Heat treatment apparatus and heat treatment method

Abstract

To provide a heat treatment device and heat treatment method that speeds up the cooling rate of a substrate after heat treatment.SOLUTION: A heat treatment device 1 heats a semiconductor wafer W by irradiating the semiconductor wafer W with light. The heat treatment device 1 includes a quartz plate 100 that cools the semiconductor wafer W after being heated, and a moving mechanism (elevating mechanism 14) that relatively moves the quartz plate 100 between a contact position where the quartz plate 100 contacts the back surface Wb of the semiconductor wafer W, and a separation position where the quartz plate 100 is separated from the semiconductor wafer W.SELECTED DRAWING: Figure 11

Description

[Technical Field]

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

[0002] Flash lamp annealing (FLA), which heats semiconductor wafers in an extremely short time, is attracting attention in the semiconductor device manufacturing process.Flash lamp annealing is a heat treatment technology that uses a xenon flash lamp (hereinafter, simply referred to as "flash lamp" 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 (a few milliseconds or less).

[0003] The spectral distribution of radiation from a xenon flash lamp is in the ultraviolet to near-infrared range, with a shorter wavelength than conventional halogen lamps and a wavelength that roughly matches the fundamental absorption band of silicon semiconductor wafers. Therefore, when a semiconductor wafer is irradiated with flash light from a xenon flash lamp, little light is transmitted, making it possible to rapidly heat the semiconductor wafer. It has also been found that if the flash light is irradiated for an extremely short period of time, less than a few milliseconds, it is possible to selectively heat only the area near the surface of the semiconductor wafer.

[0004] Such flash lamp annealing is used in processes that require heating for an extremely short period of time, such as activating impurities implanted in a semiconductor wafer. By irradiating the surface of a semiconductor wafer into which impurities have been implanted by ion implantation with flash light from a flash lamp, the surface of the semiconductor wafer can be heated to the activation temperature in an extremely short period of time, allowing only impurity activation to be performed without deep diffusion of the impurities.

[0005] In a flash lamp annealing system, the backside of the semiconductor wafer is typically irradiated with light from a halogen lamp to preheat it to a certain temperature, and then the front side of the semiconductor wafer is irradiated with flash light to raise the temperature to the desired processing temperature and activate the impurities.

[0006] Regarding such an apparatus using flash lamp annealing, Patent Document 1 discloses an apparatus in which a cooling gas is supplied into a chamber after the flash heating process is completed. According to the apparatus disclosed in Patent Document 1, the semiconductor wafer, which is at a relatively high temperature immediately after flash heating, is cooled by supplying the cooling gas into the chamber.

[0007] Furthermore, with regard to other devices that use flash lamp annealing, Patent Document 2 discloses a device that can vary the distance between a semiconductor wafer and a susceptor. The device disclosed in Patent Document 2 controls the distance between the substrate and a plate-like member to a first distance during the temperature increase process of the substrate supported by a support, and to a second distance during the temperature retention process in which the substrate is maintained at a target temperature. The device described in Patent Document 2 improves the controllability of the substrate temperature during light irradiation heating. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2021-044372 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-175630 Summary of the Invention [Problem to be solved by the invention]

[0009] In recent years, there has been a demand for increasing the rate at which the substrate temperature is lowered after heat treatment in order to prevent the inactivation of impurities activated by the heat treatment. However, the techniques disclosed in Patent Documents 1 and 2 have had difficulty in achieving the temperature lowering rate required in recent years.

[0010] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a heat treatment apparatus and a heat treatment method that can increase the rate at which the temperature of a substrate decreases after heat treatment. [Means for solving the problem]

[0011] In order to solve the above problem, the invention of claim 1 is a heat treatment apparatus for heating a substrate by irradiating the substrate with light, the heat treatment apparatus comprising: a chamber for accommodating the substrate; a holder for holding the substrate in the chamber; and a heating element for heating the substrate held by the holder. A flash of light in which electrostatic energy previously stored in a capacitor is converted into a light pulse of 0.1 milliseconds or 100 milliseconds a quartz plate that cools the substrate after it has been heated by the light irradiation unit; a moving mechanism that moves the quartz plate or the substrate relatively between a contact position where the quartz plate contacts the front or back surface of the substrate and a separation position where the quartz plate is separated from the substrate; and a control unit that controls the operation of the moving mechanism. The control unit controls the movement mechanism so that the quartz plate or the substrate moves to the contact position 0.1 to 3 seconds after the substrate reaches the maximum temperature due to the flash light irradiation from the light irradiation unit. It is characterized by:

[0013] Also, claims 2 The invention is 1 to In the heat treatment apparatus described in the specification, the planar size of the quartz plate is within ±20% of the planar size of the substrate.

[0014] Also, claims 3 The invention of claim 1 or claim 2 In the heat treatment apparatus described above, a recess or a projection is formed on the surface of the quartz plate that comes into contact with the substrate.

[0015] Also, claims 4 The invention is 3 In the heat treatment apparatus described in the above, the recessed portion is a linear groove.

[0016] Also, claims 5 The present invention is a heat treatment method for heating a substrate by irradiating the substrate with light, the method comprising: irradiating the substrate with light in a chamber that accommodates the substrate; and irradiating the substrate with light in a chamber that accommodates the substrate. A flash of light in which electrostatic energy previously stored in a capacitor is converted into a light pulse of 0.1 milliseconds or 100 milliseconds and a cooling step of, after the heating step, moving a quartz plate relative to the heated substrate and bringing the quartz plate into contact with the front or back surface of the substrate to cool the substrate. In the cooling step, the substrate and the quartz plate are brought into contact with each other 0.1 to 3 seconds after the substrate reaches the maximum temperature due to the flash irradiation. It is characterized by: [Effects of the Invention]

[0024] Claim 1 and claim 2 According to the invention, the apparatus includes a quartz plate that cools the substrate after it has been heated by the light irradiation unit, and a moving mechanism that moves the quartz plate or the substrate relatively between a contact position where the quartz plate contacts the front or back surface of the substrate and a spaced position where the quartz plate is spaced from the substrate, so that by bringing the quartz plate into contact with the substrate after the heat treatment, the rate at which the temperature of the substrate decreases after the heat treatment can be increased, thereby preventing the inactivation of impurities in an active state in the substrate.

[0025] Claim 3 According to the invention, recesses or protrusions are formed on the surface of the quartz plate that contacts the substrate, which can promote separation between the substrate and the quartz plate that are in contact with each other.

[0026] Claim 4 According to the invention, the recesses are linear grooves, so that the recesses can be easily formed in the quartz plate.

