JP2012074540A - Heat treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat treatment apparatus in which the temperature at the edge of a substrate can be controlled locally and easily, temperature difference between the center part and the vicinity of the edge is reduced, and uniformity of actual temperature of the substrate can be improved easily.SOLUTION: A susceptor 72 installed on the upper surface of a hot plate 71 is divided into a center susceptor 721, a middle susceptor 722, four edge susceptors 723, and four outer periphery susceptors 724 with being separated from each other. The center susceptor 721 facing the most central part of a wafer W to be mounted, and the middle susceptor 722 on the outside thereof are made using quartz as a material. The edge susceptors 723 arranged in an annular region facing the edge of the wafer W, and the outer periphery susceptors 724 on the outside thereof are made of an material which is opaque from ultraviolet ray to infrared ray and has a thermal conductivity larger than that of quartz, e.g. silicon (Si), sintered ceramics (sintered SiC), or a metal (e.g. AlN).

Description

  The present invention relates to a heat treatment apparatus for performing heat treatment on a semiconductor wafer, a glass substrate for a liquid crystal display device or the like (hereinafter simply referred to as “substrate”).

  In the semiconductor device manufacturing process, impurity introduction is an essential 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 into 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 a “flash lamp” means xenon flash lamp). Is a heat treatment apparatus that raises the temperature of only the surface of the film 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 that of a 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. It has also been found that if the irradiation with flash light 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.

  In this type of heat treatment apparatus, when the substrate cannot be heated to the target temperature only by flash irradiation with a flash lamp, the substrate is preliminarily heated. For example, Patent Document 1 discloses that a holding unit that holds a substrate includes a hot plate for auxiliary heating.

JP 2005-277242 A JP-A-6-232138

  In this type of heat treatment apparatus, the temperature in the vicinity of the edge portion tends to be lower than that in the central portion of the substrate, and the entire surface of the substrate cannot be heat treated at a uniform temperature. The cause of this is that heat easily escapes from the edge portion of the substrate by convection or the like. Therefore, the characteristics of the substrate after processing are not uniform, and there is a problem in processing quality. It has been proposed to divide and control the heating area of the hot plate as described in Patent Document 1, or to provide a dedicated heater for heating the edge as described in Patent Document 2, but the heater or the like However, since it takes time to transfer heat until the actual temperature of the substrate is controlled, it is difficult to keep the actual temperature of the substrate uniform.

  The present invention has been made in view of the above points, and provides a heat treatment apparatus capable of easily and locally controlling the temperature of the edge portion of the substrate, and the temperature between the central portion of the substrate and the vicinity of the edge portion. It is an object of the present invention to provide a heat treatment apparatus that can reduce the difference and easily improve the uniformity of the actual temperature of the substrate.

  In order to solve this problem, the invention according to claim 1 is a heat treatment apparatus for heat-treating a substrate, comprising: a mounting table on which the substrate is mounted; and a heat source for heating the mounting table from below. The mounting table is divided and formed into at least two regions, a mounting table center portion facing the center portion of the substrate to be mounted and a mounting table edge portion facing the edge portion of the substrate. It is characterized by.

  According to a second aspect of the present invention, in the heat treatment apparatus according to the first aspect of the present invention, the heat source is provided corresponding to each of the center of the mounting table and the edge of the mounting table.

  The invention according to claim 3 is the heat treatment apparatus according to claim 2, wherein the heat source corresponding to the center of the mounting table and the heat source corresponding to the edge of the mounting table are built in one plate. It is characterized by.

  The invention according to claim 4 is the heat treatment apparatus according to any one of claims 1 to 3, wherein the mounting table edge is formed of a material having a higher thermal conductivity than the mounting table center. It is characterized by.

  According to a fifth aspect of the present invention, in the heat treatment apparatus according to any one of the first to fourth aspects, the upper surface of the mounting table edge is formed flat, and the height is higher than the central portion of the mounting table. It is characterized by being.

  According to a sixth aspect of the present invention, in the heat treatment apparatus according to any one of the first to fourth aspects, the upper surface of the edge of the mounting table is formed as an inclined surface having a lower center side, and more than the central portion of the mounting table. It is characterized by being formed high in height.

  The invention according to claim 7 is the heat treatment apparatus according to any one of claims 1 to 6, wherein the mounting table edge and / or the mounting table center is further divided into a plurality of regions. It is characterized by.

