Susceptors and heat treatment equipment

Abstract

The present invention provides a susceptor that allows for easy replacement of substrate support pins, and a heat treatment apparatus equipped with the susceptor. [Solution] Multiple screw holes of different diameters are formed in the susceptor's holding plate 75 in a concentric pattern. The substrate support pin 90 is attached by screwing the threaded portion 92 of the substrate support pin 90 into the screw holes from below the holding plate 75. When the entire threaded portion 92 is screwed into the screw hole, the pin portion 91 of the substrate support pin 90 protrudes from the upper surface of the holding plate 75. The semiconductor wafer is supported by the pin portion 91 protruding from the holding plate 75 and subjected to heat treatment. Since the substrate support pin 90 is detachably attached to the holding plate 75 by screwing, the substrate support pin 90 can be easily replaced.

Description

[Technical Field]

[0001] The present invention relates to a susceptor for supporting a substrate heated by light irradiation and a heat treatment apparatus equipped with the susceptor. 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, and substrates for solar cells. [Background Art]

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

[0003] The radiation spectral distribution of a xenon flash lamp ranges from the ultraviolet region to the near-infrared region, has a shorter wavelength than that of a conventional halogen lamp, and substantially matches the fundamental absorption band of silicon semiconductor wafers. Therefore, when a semiconductor wafer is irradiated with flash light from a xenon flash lamp, there is little transmitted light, and the temperature of the semiconductor wafer can be raised rapidly. It has also been found that, in the case of flash light irradiation 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 extremely short-time heating, for example, typically activation of impurities implanted into a semiconductor wafer. If the surface of a semiconductor wafer implanted with impurities by ion implantation is irradiated with flash light from a flash lamp, the temperature of the surface of the semiconductor wafer can be raised to the activation temperature for an extremely short time, and only impurity activation can be performed without deep diffusion of impurities.

[0005] In heat treatment equipment using a flash lamp, a semiconductor wafer is typically supported by multiple substrate support pins erected on a susceptor, and flash light is irradiated from the flash lamp. Because the flash lamp instantaneously irradiates the surface of the semiconductor wafer with flash light of extremely high energy, the surface temperature of the semiconductor wafer rises rapidly in an instant, while the temperature of the back surface does not rise as much. As a result, rapid thermal expansion occurs only on the surface of the semiconductor wafer, causing the semiconductor wafer to deform and warp with its surface convex. Consequently, especially when the energy of the flash light is high, stress concentration occurs on the back surface of the semiconductor wafer, which can cause the semiconductor wafer to crack.

[0006] Therefore, Patent Document 1 proposes a technique for preventing semiconductor wafer cracking during flash light irradiation by placing substrate support pins at an optimal position according to the pulse width of the flash light. In the technique disclosed in Patent Document 1, the shorter the pulse width of the irradiated flash light, the larger the diameter of the circle on which the multiple substrate support pins are arranged can prevent semiconductor wafer cracking. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2021-190552 [Overview of the project] [Problems that the invention aims to solve]

[0008] The pulse width of the flash light varies depending on the purpose and content of the flash lamp annealing process. Therefore, conventionally, when changing the flash lamp annealing process, the pulse width of the flash light also had to be changed, requiring the replacement of the entire susceptor, including multiple substrate support pins, each time to prevent cracking. In particular, when changing to a flash light pulse width that had not been used previously, a new susceptor had to be designed and manufactured, which required a considerable amount of time.

[0009] Furthermore, if contamination, damage, or wear occurred to the substrate support pins that come into direct contact with the semiconductor wafer, the entire susceptor had to be replaced.

[0010] The present invention has been made in view of the above problems, and aims to provide a susceptor that allows for easy replacement of substrate support pins, and a heat treatment apparatus equipped with the susceptor. [Means for solving the problem]

[0011] To solve the above problems, a first aspect of the present invention provides a susceptor for supporting a substrate heated by light irradiation, comprising a flat retaining plate made of quartz, and a plurality of substrate support pins provided on the retaining plate for supporting the substrate, wherein a plurality of screw holes are formed in the retaining plate, and each of the plurality of substrate support pins has a threaded portion formed with a screw thread that screws into the screw holes, and the plurality of substrate support pins are detachably provided in some of the screw holes.

[0012] Furthermore, in the second embodiment, the susceptor according to the first embodiment is formed such that the plurality of screw holes are arranged in a concentric pattern with different diameters.

[0013] Furthermore, in a third embodiment, the susceptor according to the second embodiment is provided in some of the screw holes formed along a circumference of a single diameter, wherein the plurality of substrate support pins are provided in some of the screw holes formed along a circumference of a single diameter.

[0014] Furthermore, in the fourth embodiment, the susceptor according to the second embodiment, the plurality of substrate support pins are provided in some of the screw holes formed along the circumferences of two or more different diameters.

[0015] Furthermore, the fifth embodiment is a susceptor according to any of the first to fourth embodiments, wherein each of the plurality of substrate support pins is provided with a pin portion that contacts the substrate on the upper side of the threaded portion and a screw-fastening portion having a larger planar size than the threaded portion on the lower side of the threaded portion, and each of the plurality of substrate support pins supports the substrate by the pin portion when the threaded portion is screwed into the screw hole.

[0016] Furthermore, in the sixth embodiment, in the susceptor according to the fifth embodiment, each of the plurality of substrate support pins is made of quartz.

