JP5731230B2 - 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.

  Conventionally, a lamp annealing apparatus using a halogen lamp has been generally used in an impurity (ion) activation process of a semiconductor wafer after ion implantation. Further, in recent years, a flash lamp using xenon or the like is used to irradiate the surface of a semiconductor wafer with flash light, so that only the surface of the semiconductor wafer into which ions have been implanted is exposed in 1100 in a very short time (several milliseconds or less). Techniques for raising the temperature to about ℃ have been proposed. Furthermore, a technique has been proposed in which a xenon flash lamp and a halogen lamp are used in combination, and the semiconductor wafer is preheated to a predetermined temperature with a halogen lamp before flash heating with the xenon flash lamp.

  By the way, in such a heating mechanism using a halogen lamp, in a configuration in which rod-shaped halogen lamps are arranged at equal intervals, for example, the illuminance tends to be lower at the peripheral portion than at the central portion of the semiconductor wafer. There was a problem in the temperature uniformity of the treatment. Therefore, as disclosed in Patent Document 1, halogen lamps are arranged at high density in a region corresponding to the peripheral portion of the semiconductor wafer, or the halogen lamp in the region corresponding to the peripheral portion of the semiconductor wafer has higher output. Thus, a configuration has been proposed in which a larger amount of light is applied to the peripheral portion of the semiconductor wafer by such measures as controlling the power supply.

  However, if a configuration in which a larger amount of light is applied to the peripheral edge of the semiconductor wafer in this way is taken, the uniformity of the temperature of the entire substrate will be improved, but this time on the peripheral edge side of the semiconductor wafer. In some cases, a peak at which the temperature rises may appear, and further improvement has been demanded.

JP 2009-260061 A JP 2002-110580 A JP 2003-31517 A

  As described in Patent Document 2, if a light diffusing plate is provided over the whole so as to partition the light source and the semiconductor wafer, the illuminance distribution is improved, but the illuminance is also lowered over the whole, and heating is performed. Efficiency will fall and temperature will become low or will require long time for a heating. In addition, as described in Patent Document 3, in a configuration in which a lens group in which a plurality of lenses having different light collection degrees are arranged two-dimensionally between a light source and a semiconductor wafer, a plurality of lenses having different light collection degrees are appropriately laid out. Therefore, it must be arranged and fixed, and it is difficult to manufacture and expensive.

  The present invention has been made in view of the above problems, and has an object to provide a heat treatment apparatus that is easy to manufacture and inexpensive, and that improves the uniformity of the illuminance distribution without reducing the overall illuminance. .

The invention described in claim 1 is a heat treatment apparatus for heating a substrate by irradiating the substrate with light, and has a supporting means for supporting the substrate and a light emitting region surface having a shape larger than that of the substrate. A light source structure that irradiates light with the light emitting region surface facing the substrate supported by the support means, and a cylindrical shape between the substrate supported by the support means and the light source structure. And a translucent light scattering member configured to transmit a part of the incident light and scatter a part thereof , and the light source structure has a peripheral portion rather than a central portion of the light emitting region surface. In this case, a plurality of halogen lamps are arranged so as to increase the amount of emitted light per unit area, and the light scattering member scatters light from the peripheral portion of the light source structure .

The invention according to claim 2 is the heat treatment apparatus according to claim 1, wherein the light scattering member is closer to the light source structure than an intermediate between the light source structure and the substrate supported by the support means. It is characterized by being arranged in .

  According to a third aspect of the present invention, in the heat treatment apparatus according to the first or second aspect, the substrate is a semiconductor wafer, and the bottomless cylinder in which the light scattering member is disposed coaxially with the semiconductor wafer. It is characterized by its shape.

  According to a fourth aspect of the present invention, in the heat treatment apparatus according to the third aspect, the cylindrical shape of the light scattering member is substantially the same as the diameter of the semiconductor wafer.

  According to a fifth aspect of the present invention, in the heat treatment apparatus according to any one of the first to fourth aspects, the light scattering member is made of a glass material on which a fine structure for light scattering is formed. .

According to a sixth aspect of the present invention, in the heat treatment apparatus according to any one of the first to fifth aspects, the light source structure includes a light source group including a plurality of rod-shaped halogen lamps arranged in parallel. It is characterized by.

According to the first aspect of the present invention, a cylindrical light in which a part of the light emitted from the light source structure having a light emitting area surface having a shape larger than that of the substrate is disposed between the substrate and the light source structure. Since it is scattered by the scattering member, it is easy to manufacture and inexpensive, and the uniformity of the illuminance distribution can be improved without reducing the overall illuminance. In addition, light with a large amount of emitted light per unit area is irradiated from the peripheral part of the light source structure, but the peak of illuminance at the peripheral part of the substrate becomes low due to scattering by the light scattering member near the peripheral part of the light source structure, Distribution uniformity can be improved.

According to the third and fourth aspects of the present invention, the light passing through the central portion is transmitted by the bottomless cylindrical light scattering member, so that it is not scattered and a part of the light passing through the peripheral portion is not scattered. Scattered, the light peak at the periphery of the substrate is lowered, and the uniformity of the illuminance distribution can be improved.
Thus, it is possible to easily arrange the mounting angles, and to produce an illumination device and an inspection device that are easy to manufacture, highly efficient, and have good uniformity.

