JP5813291B2 - Heat treatment apparatus and heat treatment method - Google Patents

Description

  The present invention relates to a heat treatment apparatus and a heat treatment for heating a thin plate-shaped precision electronic substrate (hereinafter simply referred to as “substrate”) such as a semiconductor wafer or a glass substrate for a liquid crystal display device by irradiating flash light. Regarding the method.

  In recent years, in an impurity (ion) activation process of a semiconductor wafer after ion implantation, it is required to suppress the diffusion of impurities and make the junction depth shallower as the pattern of a semiconductor device becomes finer. As a technology that satisfies these requirements, flash lamp annealing is used to irradiate the surface of a semiconductor wafer with flash light (flash) using a xenon flash lamp (hereinafter, simply referred to as “flash lamp” means xenon flash lamp). (FLA) is drawing attention.

  The radiation spectral distribution of a xenon flash lamp ranges from the ultraviolet region to the near infrared region, has a shorter wavelength than the 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. Further, it has been found that if the flash light irradiation is performed for a very short time of several milliseconds or less, only the vicinity of the surface of the semiconductor wafer can be selectively heated. Therefore, in flash lamp annealing, the surface of a semiconductor wafer into which ions are implanted is irradiated with flash light, and only the surface of the semiconductor wafer is heated to 1000 ° C. or higher in a very short time (several milliseconds or less). it can. As a result, only impurity activation can be performed without deeply diffusing the impurities.

  In addition, the current flowing through the flash lamp is chopper-controlled using an insulated gate bipolar transistor (IGBT), and the flash lamp is turned on for a longer time (approximately 10 milliseconds or more) than simply causing the flash lamp to emit light. Techniques for causing light emission are proposed in Patent Documents 1 and 2. By using such a technique, the surface temperature of the semiconductor wafer can be raised and lowered somewhat gently, and better impurity activation and recovery of defects introduced in a layer deeper than the impurity implantation layer can be realized. be able to. Even if it is a gradual temperature increase / decrease, it is just a comparison with the ultra-high speed temperature increase / decrease that simply causes the flash lamp to emit light. It is warm.

JP 2009-070948 A JP 2009-099758 A

  In the techniques disclosed in Patent Documents 1 and 2, a pulse signal to be applied to the gate of an insulated gate bipolar transistor is set, and the current flowing through the flash lamp is turned on and off according to the pulse signal. At the stage of setting the pulse signal, the current value actually flowing through the flash lamp, the light emission intensity of the flash lamp, and the surface temperature of the semiconductor wafer can only be predicted, and the processing result is evaluated by some method (for example, sheet resistance value measurement). For the first time, the surface temperature and the like are detected afterwards. For this reason, in order to obtain the optimum light emission intensity and surface temperature, it is necessary to repeatedly set the pulse signal by a trial and error method. As a result, there is a problem that the setting work of the pulse signal becomes complicated and requires a long time.

  The present invention has been made in view of the above problems, and an object thereof is to provide a heat treatment apparatus and a heat treatment method capable of easily optimizing control variables related to light emission of a flash lamp.

In order to solve the above-mentioned problems, a first aspect of the present invention provides a heat treatment apparatus for heating a substrate by irradiating the substrate with flash light, a holding means for holding the substrate, and a substrate held by the holding means. A flash lamp for irradiating a flash light, an insulated gate bipolar transistor connected in series with the flash lamp, a capacitor and a coil, a measuring means for measuring a control variable related to light emission of the flash lamp, and the measuring means An IGBT that switches the insulated gate bipolar transistor to an on state or an off state by applying a signal to the gate of the insulated gate bipolar transistor so that the control variable becomes a preset target value based on the obtained measurement value and a control unit, wherein the control variable is the flash A current flowing through the pump, said measuring means is characterized by a current monitor for measuring the current flowing through the circuit including the flash lamp.

  According to a second aspect of the present invention, the heat treatment apparatus according to the first aspect of the present invention further comprises setting means for setting a time profile of the target value of the control variable.

  Further, the invention of claim 3 is the heat treatment apparatus according to claim 1 or 2, wherein the IGBT control means is configured such that the measured value of the control variable is larger than a target value and exceeds an upper limit allowable range. The insulated gate bipolar transistor is turned off, and the insulated gate bipolar transistor is turned on when it is smaller than the lower limit allowable range than the target value.

According to a fourth aspect of the present invention, in a heat treatment method for heating a substrate by irradiating the substrate with flash light, the capacitor is stored in a flash lamp connected in series with a capacitor, a coil and an insulated gate bipolar transistor. A light emission step of irradiating the substrate with flash light by flowing the generated charge, a measurement step of measuring a control variable related to light emission of the flash lamp, and a measurement value obtained in the measurement step And an IGBT control step of applying a signal to the gate of the insulated gate bipolar transistor to switch the insulated gate bipolar transistor to an on state or an off state so that the control variable becomes a preset target value , The control variable is a current value flowing through the flash lamp. It is characterized in.

The invention according to claim 5 is the heat treatment method according to claim 4 , further comprising a setting step of setting a time profile of the target value of the control variable.

