JP2011077147A - Heat treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat treatment apparatus capable of prohibiting a temperature decrease in a through-hole part for a supporting pin and equalizing a heat treatment of a substrate. <P>SOLUTION: A hot plate 71 and a susceptor 72 are provided with a through-hole 77 for the supporting pin 70, and a cylindrical pin hole sleeve 78 is inserted in the through-hole 77. The pin hole sleeve 78 has a height in a range of ±0.2 mm with respect to a susceptor surface and a thickness in a range of 0.5-10 mm corresponding to a shape of the susceptor 72. The pin hole sleeve 78 is inserted with a margin of about 1 mm with respect to the through-hole 77. In a case where the susceptor 72 is made of quartz, by using a material with a thermal conductivity higher than that of quartz, such as ALN and SiC, a temperature of a part corresponding to the through-hole 77 can be set higher than the case of quartz. As a result, the temperature decrease in the part of the through-hole 77 for the supporting pin 70 can be prevented. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a heat treatment apparatus for heating a substrate by irradiating light onto a substrate such as a semiconductor wafer or a glass substrate (hereinafter simply referred to as “substrate”).

Conventionally, a lamp annealing apparatus using a halogen lamp has been generally used in an ion activation process of a semiconductor wafer after ion implantation. In such a lamp annealing apparatus, ion activation of a semiconductor wafer is performed by heating (annealing) the semiconductor wafer to a temperature of about 1000 to 1100 degrees Celsius, for example. In such a heat treatment apparatus, the temperature of the substrate is raised at a speed of about several hundred degrees per second by using the energy of light irradiated by the halogen lamp.

  On the other hand, in recent years, as semiconductor devices have been highly integrated, it is desired to reduce the junction depth as the gate length becomes shorter. However, even when ion activation of a semiconductor wafer is performed using a lamp annealing apparatus that raises the temperature of the semiconductor wafer at a speed of about several hundred degrees per second, ions such as boron and phosphorus implanted in the semiconductor wafer are heated by heat. It has been found that the phenomenon of deep diffusion occurs. When such a phenomenon occurs, there is a concern that the junction depth becomes deeper than required, which hinders good device formation.

  For this reason, the surface of the semiconductor wafer into which ions are implanted by irradiating the surface of the semiconductor wafer with flash light using a xenon flash lamp (hereinafter simply referred to as “flash lamp” means xenon flash lamp). Has been proposed that raises the temperature only for a very short time (several milliseconds or less). 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 almost coincides with the fundamental absorption band of a silicon semiconductor wafer. Therefore, when the semiconductor wafer is irradiated with flash light from the xenon flash lamp, the semiconductor wafer can be rapidly heated with little transmitted light. In addition, it has been found that the temperature of only the vicinity of the surface of the semiconductor wafer can be selectively raised by flash irradiation for a very short time of several milliseconds or less. For this reason, if the temperature is raised for a very short time by a xenon flash lamp, only the ion activation can be performed without diffusing ions deeply.

  As a heat treatment apparatus using such a xenon flash lamp, in Patent Documents 1, 2, and 3, a pulse light emitting lamp such as a flash lamp is disposed on the front surface side of a semiconductor wafer, and a continuous lighting lamp such as a halogen lamp is disposed on the back surface side. Are arranged and a desired heat treatment is performed by a combination thereof. In the heat treatment apparatuses disclosed in Patent Documents 1, 2, and 3, the temperature of the semiconductor wafer is raised to a certain temperature by a halogen lamp or the like, and then raised to a desired processing temperature by pulse heating from a flash lamp.

  In such a conventional heat treatment apparatus, in order to prevent contamination of the semiconductor wafer, a quartz susceptor is disposed between the heater and the semiconductor wafer. When the wafer is placed on the heater, it is necessary to lift up the semiconductor wafer by using pins or the like, so that through holes for pins are formed in the heater and the quartz susceptor.