  According to invention of Claim 5, a light-scattering member can be easily manufactured with the glass material in which the microstructure for light scattering was formed.

According to invention of Claim 6, a light source structure can be easily manufactured with the light source group which consists of a some rod-shaped halogen lamp arrange | positioned in parallel.

It is a longitudinal cross-sectional view which shows the structure of the heat processing apparatus which concerns on this invention. It is a perspective view of a holding part. It is a top view of a holding plate. It is the figure which expanded the bump vicinity when a semiconductor wafer was mounted in the holding plate. It is a top view of a transfer mechanism. It is a side view of a transfer mechanism. It is a top view which shows arrangement | positioning of a some halogen lamp. It is a schematic diagram which shows the positional relationship of a semiconductor wafer, a halogen lamp, and a louver. It is a figure which shows a louver and a support body. It is a schematic diagram which shows the positional relationship of a halogen lamp and a louver. It is a figure which shows the drive circuit of a flash lamp. It is a figure which shows the illumination intensity distribution on a semiconductor wafer.

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

    <1. Overall configuration>

  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 of the present embodiment is a flash lamp annealing apparatus that heats a semiconductor wafer W having a diameter of 300 mm as a substrate by irradiating the semiconductor wafer W with light. Impurities are implanted into the semiconductor wafer W before being carried into the heat treatment apparatus 1, and activation processing of the implanted impurities by the heat treatment by the heat treatment apparatus 1 is executed.

  The heat treatment apparatus 1 includes a chamber 6 that accommodates a semiconductor wafer W, a flash heating unit 5 that houses a plurality of flash lamps FL, and a halogen heating unit 4 that houses a plurality of halogen lamps HL. A flash heating unit 5 is provided on the upper side of the chamber 6, and a halogen heating unit 4 is provided on the lower side. Further, the heat treatment apparatus 1 includes a holding unit 7 that holds the semiconductor wafer W in a horizontal position inside the chamber 6, a transfer mechanism 10 that transfers the semiconductor wafer W between the holding unit 7 and the outside of the apparatus, Is provided. Further, the heat treatment apparatus 1 includes a control unit 3 that controls the operation mechanisms provided in the halogen heating unit 4, the flash heating unit 5, and the chamber 6 to perform the heat treatment of the semiconductor wafer W.

  The chamber 6 is configured by mounting quartz chamber windows above and below a cylindrical chamber side portion 61. The chamber side portion 61 has a substantially cylindrical shape with upper and lower openings. The upper opening is closed by an upper chamber window 63 and the lower opening is closed by a lower chamber window 64. ing. The upper chamber window 63 constituting the ceiling of the chamber 6 is a disk-shaped member made of quartz, and functions as a quartz window that transmits light emitted from the flash heating unit 5 into the chamber 6. The lower chamber window 64 constituting the floor portion of the chamber 6 is also a disk-shaped member made of quartz and functions as a quartz window that transmits light from the halogen heating unit 4 into the chamber 6.

  A reflection ring 68 is attached to the upper part of the inner wall surface of the chamber side part 61, and a reflection ring 69 is attached to the lower part. The reflection rings 68 and 69 are both formed in an annular shape. The upper reflecting ring 68 is attached by fitting from above the chamber side portion 61. On the other hand, the lower reflection ring 69 is mounted by being fitted from the lower side of the chamber side portion 61 and fastened with a screw (not shown). That is, the reflection rings 68 and 69 are both detachably attached to the chamber side portion 61. An inner space of the chamber 6, that is, a space surrounded by the upper chamber window 63, the lower chamber window 64, the chamber side portion 61, and the reflection rings 68 and 69 is defined as a heat treatment space 65.

  By attaching the reflection rings 68 and 69 to the chamber side portion 61, a recess 62 is formed on the inner wall surface of the chamber 6. That is, a recess 62 surrounded by a central portion of the inner wall surface of the chamber side portion 61 where the reflection rings 68 and 69 are not mounted, a lower end surface of the reflection ring 68, and an upper end surface of the reflection ring 69 is formed. . The recess 62 is formed in an annular shape along the horizontal direction on the inner wall surface of the chamber 6, and surrounds the holding portion 7 that holds the semiconductor wafer W.

  The chamber side portion 61 and the reflection rings 68 and 69 are formed of a metal material (for example, stainless steel) having excellent strength and heat resistance. Further, the inner peripheral surfaces of the reflection rings 68 and 69 are mirrored by electrolytic nickel plating.

  The chamber side 61 is formed with a transfer opening (furnace port) 66 for carrying the semiconductor wafer W into and out of the chamber 6. The transfer opening 66 communicates from the outside of the chamber 6 to the recess 62 through the chamber side 61. The transfer opening 66 can be opened and closed by a gate valve 185. For this reason, when the gate valve 185 opens the transfer opening 66, the semiconductor wafer W is loaded into the heat treatment space 65 through the recess 62 from the transfer opening 66 and the semiconductor wafer W is unloaded from the heat treatment space 65. It can be performed. Further, when the gate valve 185 closes the transfer opening 66, the heat treatment space 65 in the chamber 6 becomes a sealed space.

