JP2005207997A - Substrate processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate processing apparatus capable of measuring the temperature of a substrate heated by radiating flashing light from a flash lamp. <P>SOLUTION: This substrate processing apparatus comprises a heat treatment part for lighting a xenon flash lamp to perform flash heating, and an alignment part for turning the direction of a semiconductor wafer to a fixed direction before heating. The alignment part includes a reflectance measuring mechanism to measure the reflectance of the surface of the semiconductor wafer of a processing object prior to carrying into the heat treatment part. When the flash heating of the semiconductor wafer is performed in the heat treatment part, the emitted light from the wafer surface by heat radiation is collected to measure the radiant intensity thereof. The instantaneous highest temperature of the semiconductor wafer is calculated from the reflectance measured before the heat treatment and the radiant intensity measured in the flash heating. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a heat treatment apparatus for heat-treating a semiconductor wafer, a glass substrate or the like (hereinafter simply referred to as “substrate”) by flashing the substrate, and more particularly to a substrate processing apparatus for measuring the temperature of the substrate during flash irradiation. About.

  Conventionally, in an ion activation process of a semiconductor wafer after ion implantation, a heat treatment apparatus such as a lamp annealing apparatus using a halogen lamp has been used. In such a heat treatment apparatus, the semiconductor wafer is ion-activated by heating (annealing) the semiconductor wafer to a temperature of about 1000 ° C. to 1100 ° C., for example. In such a heat treatment apparatus, the temperature of the substrate is raised at a rate of several hundred degrees per second by using the energy of light irradiated from the halogen lamp.

  In such a lamp annealing apparatus using a halogen lamp, for example, Patent Document 1 discloses a technique for measuring a wafer temperature during heat treatment in a non-contact manner using a radiation thermometer installed on the back side of a semiconductor wafer. . In the technique described in Patent Document 1, two types of effective reflectivity are created by a rotary sector, and a predetermined calculation is performed based on the result of measuring the radiation intensity corresponding to the two types of effective reflectivity during heat treatment. The temperature of the semiconductor wafer is calculated.

  On the other hand, in recent years, as semiconductor devices have been highly integrated, it is desired to reduce the junction depth as the gate length becomes shorter. However, even when ion activation of a semiconductor wafer is performed using the above-described lamp annealing apparatus that raises the temperature of the substrate at a rate of several hundred degrees per second, ions such as boron and phosphorus implanted in the semiconductor wafer are heated by heat. It has been found that the phenomenon of deep diffusion occurs. When such a phenomenon occurs, there is a concern that the junction depth becomes deeper than required, which hinders good device formation.

  To solve such problems, the surface of the semiconductor wafer is irradiated with flash light using a xenon flash lamp or the like, so that only the surface of the semiconductor wafer into which ions have been implanted is made extremely short (less than several milliseconds). Techniques for raising the temperature have been proposed (see, for example, Patent Documents 2 and 3). The radiation spectral distribution of a xenon flash lamp ranges from the ultraviolet region to the near infrared region, has a shorter wavelength than the conventional halogen lamp, and almost coincides with the fundamental absorption band of a silicon semiconductor wafer. Therefore, when the semiconductor wafer is irradiated with flash light from the xenon flash lamp, the semiconductor wafer can be rapidly heated with little transmitted light. It has also been found that if the flash irradiation is performed for a very short time of several milliseconds or less, only the vicinity of the surface of the semiconductor wafer can be selectively heated. For this reason, if the temperature is raised for a very short time by a xenon flash lamp, only the ion activation can be performed without diffusing ions deeply.

Japanese Patent Laid-Open No. 11-258051 JP 59-169125 A JP 63-166219 A

  However, it is extremely difficult to measure the wafer temperature during the heat treatment even if a temperature measuring technique in a lamp annealing apparatus using a conventional halogen lamp is applied to a heat treatment apparatus using a xenon flash lamp. The reason is that the temperature is first limited to the vicinity of the wafer surface, and even if a radiation thermometer is installed on the back side of the wafer, the instantaneous maximum temperature on the front side cannot be measured. It is impossible to install a radiation thermometer on the front side of the wafer because it directly receives the intense flash from the xenon flash lamp. Further, it takes a certain amount of time to produce two types of effective reflectivity by the rotary sector as disclosed in Patent Document 1, but this time is longer than the wafer heating time by flash irradiation from the xenon flash lamp. For this reason, the maximum instantaneous temperature of the wafer cannot be measured accurately.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a substrate processing apparatus capable of measuring the temperature of a substrate heated by irradiation with flash light from a flash lamp.

