JP6096592B2 - Heat treatment equipment - Google Patents

Description

  The present invention relates to a heat treatment apparatus 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 light.

  A flash lamp annealing (FLA) apparatus is used as a heat treatment apparatus for heating the surface of a substrate such as a semiconductor wafer in a very short time. Flash lamp annealing uses a xenon flash lamp (hereinafter referred to simply as a “flash lamp” to mean a xenon flash lamp) to irradiate the surface of the semiconductor wafer with flash light so that only the surface of the semiconductor wafer is exposed. This is a heat treatment technique for raising the temperature in a 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 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. Such flash lamp annealing is suitable for a process that requires a very short time for the wafer surface to reach a target temperature, such as activation of impurities implanted into a semiconductor wafer.

  In Patent Document 1, as a flash lamp annealing apparatus, a flash is applied to a surface of a semiconductor wafer that is placed on a hot plate and preheated to a predetermined temperature from the flash lamp with an irradiation time of 0.1 to 10 milliseconds. An apparatus that irradiates light and instantaneously heats the surface to 1000 ° C. or higher is disclosed.

JP 2010-238735 A

  In the flash lamp annealing apparatus disclosed in Patent Document 1, an O-ring is sandwiched between a quartz chamber window and a chamber, and the chamber window is pressed against the chamber side by a clamp ring (aluminum frame member) from above. The chamber is insulated from the external environment. The atmosphere is controlled so that the oxygen concentration becomes constant or less by always supplying an appropriate amount of nitrogen gas into the chamber. The frame member that presses the chamber window is fastened to the chamber by screws, but the tightening torque is controlled to be constant (for example, 25 cNm) so that the quartz chamber window is not broken too strongly.

  However, as the semiconductor wafers to be produced have become finer, the required particle conditions have become stricter, and stricter atmosphere management has become necessary. For example, in the 40 nm process, the allowable increase in the number of particles per semiconductor wafer during heat treatment was 20 or less particles having a particle size of 0.12 μm or more, but in the finer 28 nm process, 0.06 μm or more. The number of particles is required to be 40 or less.

  For this reason, in order to improve the sealing performance between the chamber window and the chamber, it has been studied to increase the tightening torque for fastening the frame member to the chamber. By increasing the tightening torque and pressing the O-ring more strongly by the chamber window, it is possible to reduce the amount of particles adhering to the semiconductor wafer by reducing a small amount of atmosphere flowing from the external environment into the chamber.

  However, due to the increased tightening torque, a new problem has arisen in that quartz defects occur at the contact portion between the frame member and the chamber window. If a defect occurs in the chamber window, the entire quartz chamber window may break from the defect. On the other hand, the tightening torque must be above a certain level so that severe particle conditions can be satisfied.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a heat treatment apparatus capable of preventing the quartz window from being lost even if the tightening torque for fastening the frame member to the chamber is increased.

In order to solve the above-mentioned problem, the invention of claim 1 is a heat treatment apparatus for heating a substrate by irradiating the substrate with light, a chamber for accommodating the substrate, a quartz window for closing the opening of the chamber, A heating light source for irradiating light into the chamber through a quartz window and a fastening to the chamber so that the other surface of the quartz window is brought into contact with the peripheral portion of the one surface of the quartz window with respect to the chamber A pressing frame member, a first O-ring sandwiched between the peripheral portion of the other surface of the quartz window and the chamber, and an end surface of the quartz window and the chamber and the frame member. with a second O-ring, wherein the frame member is in contact with the peripheral edge also at the inner side than the edge portion of the one surface of the quartz window to the frame When the material is fastened to the chamber, the quartz window presses the first O-ring against the chamber, and the frame member pushes the second O-ring to the end surface of the quartz window and the chamber. It is characterized by pressing against .

  According to a second aspect of the present invention, in the heat treatment apparatus according to the first aspect of the present invention, the end of the frame member facing the inside of the quartz window is isolated from the one surface of the quartz window. To do.

  According to a third aspect of the present invention, in the heat treatment apparatus according to the second aspect of the present invention, the frame member has a contact portion that contacts the peripheral edge portion in an annular plane.

  According to a fourth aspect of the present invention, in the heat treatment apparatus according to the second aspect of the present invention, the frame member has a cross-sectional curved shape and has a contact portion that contacts the peripheral edge at one point of the curved shape. It is characterized by.

