Heat treatment method and heat treatment apparatus

Abstract

To provide a thermal treatment method capable of efficiently reflecting thermal treatment with a film thickness measurement result, and a thermal treatment device.SOLUTION: A film thickness measurement unit for measuring a film thickness of a thin film formed in a semiconductor wafer is mounted inside of a thermal treatment device. The film thickness of the thin film formed on a surface of the semiconductor wafer before performing thermal treatment by a thermal treatment unit is measured. The thermal treatment unit performs preheating using a halogen lamp and flash heating using a flash lamp on the semiconductor wafer. Even after the thermal treatment is performed by the thermal treatment unit, the film thickness of the thin film formed on the surface of the semiconductor wafer is measured. A film thickness change caused by the thermal treatment is calculated from film thickness measurements before and after the thermal treatment, and a treatment condition of the thermal treatment in the thermal treatment unit is adjusted in accordance with the film thickness change.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a heat treatment method and a heat treatment apparatus for heating a thin precision electronic substrate (hereinafter simply referred to as "substrate") such as a semiconductor wafer by irradiating the substrate with flash light. [Background technology]

[0002] Flash lamp annealing (FLA), which heats semiconductor wafers in an extremely short time, is attracting attention in the semiconductor device manufacturing process.Flash lamp annealing is a heat treatment technology that uses a xenon flash lamp (hereinafter, simply referred to as "flash lamp" means a xenon flash lamp) to irradiate the surface of a semiconductor wafer with flash light, thereby raising the temperature of only the surface of the semiconductor wafer in an extremely short time (a few milliseconds or less).

[0003] The spectral distribution of radiation from a xenon flash lamp is in the ultraviolet to near-infrared range, with a shorter wavelength than conventional halogen lamps and a wavelength that roughly matches the fundamental absorption band of silicon semiconductor wafers. Therefore, when a semiconductor wafer is irradiated with flash light from a xenon flash lamp, little light is transmitted, making it possible to rapidly heat the semiconductor wafer. It has also been found that if the flash light is irradiated for an extremely short period of time, less than a few milliseconds, it is possible to selectively heat only the area near the surface of the semiconductor wafer.

[0004] Flash lamp annealing is used in processes that require heating for an extremely short period of time, such as activating impurities implanted in a semiconductor wafer. By irradiating the surface of a semiconductor wafer into which impurities have been implanted by ion implantation with a flash light from a flash lamp, the surface of the semiconductor wafer can be heated to the activation temperature in an extremely short period of time, allowing only the impurities to be activated without diffusing them deeply.

[0005] In recent years, attempts have been made to apply flash lamp annealing to the heat treatment of thin films. For example, studies have been conducted to form an oxide film by irradiating a semiconductor wafer with flash light in an oxidizing atmosphere such as oxygen, or to form a nitride film by irradiating a semiconductor wafer with flash light in a nitriding atmosphere such as ammonia. Patent Document 1 also discloses modifying polysilicon by irradiating a polysilicon film with flash light from a flash lamp. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2019-149521 Summary of the Invention [Problem to be solved by the invention]

[0007] When performing heat treatment on thin films, controlling the film thickness is important. When forming films such as oxide films using flash lamp annealing, it is necessary to measure the film thickness before and after the heat treatment to determine the amount of film formed. Furthermore, when using flash lamp annealing to crystallize amorphous silicon films or modify polysilicon films, it is necessary to measure the film thickness before and after the heat treatment to evaluate the process. Generally, evaluation of the crystallization of polysilicon films is performed using physical analysis such as XRD or EBSD, but these methods require a considerable amount of time because they use X-rays or electron beams, so film thickness measurements are performed before and after the heat treatment to perform a simple evaluation.

[0008] To measure film thickness before and after flash lamp annealing, a film thickness measurement device must be installed separately from the heat treatment equipment equipped with flash lamps, and semiconductor wafers must be transported into the film thickness measurement device before and after heat treatment to measure film thickness. However, this requires frequent transport of semiconductor wafers between the heat treatment equipment and the film thickness measurement device before and after heat treatment, which increases the number of processes and reduces productivity. Furthermore, in order to reflect the film thickness measurement results, the equipment operator must determine the process conditions of the heat treatment equipment by trial and error based on the measurement results obtained by the film thickness measurement device, further reducing productivity.

[0009] The present invention has been made in view of the above-mentioned problems, and has an object to provide a heat treatment method and a heat treatment apparatus that can efficiently reflect the film thickness measurement results in the heat treatment. [Means for solving the problem]

[0010] In order to solve the above-mentioned problems, the invention of claim 1 provides a heat treatment method for heating a substrate by irradiating the substrate with flash light, the method comprising: a film thickness measurement step for measuring a film thickness of a thin film formed on the substrate; a preheating step for heating the substrate by irradiating the substrate with light from a continuously lit lamp; and a flash heating step for heating the substrate by irradiating the substrate with flash light from a flash lamp, The film thickness measuring step includes a first film thickness measuring step of measuring a film thickness before the preheating step and the flash heating step are performed, and a second film thickness measuring step of measuring a film thickness after the preheating step and the flash heating step are performed, and a film thickness variation is measured according to a film thickness variation that is a difference between the film thickness measured in the first film thickness measuring step and the film thickness measured in the second film thickness measuring step. The method is characterized in that the processing conditions in the preheating step and the flash heating step are adjusted.

[0012] Also, claims 2 The invention of The invention of claim 1 In the heat treatment method according to the present invention, the voltage applied to the flash lamp in the flash heating step is adjusted in accordance with the film thickness measured in the film thickness measuring step.

[0013] Also, claims 3 The invention of The invention of claim 1In the heat treatment method according to the above aspect, the preheating temperature at which the substrate is heated in the preheating step is adjusted in accordance with the film thickness measured in the film thickness measuring step.

[0014] Also, claims 4 The present invention provides a heat treatment apparatus for heating a substrate by irradiating the substrate with flash light, the heat treatment apparatus comprising: a film thickness measurement unit for measuring the film thickness of a thin film formed on the substrate; and a heat treatment unit for performing heat treatment on the substrate, the heat treatment unit including a continuously lit lamp for irradiating the substrate with light to heat the substrate, and a flash lamp for irradiating the substrate with flash light to heat the substrate, The film thickness measuring unit measures the film thickness before the heat treatment unit performs the heat treatment on the substrate, and measures the film thickness after the heat treatment unit performs the heat treatment on the substrate, and determines a film thickness variation that is a difference between the film thickness measured before the heat treatment and the film thickness measured after the heat treatment. The processing conditions in the heat treatment section are adjusted.

[0016] Also, claims 5 The invention of The invention of claim 4 In the heat treatment apparatus according to the above aspect, the voltage applied to the flash lamp is adjusted in accordance with the film thickness measured by the film thickness measuring unit.

[0017] Also, claims 6 The invention of The invention of claim 4 In the heat treatment apparatus according to the above aspect, a preheating temperature at which the substrate is heated by light irradiation from the continuously lit lamp is adjusted in accordance with the film thickness measured by the film thickness measuring unit. [Effects of the Invention]

[0018] Claims 1 to 1 3 According to the invention, the processing conditions in the preheating step and the flash heating step are adjusted according to the film thickness measured in the film thickness measurement step, so that the film thickness measurement results are automatically fed back to the processing conditions, and the film thickness measurement results can be efficiently reflected in the heat treatment.

