Heat treatment equipment

Abstract

The present invention provides a heat treatment device capable of preventing the discoloration of a gas ring. A gas ring (90) is installed on the side wall of a chamber (6), i.e., the upper part of a chamber side portion (61). The gas ring (90) is formed by overlapping an upper ring (91) and a lower ring (92). The gap between the upper ring (91) and the lower ring (92) becomes a flow path (97) for a processing gas. A blocking portion having a labyrinth structure is formed in the flow path (97). The mass of the lower ring (92) having an inner wall surface (92a) is increased to increase the heat capacity. In addition, the lower ring (92) is installed in a surface contact manner relative to a cooled chamber side portion (61), and the thermal conductivity from the lower ring (92) to the chamber side portion (61) is set to a large value, thereby reducing the amount of heat accumulated in the lower ring (92). As a result, the temperature of the lower ring (92) can be suppressed from rising during heat treatment to prevent the discoloration of the gas ring (90).

Description

Technical Field

[0001] The present invention relates to a heat treatment apparatus that heats a thin plate-shaped precision electronic substrate (hereinafter, simply referred to as a "substrate") such as a semiconductor wafer by irradiating light onto the substrate. Background Art

[0002] In the manufacturing process of semiconductor devices, flash lamp annealing (FLA) for heating semiconductor wafers in a very short time has attracted much attention. Flash lamp annealing is a heat treatment technology that uses a xenon flash lamp (hereinafter referred to as a "flash lamp" to refer to a xenon flash lamp) to irradiate a flash of light onto the surface of a semiconductor wafer, thereby raising the temperature of only the surface of the semiconductor wafer in a very short time (several milliseconds or less).

[0003] The radiation spectrum of the xenon flash lamp is distributed from the ultraviolet region to the near infrared region, and the wavelength is shorter than that of the conventional halogen lamp, and is almost consistent with the basic absorption band of the silicon semiconductor wafer. Therefore, when the xenon flash lamp irradiates the semiconductor wafer with a flash, the transmitted light can at least rapidly heat up the semiconductor wafer. In addition, it is known that if the flash is irradiated in an extremely short time of less than a few milliseconds, it is possible to selectively heat only the vicinity of the surface of the semiconductor wafer.

[0004] Such flash lamp annealing is used for a process that requires heating for an extremely short time, and is typically used, for example, for activation of impurities implanted into a semiconductor wafer. If a flash of light is irradiated from a flash lamp onto the surface of a semiconductor wafer implanted with impurities by ion implantation, the surface of the semiconductor wafer can be heated to the activation temperature in an extremely short time, and only the impurity activation can be performed without deeply diffusing the impurities.

[0005] As such a heat treatment apparatus using a xenon flash lamp, Patent Document 1 discloses an apparatus in which a flash lamp is arranged on the surface side of a semiconductor wafer, and a continuously lit lamp such as a halogen lamp is arranged on the back side, and a desired heat treatment is performed using a combination of these. In the heat treatment apparatus disclosed in Patent Document 1, a semiconductor wafer is preheated to a certain temperature using a halogen lamp, and then the surface of the wafer is heated to a desired treatment temperature using flash irradiation from the flash lamp.

[0006] Patent Document 1 discloses a heat treatment apparatus including a gas ring having a flow path of a labyrinth structure, and a large flow rate of a processing gas is uniformly supplied from the gas ring into a chamber.

[0007] Patent Document 1: Japanese Patent Application Publication No. 2018-195686

[0008] In the flash lamp annealing device, since the surface of the semiconductor wafer is sometimes heated to more than 1000°C, the components in the chamber such as the above-mentioned gas ring are also heated to a certain degree of high temperature. If the preheating temperature using a halogen lamp is about 600°C to 700°C, the temperature rise of the components will not be a problem. However, in recent years, it is often required to process at a higher temperature, and sometimes the preheating temperature exceeds 800°C. If the preheating temperature exceeds 800°C, the gas ring in the chamber is also heated to a high temperature, and there is a problem of discoloration of the surface of the gas ring. If the surface of the gas ring is discolored, the reflectivity of its surface decreases, so there is a concern that the illumination of the flash to the semiconductor wafer during flash irradiation will decrease and the wafer surface will not reach the predetermined processing temperature. Summary of the invention

[0009] In order to solve the above-mentioned problems, the invention of technical solution 1 is a heat treatment device that heats a substrate by irradiating light onto the substrate, and is characterized in that it comprises: a chamber having a cylindrical side wall; a holding portion that holds the substrate in the chamber; a light irradiation portion that irradiates light onto the substrate held by the holding portion; an annular gas ring that is installed on the side wall and guides a processing gas supplied from the outside of the chamber to the inside of the chamber; a cooling mechanism that cools the side wall, the gas ring includes an annular first ring and an annular second ring, a gap between the first ring and the second ring serves as a flow path for the processing gas, the second ring has a cylindrical inner wall surface, the inner wall surface has a diameter smaller than the diameter of the side wall, and at least the second ring is in surface contact with the side wall.

[0010] Furthermore, the invention according to claim 2 is the heat treatment device according to claim 1 , characterized in that the second ring is made of solid material.

[0011] In addition, the invention of Technical Solution 3 is a heat treatment device of the invention of Technical Solution 1, characterized in that a blocking portion with a labyrinth structure is formed in the flow path between the first ring and the second ring, and the blocking portion reduces the flow rate of the processing gas.

[0012] In addition, the invention of Technical Solution 4 is a heat treatment device of the invention of Technical Solution 3, characterized in that the gas ring has a plurality of inlet holes, and the plurality of inlet holes introduce the processing gas supplied from the outside of the chamber via the gas supply port into the blocking part, and the arrangement interval of the plurality of inlet holes becomes wider as the distance from the gas supply port becomes longer.

[0013] Furthermore, the invention of claim 5 is a heat treatment device according to any one of claims 1 to 4, characterized in that the light irradiation unit includes a continuously lighting lamp that irradiates light from below the chamber.

[0014] Furthermore, the invention according to claim 6 is the heat treatment device according to the invention according to claim 5 , characterized in that the light irradiation unit includes a flash lamp that irradiates a flash from above the chamber.