  In order to solve the above-mentioned problem, the invention of claim 1 is a substrate processing apparatus for heating a substrate by irradiating flash light on the substrate, and a heat treatment chamber for accommodating the substrate and performing heat treatment; A flash lamp that irradiates a surface of a substrate accommodated in the heat treatment chamber with flash light; a reflectance measuring means that measures the reflectance of the surface of the substrate to be processed before the flash light is irradiated from the flash lamp; and Radiation intensity measuring means for measuring the radiation intensity of thermal radiation from the surface of the substrate to be processed which is heated by being irradiated with flash light from a flash lamp, and the reflectance measured by the reflectance measuring means and the radiation intensity measuring means Temperature calculating means for calculating the temperature of the substrate to be processed from the radiation intensity measured by

  Further, the invention of claim 2 is the substrate processing apparatus according to the invention of claim 1, wherein the reflectance measuring means measures the reflectance of light having a wavelength of 2 μm or more, and the radiation intensity measuring means The radiation intensity of the light having the predetermined wavelength is measured.

  Further, the invention of claim 3 is the substrate processing apparatus according to the invention of claim 1, wherein the reflectance measuring means measures the reflectance of each of the light having the wavelength of 2 μm or more and the first wavelength and the second wavelength, The radiation intensity measuring unit measures the radiation intensity of each of the first wavelength light and the second wavelength light, and the temperature calculation unit causes the first wavelength light reflectance and the second wavelength light reflectance to be measured. The temperature of the substrate to be processed is calculated from the emissivity ratio determined from the above and the radiation intensity ratio between the radiation intensity of the first wavelength light and the radiation intensity of the second wavelength light.

  Further, the invention of claim 4 is the substrate processing apparatus according to any one of claims 1 to 3, wherein the substrate is disposed between the processing target substrate accommodated in the heat treatment chamber and the flash lamp, A quartz rod is further provided for guiding thermal radiation from the surface of the substrate to be processed to the radiation intensity measuring means.

  According to a fifth aspect of the present invention, in the substrate processing apparatus according to the fourth aspect of the present invention, the light shielding member that shields light between the quartz rod and the radiation intensity measuring means, and the thermal radiation from the processing target substrate Moving means for moving the light shielding member so as to switch between a measurement state incident on the radiation intensity measuring means and a non-measurement state where the thermal radiation is shielded, and the moving means includes flash light from the flash lamp. The light-shielding member is moved so as to be in the measurement state immediately before irradiation is performed.

  According to a sixth aspect of the present invention, in the substrate processing apparatus according to any one of the first to fifth aspects, the surface of the substrate to be processed is substantially the same as the reflectance measuring means and the radiation intensity measuring means. The reflectance and radiation intensity at each position are measured.

  The invention according to claim 7 is the substrate processing apparatus according to any one of claims 1 to 6, further comprising an indexer unit for carrying an unprocessed substrate into the apparatus, wherein the reflectance measuring means Is disposed on the substrate transfer path from the indexer to the heat treatment chamber.

  The invention according to claim 8 is the substrate processing apparatus according to claim 7, further comprising an alignment unit that directs the direction of the unprocessed substrate in a certain direction, and the reflectance measuring means is arranged in the alignment unit. Yes.

  According to the first aspect of the present invention, the reflectance of the surface of the processing target substrate measured in advance before the flash light irradiation from the flash lamp is performed, and the surface of the processing target substrate heated by the flash light irradiation from the flash lamp. Since the temperature of the substrate to be processed is calculated based on the radiation intensity of the thermal radiation, it is possible to measure the temperature of the substrate heated in a very short time by irradiating flash light from a flash lamp.

