JP6138610B2 - 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 by irradiating light.

  In the semiconductor device manufacturing process, impurity introduction is an indispensable step for forming a pn junction in a semiconductor wafer. Currently, impurities are generally introduced by ion implantation and subsequent annealing. The ion implantation method is a technique in which impurity elements such as boron (B), arsenic (As), and phosphorus (P) are ionized and collided with a semiconductor wafer at a high acceleration voltage to physically perform impurity implantation. The implanted impurities are activated by annealing. At this time, if the annealing time is about several seconds or more, the implanted impurities are deeply diffused by heat, and as a result, the junction depth becomes deeper than required, and there is a possibility that good device formation may be hindered.

  Therefore, in recent years, flash lamp annealing (FLA) has attracted attention as an annealing technique for heating a semiconductor wafer in an extremely short time. Flash lamp annealing is a semiconductor wafer in which impurities are implanted by irradiating the surface of the semiconductor wafer with flash light using a xenon flash lamp (hereinafter, simply referred to as “flash lamp” means xenon flash lamp). Is a heat treatment technique for raising the temperature of only the surface of the material in a very short time (several milliseconds or less).

  The radiation spectral distribution of a xenon flash lamp ranges from the ultraviolet region to the near infrared region, has a shorter wavelength than 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. For this reason, if the temperature is raised for a very short time by the xenon flash lamp, only the impurity activation can be performed without deeply diffusing the impurities.

  As a heat treatment apparatus using such a xenon flash lamp, Patent Document 1 discloses that a plurality of bumps (support pins) are formed on the upper surface of a susceptor made of quartz, and flash heating is performed on a semiconductor wafer supported by the bumps by point contact. Techniques for performing are disclosed. In the apparatus disclosed in Patent Document 1, a halogen lamp irradiates light from the lower surface of a semiconductor wafer placed on a susceptor and preheats, and then flash heat is applied to the wafer surface by irradiating flash light from a flash lamp.

JP 2009-164451 A

  However, as disclosed in Patent Document 1, when a semiconductor wafer is supported by point contact with a plurality of bumps, heat conduction occurs between the semiconductor wafer and the bumps at the contact points. When preheating is performed by irradiating light from a halogen lamp, quartz hardly absorbs light, so that the temperature of the semiconductor wafer becomes higher than that of the quartz susceptor, and heat is transferred from the semiconductor wafer to the bumps. As a result, there is a problem that the temperature is relatively lowered in the vicinity of the contact point with the plurality of bumps in the surface of the semiconductor wafer as compared with other regions. If the in-plane temperature distribution of the semiconductor wafer becomes non-uniform at the stage of preheating with a halogen lamp, there is a problem that the maximum temperature is also non-uniform during the subsequent flash light irradiation without being eliminated. .

  This invention is made | formed in view of the said subject, and it aims at providing the heat processing apparatus which can make uniform temperature distribution in the substrate surface at the time of light irradiation.

In order to solve the above-mentioned problems, the invention of claim 1 is a heat treatment apparatus for heating a substrate by irradiating the substrate with light, wherein a chamber for accommodating the substrate and a plurality of support pins are erected on the first surface. A quartz plate-shaped susceptor that supports the substrate with the plurality of support pins in the chamber; a light irradiation unit that irradiates light through the susceptor through the substrate supported by the susceptor; and and an auxiliary radiation portion provided on the side, a reflective portion for reflecting the light emitted from the auxiliary radiation portion toward the support pin on the second surface of the susceptor, said reflecting portion, wherein It is a recessed part formed in the 2nd surface of a susceptor, The said reflection part has the same shape as each of these support pins, It is characterized by the above-mentioned.

According to a second aspect of the present invention, in a heat treatment apparatus for heating a substrate by irradiating the substrate with light, a chamber for accommodating the substrate and a plurality of support pins are provided upright on the first surface, A quartz flat plate-shaped susceptor that supports the substrate with the plurality of support pins, a light irradiation unit that irradiates light through the susceptor through the substrate supported by the susceptor, and a side of the susceptor. An auxiliary irradiating part, and a reflecting part for reflecting the light emitted from the auxiliary irradiating part toward the support pin is provided on the second surface of the susceptor, and the reflecting part is provided on the second surface of the susceptor. the Katachi設been recesses der is, the reflecting portion may have a plurality of respective central axes is line symmetrical about the shape of the support pin.

According to a third aspect of the present invention, in the heat treatment apparatus according to the second aspect of the invention, the reflecting portion has a conical reflecting surface.

According to a fourth aspect of the present invention, in the heat treatment apparatus according to the second aspect of the invention, the reflecting portion has a convex reflecting surface.

According to a fifth aspect of the present invention, in the heat treatment apparatus according to the second aspect of the invention, the reflecting portion has a concave reflecting surface.

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 auxiliary irradiation section includes a laser light source that emits a laser beam.

According to a seventh aspect of the invention, in the heat treatment apparatus according to the sixth aspect of the invention, the laser light source emits a laser beam parallel to the first surface and the second surface of the susceptor.

According to an eighth aspect of the present invention, in the heat treatment apparatus according to any one of the first to fifth aspects, the auxiliary irradiation section includes a halogen lamp.

According to a ninth aspect of the present invention, in the heat treatment apparatus according to the eighth aspect of the present invention, the halogen lamp is provided in an annular shape so as to surround the periphery of the susceptor.

  According to the present invention, since the reflection part that reflects the light emitted from the auxiliary irradiation part toward the support pin is provided on the second surface of the susceptor, the support pin and the substrate that are likely to be lowered in temperature when light is emitted from the light irradiation part. The vicinity of the contact point can be supplementarily heated to suppress a temperature drop, and the temperature distribution in the substrate surface can be made uniform.

In particular, according to the invention of claim 1 , since the reflecting portion has the same shape as each of the plurality of support pins, the thickness is constant over the entire surface of the susceptor, the heat capacity in the thickness direction becomes uniform, and light irradiation is performed. The temperature distribution in the substrate surface can be made more uniform.

In particular, according to the second aspect of the present invention, since the reflecting portion has a shape that is line symmetric about the central axis of each of the plurality of support pins, the light emitted from the auxiliary irradiating portion can be any of the surroundings of the reflecting portion. Even if the light is incident from the direction, the light can be guided toward the support pin.

In particular, according to the invention of claim 4 , since the reflecting portion has a convex reflecting surface, the light emitted from the auxiliary irradiating portion can be guided to the support pin so as to be reflected and spread. A wide range in the vicinity of the contact point can be heated.

In particular, according to the invention of claim 5 , since the reflecting portion has a concave reflecting surface, the light emitted from the auxiliary irradiating portion can be guided to the support pin so as to be reflected and converged. It is possible to intensively heat a narrow range in the vicinity of the contact point.

In particular, according to the seventh aspect of the present invention, since the laser light source emits laser light in parallel with the first and second surfaces of the susceptor, the laser light travels in parallel with the susceptor even if the position of the susceptor is slightly shifted. As a result, it is possible to prevent an unnecessary portion of the substrate from being irradiated and heated.