JP 2009-004410 A JP 2009-070948 A JP 2009-004427 A

  However, as in the heat treatment devices disclosed in Patent Documents 1, 2, and 3, when a through hole for a pin is formed in the heater and the quartz susceptor, the temperature of the through hole portion is reduced. There is a problem that non-uniform heat treatment is performed on the semiconductor wafer.

  This invention is made | formed in view of the said subject, and it aims at providing the heat processing apparatus which suppresses the temperature fall of the through-hole part for support pins, and can equalize the heat processing of a board | substrate.

  In order to solve the above-described problem, the invention described in claim 1 is a heat treatment apparatus for heating a substrate by irradiating the substrate with light, a hot plate for preheating the substrate, and a substrate mounted on the hot plate. A substrate holding unit that holds and holds the substrate in a horizontal position, a light irradiation unit that emits light to the substrate supported by the substrate support unit, and the substrate holding while supporting the substrate. A support pin that raises and lowers the substrate relative to a portion, and a through hole that penetrates the hot plate and the susceptor for the support pin, and the through hole has a material having higher thermal conductivity than the susceptor. The pin hole sleeve is formed.

  The invention according to claim 2 is the heat treatment apparatus according to claim 1, wherein the material forming the pin hole sleeve is formed of any one of ALN, SiC, alumina, carbon, and silicon. It is characterized by being.

  Furthermore, the invention according to claim 3 is the heat treatment apparatus according to claim 1 or 2, wherein the pin hole sleeve is fitted into the through hole.

  According to the heat treatment apparatus of the present invention, a pin hole sleeve, which is a material having a higher thermal conductivity than the susceptor, is formed in the through hole penetrating the hot plate and the susceptor for the support pin. Therefore, there is an effect that the temperature reduction of the through hole portion for the support pin can be suppressed and the heat treatment of the substrate can be made uniform.

It is a longitudinal cross-sectional view which shows the structure of the heat processing apparatus which concerns on this invention. It is sectional drawing which cut | disconnected the chamber in the horizontal surface in the position of the gas introduction buffer. It is sectional drawing which shows the structure of a board | substrate holding part. It is a top view which shows a hot plate. It is a graph which shows the temperature difference with the target temperature in a through-hole and its periphery.

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

  The overall configuration of the heat treatment apparatus according to the present invention will be outlined. FIG. 1 is a longitudinal sectional view showing a configuration of a heat treatment apparatus 1 according to the present invention. The heat treatment apparatus 1 is a flash lamp annealing apparatus that irradiates the surface of a substantially circular semiconductor wafer W as a substrate with flash light and heats the semiconductor wafer W.

  The heat treatment apparatus 1 includes a substantially cylindrical chamber 6 that accommodates a semiconductor wafer W, and a lamp house 5 that houses a plurality of flash lamps FL. Further, the heat treatment apparatus 1 includes a control unit 3 that controls each operation mechanism provided in the chamber 6 and the lamp house 5 to execute the heat treatment of the semiconductor wafer W.

  The chamber 6 is provided below the lamp house 5 and includes a chamber side 63 having a substantially cylindrical inner wall and a chamber bottom 62 covering the lower part of the chamber side 63. A space surrounded by the chamber side 63 and the chamber bottom 62 is defined as a heat treatment space 65. An upper opening 60 is formed above the heat treatment space 65, and a chamber window 61 is attached to the upper opening 60 to be closed.

  The chamber window 61 constituting the ceiling portion of the chamber 6 is a disk-shaped member made of quartz, and functions as a quartz window that transmits the flash light emitted from the lamp house 5 to the heat treatment space 65. The chamber bottom 62 and the chamber side 63 constituting the main body of the chamber 6 are formed of, for example, a metal material having excellent strength and heat resistance such as stainless steel, and a ring on the upper side of the inner side surface of the chamber side 63. 631 is formed of an aluminum (Al) alloy or the like having durability superior to stainless steel against deterioration due to flash light irradiation.