  According to the invention of claim 2, the reflectance measuring means measures the reflectance of light having a predetermined wavelength of 2 μm or more, and the radiation intensity measuring means measures the radiation intensity of the light having the predetermined wavelength. Measurement can be performed outside the wavelength range of the flash lamp, and the measurement is performed with a single color having a fast response speed, which is suitable for measuring the temperature of the substrate by flash heating.

  According to the invention of claim 3, the reflectance measuring means measures the reflectance of each of the first wavelength and the second wavelength having a wavelength of 2 μm or more, and the radiation intensity measuring means is the first wavelength and the second wavelength. The temperature calculation means measures the radiation intensity of each of the light beams of the first wavelength, and the temperature ratio calculating means obtains the radiation ratio of the first wavelength light from the reflectance of the first wavelength and the second wavelength light. Since the temperature of the substrate to be processed is calculated from the ratio of the radiant intensity to the radiant intensity of the light of the wavelength, the measurement can be performed outside the wavelength range of the flash lamp, and it is measured in two colors, Suitable for temperature measurement of substrates with large temperature dependence.

  According to the invention of claim 4, since the quartz rod for guiding the heat radiation from the surface of the substrate to be processed to the radiation intensity measuring means is disposed between the substrate to be processed and the flash lamp, heating by flash irradiation is performed. The temperature of the surface of the substrate to be processed can be measured without hindering the processing.

  According to the invention of claim 5, the light shielding member is moved so as to be in a measurement state in which the heat radiation from the substrate to be processed enters the radiation intensity measuring means immediately before the flash light irradiation from the flash lamp is performed. Therefore, the influence of the zero point drift of the radiation intensity measuring means can be suppressed, and the instantaneous maximum intensity of thermal radiation can be accurately measured.

  According to the invention of claim 6, since the reflectance and the radiation intensity are measured at substantially the same position on the surface of the substrate to be processed, more accurate temperature measurement can be performed.

  According to the seventh aspect of the present invention, since the reflectance measuring means is disposed on the substrate transportation system path from the indexer section to the heat treatment chamber, the reflectance is being measured during normal substrate transportation. Measurements can be made and good processing efficiency is obtained.

  According to the invention of claim 8, since the reflectance measuring means is arranged in the alignment section, the reflectance measurement can be performed when alignment is performed in which the direction of the unprocessed substrate is directed in a certain direction. Good processing efficiency can be obtained.

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

<1. First Embodiment>
<1-1. Overall configuration of substrate processing apparatus>
FIG. 1 is a plan view showing a substrate processing apparatus 100 according to the present invention, and FIG. 2 is a front view. 1 and FIG. 2 are partly cross-sectional views as appropriate, and details are simplified as appropriate. Further, in FIGS. 1 and 2, an XYZ orthogonal coordinate system in which the Z-axis direction is a vertical direction and the XY plane is a horizontal plane is attached as necessary to clarify the directional relationship.

  As shown in FIGS. 1 and 2, the substrate processing apparatus 100 includes an indexer unit 110 and an indexer unit 110 for loading an unprocessed semiconductor wafer W into the apparatus and unloading the processed semiconductor wafer W outside the apparatus. On the other hand, the delivery robot 120 that takes in and out the semiconductor wafer W, the alignment unit 130 that positions the unprocessed semiconductor wafer W, the cooling unit (cooler) 140 that cools the processed semiconductor wafer W, the alignment unit 130, and the cooling unit A transfer robot 150 that takes in and out the semiconductor wafer W with respect to 140 and the like, and a heat treatment unit 160 that performs flash heat treatment on the semiconductor wafer W are included.

  In addition, a transfer chamber 170 that houses the transfer robot 150 is provided as a transfer space for the semiconductor wafer W by the transfer robot 150, and the alignment unit 130, the cooling unit 140, and the heat treatment unit 160 are connected to the transfer chamber 170. ing.

  The indexer unit 110 is a part on which two carriers 91 are transported and placed by an automatic guided vehicle (AGV) or the like, and the semiconductor wafer W is carried into and out of the substrate processing apparatus 100 while being accommodated in the carrier 91. The Further, the indexer unit 110 is configured such that the carrier 91 is moved up and down as indicated by an arrow 91U so that an arbitrary semiconductor wafer W can be taken in and out by the delivery robot 120.