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 which shows the whole external appearance of a holding | maintenance part. It is the top view which looked at the holding | maintenance part from the upper surface. It is a figure which shows the peripheral part vicinity of the susceptor holding the semiconductor wafer. It is the figure which looked at the reflection part from the bottom face side of a susceptor. 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 figure which shows the optical path of the laser beam radiate | emitted from the laser light source of 1st Embodiment. It is a figure which shows the reflection part of 2nd Embodiment. It is a figure which shows the reflection part of 3rd Embodiment. It is a figure which shows the reflection part of 4th Embodiment. It is a figure which shows the reflection part of 5th Embodiment. It is a figure which shows the reflection part of 6th Embodiment. It is a figure which shows the reflection part and support pin of 7th Embodiment. It is a figure which shows the example which provided the halogen lamp as an auxiliary | assistant irradiation part.

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

<First Embodiment>
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 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 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. The heat treatment apparatus 1 includes a holding unit 7 that holds the semiconductor wafer W in a horizontal posture inside the chamber 6, and a transfer mechanism 10 that transfers the semiconductor wafer W between the holding unit 7 and the outside of the apparatus, Is provided. Furthermore, 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 the flash 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 can be opened and closed by a gate valve 185. The transport opening 66 is connected to the outer peripheral surface of the recess 62. Therefore, when the gate valve 185 opens the transfer opening 66, the semiconductor wafer W is carried into the heat treatment space 65 through the recess 62 from the transfer opening 66 and the semiconductor wafer W is carried out 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 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 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. Note that the processing gas is not limited to nitrogen gas, but is an inert gas such as argon (Ar) or helium (He), or oxygen (O ₂ ), hydrogen (H ₂ ), chlorine (Cl ₂ ), A reactive gas such as hydrogen chloride (HCl), ozone (O ₃ ), or ammonia (NH ₃ ) may be used.

  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 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 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 chamber 6 is exhausted through the transfer opening 66.

  FIG. 2 is a perspective view showing the overall appearance of the holding unit 7. FIG. 3 is a plan view of the holding unit 7 as viewed from above. The holding part 7 includes a base ring 71, a connecting part 72, and a susceptor 74. The base ring 71, the connecting portion 72, and the susceptor 74 are all made of quartz. That is, the whole holding part 7 is made of quartz.

  The base ring 71 is an annular quartz member. The base ring 71 is supported on the wall surface of the chamber 6 by being placed on the bottom surface of the recess 62 (see FIG. 1). On the upper surface of the base ring 71 having an annular shape, a plurality of connecting portions 72 (four in this embodiment) are erected along the circumferential direction. The connecting portion 72 is also a quartz member, and is fixed to the base ring 71 by welding. The shape of the base ring 71 may be an arc shape in which a part is omitted from the annular shape.

  The flat susceptor 74 is supported by four connecting portions 72 provided on the base ring 71. The susceptor 74 is a circular holding plate made of quartz, and places and holds the semiconductor wafer W to be processed. The diameter of the susceptor 74 is larger than the diameter of the semiconductor wafer W. That is, the susceptor 74 has a larger planar size than the semiconductor wafer W. Further, the thickness of the susceptor 74 can be set as appropriate, and is, for example, 2.5 mm.

  A plurality of support pins 75 are erected on the upper surface (first surface) of the susceptor 74. In the present embodiment, a total of six support pins 75 are erected along the circumference of a circular susceptor 74 that is concentric with the outer circumference circle every 60 °. The diameter of the circle in which the six support pins 75 are arranged (the distance between the support pins 75 facing each other) is smaller than the diameter of the semiconductor wafer W. Each support pin 75 is made of quartz. The plurality of support pins 75 may be erected by being fitted into a recess formed in the upper surface of the susceptor 74, for example.

  A plurality (five in this embodiment) of guide pins 76 are erected on the upper surface of the susceptor 74. Five guide pins 76 are also provided along a circumference that is concentric with the outer circumference of the susceptor 74. However, 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 also formed of quartz. Further, the susceptor 74 is provided with four through holes 79 through which lift pins 12 of the transfer mechanism 10 to be described later penetrate for the delivery of the semiconductor wafer W.

  Four connecting portions 72 erected on the base ring 71 and the lower peripheral edge portion of the susceptor 74 are fixed by welding. That is, the susceptor 74 and the base ring 71 are fixedly connected by the connecting portion 72. When the base ring 71 of the holding unit 7 is supported on the wall surface of the chamber 6, the holding unit 7 is attached to the chamber 6. In a state where the holding unit 7 is mounted on the chamber 6, the susceptor 74 is in a horizontal posture (a posture in which the normal line matches the vertical direction).

  The semiconductor wafer W carried into the chamber 6 is placed and supported in a horizontal posture on the susceptor 74 of the holding unit 7 attached to the chamber 6. The semiconductor wafer W is supported by the susceptor 74 in a point contact by six support pins 75 provided upright on the upper surface of the susceptor 74. That is, the semiconductor wafer W is supported by the six support pins 75 at a predetermined interval from the upper surface of the susceptor 74. Further, the height of the guide pin 76 is higher than the height of the support pin 75. Accordingly, the horizontal displacement of the semiconductor wafer W supported by the six support pins 75 is prevented by the guide pins 76.

  FIG. 4 is a view showing the vicinity of the periphery of the susceptor 74 holding the semiconductor wafer W. As shown in FIG. As shown in the figure, a reflecting portion 77 is provided on the bottom surface (second surface) of the susceptor 74. FIG. 5 is a view of the reflecting portion 77 as viewed from the bottom surface side of the susceptor 74. The reflective portion 77 of the first embodiment is a concave portion formed on the bottom surface of the susceptor 74. As shown in FIG. 4, the cross-sectional shape of the recess (cross section cut along the radial direction of the susceptor 74) is a right triangle. The reflection part 77 having such a shape is provided corresponding to each of the six support pins 75. That is, in the first embodiment, six reflecting portions 77 are provided corresponding to the six support pins 75. As shown in FIG. 5, a reflecting portion 77 is formed on the opposite side of the position of the support pin 75 erected on the upper surface of the susceptor 74.

  Further, as shown in FIGS. 3 to 5, a laser light source 21 is installed on the side of the susceptor 74. In the first embodiment, six laser light sources 21 are provided so as to face the six support pins 75 and the six reflecting portions 77. The six laser light sources 21 may be installed in the recess 62 of the chamber 6.

  The laser light source 21 emits laser light in a wavelength region (4 μm or less) that is transmitted by quartz constituting the susceptor 74 and a wavelength region (1.1 μm or less) that is absorbed by the silicon semiconductor wafer W. That is, the laser light source 21 emits laser light having a wavelength of 1.1 μm or less. Further, the laser light source 21 emits laser light toward the corresponding reflecting portion 77 in parallel with the main surface (upper surface and bottom surface) of the susceptor 74. The laser light emitted from the laser light source 21 is reflected by the reflecting portion 77 and travels toward the support pin 75. This operation will be further described later.

