Heat treatment equipment

Abstract

To provide a thermal treatment device that can suppress the increase in size and cost of a power supply circuit.SOLUTION: In an auxiliary heating portion where a semiconductor wafer is preheated, a plurality of VCSELs 45 are arranged to surround a plurality of LED lamps 47 arranged in a circular area. The plurality of LED lamps 47 irradiate the entire surface of the semiconductor wafer with light, the plurality of VCSELs 45 that emit relatively highly directional light irradiate the peripheral edge of the semiconductor wafer where the temperature tends to drop with light. A common power supply circuit 90 is provided for the plurality of LED lamps 47 and the plurality of VCSELs 45 that irradiate the peripheral edge of the semiconductor wafer with light. Since the single power supply circuit 90 supplies power to two different types of light sources and collectively controls them, it is possible to suppress the increase in size and cost of the power supply circuit.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to a heat treatment apparatus that heats a substrate by irradiating the substrate with light. The substrates to be processed include, for example, semiconductor wafers, substrates for liquid crystal display devices, substrates for flat panel displays (FPDs), substrates for optical disks, substrates for magnetic disks, or substrates for solar cells.

Background Art

[0002] In the manufacturing process of semiconductor devices, flash lamp annealing (FLA) that heats a semiconductor wafer in an extremely short time has attracted attention. Flash lamp annealing is a heat treatment technique that irradiates flash light onto the surface of a semiconductor wafer using a xenon flash lamp (hereinafter simply referred to as "flash lamp" when referring to a xenon flash lamp), thereby raising the temperature of only the surface of the semiconductor wafer to a high temperature in an extremely short time (several milliseconds or less).

[0003] The emission spectral distribution of a xenon flash lamp is from the ultraviolet region to the near-infrared region, and its wavelength is shorter than that of a conventional halogen lamp, and almost coincides with the fundamental absorption band of a silicon semiconductor wafer. Therefore, when flash light is irradiated from a xenon flash lamp onto a semiconductor wafer, there is little transmitted light and the semiconductor wafer can be rapidly heated. It has also been found that if flash light is irradiated for an extremely short time of several milliseconds or less, only the vicinity of the surface of the semiconductor wafer can be selectively heated.

[0004] Such flash lamp annealing is used for processes that require heating in an extremely short time, for example, typically for activating impurities implanted in a semiconductor wafer. If flash light is irradiated from a flash lamp onto the surface of a semiconductor wafer into which impurities have been implanted by ion implantation, the temperature of the surface of the semiconductor wafer can be raised to the activation temperature in an extremely short time, and only impurity activation can be performed without deeply diffusing the impurities.

[0005] Typically, a heat treatment apparatus is used to perform such flash lamp annealing, which has a flash lamp above a chamber containing a semiconductor wafer and a halogen lamp below it (for example, Patent Document 1). In the apparatus disclosed in Patent Document 1, the semiconductor wafer is preheated by light irradiation from the halogen lamp, and then the surface of the semiconductor wafer is irradiated with flash light from the flash lamp. Preheating with the halogen lamp is performed because the surface of the semiconductor wafer does not easily reach the target temperature with flash light irradiation alone. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2011-159713 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] However, when preheating is performed using a halogen lamp, a certain amount of time is required from the time the halogen lamp is turned on until the target output is reached, and heat radiation continues for a while even after the halogen lamp is turned off. This has the problem that the diffusion length of impurities injected into the semiconductor wafer becomes relatively long.

[0008] Furthermore, halogen lamps primarily emit infrared light with relatively long wavelengths. In the spectral absorption rate of silicon semiconductor wafers, the absorption rate of infrared light with wavelengths of 1 μm or longer is low in the low-temperature range below 500°C. In other words, semiconductor wafers below 500°C do not absorb much infrared light irradiated from halogen lamps, resulting in inefficient heating in the initial stages of preheating.

[0009] For this reason, in recent years, the use of multiple LED lamps for preheating semiconductor wafers has been considered. LED lamps have faster power rise and fall times compared to halogen lamps. Also, LED lamps mainly emit visible light. Therefore, even with semiconductor wafers at relatively low temperatures below 500°C, the absorption rate of light irradiated from LED lamps is high, and by using LED lamps, heating can be performed efficiently even in the initial stages of preheating.

[0010] Regardless of whether a halogen lamp or an LED lamp is used as the light source for preheating a semiconductor wafer, heat escapes from the periphery of the semiconductor wafer, resulting in an uneven temperature distribution where the temperature at the periphery is relatively lower than that at the center. In recent years, semiconductor manufacturing processes have become increasingly complex, and consequently, the manufacturing cost per semiconductor wafer has continued to rise. Therefore, there is a strong demand to increase the yield rate of good chips extracted from a single semiconductor wafer, and maintaining uniformity of the in-plane temperature distribution is crucial for this purpose. To achieve a uniform in-plane temperature distribution, it is conceivable to install an additional light source that irradiates the periphery of the semiconductor wafer exclusively during preheating. However, installing such an additional light source would require multiple power supply circuits, leading to problems of increased size and cost of the power supply circuits.

[0011] This invention has been made in view of the above problems, and aims to provide a heat treatment apparatus that can suppress the increase in size and cost of the power supply circuit. [Means for solving the problem]

[0012] To solve the above problems, the invention of claim 1 provides a heat treatment apparatus for heating a substrate by irradiating the substrate with light, comprising: a chamber for housing the substrate; a holding part for holding the substrate within the chamber; a first light source for irradiating the substrate held in the holding part with light; and a second light source different from the first light source for irradiating the substrate held in the holding part with light, wherein at least a portion of the irradiation area from the first light source to the substrate overlaps with the irradiation area from the second light source to the substrate, and a common power supply circuit for supplying power to the first light source and the second light source. The first light source is an LED lamp, and the second light source emits light with higher directivity than the first light source, and the second light source is a vertical-cavity surface-emitting laser. It is characterized by the following:

[0015] Furthermore, claims 2 The invention is claimed 1 The heat treatment apparatus according to the invention is characterized in that the power supply circuit includes a PWM control circuit.

[0016] Furthermore, claims 3 The invention is claimed 1 The heat treatment apparatus according to the invention is characterized in that the power supply circuit includes a constant current circuit.