  According to a fifth aspect of the present invention, in the heat treatment apparatus according to the second aspect of the present invention, the frame member has a W-shaped cross section and contacts the peripheral edge at two lower ends of the W-shaped. It has a contact part.

According to a sixth aspect of the present invention, in the heat treatment apparatus according to any one of the first to fifth aspects of the present invention, the heating light source includes a pulsed light emitting lamp that emits flash light.

According to the first to sixth aspects of the present invention, the frame member that presses the quartz window against the chamber is in contact with the peripheral edge inside the edge of the one surface of the quartz window. The part is open, and even if the tightening torque for fastening the frame member to the chamber is increased, the quartz window can be prevented from being broken. And a first O-ring sandwiched between the peripheral portion of the other surface of the quartz window and the chamber, and a second O-ring sandwiched between the end surface of the quartz window and the chamber and the frame member. The leak path from the external environment to the inside of the chamber is double-sealed, and the inflow of the external atmosphere containing particles into the chamber can be reliably prevented.

  In particular, according to the second aspect of the present invention, since the end of the frame member is isolated from one surface of the quartz window, it is possible to prevent the end of the frame member from causing a defect in the quartz window.

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 the fragmentary sectional view which expanded the upper end part vicinity of the chamber. It is a top view of the aluminum frame which presses down a chamber window. It is a figure which shows the other example of an aluminum frame. It is a figure which shows the other example of an aluminum frame.

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

  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 heats a semiconductor wafer W by irradiating a disk-shaped semiconductor wafer W as a substrate with flash light irradiation. The size of the semiconductor wafer W to be processed is not particularly limited, and is, for example, φ300 mm or φ450 mm. Impurities are implanted into the semiconductor wafer W before being carried into the heat treatment apparatus 1, and an activation process of the impurities implanted by the heat treatment by the heat treatment apparatus 1 is executed. In FIG. 1 and the subsequent drawings, the size and number of each part are exaggerated or simplified as necessary for easy understanding.

  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. Further, the gas ring 631 on the upper side of the inner side surface of the chamber side portion 63 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, an O-ring is sandwiched between the lower peripheral edge of the chamber window 61 and the chamber side 63 and the aluminum frame 90 is brought into contact with the upper peripheral edge of the chamber window 61 so that the aluminum frame 90 is attached to the chamber side 63. The chamber window 61 is pressed against the O-ring by screwing. The pressing of the chamber window 61 by the aluminum frame 90 will be further described later.

  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 a processing gas (for example, 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 disc-shaped 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. And a holding unit elevating mechanism 4 that elevates the 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 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 includes a hot plate (heating plate) 71 for preheating (so-called assist heating) the semiconductor wafer W and a susceptor 72 installed on the upper surface of the hot plate 71. 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, and a pin 75 for preventing the positional deviation of the semiconductor wafer W is provided on the upper surface thereof. The susceptor 72 is supported on the hot plate 71 with its lower surface brought into 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.

  Returning to FIG. 1, the lamp house 5 is provided above the chamber 6. The lamp house 5 includes a light source including a plurality of (30 in the present embodiment) xenon flash lamps FL and a reflector 52 provided so as to cover the light source inside the housing 51. Composed. 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. The plane area of the plane formed by the arrangement of the plurality of flash lamps FL is at least larger than the semiconductor wafer W held by the holding unit 7.

  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 flows instantaneously in the glass tube, and light is emitted by excitation of atoms or molecules of xenon at that time. 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 100 millisecond. It has the feature that it can irradiate strong light. That is, the flash lamp FL is a pulse light emitting lamp that emits light instantaneously in an extremely short time of less than 1 second. The light emission time of the flash lamp FL can be adjusted by the coil constant of the lamp power source that supplies power to the flash lamp FL.

  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 flash 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. 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.

  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. The processing in the heat treatment apparatus 1 proceeds as the CPU of the control unit 3 executes a predetermined processing program.

  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, the description of the pressing of the chamber window 61 by the aluminum frame 90 will be continued. FIG. 6 is an enlarged partial cross-sectional view of the vicinity of the upper end portion of the chamber 6. An annular groove 67 is formed on the upper surface of the chamber side portion 63 of the chamber 6. An annular O-ring 68 (first O-ring) is fitted into the groove 67. The O-ring 68 is made of, for example, fluororubber (FKM) excellent in heat resistance and chemical resistance, and its maximum specification temperature is about 300 ° C. The diameter of the O-ring 68 (equal to the diameter of the groove 67) is smaller than the diameter of the semiconductor wafer W. In addition, the diameter of the cross section of the O-ring 68 (cross section cut by a plane perpendicular to the circumferential direction) is larger than the depth of the groove 67.