[0017] Furthermore, the seventh embodiment is a susceptor according to any of the first to fourth embodiments, wherein each of the plurality of substrate support pins is provided with a cylindrical through portion having a smaller diameter than the threaded portion on the upper side of the threaded portion, and further provided with a pin portion that contacts the substrate on the upper side of the through portion, and each of the plurality of substrate support pins supports the substrate by the pin portion with the through portion loosely passing through the threaded hole.

[0018] Furthermore, in the eighth embodiment, in the susceptor according to the seventh embodiment, each of the plurality of substrate support pins is formed of a ceramic material different from quartz.

[0019] Furthermore, the ninth embodiment is a susceptor according to any of the first to eighth embodiments, in which the remaining screw holes among the plurality of screw holes are plugged.

[0020] Furthermore, a tenth aspect provides a heat treatment apparatus that heats a substrate by irradiating the substrate with light, the apparatus comprising: a chamber that accommodates the substrate; a susceptor according to any one of the first to ninth aspects, the susceptor being provided in the chamber and supporting the substrate; a continuous lighting lamp that irradiates the substrate supported by the susceptor with light to heat the substrate; and a flash lamp that irradiates the substrate supported by the susceptor with flash light. Effects of the Invention

[0021] According to the susceptor according to any one of the first to ninth aspects, a plurality of screw holes are formed in the holding plate, each of the plurality of substrate support pins has a screw portion formed with a screw thread screwed into the screw hole, and the plurality of substrate support pins are detachably provided in some of the plurality of screw holes, so that the substrate support pins can be easily replaced. In addition, it is also possible to prevent the substrate support pins from easily coming off the holding plate.

[0022] In particular, according to the susceptor according to the seventh aspect, each of the plurality of substrate support pins supports the substrate by means of a pin portion in a state where the penetrating portion loosely passes through the screw hole, so the substrate support pin can move slightly within the range of the inner diameter of the screw hole, and it is possible to suppress scratching of the back surface of the substrate even when the substrate is deformed during heat treatment.

[0023] According to the heat treatment apparatus according to the tenth aspect, since the heat treatment apparatus comprises the susceptor according to any one of the first to ninth aspects, the substrate support pins can be easily replaced, and it is also possible to prevent the substrate support pins from easily coming off the holding plate. Brief Description of the Drawings

[0024] [Figure 1] FIG. 1 is a longitudinal cross-sectional view showing the configuration of a heat treatment apparatus according to the present invention. [Figure 2] FIG. 2 is a perspective view showing the overall appearance of a holding portion. [Figure 3] FIG. 3 is a plan view of a holding plate. [Figure 4]Figure 4 is an external perspective view of the substrate support pins of the first embodiment. [Figure 5] Figure 5 shows the state in which the substrate support pins of the first embodiment are attached to the susceptor. [Figure 6] Figure 6 shows an example of a plug. [Figure 7] Figure 7 is a schematic diagram showing a semiconductor wafer supported by a susceptor. [Figure 8] Figure 8 is a plan view of the transfer mechanism. [Figure 9] Figure 9 is a side view of the transfer mechanism. [Figure 10] Figure 10 is a plan view showing the arrangement of multiple halogen lamps. [Figure 11] Figure 11 is a perspective view of the substrate support pins of the second embodiment. [Figure 12] Figure 12 shows the state in which the substrate support pins of the second embodiment are attached to the susceptor. [Modes for carrying out the invention]

[0025] 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."

[0026] <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 (in this embodiment, it is φ300 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.

[0027] 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 a halogen heating unit 4 incorporating multiple halogen lamps HL. The flash heating unit 5 is located on the upper side of the chamber 6, while the halogen 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 halogen heating unit 4, the flash heating unit 5, and the chamber 6 to perform heat treatment on the semiconductor wafer W.

[0028] 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 halogen heating section 4 into chamber 6.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] Furthermore, through-holes 61a and 61b are drilled in the side portion 61 of the chamber. Through-hole 61a is a cylindrical hole for guiding infrared light emitted from the upper surface of the semiconductor wafer W held by the susceptor 74 (described later) to the infrared sensor 29 of the upper radiation thermometer 25. On the other hand, through-hole 61b is a cylindrical hole for guiding infrared light emitted from the lower surface of the semiconductor wafer W to the lower radiation thermometer 20. Through-holes 61a and 61b are provided at an inclination with respect to the horizontal direction such that their axes in the direction of penetration intersect with the main surface of the semiconductor wafer W held by the susceptor 74. A transparent window 26 made of calcium fluoride material that transmits infrared light in the wavelength range measurable by the upper radiation thermometer 25 is attached to the end of through-hole 61a facing the heat treatment space 65. Furthermore, a transparent window 21 made of barium fluoride material that transmits infrared light in the wavelength range measurable by the lower radiation thermometer 20 is attached to the end of the through hole 61b facing the heat treatment space 65.

[0033] 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).

[0034] 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.

[0035] Furthermore, a gas exhaust pipe 191 for discharging gas from the heat treatment space 65 is connected to the tip of the transport opening 66. The gas exhaust pipe 191 is connected to the exhaust section 190 via a valve 192. By opening the valve 192, the gas in the chamber 6 is exhausted through the transport opening 66.

[0036] 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.

[0037] 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.

[0038] The susceptor 74 is supported by four connecting parts 72 provided on the base ring 71. The susceptor 74 comprises a retaining plate 75, a guide ring 76, and a plurality of substrate support pins 90. 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.

[0039] 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.