Further, a gas supply hole 81 for supplying a processing gas (nitrogen gas (N ₂ ) in the present embodiment) to the heat treatment space 65 is formed in the upper portion of the inner wall of the chamber 6. The gas supply hole 81 is formed at a position above the recess 62 and may be provided in the reflection ring 68. The gas supply hole 81 is connected to a gas supply pipe 83 through a buffer space 82 formed in an annular shape inside the side wall of the chamber 6. The gas supply pipe 83 is connected to a nitrogen gas supply source 85. A valve 84 is inserted in the middle of the path of the gas supply pipe 83. When the valve 84 is opened, nitrogen gas is supplied from the nitrogen gas supply source 85 to the buffer space 82. The nitrogen gas flowing into the buffer space 82 flows so as to expand in the buffer space 82 having a smaller fluid resistance than the gas supply hole 81 and is supplied from the gas supply hole 81 into the heat treatment space 65.

  On the other hand, a gas exhaust hole 86 for exhausting the gas in the heat treatment space 65 is formed in the lower portion of the inner wall of the chamber 6. The gas exhaust hole 86 is formed at a position lower than the recess 62 and may be provided in the reflection ring 69. The gas exhaust hole 86 is connected to a gas exhaust pipe 88 through a buffer space 87 formed in an annular shape inside the side wall of the chamber 6. The gas exhaust pipe 88 is connected to the exhaust unit 190. A valve 89 is inserted in the middle of the path of the gas exhaust pipe 88. When the valve 89 is opened, the gas in the heat treatment space 65 of the chamber 6 is discharged from the gas exhaust hole 86 to the gas exhaust pipe 88 through the buffer space 87. A plurality of gas supply holes 81 and gas exhaust holes 86 may be provided along the circumferential direction of the chamber 6 or may be slit-shaped. Further, the nitrogen gas supply source 85 and the exhaust unit 190 may be a mechanism provided in the heat treatment apparatus 1 or may be a utility of a factory where the heat treatment apparatus 1 is installed.

  A gas exhaust pipe 191 that exhausts the gas in the heat treatment space 65 is also connected to the tip of the transfer opening 66. The gas exhaust pipe 191 is connected to the exhaust unit 190 via a valve 192. By opening the valve 192, the gas in the heat treatment space 65 of the chamber 6 is also exhausted through the transfer opening 66.

    <2. Holding unit 7 and transfer mechanism 10>

  FIG. 2 is a perspective view of the holding unit 7. The holding unit 7 includes a susceptor 70 and a holding plate 74. The susceptor 70 is made of quartz, and is configured such that a plurality of claw portions 72 (four in this embodiment) are erected on an annular ring portion 71. FIG. 3 is a plan view of the holding plate 74. The holding plate 74 is a circular flat plate member made of quartz, and is supported above the susceptor 70 by a claw portion 72 and a support rod 73 described later. The diameter of the holding plate 74 is larger than the diameter of the semiconductor wafer W. That is, the holding plate 74 has a larger planar size than the semiconductor wafer W. A plurality of bumps 75 are erected on the upper surface of the holding plate 74. In the present embodiment, a total of six bumps 75 are erected every 60 ° along a circumference that is concentric with the outer circumference of the holding plate 74. The diameter of the circle in which the six bumps 75 are arranged (the distance between the opposing bumps 75) is smaller than the diameter of the semiconductor wafer W, and in this embodiment is φ280 mm. Each bump 75 is a support pin made of quartz. The number of bumps 75 is not limited to six, and may be three or more that can stably support the semiconductor wafer W.

  On the upper surface of the holding plate 74, a plurality of (five in the present embodiment) guide pins 76 (not shown in FIG. 2) are provided concentrically with the six bumps 75. The diameter of the circle in which the five guide pins 76 are arranged is slightly larger than the diameter of the semiconductor wafer W. Each guide pin 76 is made of quartz.

  By placing the ring portion 71 on the bottom surface of the recess 62, the susceptor 70 of the holding portion 7 is mounted in the heat treatment space 65 of the chamber 6. The holding plate 74 is mounted and held on the claw portion 72 of the susceptor 70 mounted on the chamber 6. The semiconductor wafer W carried into the chamber 6 is placed in a horizontal posture on the holding plate 74 held by the susceptor 70.

  FIG. 4 is an enlarged view of the vicinity of the bump 75 when the semiconductor wafer W is placed on the holding plate 74. A support rod 73 is erected on each claw portion 72 of the susceptor 70. When the upper end portion of the support rod 73 is fitted into a recess formed in the lower surface of the holding plate 74, the holding plate 74 is held by the susceptor 70 without being displaced.