[0015] In addition, the invention of technical solution 7 is a heat treatment device, characterized in that a substrate is heated by irradiating light onto the substrate, and characterized in that it comprises: a chamber having a cylindrical side wall; a holding portion that holds the substrate in the chamber; a light irradiation portion that irradiates light onto the substrate held by the holding portion; an annular gas ring that is installed on the side wall and guides a processing gas supplied from the outside of the chamber to the inside of the chamber; a cooling mechanism that cools the side wall, the gas ring includes an annular first ring and an annular second ring, a gap between the first ring and the second ring serves as a flow path for the processing gas, the second ring has a cylindrical inner wall surface, the inner wall surface has a diameter smaller than the diameter of the side wall, and the heat capacity of the second ring and the thermal conductivity from the second ring to the side wall are set to values ​​such that the inner wall surface of the second ring does not change color due to light irradiation from the light irradiation portion.

[0016] According to the invention of technical solutions 1 to 6, since the second ring of the gas ring having an inner wall surface is in surface contact with the side wall of the cooled chamber, the heat conductivity from the second ring to the side wall is high, the second ring is effectively cooled and the temperature rise of the second ring is suppressed, thereby preventing the gas ring from discoloring.

[0017] In particular, according to the invention of claim 2, the second ring is made of solid material and has a large mass, so that the heat capacity of the second ring becomes large and the temperature rise of the second ring is suppressed, thereby preventing the gas ring from being discolored.

[0018] In particular, according to the invention of claim 3, a blocking portion having a labyrinth structure that reduces the flow rate of the processing gas is formed in the flow path between the first ring and the second ring, so that the processing gas can be uniformly supplied to the chamber.

[0019] In particular, according to the invention of claim 4, since the arrangement intervals of the plurality of introduction holes become wider as the distance from the gas supply port becomes longer, the process gas can be uniformly supplied to the dam portion.

[0020] According to the invention of technical solution 7, since the heat capacity of the second ring having an inner wall surface of the gas ring and the thermal conductivity from the second ring to the side wall of the chamber are set to values ​​so that the inner wall surface of the second ring does not change color due to light irradiation from the light irradiation part, the gas ring can be prevented from changing color. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a longitudinal sectional view showing the structure of the heat treatment apparatus of the present invention.

[0022] Figure 2 It is a perspective view showing the overall appearance of the holding portion.

[0023] Figure 3 This is a top view of the base.

[0024] Figure 4 is a cross-sectional view of the base.

[0025] Figure 5 It is a top view of the transfer mechanism.

[0026] Figure 6 It is a side view of the transfer mechanism.

[0027] Figure 7 It is a top view showing the arrangement of a plurality of halogen lamps.

[0028] Figure 8 It is a perspective view showing a part of the gas ring.

[0029] Fig. 9 It is a perspective view showing the appearance of the upper ring.

[0030] Fig.10 It is a perspective view showing the appearance of the lower ring.

[0031] Fig.11 It is a cross-sectional view of the gas ring installed on the side of the chamber.

[0032] Fig.12 It is a diagram showing the arrangement relationship between the gas supply port and the introduction hole.

[0033] The reference numerals are described as follows:

[0034] 1: Heat treatment device

[0035] 3: Control Department

[0036] 4: Halogen heating unit

[0037] 5: Flash heating unit

[0038] 6: Chamber

[0039] 7: Maintaining part

[0040] 10: Transfer mechanism

[0041] 20: Radiation Thermometer

[0042] 63: Upper chamber window

[0043] 64: Lower chamber window

[0044] 65: Heat treatment space

[0045] 67: Water cooling pipe

[0046] 74: Pedestal

[0047] 81: Gas outlet

[0048] 82: Gas supply port

[0049] 83: Gas supply pipe

[0050] 90: Air Ring

[0051] 91: Upper ring

[0052] 92: Lower ring

[0053] 92a: Inner wall surface

[0054] 93: Lead-in hole

[0055] 97: Flow path

[0056] FL: Flash

[0057] HL: Halogen lamp

[0058] W: semiconductor wafer DETAILED DESCRIPTION

[0059] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0060] Figure 1 It is a longitudinal sectional view showing the structure of the heat treatment apparatus 1 of the present invention. Figure 1 The heat treatment device 1 is a flash lamp annealing device, which heats a disk-shaped semiconductor wafer W as a substrate by irradiating a flash of light to the semiconductor wafer W. The size of the semiconductor wafer W to be processed is not particularly limited, and can be, for example, or (In this embodiment, ). Impurities are implanted into the semiconductor wafer W before being carried into the heat treatment apparatus 1, and the implanted impurities are activated by heating the semiconductor wafer W in the heat treatment apparatus 1. Figure 1 In the following figures, the size and number of each part are exaggerated or simplified as needed to facilitate understanding.

[0061] The heat treatment device 1 has a chamber 6 for accommodating a semiconductor wafer W, a flash heating unit 5 having a plurality of flash lamps FL built therein, and a halogen heating unit 4 having a plurality of halogen lamps HL built therein. The flash heating unit 5 is provided on the upper side of the chamber 6, and the halogen heating unit 4 is provided on the lower side. In addition, the heat treatment device 1 has a holding unit 7 for holding the semiconductor wafer W in a horizontal position inside the chamber 6, and a transfer mechanism 10 for transferring the semiconductor wafer W between the holding unit 7 and the outside of the device. Furthermore, the heat treatment device 1 has a control unit 3, which controls the halogen heating unit 4, the flash heating unit 5, and each action mechanism provided in the chamber 6 to perform heat treatment of the semiconductor wafer W.

[0062] The chamber 6 is formed by installing chamber windows made of quartz on the upper and lower parts of a cylindrical chamber side portion 61. The chamber side portion 61 has a generally cylindrical shape with upper and lower openings, and an upper chamber window 63 is installed at the upper opening to block the upper opening, and a lower chamber window 64 is installed at the lower opening to block the lower opening. The upper chamber window 63 constituting the top of the chamber 6 is a disk-shaped member formed of quartz, and functions as a quartz window that allows the flash emitted from the flash heating unit 5 to pass into the chamber 6. In addition, the lower chamber window 64 constituting the bottom of the chamber 6 is also a disk-shaped member formed of quartz, and functions as a quartz window that allows the light from the halogen heating unit 4 to pass into the chamber 6.

[0063] In addition, an air ring 90 is installed on the upper part of the inner wall surface of the chamber side portion 61, and a reflection ring 69 is installed on the lower part. The air ring 90 and the reflection ring 69 are both formed in a circular ring shape. The inner space of the chamber 6, that is, the space surrounded by the upper chamber window 63, the lower chamber window 64, the chamber side portion 61, the reflection ring 69 and the air ring 90 is defined as a heat treatment space 65.

