JP2016171276A - Heat treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat treatment device which can unify an in-plane temperature distribution of a substrate.SOLUTION: A heat treatment device comprises: a plurality of halogen lamps HL for emitting halogen light to a semiconductor wafer W held by a holding part in a chamber to heat the semiconductor wafer W; and a cylindrical louver 21 and an annular light shielding ring 25 which are provided between the halogen lamps HL and the semiconductor wafer W, and formed by opaque quartz. The outside diameter of the light-shielding ring 25 is smaller than the inside diameter of the louver 21. Light emitted from the halogen lamps HL and transmitted through a gap generated between an internal surface of the louver 21 and an outer periphery of the light shielding ring 25 is irradiated on a circumference of the semiconductor wafer W, where temperature drop easily occurs. Meanwhile, light toward a region slightly inside the circumference of the semiconductor wafer W, which is likely to become high temperature only by the louver 21, is shielded by the light shielding ring 25.SELECTED DRAWING: Figure 10

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 disk-shaped 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, in Patent Documents 1 and 2, a pulse emitting lamp such as a flash lamp is arranged on the front side of a semiconductor wafer, and a continuous lighting lamp such as a halogen lamp is arranged on the back side. And what performs desired heat processing by those combination is disclosed. In the heat treatment apparatuses disclosed in Patent Documents 1 and 2, the semiconductor wafer is preheated to a certain temperature with a halogen lamp or the like, and then heated to a desired processing temperature by pulse heating from a flash lamp.

  When preheating is performed with a halogen lamp as disclosed in Patent Documents 1 and 2, there is a merit in the process that the semiconductor wafer can be heated to a relatively high preheating temperature in a short time. However, there is a problem that the temperature at the peripheral edge of the wafer is lower than that at the center. Possible causes of such non-uniform temperature distribution include heat radiation from the peripheral edge of the semiconductor wafer or heat conduction from the peripheral edge of the semiconductor wafer to a relatively low temperature quartz susceptor. Therefore, in order to solve such a problem, Patent Document 3 discloses that a cylindrical louver formed of a semi-transparent material is installed between a halogen lamp and a semiconductor wafer to perform in-plane pre-heating. It has been proposed to make the temperature distribution uniform.

JP-A-60-258928 JP 2005-527972 A JP 2012-174879 A

  However, when the louver as proposed in Patent Document 3 is provided, the temperature drop at the peripheral portion of the semiconductor wafer is improved, but a new problem that the region slightly inside the peripheral portion becomes high on the contrary Was found to occur.

  The present invention has been made in view of the above problems, and an object thereof is to provide a heat treatment apparatus capable of making the in-plane temperature distribution of a substrate uniform.

  In order to solve the above-mentioned problems, a first aspect of the present invention is a heat treatment apparatus for heating a substrate by irradiating a disk-shaped substrate with a chamber for accommodating the substrate, and a substrate in the chamber. A light irradiating unit in which a plurality of rod-shaped lamps are arranged in a region facing the main surface wider than the main surface of the substrate held by the holding unit, the light irradiating unit, and the holding unit. A central axis passing through the center of the substrate, and a cylindrical light-shielding member opaque to the light emitted from the light irradiation unit, the light irradiation unit and the holding unit A flat plate-shaped second light shielding member that is opaque with respect to the light emitted from the light irradiating portion, and has a central axis that passes through the center of the substrate. The outer size is the size inside the first light shielding member. And wherein the small.

  According to a second aspect of the present invention, in the heat treatment apparatus according to the first aspect of the invention, the second light shielding member has an annular shape, and the outer diameter of the second light shielding member is larger than the inner diameter of the first light shielding member. Is also small.

  According to a third aspect of the present invention, in the heat treatment apparatus according to the first or second aspect of the invention, the second light shielding member is placed on a quartz plate provided on the first light shielding member. It is characterized by that.

  According to a fourth aspect of the invention, in the heat treatment apparatus according to the first or second aspect of the invention, the second light shielding member is placed on a quartz window of the chamber facing the light irradiation unit. It is characterized by that.

  In a fifth aspect of the present invention, in the heat treatment apparatus according to the first or second aspect of the invention, the first light shielding member is placed on the second light shielding member inside the first light shielding member. It is mounted on a quartz stage.