  FIG. 6 is a plan view of the transfer mechanism 10. FIG. 7 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 (solid line position in FIG. 6) 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 retreat positions (two-dot chain line positions in FIG. 6) 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 through holes 79 (see FIGS. 2 and 3) formed in the susceptor 74, and the lift pins The upper end of 12 protrudes from the upper surface of the susceptor 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 base ring 71 of the holding unit 7. Since the base ring 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 a 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 provided. Is discharged to the outside of the chamber 6.

  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 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 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 previously stored in the capacitor is converted into an extremely short light pulse of 0.1 to 100 milliseconds, so that the continuous lighting such as the halogen lamp HL is possible. It has the characteristic that it can irradiate extremely strong light compared with a light source. 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 the flash light emitted from the plurality of flash lamps FL toward the heat treatment space 65. The reflector 52 is formed of an aluminum alloy plate, and the surface (the surface facing the flash lamp FL) is roughened by blasting.

  A plurality of halogen lamps HL (40 in this embodiment) are built in the halogen heating unit 4 provided below the chamber 6. The plurality of halogen lamps HL irradiate the heat treatment space 65 from below the chamber 6 through the lower chamber window 64. FIG. 8 is a plan view showing the arrangement of a plurality of halogen lamps HL. In the present embodiment, 20 halogen lamps HL are arranged in two upper and lower stages. Each halogen lamp HL is a rod-shaped lamp having a long cylindrical shape. The 20 halogen lamps HL in both the upper and lower stages are arranged so that their longitudinal directions are parallel to each other along the main surface of the semiconductor wafer W held by the holding unit 7 (that is, along the horizontal direction). Yes. Therefore, the plane formed by the arrangement of the halogen lamps HL in both the upper stage and the lower stage is a horizontal plane.

  Further, as shown in FIG. 8, the arrangement density of the halogen lamps HL in the region facing the peripheral portion is higher than the region facing the central portion of the semiconductor wafer W held by the holding portion 7 in both the upper and lower steps. Yes. That is, in both the upper and lower stages, the arrangement pitch of the halogen lamps HL is shorter in the peripheral part than in the central part of the lamp array. For this reason, it is possible to irradiate a larger amount of light to the peripheral portion of the semiconductor wafer W where the temperature is likely to decrease during heating by light irradiation from the halogen heating unit 4.

  Further, the lamp group composed of the upper halogen lamp HL and the lamp group composed of the lower halogen lamp HL are arranged so as to intersect in a lattice pattern. That is, a total of 40 halogen lamps HL are arranged so that the longitudinal direction of the upper halogen lamps HL and the longitudinal direction of the lower halogen lamps HL are orthogonal to each other.

  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. That is, the halogen lamp HL is a continuous lighting lamp that emits light continuously for at least one second. 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.

  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 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). Further, the halogen heating unit 4 and the flash heating unit 5 have an air cooling structure in which a gas flow is formed inside to exhaust heat. Air is also supplied to the gap between the upper chamber window 63 and the lamp light emission window 53 to cool the flash heating unit 5 and the upper chamber window 63. Further, the heat treatment apparatus 1 is provided with a temperature sensor (a radiation thermometer and / or a contact-type temperature watch) that measures the temperature of the semiconductor wafer W held on the susceptor 74.

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

  First, the 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 carried in by the carrying 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 protrude from the upper surface of the susceptor 74 through the through holes 79 and the semiconductor wafer W. Receive. At this time, the lift pin 12 rises above the upper end of the support pin 75 of the susceptor 74.

  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 susceptor 74 of the holding unit 7 and held from below in a horizontal posture.

  The semiconductor wafer W is supported by the susceptor 74 in a point contact by six support pins 75 provided upright on the upper surface of the susceptor 74. The semiconductor wafer W is supported by six support pins 75 so that the center thereof coincides with the central axis of the susceptor 74 (that is, at the center of the upper surface of the susceptor 74). The periphery of the semiconductor wafer W supported by the support pins 75 is surrounded by five guide pins 76. The semiconductor wafer W is held by the susceptor 74 with the surface on which the pattern is formed and the impurities are implanted as the upper surface. A predetermined gap is formed between the back surface (main surface opposite to the front surface) of the semiconductor wafer W supported by the plurality of support pins 75 and the top surface of the susceptor 74, and the semiconductor wafer W is connected to the top surface of the susceptor 74. Supported in parallel. The pair of transfer arms 11 lowered to below the susceptor 74 is retracted to the retracted position, that is, inside the recess 62 by the horizontal movement mechanism 13.

  After the semiconductor wafer W is supported from below in a horizontal posture by the susceptor 74 of the holding unit 7, the 40 halogen lamps HL of the halogen heating unit 4 are turned on all at once and preheating (assist heating) is started. The halogen light emitted from the halogen lamp HL passes through the lower chamber window 64 and the susceptor 74 made of quartz and is irradiated from the back surface of the semiconductor wafer W. By receiving light from the halogen lamp HL, the semiconductor wafer W is preheated and the temperature rises. 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.

  When preheating with the halogen lamp HL is performed, the temperature of the semiconductor wafer W is measured by a temperature sensor (not shown). The measured temperature of the semiconductor wafer W is transmitted from the temperature sensor to the control unit 3. The controller 3 monitors whether or not the temperature of the semiconductor wafer W that is heated by light irradiation from the halogen lamp HL has reached a predetermined preheating temperature T1. The preheating temperature T1 is set to about 200 ° C. to 800 ° C., preferably about 350 ° C. to 600 ° C. (in this embodiment, 600 ° C.) at which impurities added to the semiconductor wafer W are not likely to diffuse due to heat. .

  After the temperature of the semiconductor wafer W reaches the preheating temperature T1, the control unit 3 maintains the semiconductor wafer W at the preheating temperature T1 for a while. Specifically, when the temperature of the semiconductor wafer W measured by the temperature sensor reaches the preheating temperature T1, the control unit 3 controls the output of the halogen lamp HL so that the temperature of the semiconductor wafer W is substantially equal to the preheating temperature. T1 is maintained for a predetermined time.

  By the way, as described above, the preliminary heating by the halogen lamp HL is performed in a state where the semiconductor wafer W is supported by point contact with the six support pins 75. The quartz susceptor 74 including the support pins 75 transmits the light emitted from the halogen lamp HL with little absorption. For this reason, at the time of preheating, the semiconductor wafer W absorbs light from the halogen lamp HL and rises in temperature, while the susceptor 74 including the support pins 75 does not rise so much and is relatively lower in temperature than the semiconductor wafer W. Become. Therefore, heat conduction from the semiconductor wafer W to the support pins 75 that are in direct contact occurs, and the wafer temperature in the vicinity of the contact point by the six support pins 75 is relatively lowered as compared with other regions. As a result, the in-plane temperature distribution of the semiconductor wafer W tends to be non-uniform.