[0064] By installing the reflection ring 69 and the air ring 90 on the chamber side portion 61, a recessed portion 62 is formed on the inner wall surface of the chamber 6. That is, the recessed portion 62 is formed to be surrounded by the central portion of the inner wall surface of the chamber side portion 61 where the reflection ring 69 and the air ring 90 are not installed, the upper end surface of the reflection ring 69, and the lower end surface of the air ring 90. The recessed portion 62 is formed in a circular ring shape along the horizontal direction on the inner wall surface of the chamber 6, surrounding the holding portion 7 holding the semiconductor wafer W.

[0065] In addition, a transport opening (furnace port) 66 for carrying in and carrying out semiconductor wafers W with respect to the chamber 6 is formed in the chamber side portion 61. The transport opening 66 can be opened and closed by the 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 transport opening 66, the semiconductor wafer W can be carried in and out of the heat treatment space 65 from the transport opening 66 through the recess 62. In addition, if the gate valve 185 closes the transport opening 66, the heat treatment space 65 in the chamber 6 becomes a closed space.

[0066] Furthermore, a through hole 61a is provided through the chamber side portion 61. A radiation thermometer 20 is installed at a portion of the outer wall surface of the chamber side portion 61 where the through hole 61a is provided. The through hole 61a is a cylindrical hole for guiding infrared light radiated from the lower surface of a semiconductor wafer W held by a susceptor 74 described later to the radiation thermometer 20. The through hole 61a is provided obliquely with respect to the horizontal direction so that the axis of the through direction thereof intersects with the main surface of the semiconductor wafer W held by the susceptor 74. A transparent window 21 made of a barium fluoride material is installed at the end of the through hole 61a facing the heat treatment space 65 side, and the transparent window 21 allows infrared light in a wavelength range that can be measured by the radiation thermometer 20 to pass through.

[0067] In addition, a gas ring 90 installed on the upper part of the inner wall of the chamber 6 is formed with a gas ejection port 81 for supplying a processing gas to the heat treatment space 65. The gas ejection port 81 is connected to the gas supply pipe 83 via the internal space of the gas ring 90. The gas supply pipe 83 is connected to the processing gas supply source 85. In addition, a valve 84 is installed in the middle of the path of the gas supply pipe 83. If the valve 84 is opened, the processing gas is transported from the processing gas supply source 85 to the gas ring 90, and the processing gas passing through the internal space of the gas ring 90 is ejected from the gas ejection port 81 to the heat treatment space 65. As the processing gas, for example, an inert gas such as nitrogen (N2), or a reactive gas such as hydrogen (H2), ammonia (NH3), or a mixed gas thereof (nitrogen in this embodiment) can be used. In addition, the structure of the gas ring 90 will be further described later.

[0068] On the other hand, a gas exhaust hole 86 for exhausting the gas in the heat treatment space 65 is formed at the lower part of the inner wall of the chamber 6. The gas exhaust hole 86 is formed at a position lower than the recess 62 and can be set on the reflection ring 69. The gas exhaust hole 86 is connected to the gas exhaust pipe 88 via a buffer space 87 formed in a circular ring shape inside the side wall of the chamber 6. The gas exhaust pipe 88 is connected to the exhaust part 190. In addition, a valve 89 is installed in the middle of the path of the gas exhaust pipe 88. If 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 via the buffer space 87. In addition, the processing gas supply source 85 and the exhaust part 190 can be a mechanism provided in the heat treatment device 1, or a common mechanism of the factory where the heat treatment device 1 is provided.

[0069] A gas exhaust pipe 191 for exhausting the gas in the heat treatment space 65 is connected to the top end 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.

[0070] Figure 2 : is a perspective view showing the overall appearance of the holding part 7. The holding part 7 includes a base ring 71, a connecting part 72, and a base 74. The base ring 71, the connecting part 72, and the base 74 are all formed of quartz. That is, the entire holding part 7 is formed of quartz.

[0071] The base ring 71 is a quartz member in an arc shape with a portion of the ring missing. The missing portion is provided to prevent interference between the transfer arm 11 of the transfer mechanism 10 described later and the base ring 71. The base ring 71 is placed on the bottom surface of the recess 62 and is supported by the wall surface of the chamber 6 (see Figure 1 ). A plurality of connection parts 72 (four in this embodiment) are provided on the upper surface of the base ring 71 along the circumferential direction of the annular shape. The connection parts 72 are also quartz members and are fixed to the base ring 71 by welding.

[0072] The base 74 is supported by four connecting parts 72 provided on the base ring 71 . Figure 3 It is a top view of the base 74 . Figure 4 74. The susceptor 74 includes a holding plate 75, a guide ring 76, and a plurality of substrate support pins 77. The holding plate 75 is a substantially circular flat plate-shaped member formed of quartz. The diameter of the holding plate 75 is larger than the diameter of the semiconductor wafer W. That is, the holding plate 75 has a larger plane size than the semiconductor wafer W.

[0073] A guide ring 76 is provided on the peripheral edge of the upper surface of the holding plate 75. The guide ring 76 is a ring-shaped member having an inner diameter larger than the diameter of the semiconductor wafer W. For example, when the diameter of the semiconductor wafer W is In the case of The inner peripheral surface of the guide ring 76 is formed into a tapered surface that expands upward from the holding plate 75. The guide ring 76 is formed of quartz similarly to the holding plate 75. The guide ring 76 may be welded to the upper surface of the holding plate 75, or may be fixed to the holding plate 75 by a separately processed pin or the like. Alternatively, the holding plate 75 and the guide ring 76 may be processed as an integral member.

[0074] The area on the upper surface of the holding plate 75 that is closer to the inner side than the guide ring 76 is a planar holding surface 75a for holding the semiconductor wafer W. A plurality of substrate support pins 77 are provided on the holding surface 75a of the holding plate 75. In the present embodiment, a total of 12 substrate support pins 77 are provided at intervals of 30° along a circle concentric with the outer circumference of the holding surface 75a (the inner circumference of the guide ring 76). The diameter of the circle on which the 12 substrate support pins 77 are arranged (the distance between the opposing substrate support pins 77) is smaller than the diameter of the semiconductor wafer W. If the diameter of the semiconductor wafer W is Then the diameter of the circle of the substrate support pin 77 is (In this embodiment, Each substrate support pin 77 is formed of quartz. The plurality of substrate support pins 77 may be provided on the upper surface of the holding plate 75 by welding, or may be processed integrally with the holding plate 75.