  The invention of claim 6 is the heat treatment apparatus according to claim 3, wherein the quartz plate has the same outer diameter and inner diameter as the first light shielding member, and is emitted from the light irradiation section. A cylindrical third light-shielding member that is opaque to light is further provided.

  According to the first to sixth aspects of the present invention, the opaque first cylindrical light shielding member and the opaque flat plate-shaped second light shielding member are provided, and the outer size of the second light shielding member is the first light shielding member. Since the first light shielding member and the second light shielding member block a part of the light traveling from the light irradiation unit to the substrate, the in-plane temperature distribution of the substrate can be made uniform.

It is a longitudinal cross-sectional view which shows the structure of the heat processing apparatus which concerns on this invention. It is 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 the side view which looked at the holding | maintenance part from the side. 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 perspective view of a louver. It is a perspective view which shows the whole external appearance of the louver and light-shielding ring in 1st Embodiment. It is a figure which shows the optical path adjustment by the louver and the light shielding ring in 1st Embodiment. It is a figure which shows arrangement | positioning of the louver and light-shielding ring in 2nd Embodiment. It is a figure which shows arrangement | positioning of the louver and light-shielding ring in 3rd Embodiment. It is a figure which shows arrangement | positioning of the louver and light-shielding ring in 4th Embodiment. It is a figure which shows the in-plane temperature distribution of the semiconductor wafer in the case of installing only a louver.

  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 this embodiment is a flash lamp annealing apparatus that heats a semiconductor wafer W by irradiating flash light onto a disk-shaped semiconductor wafer W having a diameter of 300 mm as a substrate. 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. A louver (first light shielding member) 21 and a light shielding ring (second light shielding member) 25 are provided between the halogen heating unit 4 and the chamber 6. 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 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 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 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, and FIG. 4 is a side view of the holding unit 7 as viewed from the side. 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 substantially circular flat plate member made of quartz. 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. On the upper surface of the susceptor 74, a plurality (five in this embodiment) of guide pins 76 are erected. The five guide pins 76 are provided along a circumference that is concentric with the outer circumference of the susceptor 74. 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. The guide pin 76 may be processed from a quartz ingot integrally with the susceptor 74, or a separately processed one may be attached to the susceptor 74 by welding or the like.

  The four connecting portions 72 erected on the base ring 71 and the lower surface of the peripheral 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, and the holding portion 7 is an integrally formed member of quartz. 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 in which the holding unit 7 is mounted on the chamber 6, the substantially disc-shaped 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 held in a horizontal posture on the susceptor 74 of the holding unit 7 attached to the chamber 6. The semiconductor wafer W is placed inside a circle formed by the five guide pins 76, thereby preventing a horizontal displacement. Note that the number of guide pins 76 is not limited to five, and may be any number that can prevent misalignment of the semiconductor wafer W.

  As shown in FIGS. 2 and 3, the susceptor 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 to receive radiation light (infrared light) emitted from the lower surface of the semiconductor wafer W held by the susceptor 74 by the radiation thermometer 120. 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.

  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 position indicated by a solid line 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 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.

  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.

  The halogen heating unit 4 provided below the chamber 6 incorporates a plurality (40 in this embodiment) of halogen lamps HL inside the housing 41. The halogen heating unit 4 is a light irradiation unit that heats the semiconductor wafer W by irradiating the heat treatment space 65 from below the chamber 6 through the lower chamber window 64 with a plurality of halogen lamps HL.

  FIG. 7 is a plan view showing the arrangement of the plurality of halogen lamps HL. In the first embodiment, a plurality of halogen lamps HL are arranged in a region wider than the main surface of the disk-shaped semiconductor wafer W held by the holding unit 7 (that is, a circle having a diameter of 300 mm). A plurality of halogen lamps HL are arranged in a region facing the lower surface of the main surface of the semiconductor wafer W.

  As shown in FIGS. 1 and 7, in the first embodiment, 40 halogen lamps HL are arranged in two upper and lower stages. Twenty halogen lamps HL are arranged on the upper stage close to the holding unit 7, and twenty halogen lamps HL are arranged on the lower stage farther from the holding unit 7 than the upper stage. 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. 7, 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 stage and the lower stage. 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 20 halogen lamps HL arranged in the upper stage and the longitudinal direction of the 20 halogen lamps HL arranged in the lower stage are orthogonal to each other. Yes.