[0027] Claim of 5 According to the invention, a cooling step is provided in which a quartz plate is moved relative to a heated substrate and the quartz plate is brought into contact with the front or back surface of the substrate to cool the substrate. By bringing the quartz plate into contact with the substrate after the heat treatment, the rate at which the substrate cools after the heat treatment can be increased. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a vertical 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 the holding portion. [Figure 3] FIG. [Figure 4] FIG. [Figure 5] FIG. 2 is a partial cross-sectional view showing a partial cross section of a quartz plate. [Figure 6] FIG. [Figure 7] FIG. [Figure 8] 2 is a flow chart showing a processing operation in the heat treatment apparatus of FIG. 1. [Figure 9] FIG. 2 is a side view showing a susceptor with a semiconductor wafer, a quartz plate, and lift pins. [Figure 10] FIG. 2 is a side view showing a susceptor with a semiconductor wafer, a quartz plate, and lift pins. [Figure 11] FIG. 2 is a side view showing a susceptor with a semiconductor wafer, a quartz plate, and lift pins. [Figure 12] 10 is a graph showing the temperature change over time of a semiconductor wafer in the heat treatment apparatus of the present embodiment. [Figure 13] FIG. 10 is a side view showing a susceptor according to a first modification of the first embodiment, together with a semiconductor wafer, a quartz plate, and lift pins. [Figure 14] FIG. 10 is a side view showing a susceptor according to a second modification of the first embodiment, together with a semiconductor wafer, a quartz plate, and lift pins. [Figure 15] FIG. 10 is a side view showing a susceptor according to a third modification of the first embodiment, together with a semiconductor wafer, a quartz plate, and lift pins. [Figure 16] 1 is a vertical cross-sectional view showing the configuration of a heat treatment apparatus for carrying out a heat treatment method according to the present invention. [Figure 17] FIG. 10 is a flow chart showing the flow of heat treatment of a semiconductor wafer by the heat treatment apparatus of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0032] First Embodiment FIG. 1 is a vertical cross-sectional view showing the configuration of a heat treatment apparatus 1 according to the present invention. The heat treatment apparatus 1 in FIG. 1 is a flash lamp annealing apparatus that heats a disk-shaped semiconductor wafer W as a substrate by irradiating the semiconductor wafer W with flash light. The size of the semiconductor wafer W to be treated is not particularly limited, but is, for example, φ300 mm or φ450 mm (φ300 mm in this embodiment). Note that in FIG. 1 and the subsequent figures, the dimensions and number of various parts are exaggerated or simplified as necessary for ease of understanding.

[0033] Heat treatment apparatus 1 includes a chamber 6 that accommodates a semiconductor wafer W, a flash heating unit 5 as a flash light irradiation unit incorporating multiple flash lamps FL, and a halogen heating unit 4 as a halogen light irradiation unit incorporating multiple halogen lamps HL. The flash heating unit 5 is provided above chamber 6, and the halogen heating unit 4 is provided below chamber 6. Heat treatment apparatus 1 also includes a holder 7 inside chamber 6 that holds the semiconductor wafer W in a horizontal position, and a transfer mechanism 10 that transfers the semiconductor wafer W between holder 7 and the outside of the apparatus. Heat treatment apparatus 1 also includes a controller 3 that controls the operating mechanisms provided in the halogen heating unit 4, flash heating unit 5, and chamber 6 to perform heat treatment on the semiconductor wafer W.

[0034] The flash heating unit 5, which is provided above the chamber 6, is configured with a light source consisting of multiple (30 in this embodiment) flash lamps FL (e.g., xenon flash lamps) inside a housing 51, and a reflector 52 provided to cover the light source from above. A lamp light emission window 53 is attached to the bottom of the housing 51 of the flash heating unit 5. The lamp light emission window 53, which forms the floor of the flash heating unit 5, is a plate-shaped quartz window made of quartz. By installing the flash heating unit 5 above the chamber 6, the lamp light emission window 53 faces the upper chamber window 63. The flash lamps FL irradiate flash light from above the chamber 6 into the heat treatment space 65 through the lamp light emission window 53 and the upper chamber window 63.

[0035] The multiple flash lamps FL are each a rod-shaped lamp having a long cylindrical shape, and are arranged in a plane so that their longitudinal directions are parallel to each other along the main surface of the semiconductor wafer W held by the holder 7 (i.e., along the horizontal direction). Therefore, the plane formed by the arrangement of the flash lamps FL is also a horizontal plane.

[0036] A flash lamp FL typically comprises a rod-shaped glass tube (discharge tube) filled with xenon gas and fitted with an anode and cathode connected to a capacitor at both ends, and a trigger electrode attached to the outer surface of the glass tube. Because xenon gas is an electrical insulator, electricity does not flow through the glass tube under normal conditions, even if a charge is stored in the capacitor. However, when a high voltage is applied to the trigger electrode, the insulation breaks down, and the electricity stored in the capacitor flows instantaneously through the glass tube, exciting the xenon atoms or molecules and emitting light. This flash lamp FL converts electrostatic energy previously stored in the capacitor into extremely short light pulses of 0.1 to 100 milliseconds, enabling it to emit light that is significantly stronger than continuous light sources such as halogen lamps HL. In other words, a flash lamp FL is a pulsed lamp that emits light instantaneously for an extremely short period of time, less than one second. The light-emitting duration of the flash lamp FL can be adjusted by adjusting the coil constant of the lamp power supply that supplies power to the flash lamp FL.

[0037] Furthermore, reflector 52 is provided above the multiple flash lamps FL so as to cover them entirely. The basic function of reflector 52 is to reflect the flash light emitted from the multiple flash lamps FL toward the heat treatment space 65. Reflector 52 is made of an aluminum alloy plate, and its surface (the surface facing the flash lamps FL) is roughened by blasting.

[0038] The halogen heating unit 4, which is provided below the chamber 6, has a plurality of 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 the plurality of halogen lamps HL from below the chamber 6 through a lower chamber window 64 into a heat treatment space 65.

[0039] The halogen lamps HL that make up the halogen heating unit 4 are arranged, for example, in two rows, upper and lower, with 40 lamps (see FIG. 1). 20 halogen lamps HL are arranged in the upper row, which is closer to the holder 7, and 20 halogen lamps HL are also arranged in the lower row, which is farther from the holder 7 than the upper row. Each halogen lamp HL is a rod-shaped lamp having 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 holder 7 (i.e., along the horizontal direction). Therefore, the plane formed by the arrangement of the halogen lamps HL in both the upper and lower rows is a horizontal plane.

[0040] Furthermore, on both the upper and lower tiers, the halogen lamps HL are arranged more densely in the region facing the periphery of the semiconductor wafer W held by the holder 7 than in the region facing the center of the semiconductor wafer W. That is, on both the upper and lower tiers, the halogen lamps HL are arranged at a shorter pitch in the periphery of the lamp arrangement than in the center. This allows a greater amount of light to be irradiated onto the periphery of the semiconductor wafer W, which is prone to temperature drop during heating due to light irradiation from the halogen heating unit 4.

[0041] The lamp group consisting of the halogen lamps HL on the upper row and the lamp group consisting of the halogen lamps HL on the lower row are arranged so as to intersect in a grid pattern. That is, a total of 40 halogen lamps HL are arranged so that the longitudinal direction of the 20 halogen lamps HL arranged on the upper row and the longitudinal direction of the 20 halogen lamps HL arranged on the lower row are perpendicular to each other.

[0042] A halogen lamp HL is a filament-type light source that emits light by passing electricity through a filament placed inside a glass tube, causing it to incandescent. The glass tube is filled with an inert gas, such as nitrogen or argon, containing trace amounts of halogen elements (iodine, bromine, etc.). The introduction of halogen elements makes it possible to set the filament temperature at a high temperature while preventing filament breakage. Therefore, compared to standard incandescent light bulbs, halogen lamps HL have the characteristics of a longer lifespan and the ability to continuously emit strong light. In other words, halogen lamps HL are continuous lamps that emit light continuously for at least one second. Furthermore, because halogen lamps HL are rod-shaped, they have a long lifespan, and by arranging them horizontally, they achieve excellent radiation efficiency toward the semiconductor wafer W above.