  For this reason, in the first embodiment, the laser light source 21 as an auxiliary irradiation unit is provided on the side of the susceptor 74, and the reflection unit 77 is provided on the bottom surface of the susceptor 74. FIG. 9 is a diagram illustrating an optical path of laser light emitted from the laser light source 21 of the first embodiment. In the present embodiment, six reflecting portions 77 are provided on the bottom surface of the susceptor 74 corresponding to the six support pins 75. Then, six laser light sources 21 are provided so as to face the six reflecting portions 77. Each laser light source 21 emits laser light in parallel to the upper surface and the bottom surface of the susceptor 74 toward the corresponding reflecting portion 77. The wavelength of the laser light emitted from the laser light source 21 is 1.1 μm or less, which is the absorption wavelength region of silicon, and the diameter of the light beam is smaller than the thickness of the susceptor 74.

  The laser light emitted from the laser light source 21 enters from the end surface of the susceptor 74, travels in the susceptor 74 in parallel with the top surface and the bottom surface, and reaches the reflecting surface 77 a of the reflecting portion 77. At this time, since the laser light is incident on the reflecting surface 77a at an incident angle larger than the critical angle from quartz to air (about 43 ° to 44 °), it is totally reflected by the reflecting surface 77a. Then, the laser beam totally reflected by the reflecting surface 77a goes to the support pins 75 and reaches the vicinity of the contact point with the support pins 75 of the semiconductor wafer W. In other words, the reflecting surface 77a of the reflecting portion 77 has an incident angle of light that travels parallel to the upper surface and the bottom surface of the susceptor 74 and becomes larger than the critical angle, and the light is reflected to support the support pin 75. It is formed at a position and an angle (angle formed with a horizontal plane) so as to go to.

  The wavelength of the laser light emitted from the laser light source 21 is 1.1 μm or less absorbed by the silicon semiconductor wafer W. Accordingly, the temperature of the semiconductor wafer W is increased by absorbing the laser light in the vicinity of the contact point with the support pins 75. As a result, the vicinity of the contact point with the support pin 75 of the semiconductor wafer W, which is likely to cause a relative temperature drop during preheating, is supplementarily heated to suppress the temperature drop, and the temperature difference between the contact point vicinity and the peripheral region. Can be minimized.

  Such auxiliary heating in the vicinity of the contact point with the support pin 75 by laser light irradiation is performed for each of the six support pins 75. As a result, the vicinity of the contact portion between the six support pins 75 and the semiconductor wafer W is individually heated to raise the temperature, thereby preventing the temperature drop and making the in-plane temperature distribution of the semiconductor wafer W uniform. it can.

  The flash lamp FL of the flash heating unit 5 irradiates the surface of the semiconductor wafer W with flash light when a predetermined time elapses after the temperature of the semiconductor wafer W reaches the preheating temperature T1 by light irradiation from the halogen lamp HL. . At this time, a part of the flash light emitted from the flash lamp FL goes directly into 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.

  Since the flash heating is performed by irradiation with flash light (flash light) 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 is converted into a light pulse in which the electrostatic energy stored in the capacitor in advance is extremely short, and the irradiation time is extremely short, about 0.1 milliseconds to 100 milliseconds. It is a strong flash. Then, the surface temperature of the semiconductor wafer W that is flash-heated by flash light irradiation from the flash lamp FL instantaneously rises to a processing temperature T2 of 1000 ° C. or more, and the impurities injected into the semiconductor wafer W are activated. Later, the surface temperature drops rapidly. As described above, in the heat treatment apparatus 1, the surface temperature of the semiconductor wafer W can be raised and lowered in a very short time, so that the impurities are activated while suppressing diffusion of 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.

  In the first embodiment, the laser light emitted from the laser light source 21 is totally reflected by the reflecting portion 77 and guided toward the support pin 75, thereby reducing the temperature near the contact portion between the support pin 75 and the semiconductor wafer W. The temperature distribution in the surface of the semiconductor wafer W in the preheating stage is suppressed to be uniform. As a result, the in-plane temperature distribution on the surface of the semiconductor wafer W at the time of flash light irradiation can be made uniform.

  After the end of the flash heat treatment, the halogen lamp HL is turned off after a predetermined time has elapsed. Thereby, the temperature of the semiconductor wafer W is rapidly lowered from the preheating temperature T1. The temperature of the semiconductor wafer W during the temperature drop is also measured by the temperature sensor, and the measurement result is transmitted to the control unit 3. The controller 3 monitors whether or not the temperature of the semiconductor wafer W has dropped to a predetermined temperature from the measurement result. 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 is moved horizontally from the retracted position to the transfer operation position again and lifted, whereby the lift pins 12 are moved to the susceptor. The semiconductor wafer W protruding from the upper surface of 74 and subjected to the heat treatment is received from the susceptor 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 first embodiment, the laser light source 21 is provided on the side of the susceptor 74, and the concave reflecting portion 77 is provided on the bottom surface of the susceptor 74. The laser light emitted from the laser light source 21 is guided to the support pin 75 by total reflection at the reflection portion 77. As a result, the vicinity of the contact point between the support pin 75 and the semiconductor wafer W where the temperature is likely to decrease is supplementarily heated to suppress the temperature decrease, and the in-plane temperature distribution of the semiconductor wafer W during the preheating is made uniform. Can do. As a result, the in-plane temperature distribution on the surface of the semiconductor wafer W during flash heating can be made uniform.

  If the laser light is only irradiated near the contact portion between the support pin 75 and the semiconductor wafer W, the laser light is emitted directly from the laser light source 21 toward the contact portion without providing the reflection portion 77. Is also possible. However, when this is done, laser light is emitted from the laser light source 21 toward the semiconductor wafer W at a predetermined angle. If the position of the susceptor 74 is slightly shifted, the support pins 75 and other than the contact portions are not located. The laser beam reaches the region and is heated, and as a result, the non-uniformity of the temperature distribution may be further increased. In the first embodiment, laser light is emitted from the laser light source 21 in parallel with the upper surface and the bottom surface of the susceptor 74 (that is, parallel to the semiconductor wafer W supported by the susceptor 74), and is reflected by the reflecting portion 77 to support pins 75. To guide you to. For this reason, even if the position of the susceptor 74 is slightly shifted, the laser light travels in a plane parallel to the semiconductor wafer W (in the first embodiment, inside the susceptor 74), and the semiconductor wafer W is unnecessary. It is possible to prevent the heat from reaching the spot.

Second Embodiment
Next, a second embodiment of the present invention will be described. The overall configuration of the heat treatment apparatus of the second embodiment is substantially the same as that of the first embodiment. The processing procedure for the semiconductor wafer W in the heat treatment apparatus of the second embodiment is also the same as that of the first embodiment. The second embodiment differs from the first embodiment in the structure of the reflecting portion formed on the susceptor 74.