  The invention according to claim 8 is the heat treatment apparatus according to any one of claims 1 to 7, wherein the mounting table edge is formed of an opaque material from ultraviolet to infrared.

  The invention according to claim 9 is the heat treatment apparatus according to any one of claims 1 to 8, further comprising a light heating source that heats the substrate mounted on the mounting table by irradiating light from above. It is characterized by that.

  According to the present invention, the temperature of the edge portion of the substrate can be easily controlled locally.

  Furthermore, according to the invention of claim 2, the temperature of the edge portion of the substrate can be locally controlled with higher accuracy.

  Furthermore, according to the invention of claim 4 and claim 5, the heat conduction to the edge portion of the substrate is good, and the temperature of the edge portion of the substrate can be controlled more effectively locally.

  Furthermore, according to the invention of claim 6, a moderate temperature gradient can be given to the edge portion of the substrate while reducing the temperature difference between the central portion and the vicinity of the edge portion.

  Further, according to the eighth aspect of the invention, it is possible to prevent infrared rays from the heat source from directly passing through the mounting table edge and directly affecting the wafer W.

  Furthermore, according to the invention of claim 9, in combination with the heating from the light source that is likely to cause uneven heating, the uneven heating due to the light irradiation is canceled by finely controlling the temperature distribution of the heating by the lower heat source. It can be reduced and the uniformity of the heating temperature can be improved.

It is a longitudinal cross-sectional view which shows the structure of the heat processing apparatus with which this invention is applied. It is sectional drawing which shows the gas path of the heat processing apparatus of FIG. It is sectional drawing which shows the structure of a holding | maintenance part. It is a top view which shows a hot plate. It is a longitudinal cross-sectional view which shows the structure of the heat processing apparatus of FIG. It is sectional drawing which shows the structure of the modification of a holding | maintenance part.

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

    <1. Overall configuration of heat treatment equipment>

  First, the whole structure of the heat processing apparatus which implements this invention is demonstrated. FIG. 1 is a longitudinal sectional view showing a configuration of a heat treatment apparatus 1 according to the present invention. The heat treatment apparatus 1 is a lamp annealing apparatus that heats a semiconductor wafer W (hereinafter simply referred to as a wafer W) by irradiating light onto a substantially circular semiconductor wafer W having a diameter of 300 mm as a substrate.

  The heat treatment apparatus 1 includes a substantially cylindrical chamber 6 that accommodates a wafer W, and a lamp house 5 that houses a plurality of flash lamps FL. Further, the heat treatment apparatus 1 includes a main controller 3 that controls each operation mechanism provided in the chamber 6 and the lamp house 5 to execute the heat treatment of the wafer W. The heat treatment apparatus 1 is provided with a predetermined wafer supply / storage mechanism (for example, FOUP, not shown) and a transfer robot for transferring the wafer W between the wafer supply / storage mechanism. The wafer W is carried into and out of the chamber 6 by the hand H of the transfer robot.

    <2. Configuration around the chamber>

  The chamber 6 is provided below the lamp house 5 and includes a chamber side portion 63 having a substantially cylindrical inner wall and a chamber bottom portion 62 that covers a lower portion of the chamber side portion 63. Further, a space surrounded by the chamber side 63 and the chamber bottom 62 is defined as a heat treatment space 65. An upper opening 60 is formed above the heat treatment space 65, and a chamber window 61 is attached to the upper opening 60 to close it.

  The chamber window 61 constituting the ceiling portion of the chamber 6 is a disk-shaped member formed of BK7 (borosilicate crown optical glass) which is a kind of optical glass. BK7 transmits visible light and near infrared rays, but is opaque to infrared rays having a wavelength of 3 μm or more. That is, the chamber window 61 formed by BK7 functions as a filter that blocks light having a wavelength of 3 μm or more among the light irradiated from the lamp house 5 into the chamber 6. Accordingly, light emitted from the lamp house 5 enters the heat treatment space 65 with light having a wavelength of less than 3 μm.

  The chamber bottom 62 and the chamber side 63 constituting the main body of the chamber 6 are made of, for example, a metal material having excellent strength and heat resistance, such as stainless steel, and the upper ring on the inner side surface of the chamber side 63 631 is formed of an aluminum (Al) alloy or the like having durability superior to stainless steel against deterioration due to light irradiation.