[0019] Claim 4 From claims 6According to the invention, the processing conditions in the thermal processing unit are adjusted according to the film thickness measured by the film thickness measuring unit, so that the film thickness measurement results are automatically fed back to the processing conditions, and the film thickness measurement results can be efficiently reflected in the thermal processing. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a plan view showing a heat treatment apparatus according to the present invention; [Figure 2] FIG. 2 is a vertical cross-sectional view showing the configuration of a heat treatment unit. [Figure 3] FIG. 2 is a perspective view showing the overall appearance of the holding portion. [Figure 4] FIG. [Figure 5] FIG. 2 is a cross-sectional view of a susceptor. [Figure 6] FIG. [Figure 7] FIG. [Figure 8] FIG. 2 is a plan view showing the arrangement of a plurality of halogen lamps. [Figure 9] FIG. 2 is a diagram showing a schematic configuration of a film thickness measuring unit. [Figure 10] 2 is a flowchart showing a procedure of a processing operation in the heat treatment apparatus of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0022] FIG. 1 is a plan view showing a heat treatment apparatus 100 according to the present invention. The heat treatment apparatus 100 is a flash lamp annealing apparatus that irradiates a disk-shaped semiconductor wafer W as a substrate with flash light to heat the semiconductor wafer W. The size of the semiconductor wafer W to be treated is not particularly limited, but may be, for example, φ300 mm or φ450 mm. In FIG. 1 and the subsequent figures, the dimensions and number of each part are exaggerated or simplified as necessary for ease of understanding. Also, in FIG. 1 and the following figures, 2 toIn order to clarify the directional relationship, an XYZ Cartesian coordinate system is attached, with the Z axis direction being the vertical direction and the XY plane being the horizontal plane.

[0023] The heat treatment apparatus 100 includes an indexer unit 110 for loading unprocessed semiconductor wafers W into the apparatus from outside and unloading processed semiconductor wafers W from the apparatus, an alignment unit 230 for positioning the unprocessed semiconductor wafers W, a path 290 for transferring the semiconductor wafers W, two cooling units 130 and 140 for cooling the semiconductor wafers W after heat treatment, a film thickness measurement unit 300 for measuring the film thickness of a thin film formed on the semiconductor wafers W, an inspection unit 400 for inspecting the semiconductor wafers W, and a heat treatment unit 160 for flash heating the semiconductor wafers W. The heat treatment apparatus 100 also includes a transfer robot 150 for transferring the semiconductor wafers W to and from the cooling units 130 and 140, the film thickness measurement unit 300, the inspection unit 400, and the heat treatment unit 160. The heat treatment apparatus 100 also includes a control unit 3 for controlling the operation mechanisms provided in each of the above-mentioned processing units and the transfer robot 150 to proceed with the flash heating of the semiconductor wafers W.

[0024] The indexer unit 110 is disposed at an end of the heat treatment apparatus 100. The indexer unit 110 includes three load ports 111 and a transfer robot 120. The three load ports 111 are arranged side by side along the Y-axis direction at the end of the heat treatment apparatus 100. Each load port 111 can accommodate one carrier C. Thus, a maximum of three carriers C can be placed in the indexer unit 110. Carriers C containing unprocessed semiconductor wafers W are transported by an automated guided vehicle (AGV, OHT) or the like and placed on the load port 111. Carriers C containing processed semiconductor wafers W are also removed from the load port 111 by the automated guided vehicle. A dummy carrier containing a dummy wafer may be placed on one of the three load ports 111.

[0025] Furthermore, in the load port 111, the carriers C are configured to be movable up and down so that the transfer robot 120 can load and unload any semiconductor wafers W into and from the carriers C. Note that the form of the carriers C may be a FOUP (front opening unified pod) that stores semiconductor wafers W in an enclosed space, a SMIF (Standard Mechanical Interface) pod, or an OC (open cassette) that exposes the stored semiconductor wafers W to the outside air.

[0026] The transfer robot 120 is configured to be capable of sliding movement along the Y-axis direction, rotating movement around the Z-axis, and moving up and down along the Z-axis. As a result, the transfer robot 120 takes in and out semiconductor wafers W from carriers C placed on any of the load ports 111, and also transfers semiconductor wafers W to and from the alignment unit 230 and path 290. The transfer robot 120 takes in and out semiconductor wafers W from carriers C by sliding movement of the hand 121 and moving up and down the carrier C. The transfer of semiconductor wafers W between the transfer robot 120 and the alignment unit 230 or path 290 is performed by sliding movement of the hand 121 and moving up and down the transfer robot 120.

[0027] The alignment unit 230 and path 290 are sandwiched between the indexer unit 110 and the transfer chamber 170 and are installed to connect the two. The alignment unit 230 is a processing unit that rotates the semiconductor wafer W in a horizontal plane to orient it in an appropriate direction for flash heating. The alignment unit 230 is configured inside an alignment chamber 231, which is an aluminum alloy housing, and includes a mechanism for supporting and rotating the semiconductor wafer W in a horizontal position, and a mechanism for optically detecting notches, orientation flats, and the like formed on the peripheral edge of the semiconductor wafer W.

[0028] The alignment chamber 231 is provided with two openings for loading and unloading the semiconductor wafer W. Of the two openings of the alignment chamber 231, the opening connected to the indexer unit 110 can be opened and closed by a gate valve 232. On the other hand, of the two openings, the opening connected to the transfer chamber 170 can be opened and closed by a gate valve 233. That is, the alignment chamber 231 and the indexer unit 110 are connected via the gate valve 232, and the alignment chamber 231 and the transfer chamber 170 are connected via the gate valve 233.

[0029] The gate valve 232 is opened when the semiconductor wafer W is transferred between the indexer unit 110 and the alignment chamber 231. The gate valve 233 is opened when the semiconductor wafer W is transferred between the alignment chamber 231 and the transfer chamber 170. When the gate valves 232 and 233 are closed, the interior of the alignment chamber 231 becomes an airtight space.

[0030] In the alignment unit 230, the semiconductor wafer W received from the delivery robot 120 of the indexer unit 110 is rotated around a vertical axis with the center of the semiconductor wafer W as the center of rotation, and the orientation of the semiconductor wafer W is adjusted by optically detecting a notch or the like. After the orientation adjustment is completed, the semiconductor wafer W is removed from the alignment unit 230 by the transfer robot 150.

[0031] The path 290 is provided for transferring the semiconductor wafer W between the delivery robot 120 and the transfer robot 150. The path 290 is configured by providing a plurality of pins inside a pass chamber 291, which is a housing made of an aluminum alloy. The pass chamber 291 has two openings for transferring the semiconductor wafer W in and out. Of the two openings of the pass chamber 291, the opening connected to the indexer unit 110 can be opened and closed by a gate valve 292. On the other hand, of the two openings, the opening connected to the transfer chamber 170 can be opened and closed by a gate valve 293. That is, the pass chamber 291 and the indexer unit 110 are connected via the gate valve 292, and the pass chamber 291 and the transfer chamber 170 are connected via the gate valve 293.

[0032] The gate valve 292 is opened when the semiconductor wafer W is transferred between the indexer unit 110 and the pass chamber 291. The gate valve 293 is opened when the semiconductor wafer W is transferred between the pass chamber 291 and the transfer chamber 170. When the gate valves 292 and 293 are closed, the inside of the pass chamber 291 becomes an airtight space.

[0033] The path 290 transfers the semiconductor wafer W between the delivery robot 120 and the transport robot 150 by receiving the semiconductor wafer W from one of them and then taking it out from the other. Note that the transfer of the semiconductor wafer W between the delivery robot 120 and the transport robot 150 can also be performed via the alignment unit 230. In other words, the alignment unit 230 can also function as a path.

[0034] The transfer robot 150 is housed in a transfer chamber 170. Around the transfer chamber 170, an alignment chamber 231, a pass chamber 291, a cool chamber 131 of the cooling unit 130, a cool chamber 141 of the cooling unit 140, a film thickness measurement chamber 301 of the film thickness measurement unit 300, an inspection chamber 401 of the inspection unit 400, and a processing chamber 6 of the heat treatment unit 160 are connected.

[0035] The transfer robot 150 installed in the transfer chamber 170 is capable of rotating around a vertical axis as indicated by arrow 150R. The transfer robot 150 has two link mechanisms consisting of multiple arm segments, and transfer hands 151a and 151b that hold semiconductor wafers W are attached to the tips of the two link mechanisms. These transfer hands 151a and 151b are arranged vertically at a predetermined pitch apart, and are each capable of sliding linearly and independently in the same horizontal direction via the link mechanisms. The transfer robot 150 also moves the two transfer hands 151a and 151b up and down while maintaining the predetermined pitch apart by raising and lowering the base on which the two link mechanisms are attached.