  The delivery robot 120 is slidable as indicated by an arrow 120S and is rotatable as indicated by an arrow 120R. With this, the semiconductor wafer W is taken in and out of the two carriers 91. Further, the semiconductor wafer W is delivered to the alignment unit 130 and the cooling unit 140.

  In addition, the semiconductor wafer W is put in and out of the carrier 91 by the delivery robot 120 by the sliding movement of the hand 121 and the raising and lowering movement of the carrier 91. In addition, the semiconductor wafer W is transferred between the delivery robot 120 and the alignment unit 130 or the cooling unit 140 by sliding the hand 121 and a semiconductor wafer by a pin (a pin that pushes up the semiconductor wafer W in the alignment unit 130 or the cooling unit 140). This is done by moving W up and down.

  The semiconductor wafer W is delivered from the delivery robot 120 to the alignment unit 130 so that the center of the semiconductor wafer W is located at a predetermined position. Then, the alignment unit 130 rotates the semiconductor wafer W to direct the semiconductor wafer W in an appropriate direction. Further, the alignment unit 130 includes a reflectance measurement mechanism, and measures the reflectance at a predetermined position on the surface of the semiconductor wafer W. The alignment unit 130 will be further described later.

  The transfer robot 150 is turnable as indicated by an arrow 150R about a vertical axis, and has two link mechanisms composed of a plurality of arm segments, and a semiconductor is provided at each end of the two link mechanisms. Transfer arms 151 a and 151 b for holding the wafer W are provided. These transfer arms 151a and 151b are arranged vertically apart from each other by a predetermined pitch, and can be slid linearly in the same horizontal direction independently by a link mechanism. Further, the transfer robot 150 moves up and down the two transfer arms 151a and 151b while moving away from each other by a predetermined pitch by moving up and down a base provided with two link mechanisms.

  When the transfer robot 150 transfers (inserts / removes) the semiconductor wafer W as a transfer partner to the alignment unit 130, the heat processing unit 160, or the cooling unit 140, first, the transfer arms 151a and 151b are opposed to the transfer partner. It turns and then moves up and down (or while it is turning) so that one of the transfer arms is positioned at a height at which the semiconductor wafer W is delivered to the delivery partner. Then, the transfer arm 151a (151b) is slid linearly in the horizontal direction to deliver the semiconductor wafer W.

  The heat treatment unit 160 is a part that performs heat treatment by irradiating the semiconductor wafer W with flash light from a xenon flash lamp 69 (hereinafter also simply referred to as “flash lamp 69”). The heat treatment unit 160 will also be described in detail later.

  Since the temperature of the semiconductor wafer W immediately after being processed by the heat processing unit 160 is high, the semiconductor wafer W is placed on the cooling unit 140 and cooled by the transfer robot 150. The semiconductor wafer W cooled by the cooling unit 140 is returned to the carrier 91 by the delivery robot 120 as a processed semiconductor wafer W.

  Further, as described above, in the substrate processing apparatus 100, the periphery of the transfer robot 150 is covered with the transfer chamber 170, and the alignment unit 130, the cooling unit 140, and the heat processing unit 160 are connected to the transfer chamber 170. Gate valves 181 and 182 are respectively provided between the delivery robot 120 and the alignment unit 130 and the cooling unit 140, and gate valves are respectively provided between the transfer chamber 170 and the alignment unit 130, the cooling unit 140 and the heat treatment unit 160. 183, 184, 185 are provided. Then, a high-purity nitrogen gas is supplied from a nitrogen gas supply unit (not shown) so that the inside of the alignment unit 130, the cooling unit 140, and the transfer chamber 170 is kept clean, and excess nitrogen gas is appropriately exhausted. Exhausted from the tube. Note that these gate valves are appropriately opened and closed when the semiconductor wafer W is transferred.

  The alignment unit 130 and the cooling unit 140 are located at different positions between the delivery robot 120 and the transfer robot 150, and the alignment unit 130 temporarily places the semiconductor wafer W to position the semiconductor wafer W. In the cooling unit 140, the semiconductor wafer W is temporarily placed in order to cool the processed semiconductor wafer W.