  Further, in order to maintain the airtightness of the heat treatment space 65, the chamber window 61 and the chamber side portion 63 are sealed by an O-ring. That is, the O-ring is sandwiched between the lower surface peripheral portion of the chamber window 61 and the chamber side portion 63, the clamp ring 90 is brought into contact with the upper peripheral portion of the chamber window 61, and the clamp ring 90 is attached to the chamber side portion 63. The chamber window 61 is pressed against the O-ring by screwing.

  The chamber bottom 62 has a plurality of (this embodiment) for supporting the semiconductor wafer W from the lower surface (the surface opposite to the side irradiated with the flash light from the lamp house 5) through the substrate holding portion 7. In the embodiment, three support pins 70 are erected. The support pin 70 is made of, for example, quartz and is fixed from the outside of the chamber 6 and can be easily replaced.

The chamber side portion 63 has a transfer opening 66 for loading and unloading the semiconductor wafer W, and the transfer opening 66 can be opened and closed by a gate valve 185 that rotates about a shaft 662. In a portion of the chamber side 63 opposite to the transfer opening 66, an inert gas such as nitrogen (N ₂ ) gas, helium (He) gas, or argon (Ar) gas is provided in the heat treatment space 65, Alternatively, an introduction path 81 for introducing oxygen (0 ₂ ) gas or the like is formed, one end of which is connected to an air supply mechanism (not shown) via a valve 82, and the other end is formed inside the chamber side portion 63. Connected to the gas introduction buffer 83. A discharge passage 86 for discharging the gas in the heat treatment space 65 is formed in the transfer opening 66 and is connected to an exhaust mechanism (not shown) via a valve 87.

  FIG. 2 is a cross-sectional view of the chamber 6 cut along a horizontal plane at the position of the gas introduction buffer 83. As shown in FIG. 2, the gas introduction buffer 83 is formed over about ３ of the inner periphery of the chamber side 63 on the opposite side of the transfer opening 66 shown in FIG. Then, the processing gas guided to the gas introduction buffer 83 is supplied into the heat treatment space 65 from the plurality of gas supply holes 84.

  The heat treatment apparatus 1 also includes a substantially disk-shaped substrate holding unit 7 that holds the semiconductor wafer W in a horizontal position inside the chamber 6 and performs preheating of the held semiconductor wafer W before irradiation with flash light. A substrate holding unit elevating mechanism 4 for elevating the substrate holding unit 7 with respect to the chamber bottom 62 which is the bottom surface of the chamber 6. 1 includes a substantially cylindrical shaft 41, a moving plate 42, guide members 43 (three are arranged around the shaft 41 in the present embodiment), a fixed plate 44, and a ball screw 45. And a nut 46 and a motor 40. A substantially circular lower opening 64 having a smaller diameter than that of the substrate holding portion 7 is formed in the chamber bottom 62 which is the lower portion of the chamber 6, and the stainless steel shaft 41 is inserted through the lower opening 64 to form a substrate. The substrate holding unit 7 is supported by being connected to the lower surface of the holding unit 7 (strictly, the hot plate 71 of the substrate holding unit 7).

  A nut 46 that is screwed into the ball screw 45 is fixed to the moving plate 42. The moving plate 42 is slidably guided by a guide member 43 that is fixed to the chamber bottom 62 and extends downward, and is movable in the vertical direction. Further, the moving plate 42 is connected to the substrate holding unit 7 through the shaft 41.

  The motor 40 is installed on a fixed plate 44 attached to the lower end of the guide member 43, and is connected to the ball screw 45 via the timing belt 401. When the substrate holding part 7 is raised and lowered by the substrate holding part raising / lowering mechanism 4, the motor 40 as a driving part rotates the ball screw 45 under the control of the control part 3, and the moving plate 42 to which the nut 46 is fixed is the guide member 43. Along the vertical direction. As a result, the shaft 41 fixed to the moving plate 42 moves along the vertical direction, and the substrate holding part 7 connected to the shaft 41 moves to the delivery position of the semiconductor wafer W shown in FIG. Ascend and descend smoothly.