  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, a reflector 43 is also provided in the housing 41 of the halogen heating unit 4 below the two-stage halogen lamp HL (FIG. 1). The reflector 43 reflects the light emitted from the plurality of halogen lamps HL toward the heat treatment space 65.

  A louver 21 and a light shielding ring 25 are provided between the halogen heating unit 4 and the holding unit 7. FIG. 8 is a perspective view of the louver 21. The louver 21 is a cylindrical (bottomless cylindrical) member having open ends on the top and bottom. The louver 21 is made of a material that is opaque to the light emitted from the halogen lamp HL of the halogen heating unit 4, and is made of, for example, opaque quartz in which many fine bubbles are included in quartz glass. . The size of the louver 21 can be set appropriately according to the arrangement configuration of the chamber 6 and the halogen heating unit 4. The outer diameter of the cylinder of the louver 21 only needs to be smaller than the region where the halogen lamp HL is disposed. For example, in the first embodiment, the outer diameter of the louver 21 is 300 mm, which is the same as the diameter of the semiconductor wafer W, and the inner diameter is 294 mm. Further, the height of the louver 21 may be, for example, 15 mm to 25 mm (16 mm in the first embodiment).

  As shown in FIG. 1, a louver stage 22 is provided at the upper end of the casing 41 of the halogen heating unit 4. The louver stage 22 is a flat plate member made of quartz glass that is transparent to light emitted from the halogen lamp HL. A louver 21 is installed on the upper surface of the louver stage 22. The louver 21 is provided so that the central axis CX of the cylinder passes through the center of the semiconductor wafer W held by the holding unit 7. The plurality of halogen lamps HL of the halogen heating unit 4 are arranged in a region facing the lower surface of the semiconductor wafer W held by the holding unit 7. Therefore, the central axis CX of the louver 21 also passes through the center of the arrangement of the plurality of halogen lamps HL.

  By providing the cylindrical louver 21 made of opaque quartz in this manner between the halogen heating unit 4 and the chamber 6, when light is irradiated from a plurality of halogen lamps HL, the outer side is outside the louver 21. Light directed from the halogen lamp HL provided to the inner region including the vicinity of the central portion of the semiconductor wafer W (the region inside the peripheral portion) is blocked by the wall surface of the opaque louver 21. On the other hand, light traveling from the halogen lamp HL provided outside the louver 21 toward the peripheral edge of the semiconductor wafer W is not shielded. As a result, by providing the louver 21, the light traveling from the halogen heating unit 4 toward the peripheral edge of the semiconductor wafer W hardly decreases, whereas the light traveling toward the inner region decreases and the heating of the inner region is weakened. Thus, the peripheral edge portion of the semiconductor wafer W, which is likely to cause a temperature drop, is heated relatively strongly.

  However, when the inventors of the present application have conducted an intensive investigation, if only the louver 21 is installed above the halogen heating unit 4, it is slightly more than the peripheral edge of the semiconductor wafer W during light irradiation heating by a plurality of halogen lamps HL. It has been found that a new problem arises that the inner region becomes hot on the contrary. FIG. 14 is a diagram showing the in-plane temperature distribution of the semiconductor wafer W when only the louver 21 is installed. If only the louver 21 is installed and light is irradiated from a plurality of halogen lamps HL, as shown in the figure, a high temperature region (hot) that is slightly higher in temperature than other regions slightly inside the peripheral edge of the semiconductor wafer W. Spot) 99 appears.

  Therefore, in the present invention, a light shielding ring 25 is provided between the halogen heating unit 4 and the holding unit 7 in addition to the louver 21. FIG. 9 is a perspective view showing the overall appearance of the louver 21 and the light shielding ring 25 in the first embodiment. A ring stage 24 is installed at the upper end of the cylindrical louver 21. The ring stage 24 is a disk-shaped member made of quartz glass that is transparent to light emitted from the halogen lamp HL. The diameter of the ring stage 24 is the same as the outer diameter of the louver 21 (300 mm in this embodiment). The plate thickness of the ring stage 24 is 2 mm to 3 mm.