The invention according to claim 6 is the heat treatment method according to claim 4 or 5 , wherein, in the IGBT control step, the measured value of the control variable is larger than a target value and exceeds the upper limit allowable range. The insulated gate bipolar transistor is turned off, and the insulated gate bipolar transistor is turned on when it is smaller than the lower limit allowable range than the target value.

According to the first to third aspects of the invention, based on the measured value obtained by the measuring means, the control variable of the insulated gate bipolar transistor is set so that the control variable related to the light emission of the flash lamp becomes a preset target value. Since the signal is applied to the gate to switch the insulated gate bipolar transistor to the on state or the off state, the insulated gate bipolar transistor is controlled on and off so that the measured value matches the target value, which is related to the light emission of the flash lamp. Control variables can be easily optimized.

  In particular, according to the invention of claim 2, since the setting means for setting the time profile of the target value of the control variable is provided, the control variable related to the flash lamp emission can be easily optimized according to the time profile of the target value. Can do.

According to the inventions of claims 4 to 6 , the insulated gate is configured so that the control variable related to the light emission of the flash lamp becomes a preset target value based on the measured value obtained in the measuring step. Since a signal is applied to the gate of the bipolar transistor to switch the insulated gate bipolar transistor to the on state or the off state, the insulated gate bipolar transistor is controlled to be turned on and off so that the measured value matches the target value. The control variables related to can be easily optimized.

In particular, according to the invention of claim 5 , since the setting step for setting the time profile of the target value of the control variable is provided, the control variable related to the light emission of the flash lamp can be easily optimized according to the time profile of the target value. Can do.

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 shows the gas path of the heat processing apparatus of FIG. It is sectional drawing which shows the structure of a holding | maintenance part. It is a top view which shows a hot plate. It is a longitudinal cross-sectional view which shows the structure of the heat processing apparatus of FIG. It is a figure which shows the drive circuit of a flash lamp. It is a figure which shows the change of the surface temperature of the semiconductor wafer after preheating is started. It is a flowchart which shows the procedure of on-off control of IGBT. It is a figure which shows an example of the time profile of the target value of a control variable. It is a figure which shows the measured value of a control variable when IGBT is on-off controlled according to the target value of FIG. It is a longitudinal cross-sectional view which shows the structure of the heat processing apparatus of 2nd Embodiment. It is a figure which shows the drive circuit of the flash lamp of 2nd Embodiment. It is a longitudinal cross-sectional view which shows the structure of the heat processing apparatus of 3rd Embodiment. It is a figure which shows the drive circuit of the flash lamp of 3rd Embodiment.

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

<First Embodiment>
First, 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 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 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 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 (in this embodiment) for supporting the semiconductor wafer W from the lower surface (surface opposite to the side irradiated with light from the lamp house 5) through the holding portion 7. 3) support pins 70 are provided upright. 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 63 has a transfer opening 66 for carrying in and out 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, argon (Ar) gas, etc. Alternatively, an introduction path 81 for introducing oxygen (O 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) through 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 holding unit 7 that holds the semiconductor wafer W in a horizontal position in the chamber 6 and performs preheating of the semiconductor wafer W held before light irradiation, and a holding unit. And a holding unit elevating mechanism 4 that elevates 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 arranged around the shaft 41 in the present embodiment), a fixed plate 44, a ball screw 45, It has a nut 46 and a motor 40. A substantially circular lower opening 64 having a smaller diameter than the 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 hold the holding portion. 7 (strictly speaking, the hot plate 71 of the holding unit 7) is connected to the lower surface of the holding unit 7 to support it.

  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 holding unit 7 via 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 holding part 7 is raised and lowered by the holding part raising / lowering mechanism 4, the motor 40 as the 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 follows the guide member 43. Move vertically. As a result, the shaft 41 fixed to the moving plate 42 moves along the vertical direction, and the holding unit 7 connected to the shaft 41 moves between the delivery position of the semiconductor wafer W shown in FIG. 1 and the semiconductor wafer W shown in FIG. Move up and down smoothly between the processing positions.

  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 holding part 7 does not rise above a predetermined position below the chamber window 61, and the collision between the holding part 7 and the chamber window 61 is prevented.

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

  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 flange-shaped member 411. The bellows 47 is contracted when the holding portion 7 is raised with respect to the chamber bottom 62 by the holding portion lifting mechanism 4, and the bellows 47 is expanded when the holding portion 7 is lowered. When the holding unit 7 moves up and down, the airtight state in the heat treatment space 65 is maintained by the expansion and contraction of the bellows 47.

  FIG. 3 is a cross-sectional view showing the configuration of the holding unit 7. The holding unit 7 is installed on a hot plate (heating plate) 71 that preheats the semiconductor wafer W (so-called assist heating), and an upper surface of the hot plate 71 (a surface on the side where the holding unit 7 holds the semiconductor wafer W). The susceptor 72 is provided. As described above, the shaft 41 that moves up and down the holding unit 7 is connected to the lower surface of the holding unit 7. The susceptor 72 is made of quartz (or may be aluminum nitride (AIN) or the like), and a pin 75 for preventing displacement of the semiconductor wafer W is provided on the upper surface thereof. The susceptor 72 is installed on the hot plate 71 with its lower surface in surface contact with the upper surface of the hot plate 71. Thus, the susceptor 72 diffuses the thermal energy from the hot plate 71 and transmits it to the semiconductor wafer W placed on the upper surface of the susceptor 72, and can be removed from the hot plate 71 and cleaned during maintenance.