  A quartz disk-shaped chamber window 61 is attached to the chamber 6 with an O-ring 68 interposed therebetween. Specifically, the chamber window 61 is attached to the chamber side portion 63 so that the peripheral edge portion of the lower surface of the chamber window 61 contacts the O-ring 68.

  The O-ring 68 is sandwiched and pressed by the aluminum frame 90 from the upper side of the chamber window 61 attached to the chamber 6. FIG. 7 is a plan view of an aluminum frame 90 that holds the chamber window 61 down. The aluminum frame 90 is an annular member formed of aluminum (Al). As shown in FIG. 6, the aluminum frame 90 includes a fixing portion 91 and a flange portion 92. The flange portion 92 of this embodiment has a cross-sectional shape that is bent at two locations, and includes a distal end portion 93, an intermediate portion 94, and a proximal end portion 95. The flange portion 92 is bent so that the intermediate portion 94 protrudes toward the chamber window 61 side.

  The aluminum frame 90 is fixed to the chamber 6 by fastening the fixing portion 91 to the chamber side portion 63 with the screw 96 while the intermediate portion 94 of the flange portion 92 is in contact with the upper surface of the chamber window 61, and the flange portion 92. Presses the chamber window 61 downward. As shown in FIG. 7, the aluminum frame 90 is fastened to the chamber side portion 63 by twelve screws 96 arranged every 30 ° along the circumferential direction. As the screw 96, for the purpose of improving heat resistance and wear resistance, a stainless steel screw coated with titanium nitride (TiN) is used. In this case, in order to prevent loosening of the screw 96 after fastening, it is desirable to use the screw 96 from which the TiN coating is not removed. Further, the tightening torque when the screw 96 is fastened is controlled to 150 cNm to 300 cNm. Further, a spring washer 97 is inserted when the screw 96 is fastened (FIG. 6). Thereby, it can prevent reliably that the screw | thread 96 loosens.

  By fastening the aluminum frame 90 to the chamber side portion 63 with twelve screws 96 arranged at equal intervals, the flange portion 92 presses the lower surface of the chamber window 61 against the chamber 6 with equal pressure. Since an O-ring 68 is sandwiched between the lower surface of the chamber window 61 and the chamber side 63 of the chamber 6, when the flange 92 of the aluminum frame 90 presses the chamber window 61 downward, the O-ring 68 is deformed. And compressed. As a result, the space between the lower peripheral edge of the chamber window 61 and the chamber side 63 is sealed. Since the tightening torque of the screw 96 for fastening the aluminum frame 90 to the chamber 6 is 150 cNm to 300 cNm, which is significantly stronger than the conventional (25 cNm), the sealing performance between the chamber window 61 and the chamber 6 can be improved. Since the chamber window 61 is fastened to the chamber side 63 by screws 96 at 12 positions with the O-ring 68 interposed therebetween, the lower surface of the chamber window 61 does not directly contact the chamber side 63 even after fastening.

  As clearly shown in FIGS. 6 and 7, the aluminum frame 90 is in contact with the peripheral edge portion of the upper surface of the chamber window 61 by an intermediate portion 94 that is an annular plane. The distal end portion 93 and the proximal end portion 95 of the aluminum frame 90 are not in contact with the upper surface of the chamber window 61. As shown in FIG. 6, the intermediate portion 94 of the aluminum frame 90 is in contact with the peripheral portion on the inner side of the edge portion 61 a on the upper surface of the chamber window 61. Therefore, the flange portion 92 of the aluminum frame 90 is not in contact with the edge portion 61a on the upper surface of the chamber window 61, and the edge portion 61a is open. When the screw 96 is fastened by a strong tightening torque, the base end portion 95 of the flange 92 may be deformed, but the flange 92 still contacts the edge 61a of the upper surface of the chamber window 61. Is not reached.