[0043] Also, a reflector 43 is provided below the two-tiered halogen lamps HL inside the housing 41 of the halogen heating unit 4 (see FIG. 1). The reflector 43 reflects the light emitted from the multiple halogen lamps HL toward the heat treatment space 65.

[0044] As shown in FIG. 1 , the chamber 6 is provided with two radiation thermometers (pyrometers in this embodiment): 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 on the susceptor 74 and receives infrared light radiated from the top surface of the semiconductor wafer W to measure the temperature of the top surface. The infrared sensor 29 of the upper radiation thermometer 25 is equipped with an InSb (indium antimonide) optical element so as to be able to respond to a sudden temperature change on the top surface of the semiconductor wafer W at the moment when the flash light is irradiated. On the other hand, the lower radiation thermometer 20 is installed diagonally below the semiconductor wafer W held on the susceptor 74 and receives infrared light radiated from the bottom surface of the semiconductor wafer W to measure the temperature of the bottom surface.

[0045] The control unit 3 controls the various operating mechanisms provided in the heat treatment device 1. The hardware configuration of the control unit 3 is similar to 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 that stores basic programs, a RAM, which is a readable and writable memory that stores various information, and a magnetic disk that stores control software, data, and the like. The CPU of the control unit 3 executes a predetermined processing program, thereby causing the processing in the heat treatment device 1 to proceed. The transfer mechanism 10 is also controlled by the control unit 3. That is, the control unit 3 controls the operation of the lifting mechanism 14 and horizontal movement mechanism 13 that constitute the transfer mechanism 10.

[0046] 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 unit 4, flash heating unit 5, and chamber 6 due to the thermal energy generated by the halogen lamps HL and flash lamps FL during heat treatment of the semiconductor wafer W. For example, a water-cooled pipe (not shown) is provided in the wall of the chamber 6. The halogen heating unit 4 and flash heating unit 5 also have an air-cooled structure that creates a gas flow inside to remove heat. 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 unit 5 and upper chamber window 63.

[0047] The chamber 6 is configured by attaching quartz chamber windows to the top and bottom of a cylindrical chamber side portion 61. The chamber side portion 61 has a roughly cylindrical shape with openings at the top and bottom, with an upper chamber window 63 attached and closing the upper opening, and a lower chamber window 64 attached and closing the lower opening. The upper chamber window 63, which forms the ceiling of the 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 unit 5 into the chamber 6. The lower chamber window 64, which forms the floor of the chamber 6, is also a disc-shaped member made of quartz and functions as a quartz window that transmits light from the halogen heating unit 4 into the chamber 6. The heat treatment apparatus 1 heats the semiconductor wafer W by irradiating it with light in this manner.

[0048] Furthermore, a reflective ring 68 is attached to the upper part of the inner wall surface of the chamber side 61, and a reflective ring 69 is attached to the lower part. Both reflective rings 68, 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 61. On the other hand, the lower reflective ring 69 is attached by fitting it from the lower side of the chamber side 61 and fastening it with screws (not shown). In other words, both reflective rings 68, 69 are detachably attached to the chamber side 61. The internal space of the chamber 6, i.e., the space surrounded by the upper chamber window 63, the lower chamber window 64, the chamber side 61, and the reflective rings 68, 69, is defined as a heat treatment space 65.

[0049] By attaching the reflecting rings 68, 69 to the chamber side portion 61, a recess 62 is formed on the inner wall surface of the chamber 6. That is, the recess 62 is formed by a central portion of the inner wall surface of the chamber side portion 61 where the reflecting rings 68, 69 are not attached, the lower end surface of the reflecting ring 68, and the upper end surface of the reflecting 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 holder 7 that holds the semiconductor wafer W. The chamber side portion 61 and the reflecting rings 68, 69 are made of a metal material (e.g., stainless steel) that has excellent strength and heat resistance.

[0050] Furthermore, a transfer opening (furnace port) 66 is formed in the chamber side portion 61, through which a semiconductor wafer W is loaded into and unloaded from the chamber 6. The transfer opening 66 can be opened and closed by a gate valve 185. The transfer opening 66 is connected to the outer peripheral surface of the recessed portion 62. Therefore, when the gate valve 185 opens the transfer opening 66, the semiconductor wafer W can be loaded into and unloaded from the heat treatment space 65 through the transfer opening 66 and the recessed portion 62. Furthermore, when the gate valve 185 closes the transfer opening 66, the heat treatment space 65 in the chamber 6 becomes an airtight space.

[0051] Furthermore, through holes 61a and 61b are formed in the chamber side portion 61. The through hole 61a is a cylindrical hole for guiding infrared light radiated from the upper surface of a semiconductor wafer W held on a susceptor 74 (described later) to the infrared sensor 29 of the upper radiation thermometer 25. On the other hand, the through hole 61b is a cylindrical hole for guiding infrared light radiated from the lower surface of the semiconductor wafer W to the infrared sensor 24 of the lower radiation thermometer 20. The through holes 61a and 61b are provided at an angle with respect to the horizontal direction so that their axes of penetration intersect with the main surface of the semiconductor wafer W held on the susceptor 74. A transparent window 26 made of calcium fluoride material that transmits infrared light in a wavelength range measurable by the upper radiation thermometer 25 is attached to the end of the 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 that can be measured by the lower radiation thermometer 20 is attached to the end of the through hole 61b facing the heat treatment space 65.

[0052] Gas supply holes 81 are formed in the upper part of the inner wall of the chamber 6 to supply processing gas to the heat treatment space 65. The gas supply holes 81 are formed at a position above the recess 62 and may be provided in the reflecting ring 68. The gas supply holes 81 are 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 inserted in 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 has flowed into the buffer space 82 spreads within the buffer space 82, which has lower fluid resistance than the gas supply holes 81, and is supplied from the gas supply holes 81 into the heat treatment space 65. The processing gas may be, for example, an inert gas such as nitrogen (N), a reactive gas such as hydrogen (H) or ammonia (NH), or a mixture thereof (nitrogen gas in this embodiment).

[0053] Meanwhile, a gas exhaust hole 86 is formed in the lower part of the inner wall of the chamber 6 to exhaust gas from the heat treatment space 65. The gas exhaust hole 86 is formed below the recess 62 and may be provided in the reflecting ring 69. The gas exhaust hole 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 an exhaust unit 190. A valve 89 is inserted in the gas exhaust pipe 88. When the valve 89 is opened, the gas in the heat treatment space 65 is exhausted from the gas exhaust hole 86 through the buffer space 87 to the gas exhaust pipe 88. The gas supply hole 81 and the gas exhaust hole 86 may be provided in multiple numbers along the circumferential direction of the chamber 6, or may be slit-shaped. The process gas supply source 85 and the exhaust unit 190 may be mechanisms provided in the heat treatment apparatus 1 or may be utilities of a factory where the heat treatment apparatus 1 is installed.

[0054] A gas exhaust pipe 191 for discharging gas from the heat treatment space 65 is also connected to the tip of the transfer opening 66. The gas exhaust pipe 191 is connected to an exhaust unit 190 via a valve 192. By opening the valve 192, the gas in the chamber 6 is exhausted through the transfer opening 66.

[0055] 2 is a perspective view showing the overall appearance of the holder 7. The holder 7 is configured to include a base ring 71, a connecting portion 72, and a susceptor 74. The base ring 71, the connecting portion 72, and the susceptor 74 are all made of quartz. In other words, the entire holder 7 is made of quartz.

