TW202030802A - Heat treatment method and heat treatment apparatus - Google Patents

Abstract

According to the present invention, 40 halogen lamps are arranged in a rectangular light source region so as to form a grid pattern in two vertical tiers. The halogen lamps are arranged most densely at four corners of the rectangular light source region. A semiconductor wafer is held on a susceptor so that the <100> crystal orientation of the semiconductor wafer coincides with the longitudinal direction of the rod-like halogen lamps. At the time of preliminary heating by means of the halogen lamps, a temperature gradient occurring along the <100> crystal orientation of the semiconductor wafer is smaller than a temperature gradient occurring along the <110> crystal orientation. As a result of the temperature gradient along the <100> crystal orientation, along which warp occurs more easily, becoming smaller than the temperature gradient along the <110> crystal orientation, it is possible to prevent the semiconductor wafer from warping at the time of light irradiation and heating.

Description

Heat treatment method and heat treatment device

The present invention relates to a heat treatment method and a heat treatment apparatus for heating a thin-plate-shaped precision electronic substrate such as a semiconductor wafer (hereinafter referred to as a "substrate") with light.

In the manufacturing process of semiconductor devices, flash annealing (FLA), which heats semiconductor wafers in a very short time, has attracted attention. Flash lamp annealing is a heat treatment technique that uses a xenon flash lamp (hereinafter, referred to as "flash lamp" in abbreviated as xenon flash lamp) to irradiate the flash on the surface of the semiconductor wafer, and only makes the surface of the semiconductor wafer in a very short time ( (A few milliseconds or less) heating up.

The emission spectrum of the xenon flash lamp ranges from the ultraviolet region to the near-infrared region. The wavelength is shorter than that of the previous halogen lamps, and is roughly the same as the basic absorption band of silicon semiconductor wafers. Therefore, when the semiconductor wafer is irradiated with a flash from the xenon flash lamp, the transmitted light is small and the semiconductor wafer can be rapidly heated. In addition, it has also been found that if it is a very short time flash irradiation of a few milliseconds or less, it is possible to selectively increase the temperature of only the vicinity of the surface of the semiconductor wafer.

This flash lamp annealing is used for processes that require a very short time of heating, for example, typically used for activation of impurities implanted into a semiconductor wafer. If the flash is irradiated from the flash lamp to the surface of a semiconductor wafer implanted with impurities by ion implantation, the surface of the semiconductor wafer can be raised to the activation temperature in a very short time, without causing the impurities to diffuse deeply, but only Perform impurity activation.

As a heat treatment apparatus using such a xenon flash lamp, for example, Patent Document 1 discloses that a flash lamp is arranged on the front side of a semiconductor wafer, a halogen lamp is arranged on the back side, and a combination of these and the like performs desired heat treatment. In the heat treatment device disclosed in Patent Document 1, the semiconductor wafer is preheated to a certain temperature by a halogen lamp, and then the surface of the semiconductor wafer is heated to a desired processing temperature by flash irradiation from a flash lamp. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2015-18909

[The problem to be solved by the invention]

In the heat treatment device disclosed in Patent Document 1, a plurality of rod-shaped halogen lamps as a preheating source are arranged in a grid pattern in two upper and lower stages to form a rectangular light source area. When the semiconductor wafer is pre-heated by such a pre-heating source, the in-plane temperature distribution of the semiconductor wafer may also be uneven. In particular, it has been found that the temperature of the peripheral part of the semiconductor wafer facing the four corners of the rectangular light source area densely arranged with the halogen lamp tends to be higher than the surroundings.

If the in-plane temperature distribution of the semiconductor wafer is not uniform during preheating, there is a risk of wafer warping. If wafer warpage occurs during preheating, the semiconductor wafer will also bend during subsequent flash irradiation, so uniform irradiation cannot be performed. Not only does the in-plane temperature distribution of the semiconductor wafer become uneven, but there is also unevenness. Heating may cause the wafer to crack.

The present invention was completed in view of the above-mentioned problems, and its object is to provide a heat treatment method and heat treatment device that can prevent the substrate from lifting during heating. [Technical means to solve the problem]

In order to solve the above-mentioned problems, the invention of claim 1 is a heat treatment method that heats the substrate by irradiating the substrate with light, and is characterized by including: a holding step for holding the substrate on the base in the chamber; and The irradiation step includes irradiating light from the light irradiation portion to the substrate held on the susceptor; in the holding step, the substrate is held on the susceptor in the following direction, that is, in the direction, in the irradiation step When the substrate is irradiated with light, the temperature gradient generated along the <100> direction of the crystal orientation of the substrate is smaller than the temperature gradient generated along the <110> direction.

In addition, the invention of claim 2 is the heat treatment method of the invention of claim 1, characterized in that the light irradiating section includes a plurality of rod-shaped lamps arranged in a grid pattern in two stages in a rectangular light source area, and is held in the above In the process, the substrate is held on the base such that the <100> direction of the crystal orientation of the substrate coincides with the longitudinal direction of the rod lamp.

In addition, the invention of claim 3 is the heat treatment method of the invention of claim 1, wherein the light irradiating section includes a plurality of rod-shaped lamps arranged in parallel in a rectangular light source area, and in the holding step, the The substrate is held on the base in such a way that the <110> direction of the crystal orientation of the substrate coincides with the length direction of the rod-shaped lamp.

In addition, the invention of claim 4, such as the heat treatment method of the invention of claim 2 or claim 3, is characterized in that the rod-shaped lamp is a continuous lighting lamp.

In addition, the invention of claim 5 is the heat treatment method of the invention of claim 3, wherein the rod-shaped lamp is a flash lamp.

In addition, the invention of claim 6 is a heat treatment device that heats the substrate by irradiating the substrate with light, and is characterized by comprising: a chamber for accommodating the substrate; and a susceptor for holding the substrate in the chamber ; A light irradiation section which irradiates light to the substrate held on the base; an alignment section which adjusts the direction of the substrate held on the base; the alignment section irradiates the substrate from the light irradiation section The direction of the substrate is adjusted in such a way that the temperature gradient generated along the <100> direction of the crystal orientation of the substrate during light is smaller than the temperature gradient generated along the <110> direction.

In addition, the invention of claim 7 is the heat treatment apparatus of the invention of claim 6, wherein the light irradiating part includes a plurality of rod-shaped lamps arranged in a grid in two stages in a rectangular light source area, and the alignment part Adjust the direction of the substrate so that the <100> direction of the crystal orientation of the substrate is consistent with the length direction of the rod lamp.

In addition, the invention of claim 8 is the heat treatment device of the invention of claim 6, wherein the light irradiating part includes a plurality of rod-shaped lamps arranged in parallel in a rectangular light source area, and the alignment part is formed by the substrate Adjust the direction of the substrate in such a way that the <110> direction of the crystal orientation is consistent with the length direction of the rod lamp.

Furthermore, the invention of claim 9 is the heat treatment device of the invention of claim 7 or claim 8, characterized in that the rod-shaped lamp is a continuous lighting lamp.

In addition, the invention of claim 10 is the heat treatment device of the invention of claim 8, characterized in that the rod-shaped lamp is a flash lamp. [Effects of Invention]

According to the invention of claim 1 to claim 5, when the substrate is irradiated with light, the temperature gradient generated along the <100> direction of the crystal orientation of the substrate is smaller than the temperature gradient generated along the <110> direction. The susceptor, therefore, has a smaller temperature gradient along the <100> direction that is more likely to warp, which can prevent the substrate from lifting during heating.

According to the invention of technical solution 6 to technical solution 10, the direction of the substrate is adjusted in such a way that the temperature gradient generated along the <100> direction of the crystal orientation of the substrate is smaller than the temperature gradient generated along the <110> direction when the substrate is irradiated with light Therefore, the temperature gradient along the <100> direction which is more likely to produce warpage becomes smaller, which can prevent the substrate from warping during heating.

Hereinafter, the embodiments of the present invention will be described in detail while referring to the drawings.