[0040] 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 90 (eight in this embodiment) are erected on the retaining surface 75a of the retaining plate 75. The manner in which the multiple substrate support pins 90 are installed on the retaining plate 75 will be described in more detail later.

[0041] Furthermore, the holding plate 75 of the susceptor 74 has an opening 78 that penetrates vertically. The opening 78 is provided for the lower radiation thermometer 20 to receive synchrotron radiation (infrared light) emitted from the lower surface of the semiconductor wafer W. That is, the lower 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 a through hole 61b 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 for the transfer of the semiconductor wafer W.

[0042] The four connecting parts 72 erected on the base ring 71 are fixed to the peripheral edge of the holding plate 75 of the susceptor 74 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.

[0043] Figure 8 is a plan view of the transfer mechanism 10. Figure 9 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 8) where the semiconductor wafer W is transferred to the holding part 7 and a retracted position (dotted line position in Figure 8) where the arms do not overlap with the semiconductor wafer W held by the holding part 7 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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 HL. 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.

[0048] 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.

[0049] The halogen heating unit 4, located below the chamber 6, has multiple halogen lamps HL (40 in this embodiment) built into the inside of the housing 41. The halogen heating unit 4 heats the semiconductor wafer W by irradiating light from below the chamber 6 through the lower chamber window 64 into the heat treatment space 65 using the multiple halogen lamps HL.

[0050] Figure 10 is a plan view showing the arrangement of multiple halogen lamps HL. The 40 halogen lamps HL are arranged in two rows, upper and lower. Twenty halogen lamps HL are arranged in the upper row, which is closer to the holding part 7, and another 20 halogen lamps HL are arranged in the lower row, which is further from the holding part 7. Each halogen lamp HL is a rod-shaped lamp with a long cylindrical shape. In both the upper and lower rows, the 20 halogen lamps HL are arranged so that their longitudinal directions are parallel to each other along the main surface of the semiconductor wafer W held by the holding part 7 (i.e., along the horizontal direction). Therefore, the planes formed by the arrangement of halogen lamps HL in both the upper and lower rows are horizontal planes.

[0051] Furthermore, as shown in Figure 10, in both the upper and lower sections, the arrangement density of halogen lamps HL is higher in the region facing the periphery of the semiconductor wafer W held by the holding section 7 than in the region facing the center. In other words, in both the upper and lower sections, the arrangement pitch of halogen lamps HL is shorter at the periphery than at the center of the lamp arrangement. Therefore, a greater amount of light can be irradiated to the periphery of the semiconductor wafer W, where temperature drops are more likely to occur during heating by light irradiation from the halogen heating section 4.

[0052] Furthermore, the lamp group consisting of halogen lamps HL in the upper row and the lamp group consisting of halogen lamps HL in the lower row are arranged to intersect in a grid pattern. In other words, a total of 40 halogen lamps HL are arranged such that the longitudinal directions of the 20 halogen lamps HL in the upper row and the longitudinal directions of the 20 halogen lamps HL in the lower row are perpendicular to each other.

[0053] The halogen lamp HL is a filament-type light source that emits light by passing an electric current through a filament placed inside a glass tube, causing the filament to become incandescent. Inside the glass tube is a gas containing trace amounts of halogen elements (iodine, bromine, etc.) introduced into an inert gas such as nitrogen or argon. By introducing halogen elements, it is possible to set the filament temperature to a high level while suppressing filament breakage. Therefore, the halogen lamp HL has the characteristics of having a longer lifespan and being able to continuously emit strong light compared to a normal incandescent light bulb. In other words, the halogen lamp HL is a continuous-lighting lamp that emits light continuously for at least 1 second or more. Furthermore, because the halogen lamp HL is a rod-shaped lamp, it has a long lifespan, and by arranging the halogen lamp HL horizontally, the radiation efficiency to the semiconductor wafer W above is excellent.

[0054] Furthermore, a reflector 43 is also provided inside the housing 41 of the halogen heating unit 4, below the two-tiered halogen lamps HL (Figure 1). The reflector 43 reflects the light emitted from the multiple halogen lamps HL towards the heat treatment space 65.

[0055] As shown in Figure 1, the heat treatment apparatus 1 includes an upper radiation thermometer 25 and a lower radiation thermometer 20. The upper radiation thermometer 25 is installed diagonally above the semiconductor wafer W held by the susceptor 74 and measures the temperature of the upper surface by receiving infrared light emitted from the upper surface of the semiconductor wafer W. The infrared sensor 29 of the upper radiation thermometer 25 is equipped with an InSb (indium antimony) optical element to respond to rapid temperature changes on the upper surface of the semiconductor wafer W at the moment of flash light irradiation. On the other hand, the lower radiation thermometer 20 is installed diagonally below the semiconductor wafer W held by the susceptor 74 and measures the temperature of the lower surface by receiving infrared light emitted from the lower surface of the semiconductor wafer W.

[0056] The control unit 3 controls the various operating mechanisms described above provided in the heat treatment apparatus 1. The configuration of the control unit 3 as hardware is the same as that of a general computer. That is, the control unit 3 includes a CPU which is a circuit that performs various arithmetic processing, a ROM which is a read-only memory for storing basic programs, a RAM which is a readable and writable memory for storing various information, and a magnetic disk for storing control software, data, and the like. Processing in the heat treatment apparatus 1 proceeds when the CPU of the control unit 3 executes a predetermined processing program.