  Further, the bump 75 and the guide pin 76 are also erected by being fitted into a recess formed in the upper surface of the holding plate 74. The upper ends of the bumps 75 and the guide pins 76 erected on the upper surface of the holding plate 74 protrude from the upper surface. The semiconductor wafer W is supported by point contact by a plurality of bumps 75 standing on the holding plate 74 and placed on the holding plate 74. The distance from the height position of the upper end of the bump 75 to the upper surface of the holding plate 74 is 0.5 mm or more and 3 mm or less (1 mm in this embodiment). Therefore, the semiconductor wafer W is supported by the plurality of bumps 75 with an interval of 0.5 mm or more and 3 mm or less from the upper surface of the holding plate 74. Further, the height position of the upper end of the guide pin 76 is higher than the upper end of the bump 75, and the horizontal displacement of the semiconductor wafer W is prevented by the plurality of guide pins 76. The bump 75 and the guide pin 76 may be processed with quartz integrally with the holding plate 74. Further, in place of the plurality of guide pins 76, an annular member formed with a tapered surface having a predetermined angle with the horizontal surface is provided so as to expand upward, and the horizontal displacement of the semiconductor wafer W is thus provided. You may make it prevent.

  A region facing the semiconductor wafer W supported by at least the plurality of bumps 75 on the upper surface of the holding plate 74 is a flat surface. In this case, the semiconductor wafer W is supported by a plurality of bumps 75 at an interval of 0.5 mm or more and 3 mm or less from the plane of the holding plate 74.

  As shown in FIGS. 2 and 3, the holding plate 74 has an opening 78 and a notch 77 penetrating vertically. The notch 77 is provided to pass the probe tip of the contact thermometer 130 using a thermocouple. On the other hand, the opening 78 is provided for receiving radiation light (infrared light) emitted from the lower surface of the semiconductor wafer W held by the holding plate 74 by the radiation thermometer 120.

  FIG. 5 is a plan view of the transfer mechanism 10. FIG. 6 is a side view of the transfer mechanism 10. The transfer mechanism 10 includes two transfer arms 11. The transfer arm 11 has an arc shape that follows the generally annular recess 62. Two lift pins 12 are erected on each transfer arm 11. Each transfer arm 11 can be rotated by a horizontal movement mechanism 13. The horizontal movement mechanism 13 includes a transfer operation position (a solid line position in FIG. 5) for transferring the pair of transfer arms 11 to the holding unit 7 and the semiconductor wafer W held by the holding unit 7. It is moved horizontally between the retracted positions (two-dot chain line positions in FIG. 5) that do not overlap in plan view. As the horizontal movement mechanism 13, each transfer arm 11 may be rotated by an individual motor, or a pair of transfer arms 11 may be interlocked by a single motor using a link mechanism. It may be moved.

  The pair of transfer arms 11 are moved up and down together with the horizontal moving mechanism 13 by the lifting mechanism 14. When the elevating mechanism 14 raises the pair of transfer arms 11 at the transfer operation position, a total of four lift pins 12 pass through the through holes 79 (see FIGS. 2 and 3) formed in the holding plate 74, The upper end of the lift pin 12 protrudes from the upper surface of the holding plate 74. On the other hand, when the elevating mechanism 14 lowers the pair of transfer arms 11 at the transfer operation position, the lift pins 12 are extracted from the through holes 79, and the horizontal movement mechanism 13 moves the pair of transfer arms 11 so as to open each of them. The transfer arm 11 moves to the retracted position. The retracted position of the pair of transfer arms 11 is directly above the ring portion 71 of the susceptor 70. Since the ring portion 71 is placed on the bottom surface of the recess 62, the retracted position of the transfer arm 11 is inside the recess 62. Note that an exhaust mechanism (not shown) is also provided in the vicinity of the portion where the drive unit (the horizontal movement mechanism 13 and the lifting mechanism 14) of the transfer mechanism 10 is provided, and the atmosphere around the drive unit of the transfer mechanism 10 Is discharged to the outside of the chamber 6.

    <3. Flash heating unit 5>

  Returning to FIG. 1, the flash heating unit 5 provided above the chamber 6 includes a light source including a plurality of (30 in the present embodiment) xenon flash lamps FL inside the housing 51, and an upper part of the light source. And a reflector 52 provided so as to cover. A lamp light emission window 53 is mounted on the bottom of the casing 51 of the flash heating unit 5. The lamp light emission window 53 constituting the floor of the flash heating unit 5 is a plate-like quartz window made of quartz. By installing the flash heating unit 5 above the chamber 6, the lamp light emission window 53 faces the upper chamber window 63. The flash lamp FL irradiates the heat treatment space 65 with flash light from above the chamber 6 through the lamp light emission window 53 and the upper chamber window 63.

  Each of the plurality of flash lamps FL is a rod-shaped lamp having a long cylindrical shape, and is located at a position directly above the semiconductor wafer W held by the holding unit 7 along its main surface (that is, along the horizontal direction). ) They are arranged in a plane so that their longitudinal directions are parallel to each other. Therefore, the plane formed by the arrangement of the flash lamps FL is also a horizontal plane.

  FIG. 10 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 a switching element 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.

  In the present embodiment, an insulated gate bipolar transistor (IGBT) is used as the switching element 96. The IGBT 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. A pulse signal is applied from the pulse generator 31 of the control unit 3 to the gate of the switching element 96.