First, the overall configuration of the heat treatment device of the present invention will be described. FIG. 1 is a top view of a heat treatment device 100 of the present invention, and FIG. 2 is a front view thereof. The heat treatment device 100 is a flash lamp annealing device that irradiates a semiconductor wafer W having a disc shape as a substrate with a flash to heat the semiconductor wafer W. The size of the semiconductor wafer W to be processed is not particularly limited, and is, for example, ϕ300 mm or ϕ450 mm. Furthermore, in FIG. 1 and the subsequent figures, for easy understanding, the size or number of each part is exaggerated or simplified as needed. In addition, in each of FIGS. 1 to 3, an XYZ orthogonal coordinate system in which the Z-axis direction is a vertical direction and the XY plane is a horizontal plane is indicated in order to clarify the directional relationship.

As shown in FIGS. 1 and 2, the heat treatment apparatus 100 includes an indexer part 101 for carrying unprocessed semiconductor wafers W into the apparatus from the outside and carrying out the processed semiconductor wafers W outside the apparatus; Standard part 230, which performs positioning of the unprocessed semiconductor wafer W; 2 cooling parts 130, 140, which cool the semiconductor wafer W after heat treatment; heat treatment part 160, which performs flashing on the semiconductor wafer W Heating processing; and the transfer robot 150, which transfers the semiconductor wafer W to the cooling unit 130, 140 and the heat treatment unit 160. In addition, the heat treatment apparatus 100 includes a control unit 3 that controls the operation mechanism and the transport robot 150 provided in each of the above-mentioned processing units to perform the flash heat treatment of the semiconductor wafer W.

The indexer section 101 is provided with: a load port 110 which arranges and mounts a plurality of carriers C (two in this embodiment); and a transfer robot 120 which takes out the unprocessed semiconductor wafer W from each carrier C and The processed semiconductor wafer W is contained in each carrier C. The carrier C containing the unprocessed semiconductor wafer W is transported by an unmanned transport vehicle (AGV, OHT), etc. and then placed in the load port 110, and the carrier C containing the processed semiconductor wafer W is transported by the unmanned transport vehicle Since the load port 110 is taken away.

In addition, the load port 110 is configured such that the carrier C can move up and down as shown by the arrow CU in FIG. 2 so that the transfer robot 120 can carry out any semiconductor wafer W in and out of the carrier C. Furthermore, as the form of the carrier C, in addition to the FOUP (front opening unified pod) that stores the semiconductor wafer W in a closed space, it can also be SMIF (Standard Mechanical Inter Face) A box or an OC (open cassette) that exposes the contained semiconductor wafer W to external air.

In addition, the transfer robot 120 can perform sliding movement as shown by arrow 120S in FIG. 1, turning movement and lifting movement as shown by arrow 120R. Thereby, the transfer robot 120 performs the transfer of the semiconductor wafer W to and from the two carriers C, and transfers the semiconductor wafer W to the alignment part 230 and the two cooling parts 130 and 140. The transfer of the semiconductor wafer W to the carrier C by the transfer robot 120 is performed by the sliding movement of the hand 121 and the lifting movement of the carrier C. In addition, the transfer of the semiconductor wafer W between the transfer robot 120 and the alignment part 230 or the cooling parts 130 and 140 is performed by the sliding movement of the hand 121 and the lifting motion of the transfer robot 120.

The aligning part 230 is connected to the side of the indexer part 101 along the Y-axis direction and is provided. The alignment part 230 is a processing part that rotates the semiconductor wafer W in a horizontal plane to adjust the direction. The alignment part 230 is provided in the alignment chamber 231 which is an aluminum alloy housing, and is provided with a mechanism for supporting the semiconductor wafer W to rotate in a horizontal position, and optically detecting the recesses formed on the periphery of the semiconductor wafer W Orientation flat (orientation flat) and other mechanisms.

The transfer of the semiconductor wafer W to the alignment part 230 is performed by the transfer robot 120. The self-transfer robot 120 delivers the semiconductor wafer W to the alignment chamber 231 with the center of the wafer at a specific position. In the alignment portion 230, the semiconductor wafer W is rotated around the vertical axis with the center portion of the semiconductor wafer W received from the indexer portion 101 as the center of rotation, and the notch etc. are optically detected, thereby adjusting the semiconductor wafer W direction. The semiconductor wafer W whose orientation adjustment has been completed is taken out from the alignment chamber 231 by the transfer robot 120.

As a transfer space of the semiconductor wafer W by the transfer robot 150, a transfer chamber 170 for accommodating the transfer robot 150 is provided. The processing chamber 6 of the heat treatment part 160, the first cooling chamber 131 of the cooling part 130, and the second cooling chamber 141 of the cooling part 140 are connected to the three sides of the transfer chamber 170.

The heat treatment unit 160 as the main part of the heat treatment apparatus 100 is a substrate processing unit that irradiates the preheated semiconductor wafer W with flash light from the xenon flash lamp FL to perform flash heating treatment. The structure of the heat treatment unit 160 will be described below.

The two cooling units 130 and 140 have substantially the same structure. The cooling parts 130 and 140 are respectively located inside the first cooling chamber 131 and the second cooling chamber 141 which are aluminum alloy shells, and are provided with a metal cooling plate and a quartz plate (both are placed on the upper surface of the cooling plate). Illustration omitted). The temperature of the cooling plate is adjusted to normal temperature (approximately 23°C) by Peltier elements or constant temperature water circulation. The semiconductor wafer W that has been subjected to flash heat treatment by the heat treatment unit 160 is carried into the first cooling chamber 131 or the second cooling chamber 141, placed on the quartz plate, and cooled.

The first cooling chamber 131 and the second cooling chamber 141 are both between the indexer part 101 and the transfer chamber 170 and are connected to both the indexer part 101 and the transfer chamber 170. In the first cooling chamber 131 and the second cooling chamber 141, two openings for carrying the semiconductor wafer W in and out are formed. Among the two openings of the first cooling chamber 131, the opening connected to the indexer portion 101 can be opened and closed by the gate valve 181. On the other hand, the opening of the first cooling chamber 131 connected to the transfer chamber 170 can be opened and closed by the gate valve 183. That is, the first cooling chamber 131 and the indexer portion 101 are connected via the gate valve 181, and the first cooling chamber 131 and the transfer chamber 170 are connected via the gate valve 183.

When the semiconductor wafer W is transferred between the indexer portion 101 and the first cooling chamber 131, the gate valve 181 is opened. In addition, when the semiconductor wafer W is transferred between the first cooling chamber 131 and the transfer chamber 170, the gate valve 183 is opened. When the gate valve 181 and the gate valve 183 are closed, the inside of the first cooling chamber 131 becomes a closed space.

In addition, the opening connected to the indexer part 101 among the two openings of the second cooling chamber 141 can be opened and closed by the gate valve 182. On the other hand, the opening of the second cooling chamber 141 connected to the transfer chamber 170 can be opened and closed by the gate valve 184. That is, the second cooling chamber 141 and the index unit 101 are connected via the gate valve 182, and the second cooling chamber 141 and the transfer chamber 170 are connected via the gate valve 184.

When the semiconductor wafer W is transferred between the indexer portion 101 and the second cooling chamber 141, the gate valve 182 is opened. In addition, when the semiconductor wafer W is transferred between the second cooling chamber 141 and the transfer chamber 170, the gate valve 184 is opened. When the gate valve 182 and the gate valve 184 are closed, the inside of the second cooling chamber 141 becomes a sealed space.

Furthermore, the cooling units 130 and 140 respectively include a gas supply mechanism for supplying clean nitrogen to the first cooling chamber 131 and the second cooling chamber 141, and an exhaust mechanism for exhausting the gas in the chamber. The gas supply mechanism and exhaust mechanism can also switch the flow rate into two stages.