  Further, as shown in FIG. 6, the inner front end of the front end portion 93, that is, the end portion of the flange portion 92 of the aluminum frame 90 facing the inner side of the chamber window 61 is isolated from the upper surface of the chamber window 61. That is, since the flange portion 92 is bent so that the intermediate portion 94 protrudes toward the chamber window 61 from the distal end portion 93 and the base end portion 95, the end edge portion 61 a on the upper surface of the chamber window 61 is formed on the aluminum frame 90. While not contacting, the inner end of the flange 92 of the aluminum frame 90 is not in contact with the chamber window 61.

  In the heat treatment apparatus 1 of the present embodiment, in addition to the O-ring 68, an end face of the chamber window 61 and an O-ring 69 (second O-ring) sandwiched between the chamber 6 and the aluminum frame 90 are provided. . Similar to the O-ring 68, the O-ring 69 is made of, for example, fluoro rubber (FKM). The diameter of the O-ring 69 is larger than the diameter of the O-ring 68.

  An annular holding metal fitting 98 is fixed inside the fixing portion 91 of the aluminum frame 90. The cross-sectional shape of the presser fitting 98 is L-shaped. An O-ring 69 is sandwiched between the presser fitting 98 and the end surface of the chamber window 61 and the upper surface of the chamber side portion 63, and the aluminum frame 90 is fastened by screws 96. Thereby, the O-ring 69 is deformed and compressed, and the space between the O-ring 69 and the end surface of the chamber window 61 and the space between the O-ring 69 and the upper surface of the chamber side portion 63 are sealed.

  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 (flash lamp 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, after the holding unit 7 is lowered to the delivery position, the valve 82 is opened, and an inert gas (in this embodiment, nitrogen gas) is supplied into the heat treatment space 65 of the chamber 6. At the same time, the valve 87 is opened and the gas in the heat treatment space 65 is exhausted. Nitrogen gas supplied to the chamber 6 flows from the gas introduction buffer 83 in the direction of the arrow AR4 shown in FIG. 2 in the heat treatment space 65, and is exhausted by the exhaust mechanism through the exhaust path 86 and the valve 87. A part of the nitrogen gas supplied to the chamber 6 is also discharged from an outlet (not shown) provided inside the bellows 47.

  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. 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 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.

  Preheating for about 60 seconds is performed at this 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 600 ° 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. Further, 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 about 60 seconds elapses, flash light is irradiated 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 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 holding part 7 in the chamber 6, and the other part is once reflected by the reflector 52 and then goes into the chamber 6. Flash heating of the semiconductor wafer W is performed by 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 into a light pulse having a very short electrostatic energy stored in advance, and the irradiation time is about 0.1 milliseconds to 100 milliseconds. It is a very 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 the processing temperature T2, and after the impurities implanted into the semiconductor wafer W are activated, the surface temperature is increased. It descends 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 the impurities injected into the semiconductor wafer W due to heat. Can do. Since the time required for the activation of impurities is extremely short compared to the time required for the thermal diffusion, the activation is possible even in a short time in which diffusion of about 0.1 millisecond to 100 millisecond does not occur. Complete.

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

  After the flash heating is finished and the standby for about 10 seconds at the processing position, the holding unit 7 is lowered again to the delivery position shown in FIG. 1 by the holding unit lifting mechanism 4, and the semiconductor wafer W is transferred from the holding unit 7 to the support pins 70. Is passed. 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.

  In the present embodiment, the O-ring 68 is sandwiched and pressed by the aluminum frame 90 from the upper side of the chamber window 61 mounted on the chamber 6, but the edge 61 a on the upper surface of the chamber window 61 is attached to the aluminum frame 90. The 90 flange portions 92 are not in contact with each other, and the end edge portion 61a is open. For this reason, even if the tightening torque for fastening the aluminum frame 90 to the chamber 6 is significantly increased from 150 cNm to 300 cNm as compared with the conventional case, the end edge portion 61 a of the chamber window 61 is not damaged. Therefore, it is possible to prevent the entire chamber window 61 from being cracked starting from the missing edge 61a.

  On the other hand, the intermediate portion 94 of the flange portion 92 of the aluminum frame 90 is in contact with the upper surface peripheral portion on the inner side of the end edge portion 61a of the chamber window 61 in an annular plane. Compared to the edge portion 61a which is a corner portion, the flat upper surface peripheral portion on the inner side is less likely to be damaged even if the flange portion 92 is in contact with the edge portion 61a. That is, even if the tightening torque for fastening the aluminum frame 90 to the chamber 6 is increased by bringing the aluminum frame 90 into contact with the peripheral edge of the upper surface inside the edge 61a of the quartz chamber window 61, the quartz chamber window The loss of 61 can be prevented.