  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 disc-shaped zone 711 and an annular zone 712 that are concentrically arranged in a central portion of a region facing the held semiconductor wafer W, and a 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.

  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 by the holding unit 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 plural 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, the lamp house 5 includes a light source composed of a plurality of (30 in this embodiment) xenon flash lamps FL inside the housing 51, and a reflector 52 provided so as to cover the light source, It is configured with. 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 holding unit 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. .

  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 holding unit 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.

  FIG. 6 is a diagram showing a driving circuit for the flash lamp FL. As shown in the figure, a capacitor 93, a coil 94, a flash lamp FL, and an IGBT (insulated gate bipolar transistor) 96 are connected in series. The flash lamp FL includes a rod-shaped glass tube (discharge tube) 92 in which xenon gas is sealed and an anode and a cathode are disposed at both ends thereof, and a trigger electrode provided on the outer peripheral surface of the glass tube 92. 91. A predetermined voltage is applied to the capacitor 93 by the power supply unit 95, and a charge corresponding to the applied voltage is charged. A voltage can be applied from the trigger circuit 97 to the trigger electrode 91. The timing at which the trigger circuit 97 applies a voltage to the trigger electrode 91 is controlled by the control unit 3.

  The IGBT 96 is a bipolar transistor in which a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is incorporated in a gate portion, and is a switching element suitable for handling high power. The IGBT controller 21 is connected to the gate of the IGBT 96. The IGBT control unit 21 is a circuit that drives the IGBT 96 by applying a signal to the gate of the IGBT 96. Specifically, the IGBT 96 is turned on when the IGBT controller 21 applies a voltage higher than a predetermined value (Hi voltage) to the gate of the IGBT 96, and the IGBT 96 is turned off when a voltage lower than the predetermined value (Low voltage) is applied. It becomes. In this way, the circuit including the flash lamp FL is turned on / off by the IGBT 96.

  Even if the IGBT 96 is turned on while the capacitor 93 is charged and a high voltage is applied to both end electrodes of the glass tube 92, the xenon gas is electrically an insulator, so that the glass is normal in the state. No electricity flows in the tube 92. However, when the trigger circuit 97 applies a voltage to the trigger electrode 91 to break the insulation, an electric current instantaneously flows in the glass tube 92 due to the discharge between the two end electrodes, and the excitation of the xenon atoms or molecules at that time Light is emitted.

  In the first embodiment, the current monitor 25 is provided in a circuit including the flash lamp FL. As the current monitor 25, a clamp meter (overhead ammeter) that measures a current value flowing through the flash lamp FL by measuring a magnetic field generated when a current flows through a circuit including the flash lamp FL can be used. The current value measured by the current monitor 25 is transmitted to the IGBT control unit 21.

  The reflector 52 in FIG. 1 is provided above the plurality of flash lamps FL so as to cover the entirety thereof. The basic function of the reflector 52 is to reflect the light emitted from the plurality of flash lamps FL toward the 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 when the surface of the reflector 52 is a perfect mirror surface, and a regular pattern is generated in the intensity of the reflected light from the plurality of flash lamps FL, so that the surface temperature distribution of the semiconductor wafer W is obtained. This is because the uniformity of the is reduced.

  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 is configured with a magnetic disk. The control unit 3 includes a target value setting unit 32 and is connected to the input unit 33. As the input unit 33, various known input devices such as a keyboard, a mouse, and a touch panel can be employed. Based on the input content from the input unit 33, the target value setting unit 32 sets a target value waveform (time profile) of a control variable (current value flowing through the flash lamp FL in the first embodiment), and the waveform is IGBT controlled. Input to the unit 21.

  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 FIGS. 1 and 5). 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. The semiconductor wafer W to be processed here is a semiconductor substrate to which impurities (ions) are added by an ion implantation method. The activation of the impurities is performed by flash light irradiation heat treatment (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 holding unit 7 is lowered from the processing position shown in FIG. 5 to the delivery position shown in FIG. The “processing position” is the position of the holding unit 7 when the semiconductor wafer W is irradiated with light from the flash lamp FL, and is the position in the chamber 6 of the holding unit 7 shown in FIG. Further, the “delivery position” is the position of the holding unit 7 when the semiconductor wafer W is carried in and out of the chamber 6, and is the position of the holding unit 7 shown in FIG. The reference position of the holding unit 7 in the heat treatment apparatus 1 is the processing position. Before the processing, the 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 portion 7 is lowered to the delivery position, the holding portion 7 comes close to the chamber bottom portion 62, and the tip of the support pin 70 penetrates the holding portion 7 and protrudes above the holding portion 7.

  Next, when the holding unit 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. The holding unit lifting mechanism 4 raises the holding unit 7 from the delivery position to a processing position close to the chamber window 61. In the process in which the 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 holding unit 7 and is placed and held on the upper surface of the susceptor 72. When the holding unit 7 is raised to the processing position, the semiconductor wafer W held 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 holding unit 7 rises to the processing position and the semiconductor wafer W comes into contact with the holding unit 7, the semiconductor wafer W is preheated by the heater built in the hot plate 71 and the temperature gradually rises.