  On the upper surface of the moving plate 42, a mechanical stopper 451 having a substantially semi-cylindrical shape (a shape obtained by cutting the cylinder in half along the longitudinal direction) is provided so as to extend along the ball screw 45. If the upper limit of the mechanical stopper 451 is struck against the end plate 452 provided at the end of the ball screw 45, the moving plate 42 is prevented from rising abnormally. Thereby, the substrate holding part 7 does not rise above a predetermined position below the chamber window 61, and the collision between the substrate holding part 7 and the chamber window 61 is prevented.

  Further, the substrate holding unit elevating mechanism 4 has a manual elevating unit 49 that manually elevates and lowers the substrate holding unit 7 when performing maintenance inside the chamber 6. The manual elevating part 49 has a handle 491 and a rotation shaft 492. By rotating the rotation shaft 492 via the handle 491, the ball screw 45 connected to the rotation shaft 492 is rotated via the timing belt 495 to hold the substrate. The part 7 can be raised and lowered.

  A telescopic bellows 47 that surrounds the shaft 41 and extends downward is provided below the chamber bottom 62, and its upper end is connected to the lower surface of the chamber bottom 62. On the other hand, the lower end of the bellows 47 is attached to the bellows lower end plate 471. The bellows lower end plate 471 is attached by being screwed to the shaft 41 by a hook-like member 411. The bellows 47 is contracted when the substrate holder 7 is raised relative to the chamber bottom 62 by the substrate holder lifting mechanism 4, and the bellows 47 is expanded when it is lowered. Even when the substrate holder 7 moves up and down, the bellows 47 expands and contracts to maintain the airtight state in the heat treatment space 65.

  FIG. 3 is a cross-sectional view illustrating a configuration of the substrate holding unit 7. The substrate holding unit 7 includes a hot plate (heating plate) 71 for preheating (so-called assist heating) the semiconductor wafer W before the flash light irradiation, and an upper surface of the hot plate 71 (the substrate holding unit 7 holds the semiconductor wafer W). And a susceptor 72 placed on the side surface. As described above, the shaft 41 that moves up and down the substrate holding unit 7 is connected to the lower surface of the substrate holding unit 7 (see FIG. 1).

  The susceptor 72 is made of quartz. The susceptor 72 made of quartz is placed on the hot plate 71 with its lower surface in contact with the upper surface of the hot plate 71. Further, a concave portion 176 having a tapered periphery is formed on the upper surface of the susceptor 72, and the semiconductor wafer W is placed in the concave portion 176 (the bottom surface of the concave portion 176). Further, a pin 75 that prevents the semiconductor wafer W from being displaced is provided on the upper surface of the susceptor 72 and outside the recess 176. The pin 75 may be formed of pyrolytic boron nitride or may be formed of quartz.

  The hot plate 71 includes an upper plate 73 and a lower plate 74 made of stainless steel. A resistance heating wire 76 such as a nichrome wire for heating the hot plate 71 is disposed between the upper plate 73 and the lower plate 74, and is filled with a conductive nickel (Ni) solder and sealed. The end portions of the upper plate 73 and the lower plate 74 are bonded by brazing.

  FIG. 4 is a plan view showing the hot plate 71. As shown in FIG. 4, the hot plate 71 includes a disk-shaped zone 711 and an annular zone 712 that are concentrically arranged in a central portion of a region facing the semiconductor wafer W to be held, and the zone 712. There are four zones 713 to 716 obtained by equally dividing a peripheral substantially annular region into four equal parts in the circumferential direction, and a slight gap is formed between the zones. The hot plate 71 is provided with three through holes 77 through which the support pins 70 are inserted, every 120 ° on the circumference of the gap between the zone 711 and the zone 712.