[0075] return Figure 2 , the four connecting parts 72 erected on the base ring 71 and the peripheral part of the holding plate 75 of the base 74 are fixed by welding. That is, the base 74 and the base ring 71 are fixedly connected by the connecting parts 72. The base ring 71 of the holding part 7 is supported by the wall surface of the chamber 6, so that the holding part 7 is installed in the chamber 6. When the holding part 7 is installed in the chamber 6, the holding plate 75 of the base 74 is in a horizontal posture (a posture in which the normal line is consistent with the vertical direction). That is, the holding surface 75a of the holding plate 75 is in a horizontal plane.

[0076] The semiconductor wafer W carried into the chamber 6 is placed on the pedestal 74 of the holding portion 7 installed in the chamber 6 and held in a horizontal posture. At this time, the semiconductor wafer W is supported by 12 substrate support pins 77 erected on the holding plate 75 and held on the pedestal 74. More precisely, the upper ends of the 12 substrate support pins 77 are in contact with the lower surface of the semiconductor wafer W to support the semiconductor wafer W. Since the heights of the 12 substrate support pins 77 (the distance from the upper ends of the substrate support pins 77 to the holding surface 75a of the holding plate 75) are equal, the semiconductor wafer W can be supported in a horizontal posture by the 12 substrate support pins 77.

[0077] Furthermore, the semiconductor wafer W is supported by the plurality of substrate support pins 77 so as to be spaced apart from the holding surface 75a of the holding plate 75 by a predetermined interval. The thickness of the guide ring 76 is greater than the height of the substrate support pins 77. Therefore, the guide ring 76 prevents the horizontal positional deviation of the semiconductor wafer W supported by the plurality of substrate support pins 77.

[0078] In addition, if Figure 2 and Figure 3 As shown, an opening 78 is formed in the holding plate 75 of the base 74 and penetrates from top to bottom. The opening 78 is provided so that the radiation thermometer 20 receives the radiation light (infrared light) radiated from the lower surface of the semiconductor wafer W. That is, the radiation thermometer 20 receives the light radiated from the lower surface of the semiconductor wafer W through the opening 78 and the transparent window 21 installed in the through hole 61a of the chamber side 61 to measure the temperature of the semiconductor wafer W. In addition, four through holes 79 are penetrated in the holding plate 75 of the base 74, and the lifting pins 12 of the transfer mechanism 10 described later penetrate the through holes 79 to transfer the semiconductor wafer W.

[0079] Figure 5 It is a top view of the transfer mechanism 10 . Figure 61 is a side view of the transfer mechanism 10. The transfer mechanism 10 has two transfer arms 11. The transfer arms 11 are roughly in the shape of an arc along the annular recess 62. Two lifting pins 12 are erected on each transfer arm 11. The transfer arm 11 and the lifting pins 12 are formed of quartz. Each transfer arm 11 can be rotated by a horizontal moving mechanism 13. The horizontal moving mechanism 13 can move a pair of transfer arms 11 in a transfer operation position ( Figure 5 The solid line position) and the retreat position ( Figure 5 As the horizontal moving mechanism 13, each transfer arm 11 can be rotated by using each motor, or a link mechanism can be used to rotate a pair of transfer arms 11 in conjunction with one motor.

[0080] In addition, 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 lifting mechanism 14 raises the pair of transfer arms 11 to the transfer operation position, a total of four lifting pins 12 pass through the through holes 79 (see Figure 2 , 3 ), the upper end of the lifting pin 12 protrudes from the upper surface of the base 74. On the other hand, the lifting mechanism 14 lowers the pair of transfer arms 11 in the transfer action position, so that the lifting pin 12 is pulled out from the through hole 79, and when the horizontal moving mechanism 13 moves the pair of transfer arms 11 in an open manner, each transfer arm 11 moves to the retreat position. The retreat position of the pair of transfer arms 11 is directly above the base ring 71 of the retaining portion 7. Since the base ring 71 is placed on the bottom surface of the recess 62, the retreat position of the transfer arm 11 is on the inner side of the recess 62. In addition, an exhaust mechanism (not shown) is also provided near the location where the drive portion (horizontal moving mechanism 13 and lifting mechanism 14) of the transfer mechanism 10 is provided, and the exhaust mechanism discharges the ambient gas around the drive portion of the transfer mechanism 10 to the outside of the chamber 6.

[0081] return Figure 1 The flash heating unit 5 disposed above the chamber 6 has a light source composed of a plurality of (30 in this embodiment) xenon flash lamps FL and a reflector 52 disposed so as to cover the upper part of the light source, disposed inside a frame 51. In addition, a light radiation window 53 is installed at the bottom of the frame 51 of the flash heating unit 5. The light radiation window 53 constituting the bottom of the flash heating unit 5 is a plate-shaped quartz window formed of quartz. By disposing the flash heating unit 5 above the chamber 6, the light radiation window 53 is opposite to the upper chamber window 63. The flash lamp FL irradiates flash light from above the chamber 6 through the light radiation window 53 and the upper chamber window 63 to the heat treatment space 65.

[0082] The plurality of flash lamps FL are rod-shaped lamps each having a long cylindrical shape, and are arranged in a plane in such a manner that their respective length directions are parallel to each other along the main surface (i.e., along the horizontal direction) of the semiconductor wafer W held by the holding portion 7. Thus, the plane formed by the arrangement of the flash lamps FL is also a horizontal plane. The area in which the plurality of flash lamps FL are arranged is larger than the plane size of the semiconductor wafer W.

[0083] The xenon flash lamp FL has a cylindrical glass tube (discharge tube) in which xenon gas is sealed and an anode and a cathode connected to a capacitor are arranged at both ends, and a trigger electrode is attached to the outer peripheral surface of the glass tube. Since xenon gas is an electrical insulator, even if electric charge is stored in the capacitor, no current flows in the glass tube under normal conditions. However, when a high voltage is applied to the trigger electrode to break the insulation, the electric charge stored in the capacitor flows in the glass tube instantaneously, and light is emitted due to the excitation of xenon atoms or molecules at this 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 milliseconds to 100 milliseconds, so it has the characteristic of being able to irradiate extremely strong light compared to a light source that is continuously lit such as a halogen lamp HL. That is, the flash lamp FL is a pulse light lamp that emits light instantaneously in an extremely short time of less than 1 second. In addition, the light emission time of the flash lamp FL can be adjusted according to the coil constant of the lamp power supply that supplies power to the flash lamp FL.