  FIG. 7 is a diagram showing a change in the surface temperature of the semiconductor wafer W since the preheating is started. Preheating is performed for a time tp at the processing position, 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 700 ° C., preferably about 350 ° C. to 600 ° C. (500 ° C. in the present embodiment) at which impurities added to the semiconductor wafer W do not diffuse due to heat. . The time tp for preheating the semiconductor wafer W is about 3 seconds to 200 seconds (60 seconds in the present embodiment). The distance between the holding unit 7 and the chamber window 61 can be arbitrarily adjusted by controlling the rotation amount of the motor 40 of the holding unit lifting mechanism 4.

  After the preheating time of time tp has elapsed, light irradiation heating of the semiconductor wafer W by the flash lamp FL is started at time A. When irradiating light from the flash lamp FL, charges are accumulated in the capacitor 93 by the power supply unit 95 in advance. Then, in a state where charges are accumulated in the capacitor 93, the IGBT control unit 21 controls on / off of the IGBT 96 to cause the flash lamp FL to emit light.

FIG. 8 is a flowchart showing the procedure of on / off control of the IGBT 96. Prior to the light irradiation heating by the flash lamp FL, the target value of the control variable is set in advance (step S11). In the first embodiment, a control variable related to light emission of the flash lamp FL is a current value flowing through the flash lamp FL, and a target value of the current value is input from the input unit 33. Specifically, for example, a combination of the time t _n from the control start by the IGBT control unit 21 and the target value of the current value A _n at that time _{t n (t 1, A 1} ), (t 2, A 2) , (T ₃ , A ₃ )... (T _n , A _n )... May be sequentially input from the input unit 33.

  When the operator inputs such a target value of the current value to the control unit 3 from the input unit 33, the target value setting unit 32 of the control unit 3 based on that inputs a time profile of the target value of the current value as shown in FIG. Set. The time profile of the target value of the current value as shown in FIG. 9 set by the target value setting unit 32 is transmitted to the IGBT control unit 21 and stored in the storage unit of the IGBT control unit 21 (not shown).

  In this way, the target value of the current value is set in advance, and the on / off control of the IGBT 96 after step S12 is started. When the on / off control of the IGBT 96 is started, first, the IGBT control unit 21 applies a voltage of a predetermined value or more to the gate of the IGBT 96 to turn on the IGBT 96 (step S12). In addition, the control unit 3 controls the trigger circuit 97 to apply a trigger voltage to the trigger electrode 91 in synchronization with the timing when the IGBT control unit 21 first turns on the IGBT 96. When the charge is accumulated in the capacitor 93 and the IGBT 96 is turned on, and when a high voltage is applied to the trigger electrode 91 in synchronization therewith, the charge accumulated in the capacitor 93 is transferred to the glass tube 92 of the flash lamp FL. A current starts to flow between the electrodes at both ends, and light is emitted by excitation of atoms or molecules of xenon at that time. That is, the flash lamp FL starts to emit light, and the current value flowing through the flash lamp FL increases with time.

  After the IGBT control unit 21 turns on the IGBT 96 as an initial state, the processing of Step S13 to Step S18 is repeated and the IGBT 96 is on / off controlled. FIG. 10 is a diagram showing measured values of control variables when the IGBT 96 is on / off controlled according to the target value of FIG. In FIG. 10, the time profile (FIG. 9) of the target value of the current value set by the target value setting unit 32 is indicated by a dotted line, and the measured value of the current value is indicated by a solid line. Also, in FIG. 10, what is indicated by a one-dot chain line is an upper limit allowable value and a lower limit allowable value. The upper limit allowable value and the lower limit allowable value are also input in advance from the input unit 33 (for example, the upper limit allowable range is + 10% of the target value, the lower limit allowable range is + 10% of the target value, etc.).

  First, control variable measurement is performed (step S13). In the first embodiment, the current monitor 25 measures the value of the current flowing through the circuit including the flash lamp FL. Then, the current value measured by the current monitor 25 is transmitted to the IGBT control unit 21.

  Then, it progresses to step S14 and it is determined by the IGBT control part 21 whether the obtained measured value is larger than the target value at the time (at the time of measurement) exceeding an upper limit allowable range. When the measured value is larger than the upper limit allowable range than the target value, the process proceeds to step S15, and the IGBT control unit 21 turns off the IGBT 96. When the IGBT 96 is turned off, the circuit including the flash lamp FL is opened, and the current value flowing through the flash lamp FL decreases with time. On the other hand, if the measured value is not larger than the upper limit allowable range than the target value, the process proceeds to step S16.

  In step S16, the IGBT controller 21 determines whether or not the obtained measured value is smaller than the target value at that time (measurement time) exceeding the lower limit allowable range. If the measured value is smaller than the lower limit allowable range than the target value, the process proceeds to step S17, and the IGBT control unit 21 turns the IGBT 96 on. When the IGBT 96 is turned on, the circuit including the flash lamp FL is closed, and the value of the current flowing through the flash lamp FL increases with time. On the other hand, if the measured value is not smaller than the lower limit allowable range than the target value, the process proceeds to step S18.