  Even when a pulse is output to the gate of the switching element 96 with the capacitor 93 charged and a high voltage is applied to both ends of the glass tube 92, the xenon gas is normally an insulator, so In this state, electricity does not flow in the glass 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.

  Further, the reflector 52 of FIG. 1 is provided above the plurality of flash lamps FL so as to cover all of them. The basic function of the reflector 52 is to reflect the 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.

    <4. Halogen heating unit 4>

  The halogen heating unit 4 provided below the chamber 6 irradiates light to the heat treatment space 65 from below the chamber 6 through the lower chamber window 64. 7, a light source structure LS configured by arranging a plurality of (40 in this embodiment) halogen lamps HL at a position directly below the semiconductor wafer W held by the semiconductor wafer W, and the light source structure LS and the semiconductor wafer W And a louver 100 disposed between the two.

  7 is a plan view showing the arrangement of the plurality of halogen lamps HL of the light source structure LS, FIG. 8 is a schematic view showing the arrangement of the semiconductor wafer W, the halogen lamp HL, and the like, and FIG. 9 is a plan view showing how the louver 100 is attached. FIG. 10 is a schematic view showing the positional relationship between the louver 4 and the halogen lamp HL. The light source structure LS includes an upper lamp row UHL in which 20 halogen lamps HL are arranged in parallel, and a lower lamp row LHL in which 20 halogen lamps HL are arranged in parallel at a position immediately below the upper lamp row UHL. The halogen lamps HL constituting them are rod-shaped lamps having a cylindrical shape of about 50 cm in length, all having the same characteristics. Each of the upper lamp row UHL and the lower lamp row LHL is configured by arranging 20 halogen lamps HL in parallel in a region of 40 cm × 50 cm in a horizontal plane as will be described later.

  The halogen lamps HL constituting the upper lamp row UHL and the halogen lamps HL constituting the lower lamp row LHL are arranged in a direction orthogonal to each other so that the central portions thereof overlap each other in plan view. By arranging them in a direction orthogonal to each other, unevenness in illuminance caused by the lamp arrangement is prevented or reduced. A 40 cm square region where the upper lamp row UHL and the lower lamp row LHL overlap in plan view is hereinafter referred to as a lamp arrangement region LA. The lamp arrangement area LA is larger than the disk-shaped semiconductor wafer W having a diameter of 300 mm to be processed, and the center of the lamp arrangement area LA is located immediately below the center of the semiconductor wafer W held by the holding unit 7. Are arranged as follows. The upper surface of the lamp arrangement region LA is a light emitting region surface that contributes to the heating of the semiconductor wafer W.

  Further, as shown in FIG. 7, in each of the upper lamp row UHL and the lower lamp row LHL, six of the 20 halogen lamps HL constituting each of the upper lamp row UHL and the lower lamp row LHL are densely arranged. The eight lamps are arranged so that the intervals gradually increase toward the center, and the center of the substantially square lamp arrangement area LA has the largest interval between the halogen lamps HL and the density of the halogen lamps HL is sparse. Yes. This is because, in general, a temperature drop is likely to occur at the peripheral portion of the semiconductor wafer W during heating by light irradiation, so that the heat treatment apparatus 1 can irradiate a large amount of light to the peripheral portion of the semiconductor wafer W to compensate for this. Is.

  The halogen lamp HL is a filament-type light source that emits light by making the filament incandescent by energizing the filament disposed inside the glass tube. Inside the glass tube, a gas obtained by introducing a trace amount of a halogen element (iodine, bromine, etc.) into an inert gas such as nitrogen or argon is enclosed. By introducing a halogen element, it is possible to set the filament temperature to a high temperature while suppressing breakage of the filament. Therefore, the halogen lamp HL has a characteristic that it has a longer life than a normal incandescent bulb and can continuously radiate strong light. Further, since the halogen lamp HL is a rod-shaped lamp, it has a long life, and by arranging the halogen lamp HL along the horizontal direction, the radiation efficiency to the upper semiconductor wafer W becomes excellent.

  The louver 100 has a thickness of 3 mm, a height of 20 mm, and an outer diameter of approximately 300 mm, which is substantially the same as the semiconductor wafer W to be processed. The louver 100 is formed by entering fine bubbles in transparent quartz glass. It is made of a semi-transparent material so that light is scattered by the bubbles and about 30% of the light is transmitted. As shown in FIG. 8, the louver 100 is attached and supported on the inner wall of the housing 101 by a support 102 formed of transparent quartz glass, and is held by the holding unit 7 above the light source structure LS. More specifically, the semiconductor wafer W is disposed in the halogen heating unit 4 between the light source structure LS and the lower chamber window 64.