[0084] Furthermore, the reflector 52 is provided above the plurality of flash lamps FL in a manner covering the entirety of the plurality of flash lamps FL. The basic function of the reflector 52 is to reflect the flash 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 its surface (the surface facing the flash lamp FL side) is roughened by sandblasting.

[0085] The halogen heating unit 4 disposed below the chamber 6 has a plurality of (40 in this embodiment) halogen lamps HL built inside a frame 41. The halogen heating unit 4 is a light irradiation unit that heats the semiconductor wafer W by irradiating light from the bottom of the chamber 6 through the lower chamber window 64 into the heat treatment space 65 using the plurality of halogen lamps HL.

[0086] Figure 7 It is a top view showing the configuration of a plurality of halogen lamps HL. 40 halogen lamps HL are configured in two layers, upper and lower. 20 halogen lamps HL are configured in the upper layer close to the holding portion 7, and 20 halogen lamps HL are configured in the lower layer farther from the holding portion 7 than the upper layer. Each halogen lamp HL is a rod-shaped lamp with a long cylindrical shape. In the upper and lower layers, the 20 halogen lamps HL are arranged so that their respective length directions are parallel to each other along the main surface of the semiconductor wafer W held by the holding portion 7 (i.e., along the horizontal direction). As a result, in the upper and lower layers, the planes formed by the arrangement of the halogen lamps HL are both horizontal planes.

[0087] In addition, if Figure 7 As shown in FIG. 1 , in the upper and lower layers, the arrangement density of the halogen lamps HL in the area opposite to the peripheral portion is higher than that in the area opposite to the central portion of the semiconductor wafer W held by the holding portion 7. That is, in the upper and lower layers, the arrangement pitch of the halogen lamps HL in the peripheral portion is shorter than that in the central portion of the lamp arrangement. Therefore, when heating is performed using the light irradiated by the halogen heating portion 4, a larger amount of light can be irradiated to the peripheral portion of the semiconductor wafer W where the temperature drop is likely to occur.

[0088] In addition, the lamp group consisting of the upper halogen lamps HL and the lamp group consisting of the lower halogen lamps HL are arranged crosswise in a lattice shape, that is, a total of 40 halogen lamps HL are arranged in such a way that the length directions of the 20 halogen lamps HL arranged in the upper layer and the length directions of the 20 halogen lamps HL arranged in the lower layer are orthogonal to each other.

[0089] The halogen lamp HL is a filament-type light source that turns the filament incandescent and emits light by energizing the filament disposed inside a cylindrical glass tube. A gas in which a trace amount of halogen elements (iodine, bromine, etc.) is introduced into an inert gas such as nitrogen or argon is sealed inside the glass tube. By introducing the halogen elements, the breakage of the filament can be suppressed, and the temperature of the filament can be set to a high temperature. Therefore, compared with ordinary incandescent lamps, the halogen lamp HL has the characteristics of a long life and the ability to continuously irradiate strong light. That is, the halogen lamp HL is a continuously lit lamp that emits light continuously for at least 1 second. In addition, because the halogen lamp HL is a rod-shaped lamp and has a long life, by configuring the halogen lamp HL in the horizontal direction, the efficiency of radiating to the semiconductor wafer W above is excellent.

[0090] In addition, a reflector 43 ( Figure 1 ). The reflector 43 reflects the light emitted from the plurality of halogen lamps HL toward the heat treatment space 65 side.

[0091] Next, the structure of the air ring 90 will be described. Figure 8 : is a perspective view showing a part of the gas ring 90. The gas ring 90 attached to the upper part of the inner wall surface of the substantially cylindrical chamber side portion 61 has a circular ring shape. The gas ring 90 is attached so that its center coincides with the center of the chamber side portion 61. That is, the radial direction and the circumferential direction of the gas ring 90 coincide with the radial direction and the circumferential direction of the chamber side portion 61. The gas ring 90 includes an upper ring (first ring) 91 and a lower ring (second ring) 92. Fig. 9 91 is a perspective view showing the appearance of the upper ring 91. Fig.10 1 is a perspective view showing the appearance of the lower ring 92. The upper ring 91 and the lower ring 92 both have an annular shape. The upper ring 91 and the lower ring 92 overlap to form the gas ring 90.

[0092] Fig.11 is a cross-sectional view of the gas ring 90 mounted on the chamber side 61. Fig.11 As shown, the upper ring 91 and the lower ring 92 constituting the gas ring 90 are both mounted on the side wall of the chamber 6, that is, the chamber side portion 61, in a surface contact manner. Therefore, the heat conductivity between the upper ring 91 and the lower ring 92 and the chamber side portion 61 becomes a large value. The chamber side portion 61 is provided with a water cooling pipe 67 in a surrounding manner. The water cooling pipe 67 is supplied with cooling water from a cooling water supply mechanism (not shown). That is, the chamber side portion 61 is a water-cooled wall. By supplying cooling water to the water cooling pipe 67, the upper ring 91 and the lower ring 92 mounted in a surface contact manner with the chamber side portion 61 are also cooled.

[0093] In addition, if Fig.11 As shown in FIG. 1 , the lower ring 92 is provided with an inner wall surface 92a facing the heat treatment space 65. The inner wall surface 92a of the lower ring 92 is formed into a cylindrical shape having a diameter smaller than the diameter of the chamber side portion 61. That is, the inner wall surface 92a of the lower ring 92 extends to the vicinity of the semiconductor wafer W held by the susceptor 74 more than the chamber side portion 61. The diameter of the inner wall surface 92a of the lower ring 92 is, for example, The lower ring 92 having a cylindrical inner wall surface 92 a is a solid material with no space inside, and has a larger mass than the upper ring 91 .

[0094] In the structure in which the upper ring 91 and the lower ring 92 of the annular shape overlap, there is a gap between the upper ring 91 and the lower ring 92. This gap becomes a flow path 97 for guiding the processing gas. A blocking portion having a labyrinth structure is formed in the flow path 97. Specifically, the blocking portion is formed by staggering a plurality of concentric cylindrical walls provided in a downwardly convex manner in the upper ring 91 and a plurality of concentric cylindrical walls provided in an upwardly convex manner in the lower ring 92 at predetermined intervals. With this labyrinth structure blocking portion, the flow path 97 becomes a path curved along the radial direction of the gas ring 90.

[0095] The processing gas transported through the gas supply pipe 83 is supplied from the gas supply port 82 to the flow path 97 of the gas ring 90. The processing gas flowing into the flow path 97 from the gas supply port 82 is introduced into the blocking portion of the flow path 97 through the plurality of introduction holes 93. The processing gas passing through the blocking portion of the flow path 97 is supplied from the gas ejection port 81 provided at the top of the flow path 97 to the heat treatment space 65 in the chamber 6.

