps and may be krypton flash lamps.

[0120] [Explanation of Symbols]

[0121] 1 Heat treatment device

[0122] 3. Control Unit

[0123] 4 Auxiliary heating unit

[0124] 5 Flash heating unit

[0125] 6 Chamber

[0126] 7. Maintaining part

[0127] 10 Transfer mechanism

[0128] 20 Radiation Thermometer

[0129] 43 Homogenizer

[0130] 45 VCSEL

[0131] 47 Laser diode

[0132] 49 Optical Components

[0133] 65 Heat treatment space

[0134] 74 Base

[0135] FL Flash

[0136] W Semiconductor wafer.

Claims

1. A heat treatment apparatus, the heat treatment apparatus heating a substrate by irradiating the substrate with light, comprising: a chamber for receiving a substrate; a holding portion for holding the substrate in the chamber; an auxiliary light source, disposed at one side of the chamber, for irradiating light to the substrate held by the holding portion; and a flash lamp, disposed at the other side of the chamber, irradiating a flash to the substrate preheated by the auxiliary light source; and The auxiliary light source includes a plurality of laser diodes.

2. The heat treatment device according to claim 1, further comprising: The optical element guides the light emitted from the plurality of laser diodes so as to illuminate the entire surface of the substrate with a uniform illumination distribution.

3. The heat treatment device according to claim 2, wherein The auxiliary light source further includes a plurality of vertical resonator type surface emitting lasers.

4. The heat treatment device according to claim 3, further comprising: The homogenizer makes the light emitted from each of the plurality of vertical cavity type surface emitting lasers uniform.

5. The heat treatment device according to claim 3, wherein The plurality of vertical cavity type surface emitting lasers are arranged in a ring shape so as to surround the periphery of the optical element and irradiate light to the peripheral portion of the substrate.

6. The heat treatment device according to claim 5, wherein The auxiliary light source further includes an additional vertical cavity type surface emitting laser that is obliquely provided around the plurality of vertical cavity type surface emitting lasers arranged in a ring shape so that the irradiation direction faces the substrate.

7. The heat treatment device according to claim 3, wherein The auxiliary light source includes a vertical cavity surface emitting laser that radiates light of different wavelengths and a laser diode that radiates light of different wavelengths.

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