<1-2. Configuration of alignment unit>
FIG. 3 is a side sectional view showing a schematic configuration of the alignment unit 130. The alignment unit 130 includes an alignment head 132 and a wafer stage 133 inside the alignment chamber 131. The alignment chamber 131 is formed with an opening through which the semiconductor wafer W is delivered from the delivery robot 120 and an opening through which the transfer robot 150 carries out the semiconductor wafer W, and gate valves 181 and 183 are provided in the respective openings. ing. When the gate valves 181 and 183 are closed, the inside of the alignment chamber 131 becomes a sealed space.

  The alignment head 132 includes a sensor composed of a pair of light projecting portions and light receiving portions, and detects the notch of the semiconductor wafer W by the sensor (in the case of a semiconductor wafer W of φ300 mm). Note that an orientation flat for alignment is formed on the semiconductor wafer W having a diameter of 200 mm, and the sensor of the alignment head 132 detects the orientation flat.

  Pins 134 are erected on the wafer stage 133. The pins 134 can be moved up and down with respect to the wafer stage 133 by a lifting mechanism (not shown). The pins 134 may be fixed to the wafer stage 133 and the wafer stage 133 itself may be moved up and down. Further, the wafer stage 133 is rotated around the axis along the vertical direction by the motor 135, and the pins 134 are also rotated accordingly.

  Further, the alignment unit 130 is provided with a reflectance measurement mechanism 230 for measuring the reflectance of the surface of the semiconductor wafer W. The reflectance measurement mechanism 230 includes a light projecting unit 231, a light receiving unit 232, and a detection unit 235. The light projecting unit 231 and the light receiving unit 232 are attached to the reflecting mirror 233. The reflecting mirror 233 is a dome-shaped concave mirror and is installed on the ceiling portion of the alignment chamber 131. The inner surface of the reflecting mirror 233 is a mirror surface, and the dome shape may be, for example, a hemisphere or an ellipsoid.

  A light source 236 is built in the light projecting unit 231. As the light source 236, for example, a halogen lamp having a radiation distribution from visible light to infrared light is used. The light source 236 is connected to a power supply circuit (not shown). On the other hand, the light receiving unit 232 includes a quartz rod 237 and a condenser lens 238. In order to prevent light from the light projecting unit 231 from directly entering the light receiving unit 232, the light source 236 of the light projecting unit 231, the quartz rod 237 of the light receiving unit 232, and the condenser lens 238 are each covered with a cylindrical cover. ing.

  In addition, the angle formed by the lamp axis of the light source 236 and the angle formed by the central axis of the quartz rod 237 with respect to the normal line of the surface of the semiconductor wafer W supported by the pins 134 are set to the same angle. Further, the light projection unit 231 and the light receiving unit 232 are installed as close to the top of the reflecting mirror 233 as possible so that the angle is as small as possible (preferably 45 ° or less), and the direct light from the light projecting unit 231 is received by the light receiving unit. It is difficult for the light to enter the H.232. By doing so, the light receiving unit 232 is positioned on the path of the reflected light emitted from the light source 236 of the light projecting unit 231 and reflected on the surface of the semiconductor wafer W, and only the reflected light is efficiently collected. Can be light. The reflected light is incident on the quartz rod 237 of the light receiving unit 232, is collected by the condenser lens 238, is incident on the end surface of the optical fiber 234, and is guided to the detection unit 235.

  What is important when measuring the reflectance of the semiconductor wafer W is that only the reflected light reflected by the surface of the semiconductor wafer W is received by the light receiving unit 232 so that ambient light and direct light from the light projecting unit 231 do not enter. That is. Therefore, the light source 236, the quartz rod 237, and the condenser lens 238 are covered with a cylindrical cover, and the mounting positions of the light projecting unit 231 and the light receiving unit 232 are adjusted as described above. In addition, it is preferable to apply an antireflection treatment to the inner wall surface of the alignment chamber 131 so that the light emitted from the light projecting unit 231 is reflected by the inner wall of the alignment chamber 131 and does not enter the light receiving unit 232. Further, in order to perform stable reflectance measurement, it is preferable to provide a constant power source control system in the power source circuit of the light source 236 so that the intensity of the emitted light from the light projecting unit 231 is constant.