  From the opposite viewpoint, since the quartz chamber window 61 is less likely to be damaged, the tightening torque for fastening the aluminum frame 90 to the chamber 6 can be made significantly stronger than before. As a result, the sealing property between the chamber window 61 and the chamber 6 by the O-ring 68 is enhanced, the atmosphere leaking into the chamber 6 from the external environment is minimized, and the number of particles adhering to the semiconductor wafer W during flash heating is reduced. Can be reduced.

  Further, the end portion of the flange portion 92 of the aluminum frame 90 may be damaged by contacting the upper surface of the chamber window 61, but in this embodiment, the aluminum frame is directed toward the inside of the chamber window 61. The end portion of the 90 flange portion 92 is also isolated from the upper surface of the chamber window 61. For this reason, there is no possibility that the end portion of the flange 92 may cause a defect in the quartz chamber window 61. Therefore, the quartz chamber window 61 can be more reliably prevented from being damaged.

  Further, in the heat treatment apparatus 1 of the present embodiment, in addition to the O-ring 68, an O-ring 69 sandwiched between the end surface of the chamber window 61 and the chamber 6 and the aluminum frame 90 is provided. The O-ring 69 is deformed when the aluminum frame 90 is fastened to the chamber 6, and seals between the O-ring 69 and the end surface of the chamber window 61 and between the O-ring 69 and the upper surface of the chamber side portion 63. .

  In the case where only the O-ring 68 is provided, the main leak path of the chamber 6 is between the chamber window 61 and the chamber side portion 63 from the gap between the fixed portion 91 of the aluminum frame 90 and the upper surface of the chamber side portion 63. (See FIG. 6). A small amount of the external atmosphere containing particles flows into the heat treatment space 65 in the chamber 6 through this path. Although the space between the chamber window 61 and the chamber side portion 63 is sealed by an O-ring 68, it may not always be sufficient for severe particle conditions required in recent years. In the present embodiment, in addition to the O-ring 68, an O-ring 69 is provided to seal between the O-ring 69 and the upper surface of the chamber side portion 63. That is, the above leakage path is double-sealed by the O-ring 68 and the O-ring 69. As a result, the leak path is reliably sealed, and the inflow of the external atmosphere containing particles into the chamber 6 can be reliably prevented. As a result, the number of particles adhering to the semiconductor wafer W during flash heating can be reduced to satisfy severe particle conditions that have recently been demanded.

  Further, when the end portion of the flange 92 of the aluminum frame 90 is isolated from the upper surface of the chamber window 61 as in the present embodiment, an external atmosphere flows from between the flange 92 and the upper surface of the chamber window 61. It is also possible. For this path, an O-ring 69 seals between the O-ring 69 and the end face of the chamber window 61. Thereby, even if the external atmosphere flows from between the flange 92 and the upper surface of the chamber window 61, the external atmosphere does not flow beyond the seal portion between the O-ring 69 and the end surface of the chamber window 61. In addition, the inflow of the external atmosphere containing particles into the chamber 6 can be more reliably prevented.

  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, the shape of the aluminum frame 90 may be as shown in FIG. 8 or FIG.

  An aluminum frame 190 shown in FIG. 8 includes a fixing portion 191 and a flange portion 192. The fixing part 191 is the same as the fixing part 91 of the aluminum frame 90 of the above embodiment. The flange portion 192 has a curved cross-sectional shape that curves so as to protrude toward the chamber window 61 side. Then, the aluminum frame 190 in FIG. 8 contacts the peripheral edge of the upper surface of the chamber window 61 at one point of the curved shape of the curved flange 192 cross section. Therefore, the aluminum frame 190 in FIG. 8 comes into contact with the peripheral edge of the upper surface of the chamber window 61 by an annular curve (circle). Even with the aluminum frame 190 having such a shape, the same effect as that of the above-described embodiment can be obtained when the flange portion 192 presses the chamber window 61.