[0056] The base ring 71 is an arc-shaped quartz member with a portion missing from the annular shape. This missing portion is provided to prevent interference between the base ring 71 and a transfer arm 11 of the transfer mechanism 10, which will be described later. The base ring 71 is placed on the bottom surface of the recess 62, and is supported by the wall surface of the chamber 6 (see FIG. 1). A plurality of connecting portions 72 (four in this embodiment) are erected on the upper surface of the base ring 71 along the circumferential direction of the annular shape. The connecting portions 72 are also quartz members, and are fixed to the base ring 71 by welding.

[0057] The susceptor 74 is supported by four connecting portions 72 provided on the base ring 71. FIG.

[0058] The susceptor 74 includes a holding plate 75 and a plurality of support pins 77. The holding plate 75 is a substantially circular, flat member made of quartz. The diameter of the holding plate 75 is larger than the diameter of the semiconductor wafer W, for example. That is, the holding plate 75 has a planar size larger than that of the semiconductor wafer W, for example.

[0059] The upper surface of the holding plate 75 is a flat holding surface 75a. A plurality of support pins 77 are erected on the holding surface 75a of the holding plate 75. In this embodiment, a total of 12 support pins 77 are erected every 30° along a circumference concentric with the outer circumferential circle of the holding surface 75a. The diameter of the circle on which the 12 support pins 77 are arranged (the distance between opposing support pins 77) is smaller than the diameter of the semiconductor wafer W. For example, if the diameter of the semiconductor wafer W is φ300 mm, the diameter is preferably φ270 mm to φ280 mm (φ270 mm in this embodiment). Each support pin 77 is made of quartz. The plurality of support pins 77 may be provided on the upper surface of the holding plate 75 by welding, or may be machined integrally with the holding plate 75.

[0060] Returning to FIG. 2, four connecting portions 72 erected on the base ring 71 are fixed to the peripheral edge of the holding plate 75 of the susceptor 74 by welding. That is, the susceptor 74 and the base ring 71 are fixedly connected by the connecting portions 72. The base ring 71 of the holding portion 7 is supported on the wall surface of the chamber 6, and the holding portion 7 is thereby attached to the chamber 6. When the holding portion 7 is attached to the chamber 6, the holding plate 75 of the susceptor 74 is in a horizontal position (a position in which the normal line coincides with the vertical direction). That is, the holding surface 75a of the holding plate 75 is a horizontal plane.

[0061] The semiconductor wafer W loaded into the chamber 6 is placed and held in a horizontal position on the susceptor 74 of the holder 7 attached to the chamber 6. At this time, the semiconductor wafer W is supported by twelve support pins 77 erected on a holding plate 75 and held on the susceptor 74. More precisely, the upper ends of the twelve support pins 77 contact the underside of the semiconductor wafer W to support the semiconductor wafer W. Because the heights of the twelve support pins 77 (the distances from the upper ends of the support pins 77 to the holding surface 75a of the holding plate 75) are uniform, the semiconductor wafer W can be supported in a horizontal position by the twelve support pins 77. Support Pins Furthermore, the semiconductor wafer W is supported by the plurality of support pins 77 at a predetermined distance from the holding surface 75a of the holding plate 75.

[0062] 2 and 3, an opening 78 is formed in the holding plate 75 of the susceptor 74, penetrating vertically. The opening 78 is provided so that the lower radiation thermometer 20 can receive radiation (infrared light) emitted from the underside of the semiconductor wafer W. That is, the lower radiation thermometer 20 receives the light emitted from the underside of the semiconductor wafer W through the opening 78 and a transparent window 21 attached to the through-hole 61b of the chamber side 61, thereby measuring the temperature of the semiconductor wafer W. The holding plate 75 of the susceptor 74 also has four through-holes 79 formed therein, through which lift pins 12 of the transfer mechanism 10, described later, penetrate to transfer the semiconductor wafer W. The holding plate 75 also has four through-holes 76 formed therein, through which lift pins 12 of the transfer mechanism 10, described later, penetrate to move the quartz plate 100 up and down.

[0063] FIG. 4 is a perspective view showing the quartz plate 100. The quartz plate 100 (see FIG. 4) is placed on the holding surface 75a of the holding plate 75. The quartz plate 100 is formed, for example, in the shape of a circular quartz plate having an outer circumferential circle concentric with the outer circumferential circle of the holding surface 75a of the holding plate 75. Similar to the holding plate 75, the quartz plate 100 has an opening 108 penetrating vertically. The opening 108 is provided so that the lower radiation thermometer 20 can receive radiation (infrared light) emitted from the lower surface of the quartz plate 100. The quartz plate 100 is placed on the holding plate 75 so that the opening 108 is positioned directly above the opening 78. This allows the lower radiation thermometer 20 to receive radiation emitted from the lower surface of the semiconductor wafer W. The quartz plate 100 is also provided with four through holes 109 through which lift pins 12 of the transfer mechanism 10, which will be described later, penetrate to transfer the semiconductor wafer W. The quartz plate 100 is also provided with pin through holes 107 through which support pins 77 erected on the disk-shaped holding surface 75a penetrate.

[0064] The planar size of the quartz plate 100 is, for example, ±20% of the planar size of the semiconductor wafer W. For example, if the diameter of the semiconductor wafer W is φ300 mm, the diameter of the quartz plate 100 is preferably approximately φ240 mm to φ360 mm. As will be described later, the quartz plate 100 cools the semiconductor wafer W by contacting one surface (front surface Wf or back surface Wb) of the semiconductor wafer W. In this embodiment, the quartz plate 100 contacts the back surface of the semiconductor wafer W. When the planar size of the quartz plate 100 is closer to the planar size of the semiconductor wafer W, the entire surface of the semiconductor wafer W is cooled by the quartz plate 100. This improves the cooling efficiency of the semiconductor wafer W by the quartz plate 100. However, the temperature drop rate of the semiconductor wafer W tends to be faster at the edges than at the center. Therefore, even if the quartz plate 100 has a planar size that allows it to contact only the center portion of the semiconductor wafer W, the semiconductor wafer W can be cooled efficiently.

[0065] FIG. 5 is a partial cross-sectional view showing a partial cross section of the quartz plate 100. As shown in FIG. 5, a recess 101 is formed on a surface 100a of the quartz plate 100 that contacts the semiconductor wafer W (hereinafter referred to as the contact surface 100a). For example, a plurality of recesses 101 are formed. Furthermore, the recesses 101 are preferably linear grooves. These linear grooves are formed, for example, parallel to each other. If the surface of the quartz plate 100 is smooth without the recesses 101, the quartz plate 100 and the semiconductor wafer W may be difficult to separate after contacting each other. Therefore, by forming the recesses 101 in the quartz plate 100, a gap exists between the quartz plate 100 and the semiconductor wafer W even when the quartz plate 100 and the semiconductor wafer W are in contact with each other. This prevents adhesion between the quartz plate 100 and the semiconductor wafer W. This gap facilitates separation of the semiconductor wafer W and the quartz plate 100 that are in contact with each other. Therefore, after the semiconductor wafer W is cooled by the quartz plate 100, the quartz plate 100 and the semiconductor wafer W can be smoothly separated from each other.