[0057] In the present embodiment, a plurality of substrate support pins 90 are detachably provided to the susceptor 74. Figure 3 is a plan view of the holding plate 75. A plurality of screw holes 77 are formed in the disk-shaped holding plate 75 formed of quartz (32 holes in the present embodiment). The plurality of screw holes 77 are formed concentrically with different diameters. Specifically, as shown in Figure 3, eight screw holes 77 are formed along the circumference of each of a first circle C1 with a radius r1, a second circle C2 with a radius r2, a third circle C3 with a radius r3, and a fourth circle C4 with a radius r4 in order from the innermost side of the holding plate 75. The first circle C1, the second circle C2, the third circle C3, and the fourth circle C4 are concentric circles sharing the center of the holding plate 75, and have different radii from each other (r1<r2<r3<r4). Eight screw holes 77 are formed at 45° intervals along the circumference of each of the first circle C1, the second circle C2, the third circle C3, and the fourth circle C4. An internal female screw thread is formed inside each screw hole 77. Note that since there is a possibility that the screw thread may collapse if firing is performed after forming the screw thread on a member formed of quartz, it is preferable to perform thread cutting to form the screw thread after the firing finishing.

[0058] Figure 4 is an external perspective view of the substrate support pin 90 of the first embodiment. The substrate support pin 90 of the first embodiment is made of quartz. The substrate support pin 90 of the first embodiment is made up of a pin portion 91, a threaded portion 92, and a screw-fastening portion 93. The substantially hemispherical pin portion 91 is provided on the upper side (one end) of the threaded portion 92. The pin portion 91 contacts the lower surface of the semiconductor wafer W at its hemispherical upper end. The threaded portion 92 is formed by engraving threads 92a on the outer surface of a substantially cylindrical shape. The threads 92a are screwed into the screw hole 77. That is, the threaded portion 92 with threads 92a functions as a male screw for the screw hole 77 of the retaining plate 75. The substantially disc-shaped screw-fastening portion 93 is provided on the lower side (other end) of the threaded portion 92. A straight groove 93a is provided on the lower surface of the screw-fastening portion 93.

[0059] The diameter of the pin portion 91 of the substrate support pin 90 is less than or equal to the diameter of the threaded portion 92 that screws into the screw hole 77, whereas the diameter of the screw-fastening portion 93 is larger than the diameter of the threaded portion 92. That is, the planar size of the screw-fastening portion 93 viewed from above in the vertical direction is larger than the planar size of the threaded portion 92. Therefore, the pin portion 91 can pass through the screw hole 77, while the screw-fastening portion 93 cannot pass through the screw hole 77. The vertical heights of the pin portion 91, threaded portion 92, and screw-fastening portion 93 can be set to appropriate values, but the height of the threaded portion 92 is the same as the thickness of the retaining plate 75 (for example, if the thickness of the retaining plate 75 is 2 mm, the heights of the pin portion 91, threaded portion 92, and screw-fastening portion 93 should be 1 mm, 2 mm, and 1 mm, respectively).

[0060] Figure 5 shows the state in which the substrate support pin 90 of the first embodiment is attached to the susceptor 74. The substrate support pin 90 is attached by screwing it into one of the screw holes 77 from below the retaining plate 75 of the susceptor 74. Specifically, for example, an operator inserts the pin portion 91 of the substrate support pin 90 into the screw hole 77 from below the retaining plate 75 and screws the threaded portion 92 into the screw hole 77 to a certain extent by hand, and then uses a flathead screwdriver to fasten the threaded portion 92 so that the screw fastening portion 93 abuts against the lower surface of the retaining plate 75. The groove 93a of the screw fastening portion 93 is provided for fitting the tip of a flathead screwdriver. As shown in Figure 5, when the entire threaded portion 92 is screwed into the screw hole 77, the pin portion 91 protrudes from the upper surface of the retaining plate 75.

[0061] In the first embodiment, for example, the substrate support pins 90 are attached to eight of the 32 screw holes 77 provided in the retaining plate 75. For example, the substrate support pins 90 are attached to each of the eight screw holes 77 formed along the circumference of the third circle C3. That is, in the first embodiment, eight substrate support pins 90 are attached to eight screw holes 77 formed along the circumference of a circle of a single diameter. As a result, eight substrate support pins 90 are erected on the upper surface of the retaining plate 75 of the susceptor 74 at 45° intervals along the circumference of the third circle C3 with radius r3.

[0062] On the other hand, the remaining 24 screw holes 77 of the 32 screw holes 77 provided in the retaining plate 75, the ones where the substrate support pins 90 could not be installed (i.e., the screw holes 77 formed along the circumferences of the first circle C1, the second circle C2, and the fourth circle C4), are plugged with plugs 99. Figure 6 shows an example of a plug 99. The plug 99 comprises a fitting portion 99a and a knob portion 99b. The fitting portion 99a has a cylindrical shape, and its diameter is approximately equal to the inner diameter of the screw hole 77. The outer surface of the fitting portion 99a is not threaded. The knob portion 99b, provided above the fitting portion 99a, also has a roughly cylindrical shape, but its diameter is larger than the diameter of the fitting portion 99a. For each of the 24 screw holes 77 where the substrate support pins 90 were not installed, the worker inserts the fitting portion 99a of the plug 99 from above the retaining plate 75 downwards to close it. As a result, in the first embodiment, eight substrate support pins 90 are erected along the circumference of the third circle C3 on the holding plate 75 of the susceptor 74, and the remaining 24 screw holes 77 are blocked by plugs 99.