  A light shielding ring 25 is placed on the upper surface of the ring stage 24. That is, in the first embodiment, the light shielding ring 25 is further placed on the ring stage 24 that is a quartz plate provided on the louver 21. The light shielding ring 25 is an annular flat plate member. The light shielding ring 25 is formed of a material that is opaque to light emitted from the halogen lamp HL of the halogen heating unit 4, and is formed of, for example, opaque quartz in which many fine bubbles are included in quartz glass. Yes. In the first embodiment, the louver 21 and the light shielding ring 25 are formed of the same material.

  The outer diameter of the annular light shielding ring 25 is smaller than the inner diameter of the cylindrical louver 21 and is, for example, 280 mm in the first embodiment. That is, the outer size of the light shielding ring 25 is smaller than the size inside the louver 21. The inner diameter of the light shielding ring 25 is, for example, 260 mm, and the plate thickness of the light shielding ring 25 is, for example, 2 mm.

  The central axis CX of the louver 21 coincides with the central axis of the annular light shielding ring 25. Accordingly, the light shielding ring 25 is also provided so that the center axis of the annular shape passes through the center of the semiconductor wafer W held by the holding unit 7.

  Returning to FIG. 1, the control unit 3 controls the various operating 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.

  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.

  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 held by the holding unit 7 with the surface on which the pattern is formed and impurities are implanted as the upper surface. The semiconductor wafer W is held inside the five guide pins 76 on the upper surface of the susceptor 74. 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 held horizontally from below by the holding unit 7 made of quartz, the 40 halogen lamps HL of the halogen heating unit 4 are turned on all at once and preheating (assist heating) is started. Is done. The halogen light emitted from the halogen lamp HL is transmitted through the louver stage 22, the ring stage 24, the lower chamber window 64 and the susceptor 74 made of quartz, and the rear surface of the semiconductor wafer W (the main surface opposite to the front surface). Irradiated from the surface). 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 the contact thermometer 130. That is, a contact thermometer 130 incorporating a thermocouple contacts the lower surface of the semiconductor wafer W held by the holding unit 7 via the notch 77 of the susceptor 74 to measure the temperature of the wafer being heated. The measured temperature of the semiconductor wafer W is transmitted 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. . Note that when the temperature of the semiconductor wafer W is increased by light irradiation from the halogen lamp HL, temperature measurement by the radiation thermometer 120 is not performed. This is because the halogen light irradiated from the halogen lamp HL enters the radiation thermometer 120 as disturbance light, and accurate temperature measurement cannot be performed.

  In the first embodiment, an opaque cylindrical louver 21 and an annular light shielding ring 25 are provided between the halogen heating unit 4 and the chamber 6, and the halogen heating unit 4 holds the holding unit 7. A part of the light traveling toward the semiconductor wafer W is blocked. FIG. 10 is a diagram illustrating optical path adjustment by the louver 21 and the light shielding ring 25 in the first embodiment.

  As described above, in this embodiment, a plurality of halogen lamps HL are arranged in a region wider than the main surface of the disk-shaped semiconductor wafer W, and the outer diameter of the louver 21 is the same as the diameter of the semiconductor wafer W. is there. Accordingly, the halogen lamp HL also exists outside the cylindrical louver 21. For this reason, the light directed from the halogen lamp HL provided outside the louver 21 toward the inner region (region inside the peripheral portion) including the vicinity of the center portion of the semiconductor wafer W is shielded by the wall surface of the opaque louver 21. . On the other hand, light traveling from the halogen lamp HL provided outside the louver 21 toward the peripheral edge of the semiconductor wafer W is not shielded.