  Further, in order to maintain the airtightness of the heat treatment space 65, the chamber window 61 and the chamber side portion 63 are sealed by an O-ring. That is, an O-ring is sandwiched between the lower peripheral edge of the chamber window 61 and the chamber side 63 and the clamp ring 90 is brought into contact with the upper peripheral edge of the chamber window 61 so that the clamp ring 90 is attached to the chamber side 63. The chamber window 61 is pressed against the O-ring by screwing.

  The chamber bottom 62 has a plurality (three in this embodiment) for supporting the wafer W from the lower surface (the surface opposite to the side irradiated with the light from the lamp house 5) through the holding portion 7. Book) support pins 70 are provided upright. The support pin 70 is made of, for example, quartz and is fixed from the outside of the chamber 6, so that it can be easily replaced.

  The chamber side portion 63 has a transfer opening 66 for loading and unloading the wafer W by the hand H, and the transfer opening 66 can be opened and closed by a gate valve 185 that rotates about a shaft 662. . A treatment gas (for example, nitrogen (N <SUB> 2 </ SUB>) gas, helium (He) gas, argon (Ar)) is disposed in the heat treatment space 65 at a portion of the chamber side 63 opposite to the transfer opening 66. An introductory path 81 for introducing an inert gas such as gas or oxygen (0 <SUB> 2 </ SUB>) gas is formed, and one end thereof is connected to an air supply mechanism (not shown) via a valve 82. The other end is connected to a gas introduction buffer 83 formed inside the chamber side portion 63. Further, a discharge path 86 for discharging the gas in the heat treatment space 65 is formed in the transfer opening 66, and is connected to an exhaust mechanism (not shown) via a valve 87.

  FIG. 2 is a cross-sectional view of the chamber 6 cut along a horizontal plane at the position of the gas introduction buffer 83. As shown in FIG. 2, the gas introduction buffer 83 is formed over approximately one third of the inner periphery of the chamber side 63 on the opposite side of the transfer opening 66 shown in FIG. Then, the processing gas guided to the gas introduction buffer 83 is supplied into the heat treatment space 65 from the plurality of gas supply holes 84.

  In addition, the heat treatment apparatus 1 includes a substantially disc-shaped holding unit 7 that pre-heats the wafer W held before light irradiation while holding the wafer W in a horizontal position inside the chamber 6, and a holding unit 7. And a holding unit elevating mechanism 4 that elevates and lowers with respect to the chamber bottom 62, which is the bottom surface of the chamber 6. 1 includes a substantially cylindrical shaft 41, a moving plate 42, guide members 43 (three arranged around the shaft 41 in the present embodiment), a fixed plate 44, a ball screw 45, It has a nut 46 and a motor 40. A substantially circular lower opening 64 having a diameter smaller than that of the holding part 7 is formed in the chamber bottom 62, which is the lower part of the chamber 6, and the stainless steel shaft 41 is inserted through the lower opening 64 to hold the holding part. 7 (strictly speaking, the hot plate 71 of the holding unit 7) is connected to the lower surface of the holding unit 7 to support it.

  A nut 46 that is screwed into the ball screw 45 is fixed to the moving plate 42. The moving plate 42 is slidably guided by a guide member 43 that is fixed to the chamber bottom 62 and extends downward, and is movable in the vertical direction. The moving plate 42 is connected to the holding unit 7 through the shaft 41.

  The motor 40 is installed on a fixed plate 44 attached to the lower end of the guide member 43, and is connected to the ball screw 45 via a timing belt 401. When the holding part 7 is raised and lowered by the holding part raising / lowering mechanism 4, the motor 40 as the driving part rotates the ball screw 45 under the control of the main controller 3, and the moving plate 42 to which the nut 46 is fixed follows the guide member 43. Move vertically. As a result, the shaft 41 fixed to the moving plate 42 moves along the vertical direction, and the holding unit 7 connected to the shaft 41 moves the wafer W shown in FIG. 1 and the processing of the wafer W shown in FIG. Move up and down smoothly between positions.

  1, the wafer W is placed on the hand H and transported, and the hand H is slightly lowered above the support pins 70 as shown in FIG. A wafer W is placed. Thereafter, the hand H is retracted in the right direction in the drawing, the gate valve 185 is closed, and the holding unit 7 is moved up to the processing position of the wafer W shown in FIG. Placed.

  On the upper surface of the moving plate 42, a mechanical stopper 451 having a substantially semi-cylindrical shape (a shape obtained by cutting the cylinder in half along the longitudinal direction) is erected so as to follow the ball screw 45. If the upper end of the mechanical stopper 451 hits the end plate 452 provided at the end of the ball screw 45, the moving plate 42 is prevented from rising abnormally. Thereby, the holding part 7 does not rise above a predetermined position below the chamber window 61, and the collision between the holding part 7 and the chamber window 61 is prevented.