[0066] 6 is a plan view of the transfer mechanism 10. The transfer mechanism 10 includes two transfer arms 11. The transfer arms 11 are arc-shaped to fit the generally annular recess 62. Two lift pins 12 are provided on each of the transfer arms 11. The transfer arms 11 and the lift pins 12 are made of quartz. Each transfer arm 11 is rotatable by a horizontal movement mechanism 13. The horizontal movement mechanism 13 horizontally moves the transfer arm 11 between a transfer operation position A (position indicated by a solid line in FIG. 6) where the semiconductor wafer W is transferred to and from the holder 7, a cooling operation position B (position indicated by a dashed line in FIG. 6) where the quartz plate 100 (and the semiconductor wafer W) is raised and lowered, and a retracted position C (position indicated by a dashed line in FIG. 6) where the transfer arm 11 does not overlap the semiconductor wafer W held by the holder 7 in a plan view. The horizontal movement mechanism 13 may be one that rotates each transfer arm 11 using an individual motor, or one that uses a link mechanism to rotate a pair of transfer arms 11 in conjunction with one another using a single motor. The retracted position C is directly above the base ring 71 of the holder 7. Since the base ring 71 is placed on the bottom surface of the recess 62, the retracted position C of the transfer arm 11 is inside the recess 62.

[0067] 7 is a side view of the transfer mechanism 10. The transfer mechanism 10 includes a lifting mechanism 14. The lifting mechanism 14 moves the transfer arm 11 and the lift pins 12 in the up and down direction. As shown in FIG. 7, the lifting mechanism 14 raises and lowers the transfer arm 11 to the highest position for transferring the semiconductor wafer W (a height position of the transfer arm 11 corresponding to a transfer position X, which will be described later), the lowest position for performing heat treatment on the semiconductor wafer W (a height position of the transfer arm 11 corresponding to a heating position Y, which will be described later), and a position therebetween where the quartz plate 100 abuts against the back surface Wb of the semiconductor wafer W (a height position of the transfer arm 11 corresponding to a cooling position Z, which will be described later).

[0068] In addition, an exhaust mechanism (not shown) is also provided near the location where the drive part of the transfer mechanism 10 (horizontal movement mechanism 13 and lifting mechanism 14) is located, and is configured to exhaust the atmosphere around the drive part of the transfer mechanism 10 to the outside of the chamber 6.

[0069] Fig. 8 is a flow diagram showing the processing operation in the heat treatment apparatus 1. Figs. 9 to 11 are side views showing the susceptor 74 together with the semiconductor wafer W, the quartz plate 100, and the lift pins 12. Fig. 9 shows the state in which the semiconductor wafer W is placed at the transfer position X, Fig. 10 shows the state in which the semiconductor wafer W is placed at the heating position Y, and Fig. 11 shows the state in which the semiconductor wafer W is placed at the cooling position Z.

[0070] 8 to 11, the specific operation of the heat treatment apparatus 1 will be described below. First, prior to processing of the semiconductor wafer W, the gas supply valve 84 is opened, and the exhaust valve 89 is also opened to start supplying and exhausting gas to and from the chamber 6. When the valve 84 is opened, nitrogen gas is supplied to the heat treatment space 65 through the gas supply hole 81. When the valve 89 is opened, the gas in the chamber 6 is exhausted through the gas exhaust hole 86. As a result, the nitrogen gas supplied from the upper part of the heat treatment space 65 in the chamber 6 flows downward and is exhausted from the lower part of the heat treatment space 65.

[0071] Furthermore, by opening the valve 192, the gas inside the chamber 6 is also exhausted from the transfer opening 66. Furthermore, the atmosphere around the drive unit of the transfer mechanism 10 is also exhausted by an exhaust mechanism (not shown). Note that during the heat treatment of the semiconductor wafer W in the heat treatment apparatus 1, nitrogen gas is continuously supplied to the heat treatment space 65, and the supply amount is changed as appropriate depending on the treatment process.

[0072] Next, gate valve 185 is opened to open transfer opening 66, and a semiconductor wafer W to be processed is carried into heat treatment space 65 in chamber 6 through transfer opening 66 by a transfer robot outside the apparatus. At this time, there is a risk that the atmosphere outside the apparatus may be drawn in as the semiconductor wafer W is carried in, but since nitrogen gas is continuously supplied to chamber 6, the nitrogen gas flows out from transfer opening 66, making it possible to minimize the drawing in of such external atmosphere.

[0073] The semiconductor wafer W carried in by the transfer robot advances to a position directly above the holder 7 and stops there (step S1). Then, the pair of transfer arms 11 of the transfer mechanism 10 move horizontally from the retracted position C (see FIG. 6) to the transfer operation position A (see FIG. 6) and rise, causing the lift pins 12 to pass through the through holes 79 of the susceptor 74 and the through holes 109 of the quartz plate 100 and protrude from the upper surface of the quartz plate 100 to receive the semiconductor wafer W, as shown in FIG. 9. At this time, the lift pins 12 rise above the upper ends of the support pins 77.

[0074] After the semiconductor wafer W is placed on the lift pins 12, the transfer robot exits the heat treatment space 65, and the transfer opening 66 is closed by the gate valve 185. Then, the pair of transfer arms 11 descend, transferring the semiconductor wafer W from the transfer mechanism 10 to the susceptor 74 of the holder 7, where it is held horizontally from below. The semiconductor wafer W is supported by a plurality of support pins 77 erected on the holding plate 75 and held on the susceptor 74. The semiconductor wafer W is held on the holder 7 with its front surface, which is the surface to be processed, facing upward. That is, as shown in FIG. 10 , the semiconductor wafer W moves to the heating position Y (step S2). Here, the position where the semiconductor wafer W is held on the holder 7 is referred to as the heating position Y (see FIGS. 8 and 10 ). A predetermined gap is formed between the back surface Wb (the main surface opposite to the front surface Wf) of the semiconductor wafer W supported by the plurality of support pins 77 and the holding surface 75a of the holding plate 75. The pair of transfer arms 11 that have been lowered to below the susceptor 74 are retracted to the retracted position C, that is, inside the recessed portion 62, by the horizontal movement mechanism 13.

[0075] After the semiconductor wafer W is held horizontally from below by the susceptor 74 of the holder 7, which is made of quartz, the 40 halogen lamps HL of the halogen heating unit 4 are simultaneously turned on to begin preheating (assisted heating) (preheating step) (step S3). Halogen light emitted from the halogen lamps HL passes through the lower chamber window 64, susceptor 74, and quartz plate 100, all of which are made of quartz, and is irradiated onto the underside of the semiconductor wafer W. The semiconductor wafer W is preheated by being irradiated with light from the halogen lamps HL, and its temperature rises. Note that 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.

[0076] The temperature of the semiconductor wafer W, which is heated by the light irradiation from the halogen lamps HL, is measured by the lower radiation thermometer 20. The measured temperature of the semiconductor wafer W is transmitted to the control unit 3. The control unit 3 controls the output of the halogen lamps HL while monitoring whether the temperature of the semiconductor wafer W, which is heated by the light irradiation from the halogen lamps HL, has reached a predetermined preheating temperature T1. In other words, the control unit 3 feedback-controls the output of the halogen lamps HL based on the value measured by the lower radiation thermometer 20 so that the temperature of the semiconductor wafer W becomes the preheating temperature T1.