  Cylindrical pin hole sleeves 78 are fitted into the three through holes 77. The pin hole sleeve 78 has a height in the range of +/− 0.2 mm and a thickness in the range of 0.5 to 10 mm with respect to the susceptor surface in accordance with the shape of the susceptor 72. The pin hole sleeve 78 is fitted into the through hole 77 with a margin of about 1 mm. In the case where the susceptor 72 is made of quartz, if any material of ALN, SiC, alumina, carbon, or silicon having a higher thermal conductivity than quartz is used as the material forming the pin hole sleeve, the through hole 77 is used. The temperature of the part corresponding to can be set higher than in the case of quartz.

  FIG. 5 is a graph showing a temperature difference between the through hole and a target temperature in the vicinity thereof. Fig.5 (a) is a graph which shows the deviation with respect to the target temperature in a prior art, and FIG.5 (b) is a graph which shows the deviation with respect to the target temperature in this invention. As is clear from FIGS. 5A and 5B, the present invention in which the cylindrical pin hole sleeve 78 is fitted in the three through holes 77 has a smaller deviation from the target temperature than the prior art. . Therefore, the present invention can suppress the temperature drop of the through-hole 77 portion for the support pins 70 as compared with the prior art, and uniformize the heat treatment of the semiconductor wafer W.

  In each of the six zones 711 to 716, heaters are individually formed so that mutually independent resistance heating wires 76 circulate, and each zone is individually formed by a heater built in each zone. Heated. The semiconductor wafer W held on the substrate holder 7 is heated by heaters built in the six zones 711 to 716. Each of the zones 711 to 716 is provided with a sensor 710 that measures the temperature of each zone using a thermocouple. Each sensor 710 passes through the inside of a substantially cylindrical shaft 41 and is connected to the control unit 3.

  When the hot plate 71 is heated, the resistance heating wire disposed in each zone is set so that the temperature of each of the six zones 711 to 716 measured by the sensor 710 becomes a predetermined temperature. The amount of power supplied to 76 is controlled by the control unit 3. The temperature control of each zone by the control unit 3 is performed by PID (Proportional, Integral, Derivative) control. In the hot plate 71, the temperature of each of the zones 711 to 716 is continuously measured until the heat treatment of the semiconductor wafer W (when the plurality of semiconductor wafers W are continuously processed, the heat treatment of all the semiconductor wafers W) is completed. Then, the power supply amount to the resistance heating wire 76 disposed in each zone is individually controlled, that is, the temperature of the heater built in each zone is individually controlled, and the temperature of each zone becomes the set temperature. Maintained. The set temperature of each zone can be changed by an offset value set individually from the reference temperature.

  The resistance heating wires 76 respectively disposed in the six zones 711 to 716 are connected to a power supply source (not shown) via a power line passing through the inside of the shaft 41. On the way from the power supply source to each zone, the power lines from the power supply source are arranged so as to be electrically insulated from each other inside a stainless tube filled with an insulator such as magnesia (magnesium oxide). The The interior of the shaft 41 is open to the atmosphere.

  Next, referring again to FIG. 1, the lamp house 5 is provided above the substrate holding portion 7 in the chamber 6. The lamp house 5 includes a flash light source including a plurality of (30 in this embodiment) xenon flash lamps FL and a reflector 52 provided so as to cover the light source inside the housing 51. Configured. A lamp light emission window 53 is attached to the bottom of the casing 51 of the lamp house 5. The lamp light radiation window 53 constituting the floor of the lamp house 5 is a plate-like member made of quartz. By installing the lamp house 5 above the chamber 6, the lamp light emission window 53 faces the chamber window 61. The lamp house 5 heats the semiconductor wafer W by irradiating the semiconductor wafer W held by the substrate holder 7 in the chamber 6 with flash light from the flash lamp FL via the lamp light emission window 53 and the chamber window 61. To do.

  Each of the plurality of flash lamps FL is a rod-shaped lamp having a long cylindrical shape, and the longitudinal direction of each of the flash lamps FL is along the main surface of the semiconductor wafer W held by the substrate holder 7 (that is, along the horizontal direction). ) They are arranged in a plane so as to be parallel to each other. Therefore, the plane formed by the arrangement of the flash lamps FL is also a horizontal plane.