  Further, the aluminum frame 290 shown in FIG. 9 includes a fixing portion 291 and a flange portion 292. The fixing portion 291 is the same as the fixing portion 91 of the aluminum frame 90 of the above embodiment. As shown in FIG. 9, the flange portion 292 has a W-shaped cross section. The aluminum frame 290 in FIG. 9 contacts the peripheral edge of the upper surface of the chamber window 61 at two points at the lower end of the W-shaped cross section of the flange portion 192. Therefore, the aluminum frame 290 of FIG. 9 comes into contact with the peripheral edge portion of the upper surface of the chamber window 61 by two circular curves (circles) having different diameters. Even in the case of the aluminum frame 290 having such a shape, the same effect as that of the above embodiment can be obtained by pressing the chamber window 61 by the flange portion 292.

  Further, in the above embodiment, the O-ring 69 is pressed by the presser fitting 98 having an L-shaped cross section, but the force acting on the O-ring 69 from the presser fitting 98 by fastening the aluminum frame 90 is mainly in the vertical direction. Therefore, when the horizontal force is not sufficient, the holding metal fitting 98 may be pressed in the horizontal direction with a screw that penetrates the fixing portion 91 in the horizontal direction. In the case where such horizontal screws are provided, it goes without saying that the aluminum frame 90 is provided at a position where it is not buffered with the screws 96 that are fastened to the chamber 6. Further, it is preferable to provide a plurality of horizontal screws at equal intervals so that the entire circumference of the presser fitting 98 can be pressed uniformly.

  Further, the number of screws 96 for fastening the aluminum frame 90 to the chamber 6 is not limited to twelve, but may be an appropriate number. However, in order for the aluminum frame 90 to press the chamber window 61 with an equal pressure, the number of screws 96 is preferably six or more.

  Further, instead of the aluminum frame 90, a frame member made of another material such as stainless steel may be used.

  In the above embodiment, the semiconductor wafer W is preheated by the hot plate 71 of the holding unit 7. Instead, a halogen lamp is provided below the chamber 6, and light irradiation from the halogen lamp is performed. Thus, the semiconductor wafer W may be preheated. In this case, a quartz window for transmitting light from the halogen lamp is also provided on the lower side of the chamber 6, so that the quartz window is prevented from being broken by applying the same technique as in the above embodiment. be able to.

  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.

  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 flat panel display such as a liquid crystal display device. 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 Lamp house 6 Chamber 7 Holding part 60 Upper opening 61 Chamber window 63 Chamber side part 65 Heat processing space 68,69 O-ring 71 Hot plate 72 Susceptor 90,190,290 Aluminum frame 91 , 191, 291 Fixing part 92, 192, 292 Gutter part 93 Tip part 94 Intermediate part 95 Base end part 96 Screw 97 Spring washer 98 Press fitting FL Flash lamp W Semiconductor wafer

Claims (6)

A heat treatment apparatus for heating a substrate by irradiating the substrate with light,
A chamber for housing the substrate;
A quartz window closing the opening of the chamber;
A heating light source that irradiates light into the chamber through the quartz window;
By being fastened to the chamber, a frame member that contacts the peripheral portion of one surface of the quartz window and presses the other surface of the quartz window against the chamber;
A first O-ring sandwiched between a peripheral portion of the other surface of the quartz window and the chamber;
A second O-ring sandwiched between an end face of the quartz window and the chamber and the frame member;
With
The frame member is in contact with the peripheral edge inside the edge of the one surface of the quartz window ,
When the frame member is fastened to the chamber, the quartz window presses the first O-ring against the chamber, and the frame member pushes the second O-ring to the end surface of the quartz window and A heat treatment apparatus that presses against the chamber . The heat treatment apparatus according to claim 1, wherein
An end portion of the frame member facing the inside of the quartz window is isolated from the one surface of the quartz window. The heat treatment apparatus according to claim 2,
The said frame member has a contact part which contacts the said peripheral part in a cyclic | annular plane, The heat processing apparatus characterized by the above-mentioned. The heat treatment apparatus according to claim 2,
The said frame member has a contact part which has a cross-sectional curve shape and contacts the said peripheral part at one point of the said curve shape. The heat treatment apparatus according to claim 2,
The said frame member has a contact part which contacts the said peripheral part at two points | pieces of the lower end of the said W-shape which has a W-shaped cross section. In the heat processing apparatus in any one of Claims 1-5 ,
The heat treatment apparatus is characterized in that the heating light source includes a pulsed light emitting lamp for irradiating flash light.

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