[0077] After the temperature of the semiconductor wafer W reaches the preheating temperature T1, the control unit 3 temporarily maintains the semiconductor wafer W at the preheating temperature T1. Specifically, when the temperature of the semiconductor wafer W measured by the lower radiation thermometer 20 reaches the preheating temperature T1, the control unit 3 adjusts the output of the halogen lamps HL to maintain the temperature of the semiconductor wafer W at approximately the preheating temperature T1.

[0078] By performing preheating using the halogen lamps HL in this manner, the temperature of the entire semiconductor wafer W is uniformly raised to the preheating temperature T1. During preheating using the halogen lamps HL, the temperature of the peripheral portion of the semiconductor wafer W, where heat dissipation is more likely, tends to be lower than that of the central portion, but the arrangement density of the halogen lamps HL in the halogen heating unit 4 is higher in the region facing the peripheral portion of the semiconductor wafer W than in the region facing the central portion. As a result, a greater amount of light is irradiated onto the peripheral portion of the semiconductor wafer W, where heat dissipation is more likely, and the in-plane temperature distribution of the semiconductor wafer W during the preheating stage can be made uniform.

[0079] When a predetermined time has elapsed since the temperature of the semiconductor wafer W reached the preheating temperature T1, the flash lamps FL of the flash heating unit 5 irradiate the surface of the semiconductor wafer W held on the susceptor 74 with flash light. At this time, part of the flash light emitted from the flash lamps FL heads directly into the chamber 6, and the other part is reflected by the reflector 52 before heading into the chamber 6, and the semiconductor wafer W is flash-heated by the irradiation of these flash lights (main heating step) (step S4).

[0080] Flash heating is performed by irradiating a flash of light (flash of light) from flash lamps FL, which allows the surface temperature of the semiconductor wafer W to rise in a short time. That is, the flash of light irradiated from the flash lamps FL is an extremely short, intense flash of light with an irradiation time (flash light irradiation time) of approximately 0.1 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 flash-heated by the irradiation of the flash of light from the flash lamps FL instantaneously rises to a processing temperature T2 of 1,000°C or higher and then rapidly drops.

[0081] After the flash heating process is completed and a predetermined time has elapsed, the halogen lamps HL are turned off. This causes the temperature of the semiconductor wafer W to rapidly drop from the preheating temperature T1. The temperature of the semiconductor wafer W during this drop is measured by the lower radiation thermometer 20, and the measurement results are transmitted to the control unit 3. The control unit 3 monitors, based on the measurement results of the lower radiation thermometer 20, whether the temperature of the semiconductor wafer W has dropped to the predetermined temperature.

[0082] Furthermore, the control unit 3 brings the quartz plate 100 into contact with the semiconductor wafer W after a predetermined time t1 has elapsed since the semiconductor wafer W reached its maximum temperature (processing temperature T2) due to the irradiation of flash light from the flash lamps FL (step S5). Here, the predetermined time t1 is, for example, 0.1 to 3 seconds. By setting such a predetermined time, the temperature of the semiconductor wafer W can be quickly lowered.

[0083] The quartz plate 100 is moved by the lifting mechanism 14. Specifically, when the lifting mechanism 14 raises the pair of transfer arms 11 at the cooling operation position B (see FIGS. 6 and 11), a total of four lift pins 12 pass through the through holes 76 (see FIG. 2) formed in the susceptor 74. The upper ends of the lift pins 12 then protrude from the upper surface of the susceptor 74. As shown in FIG. 11, the upper ends of the lift pins 12 protruding from the upper surface of the susceptor 74 place the quartz plate 100 on them and move the quartz plate 100 upward. The quartz plate 100, moved upward by the lift pins 12, comes into contact with the back surface Wb of the semiconductor wafer W supported by the support pins 77. The quartz plate 100, which has come into contact with the semiconductor wafer W due to the lifting of the upper ends of the lift pins 12, continues to move upward even after the semiconductor wafer W is placed thereon due to further lifting of the upper ends of the lift pins 12. The lifting mechanism 14 positions the semiconductor wafer W and the quartz plate 100 at a position furthest from the susceptor 74 and stops the movement. At this time, the back surface Wb of the semiconductor wafer W comes into contact with the quartz plate 100, and the semiconductor wafer W is cooled by the quartz plate 100. That is, the semiconductor wafer W moves to the cooling position Z shown in FIG. 11 (cooling step) (step S6). Note that the height position of the quartz plate 100 from the time the quartz plate 100 comes into contact with the back surface Wb of the semiconductor wafer W until the semiconductor wafer W rises to the cooling position Z is the contact position between the quartz plate 100 and the semiconductor wafer W.

[0084] After the semiconductor wafer W has cooled to a predetermined temperature or below, the lifting mechanism 14 lowers the semiconductor wafer W and the quartz plate 100. Then, as shown in FIG. 10, the semiconductor wafer W moves again to the heating position Y (step S7). Specifically, the lifting mechanism 14 lowers the pair of transfer arms 11 from the cooling operation position B to remove the lift pins 12 from the through holes 76. At this time, the semiconductor wafer W is placed on the upper ends of the support pins 77. The quartz plate 100 is then placed on the susceptor 74. In this manner, the semiconductor wafer W and the quartz plate 100 are spaced apart from each other. Note that the height position of the quartz plate 100 from the time when it leaves the back surface Wb of the semiconductor wafer W until the time when the quartz plate 100 is placed on the susceptor 74 is the separation position between the quartz plate 100 and the semiconductor wafer W.

[0085] Then, the transfer arm 11 moves horizontally and upward to the transfer operation position A, causing the lift pins 12 to protrude from the through-holes 79 formed in the susceptor 74 and the through-holes 109 formed in the quartz plate 100, thereby moving the heat-treated semiconductor wafer W upward. As a result, the semiconductor wafer W moves to the transfer position X (step S8).

[0086] Thereafter, the transport opening 66, which had been closed by the gate valve 185, is opened, and the semiconductor wafer W placed on the lift pins 12 is transported out of the chamber 6 by a transport robot outside the apparatus, completing the heat treatment of the semiconductor wafer W.

[0087] As described above, the lifting mechanism 14 moves the quartz plate 100 up and down relative to the semiconductor wafer W between a contact position where the quartz plate 100 contacts the back surface Wb of the semiconductor wafer W and a spaced position where the quartz plate 100 is spaced apart from the semiconductor wafer W. In other words, the semiconductor wafer W and the quartz plate 100 are moved relatively between the spaced position and the contact position.

[0088] 12 is a graph showing the temperature change over time of the semiconductor wafer W in the heat treatment apparatus 1 of this embodiment. Note that the dotted line in FIG. 12 indicates, for comparison, the temperature change over time of the semiconductor wafer W when cooled naturally without using the quartz plate 100.

[0089] In FIG. 12 , point O indicates the time when the semiconductor wafer W reaches its maximum temperature, and point P indicates the time when the semiconductor wafer W and the quartz plate 100 come into contact. As shown in FIG. 12 , when the semiconductor wafer W comes into contact with the quartz plate 100 after reaching its maximum temperature, the temperature drop rate after contact with the quartz plate 100 is faster than when the semiconductor wafer W does not come into contact with the quartz plate 100. In this embodiment, the semiconductor wafer W comes into contact with the quartz plate 100 immediately after the semiconductor wafer W reaches its maximum temperature, thereby increasing the temperature drop rate of the semiconductor wafer W after heat treatment. This is expected to prevent the inactivation of impurities in an active state in the semiconductor wafer W. This effect is particularly pronounced when the semiconductor wafer W comes into contact with the quartz plate 100 between 0.1 and 3 seconds after the semiconductor wafer W reaches its maximum temperature.