[0017] Furthermore, claims 4 The invention is claimed 1 The heat treatment apparatus according to the invention is characterized in that the irradiation area of ​​the second light source is the peripheral edge of the substrate.

[0018] Furthermore, claims 5 The invention is claimed 1 The heat treatment apparatus according to the invention is further characterized by comprising a flash lamp that irradiates the substrate held in the holding part with flash light. Furthermore, the invention of claim 6 is a heat treatment apparatus for heating a substrate by irradiating the substrate with light, comprising: a chamber for housing the substrate; a holding part for holding the substrate within the chamber; a first light source for irradiating the substrate held in the holding part with light; and a second light source different from the first light source for irradiating the substrate held in the holding part with light, wherein at least a portion of the irradiation area from which light is irradiated to the substrate by the first light source overlaps with the irradiation area from which light is irradiated to the substrate by the second light source, and a common power supply circuit for supplying power to the first light source and the second light source, wherein the power supply circuit comprises a DC boost circuit that outputs DC, a shunt resistor for measuring the DC current value output from the DC boost circuit, a PWM control circuit that changes the duty cycle of a pulse wave based on the current value measured by the shunt resistor, and a MOSFET whose opening and closing is controlled by the PWM control circuit. [Effects of the Invention]

[0019] Claims 1 to Claims 6According to the invention, at least a part of the irradiation region for irradiating the substrate with light from the first light source overlaps with the irradiation region for irradiating the substrate with light from the second light source, and a common power supply circuit for supplying power to the first light source and the second light source is provided. Therefore, a single power supply circuit supplies power to different types of first light source and second light source for batch control, and the enlargement and high cost of the power supply circuit can be suppressed.

Brief Description of Drawings

[0020] [Figure 1] It is a longitudinal sectional view showing the configuration of the heat treatment apparatus according to the present invention. [Figure 2] It is a perspective view showing the overall appearance of the holding part. [Figure 3] It is a plan view of the susceptor. [Figure 4] It is a sectional view of the susceptor. [Figure 5] It is a plan view of the transfer mechanism. [Figure 6] It is a side view of the transfer mechanism. [Figure 7] It is a plan view showing the arrangement of a plurality of LED lamps and a plurality of VCSELs. [Figure 8] It is a diagram schematically showing light irradiation from the LED lamp and the VCSEL to the semiconductor wafer. [Figure 9] It is a diagram showing the power supply circuit for supplying power to the LED lamp and the VCSEL. [Figure 10] It is a diagram showing the power supply circuit of the second embodiment. [Figure 11] It is a diagram showing the arrangement of the LED lamp and the VCSEL of the third embodiment.

Embodiments for Carrying Out the Invention

[0021] Embodiments of the present invention will be described in detail below with reference to the drawings. In the following, expressions indicating relative or absolute positional relationships (e.g., "in one direction," "along one direction," "parallel," "orthogonal," "center," "concentric," "coaxial," etc.) shall, unless otherwise specified, not only strictly represent the positional relationship but also represent a state in which there is a relative displacement in terms of angle or distance within a tolerance or a range in which a similar level of function can be obtained. Similarly, expressions indicating equality (e.g., "identical," "equal," "homogeneous," etc.) shall, unless otherwise specified, not only represent a state in which there is a quantitatively strictly equal state but also represent a state in which there is a difference in which a tolerance or a similar level of function can be obtained. Furthermore, expressions indicating shape (e.g., "circular," "square," "cylindrical," etc.) shall, unless otherwise specified, not only strictly represent the geometrically precise shape but also represent a shape within a range in which a similar level of effect can be obtained, and may have, for example, irregularities or chamfers. Additionally, expressions such as "equipped," "possessing," "containing," "having," etc., for a component are not exclusive expressions that exclude the existence of other components. Furthermore, the expression "at least one of A, B, and C" includes "A only," "B only," "C only," "any two of A, B, and C," and "all of A, B, and C."

[0022] <First Embodiment> Figure 1 is a longitudinal cross-sectional view showing the configuration of the heat treatment apparatus 1 according to the present invention. The heat treatment apparatus 1 in Figure 1 is a flash lamp annealing apparatus that heats a disc-shaped semiconductor wafer W, which is used as a substrate, by flashing light onto the wafer. The size of the semiconductor wafer W to be processed is not particularly limited, but for example, it may be φ300 mm or φ450 mm. Note that in Figure 1 and subsequent figures, the dimensions and number of parts are exaggerated or simplified as necessary for ease of understanding.

[0023] The heat treatment apparatus 1 comprises a chamber 6 for housing a semiconductor wafer W, a flash heating unit 5 incorporating multiple flash lamps FL, and an auxiliary heating unit 4 equipped with multiple LED (light-emitting diode) lamps 47 and multiple VCSELs (vertical cavity surface-emitting lasers) 45. The flash heating unit 5 is located on the upper side of the chamber 6, while the auxiliary heating unit 4 is located on the lower side. The heat treatment apparatus 1 also includes a holding unit 7 inside the chamber 6 for holding the semiconductor wafer W in a horizontal position, and a transfer mechanism 10 for transferring 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 the operating mechanisms provided in the auxiliary heating unit 4, the flash heating unit 5, and the chamber 6 to perform heat treatment on the semiconductor wafer W.

[0024] Chamber 6 is constructed by mounting quartz chamber windows on the top and bottom of a cylindrical chamber side section 61. The chamber side section 61 has a roughly cylindrical shape with openings at the top and bottom. The upper opening is closed by an upper chamber window 63, and the lower opening is closed by a lower chamber window 64. The upper chamber window 63, which forms the ceiling of chamber 6, is a disc-shaped member made of quartz and functions as a quartz window that transmits flash light emitted from the flash heating section 5 into chamber 6. Similarly, the lower chamber window 64, which forms the floor of chamber 6, is also a disc-shaped member made of quartz and functions as a quartz window that transmits light from the auxiliary heating section 4 into chamber 6.