[0036] When the transfer robot 150 transfers (takes in or out) a semiconductor wafer W to or from the alignment chamber 231, the pass chamber 291, the cool chambers 131, 141, the film thickness measurement chamber 301, the inspection chamber 401, or the processing chamber 6 of the heat treatment unit 160, first, both transfer hands 151a, 151b rotate so as to face the transfer target. After that (or while rotating), the transfer robot 150 raises and lowers the transfer hands 151a, 151b to position one of the transfer hands at the same height as the opening of the transfer target. Then, the transfer robot 150 slides the transfer hand 151a (151b) linearly in the horizontal direction to transfer the semiconductor wafer W to or from the transfer target.

[0037] The heat treatment section 160, which is the main part of the heat treatment apparatus 100, is a substrate treatment section that performs flash heating by irradiating a preheated semiconductor wafer W with a flash of light (flash light) from xenon flash lamps FL. A gate valve 185 is provided between the transfer chamber 170 and the treatment chamber 6 of the heat treatment section 160. The gate valve 185 is opened when the semiconductor wafer W is transferred between the treatment chamber 6 of the heat treatment section 160 and the transfer chamber 170. The detailed configuration of the heat treatment section 160 will be described later.

[0038] The two cooling units 130, 140 have roughly the same configuration. The cooling units 130, 140 each include a metal cooling plate and a quartz plate placed on the top surface of the metal cooling plate inside cool chambers 131, 141, which are aluminum alloy housings (both not shown). The temperature of the cooling plate is regulated to room temperature (approximately 23°C) by a Peltier element or constant temperature water circulation. The semiconductor wafer W that has been subjected to flash heating in the heat treatment unit 160 is carried into the cool chamber 131 or 141, placed on the quartz plate, and cooled.

[0039] Each of the cool chamber 131 and the cool chamber 141 has an opening formed therein for communicating with the transfer chamber 170. The opening of the cool chamber 131 can be opened and closed by a gate valve 132. On the other hand, the opening of the cool chamber 141 can be opened and closed by a gate valve 142. That is, the cool chamber 131 and the transfer chamber 170 are connected via the gate valve 132, and the cool chamber 141 and the transfer chamber 170 are connected via the gate valve 142.

[0040] When the semiconductor wafer W is transferred between the cool chamber 131 of the cooling unit 130 and the transfer chamber 170, the gate valve 132 is opened. When the semiconductor wafer W is transferred between the cool chamber 141 of the cooling unit 140 and the transfer chamber 170, the gate valve 142 is opened.

[0041] The film thickness measurement unit 300 measures the film thickness of a thin film formed on a semiconductor wafer W using, for example, a spectroscopic ellipsometry analysis technique. FIG. 9 is a diagram showing the schematic configuration of the film thickness measurement unit 300. The film thickness measurement unit 300 is configured with an optical unit 310 and a mounting table 305 inside a film thickness measurement chamber 301, which is an aluminum alloy housing. The mounting table 305 supports the semiconductor wafer W in a horizontal position. The optical unit 310 irradiates light onto the surface of the semiconductor wafer W supported on the mounting table 305 and receives the light reflected from the surface. The optical unit 310 measures the change in polarization of the reflected light for each wavelength and determines the film thickness of the thin film formed on the surface of the semiconductor wafer W based on the obtained measurement data. Note that the film thickness measurement unit 300 is not limited to the spectroscopic ellipsometer described above and may be an optical interference film thickness measurement device.

[0042] An opening 307 is formed in the film thickness measurement chamber 301 to communicate with the transfer chamber 170. The opening 307 of the film thickness measurement chamber 301 can be opened and closed by a gate valve 302. That is, the film thickness measurement chamber 301 and the transfer chamber 170 are connected via the gate valve 302. When a semiconductor wafer W is transferred between the film thickness measurement chamber 301 of the film thickness measurement unit 300 and the transfer chamber 170, the gate valve 302 is opened.

[0043] Returning to FIG. 1 , the inspection section 400 is a processing section that performs some kind of inspection, for example, detecting scratches on a semiconductor wafer W. The inspection section 400 has a predetermined inspection unit inside an inspection chamber 401, which is a housing made of aluminum alloy. The inspection unit has, for example, an imaging camera, and performs predetermined image analysis processing on image data obtained by capturing an image of the semiconductor wafer W to detect scratches on the semiconductor wafer W. Note that the inspection section 400 is not limited to a section that detects scratches on the semiconductor wafer W, and may be a processing section that detects warpage of the semiconductor wafer W, for example.

[0044] An opening is formed in the inspection chamber 401 of the inspection unit 400 for communicating with the transfer chamber 170. The opening of the inspection chamber 401 can be opened and closed by a gate valve 402. That is, the inspection chamber 401 and the transfer chamber 170 are connected via the gate valve 402. When a semiconductor wafer W is transferred between the inspection chamber 401 of the inspection unit 400 and the transfer chamber 170, the gate valve 402 is opened.

[0045] The transfer robot 150 and the delivery robot 120 constitute a transport mechanism that transports the semiconductor wafer W from the carrier C to each processing section, such as the heat treatment section 160. The transfer robot 150 is also a center robot located at the center of the cooling sections 130, 140, the film thickness measurement section 300, the inspection section 400, and the heat treatment section 160, and transports the semiconductor wafer W to each of these processing sections. The transfer of the semiconductor wafer W between the transfer robot 150 and the delivery robot 120 is performed via a path 290 or an alignment section 230. Specifically, the transfer of the semiconductor wafer W is performed by one of the transfer robot 150 or the delivery robot 120 receiving the semiconductor wafer W that the other robot has delivered to the alignment chamber 231 or the pass chamber 291.

[0046] Clean nitrogen gas is supplied from a gas supply unit to the transfer chamber 170 in which the transfer robot 150 is placed, and the atmosphere therein is exhausted by an exhaust unit (both not shown). This maintains a nitrogen atmosphere with a low oxygen concentration inside the transfer chamber 170. In addition, the cool chamber 131 of the cooling unit 130, the cool chamber 141 of the cooling unit 140, the film thickness measurement chamber 301 of the film thickness measurement unit 300, and the inspection chamber 401 of the inspection unit 400 are each provided with a gas supply unit and an exhaust unit, and the interiors thereof are kept in a nitrogen atmosphere. Furthermore, nitrogen gas is also supplied from a gas supply unit to the alignment chamber 231 and the pass chamber 291, and the interiors thereof can be exhausted by an exhaust unit.

[0047] Next, the configuration of the heat treatment section 160 will be described. Fig. 2 is a longitudinal cross-sectional view showing the configuration of the heat treatment section 160. The heat treatment section 160 includes a processing chamber 6 that accommodates a semiconductor wafer W and performs a heat treatment thereon, a flash lamp house 5 that houses multiple flash lamps FL, and a halogen lamp house 4 that houses multiple halogen lamps HL. The flash lamp house 5 is provided above the processing chamber 6, and the halogen lamp house 4 is provided below it. The heat treatment section 160 also includes, inside the processing chamber 6, a holder 7 that holds the semiconductor wafer W in a horizontal position, and a transfer mechanism 10 that transfers the semiconductor wafer W between the holder 7 and the transfer robot 150.

[0048] The processing chamber 6 is constructed by attaching quartz chamber windows to the top and bottom of a cylindrical chamber side portion 61. The chamber side portion 61 has a roughly cylindrical shape with openings at the top and bottom, with the upper opening attached and closed by an upper chamber window 63, and the lower opening attached and closed by a lower chamber window 64. The upper chamber window 63, which forms the ceiling of the processing chamber 6, is a disc-shaped member made of quartz and functions as a quartz window that transmits flash light emitted from the flash lamp FL into the processing chamber 6. The lower chamber window 64, which forms the floor of the processing chamber 6, is also a disc-shaped member made of quartz and functions as a quartz window that transmits light from the halogen lamp HL into the processing chamber 6.