  The central axis of the light shielding ring 25 coincides with the central axis CX of the louver 21, and the outer diameter of the light shielding ring 25 is smaller than the inner diameter of the louver 21. Therefore, as shown in FIG. 10, there is a gap through which light emitted from the halogen lamp HL can pass between the inner wall surface of the louver 21 and the outer periphery of the light shielding ring 25. In the first embodiment, since the inner diameter of the louver 21 is 294 mm and the outer diameter of the light shielding ring 25 is 280 mm, an annular gap having a width of 7 mm is generated between the inner wall surface of the louver 21 and the outer periphery of the light shielding ring 25. It will be. Further, since the outer diameter of the louver 21 is the same as the diameter of the semiconductor wafer W held by the holding part 7, the gap exists immediately below the peripheral edge of the semiconductor wafer W. Accordingly, as shown in FIG. 10, the light emitted from the halogen lamp HL and transmitted through the gap formed between the inner wall surface of the louver 21 and the outer periphery of the light shielding ring 25 is reflected on the semiconductor wafer W held by the holding unit 7. Irradiates the peripheral edge. Thereby, combined with the light shielding effect by the louver 21 described above, the illuminance at the peripheral portion of the semiconductor wafer W due to light irradiation from the halogen lamp HL becomes relatively high, and the peripheral portion that is likely to cause a temperature drop is strongly heated. The Rukoto.

  On the other hand, the opaque annular light-shielding ring 25 has an outer diameter of 280 mm and an inner diameter of 260 mm. Therefore, only the region slightly inside the peripheral edge of the semiconductor wafer W held by the holding unit 7, that is, only the louver 21. 14 is present below the high temperature region 99 shown in FIG. Accordingly, as shown in FIG. 10, the light emitted from the halogen lamp HL and traveling toward a region slightly inside the peripheral edge of the semiconductor wafer W is shielded by the light shielding ring 25. As a result, the illuminance in the high temperature region 99 of the semiconductor wafer W that appears when only the louver 21 is installed becomes relatively low, and the heating of the high temperature region 99 is weakened.

  In this way, the combination of the louver 21 and the light shielding ring 25 increases the illuminance at the peripheral portion of the semiconductor wafer W due to light irradiation from the halogen lamp HL, while decreasing the illuminance at the region slightly inside the peripheral portion. As a result, while the peripheral edge of the semiconductor wafer W, which is susceptible to temperature drop, is heated relatively strongly, the heating of the region slightly inside the peripheral edge where the temperature is high only by the louver 21 is relatively weak, Nonuniformity of the in-plane temperature distribution of the semiconductor wafer W during preheating can be effectively eliminated.

  When a predetermined time elapses after the temperature of the semiconductor wafer W reaches the preheating temperature T1, the flash lamp FL of the flash heating unit 5 irradiates the surface of the semiconductor wafer W with flash light. 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 louver 21 and the light shielding ring 25 shield a part of the light from the halogen heating unit 4 toward the inner region of the semiconductor wafer W to make the in-plane temperature distribution of the semiconductor wafer W uniform in the preheating stage. Therefore, 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 decrease is measured by the contact thermometer 130 or the radiation thermometer 120, 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, an opaque cylindrical louver 21 and an annular light shielding ring 25 are provided between the halogen heating unit 4 and the chamber 6, and the semiconductor wafer held by the holding unit 7 from the halogen heating unit 4. The optical path of light going to W is adjusted. As described above, when only the louver 21 is provided and preliminary heating is performed by the halogen heating unit 4, the temperature in the region slightly inside the peripheral edge of the semiconductor wafer W tends to be higher. Accordingly, a light shielding ring 25 is provided in addition to the louver 21, and light directed toward a region slightly inside the peripheral edge of the semiconductor wafer W is shielded by the light shielding ring 25, whereby the in-plane temperature distribution of the semiconductor wafer W during the preheating is performed. 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.

Second Embodiment
Next, a second embodiment of the present invention will be described. FIG. 11 is a diagram showing the arrangement of the louvers 21 and the light shielding rings 25 in the second embodiment. In the figure, the same elements as those in the first embodiment are denoted by the same reference numerals. In the first embodiment, the light shielding ring 25 is placed on the ring stage 24 provided on the louver 21. However, in the second embodiment, the lower chamber window facing the halogen heating unit 4 of the chamber 6 is used. A light shielding ring 25 is placed on 64. The remaining configuration and the processing procedure of the semiconductor wafer W in the second embodiment excluding the mounting position of the light shielding ring 25 are the same as those in the first embodiment.