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

[0026] By attaching the reflective rings 68 and 69 to the chamber side portion 61, a recess 62 is formed on the inner wall surface of the chamber 6. Specifically, the recess 62 is formed by the central portion of the inner wall surface of the chamber side portion 61 where the reflective rings 68 and 69 are not attached, the lower end surface of the reflective ring 68, and the upper end surface of the reflective ring 69. The recess 62 is formed in an annular shape along the horizontal direction on the inner wall surface of the chamber 6 and surrounds the holding portion 7 that holds the semiconductor wafer W. The chamber side portion 61 and the reflective rings 68 and 69 are made of a metal material (for example, stainless steel) with excellent strength and heat resistance.

[0027] Furthermore, a transport opening (furnace opening) 66 is provided on the side portion 61 of the chamber for loading and unloading semiconductor wafers W into and out of the chamber 6. The transport opening 66 can be opened and closed by a gate valve 185. The transport opening 66 is connected in communication with the outer surface of the recess 62. Therefore, when the gate valve 185 is open, semiconductor wafers W can be loaded into the heat treatment space 65 from the transport opening 66 through the recess 62 and unloaded from the heat treatment space 65. When the gate valve 185 closes the transport opening 66, the heat treatment space 65 inside the chamber 6 becomes a sealed space.

[0028] Furthermore, a through-hole 61a is drilled in the side portion 61 of the chamber. A radiation thermometer 20 is attached to the portion of the outer wall surface of the side portion 61 of the chamber where the through-hole 61a is provided. The through-hole 61a is a cylindrical hole for guiding infrared light emitted from the lower surface of the semiconductor wafer W held by the susceptor 74 (described later) to the radiation thermometer 20. The through-hole 61a is provided at an inclination with respect to the horizontal direction such that its axis in the direction of penetration intersects with the main surface of the semiconductor wafer W held by the susceptor 74. Therefore, the radiation thermometer 20 is provided diagonally below the susceptor 74. A transparent window 21 made of barium fluoride material that transmits infrared light in the wavelength range measurable by the radiation thermometer 20 is attached to the end of the through-hole 61a facing the heat treatment space 65.

[0029] Furthermore, a gas supply hole 81 for supplying a processing gas to the heat treatment space 65 is formed in the upper part of the inner wall of the chamber 6. The gas supply hole 81 is formed in a position above the recess 62 and may be provided in the reflecting 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. A valve 84 is also interposed in the path of the gas supply pipe 83. When the valve 84 is opened, processing gas is supplied from the processing gas supply source 85 to the buffer space 82. The processing gas that flows into the buffer space 82 spreads out within the buffer space 82, which has less fluid resistance than the gas supply hole 81, and is supplied from the gas supply hole 81 into the heat treatment space 65. As the processing gas, for example, an inert gas such as nitrogen (N2), or a reactive gas such as hydrogen (H2), ammonia (NH3), or a mixed gas of these can be used (in this embodiment, nitrogen gas).

[0030] On the other hand, a gas exhaust port 86 for exhausting gas from the heat treatment space 65 is formed in the lower part of the inner wall of the chamber 6. The gas exhaust port 86 is formed in a position below the recess 62 and may be provided in the reflecting ring 69. The gas exhaust port 86 is connected to a gas exhaust pipe 88 via a buffer space 87 formed in an annular shape inside the side wall of the chamber 6. The gas exhaust pipe 88 is connected to the exhaust section 190. A valve 89 is interposed in the path of the gas exhaust pipe 88. When the valve 89 is opened, the gas from the heat treatment space 65 is discharged from the gas exhaust port 86 through the buffer space 87 to the gas exhaust pipe 88. Note that there may be multiple gas supply holes 81 and gas exhaust holes 86 along the circumferential direction of the chamber 6, or they may be slit-shaped. Also, the processing gas supply source 85 and the exhaust section 190 may be mechanisms provided in the heat treatment apparatus 1, or they may be utilities of the factory where the heat treatment apparatus 1 is installed.

[0031] 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 susceptor 74. The base ring 71, the connecting part 72, and the susceptor 74 are all made of quartz. In other words, the entire holding part 7 is made of quartz.

[0032] The base ring 71 is a quartz material with an arc shape, partially missing from its annular shape. This missing portion is provided to prevent interference between the transfer arm 11 of the transfer mechanism 10 (described later) and the base ring 71. The base ring 71 is supported by the wall surface of the chamber 6 by being placed on the bottom surface of the recess 62 (see Figure 1). Multiple connecting parts 72 (four in this embodiment) are erected on the upper surface of the base ring 71 along the circumferential direction of its annular shape. The connecting parts 72 are also made of quartz material and are fixed to the base ring 71 by welding.

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

[0034] A guide ring 76 is installed on the upper peripheral edge of the retaining plate 75. The guide ring 76 is an annular member having an inner diameter larger than the diameter of the semiconductor wafer W. For example, if the diameter of the semiconductor wafer W is φ300 mm, the inner diameter of the guide ring 76 is φ320 mm. The inner circumference of the guide ring 76 is tapered so as to widen upward from the retaining plate 75. The guide ring 76 is made of quartz, the same material as the retaining plate 75. The guide ring 76 may be welded to the upper surface of the retaining plate 75, or it may 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 may be manufactured as a single integrated member.

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

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

[0037] The semiconductor wafer W, once loaded into the chamber 6, is placed and held in a horizontal position on the susceptor 74 of the holding unit 7 mounted on 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 by the susceptor 74. More precisely, the upper ends of the 12 substrate support pins 77 contact the lower surface of the semiconductor wafer W to support it. Since the height of the 12 substrate support pins 77 (the distance from the upper end of the substrate support pins 77 to the holding surface 75a of the holding plate 75) is uniform, the semiconductor wafer W can be supported in a horizontal position by the 12 substrate support pins 77.

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

[0039] Furthermore, as shown in Figures 2 and 3, the holding plate 75 of the susceptor 74 has an opening 78 that penetrates vertically. The opening 78 is provided for the radiation thermometer 20 to receive synchrotron radiation (infrared light) emitted from the lower surface of the semiconductor wafer W. That is, the radiation thermometer 20 measures the temperature of the semiconductor wafer W by receiving light emitted from the lower surface of the semiconductor wafer W through the opening 78 and a transparent window 21 fitted in the through hole 61a of the chamber side portion 61. In addition, the holding plate 75 of the susceptor 74 has four through holes 79 through which the lift pins 12 of the transfer mechanism 10, which will be described later, pass the semiconductor wafer W.