  FIG. 10 is a diagram illustrating the reflection unit 177 according to the second embodiment. The reflecting portion 77 of the first embodiment is a concave portion formed on the bottom surface of the susceptor 74, whereas the reflecting portion 177 of the second embodiment is a quartz convex portion protruding from the bottom surface of the susceptor 74. is there. The cross-sectional shape of the convex portion is a right triangle, which is the same as the cross-sectional shape of the reflecting portion 77 of the first embodiment. The reflection part 177 having such a shape is provided corresponding to each of the six support pins 75.

  Similarly to the first embodiment, six laser light sources 21 are installed on the side of the susceptor 74 so as to face the six support pins 75 and the six reflecting portions 177. The laser light source 21 emits laser light in a wavelength region (1.1 μm or less) that is transmitted by quartz and absorbed by silicon.

  In the second embodiment, each of the six laser light sources 21 emits laser light in parallel to the upper surface and the bottom surface of the susceptor 74 toward the corresponding reflecting portion 177. The laser light emitted from the laser light source 21 enters the reflecting portion 177 and reaches the reflecting surface 177a. At this time, since the laser light is incident on the reflecting surface 177a at an incident angle larger than the critical angle from quartz to air, it is totally reflected by the reflecting surface 177a. Then, the laser beam totally reflected by the reflecting surface 177a travels toward the support pin 75 and reaches the vicinity of the contact point with the support pin 75 of the semiconductor wafer W. In other words, the reflecting surface 177a of the reflecting portion 177 has an incident angle of incident light that travels parallel to the upper surface and the bottom surface of the susceptor 74 and becomes larger than the critical angle. It is formed at a position and an angle (angle formed with a horizontal plane) so as to go to.

  In the vicinity of the contact point of the semiconductor wafer W with the support pins 75, the laser beam is absorbed and the temperature rises. Such auxiliary heating in the vicinity of the contact point with the support pin 75 by laser light irradiation is performed for each of the six support pins 75. As a result, the vicinity of the contact point between the six support pins 75 and the semiconductor wafer W is individually heated to increase the temperature, and the temperature in the surface of the semiconductor wafer W during the preheating is uniformed by preventing the temperature from decreasing. Can be. As a result, the in-plane temperature distribution on the surface of the semiconductor wafer W during flash heating can be made uniform.

<Third Embodiment>
Next, a third embodiment of the present invention will be described. The overall configuration of the heat treatment apparatus of the third embodiment is substantially the same as that of the first embodiment. The processing procedure for the semiconductor wafer W in the heat treatment apparatus of the third embodiment is also the same as that of the first embodiment. The third embodiment differs from the first embodiment in the structure of the reflecting portion formed on the susceptor 74.

  FIG. 11 is a diagram illustrating the reflection unit 277 of the third embodiment. The reflecting portion 277 of the third embodiment is a quartz convex portion protruding from the bottom surface of the susceptor 74. The reflecting portion 277 has a shape that is line symmetric about the central axis of the support pin 75. Specifically, the reflecting portion 277 of the third embodiment has a conical reflecting surface 277a. Such a line-symmetric reflecting portion 277 is provided corresponding to each of the six support pins 75.

  Similarly to the first embodiment, six laser light sources 21 are installed on the side of the susceptor 74 so as to face the six support pins 75 and the six reflecting portions 277. The laser light source 21 emits laser light in a wavelength region (1.1 μm or less) that is transmitted by quartz and absorbed by silicon.

  In the third embodiment, each of the six laser light sources 21 emits laser light in parallel to the upper surface and the bottom surface of the susceptor 74 toward the corresponding reflecting portion 277. The laser light emitted from the laser light source 21 enters the reflecting portion 277 and reaches the reflecting surface 277a. At this time, since the laser light is incident on the reflecting surface 277a at an incident angle larger than the critical angle from quartz to air, it is totally reflected by the reflecting surface 277a. Then, the laser beam totally reflected by the reflecting surface 277a goes to the support pin 75 and reaches the vicinity of the contact point with the support pin 75 of the semiconductor wafer W.

  In the vicinity of the contact point of the semiconductor wafer W with the support pins 75, the laser beam is absorbed and the temperature rises. Such auxiliary heating in the vicinity of the contact point with the support pin 75 by laser light irradiation is performed for each of the six support pins 75. As a result, the vicinity of the contact point between the six support pins 75 and the semiconductor wafer W is individually heated to increase the temperature, and the temperature in the surface of the semiconductor wafer W during the preheating is uniformed by preventing the temperature from decreasing. Can be. As a result, the in-plane temperature distribution on the surface of the semiconductor wafer W during flash heating can be made uniform.

  Further, in the third embodiment, the reflecting portion 277 has a shape that is line symmetric about the central axis of the support pin 75. Therefore, as indicated by a dotted line in FIG. 11, even if laser light is incident from any direction around the reflecting portion 277 (but parallel to the top and bottom surfaces of the susceptor 74), the laser light is reflected by the reflecting surface 277a. The light is reflected and guided to the support pin 75. For this reason, the freedom degree of the incident direction of the laser beam by the laser light source 21 becomes high, and the installation position of the laser light source 21 can be varied. Further, even if the position of the susceptor 74 or the optical axis of the laser light from the laser light source 21 is shifted and the laser light is incident on the reflection part 277 different from the corresponding one, it is guided to the support pin 75.

<Fourth embodiment>
Next, a fourth embodiment of the present invention will be described. The overall configuration of the heat treatment apparatus of the fourth embodiment is substantially the same as that of the first embodiment. The processing procedure for the semiconductor wafer W in the heat treatment apparatus of the fourth embodiment is also the same as that of the first embodiment. The fourth embodiment differs from the first embodiment in the structure of the reflecting portion formed on the susceptor 74.

  FIG. 12 is a diagram illustrating the reflecting portion 377 of the fourth embodiment. The reflecting portion 377 of the fourth embodiment is a quartz convex portion protruding from the bottom surface of the susceptor 74. The reflecting portion 377 has a shape that is line symmetric about the central axis of the support pin 75. Specifically, the reflecting portion 377 of the fourth embodiment has a convex reflecting surface 377a. Here, the convex shape is a shape of a curved surface that is convex toward the support pin 75 side. Such a line-symmetric reflecting portion 377 is provided corresponding to each of the six support pins 75.

  Similarly to the first embodiment, six laser light sources 21 are installed on the side of the susceptor 74 so as to face the six support pins 75 and the six reflecting portions 377. The laser light source 21 emits laser light in a wavelength region (1.1 μm or less) that is transmitted by quartz and absorbed by silicon.

  In the fourth embodiment, each of the six laser light sources 21 emits laser light in parallel to the upper surface and the bottom surface of the susceptor 74 toward the corresponding reflecting portion 377. The laser light emitted from the laser light source 21 enters the reflecting portion 377 and reaches the reflecting surface 377a. At this time, since the laser light is incident on the reflecting surface 377a at an incident angle larger than the critical angle from quartz to air, it is totally reflected by the reflecting surface 377a. Then, the laser beam totally reflected by the reflecting surface 377a travels toward the support pin 75 and reaches the vicinity of the contact point with the support pin 75 of the semiconductor wafer W.