  The xenon flash lamp FL has a rod-shaped glass tube (discharge tube) in which xenon gas is sealed and an anode and a cathode connected to a capacitor at both ends thereof, and an outer peripheral surface of the glass tube. And a triggered electrode. Since xenon gas is an electrical insulator, electricity does not flow into the glass tube under normal conditions even if electric charges are accumulated in the capacitor. However, when the insulation is broken by applying a high voltage to the trigger electrode, the electricity stored in the capacitor instantaneously flows into the glass tube due to the discharge between the electrodes at both ends, and the excitation of the xenon atoms or molecules at that time Light is emitted. In such a xenon flash lamp FL, the electrostatic energy stored in the capacitor in advance is converted into an extremely short light pulse of 0.1 millisecond to 10 millisecond, which is extremely incomparable with a continuous light source. It has the feature that it can irradiate strong light.

  In addition, the reflector 52 is provided above the plurality of flash lamps FL so as to cover all of them. The basic function of the reflector 52 is to reflect the flash light emitted from the plurality of flash lamps FL toward the substrate holding unit 7. The reflector 52 is formed of an aluminum alloy plate, and the surface (the surface facing the flash lamp FL) is roughened by blasting to exhibit a satin pattern. The roughening process is performed if the surface of the reflector 52 is a perfect mirror surface, a regular pattern is generated in the intensity of the reflected light from the plurality of flash lamps FL, and the surface temperature distribution of the semiconductor wafer W This is because the uniformity of the is reduced.

  Further, the control unit 3 controls the various operation mechanisms 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 stores a CPU that performs various arithmetic processes, a ROM that is a read-only memory that stores basic programs, a RAM that is a readable and writable memory that stores various information, control software, data, and the like. It has a magnetic disk.

  In addition to the above configuration, the heat treatment apparatus 1 is used for various cooling purposes in order to prevent excessive temperature rise of the chamber 6 and the lamp house 5 due to the heat energy generated from the flash lamp FL and the hot plate 71 during the heat treatment of the semiconductor wafer W. It has the structure of For example, water-cooled tubes (not shown) are provided on the chamber side 63 and the chamber bottom 62 of the chamber 6. The lamp house 5 has an air cooling structure provided with a gas supply pipe 55 and an exhaust pipe 56 for exhausting heat by forming a gas flow therein (see FIG. 1). Air is also supplied to the gap between the chamber window 61 and the lamp light emission window 53 to cool the lamp house 5 and the chamber window 61.

  Next, a processing procedure for the semiconductor wafer W in the heat treatment apparatus 1 will be described. Here, the semiconductor wafer W to be processed is a semiconductor substrate to which impurities (ions) are added by an ion implantation method, and activation of the added impurities is performed by light irradiation heating processing (annealing) by the heat treatment apparatus 1. . The processing procedure of the heat treatment apparatus 1 described below proceeds by the control unit 3 controlling each operation mechanism of the heat treatment apparatus 1.

  First, the substrate holder 7 is lowered from the processing position to the delivery position shown in FIG. The “processing position” is the position of the substrate holding part 7 when the semiconductor wafer W is irradiated with light from the flash lamp FL. The “delivery position” is the position of the substrate holding part 7 when the semiconductor wafer W is carried in and out of the chamber 6, and is the position in the chamber 6 of the substrate holding part 7 shown in FIG. The reference position of the substrate holding unit 7 in the heat treatment apparatus 1 is the processing position. Before the processing, the substrate holding unit 7 is located at the processing position, and this is lowered to the delivery position at the start of processing. As shown in FIG. 1, when the holding unit 7 is lowered to the delivery position, it approaches the chamber bottom 62, and the tip of the support pin 70 penetrates the holding unit 7 and protrudes above the substrate holding unit 7.