  Further, the holding unit elevating mechanism 4 includes a manual elevating unit 49 that manually elevates the holding unit 7 when performing maintenance inside the chamber 6. The manual elevating part 49 has a handle 491 and a rotating shaft 492. By rotating the rotating shaft 492 via the handle 491, the ball screw 45 connected via the timing belt 495 is rotated to raise and lower the holding part 7. It can be carried out.

  A telescopic bellows 47 that surrounds the shaft 41 and extends downward is provided below the chamber bottom 62, and the upper end thereof is connected to the lower surface of the chamber bottom 62. On the other hand, the lower end of the bellows 47 is attached to the bellows lower end plate 471. The bellows lower end plate 471 is attached to the shaft 41 by a hook-like member 411 by screwing. The bellows 47 is contracted when the holding portion 7 is raised relative to the chamber bottom 62 by the holding portion lifting mechanism 4, and the bellows 47 is expanded when the holding portion 7 is lowered. Even when the holding unit 7 moves up and down, the air-tight state in the heat treatment space 65 is maintained by the expansion and contraction of the bellows 47.

    <3. Configuration around holder>

  FIG. 3 is a cross-sectional view showing the configuration of the holding unit 7. As shown in FIG. The holding unit 7 includes a hot plate (heating plate) 71 that preheats the wafer W (so-called assist heating), and a susceptor installed on the upper surface of the hot plate 71 (the surface on the side where the holding unit 7 holds the wafer W). 72 (this is a collective term for a susceptor center 721, a susceptor middle 722, four susceptor edges 723, and four susceptor outer peripheries 724). The susceptor 72 is a table on which the wafer W is placed on the upper surface, and is heated from the lower surface by heat conduction from the hot plate 71 to heat the wafer W. As described above, the shaft 41 that moves up and down the holding unit 7 is connected to the lower surface of the holding unit 7.

  The hot plate 71 includes an upper plate 73 and a lower plate 74 made of stainless steel. Between the upper plate 73 and the lower plate 74, a resistance heating wire 76 such as a nichrome wire as a heat source for heating the hot plate 71 (this is a general term for resistance heating wires 76a, 76b, 76c, 76d described later). Is provided to form a heater, which is filled and sealed with conductive nickel (Ni) wax. The end portions of the upper plate 73 and the lower plate 74 are bonded by brazing.

  FIG. 4 is a plan view showing the upper surface of the holding portion 7, that is, the upper surface of the susceptor 72. The susceptor 72 is disposed in a disc-shaped susceptor center 721 disposed in a region facing the central portion of the wafer W to be placed, and in an annular region facing the edge portion of the wafer W. A susceptor edge 723 having a sector shape obtained by equally dividing the region into four in the circumferential direction, an annular susceptor middle 722 disposed between the susceptor center 721 and the susceptor edge 723, and a susceptor edge 723. The annular region is further divided into a fan-shaped susceptor outer periphery 724 that is equally divided into four in the circumferential direction, and is arranged separately.

  The susceptor center 721, the susceptor middle 722, the four susceptor edges 723, and the four susceptor outer peripheries 724 are detachable and positioned as follows with respect to the flat upper surface of the upper plate 73 constituting the hot plate 71. Attached. That is, two positioning holes (not shown) are formed in the lower surfaces of the susceptor center 721, the susceptor middle 722, the four susceptor end edges 723, and the four susceptor outer peripheries 724, respectively. On the other hand, a pin hole (not shown) is formed in the upper surface of the upper plate 73 corresponding to the positioning hole, and a positioning pin (not shown) is fixed upright in the pin hole.

  Then, each of the susceptor center 721, the susceptor middle 722, the four susceptor end edges 723, and the four susceptor outer peripheries 724 is inserted into the corresponding positioning pins of the upper plate 73 by inserting the positioning holes on the lower surface thereof, The upper plate 73 is attached in a surface-contacted and positioned state so as to be in thermal contact. As a result, heat from the hot plate 71 is placed on the upper surface while being diffused and uniformed by heat conduction in the respective regions of the susceptor center 721, the susceptor middle 722, the four susceptor edges 723, and the four susceptor outer circumferences 724. It reaches the wafer W and heats it, and it can be removed from the upper plate 73 and cleaned during maintenance.