  If the mounting position of the louver 100 is too close to the semiconductor wafer W, the influence on the semiconductor wafer W becomes local. In an extreme case, the louver 100 may have a shadow on the semiconductor wafer W, and the illuminance distribution may deteriorate. Conversely, if it is too far from the semiconductor wafer W, the effect of uniforming the illuminance on the semiconductor wafer W is diminished. In the present embodiment, the mounting position of the louver 100 is closer to the halogen lamp HL than the middle between the halogen lamp HL of the upper lamp row UHL of the light source structure LS and the semiconductor wafer W held by the holding unit 7. . Specifically, the distance between the lower end of the louver 100 and the upper end of the halogen lamp HL constituting the upper lamp row UHL is 15 mm, and the distance between the upper end of the louver 100 and the semiconductor wafer W is 70 mm.

  With this arrangement, as shown in FIGS. 8 and 10, the louver 100 is located immediately below the edge of the semiconductor wafer W, and among the halogen lamps HL of the upper lamp row UHL and the lower lamp row LHL, The semiconductor wafers W are positioned in the vicinity of six pieces on both end sides that are densely arranged to compensate for the temperature drop at the peripheral edge of the semiconductor wafer W. Thereby, the louver 100 appropriately scatters the light from the closely arranged halogen lamps HL to reduce the concentration of direct irradiation to the peripheral portion of the semiconductor wafer W, and the peak of the illuminance distribution as will be described later. It is considered that the temperature distribution was made uniform by reducing the variation in the illuminance distribution.

    <5. Control unit 3>

  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. As shown in FIG. 9, the control unit 3 includes a pulse generator 31 and a waveform 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. The waveform setting unit 32 sets the waveform of the pulse signal based on the input content from the input unit 33, and the pulse generator 31 generates the pulse signal according to the waveform. The control unit 3, the trigger circuit 97, and the switching element 96 constitute light emission control means for controlling light emission of the flash lamp FL. The control unit 3 also controls light emission of the halogen lamp HL.

  In addition to the above configuration, the heat treatment apparatus 1 prevents an excessive temperature rise in the halogen heating unit 4, the flash heating unit 5, and the chamber 6 due to thermal energy generated from the halogen lamp HL and the flash lamp FL during the heat treatment of the semiconductor wafer W. Therefore, various cooling structures are provided. For example, the wall of the chamber 6 is provided with a water-cooled tube (not shown). The halogen heating unit 4 and the flash heating unit 5 have an air cooling structure (not shown) that exhausts heat by forming a gas flow therein. The louver 100 has a flat, bottomless cylindrical shape so as not to obstruct the gas flow in the halogen heating unit 4, and has an opening 103 at the center of the support 102 and four openings 104 at the inner side of the louver 100. In addition, the support body 102 has a shape in which portions corresponding to the four corners of the halogen heating unit 4 are cut out. Air is also supplied to the gap between the upper chamber window 63 and the lamp light emission window 53 to cool the flash heating unit 5 and the upper chamber window 63.

    <6. Operation of heat treatment apparatus 1 and effect of louver 100>

  Next, a processing procedure for the semiconductor wafer W in the heat treatment apparatus 1 will be described. Here, the semiconductor wafer W to be processed is a semiconductor substrate to which impurities (ions) are added by an ion implantation method. FIG. 12 is a diagram showing the structure of elements formed on the semiconductor wafer W to be processed in the heat treatment apparatus 1. A source / drain region 112 and an extension region 113 are formed in the silicon substrate 111, and a gate electrode 115 is provided on the upper surface thereof. The extension region 113 is an electrical connection between the source / drain region 112 and the channel. The metal gate electrode 115 is provided on the silicon substrate 111 via the gate insulating film 114, and a ceramic side wall 116 is formed for the measurement. Impurities are introduced into the source / drain regions 112 and the extension regions 113 by an ion implantation method, and the activation of the impurities is performed by 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 air supply valve 84 is opened, and the exhaust valves 89 and 192 are opened to start supply and exhaust of air into the chamber 6. When the valve 84 is opened, nitrogen gas is supplied from the gas supply hole 81 to the heat treatment space 65. When the valve 89 is opened, the gas in the chamber 6 is exhausted from the gas exhaust hole 86. Thereby, the nitrogen gas supplied from the upper part of the heat treatment space 65 in the chamber 6 flows downward and is exhausted from the lower part of the heat treatment space 65.

  Further, when the valve 192 is opened, the gas in the chamber 6 is also exhausted from the transfer opening 66. Further, the atmosphere around the drive unit of the transfer mechanism 10 is also exhausted by an exhaust mechanism (not shown). Note that nitrogen gas is continuously supplied to the heat treatment space 65 during the heat treatment of the semiconductor wafer W in the heat treatment apparatus 1, and the supply amount is appropriately changed according to the treatment process.

  Subsequently, the gate valve 185 is opened to open the transfer opening 66, and the semiconductor wafer W after ion implantation is transferred into the heat treatment space 65 in the chamber 6 through the transfer opening 66 by a transfer robot outside the apparatus. The semiconductor wafer W loaded by the transfer robot advances to a position directly above the holding unit 7 and stops. Then, when the pair of transfer arms 11 of the transfer mechanism 10 moves horizontally from the retracted position to the transfer operation position and rises, the lift pins 12 pass through the through holes 79 and protrude from the upper surface of the holding plate 74 so that the semiconductor wafer. W is received.