[0049] Furthermore, a reflective ring 68 is attached to the upper part of the inner wall surface of the chamber side 61, and a reflective ring 69 is attached to the lower part. Both reflective rings 68, 69 are formed in an annular shape. The upper reflective ring 68 is attached by fitting it from the upper side of the chamber side 61. On the other hand, the lower reflective ring 69 is attached by fitting it from the lower side of the chamber side 61 and fastening it with screws (not shown). In other words, both reflective rings 68, 69 are detachably attached to the chamber side 61. The internal space of the processing chamber 6, i.e., the space surrounded by the upper chamber window 63, the lower chamber window 64, the chamber side 61, and the reflective rings 68, 69, is defined as a heat treatment space 65.

[0050] By attaching the reflecting rings 68, 69 to the chamber side portion 61, a recess 62 is formed on the inner wall surface of the processing chamber 6. That is, the recess 62 is formed by a central portion of the inner wall surface of the chamber side portion 61 where the reflecting rings 68, 69 are not attached, the lower end surface of the reflecting ring 68, and the upper end surface of the reflecting ring 69. 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 holder 7 that holds the semiconductor wafer W. The chamber side portion 61 and the reflecting rings 68, 69 are made of a metal material (e.g., stainless steel) that has excellent strength and heat resistance.

[0051] Furthermore, a transfer opening (furnace port) 66 is formed in the chamber side portion 61, through which a semiconductor wafer W is loaded into and unloaded from the processing chamber 6. The transfer opening 66 can be opened and closed by a gate valve 185. The transfer opening 66 is connected to the outer peripheral surface of the recessed portion 62. Therefore, when the gate valve 185 opens the transfer opening 66, the semiconductor wafer W can be loaded into and unloaded from the heat treatment space 65 through the transfer opening 66 and the recessed portion 62. Furthermore, when the gate valve 185 closes the transfer opening 66, the heat treatment space 65 within the processing chamber 6 becomes an airtight space.

[0052] Furthermore, through holes 61a and 61b are formed in the chamber side portion 61. The through hole 61a is a cylindrical hole for guiding infrared light radiated from the upper surface of a semiconductor wafer W held on a susceptor 74 (described later) to the infrared sensor 29 of the upper radiation thermometer 25. On the other hand, the through hole 61b is a cylindrical hole for guiding infrared light radiated from the lower surface of the semiconductor wafer W to the infrared sensor 24 of the lower radiation thermometer 20. The through holes 61a and 61b are provided at an angle with respect to the horizontal direction so that their axes of penetration intersect with the main surface of the semiconductor wafer W held on the susceptor 74. A transparent window 26 made of calcium fluoride material that transmits infrared light in a wavelength range measurable by the upper radiation thermometer 25 is attached to the end of the through hole 61a facing the heat treatment space 65. Furthermore, a transparent window 21 made of barium fluoride material that transmits infrared light in the wavelength range that can be measured by the lower radiation thermometer 20 is attached to the end of the through hole 61b facing the heat treatment space 65.

[0053] Furthermore, gas supply holes 81 are formed in the upper part of the inner wall of the processing chamber 6 to supply processing gas to the heat treatment space 65. The gas supply holes 81 are formed at a position above the recessed portion 62 and may be provided in the reflecting ring 68. The gas supply holes 81 are connected to a gas supply pipe 83 via a buffer space 82 formed in an annular shape inside the side wall of the processing chamber 6. The gas supply pipe 83 is connected to a processing gas supply source 85. A valve 84 is inserted in the gas supply pipe 83. When the valve 84 is opened, processing gas is supplied from the processing gas supply source 85 to the buffer space 82. The processing gas that has flowed into the buffer space 82 spreads within the buffer space 82, which has lower fluid resistance than the gas supply holes 81, and is supplied from the gas supply holes 81 into the heat treatment space 65. The processing gas may be an inert gas such as nitrogen (N2), argon (Ar), or helium (He), or a reactive gas such as hydrogen (H2), ammonia (NH3), oxygen (O2), ozone (O3), nitric oxide (NO), nitrous oxide (N2O), or nitrogen dioxide (NO2).

[0054] Meanwhile, a gas exhaust hole 86 is formed in the lower part of the inner wall of the processing chamber 6 to exhaust gas from the heat treatment space 65. The gas exhaust hole 86 is formed below the recess 62 and may be provided in the reflecting ring 69. The gas exhaust hole 86 is connected to a gas exhaust pipe 88 via a buffer space 87 formed in an annular shape inside the side wall of the processing chamber 6. The gas exhaust pipe 88 is connected to an exhaust mechanism 190. A valve 89 is inserted in the gas exhaust pipe 88. When the valve 89 is opened, the gas in the heat treatment space 65 is exhausted from the gas exhaust hole 86 through the buffer space 87 to the gas exhaust pipe 88. The gas supply hole 81 and the gas exhaust hole 86 may be provided in multiple numbers along the circumferential direction of the processing chamber 6, or may be slit-shaped. The processing gas supply source 85 and the exhaust mechanism 190 may be mechanisms provided in the heat treatment apparatus 100 or may be utilities of a factory where the heat treatment apparatus 100 is installed.

[0055] A gas exhaust pipe 191 for discharging gas from the heat treatment space 65 is also connected to the tip of the transfer opening 66. The gas exhaust pipe 191 is connected to an exhaust mechanism 190 via a valve 192. By opening the valve 192, the gas from the processing chamber 6 is exhausted through the transfer opening 66.

[0056] 3 is a perspective view showing the overall appearance of the holder 7. The holder 7 is configured to include a base ring 71, a connecting portion 72, and a susceptor 74. The base ring 71, the connecting portion 72, and the susceptor 74 are all made of quartz. In other words, the entire holder 7 is made of quartz.

[0057] The base ring 71 is an arc-shaped quartz member with a portion missing from the annular shape. This missing portion is provided to prevent interference between the base ring 71 and a transfer arm 11 of the transfer mechanism 10, which will be described later. The base ring 71 is placed on the bottom surface of the recess 62, and is supported by the wall surface of the processing chamber 6 (see FIG. 2). A plurality of connecting portions 72 (four in this embodiment) are erected on the upper surface of the base ring 71 along the circumferential direction of the annular shape. The connecting portions 72 are also quartz members, and are fixed to the base ring 71 by welding.

[0058] The susceptor 74 is supported by four connecting portions 72 provided on the base ring 71. FIG. 4 is a plan view of the susceptor 74. FIG. 5 is a cross-sectional view of the susceptor 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 member made 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 planar size larger than that of the semiconductor wafer W.

[0059] A guide ring 76 is installed on the periphery of the upper surface of the holding plate 75. The guide ring 76 is an annular member having an inner diameter larger than the diameter of the semiconductor wafer W. For example, if the diameter of the semiconductor wafer W is φ300 mm, the inner diameter of the guide ring 76 is φ320 mm. The inner periphery of the guide ring 76 has a tapered surface that widens upward from the holding plate 75. The guide ring 76 is made of quartz, the same 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 a separately processed pin or the like. Alternatively, the holding plate 75 and the guide ring 76 may be processed as an integrated member.

[0060] The area of ​​the upper surface of the holding plate 75 that is inside the guide ring 76 is a flat holding surface 75a that holds the semiconductor wafer W. A plurality of substrate support pins 77 are provided on the holding surface 75a of the holding plate 75. In this embodiment, a total of 12 substrate support pins 77 are provided at 30° intervals along a circumference concentric with the outer circumferential circle of the holding surface 75a (the inner circumferential circle of the guide ring 76). The diameter of the circle on which the 12 substrate support pins 77 are arranged (the distance between opposing substrate support pins 77) is smaller than the diameter of the semiconductor wafer W. If the diameter of the semiconductor wafer W is 300 mm, the diameter is 270 mm to 280 mm (270 mm in this embodiment). Each substrate support pin 77 is made 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 machined integrally with the holding plate 75.

[0061] Returning to FIG. 3 , four connecting portions 72 erected on the base ring 71 are fixed to the peripheral portion of the holding plate 75 of the susceptor 74 by welding. That is, the susceptor 74 and the base ring 71 are fixedly connected by the connecting portions 72. The base ring 71 of the holding portion 7 is supported on the wall surface of the processing chamber 6, and the holding portion 7 is thereby attached to the processing chamber 6. When the holding portion 7 is attached to the processing chamber 6, the holding plate 75 of the susceptor 74 is in a horizontal position (a position in which the normal line coincides with the vertical direction). That is, the holding surface 75a of the holding plate 75 is in a horizontal plane.