  Further, the susceptor center 721, the susceptor middle 722, the four susceptor edges 723, and the four susceptor outer circumferences 724 are arranged at a slight interval so as not to generate heat conduction in direct contact with each other. Is done. The interval is set so as not to affect the uniformity of the temperature of the wafer W to be mounted, and is specifically about 0.1 mm to 0.5 mm. 3 and 4, the interval is exaggerated. In addition, a pin 75 (details will be described later) for preventing the movement and displacement of the wafer W is attached to the upper surface of the susceptor outer periphery 724 of the susceptor 72 so as to be positioned around the wafer W.

  Among the susceptors 72, a susceptor center 721 that faces the most central portion of the wafer W to be placed, and a susceptor middle 722 that is disposed outside the susceptor center 721 but closer to the center than the susceptor edge 723. Is made of quartz. On the other hand, the susceptor edge 723 disposed in an annular region facing the edge of the wafer W and the susceptor outer periphery 724 disposed further outside the susceptor edge 723 have a thermal conductivity higher than that of quartz. Is made from a material that is opaque from ultraviolet to infrared. Specific examples of materials that have a higher thermal conductivity than quartz and are opaque from ultraviolet to infrared include silicon (Si), sintered ceramics (sintered SiC), and metals (eg, AlN).

  The reason for using an opaque material from ultraviolet rays to infrared rays here is that infrared rays from the hot plate 71 pass through the susceptor edge 723 and the susceptor outer periphery 724 and do not directly affect the wafer W. In other words, since the radiation from the hot plate 71 is not directional, if the material is transparent, the radiation from the center of the hot plate 71 will also strike the edge of the wafer W, causing temperature fluctuations. Can be considered. Therefore, in order to prevent the influence and increase the controllability of temperature, an opaque material from ultraviolet to infrared is used.

  The four susceptor end edges 723 are attached to the upper surface of the flat hot plate 71 so as to form a ring, and the inner diameter of the ring is about 220 mm. The susceptor edge 723 and the susceptor outer periphery 724 are made slightly higher than the susceptor center 721 and the susceptor middle 722, and the height difference between them is 0.2 mm to 1.0 mm. Since the outer diameter of the wafer W is 300 mm, when the wafer W is placed on the center of the susceptor 72, the wafer W is supported in such a manner that the outer peripheral portion having a width of 40 mm is in surface contact with the susceptor edge 723. A distance of 0.2 mm to 1.0 mm, which is a difference in height between the 721 and the susceptor middle 722 and the central portion of the wafer W, is maintained.

  As shown in FIG. 3, the hot plate 71 is composed of one upper plate 73 and one lower plate 74, and the resistance heating wire 76 built in the hot plate 71 is disposed above the hot plate 71. The susceptor center 721, the susceptor middle 722, the four susceptor edges 723, and the four susceptor outer peripheries 724 are individually provided immediately below the susceptor center 721, the susceptor middle 722, and the four susceptor outer periphery 724. That is, the resistance heating wire 76a is directly under the susceptor center 721, the resistance heating wire 76b is directly under the susceptor middle 722, and the four resistance heating wires 76c are directly under the four susceptor edges 723. Four resistance heating wires 76d are provided immediately below the outer periphery 724 of the susceptor. Each of the resistance heating wires 76a, 76b, 76c, and 76d is individually connected to the main controller 3. Further, in each area, a sensor (not shown) provided with a thermocouple for measuring the temperature of the area is individually embedded. This sensor is also connected to the main controller 3 to transmit the measurement result, and the main controller 3 individually heats the resistance heating wires 76a, 76b, 76c, and 76d constituting the heater based on the measurement result of the sensor. By controlling, each region can be controlled to a desired temperature. Further, the hot plate 71 is provided with three through holes 77 through which the support pins 70 are inserted every 120 ° when viewed from the center of the hot plate 71. The support pin 70 is inserted into the through-hole 77 and can pass through the upper surface of the susceptor 72 through the susceptor center 721 and the susceptor middle 722.