  In step S18, it is determined whether the on / off control of the IGBT 96 has been completed. If not, the process returns to step S13. Specifically, the IGBT control unit 21 determines whether or not a predetermined on / off control time of the IGBT 96 determined from the time profile of the target value of the current value set by the target value setting unit 32 has elapsed. It ’s fine. The process of step S13 to step S18 is repeated until the ON / OFF control time of the IGBT 96 defined in advance elapses.

  The current monitor 25 can measure the value of the current flowing through the circuit including the flash lamp FL on the order of microseconds (10 microseconds or less). For this reason, the time required to execute one round of processing in steps S13 to S18 can be set to 50 microseconds to 100 microseconds. Even when the flash lamp FL is simply emitted (same as when the IGBT 96 is always turned on), the emission time is extremely short, from several milliseconds to several tens of milliseconds, but at least 100 microseconds. If the IGBT 96 can be controlled on and off at intervals of (0.1 milliseconds), the light emission of the flash lamp FL can be sufficiently controlled.

  In this way, as a result of the processes of Step S13 to Step S18 being repeatedly executed, the actual value of the current value flowing through the flash lamp FL (that is, the current value actually flowing through the flash lamp FL) is indicated by the solid line in FIG. It changes as shown. That is, as a result of the IGBT 96 being intermittently turned on / off, the light emission of the flash lamp FL is chopper-controlled, and the charge accumulated in the capacitor 93 is divided and consumed, and the flash lamp FL is turned off in a very short time. Repeats flashing. As shown in FIG. 10, the IGBT 96 is turned on before the current value flowing through the flash lamp FL becomes completely “0”, and the current value increases again. Therefore, the flash lamp FL repeatedly blinks. In the meantime, the light emission output is not completely “0”. Also, once the energization of the flash lamp FL is started and the IGBT 96 is turned on in a state where the current value remains at a predetermined value or more, the flash lamp can be turned on without applying a high voltage to the trigger electrode 91 thereafter. Current continues to flow through FL. That is, if a high voltage is applied to the trigger electrode 91 only when it is first turned on in step S12, then the current continues to flow through the flash lamp FL without applying the trigger voltage.

  It can be said that the on / off control procedure of the IGBT 96 shown in FIG. 8 is a feedback control of the IGBT 96. That is, based on the measured value of the current value flowing through the flash lamp FL obtained by the current monitor 25, the IGBT control unit 21 applies a signal to the gate of the IGBT 96 so that the current value becomes a preset target value. The IGBT 96 is switched to the on state or the off state. More specifically, the IGBT control unit 21 turns off the IGBT 96 when the measured current value is larger than the upper limit allowable range than the target value, and turns off the IGBT 96 when the measured current value is smaller than the lower limit allowable range. Turn on. As a result, the current value flowing through the flash lamp FL can be easily controlled to a preset target value.

  A current as shown by a solid line in FIG. 10 flows, and the flash lamp FL emits light, whereby the semiconductor wafer W held by the holding portion 7 at the processing position is irradiated with flash light. As a result, the surface temperature of the semiconductor wafer W is raised to the processing temperature T2 in a short time (see FIG. 7). The processing temperature T2 is a temperature at which the impurities injected into the semiconductor wafer W are activated, and is set to 1000 ° C. or higher.

  As described above, the light irradiation heating by the flash lamp FL is completed, and after waiting for about 10 seconds at the processing position, the holding unit 7 is lowered again to the delivery position shown in FIG. W is passed from the holding portion 7 to the support 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 the transfer robot outside the apparatus, and the light of the semiconductor wafer W in the heat treatment apparatus 1 is transferred. Irradiation 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 / minute when the holding unit 7 is located at the processing position. When the holding unit 7 is located at a position other than the processing position, the rate is about 40 liters / minute.

  In the first embodiment, a target value of the current value flowing through the flash lamp FL is set in advance as a control variable, and the current value is set in advance based on the measured value of the current value measured by the current monitor 25. The IGBT control unit 21 applies a signal to the gate of the IGBT 96 so as to obtain a value, thereby switching the IGBT 96 to an on state or an off state. In other words, the current value flowing through the flash lamp FL is measured by the current monitor 25 with a very short sampling time, the measured value is compared with the target value, and the feedback control (closed circuit control) is performed to control the IGBT 96 so that they match. )It is carried out.

  For this reason, it is not necessary to repeatedly set the pulse signal applied to the gate of the IGBT 96 by the trial and error method in order to optimize the current value flowing through the flash lamp FL, and the current value can be simplified simply by setting the target value. Can be optimized. As a result, the time required for optimizing the control variable (current value in the first embodiment) related to the light emission of the flash lamp can be greatly shortened. In addition, since the value of the current flowing through the flash lamp FL is stabilized, the reproducibility of the light irradiation heat treatment by the flash lamp FL can be improved.