[0062] The semiconductor wafer W loaded into the processing chamber 6 is placed and held in a horizontal position on the susceptor 74 of the holder 7 attached to the processing chamber 6. At this time, the semiconductor wafer W is supported by twelve substrate support pins 77 standing on a holding plate 75 and held on the susceptor 74. More precisely, the upper ends of the twelve substrate support pins 77 contact the underside of the semiconductor wafer W to support the semiconductor wafer W. The heights of the twelve 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 uniform, so the twelve substrate support pins 77 can support the semiconductor wafer W in a horizontal position.

[0063] Furthermore, the semiconductor wafer W is supported by a plurality of substrate support pins 77 at a predetermined distance from the holding surface 75a of the holding plate 75. 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 semiconductor wafer W supported by the plurality of substrate support pins 77 from shifting in the horizontal direction.

[0064] 3 and 4, an opening 78 is formed in the holding plate 75 of the susceptor 74, penetrating vertically. The opening 78 is provided so that the lower radiation thermometer 20 can receive radiation (infrared light) emitted from the underside of the semiconductor wafer W. That is, the lower radiation thermometer 20 receives the light emitted from the underside of the semiconductor wafer W through the opening 78 and a transparent window 21 attached to the through-hole 61b of the chamber side 61, thereby measuring the temperature of the semiconductor wafer W. Furthermore, the holding plate 75 of the susceptor 74 is formed with four through-holes 79 through which lift pins 12 of the transfer mechanism 10, which will be described later, pass to transfer the semiconductor wafer W.

[0065] FIG. 6 is a plan view of the transfer mechanism 10. FIG. 7 is a side view of the transfer mechanism 10. The transfer mechanism 10 includes two transfer arms 11. The transfer arms 11 are arc-shaped so as to fit roughly along the annular recess 62. Two lift pins 12 are provided upright on each of the transfer arms 11. Each transfer arm 11 is rotatable by a horizontal movement mechanism 13. The horizontal movement mechanism 13 horizontally moves the pair of transfer arms 11 between a transfer operation position (position indicated by a solid line in FIG. 6) where the pair of transfer arms 11 transfer a semiconductor wafer W to the holder 7 and a retracted position (position indicated by a two-dot chain line in FIG. 6) where the pair of transfer arms 11 do not overlap the semiconductor wafer W held by the holder 7 in a plan view. The transfer operation position is below the susceptor 74, and the retracted position is outward of the susceptor 74. The horizontal movement mechanism 13 may be one that rotates each transfer arm 11 using an individual motor, or one that uses a link mechanism to rotate a pair of transfer arms 11 in conjunction with one another using a single motor.

[0066] Furthermore, the pair of transfer arms 11 are raised and lowered together with the horizontal movement 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 lift pins 12 pass through through holes 79 (see FIGS. 3 and 4 ) formed in the susceptor 74, and the upper ends of the lift pins 12 protrude from the upper surface of the susceptor 74. On the other hand, when the lifting mechanism 14 lowers the pair of transfer arms 11 to the transfer operation position to remove the lift pins 12 from the through holes 79, and the horizontal movement mechanism 13 moves the pair of transfer arms 11 so as to open, each transfer arm 11 moves to a retracted position. The retracted position of the pair of transfer arms 11 is directly above the base ring 71 of the holder 7. Because the base ring 71 is placed on the bottom surface of the recess 62, the retracted position of the transfer arms 11 is inside the recess 62. In addition, an exhaust mechanism (not shown) is also provided near the location where the drive part of the transfer mechanism 10 (horizontal movement mechanism 13 and lifting mechanism 14) is located, and is configured to exhaust the atmosphere around the drive part of the transfer mechanism 10 to the outside of the processing chamber 6.

[0067] As shown in FIG. 2, the processing chamber 6 is provided with two radiation thermometers (pyrometers in this embodiment): an upper radiation thermometer 25 and a lower radiation thermometer 20. The upper radiation thermometer 25 is installed diagonally above the semiconductor wafer W held on the susceptor 74 and receives infrared light radiated from the top surface of the semiconductor wafer W to measure the temperature of the top surface. The infrared sensor 29 of the upper radiation thermometer 25 is equipped with an InSb (indium antimonide) optical element so as to be able to respond to a sudden temperature change on the top surface of the semiconductor wafer W at the moment when the flash light is irradiated. On the other hand, the lower radiation thermometer 20 is installed diagonally below the semiconductor wafer W held on the susceptor 74 and receives infrared light radiated from the bottom surface of the semiconductor wafer W to measure the temperature of the bottom surface.

[0068] The flash lamp house 5, which is provided above the processing chamber 6, is configured to include a light source made up of multiple (30 in this embodiment) xenon flash lamps FL inside a housing 51, and a reflector 52 provided to cover the light source from above. A lamp light emission window 53 is attached to the bottom of the housing 51 of the flash lamp house 5. The lamp light emission window 53, which forms the floor of the flash lamp house 5, is a plate-shaped quartz window made of quartz. By installing the flash lamp house 5 above the processing chamber 6, the lamp light emission window 53 faces an upper chamber window 63. The flash lamps FL irradiate a heat treatment space 65 with flash light from above the processing chamber 6 through the lamp light emission window 53 and the upper chamber window 63.

[0069] The multiple flash lamps FL are each a rod-shaped lamp having a long cylindrical shape, and are arranged in a plane so that their longitudinal directions are parallel to each other along the main surface of the semiconductor wafer W held by the holder 7 (i.e., along the horizontal direction). Therefore, the plane formed by the arrangement of the flash lamps FL is also a horizontal plane.

[0070] A xenon flash lamp FL comprises a rod-shaped glass tube (discharge tube) filled with xenon gas and fitted with an anode and cathode connected to a capacitor at both ends, and a trigger electrode attached to the outer surface of the glass tube. Because xenon gas is an electrical insulator, electricity does not flow through the glass tube under normal conditions, even if a charge is stored in the capacitor. However, when a high voltage is applied to the trigger electrode, causing the insulation to break down, the electricity stored in the capacitor flows instantaneously through the glass tube, exciting the xenon atoms or molecules and emitting light. In such a xenon flash lamp FL, electrostatic energy previously stored in the capacitor is converted into extremely short light pulses of 0.1 to 100 milliseconds, enabling it to emit extremely intense light compared to continuous light sources such as halogen lamps HL. In other words, a flash lamp FL is a pulsed lamp that emits light instantaneously for an extremely short period of time, less than one second. The light emission time of the flash lamp FL can be adjusted by adjusting the coil constant of the lamp power supply that supplies power to the flash lamp FL.

[0071] Furthermore, reflector 52 is provided above the multiple flash lamps FL so as to cover them entirely. The basic function of reflector 52 is to reflect the flash light emitted from the multiple flash lamps FL toward the heat treatment space 65. Reflector 52 is made of an aluminum alloy plate, and its surface (the surface facing the flash lamps FL) is roughened by blasting.

[0072] The halogen lamp house 4 provided below the processing chamber 6 has a plurality of (40 in this embodiment) halogen lamps HL built in inside a housing 41. The plurality of halogen lamps HL irradiate light from below the processing chamber 6 through a lower chamber window 64 into a heat treatment space 65.

[0073] 8 is a plan view showing the arrangement of multiple halogen lamps HL. In this embodiment, 20 halogen lamps HL are arranged in each of two upper and lower rows. Each halogen lamp HL is a rod-shaped lamp having a long cylindrical shape. The 20 halogen lamps HL in both the upper and lower rows are arranged so that their longitudinal directions are parallel to each other along the main surface of the semiconductor wafer W held by the holder 7 (i.e., along the horizontal direction). Therefore, the plane formed by the arrangement of the halogen lamps HL in both the upper and lower rows is a horizontal plane.