  In the vicinity of the contact point of the semiconductor wafer W with the support pins 75, the laser beam is absorbed and the temperature rises. Such auxiliary heating in the vicinity of the contact point with the support pin 75 by laser light irradiation is performed for each of the six support pins 75. As a result, the vicinity of the contact point between the six support pins 75 and the semiconductor wafer W is individually heated to increase the temperature, and the temperature in the surface of the semiconductor wafer W during the preheating is uniformed by preventing the temperature from decreasing. Can be. As a result, the in-plane temperature distribution on the surface of the semiconductor wafer W during flash heating can be made uniform.

  Further, as in the third embodiment, the reflection portion 377 has a shape that is line symmetric about the central axis of the support pin 75. Therefore, even if the laser light is incident from any direction around the reflecting portion 377, the laser light is reflected by the reflecting surface 377a and guided to the support pin 75. For this reason, the freedom degree of the incident direction of the laser beam by the laser light source 21 becomes high.

  Furthermore, in the fourth embodiment, since the reflecting portion 377 has a convex reflecting surface 377a, a laser beam having a predetermined width is guided to the support pin 75 so as to be reflected by the reflecting surface 377a and spread. . For this reason, compared with 1st Embodiment to 3rd Embodiment, the wide range of a contact location vicinity can be heated. That is, when the temperature drops over a relatively wide range in the vicinity of the contact point with the support pin 75 of the semiconductor wafer W, the reflecting portion 377 having the convex reflecting surface 377a as in the fourth embodiment is suitable. .

<Fifth Embodiment>
Next, a fifth embodiment of the present invention will be described. The overall configuration of the heat treatment apparatus of the fifth embodiment is substantially the same as that of the first embodiment. The processing procedure for the semiconductor wafer W in the heat treatment apparatus of the fifth embodiment is also the same as that of the first embodiment. The fifth embodiment differs from the first embodiment in the structure of the reflecting portion formed on the susceptor 74.

  FIG. 13 is a diagram illustrating the reflecting portion 477 of the fifth embodiment. The reflective portion 477 of the fifth embodiment is a quartz convex portion protruding from the bottom surface of the susceptor 74. The reflecting portion 477 has a shape that is line symmetric about the central axis of the support pin 75. Specifically, the reflecting portion 477 of the fifth embodiment has a concave reflecting surface 477a. The concave shape here is a shape of a curved surface that is concave when viewed from the support pin 75 side. Such a line-symmetric reflecting portion 477 is provided corresponding to each of the six support pins 75.

  Similarly to the first embodiment, six laser light sources 21 are installed on the side of the susceptor 74 so as to face the six support pins 75 and the six reflecting portions 477. The laser light source 21 emits laser light in a wavelength region (1.1 μm or less) that is transmitted by quartz and absorbed by silicon.

  In the fifth embodiment, each of the six laser light sources 21 emits laser light in parallel to the upper surface and the bottom surface of the susceptor 74 toward the corresponding reflecting portion 477. The laser light emitted from the laser light source 21 enters the reflection portion 477 and reaches the reflection surface 477a. At this time, since the laser light is incident on the reflection surface 477a at an incident angle larger than the critical angle from quartz to air, it is totally reflected by the reflection surface 477a. Then, the laser beam totally reflected by the reflecting surface 477a travels toward the support pin 75 and reaches the vicinity of the contact point with the support pin 75 of the semiconductor wafer W.

  In the vicinity of the contact point of the semiconductor wafer W with the support pins 75, the laser beam is absorbed and the temperature rises. Such auxiliary heating in the vicinity of the contact point with the support pin 75 by laser light irradiation is performed for each of the six support pins 75. As a result, the vicinity of the contact point between the six support pins 75 and the semiconductor wafer W is individually heated to increase the temperature, and the temperature in the surface of the semiconductor wafer W during the preheating is uniformed by preventing the temperature from decreasing. Can be. As a result, the in-plane temperature distribution on the surface of the semiconductor wafer W during flash heating can be made uniform.

  Similarly to the third embodiment, the reflecting portion 477 has a shape that is line-symmetric about the central axis of the support pin 75. Therefore, even if the laser light is incident from any direction around the reflecting portion 477, the laser light is reflected by the reflecting surface 477a and guided to the support pin 75. For this reason, the freedom degree of the incident direction of the laser beam by the laser light source 21 becomes high.

  Furthermore, in the fifth embodiment, since the reflecting portion 477 has the concave reflecting surface 477a, the laser light having a predetermined width is guided to the support pin 75 so as to be reflected and focused by the reflecting surface 477a. It is burned. For this reason, compared with 1st Embodiment to 3rd Embodiment, the narrow range near a contact location can be heated intensively. That is, when a large temperature drop occurs in a relatively narrow range near the contact point with the support pins 75 of the semiconductor wafer W as compared with the peripheral region, the concave reflection surface 477a as in the fifth embodiment is provided. The reflection part 477 is suitable.

<Sixth Embodiment>
Next, a sixth embodiment of the present invention will be described. The overall configuration of the heat treatment apparatus of the sixth embodiment is substantially the same as that of the first embodiment. The processing procedure for the semiconductor wafer W in the heat treatment apparatus of the sixth embodiment is also the same as that of the first embodiment. The sixth embodiment differs from the first embodiment in the structure of the reflecting portion formed on the susceptor 74.

  FIG. 14 is a diagram illustrating a reflecting unit according to the sixth embodiment. In the third to fifth embodiments, the line-symmetrical convex portion is formed as the reflecting portion on the bottom surface of the susceptor 74, but in the sixth embodiment, the line-symmetric concave portion is reflected on the bottom surface of the susceptor 74. Provided as part. Each of the reflecting portion 577 in FIG. 14A and the reflecting portion 578 in FIG. 14B has a shape that is axisymmetric about the central axis of the support pin 75. Specifically, the reflecting portion 577 in FIG. 14A has a conical reflecting surface 577a, and the reflecting portion 578 in FIG. 14B has a convex reflecting surface 578a. That is, the reflective portion 577 in FIG. 14A is a concave portion of the convex portion of the third embodiment, and the reflective portion 578 of FIG. 14B is a concave portion of the convex portion of the fourth embodiment. It can be said that there is.

  Similarly to the first embodiment, six laser light sources 21 are disposed on the side of the susceptor 74 so as to face the six support pins 75 and the six reflecting portions 577 and 578. The laser light source 21 emits laser light in a wavelength region (1.1 μm or less) that is transmitted by quartz and absorbed by silicon.

  In the fifth embodiment, each of the six laser light sources 21 emits laser light in parallel to the upper surface and the bottom surface of the susceptor 74 toward the corresponding reflecting portions 577 and 578. The laser light emitted from the laser light source 21 enters the reflection portions 577 and 578 and reaches the reflection surfaces 577a and 578a. At this time, since the laser light is incident on the reflecting surfaces 577a and 578a at an incident angle larger than the critical angle, it is totally reflected by the reflecting surfaces 577a and 578a. Then, the laser light totally reflected by the reflection surfaces 577a and 578a goes to the support pins 75 and reaches the vicinity of the contact point with the support pins 75 of the semiconductor wafer W.