  After the semiconductor wafer W is placed on the lift pins 12, the transfer robot leaves the heat treatment space 65 and the transfer opening 66 is closed by the gate valve 185. When the pair of transfer arms 11 are lowered, the semiconductor wafer W is transferred from the transfer mechanism 10 to the holding plate 74 of the holding unit 7 and held in a horizontal posture. As shown in FIG. 8, the semiconductor wafer W is supported by six bumps 75 by point contact, and is held from the upper surface of the holding plate 74 at an interval of 0.5 mm to 3 mm (1 mm in this embodiment). . As a result, a gas layer having a thickness of 1 mm is sandwiched between the lower surface of the semiconductor wafer W and the upper surface of the holding plate 74. The pair of transfer arms 11 lowered to below the holding plate 74 is retracted to the retracted position, that is, inside the recess 62 by the horizontal moving mechanism 13.

After the semiconductor wafer W is placed and held on the holding plate 74 of the holding unit 7, the 40 halogen lamps HL of the halogen heating unit 4 are turned on all at once. The halogen light emitted from the halogen lamp HL is irradiated from the back surface of the semiconductor wafer W through the lower chamber window 64 and the holding plate 74 made of quartz. The temperature of the semiconductor wafer W rises by receiving light irradiation from the halogen lamp HL. In addition, since the transfer arm 11 of the transfer mechanism 10 is retracted to the inside of the recess 62, there is no obstacle to heating by the halogen lamp HL.

  FIG. 11 is a diagram showing a simulation result of the illuminance distribution of the semiconductor wafer W during heating by the halogen lamp HL. In the comparative example in which the louver 100 is not installed, the peak of illuminance is high at a position about 5 cm on the inner side from both edges of the semiconductor wafer W, and the peripheral portion of the semiconductor wafer W is heated more than necessary, resulting in uneven temperature distribution. It is thought that had occurred. On the other hand, in the present invention in which the louver 100 is installed, the peak portion peak generated at the position of about 5 cm on the inner side from both ends of the semiconductor wafer W is lower and substantially flat compared to the comparative example. In addition, although a decrease in illuminance is observed at the central portion of the semiconductor wafer W, it is very slight. In general, as a whole, the peak of illuminance is low, the difference between the maximum and minimum illuminance is small, and the decrease in illuminance at the center is negligible. This is because light from the closely arranged halogen lamps HL is moderately scattered by the louver 100 arranged in front of the halogen lamps HL to reduce the concentration of direct irradiation on the peripheral edge of the semiconductor wafer W, It is considered that the louver 100 has a bottomless shape, and light irradiated on the central portion of the semiconductor wafer W is hardly scattered. In FIG. 11, each graph has fine irregularities because of the random number calculation of the Monte Carlo method used in the simulation, which is different from the actual illuminance.

  Note that, instead of the louver 100, it is conceivable to use a semi-transparent glass donut-shaped disk, but in that case, the illuminance on the front surface of the semiconductor wafer W is lowered at a position far from the semiconductor wafer W, and efficiency is increased. In addition, a shadow of a donut-shaped disk is formed on the surface of the semiconductor wafer W at a position close to the semiconductor wafer W, and the uniformity is deteriorated. Since the bottomless cylindrical louver 100 of the present invention is thin in the surface direction of the semiconductor wafer W, it is difficult to shadow the surface of the semiconductor wafer W, and since it is bottomless, the central portion completely transmits light. Since the decrease in illuminance at the center of the semiconductor wafer W is slight, the efficiency is only slightly degraded. Regarding the shape of the louver capable of obtaining such an effect, according to the experiments by the inventors, good results were obtained at a height of 10 mm to 30 mm for a semiconductor wafer W having a diameter of 300 mm. This corresponds to 1/30 to 1/10 of the diameter of the semiconductor wafer W. Moreover, thickness should just be 5 mm or less. Moreover, although the diameter was 300 mm which is substantially the same as that of the semiconductor wafer W in the above embodiment, the effect is seen in the range of 250 mm to 330 mm.

  The temperature of the semiconductor wafer W heated by the halogen lamp HL is measured by a contact thermometer 130 and a radiation thermometer 120. The temperature of the semiconductor wafer W measured by these is transmitted to the control unit 3. In the present embodiment, the semiconductor wafer W is once heated to a preheating temperature of 650 ° C. or lower (500 ° C. in the present embodiment) by light irradiation from the halogen lamp HL and held. Then, flash heating is executed by irradiating the semiconductor wafer W maintained at the preheating temperature with flash light from the flash lamp FL. In flash heating, the semiconductor wafer W heated to the preheating temperature (500 ° C.) by the halogen lamp HL is irradiated with flash light from the flash lamp FL, so that the surface temperature of the semiconductor wafer W reaches 1000 ° C. or more. (1100 ° C. in this embodiment). By such flash heating, an impurity (ion) activation process of the semiconductor wafer after ion implantation is performed.