[0074] 8, the halogen lamps HL are arranged more densely in the region facing the periphery of the semiconductor wafer W held by the holder 7 on both the upper and lower tiers than in the region facing the center of the semiconductor wafer W. That is, on both the upper and lower tiers, the halogen lamps HL are arranged at a shorter pitch in the periphery of the lamp arrangement than in the center. This allows a greater amount of light to be irradiated onto the periphery of the semiconductor wafer W, which is prone to temperature drop when heated by light irradiation from the halogen lamps HL.

[0075] The lamp group consisting of the halogen lamps HL in the upper row and the lamp group consisting of the halogen lamps HL in the lower row are arranged so as to intersect in a grid pattern. That is, a total of 40 halogen lamps HL are arranged so that the longitudinal direction of each halogen lamp HL in the upper row is perpendicular to the longitudinal direction of each halogen lamp HL in the lower row.

[0076] A halogen lamp HL is a filament-type light source that emits light by passing electricity through a filament placed inside a glass tube, causing it to incandescent. The glass tube is filled with an inert gas, such as nitrogen or argon, containing trace amounts of halogen elements (iodine, bromine, etc.). The introduction of halogen elements makes it possible to set the filament temperature at a high temperature while preventing filament breakage. Therefore, compared to standard incandescent light bulbs, halogen lamps HL have the characteristics of a longer lifespan and the ability to continuously emit strong light. In other words, halogen lamps HL are continuous lamps that emit light continuously for at least one second. Furthermore, because halogen lamps HL are rod-shaped, they have a long lifespan, and by arranging them horizontally, they achieve excellent radiation efficiency toward the semiconductor wafer W above.

[0077] Also, a reflector 43 is provided below the two-tiered halogen lamps HL inside the housing 41 of the halogen lamp house 4 (FIG. 2). The reflector 43 reflects the light emitted from the multiple halogen lamps HL toward the heat treatment space 65.

[0078] The control unit 3 controls the various operating mechanisms of the heat treatment apparatus 100. The hardware configuration of the control unit 3 is similar to that of a general computer. That is, the control unit 3 includes a CPU (central processing unit) that performs various arithmetic operations, a ROM (read-only memory) that stores basic programs, a RAM (readable and writable memory) that stores various information, and a magnetic disk that stores control software and data. The CPU of the control unit 3 executes a predetermined processing program to execute processing in the heat treatment apparatus 100. The control unit 3 also adjusts various processing conditions in the heat treatment unit 160 based on the film thickness measurement results obtained by the film thickness measurement unit 300. Note that while FIG. 1 shows the control unit 3 within the indexer unit 110, this is not limiting and the control unit 3 can be located anywhere within the heat treatment apparatus 100.

[0079] In addition to the above configuration, the heat treatment section 160 is equipped with various cooling structures to prevent excessive temperature rise in the halogen lamp house 4, flash lamp house 5, and processing chamber 6 due to the thermal energy generated by the halogen lamps HL and flash lamps FL during heat treatment of the semiconductor wafer W. For example, a water-cooling pipe (not shown) is provided in the wall of the processing chamber 6. The halogen lamp house 4 and flash lamp house 5 also have an air-cooled structure that creates a gas flow inside to remove heat. Air is also supplied to the gap between the upper chamber window 63 and the lamp light emission window 53 to cool the flash lamp house 5 and upper chamber window 63.

[0080] Next, the processing operation of the heat treatment apparatus 100 according to the present invention will be described. Fig. 10 is a flowchart showing the procedure of the processing operation in the heat treatment apparatus 100. In this embodiment, an oxide film is formed on the surface of the semiconductor wafer W by irradiating it with flash light in the heat treatment section 160. The processing procedure for the semiconductor wafer W described below progresses as the control section 3 controls each operating mechanism of the heat treatment apparatus 100.

[0081] First, a plurality of unprocessed silicon semiconductor wafers W are accommodated in a carrier C and placed on one of the three load ports 111 of the indexer unit 110. Then, the transfer robot 120 removes the unprocessed semiconductor wafers W from the carrier C (step S1). The transfer robot 120 loads the semiconductor wafers W removed from the carrier C into the alignment chamber 231 of the alignment unit 230. At this time, the gate valve 232 is opened, allowing atmosphere to flow from the indexer unit 110 into the alignment chamber 231, causing a temporary rise in the oxygen concentration inside the alignment chamber 231. After the semiconductor wafers W are loaded into the alignment chamber 231, the gate valve 232 is closed to supply nitrogen into the alignment chamber 231 and exhaust the internal atmosphere, thereby creating a nitrogen atmosphere inside the alignment chamber 231 and reducing the oxygen concentration. The gate valve 233 remains closed.

[0082] The alignment section 230 rotates the semiconductor wafer W loaded into the alignment chamber 231 around a vertical axis in a horizontal plane with its center as the center of rotation, and adjusts the orientation of the semiconductor wafer W by optically detecting a notch or the like (step S2).

[0083] Next, the gate valve 233 opens, and the transfer robot 150 transfers the semiconductor wafer W from the alignment chamber 231 to the transfer chamber 170. Then, the gate valve 302 opens, and the transfer robot 150 transfers the semiconductor wafer W into the film thickness measurement chamber 301. The film thickness measurement unit 300 measures the film thickness of the thin film formed on the surface of the semiconductor wafer W transferred into the film thickness measurement chamber 301 (step S3). In step S3, the film thickness measurement unit 300 measures the film thickness of the semiconductor wafer W before it is subjected to heat treatment in the heat treatment unit 160. Even before heat treatment, a natural oxide film is formed on the surface of the silicon semiconductor wafer W, and the film thickness measurement unit 300 measures the film thickness of this natural oxide film. The film thickness measurement result by the film thickness measurement unit 300 is transmitted to the control unit 3.

[0084] After the pre-processing film thickness measurement is completed, the transfer robot 150 transfers the semiconductor wafer W from the film thickness measurement chamber 301 to the transfer chamber 170. Then, the gate valve 185 is opened, and the transfer robot 150 transfers the semiconductor wafer W into the processing chamber 6 of the heat treatment unit 160.

[0085] Prior to loading the semiconductor wafer W into the processing chamber 6, the gas supply valve 84 is opened, and the exhaust valves 89 and 192 are also opened to start supplying and exhausting gas to and from the processing chamber 6. When the valve 84 is opened, nitrogen gas is supplied to the heat treatment space 65 through the gas supply hole 81. When the valve 89 is opened, the gas inside the processing chamber 6 is exhausted through the gas exhaust hole 86. As a result, the nitrogen gas supplied from the upper part of the heat treatment space 65 inside the processing chamber 6 flows downward and is exhausted from the lower part of the heat treatment space 65. When the valve 192 is opened, the gas inside the processing chamber 6 is also exhausted from the transfer opening 66. Furthermore, the atmosphere around the drive unit of the transfer mechanism 10 is also exhausted by an exhaust mechanism (not shown).

[0086] Next, the gate valve 185 is opened to open the transfer opening 66, and the semiconductor wafer W to be processed is loaded by the transfer robot 150 into the heat treatment space 65 in the processing chamber 6 through the transfer opening 66. The transfer robot 150 advances the transfer hand 151a (or transfer hand 151b) holding the unprocessed semiconductor wafer W to a position directly above the holder 7 and stops it. Then, the pair of transfer arms 11 of the transfer mechanism 10 move horizontally from the retracted position to the transfer operation position and rise, causing the lift pins 12 to pass through the through holes 79 and protrude from the upper surface of the holding plate 75 of the susceptor 74 to receive the semiconductor wafer W. At this time, the lift pins 12 rise to a position higher than the upper ends of the substrate support pins 77.

[0087] After the unprocessed semiconductor wafer W is placed on the lift pins 12, the transfer robot 150 causes the transfer hand 151a to withdraw from the heat treatment space 65, and the transfer opening 66 is closed by the gate valve 185. Then, the pair of transfer arms 11 descend, transferring the semiconductor wafer W from the transfer mechanism 10 to the susceptor 74 of the holder 7, where it is held horizontally from below. The semiconductor wafer W is supported by a plurality of substrate support pins 77 erected on the holding plate 75 and held on the susceptor 74. The semiconductor wafer W is held on the holder 7 with its front surface to be processed facing upward. A predetermined gap is formed between the back surface (the main surface opposite 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, which have descended to below the susceptor 74, are retracted to a retracted position, i.e., inside the recess 62, by the horizontal movement mechanism 13.