[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 halogen heating section 4, flash heating section 5, and chamber 6 due to thermal energy generated from the halogen lamp HL and flash lamp FL during the heat treatment of semiconductor wafers W. For example, water cooling pipes (not shown) are provided in the wall of the chamber 6. Furthermore, the halogen heating section 4 and flash heating section 5 are air-cooled structures that dissipate heat by forming a gas flow inside. Air is also supplied to the gap between the upper chamber window 63 and the lamp light emission window 53 to cool the flash heating section 5 and the upper chamber window 63.

[0064] Next, the processing operation of 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 processing procedure for the semiconductor wafer W described below will proceed as the control unit 3 controls each operating mechanism of the heat treatment apparatus 1.

[0065] First, the supply valve 84 is opened, and the exhaust valves 89 and 192 are 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 port 81. When valve 89 is opened, the gas inside the chamber 6 is exhausted from the gas exhaust port 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] Furthermore, when valve 192 is opened, the gas inside chamber 6 is also exhausted from the transport opening 66. In addition, the atmosphere around the drive unit of the transfer mechanism 10 is also exhausted by an exhaust mechanism (not shown). During the heat treatment of semiconductor wafers W in the heat treatment apparatus 1, nitrogen gas is continuously supplied to the heat treatment space 65, and the amount supplied is changed as appropriate according to the processing step.

[0067] 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.

[0068] 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 90 (the upper end of the pin section 91).

[0069] 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 90 erected on the holding plate 75 and held by the susceptor 74. The pair of transfer arms 11, which have descended to below the susceptor 74, are moved to a retracted position, i.e., inside the recess 62, by the horizontal movement mechanism 13.

[0070] Figure 7 is a schematic diagram showing a semiconductor wafer W supported by a susceptor 74. The pin portions 91 of eight substrate support pins 90 erected on a holding plate 75 contact the lower surface of the semiconductor wafer W to support it. In the first embodiment, the semiconductor wafer W is supported by the pin portions 91 with the threaded portions 92 of the substrate support pins 90 screwed into the threaded holes 77 of the holding plate 75. Since the height of the eight substrate support pins 90 from the holding surface 75a of the holding plate 75 (distance from the upper end of the pin portion 91 to the holding surface 75a) is uniform, the semiconductor wafer W can be supported in a horizontal position by the eight substrate support pins 90.

[0071] Furthermore, the semiconductor wafer W is held in the holding section 7 with the patterned surface 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 eight substrate support pins 90, 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 90. Therefore, horizontal displacement of the semiconductor wafer W, which is supported by multiple substrate support pins 90, is prevented by the guide ring 76.

[0072] After the semiconductor wafer W is held horizontally from below by the susceptor 74 of the holding part 7 made of silica, the 40 halogen lamps HL of the halogen heating part 4 are lit simultaneously to start preheating (assisted heating). The halogen light emitted from the halogen lamps HL passes through the lower chamber window 64 and the susceptor 74, which are 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 halogen lamps HL. The transfer arm 11 of the transfer mechanism 10 is retracted inside the recess 62, so it does not interfere with heating by the halogen lamps HL.

[0073] When preheating is performed using a halogen lamp HL, the temperature of the semiconductor wafer W is measured by a lower radiation thermometer 20. Specifically, the lower radiation thermometer 20 receives infrared light emitted from the lower surface of the semiconductor wafer W held by the susceptor 74 through an opening 78 via a transparent window 21 to measure the wafer temperature during heating. 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 halogen lamp HL, has reached a predetermined preheating temperature T1, and controls the output of the halogen lamp HL. In other words, the control unit 3 feedback-controls the output of the halogen lamp HL based on the measurement value from the lower radiation thermometer 20 so that the temperature of the semiconductor wafer W reaches the preheating temperature T1. Thus, the lower radiation thermometer 20 is a radiation thermometer for temperature control of the semiconductor wafer W during preheating.

[0074] 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 lower radiation thermometer 20, reaches the preheating temperature T1, the control unit 3 adjusts the output of the halogen lamp HL to maintain the temperature of the semiconductor wafer W at approximately the preheating temperature T1.

[0075] By performing preheating with halogen lamps HL in this manner, the entire semiconductor wafer W is uniformly heated to the preheating temperature T1. During the preheating stage with halogen lamps HL, the temperature of the peripheral parts of the semiconductor wafer W, where heat dissipation is more likely, tends to be lower than that of the central part. However, the density of halogen lamps HL in the halogen heating section 4 is higher in the region facing the peripheral parts of the semiconductor wafer W than in the region facing the central part. As a result, more light is irradiated to the peripheral parts of the semiconductor wafer W, where heat dissipation is more likely, making it possible to achieve a uniform in-plane temperature distribution of the semiconductor wafer W during the preheating stage.

[0076] 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.

[0077] The flash light emitted from the flash lamp FL is an extremely short and intense flash of light with an irradiation time of approximately 0.1 milliseconds to 100 milliseconds, obtained by converting electrostatic energy previously stored in a capacitor into an extremely short light pulse. When such an extremely short and intense flash of light enters the chamber 6 and irradiates the surface of the semiconductor wafer W, the surface temperature of the semiconductor wafer W instantaneously rises to the processing temperature T2 and then rapidly decreases.

[0078] After the flash heating process is completed, the halogen lamp HL is turned off 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 lower radiation thermometer 20, and the measurement result is transmitted to the control unit 3. The control unit 3 monitors whether the temperature of the semiconductor wafer W has cooled down to a predetermined temperature based on the measurement result of the lower 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.