  Similar to the first embodiment, the louver 21 is provided on the louver stage 22 so that the central axis of the cylinder passes through the center of the semiconductor wafer W held by the holding unit 7. The light shielding ring 25 is also provided on the lower chamber window 64 so that the center axis of the annular shape passes through the center of the semiconductor wafer W held by the holding unit 7. The materials and shapes of the louver 21 and the light shielding ring 25 are the same as those in the first embodiment. That is, both the louver 21 and the light shielding ring 25 are made of a material opaque to light emitted from the halogen lamp HL (for example, opaque quartz), and the outer diameter of the light shielding ring 25 is smaller than the inner diameter of the louver 21.

  As shown in FIG. 11, the light emitted from the halogen lamp HL and transmitted through the gap formed between the inner wall surface of the louver 21 and the outer periphery of the light shielding ring 25 is the peripheral portion of the semiconductor wafer W held by the holding portion 7. Is irradiated. As a result, the illuminance at the peripheral edge of the semiconductor wafer W due to light irradiation from the halogen lamp HL becomes relatively high, and the peripheral edge that is likely to cause a temperature drop is strongly heated.

  On the other hand, similarly to the first embodiment, the light shielding ring 25 exists below a region slightly inside the peripheral edge of the semiconductor wafer W held by the holding unit 7. Therefore, as shown in FIG. 11, the light emitted from the halogen lamp HL and traveling toward a region slightly inside the peripheral edge of the semiconductor wafer W is shielded by the light shielding ring 25. As a result, the illuminance in the high temperature region 99 of the semiconductor wafer W that appears when only the louver 21 is installed becomes relatively low, and the heating of the high temperature region 99 is weakened.

  In this way, the combination of the louver 21 and the light shielding ring 25 increases the illuminance at the peripheral portion of the semiconductor wafer W due to light irradiation from the halogen lamp HL, while decreasing the illuminance at the region slightly inside the peripheral portion. As a result, while the peripheral edge of the semiconductor wafer W, which is susceptible to temperature drop, is heated relatively strongly, the heating of the region slightly inside the peripheral edge where the temperature is high only by the louver 21 is relatively weak, The in-plane temperature distribution of the semiconductor wafer W during the preheating can be made uniform.

<Third Embodiment>
Next, a third embodiment of the present invention will be described. FIG. 12 is a diagram showing the arrangement of the louvers 21 and the light shielding rings 25 in the third embodiment. In the figure, the same elements as those in the first embodiment are denoted by the same reference numerals. In the first embodiment, the light shielding ring 25 is placed on the ring stage 24 provided on the louver 21. However, in the third embodiment, the light shielding ring 25 is placed on the louver stage 22 on which the louver 21 is installed. Is also placed. The remaining configuration of the third embodiment and the processing procedure of the semiconductor wafer W except for the mounting position of the light shielding ring 25 are the same as those of the first embodiment.

  Similar to the first embodiment, the louver 21 is provided on the louver stage 22 so that the central axis of the cylinder passes through the center of the semiconductor wafer W held by the holding unit 7. The light shielding ring 25 is also provided on the louver stage 22 so that the center axis of the annular shape passes through the center of the semiconductor wafer W held by the holding unit 7. As shown in FIG. 12, the light shielding ring 25 is placed on a quartz louver stage 22 on which the louver 21 is placed inside a cylindrical louver 21. The materials and shapes of the louver 21 and the light shielding ring 25 are the same as those in the first embodiment. That is, both the louver 21 and the light shielding ring 25 are made of a material opaque to light emitted from the halogen lamp HL (for example, opaque quartz), and the outer diameter of the light shielding ring 25 is smaller than the inner diameter of the louver 21.

  As shown in FIG. 12, the light emitted from the halogen lamp HL and transmitted through the gap formed between the inner wall surface of the louver 21 and the outer periphery of the light shielding ring 25 is the peripheral portion of the semiconductor wafer W held by the holding portion 7. Is irradiated. As a result, the illuminance at the peripheral edge of the semiconductor wafer W due to light irradiation from the halogen lamp HL becomes relatively high, and the peripheral edge that is likely to cause a temperature drop is strongly heated.