[0096] Fig.129 is a diagram showing the arrangement relationship between the gas supply port 82 and the introduction hole 93. The annular gas ring 90 is connected to two gas supply pipes 83 at positions 180° apart from each other. That is, the gas supply port 82 is provided at two locations at an interval of 180°. The gas ring 90 is provided with a plurality of introduction holes 93 of the blocking portion for introducing the processing gas supplied through the two gas supply ports 82 into the flow path 97. Fig.12 As shown, the spacing between the plurality of introduction holes 93 increases as the distance from each gas supply port 82 increases. By arranging the plurality of introduction holes 93 in this manner, the processing gas supplied from the two gas supply ports 82 can be uniformly guided to the flow path 97.

[0097] return Figure 1 The control unit 3 controls the various action mechanisms provided in the heat treatment device 1. The hardware structure of the control unit 3 is the same as that of a general computer. That is, the control unit 3 has a circuit for performing various calculations, i.e., a CPU, a read-only memory for storing basic programs, i.e., a ROM, a freely readable and writable memory for storing various information, i.e., a RAM, and a magnetic disk for storing control software and data. The processing in the heat treatment device 1 is performed by the CPU of the control unit 3 executing a predetermined processing program.

[0098] Next, the processing sequence of the semiconductor wafer W in the heat treatment apparatus 1 is described. Here, the semiconductor wafer W to be processed is a semiconductor substrate to which impurities (ions) are added by ion implantation. The activation of the impurities is performed by flash irradiation heating (annealing) of the heat treatment apparatus 1. The processing sequence of the heat treatment apparatus 1 described below is performed by the control unit 3 controlling each action mechanism of the heat treatment apparatus 1.

[0099] First, the valve 84 for gas supply is opened, and the valves 89 and 192 for exhaust are opened to start supplying and exhausting the chamber 6. When the valve 84 is opened, nitrogen gas as a processing gas is supplied from the processing gas supply source 85 to the gas ring 90, and the nitrogen gas passing through the internal space of the gas ring 90 is ejected from the gas ejection port 81 to the heat treatment space 65. In addition, when the valve 89 is opened, the gas in the chamber 6 is exhausted from the gas exhaust hole 86. As a result, 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.

[0100] In addition, by opening the valve 192, the gas in the chamber 6 is also exhausted from the transfer opening 66. Furthermore, by using an exhaust mechanism (not shown), the ambient gas around the driving part of the transfer mechanism 10 is also exhausted. In addition, during the heat treatment of the semiconductor wafer W in the heat treatment apparatus 1, nitrogen gas is continuously supplied to the heat treatment space 65, and the supply amount is appropriately changed according to the treatment process.

[0101] Next, 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. At this time, there is a concern that the ambient gas outside the apparatus may be brought in with the transfer of the semiconductor wafer W, but since nitrogen gas is continuously supplied to the chamber 6, nitrogen gas flows out from the transfer opening 66, thereby minimizing the external ambient gas brought in.

[0102] The semiconductor wafer W carried in by the transport robot enters the position just above the holding portion 7 and stops. Then, the pair of transfer arms 11 of the transfer mechanism 10 are horizontally moved from the retreat position to the transfer operation position and raised, so that the lift pins 12 pass through the through holes 79 and protrude from the upper surface of the holding plate 75 of the base 74 to receive the semiconductor wafer W. At this time, the lift pins 12 are raised to a position higher than the upper ends of the substrate support pins 77.

[0103] After the semiconductor wafer W is placed on the lifting pins 12, the transport robot withdraws from the heat treatment space 65, and the transport opening 66 is closed by the gate valve 185. Then, the pair of transfer arms 11 descends, so that the semiconductor wafer W is transferred from the transfer mechanism 10 to the base 74 of the holding portion 7 and is held in a horizontal posture from below. The semiconductor wafer W is supported and held on the base 74 by a plurality of substrate support pins 77 erected on the holding plate 75. In addition, the semiconductor wafer W is held on the holding portion 7 and the surface on which the pattern is formed and impurities are injected is used as the upper surface. A predetermined gap is formed between the back side (the main surface on the opposite side to the surface) of the semiconductor wafer W supported by the plurality of substrate support pins 77 and the holding surface 75a of the holding plate 75. The pair of transfer arms 11 that have descended to the bottom of the base 74 are retreated to the retreat position, that is, the inner side of the recess 62 by the horizontal moving mechanism 13.

[0104] After the semiconductor wafer W is held in a horizontal position from below by the base 74 of the holding part 7 formed of quartz, the 40 halogen lamps HL of the halogen heating part 4 are lit together to start preheating (auxiliary heating). The halogen light emitted from the halogen lamp HL passes through the lower chamber window 64 and the base 74 formed of quartz, and irradiates the lower surface of the semiconductor wafer W. By receiving the light irradiation 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 retreats to the inner side of the recess 62, it will not hinder the heating of the halogen lamp HL.

[0105] When preheating is performed using the halogen lamp HL, the temperature of the semiconductor wafer W is measured by the radiation thermometer 20. That is, the radiation thermometer 20 receives infrared light radiated from the lower surface of the semiconductor wafer W held by the susceptor 74 through the opening 78 to measure the temperature of the wafer during heating. The measured temperature of the semiconductor wafer W is transmitted to the control unit 3. The control unit 3 monitors whether the temperature of the semiconductor wafer W, which is heated by the light irradiation from the halogen lamp HL, has reached a predetermined preheating temperature T1, and controls the output of the halogen lamp HL. That is, the control unit 3 feedback controls the output of the halogen lamp HL based on the measured value of the radiation thermometer 20 so that the temperature of the semiconductor wafer W becomes the preheating temperature T1. The preheating temperature T1 is about 200°C to 800°C, preferably about 350°C to 600°C (the preheating temperature is 600°C in this embodiment), at which impurities added to the semiconductor wafer W will not diffuse due to heat.

[0106] After the temperature of the semiconductor wafer W reaches the preheating temperature T1, the control unit 3 temporarily maintains the semiconductor wafer W at the preheating temperature T1. Specifically, when the temperature of the semiconductor wafer W measured by the radiation thermometer 20 reaches the preheating temperature T1, the control unit 3 adjusts the output of the halogen lamp HL to maintain the temperature of the semiconductor wafer W approximately at the preheating temperature T1.