  Further, a total of six pins 75 for preventing the movement and displacement of the wafer W are attached to the upper surface of the four outer periphery 724s of the susceptor 72 located on the outermost side of the susceptor 72. The pins 75 are attached by being fitted into attachment holes formed at six equal intervals at positions slightly outside the outer shape of the wafer W placed on the susceptor 72. The pin 75 has a cylindrical shape, and its upper surface is formed into an inclined surface having an angle of about 15 degrees, and the inclined surface is attached so that the center side of the susceptor 72, that is, the side on which the wafer W is placed is lowered. In this type of heat treatment apparatus 1, when the surface of the wafer W is locally expanded or contracted due to a rapid temperature change, a deformation such as a warp of the substrate accompanying the warp is generated or returned. A positional shift of the wafer W with respect to the susceptor 72 may occur. In the heat treatment apparatus 1, even if the wafer W is moved or displaced due to the structure of the pin 75, the displacement of the wafer W occurs when the edge of the wafer W rides on the inclined upper surface of the pin 75. In addition, it is possible to prevent the wafer W from being damaged due to a large stress applied to the wafer W by riding on the inclined upper surface.

  When the hot plate 71 is heated, the resistance heating wire 76a of the heater disposed in each zone is set so that the temperature of each region measured by the sensor 710 becomes a predetermined temperature set in advance. , 76b, 76c, and 76d are controlled by the main controller 3. The temperature control of each zone by the main controller 3 is performed by PID (Proportional Integral Derivative) control. In the hot plate 71, the temperature of each region is continuously measured until the heat treatment of the wafers W (heat treatment of all the wafers W when a plurality of wafers W are continuously processed) is completed. The amount of power supplied to the resistance heating wires 76a, 76b, 76c and 76d of the heaters is individually controlled, that is, the temperature of the heater corresponding to each region is individually controlled, and the temperature of each region is controlled. The set temperature is maintained. The set temperature of each region can be changed by an offset value set individually from the reference temperature.

  The resistance heating wires 76a, 76b, 76c, and 76d of the heaters arranged corresponding to the respective regions are connected to a power supply source (not shown) through a power line passing through the inside of the shaft 41. On the way from the power supply source to each zone, the power lines from the power supply source are arranged so as to be electrically insulated from each other inside a stainless tube filled with an insulator such as magnesia (magnesium oxide). The The interior of the shaft 41 is open to the atmosphere.

    <4. Structure around the lamphouse>

  Next, the lamp house 5 is provided above the holding part 7 in the chamber 6. The lamp house 5 includes a light source including a plurality of (30 in the present embodiment) xenon flash lamps FL and a reflector 52 provided so as to cover the light source inside the housing 51. Composed. A lamp light emission window 53 is mounted on the bottom of the casing 51 of the lamp house 5. The lamp light emission window 53 constituting the bottom part of the lamp house 5 is a plate-like member made of quartz. By installing the lamp house 5 above the chamber 6, the lamp light emission window 53 is opposed to the chamber window 61. The lamp house 5 heats the wafer W by irradiating light from the flash lamp FL through the lamp light emission window 53 and the chamber window 61 to the wafer W held by the holding unit 7 in the chamber 6.

  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 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. Therefore, the plane formed by the arrangement of the flash lamps FL is also a horizontal plane.

  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 light emitted from the plurality of flash lamps FL toward the holding unit 7. The reflector 52 is formed of an aluminum alloy plate, and the surface (the surface facing the flash lamp FL) is roughened by blasting to exhibit a satin pattern. The roughening process is performed when the surface of the reflector 52 is a perfect mirror surface, a regular pattern is generated in the intensity of the reflected light from the plurality of flash lamps FL, and the surface temperature distribution of the wafer W is reduced. This is because the uniformity is lowered.

  The main controller 3 controls the various operation mechanisms provided in the heat treatment apparatus 1. The configuration of the main controller 3 as hardware is the same as that of a general computer. That is, the main controller 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.

    <5. Other configurations>

  In addition to the above configuration, the heat treatment apparatus 1 prevents various temperature increases in the chamber 6 and the lamp house 5 due to thermal energy generated from the flash lamp FL and the hot plate 71 during the heat treatment of the wafer W. It has a structure. For example, water-cooled tubes (not shown) are provided on the chamber side 63 and the chamber bottom 62 of the chamber 6. The lamp house 5 has a gas supply pipe 55 and an exhaust pipe 56 for exhausting heat by forming a gas flow therein and has an air cooling structure (see FIG. 1). Air is also supplied to the gap between the chamber window 61 and the lamp light emission window 53, and the lamp house 5 and the chamber window 61 are cooled.