  On the other hand, similarly to the first embodiment, the light shielding ring 25 exists below a region slightly inside the peripheral edge of the semiconductor wafer W held by the holding unit 7. Therefore, as shown in FIG. 12, the light emitted from the halogen lamp HL and traveling toward a region slightly inside the peripheral edge of the semiconductor wafer W is shielded by the light shielding ring 25. As a result, the illuminance in the high temperature region 99 of the semiconductor wafer W that appears when only the louver 21 is installed becomes relatively low, and the heating of the high temperature region 99 is weakened.

  In this way, the combination of the louver 21 and the light shielding ring 25 increases the illuminance at the peripheral portion of the semiconductor wafer W due to light irradiation from the halogen lamp HL, while decreasing the illuminance at the region slightly inside the peripheral portion. As a result, while the peripheral edge of the semiconductor wafer W, which is susceptible to temperature drop, is heated relatively strongly, the heating of the region slightly inside the peripheral edge where the temperature is high only by the louver 21 is relatively weak, The in-plane temperature distribution of the semiconductor wafer W during the preheating can be made uniform.

<Fourth embodiment>
Next, a fourth embodiment of the present invention will be described. FIG. 13 is a diagram showing the arrangement of the louvers 28 and 29 and the light shielding ring 25 in the fourth embodiment. In the figure, the same elements as those in the first embodiment are denoted by the same reference numerals. In the first embodiment, the light shielding ring 25 is placed on the ring stage 24 provided on the louver 21. However, in the fourth embodiment, the ring stage 24 sandwiched between the upper and lower louvers 28 and 29. A light shielding ring 25 is placed on the surface. The remaining configuration and the processing procedure of the semiconductor wafer W in the fourth embodiment excluding the mounting position of the light shielding ring 25 are the same as those in the first embodiment.

  In the fourth embodiment, the louver is divided into two upper and lower stages, and an upper louver 29 and a lower louver 28 are provided. The upper louver 29 and the lower louver 28 are each formed of a material that is opaque to light emitted from the halogen lamp HL (for example, opaque quartz), like the louver 21 of the first embodiment. The outer diameter and inner diameter of the upper louver 29 and the lower louver 28 are the same as the louver 21 of the first embodiment. The height of the upper louver 29 and the lower louver 28 may be set appropriately.

  A ring stage 24 is provided so as to be sandwiched between the upper louver 29 and the lower louver 28. In other words, as in the first embodiment, the ring stage 24 is installed at the upper end of the cylindrical lower louver 28, and the same outer diameter and inner diameter are made of the same material as the lower louver 28 on the ring stage 24. A cylindrical upper louver 29 is further provided. A light shielding ring 25 is placed on the upper surface of the ring stage 24.

  The upper louver 29 and the lower louver 28 are stacked so that the central axis of the cylinder passes through the center of the semiconductor wafer W held by the holding unit 7. The light shielding ring 25 is also provided on the ring stage 24 so that the center axis of the annular shape passes through the center of the semiconductor wafer W held by the holding unit 7. The light shielding ring 25 is also formed of a material opaque to the light emitted from the halogen lamp HL (for example, opaque quartz), and the outer diameter of the light shielding ring 25 is smaller than the inner diameters of the upper louver 29 and the lower louver 28.

  As shown in FIG. 13, the light emitted from the halogen lamp HL and transmitted through the gap formed between the inner wall surfaces of the upper louver 29 and the lower louver 28 and the outer periphery of the light shielding ring 25 is a semiconductor held in the holding portion 7. The peripheral edge of the wafer W is irradiated. As a result, the illuminance at the peripheral edge of the semiconductor wafer W due to light irradiation from the halogen lamp HL becomes relatively high, and the peripheral edge that is likely to cause a temperature drop is strongly heated.

  On the other hand, similarly to the first embodiment, the light shielding ring 25 exists below a region slightly inside the peripheral edge of the semiconductor wafer W held by the holding unit 7. Therefore, as shown in FIG. 13, the light emitted from the halogen lamp HL and traveling toward a region slightly inside the peripheral edge of the semiconductor wafer W is shielded by the light shielding ring 25. As a result, the illuminance in the high temperature region 99 of the semiconductor wafer W that appears when only the louver 21 is installed becomes relatively low, and the heating of the high temperature region 99 is weakened.