[0040] Figure 5 is a plan view of the transfer mechanism 10. Figure 6 is a side view of the transfer mechanism 10. The transfer mechanism 10 comprises two transfer arms 11. The transfer arms 11 are shaped like arcs that generally follow the annular recess 62. Two lift pins 12 are erected on each transfer arm 11. The transfer arms 11 and lift pins 12 are made of quartz. Each transfer arm 11 is rotatable by a horizontal movement mechanism 13. The horizontal movement mechanism 13 moves the pair of transfer arms 11 horizontally between a transfer operation position (solid line position in Figure 5) where the semiconductor wafer W is transferred to the holding part 7 and a retracted position (dotted line position in Figure 5) where the semiconductor wafer W held by the holding part 7 does not overlap in a plan view. The horizontal movement mechanism 13 may consist of individual motors that rotate each transfer arm 11, or it may consist of a linkage mechanism that uses a single motor to rotate a pair of transfer arms 11 in conjunction with each other.

[0041] Furthermore, the pair of transfer arms 11 are moved up and down together with the horizontal movement mechanism 13 by the lifting mechanism 14. When the lifting mechanism 14 raises the pair of transfer arms 11 to the transfer operation position, a total of four lift pins 12 pass through through holes 79 (see Figures 2 and 3) drilled in the susceptor 74, and the upper ends of the lift pins 12 protrude from the upper surface of the susceptor 74. On the other hand, when the lifting mechanism 14 lowers the pair of transfer arms 11 to the transfer operation position and removes the lift pins 12 from the through holes 79, and the horizontal movement mechanism 13 moves the pair of transfer arms 11 to open, each transfer arm 11 moves to a retracted position. The retracted position of the pair of transfer arms 11 is directly above the base ring 71 of the holding part 7. Since the base ring 71 is placed on the bottom surface of the recess 62, the retracted position of the transfer arms 11 is inside the recess 62. Furthermore, an exhaust mechanism (not shown) is also provided near the area where the drive unit (horizontal movement mechanism 13 and lifting mechanism 14) of the transfer mechanism 10 is located, so that the atmosphere around the drive unit of the transfer mechanism 10 is discharged to the outside of the chamber 6.

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

[0043] Each of the multiple flash lamps FL is a rod-shaped lamp with a long cylindrical shape, and they are arranged in a planar manner such that their longitudinal 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 part 7. Therefore, the plane formed by the arrangement of the flash lamps FL is also a horizontal plane. The area in which the multiple flash lamps FL are arranged is larger than the planar size of the semiconductor wafer W.

[0044] A xenon flash lamp FL comprises a cylindrical glass tube (discharge tube) containing xenon gas, with an anode and cathode connected to capacitors at both ends, and a trigger electrode attached to the outer surface of the glass tube. Since xenon gas is an electrically insulating material, electricity does not flow through the glass tube under normal conditions, even if charge is stored in the capacitor. However, when a high voltage is applied to the trigger electrode to break the insulation, the electricity stored in the capacitor flows instantaneously through the glass tube, and light is emitted due to the excitation of xenon atoms or molecules at that time. In such a xenon flash lamp FL, the electrostatic energy previously stored in the capacitor is converted into extremely short light pulses of 0.1 milliseconds to 100 milliseconds, giving it 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, a flash lamp FL is a pulse-emitting lamp that emits light instantaneously in an extremely short time of less than one second. Furthermore, the illumination time of the flash lamp FL can be adjusted by the coil constant of the lamp power supply that provides power to the flash lamp FL.

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

[0046] The auxiliary heating unit 4, located below the chamber 6, incorporates multiple LED lamps (first light source) 47 and multiple VCSELs (second light source) 45 inside the housing 41. In other words, the auxiliary heating unit 4 of this embodiment is equipped with two different light sources. The auxiliary heating unit 4 is an auxiliary light source that heats the semiconductor wafer W by irradiating light from below the chamber 6 through the lower chamber window 64 into the heat treatment space 65 using multiple LED lamps 47 and multiple VCSELs 45.

[0047] Figure 7 is a plan view showing the arrangement of multiple LED lamps 47 and multiple VCSELs 45. While the auxiliary heating unit 4 has numerous LED lamps 47 and VCSELs 45, the number is simplified in Figure 7 for illustrative purposes. Unlike conventional halogen lamps, which are rod-shaped lamps, each LED lamp 47 and each VCSEL 45 is a point light source.

[0048] Multiple LED lamps 47 are arranged at a uniform density in a circular area. The size of the circular area where the multiple LED lamps 47 are arranged is approximately the same as the semiconductor wafer W. Each LED lamp 47 contains a light-emitting diode. A light-emitting diode is a type of diode that emits light through the electroluminescence effect when a voltage is applied in the forward direction.

[0049] Multiple VCSELs 45 are arranged around a circular area where multiple LED lamps 47 are located. In other words, in the first embodiment, multiple LED lamps 47 are arranged in the center of the auxiliary heating unit 4, and multiple VCSELs 45 are arranged around the periphery. A VCSEL (Vertical Cavity Surface Emitting Laser) 45 is a type of semiconductor laser that emits light perpendicular to the surface of the semiconductor substrate on which the element is attached. The VCSEL 45 is capable of emitting light of relatively high intensity. In addition, the VCSEL 45 is capable of irradiating light with higher directionality compared to the LED lamps 47. In other words, the LED lamps 47 have a wider light irradiation range than the VCSEL 45. The VCSEL 45 in the first embodiment irradiates light with a wavelength of 940 nm. Both the LED lamps 47 and the VCSEL 45 are continuous-lighting lamps that emit light continuously for at least 1 second or more.

[0050] Figure 8 schematically shows the light irradiation of the semiconductor wafer W from the LED lamps 47 and VCSEL 45. The multiple LED lamps 47 are arranged horizontally in a circular area. That is, the plane formed by the arrangement of the multiple LED lamps 47 is a horizontal plane. The circular area where the multiple LED lamps 47 are arranged has the same size as the semiconductor wafer W and is positioned to face the lower surface of the semiconductor wafer W held by the holding part 7. Light is emitted from each LED lamp 47 at a relatively wide angle, and as a result, the multiple LED lamps 47 arranged in the circular area facing the lower surface of the semiconductor wafer W irradiate the entire lower surface of the semiconductor wafer W with light approximately evenly.