  As shown in FIGS. 1 and 5, the heat treatment apparatus 1 of the present embodiment includes a quartz probe 18 and a waveform measuring unit 20. The quartz probe 18 is a light guide rod made of quartz, and is provided through the chamber side 63 and the ring 631. The quartz probe 18 is provided such that its longitudinal direction is along the horizontal direction. As shown in FIG. 5, it is preferable that the height position where the quartz probe 18 is installed is slightly above the height position of the wafer W held at the processing position. Further, the base end of the quartz probe 18 passes through the chamber side portion 63 and faces the outside of the chamber 6. The quartz probe 18 may be provided so as to be inclined so that the tip thereof faces the wafer W at the processing position.

    <6. Operation of heat treatment equipment>

  Next, the operation of the heat treatment apparatus 1 having the above configuration will be described. In the heat treatment step, the wafer W to be processed is a semiconductor substrate into which impurities (ions) have been implanted by an ion implantation method, and activation of the implanted impurities is performed by light irradiation heating processing (annealing) by the heat treatment apparatus 1. The In this step, first, as shown in FIG. 1, the hand H of the transfer robot is the processing target with the gate valve 185 opened as the position where the holding unit 7 is lowered (that is, the transfer position of the wafer W). The wafer W is held and conveyed onto the support pins 70 of the holding unit 7 and slightly lowered, and the wafer W is placed on the support pins 70 as shown in FIG. Thereafter, the hand H is retracted to the right in the drawing, the gate valve 185 is closed, the holding unit 7 is raised, and the wafer W is placed at a predetermined position on the susceptor 72 as shown in FIG.

  Next, the wafer W to be processed is heated. Specifically, first, the heater of the hot plate 71 of the holding unit 7 is operated to preheat the wafer W via the susceptor 72 (so-called assist heating). At this time, the main controller 3 individually controls the heating of the resistance heating wires 76a, 76b, 76c, and 76d constituting the heater, and controls each region to a desired preheating temperature. At this time, in consideration of heat radiation from the edge of the wafer W, the main controller 3 uses a resistance heating wire 76c for heating the portion of the susceptor edge 723 that is positioned opposite to the edge of the wafer W. Heating control is performed so that the heat generation amount is obtained.

  The susceptor edge 723 is formed separately from the susceptor center 721 and the susceptor middle 722, and is spaced from and not in direct contact with the susceptor edge 723, so that heat conduction from the susceptor edge 723 to the edge of the wafer W can be prevented. Independent of the temperature of the susceptor center 721 and the susceptor middle 722, local temperature control can be easily performed independently. The susceptor edge 723 has a higher thermal conductivity than the susceptor center 721 and the susceptor middle 722, and is formed of an opaque material from ultraviolet to infrared, so that the heat generated from the heater can be efficiently and quickly transferred to the wafer W. , The control responsiveness is improved, and the local temperature control can be performed more effectively. As a result, the temperature drop at the edge of the wafer W can be reduced or prevented. In the present embodiment, the susceptor edge 723 is in surface contact with the wafer W with a width of 40 mm from the outer periphery of the wafer W, the heat conduction in this region is good, the temperature control in this region can be performed well, and the temperature This is particularly effective for reducing or preventing the decrease.

  When the wafer W has been preheated to a predetermined temperature, the flash lamp FL is then irradiated with intense instantaneous light to rapidly heat the wafer W in a short time. When the heating by the flash lamp FL is finished and the temperature of the wafer W exceeds the peak, the temperature of the wafer W starts to decrease. However, when the temperature of the edge portion of the wafer W is rapidly decreased at this time, the same as described above. The heater can be operated to reduce or prevent the temperature drop at the edge of the wafer W. When these predetermined heat treatments are completed, the holding unit 7 is lowered, the wafer W is supported by the support pins 70, the gate valve 185 is opened, and the hand H carries out the wafer W to be processed.