The transfer robot 150 installed in the transfer chamber 170 can rotate as shown by an arrow 150R along the axis in the vertical direction. The transfer robot 150 has two link mechanisms including a plurality of arm segments, and transfer hands 151a and 151b for holding the semiconductor wafer W are respectively provided at the front ends of the two link mechanisms. The conveying hands 151a, 151b are arranged at a predetermined interval from top to bottom, and can be linearly slid and moved in the same horizontal direction independently by a link mechanism. In addition, the transport robot 150 moves the two transport hands 151a and 151b up and down while maintaining a certain distance apart by moving the base on which the two link mechanisms are provided.

When the transfer robot 150 uses the first cooling chamber 131, the second cooling chamber 141, or the processing chamber 6 of the heat treatment unit 160 as the transfer target to transfer (in/out) the semiconductor wafer W, first, use two transfer hands 151a , 151b rotates in a manner opposed to the transfer object, and then (or during the rotation) moves up and down to make any transfer hand at the height of the semiconductor wafer W that is transferred to the transfer object. Then, the transfer hand 151a (151b) is linearly slid and moved in the horizontal direction to transfer the semiconductor wafer W to the transfer target.

The transfer of the semiconductor wafer W between the transfer robot 150 and the transfer robot 120 can be performed via the cooling units 130 and 140. That is, the first cooling chamber 131 of the cooling unit 130 and the second cooling chamber 141 of the cooling unit 140 also function as a passage for transferring the semiconductor wafer W between the transfer robot 150 and the transfer robot 120. Specifically, by transferring one of the transfer robot 150 or the transfer robot 120 to the first cooling chamber 131 or the second cooling chamber 141, the semiconductor wafer W is received by the other to perform the semiconductor wafer W Handover. The transfer robot 150 and the transfer robot 120 constitute a transfer mechanism that transfers the semiconductor wafer W from the carrier C to the heat treatment unit 160.

As described above, the gate valves 181 and 182 are provided between the first cooling chamber 131 and the second cooling chamber 141 and the index part 101, respectively. In addition, gate valves 183 and 184 are respectively provided between the transfer chamber 170 and the first cooling chamber 131 and the second cooling chamber 141. Furthermore, a gate valve 185 is provided between the transfer chamber 170 and the processing chamber 6 of the heat treatment unit 160. When the semiconductor wafer W is transported in the heat treatment apparatus 100, these gate valves are appropriately opened and closed. In addition, nitrogen gas is also supplied from the gas supply unit to the transfer chamber 170 and the alignment chamber 231, and the gas inside the transfer chamber 170 and the alignment chamber 231 is exhausted through the exhaust unit (all omitted).

Next, the structure of the heat treatment unit 160 will be described. 3 is a longitudinal sectional view showing the structure of the heat treatment unit 160. The heat treatment unit 160 includes a processing chamber 6 which houses the semiconductor wafer W for heat treatment; a strobe chamber 5 which houses a plurality of strobe lamps FL; and a halogen lamp chamber 4 which houses a plurality of halogen lamps HL. A strobe chamber 5 is provided on the upper side of the processing chamber 6, and a halogen lamp chamber 4 is provided on the lower side. In addition, the heat treatment unit 160 is provided inside the processing chamber 6 with a holding unit 7 that holds the semiconductor wafer W in a horizontal posture; and a transfer mechanism 10 that carries the semiconductor wafer between the holding unit 7 and the transfer robot 150 The handover of W.

The processing chamber 6 is constructed by installing a chamber window made of quartz on the upper and lower sides of the cylindrical chamber side 61. The chamber side portion 61 has a substantially cylindrical shape with upper and lower openings. An upper chamber window 63 is attached to the upper opening to close, and a lower chamber window 64 is attached to the lower opening to close. The upper side chamber window 63 constituting the top of the processing chamber 6 is a circular plate-shaped member formed of quartz, and functions as a quartz window that allows flash light emitted from the flash lamp FL to pass into the processing chamber 6. In addition, the lower chamber window 64 at the bottom of the processing chamber 6 is also a disc-shaped member formed of quartz, and functions as a quartz window for transmitting light from the halogen lamp HL into the processing chamber 6.

In addition, a reflection ring 68 is attached to the upper part of the wall surface inside the chamber side portion 61, and a reflection ring 69 is attached to the lower part. Both the reflection rings 68 and 69 are formed in an annular shape. The reflection ring 68 on the upper side is installed by being inserted from the upper side of the chamber side 61. On the other hand, the reflection ring 69 on the lower side is installed by being inserted from the lower side of the chamber side portion 61 and fixed with screws (not shown). That is, the reflection rings 68 and 69 are both detachably attached to the chamber side portion 61. The space inside the processing chamber 6, that is, the space surrounded by the upper chamber window 63, the lower chamber window 64, the chamber side 61, and the reflection rings 68 and 69 is defined as the heat treatment space 65.

By installing the reflection rings 68 and 69 on the side part 61 of the chamber, a recess 62 is formed on the inner wall surface of the processing chamber 6. That is, a recess 62 surrounded by the inner wall surface of the chamber side 61 where the reflection rings 68 and 69 are not attached, the lower end surface of the reflection ring 68, and the upper end surface of the reflection ring 69 are formed. The recess 62 is formed in an annular shape along the horizontal direction on the inner wall surface of the processing chamber 6 and surrounds the holding part 7 holding the semiconductor wafer W. The chamber side 61 and the reflection rings 68 and 69 are formed of a metal material (for example, stainless steel) excellent in strength and heat resistance.

In addition, a transfer opening (furnace opening) 66 for carrying in and out of the semiconductor wafer W with respect to the processing chamber 6 is formed in the chamber side 61. The conveyance opening 66 can be opened and closed by the gate valve 185. The conveyance opening 66 is in communication and connection with 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 transported into the heat treatment space 65 from the transport opening 66 through the recess 62, and the semiconductor wafer W can be transported out of the heat treatment space 65. In addition, if the gate valve 185 closes the conveyance opening 66, the heat treatment space 65 in the processing chamber 6 becomes a closed space.

In addition, a gas supply hole 81 for supplying the processing gas to the heat treatment space 65 is formed on the upper part of the inner wall of the processing chamber 6. The gas supply hole 81 is formed at a position higher than the recess 62, and may also be provided at the reflection ring 68. The gas supply hole 81 communicates with the gas supply pipe 83 via a buffer space 82 formed in the side wall of the processing chamber 6 in an annular shape. The gas supply pipe 83 is connected to a processing gas supply source 85. In addition, a valve 84 is inserted in the middle of the path of the gas supply pipe 83. When the valve 84 is opened, the processing gas is sent from the processing gas supply source 85 to the buffer space 82. The processing gas flowing into the buffer space 82 flows so as to diffuse in the buffer space 82 whose fluid resistance is smaller than that of the gas supply hole 81, and is supplied into the heat treatment space 65 from the gas supply hole 81. As the processing gas, an inert gas such as nitrogen (N ₂ ) or a reactive gas such as hydrogen (H ₂ ) or ammonia (NH ₃ ) (in this embodiment, nitrogen) can be used.

On the other hand, at the lower part of the inner wall of the processing chamber 6 is formed a gas exhaust hole 86 for exhausting the gas in the heat treatment space 65. The gas exhaust hole 86 is formed at a lower position than the recess 62, and may also be provided at the reflection ring 69. The gas exhaust hole 86 is connected to the gas exhaust pipe 88 through a buffer space 87 formed in the side wall of the processing chamber 6 in an annular shape. The gas exhaust pipe 88 is connected to the exhaust mechanism 190. In addition, a valve 89 is inserted in the middle of the path of the gas exhaust pipe 88. When the valve 89 is opened, the gas in the heat treatment space 65 is discharged from the gas exhaust hole 86 to the gas exhaust pipe 88 through the buffer space 87. Furthermore, the gas supply hole 81 and the gas exhaust hole 86 may be provided in plural along the circumferential direction of the processing chamber 6, or may be slit-shaped. In addition, the processing gas supply source 85 and the exhaust mechanism 190 may be a mechanism installed in the heat treatment device 100, or may be a facility in a factory where the heat treatment device 100 is installed.