  Next, when the substrate holder 7 is lowered to the delivery position, the valve 82 and the valve 87 are opened, and normal temperature nitrogen gas is introduced into the heat treatment space 65 of the chamber 6. Subsequently, the gate valve 185 is opened to open the transfer opening 66, and the semiconductor wafer W is loaded into the chamber 6 through the transfer opening 66 by the transfer robot outside the apparatus and placed on the plurality of support pins 70. Is done.

  The purge amount of nitrogen gas into the chamber 6 when the semiconductor wafer W is loaded is about 40 liters / minute, and the supplied nitrogen gas is moved from the gas introduction buffer 83 in the direction of the arrow AR4 shown in FIG. Then, the exhaust gas is exhausted by utility exhaust via the discharge path 86 and the valve 87 shown in FIG. A part of the nitrogen gas supplied to the chamber 6 is also discharged from an outlet (not shown) provided inside the bellows 47. In each step described below, nitrogen gas is continuously supplied to and exhausted from the chamber 6, and the supply amount of the nitrogen gas is variously changed according to the processing process of the semiconductor wafer W.

  When the semiconductor wafer W is loaded into the chamber 6, the transfer opening 66 is closed by the gate valve 185. Then, the substrate holder 7 is raised from the delivery position to the processing position close to the chamber window 61 by the substrate holder lifting mechanism 4. In the process in which the substrate holding unit 7 is lifted from the delivery position, the semiconductor wafer W is transferred from the support pins 70 to the susceptor 72 of the substrate holding unit 7, and is placed and supported on the recess 176 of the susceptor 72 in a horizontal posture. In this state, the semiconductor wafer W is placed in the center of the concave portion 176 of the susceptor 72, but the semiconductor wafer W may be slightly slid and its end portion may be in contact with the tapered surface of the concave portion 176. When the substrate holder 7 is raised to the processing position, the semiconductor wafer W supported by the susceptor 72 is also held at the processing position.

  Each of the six zones 711 to 716 of the hot plate 71 is heated to a predetermined temperature by a heater (resistive heating wire 76) individually incorporated in each zone (between the upper plate 73 and the lower plate 74). ing. When the substrate holding part 7 rises to the processing position and the semiconductor wafer W comes into contact with the substrate holding part 7, the semiconductor wafer W is preheated by the heater built in the hot plate 71, and the temperature gradually rises.

  Preheating is performed at this processing position for about 60 seconds, and the temperature of the semiconductor wafer W rises to a preset preheating temperature T1. The preheating temperature T1 is set to about 200 ° C. to 800 ° C., preferably about 350 ° C. to 550 ° C., in which impurities added to the semiconductor wafer W are not likely to diffuse due to heat.

  After the preheating time of about 60 seconds elapses, flash light is emitted from the flash lamp FL of the lamp house 5 toward the semiconductor wafer W under the control of the control unit 3 while the substrate holding unit 7 is positioned at the processing position. At this time, a part of the flash light emitted from the flash lamp FL goes directly to the substrate holder 7 in the chamber 6, and the other part is once reflected by the reflector 52 and then goes into the chamber 6. The flash heating of the semiconductor wafer W is performed by the irradiation of the flash light. Since flash heating is performed by flash light irradiation from the flash lamp FL, the surface temperature of the semiconductor wafer W can be increased in a short time.

  That is, the flash light irradiated from the flash lamp FL of the lamp house 5 is converted to a light pulse whose electrostatic energy stored in advance is extremely short, and the irradiation time is about 0.1 to 10 milliseconds. A short and strong flash. Then, the surface temperature of the semiconductor wafer W flash-heated by flash light irradiation from the flash lamp FL instantaneously rises to a processing temperature T2 of about 1000 degrees Celsius to 1100 degrees Celsius, and impurities added to the semiconductor wafer W After being activated, the surface temperature drops rapidly. As described above, in the heat treatment apparatus 1, the surface temperature of the semiconductor wafer W can be raised and lowered in a very short time, so that the impurities are activated while suppressing diffusion of impurities added to the semiconductor wafer W due to heat. Can do. Since the time required for activation of the added impurity is extremely short compared to the time required for thermal diffusion, activation is possible even for a short time when no diffusion of about 0.1 millisecond to 10 millisecond occurs. Is completed.