  In this manner, the combination of the upper louver 29, the lower louver 28, and the light shielding ring 25 increases the illuminance at the peripheral portion of the semiconductor wafer W due to light irradiation from the halogen lamp HL, while the illuminance at the region slightly inside the peripheral portion. Is lowered. As a result, while the peripheral edge of the semiconductor wafer W, which is susceptible to temperature drop, is heated relatively strongly, the heating of the region slightly inside the peripheral edge where the temperature is high only by the louver 21 is relatively weak, The in-plane temperature distribution of the semiconductor wafer W during the preheating can be made 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 each of the above embodiments, the louver 21 and the light shielding ring 25 are formed of opaque quartz in which many fine bubbles are included in quartz glass, but the material of the louver 21 and the light shielding ring 25 is limited to opaque quartz. Is not to be done. For example, the louver 21 and the light shielding ring 25 may be formed of a material that is opaque to light emitted from the halogen lamp HL of the halogen heating unit 4 such as ceramics or metal. The louver 21 and the light shielding ring 25 may be formed of different materials as long as they are opaque to the light emitted from the halogen lamp HL. However, when the light shielding ring 25 is provided inside the chamber 6 as in the second embodiment, it is preferable to form the light shielding ring 25 with opaque quartz that is free from contamination.

  Further, the shape of the light shielding ring 25 is not limited to an annular shape, and the outer periphery thereof may be, for example, a polygon or an ellipse. Even in this case, the light shielding ring 25 is an annular flat plate member. Further, the outer size of the annular light shielding ring 25 is smaller than the size inside the louver 21. Even if such a light shielding ring 25 has an outer size smaller than the inner size of the louver 21, light emitted from the halogen lamp HL is between the inner wall surface of the louver 21 and the outer periphery of the light shielding ring 25. There is a transmissive gap, and the same effects as those of the above embodiments can be obtained.

  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. The technique according to the present invention may be applied to heat treatment of a high dielectric constant gate insulating film (High-k film), bonding between a 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 can be suitably applied to a backside annealing apparatus in which a halogen lamp is disposed below the chamber and light is irradiated from the back surface of the semiconductor wafer to perform heat treatment.

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 Louver 22 Louver stage 24 Ring stage 25 Shading ring 28 Lower louver 29 Upper louver 64 Lower chamber window 65 Heat treatment space FL Flash Lamp HL Halogen lamp W Semiconductor wafer

Claims (6)

A heat treatment apparatus for heating a substrate by irradiating light on a disk-shaped substrate,
A chamber for housing the substrate;
A holding unit for holding the substrate in the chamber;
A light irradiation unit in which a plurality of rod-shaped lamps are arranged in a region facing the main surface wider than the main surface of the substrate held by the holding unit;
A cylindrical first shielding member provided between the light irradiation unit and the holding unit so that a central axis passes through the center of the substrate, and opaque to the light emitted from the light irradiation unit;
A flat plate-shaped second light-shielding member that is provided so that a central axis passes through the center of the substrate between the light irradiation unit and the holding unit, and is opaque to the light emitted from the light irradiation unit;
With
The heat treatment apparatus, wherein an outer size of the second light shielding member is smaller than an inner size of the first light shielding member. The heat treatment apparatus according to claim 1, wherein
The second light shielding member has an annular shape,
An outer diameter of the second light shielding member is smaller than an inner diameter of the first light shielding member. In the heat treatment apparatus according to claim 1 or 2,
The heat treatment apparatus, wherein the second light shielding member is placed on a quartz plate provided on the first light shielding member. In the heat treatment apparatus according to claim 1 or 2,
The heat treatment apparatus, wherein the second light shielding member is placed on a quartz window of the chamber facing the light irradiation unit. In the heat treatment apparatus according to claim 1 or 2,
The heat treatment apparatus, wherein the second light shielding member is placed on a quartz stage on which the first light shielding member is placed inside the first light shielding member. The heat treatment apparatus according to claim 3, wherein
A cylindrical third light-shielding member having the same outer diameter and inner diameter as the first light-shielding member and opaque to the light emitted from the light irradiation unit is further provided on the quartz plate. Heat treatment equipment.

Images