In addition, a gas exhaust pipe 191 for exhausting the gas in the heat treatment space 65 is also connected to the front end of the conveying opening 66. The gas exhaust pipe 191 is connected to the exhaust mechanism 190 via a valve 192. By opening the valve 192, the gas in the processing chamber 6 is exhausted through the conveying opening 66.

FIG. 4 is a perspective view showing the overall appearance of the holding portion 7. The holding portion 7 includes a base ring 71, a connecting portion 72, and a base 74. The base ring 71, the connecting portion 72, and the base 74 are all formed of quartz. That is, the entire holding portion 7 is formed of quartz.

The abutment ring 71 is a circular arc-shaped quartz member obtained by cutting a part from the circular ring shape. The cut-out portion is provided to prevent interference between the transfer arm 11 of the transfer mechanism 10 described below and the base ring 71. The abutment ring 71 is placed on the bottom surface of the recess 62 and supported by the wall surface of the processing chamber 6 (refer to FIG. 3). On the upper surface of the abutment ring 71, a plurality of connecting portions 72 (four in this embodiment) are erected along the circumferential direction of the ring shape. The connecting portion 72 is also a quartz member, and is fixed to the abutment ring 71 by welding.

The base 74 is supported by four connecting parts 72 provided on the base ring 71. FIG. 5 is a top view of the base 74. 6 is a cross-sectional view of the base 74. The base 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 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 plane size larger than that of the semiconductor wafer W.

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 ϕ300 mm, the inner diameter of the guide ring 76 is ϕ320 mm. The inner circumference of the guide ring 76 is formed as a tapered surface that widens upward from the holding plate 75. The guide ring 76 is formed of the same quartz as 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 using separately processed pins or the like. Alternatively, the holding plate 75 and the guide ring 76 may be processed as an integral member.

A region on the upper surface of the holding plate 75 that is more inside than the guide ring 76 is set as a planar holding surface 75a for holding the semiconductor wafer W. A plurality of substrate support pins 77 are erected on the holding surface 75a of the holding plate 75. In this embodiment, a total of 12 board support pins 77 are erected at intervals of 30° along the circumference of the outer circumference of the holding surface 75a (the inner circumference of the guide ring 76) which is concentric. The diameter of the circle with 12 substrate support pins 77 (the distance between the opposed substrate support pins 77) is smaller than the diameter of the semiconductor wafer W. If the diameter of the semiconductor wafer W is ϕ300 mm, the diameter of the circle is ϕ270 mm～ϕ280 mm (ϕ270 mm 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.

Returning to FIG. 4, the four connecting portions 72 erected on the base ring 71 and the peripheral edge portions of the holding plate 75 of the base 74 are fixedly connected by welding. That is, the base 74 and the base ring 71 are fixedly connected by the connecting portion 72. By supporting the abutment ring 71 of the holding portion 7 by the wall surface of the processing chamber 6, the holding portion 7 is installed in the processing chamber 6. In the state where the holding portion 7 is installed in the processing chamber 6, the holding plate 75 of the base 74 is in a horizontal posture (posture in which the normal line coincides with the vertical direction). That is, the holding surface 75a of the holding plate 75 becomes a horizontal surface.

The semiconductor wafer W carried in the processing chamber 6 is placed and held in a horizontal posture on the susceptor 74 mounted on the holding portion 7 of the processing chamber 6. At this time, the semiconductor wafer W is supported by the 12 substrate support pins 77 erected on the holding plate 75 and held on the base 74. More strictly speaking, the upper ends of the 12 substrate support pins 77 contact the lower surface of the semiconductor wafer W to support the semiconductor wafer W. Since the height of the 12 substrate support pins 77 (the distance from the upper end of the substrate support pins 77 to the holding surface 75a of the holding plate 75) is uniform, the 12 substrate support pins 77 can be used to support the semiconductor wafer W in a horizontal posture.

In addition, the semiconductor wafer W is supported by a plurality of substrate support pins 77 at a predetermined interval from the holding surface 75 a of the holding plate 75. Compared with the height of the substrate support pin 77, the thickness of the guide ring 76 is greater. Therefore, the horizontal position deviation of the semiconductor wafer W supported by the plurality of substrate supporting pins 77 is prevented by the guide ring 76.

In addition, as shown in FIGS. 4 and 5, the holding plate 75 of the base 74 has an opening 78 penetrating vertically. The opening 78 is provided for the radiation thermometer 20 (refer to FIG. 3) to receive the radiation light (infrared light) emitted from the lower surface of the semiconductor wafer W held by the susceptor 74. That is, the radiation thermometer 20 receives the 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 semiconductor wafer W. Furthermore, the holding plate 75 of the susceptor 74 is provided with four through holes 79 through which the jack-up pins 12 of the transfer mechanism 10 described below pass through to transfer the semiconductor wafer W.

FIG. 7 is a top view of the transfer mechanism 10. 8 is a side view of the transfer mechanism 10. The transfer mechanism 10 includes two transfer arms 11. The transfer arm 11 is formed in an arc shape like a recess 62 along a substantially circular ring. Two jacking pins 12 are erected on each transfer arm 11. Each transfer arm 11 can be rotated by a horizontal movement mechanism 13. The horizontal movement mechanism 13 moves the pair of transfer arms 11 to the transfer operation position (the solid line position in FIG. 7) for transferring the semiconductor wafer W with respect to the holding portion 7, and the semiconductor wafer held in the holding portion 7 W moves horizontally between the retreat positions that do not overlap when viewed from above (the two-point chain position in Figure 7). The transfer action position is below the base 74, and the retracted position is outside the base 74. The horizontal movement mechanism 13 may be a mechanism that uses individual motors to rotate each transfer arm 11 separately, or may be a mechanism that uses a link mechanism to rotate a pair of transfer arms 11 in conjunction with one motor.

In addition, the pair of transfer arms 11 are moved up and down together with the horizontal movement mechanism 13 by the lifting mechanism 14. If the lifting mechanism 14 raises the pair of transfer arms 11 at the transfer operation position, a total of four jacking pins 12 pass through the through holes 79 (see FIGS. 4 and 5) provided in the base 74, and the jacking pins 12 The upper end protrudes from the upper surface of the base 74. On the other hand, if the lifting mechanism 14 lowers the pair of transfer arms 11 at the transfer operation position to pull the jacking pin 12 out from the through hole 79, and the horizontal movement mechanism 13 opens the pair of transfer arms 11 Move, each transfer arm 11 moves to the retracted position. The retreat position of the pair of transfer arms 11 is directly above the base ring 71 of the holding portion 7. Since the abutment ring 71 is placed on the bottom surface of the recess 62, the retracted position of the transfer arm 11 is inside the recess 62. Furthermore, an exhaust mechanism (not shown) is also provided near the location where the driving part (horizontal movement mechanism 13 and the lifting mechanism 14) of the transfer mechanism 10 is provided, and the structure is configured such that the vicinity of the driving part of the transfer mechanism 10 The gas is discharged to the outside of the chamber 6.

Returning to FIG. 3, the flash lamp chamber 5 disposed above the processing chamber 6 is provided with a light source including a plurality of xenon flash lamps FL (30 in this embodiment) inside the housing 51, and a light source covering the light source The reflector 52 is arranged on the upper side. In addition, a light emission window 53 is installed at the bottom of the housing 51 of the strobe room 5. The light emission window 53 constituting the bottom of the strobe chamber 5 is a plate-shaped quartz window formed of quartz. By setting the strobe chamber 5 above the processing chamber 6, the light emission window 53 and the upper chamber window 63 are opposed to each other. The flash lamp FL irradiates the heat treatment space 65 with flashes from above the processing chamber 6 through the light emission window 53 and the upper chamber window 63.

The plurality of flash lamps FL are rod lamps each having a long cylindrical shape, and are arranged in such a manner that their length directions are parallel to each other along the main surface of the semiconductor wafer W held by the holding portion 7 (ie, along the horizontal direction) Plane arrangement. Therefore, the plane formed by the arrangement of the flash lamps FL is also a horizontal plane.