[0107] By preheating with the halogen lamp HL, the temperature of the entire semiconductor wafer W is uniformly raised to the preheating temperature T1. In the preheating stage with the halogen lamp HL, the temperature of the peripheral portion of the semiconductor wafer W, which is easier to dissipate heat, tends to be lower than the temperature of the central portion. However, the arrangement density of the halogen lamp HL in the halogen heating unit 4 is higher in the area facing the peripheral portion than in the area facing the central portion of the substrate W. Therefore, the amount of light irradiated to the peripheral portion of the semiconductor wafer W, which is easier to dissipate heat, increases, so that the in-plane temperature distribution of the semiconductor wafer W in the preheating stage can be made uniform.

[0108] When the temperature of the semiconductor wafer W reaches the preheating temperature T1 and a predetermined time has passed, the flash lamp FL of the flash heating unit 5 flashes the surface of the semiconductor wafer W held by the base 74. At this time, a part of the flash radiated from the flash lamp FL directly irradiates the chamber 6, and the other part is reflected by the reflector 52 and then irradiates the chamber 6. The semiconductor wafer W is flash heated by the above-mentioned flash irradiation.

[0109] Since the flash heating is performed by flash irradiation from the flash lamp FL, the surface temperature of the semiconductor wafer W can be raised in a short time. That is, the flash irradiated from the flash lamp FL is an extremely short strong flash of about 0.1 milliseconds to 100 milliseconds, which is a flash that converts the electrostatic energy previously stored in the capacitor into an extremely short light pulse. Furthermore, the surface temperature of the semiconductor wafer W flash-heated by the flash irradiation from the flash lamp FL instantly rises to a processing temperature T2 of more than 1000° C., and after the impurities injected into the semiconductor wafer W are activated, the surface temperature drops rapidly. In this way, in the heat treatment device 1, since the surface temperature of the semiconductor wafer W can be raised and lowered in an extremely short time, the impurities injected into the semiconductor wafer W can be activated while suppressing the diffusion of impurities by heat. In addition, since the time required for the activation of the impurities is extremely short compared to the time required for the thermal diffusion, the activation can be completed even in a short time of about 0.1 milliseconds to 100 milliseconds when diffusion does not occur.

[0110] After the flash heating treatment is completed, the halogen lamp HL turns off after a predetermined time. As a result, the semiconductor wafer W is rapidly cooled from the preheating temperature T1. The temperature of the semiconductor wafer W being cooled is measured by the radiation thermometer 20, and the measurement result is transmitted to the control unit 3. The control unit 3 monitors whether the temperature of the semiconductor wafer W has been cooled to a predetermined temperature based on the measurement result of the radiation thermometer 20. Then, after the temperature of the semiconductor wafer W drops below the predetermined temperature, the pair of transfer arms 11 of the transfer mechanism 10 are horizontally moved from the retreat position to the transfer action position again and rise, whereby the lifting pins 12 protrude from the upper surface of the base 74 and receive the heat-treated semiconductor wafer W from the base 74. Next, the transport opening 66 closed by the gate valve 185 is opened, and the semiconductor wafer W placed on the lifting pins 12 is moved out by the transport robot outside the device, thereby completing the heating treatment of the semiconductor wafer W in the heat treatment device 1.

[0111] In the present embodiment, nitrogen gas is supplied from a gas ring 90 installed on the upper part of the chamber side portion 61 into the chamber 6. Nitrogen gas supplied from a processing gas supply source 85 via two gas supply pipes 83 is supplied from a gas supply port 82 to a flow path 97 of the gas ring 90. Nitrogen gas flowing from the gas supply port 82 into the flow path 97 is introduced into a blocking portion of the flow path 97 via a plurality of introduction holes 93. The nitrogen gas supplied from the outside of the gas ring 90 is blocked by the blocking portion of the labyrinth structure, and the flow velocity is reduced. The nitrogen gas flows from the outer peripheral side to the inner peripheral side in the radial direction while diffusing in the circumferential direction of the gas ring 90, and is ejected into the chamber 6 from the slit-shaped gas ejection port 81. Thus, even if a large flow rate of nitrogen gas is supplied to the gas ring 90, the nitrogen gas is uniformly ejected from the gas ejection port 81 into the chamber 6.

[0112] In addition, the lower ring 92 of the gas ring 90 has a cylindrical inner wall surface 92a close to the semiconductor wafer W supported by the susceptor 74. Therefore, the inner wall surface 92a of the lower ring 92 receives radiant heat from the semiconductor wafer W heated by the halogen lamp HL. Here, the heat Q accumulated in the lower ring 92 of the gas ring 90 is expressed by the following formula (1).

[0113] Q=Q h -(Q t +Q c +Q r )…(1)

[0114] In formula (1), Q h is the heat received by the lower ring 92 from the surrounding environment of the semiconductor wafer W, etc. t is the amount of heat conducted from the lower ring 92 to the surrounding area, Q c is the heat taken from the lower ring 92 by convection in the chamber 6, Q r is the heat radiated from the lower ring 92. That is, the heat Q received from the lower ring 92 h Subtract the heat released from the lower ring 92 (Q t +Q c +Q r ) is the amount of heat Q accumulated in the lower ring 92.

[0115] On the other hand, the following equation (2) holds true between the amount of heat Q accumulated in the lower ring 92 and the temperature of the lower ring 92 .

[0116] Q=C×(T2-T1)…(2)

[0117] In formula (2), C is the heat capacity of the lower ring 92, T2 is the temperature of the lower ring 92 after heating, and T1 is the temperature of the lower ring 92 before heating. The heat capacity C is represented by the product of the mass m and the specific heat c of the lower ring 92. Here, if the temperature T1 of the lower ring 92 before heating is set to 23°C, the temperature T2 of the lower ring 92 after heating is represented by the following formula (3).

[0118]

[0119] If the temperature T2 of the lower ring 92 after the temperature rise exceeds the critical temperature T d , the inner wall surface 92a of the lower ring 92 changes color. If the inner wall surface 92a of the lower ring 92 changes color, the reflectivity of the inner wall surface 92a decreases, so the amount of flash light emitted from the flash lamp FL and reflected on the inner wall surface 92a decreases. As a result, the illuminance of the flash light irradiated on the semiconductor wafer W during flash irradiation decreases, and there is a concern that the surface temperature of the semiconductor wafer W may not reach the predetermined processing temperature T2.