  The main role of the reflecting mirror 233 is to prevent ambient light from entering the light receiving unit 232. Therefore, the inner surface of the reflecting mirror 233 is not necessarily a mirror surface. In addition, if the alignment chamber 131 can reliably prevent disturbance light from entering the light receiving unit 232, the reflecting mirror 233 is unnecessary, and the light projecting unit 231 and the light receiving unit 232 are directly connected to the ceiling portion of the alignment chamber 131. It may be fixed.

  The detection unit 235 is attached to the alignment unit 130 and includes a rotating chopper 239, a filter 240, a detection element 241, and a reflectance calculation unit 243. FIG. 4 is a plan view of the rotating chopper 239. The rotary chopper 239 is configured by attaching two fan blades 239b at opposing positions around the disk-shaped member 239a. The fan blade 239b can block the reflected light of the light source 236, and the central angle is 90 °. Accordingly, a region where the reflected light of the light source 236 is transmitted and a region where light is shielded are formed around the disk-shaped member 239a every 90 ° along the circumferential direction. The rotating chopper 239 is rotated around an axis along the vertical direction by a motor 242. Then, each time the rotating chopper 239 rotates by 90 °, the rotating chopper 239 is installed so that the state where the light guided by the optical fiber 234 enters the detection element 241 and the state where the light is blocked are switched. ing.

  Returning to FIG. 3, the filter 240 is an optical filter that selectively transmits light having a wavelength of 2 μm or more. The detection element 241 is, for example, a lead sulfide (PbS) element, and measures the intensity of received light using the photoelectric effect. Lead sulfide has a large photoelectric effect in the infrared region of 2 μm or more which is outside the wavelength range of the flash light of the xenon flash lamp, and the detection element 241 is suitable for detecting light in the infrared region of 2 μm or more.

  The reflectance calculation unit 243 is electrically connected to the detection element 241 and calculates the reflectance of the surface of the semiconductor wafer W based on the output signal of the detection element 241 that has received the light guided by the optical fiber 234. It is an arithmetic circuit. Note that the reflectance calculation unit 243 may be configured by a computer including a CPU or the like, and cause the CPU to execute a program for calculating the reflectance. The reflectance of the semiconductor wafer W calculated by the reflectance calculation unit 243 is transmitted to the temperature measuring mechanism 260 of the heat processing unit 160 described later.

  When the semiconductor wafer W is transferred from the delivery robot 120 to the alignment unit 130, the gate valve 181 is opened, the hand 121 holding the semiconductor wafer W enters the alignment chamber 131, and the center of the semiconductor wafer W is the center of the wafer stage 133. Stop at the position just above. Then, the pins 134 rise and receive the semiconductor wafer W from the hand 121. Thereafter, the hand 121 is withdrawn from the alignment chamber 131 and the gate valve 181 is closed. Subsequently, the pins 134 are lowered so that the semiconductor wafer W is positioned at a predetermined height position. At this time, the semiconductor wafer W is not in direct contact with the wafer stage 133, and the semiconductor wafer W is always supported by the pins 134.

  The motor 135 starts rotating in a state where the semiconductor wafer W is supported by the pins 134 at a predetermined height position. In conjunction with the rotation of the motor 135, the wafer stage 133 and the pins 134 also rotate, and the semiconductor wafer W supported by the pins 134 also rotates accordingly. When the alignment head 132 detects the notch (or orientation flat) of the semiconductor wafer W, the motor 135 stops rotating. As a result, the semiconductor wafer W is directed in a certain direction. After the semiconductor wafer W stops in a certain direction, the reflectance measurement mechanism 230 measures the reflectance at a predetermined position on the surface of the semiconductor wafer W. The reflectance calculation method will be further described later.