The xenon flash lamp FL is equipped with: a rod-shaped glass tube (discharge tube), which is filled with xenon gas and is equipped with anode and cathode connected to a capacitor at both ends; and a trigger electrode attached to the glass tube The outer circumference. Since xenon gas is an electrical insulator, even if electric charge is accumulated in the capacitor, electricity will not flow into the glass tube under normal conditions. However, when a high voltage is applied to the trigger electrode and the insulation is broken, the electricity stored in the capacitor instantly flows into the glass tube, and light is emitted by the excitation of xenon atoms or molecules at this time. In this type of xenon flash lamp FL, the electrostatic energy pre-stored in the capacitor is converted into an extremely short light pulse of 0.1 millisecond to 100 milliseconds. Therefore, compared with the continuous lighting light source such as the halogen lamp HL, it has extremely strong illumination Features of light. That is, the flash lamp FL is a pulsed light that emits instantaneously in a very short time of less than 1 second. Furthermore, the light-emitting time of the flash lamp FL can be adjusted according to the coil constant of the lamp power supply for the flash lamp FL.

In addition, the reflector 52 is arranged to cover the whole of the plurality of flash lamps FL. The basic function of the reflector 52 is to reflect the flashes emitted from the plurality of flash lamps FL to the heat treatment space 65 side. The reflector 52 is formed of an aluminum alloy plate, and the surface (the surface facing the flash FL) is roughened by sandblasting.

The halogen lamp chamber 4 provided below the processing chamber 6 contains a plurality of (40 in this embodiment) halogen lamps HL inside the housing 41. The plurality of halogen lamps HL irradiate light to the heat treatment space 65 through the lower chamber window 64 from below the treatment chamber 6.

Fig. 9 is a plan view showing the arrangement of a plurality of halogen lamps HL. In this embodiment, 20 halogen lamps HL are arranged in the upper and lower sections of the rectangular light source area. Each halogen lamp HL is a rod-shaped lamp having a long cylindrical shape. The upper and lower sections are each with 20 halogen lamps HL arranged in such a manner that their respective longitudinal directions are parallel to each other along the main surface of the semiconductor wafer W held by the holding portion 7 (ie, along the horizontal direction). Therefore, the plane formed by the arrangement of halogen lamps HL in the upper and lower sections is a horizontal plane.

In addition, as shown in FIG. 9, the upper and lower stages are both the halogen lamp in the area opposed to the central portion of the semiconductor wafer W held in the holding portion 7, and the area opposed to the peripheral portion of the semiconductor wafer W The distribution density of HL is higher. That is, both the upper and lower sections are arranged at a shorter pitch than the central part of the lamp arrangement, and the halogen lamps HL at the peripheral part are arranged at a shorter distance. Therefore, it is possible to irradiate a larger amount of light to the peripheral portion of the semiconductor wafer W that is likely to cause a temperature drop when heated by light irradiation from the halogen heating portion 4.

In addition, the lamp group including the halogen lamp HL of the upper stage and the lamp group including the halogen lamp HL of the lower stage are arranged in a grid-like cross. That is, a total of 40 halogen lamps HL are arranged such that the longitudinal direction of each halogen lamp HL in the upper stage is orthogonal to the longitudinal direction of each halogen lamp HL in the lower stage.

The halogen lamp HL is a filament light source in which the filament is incandescent and emits light by energizing the filament arranged inside the glass tube. Inside the glass tube, a gas obtained by introducing a small amount of halogen elements (iodine, bromine, etc.) into an inert gas such as nitrogen or argon is enclosed. By introducing halogen elements, the breakage of the filament can be suppressed, and the temperature of the filament can be set to high temperature. Therefore, the halogen lamp HL has the characteristics of a longer lifespan than a normal incandescent bulb and that it can continuously emit strong light. That is, the halogen lamp HL is a continuous lighting lamp that continuously emits light for at least 1 second. In addition, since the halogen lamp HL is a rod-shaped lamp, it has a long life. By arranging the halogen lamp HL in the horizontal direction, the radiation efficiency of the upward semiconductor wafer W becomes excellent.

Moreover, in the housing 41 of the halogen lamp chamber 4, a reflector 43 is also provided under the two-stage halogen lamp HL (FIG. 3). The reflector 43 reflects the light emitted from the plurality of halogen lamps HL to the heat treatment space 65 side.

In addition to the above structure, the heat treatment unit 160 also has various cooling structures to prevent the halogen lamp chamber 4, flash lamp chamber 5, and processing chamber from being caused by the heat generated from the halogen lamp HL and flash lamp FL during the heat treatment of the semiconductor wafer W The temperature of chamber 6 rises excessively. For example, a water cooling pipe (not shown) is provided on the wall of the processing chamber 6. In addition, the halogen lamp chamber 4 and the strobe chamber 5 are provided with an air cooling structure in which a gas flow is formed and heat is discharged. In addition, air is also supplied to the gap between the upper chamber window 63 and the light emission window 53 to cool the strobe chamber 5 and the upper chamber window 63.

The control unit 3 controls the above-mentioned various operating mechanisms provided in the heat treatment apparatus 100. The hardware configuration of the control unit 3 is the same as that of a normal computer. That is, the control unit 3 has a CPU (Central Processing Unit) as a circuit for performing various arithmetic processing, a ROM (Read Only Memory) as a read-only memory for storing basic programs, and a memory RAM (Random Access Memory) for free reading and writing of various information and disks 35 for pre-memorizing control software or data. The processing in the heat treatment apparatus 100 is performed by the CPU of the control unit 3 executing a specific processing program. Furthermore, in FIG. 1, the control unit 3 is shown in the index unit 101, but it is not limited to this, and the control unit 3 can be arranged at any position in the heat treatment apparatus 100.

Next, the processing operation of the heat treatment apparatus 100 of the present invention will be described. Here, after describing the processing operation of the normal semiconductor wafer W as a product, the direction adjustment of the semiconductor wafer W will be described. The semiconductor wafer W to be processed is a semiconductor substrate to which impurities (ions) are added by an ion implantation method. The activation of this impurity is performed by flash irradiation heat treatment (annealing) using the heat treatment device 100.

First, the unprocessed semiconductor wafer W injected with impurities is placed in the load port of the indexer part 101 in a state where a plurality of pieces are accommodated in the carrier C. Then, the transfer robot 120 takes out the unprocessed semiconductor wafers W from the carrier C one by one and carries them into the alignment chamber 231 of the alignment part 230. In the alignment chamber 231, the direction of the semiconductor wafer W is adjusted by rotating the semiconductor wafer W around the vertical axis in the horizontal plane with its center as the center of rotation, and optically detecting the notch. The direction adjustment of the semiconductor wafer W at this time will be described in detail below.

Next, the transfer robot 120 of the indexer part 101 takes out the semiconductor wafer W whose orientation has been adjusted from the alignment chamber 231 and carries it into the first cooling chamber 131 of the cooling part 130 or the second cooling chamber 141 of the cooling part 140. The unprocessed semiconductor wafer W carried in the first cooling chamber 131 or the second cooling chamber 141 is carried out to the transfer chamber 170 by the transfer robot 150. When the unprocessed semiconductor wafer W is transferred from the indexer part 101 to the transfer chamber 170 through the first cooling chamber 131 or the second cooling chamber 141, the first cooling chamber 131 and the second cooling chamber 141 serve as semiconductors The path for the transfer of wafer W functions.

The transfer robot 150 that takes out the semiconductor wafer W rotates toward the heat treatment unit 160. Then, the gate valve 185 opens the gap between the processing chamber 6 and the transfer chamber 170, and the transfer robot 150 transfers the unprocessed semiconductor wafer W into the processing chamber 6. At this time, when the previously heat-treated semiconductor wafer W exists in the processing chamber 6, the heat-treated semiconductor wafer W is taken out by one of the transfer hands 151a and 151b, and then the unprocessed semiconductor wafer The wafer W is carried into the processing chamber 6 and wafer replacement is performed. Then, the gate valve 185 closes the space between the processing chamber 6 and the transfer chamber 170.