[0079] In the first embodiment, a plurality of screw holes 77 are formed in the retaining plate 75 of the susceptor 74. The substrate support pin 90 is formed with a pin portion 91 that contacts the semiconductor wafer W, a threaded portion 92 having threads 92a that screw into the screw holes 77, and a screw-fastening portion 93 having a larger planar size than the threaded portion 92. The threaded portion 92 is screwed into some of the plurality of screw holes 77 formed in the retaining plate 75, and a plurality of substrate support pins 90 are attached to the susceptor 74. Therefore, the operator can easily attach or detach the substrate support pin 90 to the retaining plate 75 by simply rotating the substrate support pin 90 clockwise or counterclockwise. In other words, a plurality of substrate support pins 90 are detachably provided in some of the plurality of screw holes 77 of the retaining plate 75. For this reason, the operator can easily replace the substrate support pin 90.

[0080] In this configuration, even without threading the retaining plate 75 and the substrate support pins 90, simply inserting pin-shaped members into some of the multiple holes provided in the retaining plate 75 would allow the substrate support pins to be easily attached to and removed from those holes, making it possible to easily replace the substrate support pins. However, in such a configuration, when the transfer arm 11 rises after heat treatment and lifts the semiconductor wafer W from the susceptor 74, the substrate support pins may adhere to the underside of the semiconductor wafer W and come loose from the susceptor 74. In the first embodiment, since the threaded portion 92 of the substrate support pin 90 is screwed into the threaded hole 77 of the retaining plate 75 and the pin portion 91 supports the semiconductor wafer W, there is no risk of the substrate support pins 90 coming loose from the retaining plate 75 when the semiconductor wafer W is lifted from the susceptor 74 after heat treatment.

[0081] Furthermore, in the first embodiment, since the substrate support pins 90 are detachably provided on the retaining plate 75, when changing the pulse width of the flash light emitted from the flash lamp FL, it is not necessary to replace the entire susceptor 74, and only the installation position of the substrate support pins 90 on the retaining plate 75 can be easily changed. For example, when changing the installation position of the substrate support pins 90 from the third circle C3 to the second circle C2 in order to lengthen the pulse width of the emitted flash light, the operator only needs to remove the eight substrate support pins 90 attached along the circumference of the third circle C3 and replace them with the eight screw holes 77 provided along the circumference of the second circle C2. Therefore, it is preferable to form the screw holes 77 in positions corresponding to the pulse widths of the flash light that may be used.

[0082] Furthermore, when changing the installation position of the board support pins 90, it is not necessary to design and manufacture the entire susceptor; it is sufficient to simply swap the board support pins 90. Therefore, the installation position of the board support pins 90 can be changed in a relatively short time. Moreover, the installation position of the board support pins 90 can be changed at a lower cost compared to manufacturing the entire susceptor.

[0083] Furthermore, in the first embodiment, if contamination, damage, or wear occurs to the substrate support pin 90, only that substrate support pin 90 can be easily replaced. In addition, if the shape of the tip of the substrate support pin 90 (shape of the pin portion 91) needs to be changed, the substrate support pin 90 can also be easily replaced.

[0084] <Second Embodiment> Next, a second embodiment of the present invention will be described. The overall configuration of the heat treatment apparatus 1 in the second embodiment is generally the same as that of the first embodiment. The processing procedure for the semiconductor wafer W in the second embodiment is also the same as that of the first embodiment. The difference between the second embodiment and the first embodiment is the shape of the substrate support pins. The holding plate 75 in the second embodiment is the same as that in the first embodiment.

[0085] Figure 11 is an external perspective view of the substrate support pin 95 of the second embodiment. The substrate support pin 95 of the second embodiment is made of silicon carbide (SiC). The substrate support pin 95 of the second embodiment is made up of a pin portion 96, a through portion 97, and a threaded portion 98. The pin portion 96 is formed in a substantially hemispherical shape, similar to the pin portion 91 of the first embodiment, and its upper hemispherical end contacts the lower surface of the semiconductor wafer W. The threaded portion 98 is formed by engraving threads 98a on the outer surface of a substantially cylindrical shape. The threads 98a are screwed into the threaded hole 77. That is, the threaded portion 98 with threads 98a functions as a male thread for the threaded hole 77 of the retaining plate 75. A groove 98b is provided in a straight line on the lower surface of the threaded portion 98.

[0086] In the second embodiment, the substrate support pin 95 is formed by connecting a pin portion 96 and a threaded portion 98 with a through portion 97. That is, the through portion 97 is provided above the threaded portion 98, and the pin portion 96 is provided above the through portion 97. The through portion 97 is formed in a substantially cylindrical shape, and its diameter is smaller than the diameter of the threaded portion 98. Therefore, the through portion 97 can pass through the screw hole 77 with a certain clearance. Also, the maximum diameter of the pin portion 96 in the second embodiment is larger than the inner diameter of the screw hole 77. Therefore, the pin portion 96 in the second embodiment cannot pass through the screw hole 77. The heights of the pin portion 96, the through portion 97, and the threaded portion 98 along the vertical direction can be set to appropriate values, but the height of the through portion 97 is greater than the thickness of the retaining plate 75.