[0090] <Modification 1 of the First Embodiment> A heat treatment apparatus according to Modification 1 of the first embodiment will be described below. FIG. 13 is a side view showing a susceptor 274 according to Modification 1 of the first embodiment, together with a semiconductor wafer W, a quartz plate 100, and lift pins 12. The heat treatment apparatus according to Modification 1 includes a susceptor 274 instead of the susceptor 74. The susceptor 274 includes a holding plate 275 and multiple support pins 77. The holding plate 275 has a hollow portion 279 formed inside the positions where the support pins 77 are erected. The formation of this hollow portion 279 eliminates the need for multiple through holes 79, as in the holding plate 75 of the first embodiment. In other words, the formation of a single hollow portion 279 allows the lift pins 12 to pass through the hollow portion 279 and move the semiconductor wafer W or the quartz plate 100 upward, whether at the transfer operation position A or the cooling operation position B. The heat treatment apparatus according to Modification 1 of the first embodiment allows the configuration of the holding plate 75 to be simplified.

[0091] <Modification 2 of the First Embodiment> A heat treatment apparatus according to Modification 2 of the first embodiment will be described below. FIG. 14 is a side view showing a susceptor 374 according to Modification 2 of the first embodiment together with a semiconductor wafer W, a quartz plate 300, and lift pins 12. The heat treatment apparatus according to Modification 2 includes a susceptor 374 instead of the susceptor 74. The susceptor 374 includes a holding plate 375 and a plurality of support pins 77. The holding plate 375 does not have through holes 76 formed therein. In addition, a quartz plate holder 376 is provided upright on the susceptor 374. The quartz plate 300 is held by the quartz plate holder 376 above the semiconductor wafer W (on the flash heating unit 5 side). There is no need to form through holes for the lift pins or the support pins 77 in the quartz plate 300.

[0092] When the semiconductor wafer W and the quartz plate 300 are brought into contact with each other using the heat treatment apparatus according to Modification 2, first, the lift pins 12 are passed through the through holes 79 by the lifting mechanism 14. Then, as the lift pins 12 are further moved upward, the semiconductor wafer W is placed on the lift pins 12 and moves upward. Then, as the surface of the semiconductor wafer W comes into contact with the quartz plate 300, the semiconductor wafer W is cooled by the quartz plate 300. This allows the configuration of the quartz plate 300 and the holding plate 375 to be simplified.

[0093] <Modification 3 of the First Embodiment> A heat treatment apparatus according to Modification 3 of the first embodiment will be described below. FIG. 15 is a side view showing a susceptor 474 according to Modification 3 of the first embodiment, together with a semiconductor wafer W, a quartz plate 400, and lift pins 12. The heat treatment apparatus according to Modification 3 includes a susceptor 474 instead of the susceptor 374 of Modification 2. The heat treatment apparatus according to Modification 3 includes a quartz plate holder 460 instead of the quartz plate holder 376 of Modification 2. Therefore, the quartz plate holder 376 is not provided upright on the susceptor 474. The quartz plate holder 460 is fixed to the chamber side portion 61. The quartz plate 400 is held above the semiconductor wafer W by the quartz plate holder 460. The heat treatment apparatus according to Modification 3 also simplifies the configuration of the quartz plate 400 and the holding plate 375.

[0094] Second Embodiment The heat treatment apparatus 2 according to the second embodiment will now be described. Fig. 16 is a longitudinal cross-sectional view showing the configuration of the heat treatment apparatus 2 according to the present invention. The heat treatment apparatus 2 in Fig. 16 is a flash lamp annealing apparatus that heats a disk-shaped semiconductor wafer W as a substrate by irradiating the semiconductor wafer W with flash light.

[0095] The heat treatment apparatus 2 includes a flash heating section 250 instead of the flash heating section 5 in the heat treatment apparatus 1. Moreover, the heat treatment apparatus 2 does not include the halogen heating section 4 in the heat treatment apparatus 1. In the description of the second embodiment, the same components as those described in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0096] The flash heating unit 250, located above the chamber 6, is configured with a light source consisting of multiple flash lamps FL inside a housing 51 and a reflector 52 arranged to cover the light source. Sixty flash lamps FL are arranged, for example, in two rows, upper and lower (see FIG. 16). Thirty flash lamps FL(D) are arranged in the lower row, which is closer to the holder 7, and thirty flash lamps FL(U) are also arranged in the upper row, which is farther from the holder 7 than the lower row. The thirty flash lamps FL on both the upper and lower rows are arranged so that their longitudinal directions are parallel to each other along the main surface of the semiconductor wafer W held by the holder 7 (i.e., along the horizontal direction). Therefore, the plane formed by the arrangement of the flash lamps FL(U) and FL(D) on both the upper and lower rows is a horizontal plane. The flash lamps FL(U) function as the first flash light irradiator, and the flash lamps FL(D) function as the second flash light irradiator.

[0097] The flash lamps FL(U) and FL(D) in the second embodiment also emit flashes of light for an extremely short irradiation time of 0.1 to 100 milliseconds, similar to the flash lamps FL in the first embodiment.

[0098] In the preheating step of the second embodiment, the flash lamps FL(U) irradiate the semiconductor wafer W held by the holder 7 with flash light to raise the surface temperature of the semiconductor wafer W from room temperature to a preheating temperature T1. Subsequently, in the main heating step, the flash lamps FL(D) irradiate the semiconductor wafer W, whose temperature has been raised to the preheating temperature T1, with flash light to raise the surface temperature of the semiconductor wafer W to a processing temperature T2 higher than the preheating temperature T1. Note that the flash lamps FL (first flash lamps) that raise the temperature to the preheating temperature T1 may be the flash lamps FL(D). The flash lamps FL (second flash lamps) that raise the temperature to the processing temperature T2 are different from the first flash lamps.

[0099] FIG. 17 is a flow diagram showing the flow of heat treatment of a semiconductor wafer W by the heat treatment apparatus 2 of the second embodiment.

[0100] 16 and 17, a specific operation of the heat treatment apparatus 2 will be described. First, the semiconductor wafer W is carried into the heat treatment space 65 in the chamber 6 in the same manner as in the first embodiment.

[0101] The semiconductor wafer W carried in by the transfer robot advances to a position directly above the holder 7 and stops there (step S11). Then, the pair of transfer arms 11 of the transfer mechanism 10 operate to place the semiconductor wafer W on the lift pins 12, after which the transfer robot retreats from the heat treatment space 65, and the transfer opening 66 is closed by the gate valve 185. Then, the pair of transfer arms 11 descend, and the semiconductor wafer W is transferred from the transfer mechanism 10 to the susceptor 74 of the holder 7, where it is held from below in a horizontal position. The semiconductor wafer W is supported by a plurality of support pins 77 erected on a holding plate 75 and held on the susceptor 74. The semiconductor wafer W is held on the holder 7 with the surface to be processed facing up. That is, the semiconductor wafer W moves to the heating position Y (step S12).