  In the vicinity of the contact point of the semiconductor wafer W with the support pins 75, the laser beam is absorbed and the temperature rises. Such auxiliary heating in the vicinity of the contact point with the support pin 75 by laser light irradiation is performed for each of the six support pins 75. As a result, the vicinity of the contact point between the six support pins 75 and the semiconductor wafer W is individually heated to increase the temperature, and the temperature in the surface of the semiconductor wafer W during the preheating is uniformed by preventing the temperature from decreasing. Can be. As a result, the in-plane temperature distribution on the surface of the semiconductor wafer W during flash heating can be made uniform.

  Moreover, according to the reflection part 577 of FIG. 14A, the same effect as the reflection part 277 of the third embodiment can be obtained, and according to the reflection part 578 of FIG. 14B, the reflection of the fourth embodiment. The same effect as the part 377 can be obtained.

<Seventh embodiment>
Next, a seventh embodiment of the present invention will be described. The overall configuration of the heat treatment apparatus of the seventh embodiment is substantially the same as that of the first embodiment. The processing procedure for the semiconductor wafer W in the heat treatment apparatus of the seventh embodiment is also the same as that of the first embodiment. The seventh embodiment differs from the first embodiment in the structure of the reflecting portion and the support pin provided on the susceptor 74.

  FIG. 15 is a diagram illustrating a reflecting portion and a support pin according to the seventh embodiment. Similar to the sixth embodiment, the bottom surface of the susceptor 74 is provided with a line-symmetric recess as a reflection portion. In the seventh embodiment, a support pin having the same shape as the reflecting portion is erected on the upper surface of the susceptor 74. That is, the shape of the reflection portion provided on the bottom surface of the susceptor 74 is the same as that of the support pin provided on the top surface.

  In the example of FIG. 15A, a reflecting portion 677 having a conical reflecting surface 677 a is formed on the bottom surface of the susceptor 74. A conical support pin 175 is provided on the upper surface of the susceptor 74. In the example of FIG. 15B, a reflecting portion 678 having a convex reflecting surface 678a is formed on the bottom surface of the susceptor 74. A convex support pin 275 is provided on the upper surface of the susceptor 74. Further, in the example of FIG. 15C, a reflecting portion 679 having a concave reflecting surface 679 a is formed on the bottom surface of the susceptor 74. A concave support pin 375 is provided on the upper surface of the susceptor 74.

  15A to 15C, the support pins 175, 275, 375 and the reflecting portions 677, 678, 679 have the same shape and the same size. For example, six support pins 175, 275, 375 are provided on the upper surface of the susceptor 74. Reflecting portions 677, 678, and 679 are provided corresponding to the six support pins 175, 275, and 375, respectively. The reflection parts 677, 678, and 679 have shapes that are line symmetric with respect to the center axis of the support pins 175, 275, and 375. That is, the central axes of the reflecting portions 677, 678, and 679 coincide with the central axes of the support pins 175, 275, and 375.

  As in the first embodiment, six laser light sources 21 are installed on the side of the susceptor 74. The laser light source 21 emits laser light in a wavelength region (1.1 μm or less) that is transmitted by quartz and absorbed by silicon.

  In the seventh embodiment, each of the six laser light sources 21 emits laser light in parallel to the upper surface and the bottom surface of the susceptor 74 toward the corresponding reflecting portions 677, 678, 679. The laser light emitted from the laser light source 21 enters the reflecting portions 677, 678, 679 and reaches the reflecting surfaces 677a, 678a, 679a. At this time, since the laser light is incident on the reflecting surfaces 677a, 678a, and 679a at an incident angle larger than the critical angle, it is totally reflected by the reflecting surfaces 677a, 678a, and 679a. The laser light totally reflected by the reflecting surfaces 677a, 678a, and 679a travels toward the support pins 175, 275, and 375 and reaches the vicinity of the contact point of the semiconductor wafer W with the support pins 175, 275, and 375.

  In the vicinity of the contact portion of the semiconductor wafer W with the support pins 175, 275, and 375, the laser beam is absorbed and the temperature rises. The auxiliary heating in the vicinity of the contact point with the support pins 175, 275, 375 by the laser light irradiation is performed for each of the six support pins 175, 275, 375. As a result, the vicinity of the contact portion between the six support pins 175, 275, 375 and the semiconductor wafer W is individually heated to increase the temperature, and the temperature of the semiconductor wafer W is prevented from being lowered to prevent in-plane of the semiconductor wafer W during preheating. The temperature distribution can be made uniform. As a result, the in-plane temperature distribution on the surface of the semiconductor wafer W during flash heating can be made uniform.

  In the seventh embodiment, support pins 175, 275, and 375 having the same shape as the reflecting portions 677, 678, and 679 that are concave portions are erected on the upper surface of the susceptor 74. The central axes of the reflecting portions 677, 678, and 679 coincide with the central axes of the support pins 175, 275, and 375. For this reason, the thickness is constant over the entire surface of the susceptor 74 including the support pins 175, 275, and 375. As a result, the heat capacity in the thickness direction becomes uniform over the entire surface of the susceptor 74, and the in-plane temperature distribution of the semiconductor wafer W during preheating can be made more uniform.

<Eighth Embodiment>
Next, an eighth embodiment of the present invention will be described. In the first to seventh embodiments, the laser light source 21 is provided as an auxiliary irradiation unit. However, in the eighth embodiment, a halogen lamp 121 is provided as an auxiliary irradiation unit in place of the laser light source. FIG. 16 is a diagram illustrating an example in which a halogen lamp 121 is provided as an auxiliary irradiation unit. The susceptor 74 of the eighth embodiment is the same as that of the first embodiment. That is, as in the first embodiment, the bottom surface of the susceptor 74 is formed with a reflecting portion 77 that is a recess. A support pin 75 is erected on the upper surface of the susceptor 74.

  In the eighth embodiment, an annular halogen lamp 121 is installed on the side of the susceptor 74. The inner diameter of the annular halogen lamp 121 is larger than the diameter of the susceptor 74. Therefore, the halogen lamp 121 is provided in an annular shape so as to surround the periphery of the susceptor 74. The halogen lamp 121 is a continuous lighting lamp that emits light on the same principle as the halogen lamp HL of the halogen heating unit 4.

  In the eighth embodiment, the halogen lamp 121 emits light and irradiates light from the side of the susceptor 74. However, since the halogen lamp 121 emits light from the entire circumference of the glass tube, in addition to light traveling in parallel with the upper surface and the bottom surface of the susceptor 74, light traveling in other directions is also emitted. Of the light emitted from the halogen lamp 121, the light traveling in parallel with the top and bottom surfaces of the susceptor 74 is totally reflected by the reflecting surface 77a and guided to the support pin 75, as in the first embodiment. As a result, the vicinity of the contact portion between the six support pins 75 and the semiconductor wafer W is heated to increase the temperature, and the temperature in the surface of the semiconductor wafer W during preheating is made uniform by preventing the temperature from decreasing. be able to. As a result, the in-plane temperature distribution on the surface of the semiconductor wafer W during flash heating can be made uniform.