[0051] On the other hand, since the multiple VCSELs 45 are arranged around the circular area where the multiple LED lamps 47 are positioned, they are located on the outside of the semiconductor wafer W held by the holding portion 7. For this reason, the multiple VCSELs 45 are installed at an angle so that their irradiation direction faces the lower surface of the semiconductor wafer W. Light is irradiated from each VCSEL 45, which emits relatively directional light, onto the lower peripheral edge of the semiconductor wafer W.

[0052] When light is irradiated only from multiple LED lamps 47, the temperature of the peripheral part of the semiconductor wafer W, where heat dissipation is likely to occur, tends to be lower than the temperature of the central part. In the first embodiment, in addition to irradiating the entire lower surface of the semiconductor wafer W with light from multiple LED lamps 47, light is also irradiated to the lower peripheral part of the semiconductor wafer W with light from multiple VCSELs 45. The irradiation area of ​​the multiple LED lamps 47 is the entire lower surface of the semiconductor wafer W, while the irradiation area of ​​the multiple VCSELs 45 is the lower peripheral part of the semiconductor wafer W. In other words, the lower peripheral part of the semiconductor wafer W is irradiated with light from both the LED lamps 47 and the VCSELs 45. As a result, the peripheral part of the semiconductor wafer W, where temperature drops are likely to occur with only LED lamps 47, can be strongly heated by irradiating the peripheral part with highly directional light from the VCSELs 45, and the in-plane temperature distribution of the semiconductor wafer W can be made uniform.

[0053] Figure 9 shows a power supply circuit that supplies power to the LED lamp 47 and the VCSEL 45. As described above, at least a portion of the irradiation area (the wafer periphery in the first embodiment) from the LED lamp 47 to the semiconductor wafer W overlaps with the irradiation area from the VCSEL 45 to the semiconductor wafer W. Thus, a common power supply circuit 90 is provided for the LED lamp 47 and the VCSEL 45 whose irradiation areas overlap, specifically the LED lamp 47 and the VCSEL 45 that irradiate the periphery of the semiconductor wafer W.

[0054] The power supply circuit 90 includes a DC boost circuit 91, a PWM control circuit 92, a shunt resistor 93, and a MOSFET 94, etc. The DC boost circuit 91 is a circuit that converts the voltage of the current (DC) from the current source. The DC boost circuit 91 outputs DC at a voltage level higher than the input voltage. The DC boost circuit 91 of the first embodiment outputs a DC current of, for example, 50V to 60V.

[0055] The PWM (Pulse Width Modulation) control circuit 92 controls the on / off state of the MOSFET 94 by changing the duty cycle of the pulse wave (the ratio of the pulse width of the on-pulse to the pulse width of the off-pulse). Specifically, the PWM control circuit 92 outputs a pulse signal to the gate of the MOSFET 94 that repeatedly switches on and off. While the PWM control circuit 92 outputs an on-pulse, the MOSFET 94 is in the on state. While the PWM control circuit 92 outputs an off-pulse, the MOSFET 94 is in the off state. Therefore, by outputting a pulse signal from the PWM control circuit 92 to the gate of the MOSFET 94, the MOSFET 94 repeatedly switches on and off.

[0056] The shunt resistor 93 is a resistor used to measure the DC current value output from the DC boost circuit. The PWM control circuit 92 changes the duty cycle of the pulse wave based on the current value measured by the shunt resistor 93.

[0057] The MOSFET (Metal Oxide Semiconductor Field Effect Transistor) 94 is a MOS-structured field-effect transistor. In this embodiment, the MOSFET 94 functions as a switching element for supplying power to the LED lamp 47 and the VCSEL 45. As described above, the switching operation of the MOSFET 94 is controlled by a pulse signal output from the PWM control circuit 92.

[0058] As shown in Figure 9, multiple LED lamps 47 and multiple VCSELs 45 are connected in parallel to the power supply circuit 90. The power supply circuit 90 is connected to the LED lamps 47 and VCSELs 45 whose illumination areas overlap, that is, the LED lamps 47 and VCSELs 45 that illuminate the peripheral area of ​​the semiconductor wafer W. Therefore, power can be supplied from a common power supply circuit 90 to both the LED lamps 47 and VCSELs 45 whose illumination areas overlap.

[0059] Furthermore, multiple LED lamps 47 are connected in series, as are multiple VCSELs 45. The DC boost circuit 91 of the first embodiment outputs a DC voltage of 50V to 60V, and the voltage drop across a single LED lamp 47 and VCSEL 45 is only a few volts. Therefore, it is preferable to connect 7 to 8 LED lamps 47 and VCSELs 45 in series to the power supply circuit 90 of the first embodiment.

[0060] The power supply circuit 90 controls the outputs of the LED lamp 47 and VCSEL 45 connected to it by controlling the on / off state of the MOSFET 94 via a PWM control circuit 92. If the PWM control circuit 92 increases the duty cycle of the pulse wave, the MOSFET 94 will be open for a longer time, resulting in higher outputs for the LED lamp 47 and VCSEL 45. Conversely, if the PWM control circuit 92 decreases the duty cycle of the pulse wave, the MOSFET 94 will be open for a shorter time, resulting in lower outputs for the LED lamp 47 and VCSEL 45.

[0061] Since the LED lamps 47 and VCSEL 45, whose illumination areas overlap, are connected in parallel to the power supply circuit 90, the outputs of the LED lamps 47 and VCSEL 45 fluctuate proportionally. For example, when the output of the LED lamp 47 increases by 20%, the output of the VCSEL 45 also increases by 20%. In other words, the power supply circuit 90 causes the outputs of the LED lamps 47 and VCSEL 45, whose illumination areas overlap, to fluctuate in the same way.