The semiconductor wafer W carried in the processing chamber 6 is preheated by the halogen lamp HL, and then subjected to flash heating treatment by flash irradiation from the flash lamp FL. The activation of the impurities injected into the semiconductor wafer W is performed by the flash heating process.

After the flash heating process is completed, the gate valve 185 opens the processing chamber 6 and the transfer chamber 170 again, and the transfer robot 150 transports the semiconductor wafer W after the flash heating process from the processing chamber 6 to the transfer chamber 170. The transfer robot 150 that takes out the semiconductor wafer W rotates from the processing chamber 6 toward the first cooling chamber 131 or the second cooling chamber 141. In addition, the gate valve 185 closes the space between the processing chamber 6 and the transfer chamber 170.

Then, the transfer robot 150 transfers the heat-processed semiconductor wafer W into the first cooling chamber 131 of the cooling part 130 or the second cooling chamber 141 of the cooling part 140. At this time, when the semiconductor wafer W passes through the first cooling chamber 131 before the heat treatment, it is still carried into the first cooling chamber 131 after the heat treatment, and passes through the second cooling chamber 141 before the heat treatment. In this case, it is still carried into the second cooling chamber 141 after the heat treatment. In the first cooling chamber 131 or the second cooling chamber 141, a cooling process of the semiconductor wafer W after the flash heating process is performed. Since the temperature of the entire semiconductor wafer W at the time of removal from the processing chamber 6 of the heat treatment section 160 is relatively high, the semiconductor wafer W is cooled to normal temperature in the first cooling chamber 131 or the second cooling chamber 141 nearby.

After a specific cooling processing time has elapsed, the transfer robot 120 unloads the cooled semiconductor wafer W from the first cooling chamber 131 or the second cooling chamber 141 and returns it to the carrier C. If a certain number of processed semiconductor wafers W are contained in a carrier C, the carrier C is carried out from the load port 110 of the indexer section 101.

The description of the heat treatment in the heat treatment part 160 is continued. Before the semiconductor wafer W is loaded into the processing chamber 6, the valve 84 for air supply is opened, and the valves 89 and 192 for exhaust are opened to start the exhaust of the processing chamber 6. When the valve 84 is opened, nitrogen gas is supplied to the heat treatment space 65 from the gas supply hole 81. Furthermore, if the valve 89 is opened, the gas in the processing chamber 6 is discharged from the gas exhaust hole 86. Thereby, the nitrogen gas supplied from the upper part of the heat treatment space 65 in the processing chamber 6 flows downward and is discharged from the lower part of the heat treatment space 65.

Furthermore, by opening the valve 192, the gas in the processing chamber 6 is also discharged from the conveyance opening 66. Furthermore, the gas around the driving part of the transfer mechanism 10 is also exhausted by the exhaust mechanism (not shown). Furthermore, during the heat treatment of the semiconductor wafer W in the heat treatment unit 160, nitrogen gas is continuously supplied to the heat treatment space 65, and the supply amount thereof is appropriately changed according to the treatment process.

Then, the gate valve 185 is opened and the transfer opening 66 is opened, and the semiconductor wafer W to be processed is carried into the heat treatment space 65 in the processing chamber 6 through the transfer opening 66 by the transfer robot 150. The transfer robot 150 causes the transfer hand 151a (or the transfer hand 151b) holding the unprocessed semiconductor wafer W to enter the position directly above the holding portion 7 and stop. Then, by one of the transfer mechanism 10, the transfer arm 11 moves horizontally from the retracted position to the transfer action position and rises, so that the jacking pin 12 is moved from the upper surface of the holding plate 75 of the base 74 through the through hole 79 The semiconductor wafer W is protruded and received. At this time, the jack-up pin 12 rises above the upper end of the board support pin 77.

After the unprocessed semiconductor wafer W is placed on the jacking pin 12, the transfer robot 150 retracts the transfer hand 151a from the heat treatment space 65, and the transfer opening 66 is closed by the gate valve 185. Then, when the pair of transfer arms 11 descend, the self-transfer mechanism 10 of the semiconductor wafer W is transferred to the base 74 of the holding portion 7 and held from below in a horizontal posture. The semiconductor wafer W is supported by a plurality of substrate support pins 77 erected on the holding plate 75 and held on the base 74. In addition, the semiconductor wafer W is held by the holding portion 7 with the patterned and impurity-implanted surface as the upper surface. A specific interval is formed between the back surface (the main surface on the opposite side to the front 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 fallen below the base 74 is retracted to the retracted position, that is, inside the recess 62 by the horizontal movement mechanism 13.

After the semiconductor wafer W is held from below in a horizontal posture by the susceptor 74 of the holding portion 7, the 40 halogen lamps HL are all turned on to start preheating (auxiliary heating). The halogen light emitted from the halogen lamp HL is irradiated from the lower surface of the semiconductor wafer W through the lower chamber window 64 and the base 74 formed of quartz. By receiving light from the halogen lamp HL, the semiconductor wafer W is preheated and the temperature rises. Furthermore, since the transfer arm 11 of the transfer mechanism 10 has retracted to the inner side of the recess 62, the heating by the halogen lamp HL is not hindered.

When the halogen lamp HL is used for preheating, the temperature of the semiconductor wafer W is measured with the radiation thermometer 20. That is, the radiation thermometer 20 receives infrared light radiated from the lower surface of the semiconductor wafer W held on the susceptor 74 through the opening 78 to measure the temperature of the wafer during the temperature increase. 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 raised by the light from the halogen lamp HL has reached a specific 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 set to a temperature at which there is no fear that the impurities added to the semiconductor wafer W will diffuse due to heat, that is, about 600°C to 800°C (700°C in this embodiment).

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, at the time point when the temperature of the semiconductor wafer W measured by the radiation thermometer 20 reaches the pre-heating temperature T1, the control unit 3 adjusts the output of the halogen lamp HL to maintain the temperature of the semiconductor wafer W at approximately the pre-heating temperature T1 .

After the temperature of the semiconductor wafer W reaches the preheating temperature T1, the flash lamp FL irradiates the surface of the semiconductor wafer W with a flash of light at a time point when a specific time has passed. At this time, a part of the flash light emitted from the flash lamp FL is directly directed into the processing chamber 6, and the other part is temporarily reflected by the reflector 52 and then directed into the processing chamber 6. The semiconductor wafer W is irradiated by the flash light. The flash heating.

The flash heating is performed by flash light irradiation from the flash lamp FL, so that the surface temperature of the semiconductor wafer W can be increased in a short time. That is, the flash light irradiated from the flash lamp FL converts the electrostatic energy previously stored in the capacitor into an extremely short light pulse with an irradiation time of approximately 0.1 millisecond or more and 100 milliseconds or less. Moreover, the surface temperature of the semiconductor wafer W heated by the flash light by the flash light from the flash lamp FL instantly rises to the processing temperature T2 of 1000° C. or more. After the impurities injected into the semiconductor wafer W are activated, the surface temperature drops rapidly. In this way, the surface temperature of the semiconductor wafer W can be raised and lowered in a very short time during the flash heating, so the impurity injected into the semiconductor wafer W can be inhibited from being thermally diffused, and the impurity can be activated. Furthermore, since the time required for the activation of impurities is extremely short compared to the time required for thermal diffusion, the activation is completed even in a short time of about 0.1 milliseconds to 100 milliseconds without diffusion.

After the flash heating treatment is completed, the halogen lamp HL is extinguished after a certain time has passed. Thereby, the semiconductor wafer W is rapidly cooled from the preheating temperature T1. The temperature of the semiconductor wafer W during cooling 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 dropped to a specific temperature based on the measurement result of the radiation thermometer 20. Then, after the temperature of the semiconductor wafer W drops below a certain level, the transfer arm 11 of one of the transfer mechanisms 10 moves horizontally from the retracted position to the transfer action position and rises again, whereby the jacking pin 12 is lifted from the base The upper surface of the seat 74 protrudes to receive the heat-treated semiconductor wafer W from the seat 74. Then, the transfer opening 66 closed by the gate valve 185 is opened, and the processed semiconductor wafer W placed on the ejector pin 12 is carried out by the transfer hand 151b (or the transfer hand 151a) of the transfer robot 150. The transfer robot 150 moves the transfer hand 151b into a position directly below the semiconductor wafer W lifted by the lift pin 12 and stops. Then, the pair of transfer arms 11 descend, and the semiconductor wafer W heated by the flash is delivered and placed on the transfer hand 151b. Then, the transfer robot 150 withdraws the transfer hand 151b from the processing chamber 6 to unload the processed semiconductor wafer W.