[0087] Figure 12 shows the state in which the substrate support pin 95 of the second embodiment is attached to the susceptor 74. In the second embodiment, the substrate support pin 95 is attached by screwing it into one of the screw holes 77 from above the retaining plate 75 of the susceptor 74. Specifically, for example, an operator inserts the threaded portion 98 of the substrate support pin 95 into the screw hole 77 to a certain extent by hand from above the retaining plate 75, and then rotates the substrate support pin 95 using a flathead screwdriver until the threaded portion 98 comes out from the bottom surface of the retaining plate 75. The groove 98b of the threaded portion 98 is provided for fitting the tip of a flathead screwdriver.

[0088] As shown in Figure 12, in the second embodiment, the threaded portion 98 protrudes downward from the lower surface of the retaining plate 75, and the pin portion 96 engages with the upper surface of the retaining plate 75 with the through portion 97 loosely passing through the screw hole 77 with a certain clearance, thereby attaching the substrate support pin 95 to the susceptor 74. Although the threaded portion 98 is screwed into the screw hole 77 during the process of attaching the substrate support pin 95, it is not screwed into the screw hole 77 when the substrate support pin 95 is attached to the retaining plate 75. In other words, in the second embodiment, the semiconductor wafer W is supported by the pin portion 91 with the through portion 97 of the substrate support pin 95 loosely passing through the screw hole 77.

[0089] In the second embodiment as well, substrate support pins 95 are attached to some of the 32 screw holes 77 provided in the retaining plate 75. For example, substrate support pins 95 are attached to each of the 8 screw holes 77 formed along the circumference of the second circle C2. As a result, 8 substrate support pins 95 are erected on the upper surface of the retaining plate 75 of the susceptor 74 at 45° intervals along the circumference of the second circle C2 with radius r2. Also, as in the first embodiment, the remaining 24 screw holes 77 of the retaining plate 75 that do not have substrate support pins 95 attached are plugged with plugs 99.

[0090] When performing heat treatment on a semiconductor wafer W, the pin portions 96 of eight substrate support pins 95 provided on the holding plate 75 contact the lower surface of the semiconductor wafer W to support the semiconductor wafer W. In the first embodiment, the semiconductor wafer W was supported by substrate support pins 90 in which the threaded portion 92 was screwed into the screw hole 77, whereas in the second embodiment, the semiconductor wafer W is supported by substrate support pins 95 in which the threaded portion 98 is disengaged from the screw hole 77 and the through portion 97 is loosely inserted into the screw hole 77, and heat treatment (preheating and flash heating) is performed.

[0091] In the second embodiment, a plurality of screw holes 77 are formed in the retaining plate 75 of the susceptor 74. The substrate support pin 95 is formed with a pin portion 96 that contacts the semiconductor wafer W, a threaded portion 98 with threads 98a that screw into the screw holes 77, and a cylindrical through portion 97 with a smaller diameter than the threaded portion 98. The plurality of substrate support pins 95 are attached to the susceptor 74 by screwing the threaded portion 98 into some of the plurality of screw holes 77 formed in the retaining plate 75. Therefore, the operator can easily attach or detach the substrate support pin 95 to the retaining plate 75 by simply rotating the substrate support pin 95 clockwise or counterclockwise. In other words, similar to the first embodiment, the plurality of substrate support pins 95 are detachably provided in some of the plurality of screw holes 77 of the retaining plate 75. Therefore, the operator can easily replace the substrate support pin 95.

[0092] Furthermore, since it is impossible to remove the substrate support pin 95 from the retaining plate 75 without going through the process of the threaded portion 98 being screwed into the threaded hole 77, just as in the first embodiment, there is no risk of the substrate support pin 95 coming out of the retaining plate 75 when the heat-treated semiconductor wafer W is lifted from the susceptor 74.

[0093] Furthermore, in the second embodiment as well, since the substrate support pins 95 are detachably provided on the retaining plate 75, when changing the pulse width of the flash light emitted from the flash lamp FL, it is not necessary to replace the entire susceptor 74, and only the installation position of the substrate support pins 95 on the retaining plate 75 can be easily changed. In addition, if contamination, damage, or wear occurs to the substrate support pins 95, only those substrate support pins 95 can be easily replaced.

[0094] In particular, in the second embodiment, the semiconductor wafer W is supported by a substrate support pin 95, which is installed with the threaded portion 98 disengaged from the screw hole 77 and the through portion 97 loosely penetrating the screw hole 77 with a certain clearance, and the heat treatment is performed. As a result, the substrate support pin 95 can move slightly laterally within the range of the inner diameter of the screw hole 77, and even when the semiconductor wafer W deforms due to thermal expansion during heat treatment, it is possible to suppress damage to the lower surface of the semiconductor wafer W.

[0095] Furthermore, considering the uniformity of the in-plane temperature distribution of the semiconductor wafer W during heat treatment and the generation of scratches on the lower surface, it may be preferable to form the substrate support pins 95 from ceramics, which are different from quartz (for example, in the second embodiment, the substrate support pins 95 are formed from silicon carbide). However, since the thermal expansion coefficients of quartz and ceramics that form the retaining plate 75 are different (generally, ceramics have a higher thermal expansion coefficient than quartz), there is a risk that the retaining plate 75 or the substrate support pins may be damaged when the susceptor 74 heats up during heat treatment. In the second embodiment, the substrate support pins 95 are attached to the retaining plate 75 with a certain clearance between the through-hole 97 and the screw hole 77, so that the difference in their thermal expansion coefficients can be absorbed by the clearance when the retaining plate 75 and the substrate support pins 95 expand during heat treatment. As a result, damage to the retaining plate 75 and the substrate support pins 95 can be prevented even when the susceptor 74 heats up during heat treatment.