[0062] The control unit 3 controls the various operating mechanisms provided in the heat treatment apparatus 1. The hardware configuration of the control unit 3 is similar to that of a general computer. Specifically, the control unit 3 includes a CPU, which is a circuit that performs various calculations; a ROM, which is a read-only memory that stores basic programs; a RAM, which is a read-write memory that stores various information; and a storage unit (e.g., a magnetic disk or SSD) that stores control software and data. Processing in the heat treatment apparatus 1 proceeds when the CPU of the control unit 3 executes a predetermined processing program. The control unit 3 also controls the power supply circuit 90 to adjust the output of the LED lamp 47 and the VCSEL 45.

[0063] In addition to the above configuration, the heat treatment apparatus 1 is equipped with various cooling structures to prevent excessive temperature rise in the auxiliary heating section 4, flash heating section 5, and chamber 6 due to thermal energy generated from the LED lamp 47, VCSEL 45, and flash lamp FL during the heat treatment of the semiconductor wafer W. For example, water cooling pipes (not shown) are provided in the wall of the chamber 6. Furthermore, the auxiliary heating section 4 and flash heating section 5 are air-cooled structures that dissipate heat by forming a gas flow inside. In addition, air is supplied to the gap between the upper chamber window 63 and the lamp light emission window 53 to cool the flash heating section 5 and the upper chamber window 63.

[0064] Next, the processing operation in the heat treatment apparatus 1 will be described. Here, a typical heat treatment operation for a standard semiconductor wafer (product wafer) W that will become a product will be described. The semiconductor wafer W to be processed is a silicon (Si) semiconductor substrate into which impurities have been implanted by ion implantation as a front-end process. The activation of these impurities is performed by the annealing process carried out by the heat treatment apparatus 1. The processing procedure for the semiconductor wafer W described below proceeds as the control unit 3 controls each operating mechanism of the heat treatment apparatus 1.

[0065] First, prior to processing the semiconductor wafer W, the supply valve 84 is opened and the exhaust valve 89 is opened, initiating the supply and exhaust of air into the chamber 6. When valve 84 is opened, nitrogen gas is supplied to the heat treatment space 65 from the gas supply hole 81. When valve 89 is opened, the gas inside the chamber 6 is exhausted from the gas exhaust hole 86. As a result, the nitrogen gas supplied from the top of the heat treatment space 65 inside the chamber 6 flows downward and is exhausted from the bottom of the heat treatment space 65.

[0066] Next, the gate valve 185 opens, the transport opening 66 is opened, and the semiconductor wafer W to be processed is transported through the transport opening 66 by a transport robot outside the apparatus into the heat treatment space 65 inside the chamber 6. At this time, there is a risk that the atmosphere outside the apparatus may be drawn in as the semiconductor wafer W is transported in, but since nitrogen gas is continuously supplied to the chamber 6, the nitrogen gas flows out from the transport opening 66, minimizing the entrainment of such external atmosphere.

[0067] The semiconductor wafer W, loaded by the transport robot, moves forward to a position directly above the holding section 7 and stops. Then, the pair of transfer arms 11 of the transfer mechanism 10 move horizontally from the retracted position to the transfer operation position and rise, causing the lift pin 12 to protrude from the upper surface of the holding plate 75 of the susceptor 74 through the through hole 79 and receive the semiconductor wafer W. At this time, the lift pin 12 rises above the upper end of the substrate support pin 77.

[0068] After the semiconductor wafer W is placed on the lift pin 12, the transport robot exits the heat treatment space 65, and the transport opening 66 is closed by the gate valve 185. Then, as the pair of transfer arms 11 descend, the semiconductor wafer W is transferred from the transfer mechanism 10 to the susceptor 74 of the holding section 7 and held from below in a horizontal position. The semiconductor wafer W is supported by a plurality of substrate support pins 77 erected on the holding plate 75 and held by the susceptor 74. The semiconductor wafer W is also held in the holding section 7 with the patterned surface and impurities injected facing upwards. A predetermined gap is formed between the back surface (the main surface opposite to the front surface) of the semiconductor wafer W, which is supported by the plurality of substrate support pins 77, and the holding surface 75a of the holding plate 75. The pair of transfer arms 11, which have descended to below the susceptor 74, are retracted to a retracted position, i.e., inside the recess 62, by the horizontal movement mechanism 13.

[0069] After the semiconductor wafer W is held horizontally from below by the susceptor 74 of the holding part 7 made of silica, light is irradiated from multiple LED lamps 47 and multiple VCSELs 45 of the auxiliary heating part 4 to start preheating (assisted heating). The light emitted from the auxiliary heating part 4 passes through the lower chamber window 64 and susceptor 74 made of silica and irradiates the lower surface of the semiconductor wafer W. The semiconductor wafer W is preheated and its temperature rises due to the light irradiation from the auxiliary heating part 4. The transfer arm 11 of the transfer mechanism 10 is retracted inside the recess 62 and does not interfere with heating by the auxiliary heating part 4.

[0070] The temperature of the semiconductor wafer W, which is heated by light irradiation from the auxiliary heating unit 4, is measured by a radiation thermometer 20. The measured temperature of the semiconductor wafer W is transmitted to the control unit 3. The control unit 3 monitors whether the temperature of the semiconductor wafer W, which is heated by light irradiation from the auxiliary heating unit 4, has reached a predetermined preheating temperature T1, and controls the power supply circuit 90 to adjust the output of the LED lamp 47 and VCSEL 45. That is, the control unit 3 feedback-controls the output of the LED lamp 47 and VCSEL 45 based on the measurement value from the radiation thermometer 20 so that the temperature of the semiconductor wafer W becomes the preheating temperature T1. The preheating temperature T1 is set to approximately 200°C to 800°C, preferably 350°C to 600°C (600°C in this embodiment), so that there is no risk of impurities added to the semiconductor wafer W diffusing due to heat.

[0071] After the semiconductor wafer W reaches the preheating temperature T1, the control unit 3 temporarily maintains the semiconductor wafer W at that preheating temperature T1. Specifically, when the temperature of the semiconductor wafer W, as measured by the radiation thermometer 20, reaches the preheating temperature T1, the control unit 3 adjusts the output of the LED lamp 47 and VCSEL 45 to maintain the temperature of the semiconductor wafer W at approximately the preheating temperature T1.