Next, the direction adjustment of the semiconductor wafer W will be described. Typically, the semiconductor wafer W described above as a product is a thin plate-shaped substrate formed by thinly slicing a cylindrical single crystal silicon ingot (for example, if it is ϕ 300 mm, the thickness is 0.775 mm). Therefore, the semiconductor wafer W to be processed in this embodiment is also formed of single crystal silicon. In addition, the semiconductor wafer W is sliced along the specific crystal orientation of the silicon ingot. Typically, three types of wafers with plane orientations of (100) plane, (110) plane, and (111) plane are used, but wafers with (100) plane orientation are used at most. In this embodiment, the semiconductor wafer W to be processed is also a single crystal silicon wafer with a (100) plane orientation.

FIG. 10 is a diagram showing a semiconductor wafer W of single crystal silicon with a plane orientation of (100). A ϕ300 mm silicon semiconductor wafer W is engraved with grooves 201 for indicating crystal orientation. The groove 201 is arranged in a manner indicating the direction of <110>. In other words, the diameter 202 in the direction shown by the groove 201 is the diameter along the <110> direction. In addition, the diameter 202 (diameter extending in the horizontal direction in FIG. 10) that is 90° to the direction shown by the groove 201 is also the diameter along the <110> direction. On the other hand, the two diameters 203 that are 45° from the direction shown by the groove 201 are the diameters along the <100> direction.

FIG. 11 is a diagram showing the positional relationship between the semiconductor wafer W held on the susceptor 74 in the processing chamber 6 and the halogen lamp HL. In FIG. 11, for convenience of illustration, each halogen lamp HL is represented by a broken line. As described above, in this embodiment, in the rectangular light source area, 40 halogen lamps HL are arranged in a grid pattern across two upper and lower stages. The upper and lower sections are arranged at a shorter interval than the halogen lamps HL at the central part and peripheral part of the lamp arrangement. Therefore, among the four corners of the rectangular light source area, the halogen lamps HL are most densely arranged.

When the semiconductor wafer W is pre-heated by 40 halogen lamps HL, it is easy to heat the part of the semiconductor wafer W opposite to the four corners of the rectangular light source area densely arranged with halogen lamps HL. . As a result, during the preheating, it was found that the part of the semiconductor wafer W opposite to the four corners of the rectangular light source region tends to become a high-temperature hot spot HS than other parts. Therefore, in the surface of the semiconductor wafer W during preheating, a larger diameter will be generated along the diameter direction connecting the hot spot HS (the diameter direction from the upper left to the lower right in FIG. 11 and the diameter from the upper right to the lower left). The temperature gradient. On the other hand, the temperature gradient in the diameter direction that does not pass through the hot spot HS (the longitudinal diameter direction and the lateral diameter direction in FIG. 11) is relatively small.

During preheating, the direction in which the semiconductor wafer W warps due to the uneven temperature distribution depends on the crystal orientation, and the <100> direction is more likely to warp than the <110> direction. That is, when a temperature gradient is generated in the <100> direction in the plane of the semiconductor wafer W, the temperature gradient is more likely to occur in the <110> direction, and wafer warping is likely to occur. Therefore, in this embodiment, the semiconductor wafer W is held on the susceptor in such a manner that the <100> direction of the crystal orientation of the semiconductor wafer W indicated by the arrow AR11 coincides with the longitudinal direction of the rod-shaped halogen lamp HL 74. Specifically, the alignment part 230 adjusts the semiconductor wafer W in such a manner that the diameter 203 along the <100> direction of the crystal orientation of the semiconductor wafer W coincides with the longitudinal direction of the halogen lamp HL and holds the semiconductor wafer W on the base 74. The direction of wafer W. Furthermore, during the process of transferring the semiconductor wafer W from the alignment chamber 231 to the processing chamber 6, the directional relationship between the semiconductor wafer W and the halogen lamp HL is maintained.

As shown in FIG. 11, if the semiconductor wafer W is held on the susceptor 74 in such a way that the diameter 203 along the <100> direction of the crystal orientation of the semiconductor wafer W coincides with the length direction of the halogen lamp HL, the preheating When the diameter 202 along the <110> direction shown by the groove 201 passes through the hot spot HS, a relatively large temperature gradient is generated along the <110> direction. On the other hand, along the <100> direction of the crystal orientation of the semiconductor wafer W, no large temperature gradient is generated.

Therefore, the temperature gradient generated along the <100> direction of the crystal orientation of the semiconductor wafer W during preheating by the halogen lamp HL is smaller than the temperature gradient generated along the <110> direction. That is, the temperature gradient along the <100> direction where warpage is more likely to occur is smaller than the temperature gradient along the <110> direction. As a result, it is possible to prevent the semiconductor wafer W from lifting when light is irradiated from the halogen lamp HL during preheating. Thereby, during flash heating after pre-heating, the flat semiconductor wafer W is irradiated with flash from the flash lamp FL, which can perform uniform flash heating and prevent the semiconductor wafer W from cracking due to uneven heating. .

The embodiments of the present invention have been described above, but the present invention can be variously modified in addition to the above as long as it does not deviate from the gist. For example, in the above-mentioned embodiment, a plurality of halogen lamps HL are arranged in a grid pattern in two upper and lower stages, but a plurality of halogen lamps HL may be arranged in one stage in parallel with each other. FIG. 12 is a diagram showing another example of the positional relationship between the semiconductor wafer W and the halogen lamp HL. In FIG. 12, for the convenience of illustration, each halogen lamp HL is shown by a broken line.

In the example shown in FIG. 12, a plurality of halogen lamps HL are arranged in parallel in one segment in a rectangular light source area. When preheating the semiconductor wafer W with the halogen lamp HL arranged in this way, it was confirmed that the both ends of the diameter along the arrangement direction of the halogen lamp HL tend to have a tendency to become a cold spot CS that is lower than other parts. . Therefore, during the preheating, in the surface of the semiconductor wafer W, a large temperature gradient is generated along the diameter direction (the horizontal diameter direction in FIG. 12) connecting the cold spots CS. On the other hand, the temperature gradient in the direction that does not pass through the diameter of the cold spot CS is relatively small.

Therefore, in the example shown in FIG. 12, the semiconductor wafer W is held in such a manner that the <110> direction of the crystal orientation of the semiconductor wafer W indicated by the arrow AR12 coincides with the length direction of the rod-shaped halogen lamp HL于base 74. Specifically, the semiconductor wafer W is held on the susceptor 74 by the diameter 202 along the <110> direction of the crystal orientation of the semiconductor wafer W shown in the recess 201 and the length direction of the halogen lamp HL. The alignment part 230 adjusts the direction of the semiconductor wafer W. Thereby, the semiconductor wafer W is held on the susceptor 74 such that the diameter 203 along the <100> direction of the crystal orientation of the semiconductor wafer W and the longitudinal direction of the halogen lamp HL are at 45°.

As shown in Figure 12, if the <110> direction of the crystal orientation of the semiconductor wafer W is consistent with the length direction of the rod-shaped halogen lamp HL, that is, the <100> direction is 45° to the length direction of the halogen lamp HL Holding the semiconductor wafer W on the susceptor 74 generates a relatively large temperature gradient along the diameter 202 in the <110> direction passing through the cold spot CS. On the other hand, along the <100> direction of the crystal orientation of the semiconductor wafer W, no large temperature gradient is generated.

Therefore, as in the above embodiment, the temperature gradient generated along the <100> direction of the crystal orientation of the semiconductor wafer W during preheating by the halogen lamp HL is smaller than the temperature gradient generated along the <110> direction. As a result, it is possible to prevent the semiconductor wafer W from lifting when light is irradiated from the halogen lamp HL during preheating.