    <7. Modification>

  FIG. 6 is a cross-sectional view showing a configuration of a modified example of the holding unit 7. In this modification, the upper surface of the susceptor edge 723 that supports the wafer W is formed as an inclined surface 723a up to a height higher than the upper surfaces of the susceptor center 721 and the susceptor middle 722, and the peripheral surface of the wafer W is supported by the inclined surface 723a. As a result, the distance between the susceptor center 721 and the susceptor middle 722 and the central portion of the wafer W is maintained at 0.2 mm to 1.0 mm. The angle formed by the inclined surface 723a and the horizontal plane is preferably 30 degrees or less, and in the embodiment is 15 degrees. By this inclination, the distance between the edge of the wafer W and the susceptor edge 723 is slightly changed between the edge and the inside of the wafer W, and a gentle temperature gradient can be intentionally applied to the temperature of the edge of the wafer W. Note that the surface of the wafer W is locally expanded or contracted due to a rapid temperature change caused by the flash lamp FL, and the warp of the wafer W occurs when the warpage of the substrate is deformed or warped. When the positional deviation with respect to the susceptor 72 occurs, if the angle between the inclined surface 723a and the horizontal plane exceeds 30 degrees, the impact generated between the wafer W and the inclined surface 723a is undesirably increased. If the tilt angle is 30 degrees or less, even if the wafer W is moved or misaligned, the edge of the wafer W rides on the tilted surface 723a, thereby suppressing the occurrence of the misalignment. It is also possible to prevent the wafer W from being damaged due to a large stress applied to the wafer.

  Further, in the above-described embodiment, the heater is provided so as to individually correspond to each region of the susceptor 72 (susceptor center 721, susceptor middle 722, four susceptor edge 723, four susceptor outer periphery 724). Although the individual resistance heating wires 76a, 76b, 76c, and 76d are incorporated, the susceptor 72 and the heater may not necessarily be divided in the same manner. In the above-described embodiment, the resistance heating wires 76a, 76b, 76c, and 76d are incorporated in one hot plate 71 so as to individually correspond to each region of the susceptor 72. Individual hot plates may be provided independently for each region. In that case, it is less affected by heating from adjacent regions, and control with better responsiveness becomes possible.

  In the present invention, the susceptor edge 723 facing the edge of the wafer W is made of a material having a higher thermal conductivity than the susceptor center 721 facing the center of the wafer W to be placed. Therefore, for example, a material having a high thermal conductivity may be used for the susceptor intermediate 722, and another material may be used for the susceptor outer periphery 724 that does not face the edge of the wafer W.

  In the embodiment described above, each region of the susceptor 72 is divided into a disk shape, an annular shape, and a fan shape. However, the susceptor 72 is divided into other shapes such as a small lattice shape. May be.

  Moreover, although the example applied to the lamp annealing apparatus is shown in this embodiment, the present invention is not limited to this and can be used for a laser heating apparatus, a spike annealer, a CVD apparatus, and the like.

1 Heat treatment equipment
3 Main controller
4 Holding mechanism lifting mechanism
6 chambers
7 Holding part
70 Support pin
71 hot plate
72 Susceptor
76, 76a, 76b, 76c, 76d Resistance heating wire
721 center of susceptor
722 Intermediate susceptor
723 Susceptor edge
724 Outside of susceptor FL Flash lamp W Semiconductor wafer

Claims (9)

A heat treatment apparatus for heat-treating a substrate,
A mounting table on which the substrate is mounted on the upper surface;
A heat source for heating the mounting table from below,
The mounting table is divided and formed into at least two regions of a mounting table center portion facing the center portion of the substrate to be mounted and a mounting table edge portion facing the edge portion of the substrate. The heat processing apparatus characterized by the above-mentioned. The heat treatment apparatus according to claim 1, wherein
The said heat source is provided corresponding to each of the said mounting base center part and the said mounting base edge part, The heat processing apparatus characterized by the above-mentioned. The heat treatment apparatus according to claim 2,
A heat treatment apparatus characterized in that the heat source corresponding to the center of the mounting table and the heat source corresponding to the edge of the mounting table are built in one plate. The heat treatment apparatus according to any one of claims 1 to 3,
The mounting table edge portion is formed of a material having a higher thermal conductivity than the mounting table center portion. In the heat treatment apparatus according to any one of claims 1 to 4,
A heat treatment apparatus characterized in that the upper surface of the mounting table edge is formed flat and has a height higher than that of the mounting table center. In the heat treatment apparatus according to any one of claims 1 to 4,
A heat treatment apparatus characterized in that the upper surface of the mounting table edge is formed on an inclined surface having a lower center side and is higher than the central portion of the mounting table. The heat treatment apparatus according to any one of claims 1 to 6,
The heat treatment apparatus characterized in that the mounting table edge and / or the mounting table center is further divided into a plurality of regions. The heat treatment apparatus according to any one of claims 1 to 7,
The heat treatment apparatus characterized in that the mounting table edge is formed of an opaque material from ultraviolet rays to infrared rays. The heat treatment apparatus according to any one of claims 1 to 8,
A heat treatment apparatus, further comprising a photothermal source that heats the substrate placed on the mounting table by irradiating light from above.

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