[0072] When the semiconductor wafer W reaches the preheating temperature T1 and a predetermined time has elapsed, the flash lamp FL of the flash heating unit 5 irradiates the surface of the semiconductor wafer W held by the susceptor 74 with flash light. At this time, a portion of the flash light emitted from the flash lamp FL goes directly into the chamber 6, and another portion is reflected by the reflector 52 before going into the chamber 6, and the semiconductor wafer W is flash-heated by the irradiation of these flash lights.

[0073] Flash heating is performed by irradiation with flash light (blink) from a flash lamp FL, which allows the surface temperature of the semiconductor wafer W to be raised in a short time. Specifically, the flash light irradiated from the flash lamp FL is an extremely short and strong flash with an irradiation time of about 0.1 milliseconds to 100 milliseconds, in which electrostatic energy previously stored in a capacitor is converted into an extremely short light pulse. The surface temperature of the semiconductor wafer W, which is flash-heated by irradiation with flash light from the flash lamp FL, instantly rises to a processing temperature T2 of 1000°C or more, and after the impurities injected into the semiconductor wafer W are activated, the surface temperature rapidly decreases. In this way, the heat treatment apparatus 1 can raise and lower the surface temperature of the semiconductor wafer W in an extremely short time, so that the impurities injected into the semiconductor wafer W can be activated while suppressing thermal diffusion of the impurities. Furthermore, since the time required for impurity activation is extremely short compared to the time required for thermal diffusion, activation can be completed even in a short time of about 0.1 milliseconds to 100 milliseconds, in which no diffusion occurs.

[0074] After the flash heating process is completed, the light irradiation from the auxiliary heating unit 4 is also stopped after a predetermined time has elapsed. This causes the semiconductor wafer W to rapidly cool down from the preheating temperature T1. The temperature of the semiconductor wafer W during the cooling process is measured by the radiation thermometer 20, and the measurement result is transmitted to the control unit 3. The control unit 3 monitors whether the temperature of the semiconductor wafer W has cooled down to a predetermined temperature based on the measurement result from the radiation thermometer 20. After the temperature of the semiconductor wafer W has cooled down to below the predetermined temperature, the pair of transfer arms 11 of the transfer mechanism 10 move horizontally again from the retracted position to the transfer operation position and rise, causing the lift pin 12 to protrude from the upper surface of the susceptor 74 and receive the heat-treated semiconductor wafer W from the susceptor 74. Subsequently, the transport opening 66, which had been closed by the gate valve 185, is opened, and the semiconductor wafer W placed on the lift pin 12 is transported out of the chamber 6 by a transport robot outside the device, completing the heat treatment of the semiconductor wafer W.

[0075] In the first embodiment, multiple VCSELs 45 are arranged around a plurality of LED lamps 47 arranged in a circular region. The LED lamps 47 illuminate the entire surface of the semiconductor wafer W, while the VCSELs 45, which emit relatively directional light, illuminate the peripheral portion of the semiconductor wafer W. This allows the peripheral portion of the semiconductor wafer W, which is prone to temperature drops during preheating, to be strongly heated by irradiating it with directional light from the VCSELs 45, thereby making the in-plane temperature distribution of the semiconductor wafer W uniform during preheating.

[0076] Furthermore, a common power supply circuit 90 is provided for multiple LED lamps 47 and multiple VCSELs 45 that irradiate the peripheral edge of the semiconductor wafer W. The power supply circuit 90 controls the output of the multiple LED lamps 47 and multiple VCSELs 45 whose irradiation areas overlap. Because a single power supply circuit 90 supplies power to two different types of light sources and controls them together, it is possible to suppress the increase in size and cost of the power supply circuit compared to providing a separate power supply circuit for each light source. In other words, by reducing the number of power supply circuits, space saving and cost reduction can be achieved.

[0077] Since multiple LED lamps 47 and multiple VCSELs 45 are controlled collectively by a common power supply circuit 90, their outputs are controlled in the same way. For example, it is not possible to control the output of the LED lamps 47 while increasing the output of the VCSELs 45. However, since the illumination areas of the multiple LED lamps 47 and multiple VCSELs 45 controlled collectively by the common power supply circuit 90 overlap, the inability to control them individually is not a problem.

[0078] <Second Embodiment> Next, a second embodiment of the present invention will be described. In the first embodiment, a PWM control circuit 92 and a MOSFET 94 were incorporated into the power supply circuit 90, and the output of the LED lamp 47 and VCSEL 45 was adjusted by changing the duty cycle of the pulse wave with the PWM control circuit 92. In the second embodiment, the power supply circuit is a constant current circuit, and a constant current is supplied to the LED lamp 47 and VCSEL 45.

[0079] Figure 10 shows the power supply circuit of the second embodiment. In the second embodiment, a constant current circuit 99 is provided as the power supply circuit. The constant current circuit 99 is a power supply circuit that supplies a constant current regardless of the load of the connected elements or the magnitude of the voltage across its terminals.

[0080] The configuration of the connection of the LED lamps 47 and VCSELs 45 to the constant current circuit 99 is the same as in the first embodiment. That is, multiple LED lamps 47 and multiple VCSELs 45 with overlapping illumination areas are connected in parallel to the constant current circuit 99. A common constant current circuit 99 is provided for the LED lamps 47 and VCSELs 45 with overlapping illumination areas, and power is supplied to both the LED lamps 47 and VCSELs 45 from this common constant current circuit 99. Multiple LED lamps 47 are connected in series, and multiple VCSELs 45 are also connected in series.

[0081] Even in the second embodiment, since a single constant current circuit 99 supplies power to two different types of light sources and controls them together, it is possible to suppress the increase in size and cost of the power supply circuit. However, in the second embodiment, since the constant current circuit 99 supplies a constant current to the LED lamp 47 and VCSEL 45, the outputs of the LED lamp 47 and VCSEL 45 are fixed. The configuration and processing operation of the second embodiment are the same as those of the first embodiment, except that a constant current circuit 99 is used as the power supply circuit.