[0102] After the semiconductor wafer W is held from below in a horizontal position by the susceptor 74 of the holder 7 made of quartz, the first flash lamps are all turned on simultaneously to start preheating (assisted heating) (first flash light irradiation step) (step S13). The semiconductor wafer W is preheated by being irradiated with light from the first flash lamps, and the surface temperature rises from room temperature to a preheating temperature T1. The preheating temperature T1 at this time is, for example, 700°C.

[0103] After the surface temperature of the semiconductor wafer W reaches the preheating temperature T1, the second flash lamps are all turned on at once to start main heating (second flash light irradiation step) (step S14). By receiving light irradiation from the second flash lamps, the surface temperature of the semiconductor wafer W is raised from the preheating temperature T1 to a higher processing temperature T2. Here, it is preferable that the interval t2 between when the first flash lamp emits light and when the second flash lamp emits light is within one second. This is because heating by light irradiation from the flash lamps raises the temperature only of the surface portion of the semiconductor wafer W, and if the interval between when the first flash lamp emits light and when the second flash lamp emits light is long, the temperature of the semiconductor wafer W will drop rapidly.

[0104] After the heating by the light irradiation from the first flash lamp and the second flash lamp is completed, the lift pins 12 of the transfer arm 11 move the semiconductor wafer W upward. This moves the semiconductor wafer W to the transfer position X (step S15). Thereafter, the semiconductor wafer W is carried out of the heat treatment apparatus 2 by the transfer robot.

[0105] As described above, according to the heat treatment apparatus 2 of the second embodiment, the temperature is raised both to the preheating temperature and to the treatment temperature by flash light irradiation, so that it is possible to raise the temperature of only the front surface of the semiconductor wafer W without substantially raising the temperature of the back surface of the semiconductor wafer W. As a result, after the flash light irradiation is completed, rapid heat conduction occurs from the front surface to the back surface of the semiconductor wafer W, which can accelerate the rate at which the temperature of the semiconductor wafer W drops after the heat treatment. This makes it possible to prevent the inactivation of impurities activated by the flash light irradiation.

[0106] As described above, by using the heat treatment apparatus 2 to raise the temperature only in a portion relatively shallow from the surface of the semiconductor wafer W, it is expected that the inactivation of impurities in an active state in the semiconductor wafer W can be prevented. Furthermore, the heat treatment apparatus 2 does not require the halogen heating unit 4 in the first embodiment as a heat source for preheating, and therefore the configuration of the apparatus is simplified.

[0107] <Other> In the first embodiment, the flash heating unit 5 is provided with 30 flash lamps FL, but this is not limited to this and the number of flash lamps FL can be any number. Furthermore, the flash lamps FL are not limited to xenon flash lamps and may be krypton flash lamps. Furthermore, the number of halogen lamps HL provided in the halogen heating unit 4 is not limited to 40 and can be any number. Furthermore, in the second embodiment, the number of flash lamps is not limited to 60 divided into two rows, upper and lower. The number of flash lamps in the second embodiment can also be changed as appropriate.

[0108] Furthermore, in the first embodiment described above, the semiconductor wafer W is preheated using a filament-type halogen lamp HL as a continuously lit lamp that emits light continuously for one second or more, but this is not limited to this, and preheating may be performed using a discharge arc lamp (e.g., a xenon arc lamp) or an LED lamp as a continuously lit lamp instead of the halogen lamp HL.

[0109] Furthermore, in the first embodiment, linear groove recesses 101 are formed in the quartz plate 100 (300, 400), but this is not limited to linear grooves. Furthermore, this is not limited to recesses 101, and any structure that creates a gap between the semiconductor wafer W and the surface that contacts the semiconductor wafer W may be used. Therefore, protrusions may be used instead of recesses.

[0110] In the first embodiment, the quartz plate 100 (300, 400) is formed in a disk shape, but is not limited to this shape. In addition to the disk shape, various other shapes such as a triangle shape or a square shape may also be used.

[0111] In the second embodiment, the flash lamps FL are arranged in two rows, one above the other, but this is not limiting. The first and second flash lamps may be arranged on the same plane. Furthermore, the first and second flash lamps may be configured as the same flash lamp, as long as preliminary heating by the first flash lamps and main heating by the second flash lamps can be realized.

[0112] Furthermore, the substrates to be processed by the heat treatment apparatuses 1 and 2 are not limited to semiconductor wafers, but may also be glass substrates used in flat panel displays such as liquid crystal display devices, or substrates for solar cells. [Explanation of symbols]

[0113] 1,2 Heat treatment equipment 3. Control Unit 4 Halogen heating section 5,250 Flash heating section 6 chambers 7 Holding part 10 Transfer mechanism 11 Transfer arm 12 lift pins 13 Horizontal movement mechanism 14 Lifting mechanism 20 Lower radiation thermometer 25 Upper radiation thermometer 43 Reflector 52 Reflector 63 Upper chamber window 64 Lower chamber window 65 Heat Treatment Space 71 Base Ring 72 Connecting part 74,374,474 susceptors 75,275,375 Retaining Plate 75a Holding surface 76 Through Hole 77 Support pin 78 Opening 79,279 through holes 100,300,400 Quartz plate 100a Contact surface 101 Recess 107,109 Through holes 108 Opening 376 Quartz plate holding part 460 Quartz plate holding part FL flash lamp HL halogen lamp W Semiconductor wafer Wf: Surface of semiconductor wafer Wb Backside of semiconductor wafer

Claims

1. A heat treatment apparatus that heats a substrate by irradiating the substrate with light, a chamber for accommodating the substrate; a holder that holds the substrate within the chamber; a light irradiation unit that heats the substrate held by the holder by irradiating the substrate with a flash of light obtained by converting electrostatic energy previously stored in a capacitor into a light pulse of 0.1 millisecond to 100 milliseconds; a quartz plate for cooling the substrate after it has been heated by the light irradiation unit; a moving mechanism that relatively moves the quartz plate or the substrate between a contact position where the quartz plate contacts the front or back surface of the substrate and a separation position where the quartz plate is separated from the substrate; a control unit that controls the operation of the movement mechanism; Equipped with The heat treatment apparatus is characterized in that the control unit controls the movement mechanism so that the quartz plate or the substrate moves to the abutment position 0.1 to 3 seconds after the substrate reaches its maximum temperature due to flash irradiation from the light irradiation unit.

2. 2. The heat treatment apparatus according to claim 1, 10. A heat treatment apparatus according to claim 9, wherein the planar size of the quartz plate is within ±20% of the planar size of the substrate.

3. 3. The heat treatment apparatus according to claim 1, A heat treatment apparatus characterized in that a recess or a protrusion is formed on the surface of the quartz plate that comes into contact with the substrate.

4. 4. The heat treatment apparatus according to claim 3, The heat treatment apparatus is characterized in that the recessed portion is a linear groove.

5. A heat treatment method for heating a substrate by irradiating the substrate with light, comprising: a heating step of heating the substrate held by a holder in a chamber that accommodates the substrate by irradiating the substrate with a flash of light in which electrostatic energy previously stored in a capacitor is converted into a light pulse of 0.1 milliseconds to 100 milliseconds; a cooling step of moving a quartz plate relative to the heated substrate after the heating step, and bringing the quartz plate into contact with the front or back surface of the substrate to cool the substrate; Equipped with The heat treatment method is characterized in that in the cooling step, the substrate and the quartz plate are brought into contact with each other 0.1 to 3 seconds after the substrate reaches its maximum temperature due to flash irradiation.

Images