Second Embodiment
Next, a second embodiment of the present invention will be described. FIG. 11 is a longitudinal sectional view showing the configuration of the heat treatment apparatus of the second embodiment. FIG. 12 is a diagram showing a driving circuit for the flash lamp FL of the second embodiment. In the second embodiment, the optical sensor 26 is installed in the heat treatment space 65 in the chamber 6. The light sensor 26 is a light detector that measures the light emission intensity when the flash lamp FL emits light, and it is preferable to use a photodiode having a high response speed. A current (photocurrent) generated by irradiating the optical sensor 26 with flash light from the flash lamp FL is detected by a light amount monitor 27. The light amount monitor 27 converts the current value generated in the optical sensor 26 into the light emission intensity of the flash lamp FL, and transmits the value to the IGBT control unit 21. About the remaining structure, the heat processing apparatus of 2nd Embodiment is the same as that of 1st Embodiment.

  The processing procedure of the semiconductor wafer W in the second embodiment is also substantially the same as that in the first embodiment (see FIG. 8). However, in the second embodiment, the control variable related to the light emission of the flash lamp FL is the light emission intensity of the flash lamp FL. For this reason, in step S11, the operator inputs a target value of the light emission intensity of the flash lamp FL. Then, based on the input, the target value setting unit 32 of the control unit 3 sets a time profile of the target value of the light emission intensity and transmits it to the IGBT control unit 21.

  A target value of the light emission intensity of the flash lamp FL is set in advance, and the on / off control of the IGBT 96 after step S12 is executed. In the second embodiment, the light intensity of the flash lamp FL is measured by the optical sensor 26 and the light amount monitor 27 (step S13). The measured emission intensity is transmitted from the light amount monitor 27 to the IGBT control unit 21. Then, it is determined by the IGBT control unit 21 whether or not the obtained measured value is larger than the upper limit allowable range than the target value at that time (measurement time), and the measured value exceeds the upper limit allowable range than the target value. If it exceeds the maximum value, the IGBT control unit 21 turns off the IGBT 96 (steps S14 and S15).

  Next, it is determined by the IGBT control unit 21 whether or not the obtained measured value is smaller than the lower limit allowable range than the target value at that time, and the measured value is smaller than the lower limit allowable range than the target value. Sometimes, the IGBT control unit 21 turns on the IGBT 96 (steps S16 and S17). Note that the optical sensor 26 and the light amount monitor 27 can measure the light emission intensity of the flash lamp FL on the order of microseconds. For this reason, as in the first embodiment, the IGBT controller 21 can control the IGBT 96 on and off at intervals of at least 100 microseconds.

  In this way, also in the second embodiment, the IGBT 96 is feedback-controlled. That is, based on the measured value of the light emission intensity of the flash lamp FL obtained by the optical sensor 26 and the light quantity monitor 27, the IGBT control unit 21 sends a signal to the gate of the IGBT 96 so that the light emission intensity becomes a preset target value. Is applied to switch the IGBT 96 to an on state or an off state. More specifically, the IGBT control unit 21 turns off the IGBT 96 when the measured value of the light emission intensity exceeds the upper limit allowable range beyond the target value, and turns off the IGBT 96 when the measured value of the emission intensity is lower than the lower limit allowable range. Turn on. As a result, the light emission intensity of the flash lamp FL can be easily controlled to a preset target value.

  As described above, in the second embodiment, the target value of the light emission intensity of the flash lamp FL is set in advance as a control variable, and based on the measurement value of the light emission intensity measured by the light sensor 26 and the light amount monitor 27, The IGBT control unit 21 applies a signal to the gate of the IGBT 96 so that the emission intensity becomes a preset target value, thereby switching the IGBT 96 to the on state or the off state. In other words, the current value flowing through the flash lamp FL is measured by the optical sensor 26 and the light amount monitor 27 with a very short sampling time, and the measured value is compared with the target value to control the IGBT 96 so that they match. It is carried out.

  For this reason, as in the first embodiment, the light emission intensity of the flash lamp FL can be easily optimized simply by setting the target value. As a result, the time required for optimizing the control variable related to the light emission of the flash lamp (light emission intensity in the second embodiment) can be greatly reduced. In addition, since the light emission intensity of the flash lamp FL is stabilized, the reproducibility of the light irradiation heat treatment by the flash lamp FL can be improved.

<Third Embodiment>
Next, a third embodiment of the present invention will be described. FIG. 13 is a longitudinal sectional view showing the configuration of the heat treatment apparatus of the third embodiment. FIG. 14 is a diagram showing a driving circuit for the flash lamp FL of the third embodiment. In the third embodiment, the temperature sensor 28 is installed in the heat treatment space 65 in the chamber 6. The temperature sensor 28 is a radiation thermometer that measures the surface temperature of the semiconductor wafer W that has been irradiated with flash light. As the temperature sensor 28, an infrared sensor that receives infrared rays emitted from the surface of the semiconductor wafer W and measures the surface temperature is used, and a quantum infrared sensor (for example, a photodiode) having a high response speed is preferably used. . A current generated in the temperature sensor 28 by receiving infrared rays from the surface of the semiconductor wafer W is detected by a temperature monitor 29. The temperature monitor 29 converts the current value generated in the temperature sensor 28 into the surface temperature of the semiconductor wafer W and transmits the value to the IGBT control unit 21. About the remaining structure, the heat processing apparatus of 3rd Embodiment is the same as that of 1st Embodiment. The temperature monitor 29 may incorporate a function for correcting the emissivity of the semiconductor wafer W.