[0096] <Variation> While embodiments of the present invention have been described above, various modifications can be made to this invention without departing from its spirit. For example, the configuration in which the retaining plate 75 has multiple screw holes 77 is not limited to the example in Figure 3 and can be changed as appropriate. For example, in the example in Figure 3, multiple screw holes 77 were provided along the circumference of four concentric circles of different diameters, but the multiple screw holes 77 may be provided in three or fewer concentric circles, or in five or more concentric circles. Also, in the example in Figure 3, multiple screw holes 77 were formed at equal intervals along the circumference of each concentric circle, but this is not limited to this, and the screw holes 77 may be formed at uneven intervals along the circumference of the concentric circles. Furthermore, the multiple screw holes 77 do not necessarily have to be formed in a concentric circle. In short, it is sufficient to form the screw holes 77 at the positions of the retaining plate 75 where substrate support pins may be installed.

[0097] Furthermore, in each of the above embodiments, a substrate support pin 90 was attached to each of the eight screw holes 77 formed along the circumference of a single diameter. Alternatively, the substrate support pins 90 may be attached to each of the multiple screw holes 77 formed along the circumferences of two or more different diameters. For example, four substrate support pins 90 may be attached at 90° intervals along the circumference of a second circle C2 with radius r2, and four substrate support pins 90 may be attached at 90° intervals along the circumference of a third circle C3 with radius r3.

[0098] Furthermore, although the substrate support pins 95 were formed of silicon carbide in the second embodiment, the invention is not limited to this, and they may be formed of other ceramics different from quartz (for example, aluminum oxide (Al2O3)). Alternatively, the substrate support pins 95 in the second embodiment may be formed of quartz.

[0099] Furthermore, while the flash heating unit 5 is equipped with 30 flash lamps FL in each of the above embodiments, 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. Similarly, the number of halogen lamps HL provided in the halogen heating unit 4 is not limited to 40, but can be any number.

[0100] Furthermore, in each of the above embodiments, a filament-type halogen lamp HL was used as a continuous-lighting lamp that emitted light continuously for 1 second or more to preheat the semiconductor wafer W. However, the invention is not limited to this, and a discharge-type arc lamp (for example, a xenon arc lamp) or an LED lamp may be used as a continuous-lighting lamp instead of the halogen lamp HL to perform preheating. [Explanation of symbols]

[0101] 1 Heat treatment apparatus 3. Control Unit 4. Halogen heating section 5. Flash heating section 6 chambers 7 Holding part 10 Transfer mechanism 20 Lower radiation thermometer 25 Upper radiation thermometer 63 Upper chamber window 64 Lower chamber window 65 Heat treatment space 74 Susceptors 75 Retaining plate 77 screw holes 90, 95 PCB support pins 91, 96 pin section 92,98 Threaded section 93 Screw fastening part 97 Penetration section 99 plugs FL Flash Lamp HL halogen lamp W Semiconductor wafer

Claims

1. A susceptor that supports a substrate heated by light irradiation, A flat retaining plate made of quartz, The retaining plate is provided with a plurality of substrate support pins that support the substrate, Equipped with, The retaining plate has multiple screw holes formed in it. Each of the plurality of substrate support pins has a threaded portion with a thread that fits into the screw hole, A susceptor in which the plurality of substrate support pins are detachably provided in some of the screw holes among the plurality of screw holes.

2. In the susceptor according to claim 1, The aforementioned multiple screw holes are formed in a susceptor with concentric circles of different diameters.

3. In the susceptor according to claim 2, The plurality of substrate support pins are provided in a susceptor that is formed in some of the screw holes that are shaped along the circumference of a circle of a single diameter.

4. In the susceptor according to claim 2, The plurality of substrate support pins are provided in a susceptor that is formed along the circumference of two or more different diameters and is located in some of the screw holes.

5. In the susceptor according to claim 1, Each of the plurality of substrate support pins is provided with a pin portion that contacts the substrate on the upper side of the threaded portion, and a screw-fastening portion having a larger planar size than the threaded portion on the lower side of the threaded portion. Each of the plurality of substrate support pins is a susceptor that supports the substrate by the pin portion with the threaded portion screwed into the threaded hole.

6. In the susceptor according to claim 5, Each of the aforementioned plurality of substrate support pins is a susceptor formed of quartz.

7. In the susceptor according to claim 1, Each of the plurality of substrate support pins is provided with a cylindrical through-hole having a smaller diameter than the threaded portion on the upper side of the threaded portion, and further provided with a pin portion that contacts the substrate on the upper side of the through-hole. Each of the plurality of substrate support pins is a susceptor that supports the substrate by the pin portion with the through portion loosely passing through the screw hole.

8. In the susceptor according to claim 7, Each of the aforementioned substrate support pins is a susceptor formed from a ceramic material different from quartz.

9. In the susceptor according to claim 1, A susceptor in which the remaining screw holes among the aforementioned multiple screw holes are blocked by plugs.

10. A heat treatment apparatus that heats a substrate by irradiating it with light, A chamber for housing the aforementioned substrate, A susceptor according to any one of claims 1 to 9, provided within the chamber and supporting the substrate, A continuous-lighting lamp that heats the substrate by irradiating it with light, which is supported by the susceptor, A flash lamp that irradiates the substrate supported by the susceptor with flash light, A heat treatment apparatus equipped with the following features.

Images