[0088] After the semiconductor wafer W is loaded into the processing chamber 6 and the transfer opening 66 is closed by the gate valve 185, an oxidizing gas (oxygen gas in this embodiment) is supplied from the processing gas supply source 85 to the heat treatment space 65. As a result, an oxidizing gas atmosphere is formed in the heat treatment space 65.

[0089] After the semiconductor wafer W is loaded into the processing chamber 6 and held on the susceptor 74, the 40 halogen lamps HL are simultaneously turned on to begin preheating (assisted heating) (step S4). The halogen light emitted from the halogen lamps HL passes through the lower chamber window 64 and the susceptor 74, both made of quartz, and is irradiated onto the underside of the semiconductor wafer W. The semiconductor wafer W is preheated by being irradiated with light from the halogen lamps HL, and its temperature rises. Note that the transfer arm 11 of the transfer mechanism 10 is retracted inside the recess 62, so it does not interfere with heating by the halogen lamps HL.

[0090] When preheating is performed by the halogen lamps HL, the temperature of the semiconductor wafer W is measured by the lower radiation thermometer 20. That is, the lower radiation thermometer 20 receives infrared light radiated from the underside of the semiconductor wafer W held on the susceptor 74 through the openings 78 and measures the wafer temperature during heating. The measured temperature of the semiconductor wafer W is transmitted to the control unit 3. The control unit 3 controls the output of the halogen lamps HL while monitoring whether the temperature of the semiconductor wafer W, which is heated by the light irradiation from the halogen lamps HL, has reached a predetermined preheating temperature T1. That is, the control unit 3 feedback-controls the output of the halogen lamps HL based on the value measured by the lower radiation thermometer 20 so that the temperature of the semiconductor wafer W becomes the preheating temperature T1.

[0091] 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 lower radiation thermometer 20 reaches the preheating temperature T1, the control unit 3 adjusts the output of the halogen lamps HL to maintain the temperature of the semiconductor wafer W at approximately the preheating temperature T1.

[0092] By performing preheating using the halogen lamps HL in this manner, the temperature of the entire semiconductor wafer W is raised uniformly to the preheating temperature T1. During preheating using the halogen lamps HL, the temperature of the peripheral portion of the semiconductor wafer W, where heat dissipation is more likely, tends to be lower than that of the central portion, but the arrangement density of the halogen lamps HL in the halogen lamp house 4 is higher in the region facing the peripheral portion of the semiconductor wafer W than in the region facing the central portion of the semiconductor wafer W. As a result, a greater amount of light is irradiated onto the peripheral portion of the semiconductor wafer W, where heat dissipation is more likely, and the in-plane temperature distribution of the semiconductor wafer W during the preheating stage can be made uniform.

[0093] When a predetermined time has elapsed since the temperature of the semiconductor wafer W reached the preheating temperature T1, the flash lamps FL irradiate the surface of the semiconductor wafer W with flash light (step S5). At this time, part of the flash light emitted from the flash lamps FL is directed directly into the processing chamber 6, and the other part is reflected by the reflector 52 and then directed into the processing chamber 6, and the semiconductor wafer W is flash-heated by the irradiation of these flash lights.

[0094] Flash heating is performed by irradiating a flash of light (flash of light) from flash lamps FL, which allows the surface temperature of the semiconductor wafer W to rise in a short time. That is, the flash of light irradiated from the flash lamps FL is an extremely short, intense flash of light with an irradiation time of approximately 0.1 milliseconds to 100 milliseconds, in which electrostatic energy previously stored in a capacitor is converted into an extremely short light pulse. The surface temperature of the semiconductor wafer W flash-heated by the irradiation of the flash of light from the flash lamps FL instantaneously rises to the processing temperature T2 and then rapidly drops.

[0095] In an oxidizing gas atmosphere, a semiconductor wafer W is heated to a preheating temperature T1 by light irradiation from a halogen lamp HL, and is then instantaneously heated to a processing temperature T2 by flash light irradiation from a flash lamp FL, causing a silicon oxide film to grow on the surface of the semiconductor wafer W.

[0096] After the flash heating process is completed, the halogen lamps HL are turned off after a predetermined time has elapsed. This causes the temperature of the semiconductor wafer W to rapidly decrease from the preheating temperature T1. The temperature of the semiconductor wafer W during this decrease is measured by the lower radiation thermometer 20, and the measurement result is transmitted to the control unit 3. The control unit 3 monitors, based on the measurement result of the lower radiation thermometer 20, whether the temperature of the semiconductor wafer W has decreased to a predetermined temperature. After the temperature of the semiconductor wafer W has decreased to or below the predetermined temperature, the pair of transfer arms 11 of the transfer mechanism 10 again move horizontally from the retracted position to the transfer operation position and rise, causing the lift pins 12 to protrude from the upper surface of the susceptor 74 and receive the heat-treated semiconductor wafer W from the susceptor 74. Next, the transfer opening 66, which had been closed by the gate valve 185, is opened, and the processed semiconductor wafer W placed on the lift pins 12 is transferred out by the transfer hand 151b (or transfer hand 151a) of the transfer robot 150. The transfer robot 150 advances the transfer hand 151b to a position directly below the semiconductor wafer W pushed up by the lift pins 12 and stops it. Then, the pair of transfer arms 11 descend, and the flash-heated semiconductor wafer W is handed over to and placed on the transfer hand 151b. Thereafter, the transfer robot 150 causes the transfer hand 151b to withdraw from the processing chamber 6, and the heat-treated semiconductor wafer W is transferred to the transfer chamber 170.

[0097] Next, the gate valve 132 opens, and the transfer robot 150 loads the heat-treated semiconductor wafer W into the cool chamber 131 of the cooling unit 130. The cooling unit 130 cools the semiconductor wafer W, which is at a relatively high temperature immediately after the heat treatment, to near room temperature (step S6). The cooling process of the semiconductor wafer W may also be performed in the cool chamber 141 of the cooling unit 140.

[0098] After the cooling process is completed, the transfer robot 150 transfers the cooled semiconductor wafer W from the cool chamber 131 to the transfer chamber 170. Then, the gate valve 302 opens, and the transfer robot 150 transfers the semiconductor wafer W into the film thickness measurement chamber 301. The film thickness measurement unit 300 measures the film thickness of the thin film formed on the surface of the semiconductor wafer W transferred into the film thickness measurement chamber 301 (step S7). In step S7, the film thickness measurement unit 300 measures the film thickness of the semiconductor wafer W after the heat treatment is performed in the heat treatment unit 160 and an oxide film is grown on it. The film thickness measurement result by the film thickness measurement unit 300 is transmitted to the control unit 3.

[0099] After the post-processing film thickness measurement is completed, the transfer robot 150 transfers the semiconductor wafer W from the film thickness measurement chamber 301 to the transfer chamber 170. Then, the gate valve 293 is opened and the transfer robot 150 transfers the semiconductor wafer W into the pass chamber 291 of the pass 290.

[0100] After the semiconductor wafer W is loaded into the pass chamber 291, the gate valve 293 is closed and the gate valve 292 is opened. Then, the delivery robot 120 removes the semiconductor wafer W from the pass chamber 291. The delivery robot 120 stores the semiconductor wafer W removed from the pass chamber 291 back into the carrier C (step S8). In this manner, the heat treatment of one semiconductor wafer W is completed.

[0101] The control unit 3 calculates the thickness of the oxide film grown on the surface of the semiconductor wafer W by the heat treatment in the heat treatment unit 160 by subtracting the film thickness before the heat treatment measured in step S3 from the film thickness after the heat treatment measured in step S7. Then, the control unit 3 adjusts the processing conditions for the heat treatment in the heat treatment unit 160 in accordance with the calculated film thickness (film thickness variation) (step S9). Specifically, a target film thickness is stored in advance in the memory unit of the control unit 3, and the control unit 3 compares the film thickness calculated from the actual measurement value with the target film thickness and adjusts the processing conditions for the preliminary heat treatment and / or flash heat treatment in the heat treatment unit 160 based on the comparison result.