  After the flash heating is completed, the halogen lamp HL is turned off when a time has passed so that the surface temperature of the semiconductor wafer W falls to near the preheating temperature. Thereby, the semiconductor wafer W starts to fall from the preheating temperature. Even if the halogen lamp HL is turned off, the temperature of the filament and the tube wall does not immediately decrease, but radiation heat continues to be radiated from the filament and tube wall that are hot for a while, which hinders the temperature of the semiconductor wafer W from falling. Sometimes. In that case, if the halogen lamp HL is extinguished and a shutter mechanism (not shown) is inserted at a light shielding position between the halogen heating unit 4 and the chamber 6 to cut off the radiant heat, the semiconductor wafer can be obtained. The temperature drop rate of W can be increased.

  Then, after the temperature of the semiconductor wafer W is lowered to a predetermined temperature or lower, the pair of transfer arms 11 of the transfer mechanism 10 moves horizontally from the retracted position to the transfer operation position again and rises, whereby the lift pins 12 are held. The semiconductor wafer W protruding from the upper surface of the plate 74 and receiving the heat treatment is received from the holding plate 74. Subsequently, the transfer opening 66 closed by the gate valve 185 is opened, and the semiconductor wafer W placed on the lift pins 12 is unloaded by the transfer robot outside the apparatus, and the heat treatment of the semiconductor wafer W in the heat treatment apparatus 1 is performed. Is completed.

  In the present embodiment, the semiconductor wafer W heated to a preheating temperature of 650 ° C. or less by light irradiation from the halogen lamp HL is irradiated with flash light from the flash lamp FL, so that the surface arrival temperature of the semiconductor wafer W is 1000 ° C. or more. By performing the flash heating, it is possible to promote the recovery of defects introduced at the time of impurity implantation while suppressing the diffusion of the implanted impurity and to activate the impurity satisfactorily.

    <7. Modification>

  In the above embodiment, the halogen lamps HL constituting the upper lamp row UHL and the halogen lamps HL constituting the lower lamp row LHL are arranged in a direction orthogonal to each other to prevent or reduce unevenness in illuminance due to the lamp arrangement. However, other arrangements, for example, in only one direction may be used.

  Further, in the above embodiment, each of the upper lamp row UHL and the lower lamp row LHL is densely arranged with 6 pieces at both ends, and the 8 pieces at the central portion are gradually spaced toward the central portion. The center of the substantially square lamp arrangement area LA is the largest in the interval between the halogen lamps HL and the density of the halogen lamp HL is sparse. The peripheral portion is configured to increase the amount of emitted light per unit area. However, the present invention is not limited to this. For example, even if the halogen lamps are arranged at equal intervals, the halogen located at the center of the light emitting region surface is arranged. The rated capacity of the peripheral halogen lamp is larger than that of the halogen lamp located at the center of the light emitting area surface, such as 50 W for the lamp and 100 W for the peripheral halogen lamp. It may be used as such.

Further, the louver 100 is not limited to the above-described one in which fine bubbles are formed in transparent quartz glass, but may be a semi-transparent material from the beginning, or a material made transparent by roughening the surface of the transparent material. Good. The louver 100 may be attached at a position closer to the halogen lamp HL than just between the halogen lamp HL of the upper lamp row UHL of the light source structure LS and the semiconductor wafer W held by the holding unit 7.

DESCRIPTION OF SYMBOLS 1 Heat processing apparatus 4 Halogen heating part 5 Flash heating part 6 Chamber 7 Holding part 100 Louver 102 Support body W Semiconductor wafer HL Halogen lamp FL Flash lamp LS Light source structure LA lamp arrangement area

Claims (6)

A heat treatment apparatus for heating a substrate by irradiating the substrate with light,
A support means for supporting the substrate;
A light source structure that has a light emitting area surface that is larger than the substrate, and that performs light irradiation with the light emitting area surface facing a substrate supported by the support means;
A translucent light-scattering member having a cylindrical shape and disposed between the substrate supported by the support means and the light source structure and configured to transmit a part of incident light and scatter a part thereof; ,
Equipped with a,
The light source structure is configured by arranging a plurality of halogen lamps so that the light emission amount per unit area is larger in the peripheral portion than in the central portion of the light emitting region surface,
The said light-scattering member scatters the light from the said peripheral part of the said light source structure, The heat processing apparatus characterized by the above-mentioned . The heat treatment apparatus according to claim 1,
The heat treatment apparatus , wherein the light scattering member is arranged at a position closer to the light source structure than an intermediate between the light source structure and the substrate supported by the support means . In the heat treatment apparatus according to claim 1 or 2,
The heat treatment apparatus according to claim 1, wherein the substrate is a semiconductor wafer, and the light scattering member has a bottomless cylindrical shape disposed coaxially with the semiconductor wafer. In the heat treatment apparatus according to claim 3,
The heat treatment apparatus characterized in that the cylindrical shape of the light scattering member is substantially the same diameter as the diameter of the semiconductor wafer. The heat treatment apparatus according to any one of claims 1 to 4,
The heat treatment apparatus, wherein the light scattering member is made of a glass material having a light scattering fine structure. In the heat treatment apparatus according to any one of claims 1 to 5,
A heat treatment apparatus, wherein the light source structure includes a light source group including a plurality of rod-shaped halogen lamps arranged in parallel.

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