  Further, by preheating the semiconductor wafer W by the substrate holding unit 7 before the flash heating, the surface temperature of the semiconductor wafer W can be rapidly raised to the processing temperature T2 by the flash light irradiation from the flash lamp FL. it can.

  After the flash heating is finished and the standby for about 10 seconds at the processing position, the substrate holder 7 is lowered again to the delivery position shown in FIG. 1 by the substrate holder lifting mechanism 4, and the semiconductor wafer W is supported from the substrate holder 7. Passed to pin 70. Subsequently, the transfer opening 66 closed by the gate valve 185 is opened, and the semiconductor wafer W placed on the support pins 70 is unloaded by a transfer robot outside the apparatus, and the semiconductor wafer W is flushed in the heat treatment apparatus 1. The heat treatment is completed.

  As described above, nitrogen gas is continuously supplied to the chamber 6 during the heat treatment of the semiconductor wafer W in the heat treatment apparatus 1, and the supply amount is about 30 liters / second when the substrate holding unit 7 is located at the processing position. When the substrate holding unit 7 is located at a position other than the processing position, the rate is about 40 liters / minute.

  By the way, the surface temperature of the semiconductor wafer W that is flash-heated by flash irradiation of about several milliseconds from the flash lamp FL instantaneously rises to the processing temperature T2 of about 1000 degrees Celsius to about 1100 degrees Celsius, while the back surface temperature at that moment. Does not increase so much from the preheating temperature T1 of about 350 to 550 degrees Celsius. For this reason, rapid thermal expansion occurs only on the wafer surface side, and the semiconductor wafer W warps so that the upper surface is convex. Then, at the next moment, while the surface temperature of the semiconductor wafer W rapidly decreases, the back surface temperature also slightly increases due to heat conduction from the front surface to the back surface, so that the semiconductor wafer W is warped in the opposite direction. Stress to act. As a result, the semiconductor wafer W vibrates vigorously on the susceptor 72, and the semiconductor wafer W may be cracked by the impact at that time.

  In this embodiment, the lamp house 5 is provided with 30 flash lamps FL. However, the present invention is not limited to this, and the number of flash lamps FL can be any number. The flash lamp FL is not limited to a xenon flash lamp, and may be a krypton flash lamp.

  Further, the substrate to be processed by the heat treatment apparatus according to the present invention is not limited to a semiconductor wafer, and may be a glass substrate used for a liquid crystal display device or the like.

DESCRIPTION OF SYMBOLS 1 Heat processing apparatus 3 Control part 4 Substrate holding part raising / lowering mechanism 5 Lamp house 6 Chamber 7 Substrate holding part 60 Upper opening 61 Chamber window 65 Heat treatment space 70 Support pin 71 Hot plate 72 Susceptor 73 Upper plate 74 Lower plate 75 Pin 76 Resistance heating wire 77 Through-hole 78 Pin hole sleeve FL Flash lamp W Semiconductor wafer

Claims (3)

In a heat treatment apparatus that heats a substrate by irradiating the substrate with light,
A substrate holding unit that has a hot plate for preheating the substrate and a susceptor mounted on the hot plate, and holds and holds the substrate in a horizontal position;
A light irradiation means for irradiating light to the substrate supported by the substrate support;
A support pin for raising and lowering the substrate relative to the substrate holding part while supporting the substrate;
The hot plate and the susceptor are provided with a through-hole penetrating for the support pin,
A heat treatment apparatus, wherein a pin hole sleeve made of a material having a higher thermal conductivity than the susceptor is formed in the through hole. The heat treatment apparatus according to claim 1,
A material for forming the pin hole sleeve is formed of any one of ALN, SiC, alumina, carbon, and silicon. In the heat treatment apparatus according to claim 1 or 2,
The heat treatment apparatus, wherein the pin hole sleeve is fitted in the through hole.

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