  The processing procedure of the semiconductor wafer W in the third embodiment is substantially the same as that in the first embodiment (see FIG. 8). However, in the third embodiment, the control variable related to the light emission of the flash lamp FL is the surface temperature of the semiconductor wafer W held in the holding unit 7. For this reason, in step S11, the operator inputs a target value of the surface temperature of the semiconductor wafer W. Based on the input, the target value setting unit 32 of the control unit 3 sets a time profile of the target value of the surface temperature and transmits it to the IGBT control unit 21.

  A target value of the surface temperature of the semiconductor wafer W is set in advance, and the on / off control of the IGBT 96 after step S12 is executed. In the third embodiment, the surface temperature of the semiconductor wafer W held on the processing position holder 7 is measured by the temperature sensor 28 and the temperature monitor 29 (step S13). The measured surface temperature of the semiconductor wafer W is transmitted from the temperature monitor 29 to the IGBT controller 21. Then, it is determined by the IGBT control unit 21 whether or not the obtained measured value is larger than the upper limit allowable range than the target value at that time (measurement time), and the measured value exceeds the upper limit allowable range than the target value. If it exceeds the maximum value, the IGBT control unit 21 turns off the IGBT 96 (steps S14 and S15).

  Next, it is determined by the IGBT control unit 21 whether or not the obtained measured value is smaller than the lower limit allowable range than the target value at that time, and the measured value is smaller than the lower limit allowable range than the target value. Sometimes, the IGBT control unit 21 turns on the IGBT 96 (steps S16 and S17). Although the response speed itself of the temperature sensor 28 is on the order of microseconds, the output varies greatly compared to the current monitor 25 of the first embodiment and the optical sensor 26 of the second embodiment, and the sampling results are obtained several times. After smoothing by the temperature monitor 29, it is necessary to transmit to the IGBT control unit 21. Even in such a case, the measured value of the surface temperature can be transmitted from the temperature monitor 29 to the IGBT controller 21 at intervals of about 100 microseconds. That is, the measurement of the control variable in step S12 can be executed with a cycle time of about 100 microseconds. For this reason, also in the third embodiment, the IGBT control unit 21 can perform on / off control of the IGBT 96 at intervals of at least 100 microseconds.

  Thus, also in the third embodiment, the IGBT 96 is feedback-controlled. That is, based on the measured value of the surface temperature of the semiconductor wafer W obtained by the temperature sensor 28 and the temperature monitor 29, the IGBT control unit 21 sends a signal to the gate of the IGBT 96 so that the surface temperature becomes a preset target value. Is applied to switch the IGBT 96 to an on state or an off state. More specifically, the IGBT control unit 21 turns off the IGBT 96 when the measured value of the surface temperature is larger than the upper limit allowable range than the target value, and turns off the IGBT 96 when it is smaller than the lower limit allowable range than the target value. Turn on. Thereby, the surface temperature of the semiconductor wafer W can be easily controlled to a preset target value.

  As described above, in the third embodiment, the target value of the surface temperature of the semiconductor wafer W is set in advance as a control variable, and based on the measured value of the surface temperature measured by the temperature sensor 28 and the temperature monitor 29, The IGBT controller 21 applies a signal to the gate of the IGBT 96 to switch the IGBT 96 to the on state or the off state so that the surface temperature becomes a preset target value. That is, the surface temperature of the semiconductor wafer W is measured by the temperature sensor 28 and the temperature monitor 29 with a very short sampling time, and the measured value is compared with the target value, and feedback control is performed to control the IGBT 96 so that the two match. Is going.

  For this reason, as in the first embodiment, the surface temperature of the semiconductor wafer W can be easily optimized simply by setting the target value. As a result, the time required for optimizing the control variable related to the light emission of the flash lamp (the surface temperature of the semiconductor wafer W in the third embodiment) can be greatly reduced. Moreover, since the surface temperature of the semiconductor wafer W is stabilized, the reproducibility of the light irradiation heat treatment by the flash lamp FL can be improved.

<Modification>
While the embodiments of the present invention have been described above, the present invention can be modified in various ways other than those described above without departing from the spirit of the present invention. For example, in each of the above embodiments, the upper limit allowable range and the lower limit allowable range are defined for the target value of the control variable, and when the measured value exceeds the upper limit allowable range, the IGBT 96 is turned off and falls below the lower limit allowable range. In some cases, the IGBT 96 is turned on. However, if the measured value is larger than the target value, the IGBT 96 may be turned off, and if smaller than the target value, the IGBT 96 may be turned on. This is synonymous with defining the upper limit allowable range and the lower limit allowable range to be zero in each of the above embodiments.

  Alternatively, after the IGBT 96 is first turned on, simple control may be performed in which the IGBT 96 is simply turned off when the measured value reaches the target value. With such simple control, the configuration of the IGBT control unit 21 can be simplified, and the time required for control can be further shortened.