[0102] In this embodiment, the control unit 3 adjusts the voltage applied to the flash lamps FL during flash heating in accordance with the calculated film thickness. More specifically, the control unit 3 adjusts the voltage charged to the capacitors that discharge the flash lamps FL. By adjusting the voltage applied to the flash lamps FL in accordance with the calculated film thickness, the thickness of the oxide film formed on the next semiconductor wafer W approaches the target film thickness. For example, as the number of times the flash lamps FL emit light increases, deterioration over time progresses, and the illuminance of the flash light gradually decreases. As a result, the thickness of the oxide film formed on the semiconductor wafer W by flash heating becomes thinner. Therefore, when the calculated film thickness is thinner than the target film thickness, the control unit 3 increases the voltage applied to the flash lamps FL to increase the illuminance of the flash light, thereby bringing the thickness of the oxide film formed on the semiconductor wafer W closer to the target film thickness.

[0103] In this embodiment, a film thickness measuring unit 300 that measures the film thickness of a thin film formed on a semiconductor wafer W is mounted inside the heat treatment apparatus 100. Therefore, when performing film thickness measurement, there is no need to transport the semiconductor wafer W to a film thickness measuring device separate from the heat treatment apparatus 100, and film thickness measurement can be performed within the heat treatment apparatus 100, allowing film thickness measurement to be performed efficiently.

[0104] Furthermore, film thickness measurements are taken before and after the heat treatment, the film thickness of the thin film grown by the heat treatment is calculated from the measurements, and the control unit 3 adjusts the conditions for the heat treatment in the heat treatment unit 160 according to the calculated film thickness. In other words, the control unit 3 automatically feeds back the film thickness measurement results to the conditions for the heat treatment, allowing the film thickness measurement results to be efficiently reflected in the heat treatment.

[0105] Although the embodiments of the present invention have been described above, various modifications other than those described above are possible without departing from the spirit of the present invention. For example, in the above embodiment, the control unit 3 adjusts the voltage applied to the flash lamps FL in accordance with the calculated film thickness. However, this is not limited to this. The control unit 3 may adjust the preheating temperature T1 at which the semiconductor wafer W is heated during preheating by light irradiation from the halogen lamps HL in accordance with the calculated film thickness. In other words, the control unit 3 may adjust the preheating temperature T1 by feedback control of the output of the halogen lamps HL in accordance with the calculated film thickness.

[0106] In addition, the control unit 3 may adjust other processing conditions, such as the power balance of the multiple halogen lamps HL, the concentration of the processing gas in the heat treatment space 65 in the processing chamber 6, or the flow rate of the processing gas supplied to the heat treatment space, depending on the calculated film thickness (film thickness variation).

[0107] It is also possible to create a map of film thickness distribution by measuring film thickness at multiple points on the surface of the semiconductor wafer W. When adjusting the power balance of multiple halogen lamps HL, it is preferable to determine the film thickness distribution on the surface of the semiconductor wafer W and make adjustments based on this.

[0108] In addition, in the above embodiment, oxygen gas is supplied to the heat treatment space 65 to form an oxide film on the semiconductor wafer W, but it is also possible to supply ozone gas to the heat treatment space 65 instead of oxygen gas and form an oxide film on the surface of the semiconductor wafer W by heat treatment.

[0109] Alternatively, a nitride film may be formed on the surface of the semiconductor wafer W by supplying ammonia to the heat treatment space 65 to form a nitriding atmosphere and performing heat treatment in the nitriding atmosphere. Alternatively, an amorphous silicon film formed on the surface of the semiconductor wafer W may be crystallized or a polysilicon film formed on the surface of the semiconductor wafer W may be modified by heat treatment using light irradiation from halogen lamps HL and flash lamps FL. Regardless of the film type, film thickness variations are calculated by measuring film thickness before and after heat treatment, and the control unit 3 adjusts the heat treatment conditions in the heat treatment unit 160 according to the film thickness variations, thereby efficiently reflecting the film thickness measurement results in the heat treatment.

[0110] Furthermore, in the above embodiment, the flash lamp house 5 is provided with 30 flash lamps FL, but this is not limited to this and the number of flash lamps FL can be any number. Furthermore, the flash lamps FL are not limited to xenon flash lamps and may be krypton flash lamps. Furthermore, the number of halogen lamps HL provided in the halogen lamp house 4 is not limited to 40 and can be any number.

[0111] Furthermore, in the above embodiment, the semiconductor wafer W is preheated using a filament-type halogen lamp HL as a continuously lit lamp that emits light continuously for one second or more, but this is not limited to this, and preheating may be performed using a discharge arc lamp (e.g., a xenon arc lamp) or an LED lamp as a continuously lit lamp instead of the halogen lamp HL.

[0112] Furthermore, the substrate to be processed by the heat treatment apparatus 100 is not limited to a semiconductor wafer, but may be a glass substrate used in a flat panel display such as a liquid crystal display device, or a substrate for a solar cell. [Explanation of symbols]

[0113] 3. Control Unit 4 Halogen lamp house 5. Flash Lamp House 6 Processing Chambers 7 Holding part 10 Transfer mechanism 65 Heat Treatment Space 74 Susceptor 100 Heat treatment device 110 Indexer section 111 Loading Port 120 Delivery Robot 130,140 Cooling section 150 Transport Robot 160 Heat Treatment Section 300 Film Thickness Measurement Unit 310 Optical Unit 400 Inspection Department C Carrier FL flash lamp HL halogen lamp W Semiconductor wafer

Claims

1. A heat treatment method for heating a substrate by irradiating the substrate with flash light, comprising: a film thickness measurement step of measuring a film thickness of the thin film formed on the substrate; a preheating step of irradiating the substrate with light from a continuously lit lamp to heat the substrate; a flash heating step of irradiating the substrate with flash light from a flash lamp to heat the substrate; Equipped with The film thickness measuring step includes: a first film thickness measuring step of measuring a film thickness before the preheating step and the flash heating step are performed; a second film thickness measuring step of measuring a film thickness after the preheating step and the flash heating step are performed; Including, a heat treatment method characterized in that processing conditions in the preheating step and the flash heating step are adjusted in accordance with a film thickness variation, which is the difference between the film thickness measured in the first film thickness measurement step and the film thickness measured in the second film thickness measurement step.

2. In the heat treatment method according to claim 1, a heat treatment method, characterized in that a voltage applied to the flash lamp is adjusted in the flash heating step in accordance with the film thickness measured in the film thickness measuring step;

3. In the heat treatment method according to claim 1, a preheating temperature for heating the substrate in the preheating step being adjusted in accordance with the film thickness measured in the film thickness measuring step;

4. A heat treatment apparatus for heating a substrate by irradiating the substrate with flash light, a film thickness measuring unit for measuring the film thickness of the thin film formed on the substrate; a heat treatment section for performing heat treatment on the substrate; Equipped with The heat treatment section a continuously lit lamp that irradiates light onto the substrate to heat the substrate; a flash lamp that irradiates the substrate with flash light to heat the substrate; and the film thickness measuring unit measures a film thickness before the heat processing unit performs a heat treatment on the substrate, and measures a film thickness after the heat processing unit performs a heat treatment on the substrate, A heat treatment apparatus characterized in that processing conditions in the heat treatment section are adjusted in response to a film thickness variation, which is the difference between a film thickness measured before the heat treatment and a film thickness measured after the heat treatment.

5. In the heat treatment device according to claim 4, 10. A heat treatment apparatus comprising: a film thickness measuring unit that adjusts a voltage applied to the flash lamp in accordance with the film thickness measured by the film thickness measuring unit;

6. In the heat treatment device according to claim 4, a preheating temperature for heating the substrate by light irradiation from the continuously lit lamp in accordance with the film thickness measured by the film thickness measuring unit;

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