[0120] Therefore, it is necessary to prevent the temperature T2 of the lower ring 92 heated by the semiconductor wafer W and the like from exceeding the critical temperature T d It is obvious from formula (3) that in order to prevent the temperature T2 from exceeding the critical temperature T d It is necessary to increase the heat capacity C of the lower ring 92 and / or reduce the heat Q accumulated in the lower ring 92.

[0121] The heat capacity C of the lower ring 92 is the product of the mass m and the specific heat c of the lower ring 92. Since the specific heat c is a parameter inherent to the material of the lower ring 92 (stainless steel in this embodiment), it is necessary to increase the mass m of the lower ring 92 in order to increase the heat capacity C. In this embodiment, the lower ring 92 is a solid material ( Fig.11 ), so the mass m of the lower ring 92 is relatively large, so that the heat capacity C can be made to have a large value.

[0122] In addition, among the parameters expressed in equation (1), the amount of heat Q received by the lower ring 92 is h , the heat lost by convection Q c and the radiated heat Q r Therefore, in order to reduce the amount of heat Q accumulated in the lower ring 92, it is necessary to increase the amount of heat Q transferred from the lower ring 92 to the surrounding area. t In this embodiment, the lower ring 92 is installed in a surface contact manner with respect to the chamber side portion 61 to be cooled, so that the heat transfer coefficient from the lower ring 92 to the chamber side portion 61 becomes a large value to effectively cool the lower ring 92. As a result, the heat transfer amount Q transferred from the lower ring 92 to the surrounding area can be reduced to t becomes larger to reduce the heat Q accumulated in the lower ring 92.

[0123] Thus, in the gas ring 90 of the present embodiment, the heat capacity C of the lower ring 92 is increased, and the amount of heat Q stored in the lower ring 92 is reduced, so as to suppress the temperature T2 of the lower ring 92 after the temperature rises. As a result, the temperature T2 of the lower ring 92 can be prevented from exceeding the critical temperature T2 of the color change. d In other words, the heat capacity C of the lower ring 92 and the heat conductivity from the lower ring 92 to the chamber side portion 61 are set to values ​​at which the inner wall surface 92a of the lower ring 92 does not change color when irradiated with light from the halogen lamp HL. As a result, the gas ring 90 can be prevented from changing color.

[0124] The embodiments of the present invention have been described above, but the present invention can be modified in various ways other than the above-mentioned configurations as long as it does not deviate from the purpose thereof. For example, in the above-mentioned embodiment, the blocking portion of the flow path 97 is set as a maze structure in which a plurality of concentric cylindrical walls are assembled, but it is not limited thereto. The blocking portion of the flow path 97 may also be, for example, a structure in which a plurality of columnar members are erected, or a structure in which a plate-like member having a plurality of through holes is provided. Alternatively, the blocking portion of the flow path 97 may include a space for temporarily storing gas, i.e., a buffer. In short, the blocking portion of the flow path 97 may be a structure in which the processing gas supplied via the gas supply pipe 83 can be uniformly supplied to the chamber 6.

[0125] In addition, in the above-mentioned embodiments, the flash heating unit 5 has 30 flash lamps FL, but it is not limited to this, and the number of flash lamps FL can be any number. In addition, the flash lamp FL is not limited to a xenon flash lamp, but can also be a krypton flash lamp. In addition, the number of halogen lamps HL of the halogen heating unit 4 is not limited to 40, but can be any number.

[0126] In addition, in the above embodiment, a filament-type halogen lamp HL is used as a continuous lighting lamp that continuously emits light for more than one second to preheat the semiconductor chip W, but this is not limited to this. Instead of the halogen lamp HL, a discharge-type arc lamp (for example, a xenon arc lamp) can be used as a continuous lighting lamp for preheating.

[0127] Furthermore, the substrate to be processed in the heat treatment apparatus 1 is not limited to a semiconductor wafer, and may be a glass substrate used for a flat panel display such as a liquid crystal display device or a substrate for a solar cell.

Claims

1. A heat treatment device for heating a substrate by irradiating light onto the substrate, characterized in that: have: a chamber having a cylindrical sidewall; a holding portion for holding the substrate in the chamber; a light irradiation unit for irradiating light to the substrate held by the holding unit; a gas ring in a circular shape, mounted on the side wall and directing a processing gas supplied from the outside of the chamber into the inside of the chamber; a cooling mechanism for cooling the side wall, The gas ring includes an upper ring in a circular shape and a lower ring in a circular shape, The gap between the upper ring and the lower ring serves as a flow path for the processing gas. The lower ring has a cylindrical inner wall surface, and the inner wall surface has a diameter smaller than the diameter of the side wall. The inner wall surface of the lower ring is exposed to the heat treatment space in the chamber so as to be transferred with radiant heat from the substrate. At least the lower ring is in surface contact with the side wall.

2. The heat treatment device according to claim 1, characterized in that The lower ring is of solid material.

3. The heat treatment device according to claim 1, characterized in that A blocking portion having a labyrinth structure is formed in the flow path between the upper ring and the lower ring, and the blocking portion reduces the flow rate of the process gas.

4. The heat treatment device according to claim 3, characterized in that: The gas ring includes a plurality of introduction holes for introducing the processing gas supplied from the outside of the chamber through the gas supply port into the blocking portion. The arrangement interval of the plurality of introduction holes increases as the distance from the gas supply port increases.

5. The heat treatment device according to any one of claims 1 to 4, characterized in that: The light irradiation unit includes a continuous lighting lamp configured to irradiate light from below the chamber.

6. The heat treatment device according to claim 5, characterized in that: The light irradiation unit includes a flash lamp that irradiates a flash of light from above the chamber.

7. A heat treatment device, characterized in that: The method for heating a substrate by irradiating light onto the substrate is characterized by comprising: a chamber having a cylindrical sidewall; a holding portion for holding a substrate in the chamber; a light irradiation unit for irradiating light to the substrate held by the holding unit; a gas ring in a circular shape, mounted on the side wall and directing a processing gas supplied from the outside of the chamber into the inside of the chamber; a cooling mechanism for cooling the side wall, The gas ring includes an upper ring in a circular shape and a lower ring in a circular shape, The gap between the upper ring and the lower ring serves as a flow path for the processing gas. The lower ring has a cylindrical inner wall surface, and the inner wall surface has a diameter smaller than the diameter of the side wall. The inner wall of the lower ring is exposed toward the heat treatment space in the chamber to be transferred with radiant heat from the substrate. The heat capacity of the lower ring and the heat conductivity from the lower ring to the side wall are set to values ​​such that the inner wall surface of the lower ring does not change color due to irradiation of light from the light irradiation portion.

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