  Further, since the halogen lamp 121 is provided in an annular shape so as to surround the periphery of the susceptor 74, a part of the light emitted from the halogen lamp 121 is the end of the semiconductor wafer W supported by the susceptor 74. The edge is irradiated directly. Thereby, the edge part of the semiconductor wafer W which is likely to cause a temperature drop during preheating can be heated to make the in-plane temperature distribution of the semiconductor wafer W more uniform.

<Modification>
While the embodiments of the present invention have been described above, the present invention can be modified in various ways other than those described above without departing from the spirit of the present invention. For example, in the first to seventh embodiments, the six laser light sources 21 are provided so as to face the six support pins 75 and the six reflecting portions. However, the present invention is not limited to this. Alternatively, six laser light sources may be provided at one location inside the side wall of the chamber 6 so as to emit laser light toward the six reflecting portions. In particular, as in the third to seventh embodiments, in the case where a reflecting portion having a shape that is axisymmetric about the central axis of the support pin is provided, the laser is emitted from any direction around the reflecting portion. Even if light is incident, the laser light is totally reflected and guided to the support pin, so that the degree of freedom of the installation position of the laser light source is high.

  In the eighth embodiment, the halogen lamp 121 is provided on the side of the susceptor 74, but an arc lamp may be provided as an auxiliary irradiation unit. Or you may make it arrange | position the rod-shaped lamp | ramp similar to the halogen lamp HL of the halogen heating part 4 in the four sides of the susceptor 74 side.

  In each of the above embodiments, the number of support pins is six. However, the number of support pins is not limited to this, and the number of support pins standing on the upper surface of the susceptor 74 is three that can support the semiconductor wafer W. That is all you need. Depending on the number of support pins standing on the upper surface of the susceptor 74, the number of reflecting portions provided on the bottom surface is also set to be the same.

  In each of the above embodiments, light is incident on the reflecting surface of the reflecting portion at an incident angle larger than the critical angle. Instead, a metal film is formed on the reflecting surface to form a mirror surface. Thus, incident light may be reflected. Although the metal film is generally inferior in heat resistance to quartz, the incident angle does not necessarily have to be larger than the critical angle if the reflecting surface is a mirror surface, which is particularly suitable when the processing temperature is low.

  Further, in the sixth embodiment, a reflecting portion may be formed on the bottom surface of the susceptor 74 using the concave convex portion as in the fifth embodiment as a concave portion (see FIG. 15C).

  In the eighth embodiment, the susceptor 74 may be as shown in the second to seventh embodiments. In particular, since the susceptor 74 shown in the third to seventh embodiments is provided with a reflecting portion having a line-symmetric shape around the central axis of the support pin, the susceptor 74 can be viewed from any direction around the reflecting portion. The incident light can also be guided to the support pin. For this reason, the light emitted from the entire circumference of the halogen lamp 121 provided in an annular shape can be efficiently reflected and guided to the support pin.

  In each of the above embodiments, the flash heating unit 5 is provided with 30 flash lamps FL. However, the present invention is not limited to this, and the number of flash lamps FL may be an arbitrary number. it can. The flash lamp FL is not limited to a xenon flash lamp, and may be a krypton flash lamp. Further, the number of halogen lamps HL provided in the halogen heating unit 4 is not limited to 40, and may be any number as long as a plurality of halogen lamps HL are arranged in the upper and lower stages.

  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.

  Further, the heat treatment technique according to the present invention is not limited to the flash lamp annealing apparatus, but is also applied to a heat source apparatus other than a flash lamp such as a single wafer type lamp annealing apparatus or a CVD apparatus using a halogen lamp. be able to. In particular, the technique according to the present invention is suitable for a backside annealing apparatus in which a halogen lamp is disposed below the chamber and heat treatment is performed by irradiating light from the back surface of a semiconductor wafer supported by a plurality of support pins on a quartz susceptor. Can be applied.

DESCRIPTION OF SYMBOLS 1 Heat processing apparatus 3 Control part 4 Halogen heating part 5 Flash heating part 6 Chamber 7 Holding part 10 Transfer mechanism 21
65 Heat treatment space 74 Susceptor 75, 175, 275, 375 Support pin 77, 177, 277, 377, 477, 577, 578, 677, 678, 679 Reflection part 77a, 177a, 277a, 377a, 477a, 577a, 578a, 677a , 678a, 679a Reflecting surface 121, HL Halogen lamp FL Flash lamp W Semiconductor wafer

Claims (9)

A heat treatment apparatus for heating a substrate by irradiating the substrate with light,
A chamber for housing the substrate;
A plurality of support pins are erected on the first surface, and a quartz plate-shaped susceptor that supports a substrate with the plurality of support pins in the chamber;
A light irradiator that irradiates light through the susceptor through a substrate supported by the susceptor;
An auxiliary irradiator provided on the side of the susceptor;
With
A reflection part that reflects the light emitted from the auxiliary irradiation part toward the support pin is provided on the second surface of the susceptor ;
The reflecting portion is a recess formed on the second surface of the susceptor;
The heat treatment apparatus , wherein the reflection portion has the same shape as each of the plurality of support pins . A heat treatment apparatus for heating a substrate by irradiating the substrate with light,
A chamber for housing the substrate;
A plurality of support pins are erected on the first surface, and a quartz plate-shaped susceptor that supports a substrate with the plurality of support pins in the chamber;
A light irradiator that irradiates light through the susceptor through a substrate supported by the susceptor;
An auxiliary irradiator provided on the side of the susceptor;
With
A reflection part that reflects the light emitted from the auxiliary irradiation part toward the support pin is provided on the second surface of the susceptor;
The reflecting portion, Ri recess der which is Katachi設the second surface of the susceptor,
The heat treatment apparatus , wherein the reflection portion has a shape that is line-symmetric about a central axis of each of the plurality of support pins . The heat treatment apparatus according to claim 2 ,
The heat treatment apparatus, wherein the reflection portion has a conical reflection surface. The heat treatment apparatus according to claim 2 ,
The said reflection part has a convex-shaped reflective surface, The heat processing apparatus characterized by the above-mentioned. The heat treatment apparatus according to claim 2 ,
The said reflection part has a concave-shaped reflection surface, The heat processing apparatus characterized by the above-mentioned. In the heat processing apparatus in any one of Claims 1-5 ,
The auxiliary irradiation unit includes a laser light source that emits laser light. The heat treatment apparatus according to claim 6 , wherein
The heat treatment apparatus, wherein the laser light source emits laser light parallel to the first surface and the second surface of the susceptor. In the heat processing apparatus in any one of Claims 1-5 ,
The auxiliary irradiation section includes a halogen lamp. The heat treatment apparatus according to claim 8 , wherein
The heat treatment apparatus, wherein the halogen lamp is provided in an annular shape so as to surround the periphery of the susceptor.

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