In addition, the arrangement of the halogen lamps HL may be other than those shown in FIGS. 11 and 12. In this case, if the temperature gradient generated along the <100> direction of the crystal orientation of the semiconductor wafer W during preheating with the halogen lamp HL is smaller than the temperature gradient generated along the <110> direction, the semiconductor The wafer W is held on the base 74 to prevent the semiconductor wafer W from lifting.

Furthermore, in the above embodiment, the direction of the arrangement of the semiconductor wafer W with respect to the halogen lamp HL is adjusted, but the direction of the arrangement of the semiconductor wafer W with respect to the flash lamp FL can also be adjusted. Although the irradiation time is extremely short, the flash lamp FL is also a rod-shaped lamp. By arranging a plurality of flash lamps FL as shown in Figure 11 or Figure 12 for flash heating, the same temperature distribution as the above is generated in the surface of the semiconductor wafer W Uneven parts (hot spot HS or cold spot CS). Therefore, by adjusting the direction of the semiconductor wafer W to hold the susceptor 74 in the same manner as described above, it is possible to prevent the semiconductor wafer W from lifting during the flash heating from the flash lamp FL.

In short, the technology of the present invention only needs to be that when the semiconductor wafer W is irradiated with light, the temperature gradient generated along the <100> direction of the crystal orientation of the semiconductor wafer W is smaller than the temperature gradient generated along the <110> direction. The semiconductor wafer W may be held by the susceptor 74. Since the temperature gradient along the <100> direction where warpage is more likely to occur is smaller than the temperature gradient along the <110> direction, the semiconductor wafer W can be prevented from being warped during light irradiation and heating.

In addition, in the above-mentioned embodiment, the strobe room 5 includes 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, and may be a krypton flash lamp. In addition, the number of halogen lamps HL included in the halogen lamp chamber 4 is not limited to 40, and can be any number.

In addition, in the above-mentioned embodiment, the halogen lamp HL of the filament method is used as a continuous lighting lamp that emits light continuously for more than 1 second to preheat the semiconductor wafer W, but it is not limited to this, and may be substituted for the halogen lamp HL. A discharge type arc lamp (for example, a xenon arc lamp) is used as a continuous lighting lamp for preheating. In this case, the temperature gradient generated along the <100> direction of the crystal orientation of the semiconductor wafer W when light is irradiated from the arc lamp is smaller than the temperature gradient generated along the <110> direction. Keep on the base 74. Thereby, it is possible to prevent the semiconductor wafer W from lifting during heating by the arc lamp.

In addition, the substrate to be processed by the heat treatment apparatus 100 is not limited to a semiconductor wafer, and may be a glass substrate or a substrate for solar cells used in flat panel displays such as liquid crystal display devices.

3: Control Department 4: Halogen lamp room 5: Flash room 6: Processing chamber 7: Holding part 10: Transfer mechanism 11: Transfer arm 12: jack pin 13: Horizontal movement mechanism 14: Lifting mechanism 20: Radiation thermometer 35: Disk 41: Shell 43: reflector 51: Shell 52: reflector 53: light emission window 61: Chamber side 62: recess 63: Upper chamber window 64: Lower chamber window 65: Heat treatment space 66: Transport opening 71: Abutment Ring 72: Connection 74: Pedestal 75: hold the board 75a: keep face 76: Guide ring 77: substrate support pin 78: opening 79: Through hole 81: Gas supply hole 82: buffer space 83: Gas supply pipe 84: Valve 85: Process gas supply 86: Gas vent 87: buffer space 88: Gas exhaust pipe 89: Valve 100: Heat treatment device 101: Indexer Department 110: load port 120: Handover Robot 120R: Arrow 120S: Arrow 121: hand 130: Cooling part 131: 1st cooling chamber 140: Cooling part 141: 2nd cooling chamber 150: transport robot 150R: Arrow 151a: Transporter 151b: Transporter 160: Heat Treatment Department 170: transfer chamber 181: Gate Valve 182: Gate Valve 183: Gate Valve 184: Gate Valve 185: gate valve 190: Exhaust Department 191: Gas exhaust pipe 192: Valve 201: Groove 202: Diameter 203: Diameter 230: Alignment Department 231: Aim at the Chamber AR11: Arrow AR12: Arrow C: carrier CS: cold spot CU: Arrow FL: Flash HL: Halogen lamp HS: Hotspot W: semiconductor wafer

Fig. 1 is a plan view showing the heat treatment device of the present invention. Figure 2 is a front view of the heat treatment device of Figure 1; Fig. 3 is a longitudinal sectional view showing the structure of the heat treatment section. Fig. 4 is a perspective view showing the overall appearance of the holding portion. Figure 5 is a top view of the base. Figure 6 is a cross-sectional view of the base. Figure 7 is a top view of the transfer mechanism. Figure 8 is a side view of the transfer mechanism. Fig. 9 is a plan view showing the arrangement of a plurality of halogen lamps. Fig. 10 is a diagram showing a single crystal silicon semiconductor wafer with a (100) plane orientation. FIG. 11 is a diagram showing the positional relationship between the semiconductor wafer held on the base and the halogen lamp. Fig. 12 is a diagram showing another example of the positional relationship between the semiconductor wafer and the halogen lamp.

201: Groove

AR11: Arrow

HL: Halogen lamp

HS: Hotspot

W: semiconductor wafer

Claims (10)

A heat treatment method, characterized in that it heats the substrate by irradiating the substrate with light, and includes: The holding process, which holds the substrate on the base in the chamber; and An irradiating step, which irradiates light from a light irradiating portion to the substrate held on the base; and In the holding step, the substrate is held on the susceptor in the following direction, that is, in the direction that occurs along the <100> direction of the crystal orientation of the substrate when the substrate is irradiated with light in the irradiation step The temperature gradient is smaller than the temperature gradient along the <110> direction. Such as the heat treatment method of claim 1, where The light irradiating part includes a plurality of rod-shaped lamps arranged in a grid pattern in two stages in a rectangular light source area, In the holding step, the substrate is held on the base such that the <100> direction of the crystal orientation of the substrate coincides with the longitudinal direction of the rod lamp. Such as the heat treatment method of claim 1, where The light irradiation section includes a plurality of rod-shaped lamps arranged in parallel in a rectangular light source area, In the holding step, the substrate is held on the base such that the <110> direction of the crystal orientation of the substrate coincides with the longitudinal direction of the rod lamp. Such as the heat treatment method of claim 2 or 3, where The above-mentioned rod lamp is a continuous lighting lamp. Such as the heat treatment method of claim 3, where The above rod lights are flash lights. A heat treatment device, characterized in that it heats the substrate by irradiating the substrate with light, and includes: The chamber contains the substrate; A base, which holds the above-mentioned substrate in the above-mentioned cavity; A light irradiating part irradiating light to the substrate held on the base; and Alignment portion, which adjusts the direction of the substrate held on the base; The alignment section adjusts the substrate in such a way that the temperature gradient generated along the <100> direction of the crystal orientation of the substrate when light is irradiated from the light irradiation section to the substrate is smaller than the temperature gradient generated along the <110> direction The direction. Such as the heat treatment device of claim 6, where The light irradiating part includes a plurality of rod-shaped lamps arranged in a grid in two stages in a rectangular light source area, The alignment portion adjusts the direction of the substrate so that the <100> direction of the crystal orientation of the substrate coincides with the longitudinal direction of the rod lamp. Such as the heat treatment device of claim 6, where The light irradiation section includes a plurality of rod-shaped lamps arranged in parallel in a rectangular light source area, The alignment part adjusts the direction of the substrate so that the <110> direction of the crystal orientation of the substrate coincides with the longitudinal direction of the rod lamp. Such as the heat treatment device of claim 7 or 8, where The above-mentioned rod lamp is a continuous lighting lamp. Such as the heat treatment device of claim 8, where The above rod lights are flash lights.

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