[0082] <Third Embodiment> Next, a third embodiment of the present invention will be described. Figure 11 is a diagram showing the arrangement of LED lamps 47 and VCSELs 45 in the third embodiment. Figure 11 shows a plan view of the arrangement of LED lamps 47 and VCSELs 45 as seen from above. In Figure 11, the LED lamps 47 are shown in white outline, and the VCSELs 45 are shown with hatching.

[0083] In the first embodiment, multiple VCSELs 45 were arranged around multiple LED lamps 47, and light was irradiated from the VCSELs 45 onto the peripheral edge of the semiconductor wafer W. In the third embodiment, as shown in Figure 11, the LED lamps 47 and VCSELs 45 are arranged alternately in a grid pattern. The multiple LED lamps 47 and multiple VCSELs 45 as a whole form a checkerboard pattern.

[0084] In the arrangement shown in Figure 11, the illumination area of ​​the LED lamp 47, which emits light at a relatively wide angle, overlaps with the illumination area of ​​the adjacent VCSEL 45. The LED lamp 47 and VCSEL 45, whose illumination areas overlap, are connected to a common power supply circuit. Even in the third embodiment, since power is supplied to and controlled together by a single power supply circuit for two different types of light sources, it is possible to suppress the increase in size and cost of the power supply circuit.

[0085] <Fourth Embodiment> Next, a fourth embodiment of the present invention will be described. In the first to third embodiments, an LED lamp 47 and a VCSEL 45 were used as the light source for the auxiliary heating unit 4, but in the fourth embodiment, the light source for the auxiliary heating unit 4 is a halogen lamp. A halogen lamp is a filament-type light source that emits light by passing an electric current through a filament arranged inside a glass tube, causing the filament to become incandescent. Inside the glass tube, a gas is sealed in which a small amount of halogen element (iodine, bromine, etc.) has been introduced into an inert gas such as nitrogen or argon. By introducing halogen element, it is possible to set the temperature of the filament to a high temperature while suppressing filament breakage.

[0086] In the fourth embodiment, two types of halogen lamps with different specifications (e.g., lamp tube shape) are arranged in the auxiliary heating unit 4. At least a portion of the irradiation area of ​​one halogen lamp overlaps with the irradiation area of ​​the other halogen lamp. A common power supply circuit is provided for the two types of halogen lamps whose irradiation areas overlap. The power supply for the halogen lamps is an AC power supply. The power supply circuit adjusts the output of the two types of halogen lamps by PWM control or phase control.

[0087] As in the fourth embodiment, since a single power supply circuit supplies power to two different types of light sources and controls them together, it is possible to suppress the increase in size and cost of the power supply circuit.

[0088] <Variation> Although embodiments of the present invention have been described above, various modifications can be made to this invention without departing from its spirit. For example, in the first embodiment, multiple VCSELs 45 were arranged around multiple LED lamps 47, and in the third embodiment, the LED lamps 47 and VCSELs 45 were arranged alternately in a grid pattern, but the arrangement of the LED lamps 47 and VCSELs 45 is not limited to these. Since the VCSELs 45 emit relatively directional light, they may be arranged to irradiate areas of the semiconductor wafer W (so-called cold spots) where temperature drops are likely to occur during heating by multiple LED lamps 47 with light. Even in this case, by supplying power to the LED lamps 47 and VCSELs 45 with overlapping irradiation areas from a common power supply circuit, it is possible to suppress the enlargement and cost of the power supply circuit.

[0089] Furthermore, although the flash heating unit 5 is equipped with 30 flash lamps FL in the above embodiment, the number of flash lamps FL is not limited to this, and can be any number. Also, the flash lamps FL are not limited to xenon flash lamps, but may be krypton flash lamps. [Explanation of symbols]

[0090] 1 Heat treatment apparatus 3. Control Unit 4 Auxiliary heating section 5. Flash heating section 6 chambers 7 Holding part 10 Transfer mechanism 20 Radiation thermometer 45 VCSEL 47 LED lamps 65 Heat treatment space 74 Susceptors 90 Power supply circuit 91 DC Boost Circuit 92 PWM control circuit 94 MOSFET 99 Constant current circuit FL Flash Lamp W Semiconductor wafer

Claims

1. A heat treatment apparatus for heating a substrate by irradiating the substrate with light, A chamber for housing the circuit board, The chamber includes a holding portion for holding the substrate, A first light source that irradiates light onto the substrate held in the holding portion, A second light source, different from the first light source, irradiates light onto the substrate held in the holding portion, Equipped with, At least a portion of the irradiation area from which light is irradiated onto the substrate by the first light source overlaps with the irradiation area from which light is irradiated onto the substrate by the second light source. A common power supply circuit is provided to supply power to the first light source and the second light source, The first light source is an LED lamp, The second light source emits light with higher directivity than the first light source, The heat treatment apparatus is characterized in that the second light source is a vertical-cavity surface-emitting laser.

2. In the heat treatment apparatus according to claim 1, The heat treatment apparatus is characterized in that the power supply circuit includes a PWM control circuit.

3. In the heat treatment apparatus according to claim 1, The heat treatment apparatus is characterized in that the power supply circuit includes a constant current circuit.

4. In the heat treatment apparatus according to claim 1, A heat treatment apparatus characterized in that the irradiation area of ​​the second light source is the peripheral edge of the substrate.

5. In the heat treatment apparatus according to claim 1, A heat treatment apparatus further comprising a flash lamp for irradiating the substrate held in the holding portion with flash light.

6. A heat treatment apparatus for heating a substrate by irradiating the substrate with light, A chamber for housing the circuit board, The chamber includes a holding portion for holding the substrate, A first light source that irradiates light onto the substrate held in the holding portion, A second light source, different from the first light source, irradiates light onto the substrate held in the holding portion, Equipped with, At least a portion of the irradiation area from which light is irradiated onto the substrate by the first light source overlaps with the irradiation area from which light is irradiated onto the substrate by the second light source. A common power supply circuit is provided to supply power to the first light source and the second light source, The heat treatment apparatus is characterized in that the power supply circuit comprises a DC boost circuit that outputs DC, a shunt resistor that measures the DC current value output from the DC boost circuit, a PWM control circuit that changes the duty cycle of a pulse wave based on the current value measured by the shunt resistor, and a MOSFET whose switching is controlled by the PWM control circuit.

Images