  In the third embodiment, the control mode may be changed when the measured surface temperature of the semiconductor wafer W exceeds a predetermined threshold temperature. For example, when the measured value is less than the threshold temperature, the same IGBT control as in the third embodiment is performed, and when the measured value exceeds the threshold temperature, the control is performed only to turn off the IGBT 96 when the measured value reaches the target value. May be.

  Alternatively, the trigger voltage may be applied to the trigger electrode 91 by controlling the trigger circuit 97 in synchronization with the IGBT controller 21 turning on the IGBT 96. In this way, it is possible to reliably energize the flash lamp FL when the IGBT 96 is turned on. Particularly when the IGBT 96 is turned on when the off state of the IGBT 96 is long or when the current value flowing through the flash lamp FL is low, it is preferable to apply the trigger voltage to the trigger electrode 91 in synchronization therewith. .

  In each of the above embodiments, the IGBT control unit 21 is a separate element from the control unit 3. However, the control unit 3 may be configured by a computer that can respond and output sufficiently quickly with respect to the input. For example, the function of the IGBT control unit 21 may be realized by the control unit 3.

  Further, in each of the above embodiments, the combination of the time from the start of control and the target value is sequentially input from the input unit 33 to set the time profile of the target value. The operator may input the target value time profile directly from the input unit 33 graphically. Further, the time profile of the target value that has been previously set and stored in the storage unit such as a magnetic disk may be read out, or may be downloaded from the outside of the heat treatment apparatus 1.

  In the above 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, instead of the IGBT 96, another transistor that can turn on and off the circuit according to the signal level input to the gate may be used. However, since a considerable amount of power is consumed for the light emission of the flash lamp FL, it is preferable to employ an IGBT or a GTO (Gate Turn Off) thyristor suitable for handling a large amount of power.

  In the above embodiment, the semiconductor wafer W is preheated by placing it on the hot plate 71. However, the preheating method is not limited to this, and a halogen lamp is provided to provide light. The semiconductor wafer W may be preheated to the preheating temperature T1 by irradiation.

  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 or a solar cell substrate used for a liquid crystal display device or the like. Further, the technique according to the present invention may be applied to bonding of metal and silicon or crystallization of polysilicon.

DESCRIPTION OF SYMBOLS 1 Heat processing apparatus 3 Control part 4 Holding part raising / lowering mechanism 5 Lamphouse 6 Chamber 7 Holding part 21 IGBT control part 25 Current monitor 26 Optical sensor 27 Light quantity monitor 28 Temperature sensor 29 Temperature monitor 32 Target value setting part 33 Input part 60 Upper opening 61 Chamber window 65 Heat treatment space 71 Hot plate 72 Susceptor 91 Trigger electrode 92 Glass tube 93 Capacitor 94 Coil 96 IGBT
97 Trigger circuit FL Flash lamp W Semiconductor wafer

Claims (6)

A heat treatment apparatus for heating a substrate by irradiating the substrate with flash light,
Holding means for holding the substrate;
A flash lamp for irradiating flash light onto the substrate held by the holding means;
An insulated gate bipolar transistor connected in series with the flash lamp, capacitor and coil;
Measuring means for measuring a control variable related to light emission of the flash lamp;
Based on the measured value obtained by the measuring means, a signal is applied to the gate of the insulated gate bipolar transistor to turn the insulated gate bipolar transistor on or off so that the control variable becomes a preset target value. IGBT control means for switching to a state;
Equipped with a,
The control variable is a current value flowing through the flash lamp,
The heat treatment apparatus characterized in that the measuring means is a current monitor for measuring a current value flowing in a circuit including the flash lamp . The heat treatment apparatus according to claim 1, wherein
A heat treatment apparatus, further comprising setting means for setting a time profile of a target value of the control variable. In the heat treatment apparatus according to claim 1 or 2,
The IGBT control means turns off the insulated gate bipolar transistor when the measured value of the control variable is larger than the upper limit allowable range than the target value, and turns off the insulated gate bipolar when the measured value of the control variable is smaller than the lower limit allowable range. A heat treatment apparatus which turns on a transistor. A heat treatment method for heating a substrate by irradiating the substrate with flash light,
A light emitting step of irradiating a flash light from the flash lamp onto a substrate by causing a charge accumulated in the capacitor to flow in a flash lamp connected in series with a capacitor, a coil and an insulated gate bipolar transistor;
A measuring step for measuring a control variable related to light emission of the flash lamp;
Based on the measured value obtained in the measuring step, a signal is applied to the gate of the insulated gate bipolar transistor so that the control variable becomes a preset target value, and the insulated gate bipolar transistor is turned on or An IGBT control step for switching to an off state;
With
The heat treatment method according to claim 1, wherein the control variable is a current value flowing through the flash lamp. The heat treatment method according to claim 4, wherein
A heat treatment method, further comprising a setting step of setting a time profile of a target value of the control variable. In the heat treatment method according to claim 4 or 5,
In the IGBT control step, the insulated gate bipolar transistor is turned off when the measured value of the control variable exceeds the upper limit allowable range beyond the target value, and the insulated gate bipolar when the measured value of the control variable is lower than the lower limit allowable range. A heat treatment method comprising turning on a transistor.

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