  After the measurement of the reflectance of the semiconductor wafer W is completed, the gate valve 183 is opened and the pin 134 is raised. Subsequently, the transfer arm 151 a (151 b) of the transfer robot 150 enters the alignment chamber 131 and stops immediately below the semiconductor wafer W. Then, the pins 134 are lowered, and the transfer arm 151a (151b) receives the semiconductor wafer W and exits from the alignment chamber 131. In this way, the transfer of the semiconductor wafer W from the alignment unit 130 by the transfer robot 150 is completed.

<1-3. Configuration of heat treatment unit>
Next, the configuration of the heat treatment unit 160 will be further described. 5 and 6 are side sectional views showing the heat treatment unit 160. In the heat treatment unit 160, flash heating of a substrate such as a semiconductor wafer W is performed.

  The heat treatment unit 160 includes a light transmitting plate 61, a bottom plate 62, and a cylindrical side plate 63 (64), and includes a chamber 65 for accommodating the semiconductor wafer W and performing heat treatment therein. The translucent plate 61 constituting the upper part of the chamber 65 is made of a material having optical transparency such as quartz, for example, and serves as a chamber window that transmits light emitted from the flash lamp 69 and guides it into the chamber 65. It is functioning. Further, on the bottom plate 62 constituting the chamber 65, support pins 70 are provided so as to pass through holding means including a wafer support member 73 and a heating plate 74, which will be described later, and support the semiconductor wafer W from its lower surface. .

  Further, an opening 66 for carrying in and out the semiconductor wafer W is formed in the side plate 64 constituting the chamber 65. The opening 66 can be opened and closed by a gate valve 68 that rotates about a shaft 67. The semiconductor wafer W is loaded into the chamber 65 by the transfer robot 150 with the opening 66 being opened. Further, when the semiconductor wafer W is heat-treated in the chamber 65, the opening 66 is closed by the gate valve 68.

  The chamber 65 is provided below the light source 5. The light source 5 includes a plurality of (30 in this embodiment) flash lamps 69 and a reflector 71. The plurality of flash lamps 69 are rod-shaped lamps each having a long cylindrical shape, and are arranged in parallel with each other such that the longitudinal direction thereof is along the horizontal direction. The reflector 71 is disposed above the plurality of flash lamps 69 so as to cover them entirely.

  The xenon flash lamp 69 includes a glass tube in which xenon gas is sealed and an anode and a cathode connected to a capacitor at both ends thereof, and a trigger electrode wound around an external portion of the glass tube. Prepare. Since xenon gas is an electrical insulator, electricity does not flow into the glass tube under normal conditions. However, if the insulation is broken by applying a high voltage to the trigger electrode, the electricity stored in the capacitor instantaneously flows into the glass tube, and the xenon gas is heated by Joule heat at that time, and light is emitted. . In the xenon flash lamp 69, the electrostatic energy stored in advance is converted into an extremely short light pulse of 0.1 millisecond to 10 millisecond. It has the feature that it can. Instead of the xenon flash lamp 69, a flash lamp filled with other rare gas, for example, a krypton flash lamp may be used.

  A light diffusing plate 72 is disposed between the light source 5 and the translucent plate 61. As this light diffusion plate 72, a surface of quartz glass as a light transmitting material subjected to light diffusion processing is used. Instead of using the light diffusing plate 72, the translucent plate 61 may be subjected to surface processing for light diffusion.

  Part of the light emitted from the flash lamp 69 passes directly through the light diffusing plate 72 and the light transmitting plate 61 toward the chamber 65. Further, another part of the light emitted from the flash lamp 69 is once reflected by the reflector 71, then passes through the light diffusing plate 72 and the light transmitting plate 61 and goes into the chamber 65.

  A heating plate 74 and a wafer support member (susceptor) 73 that holds the semiconductor wafer W are provided in the chamber 65. The wafer support member 73 is installed on the upper surface of the heating plate 74. Further, a position shift prevention pin 75 of the semiconductor wafer W is attached to the surface of the wafer support member 73.

  The heating plate 74 is for preheating (assist heating) the semiconductor wafer W. The heating plate 74 is made of aluminum nitride and has a configuration in which a heater and a sensor for controlling the heater are housed. On the other hand, the wafer support member 73 diffuses the heat energy from the heating plate 74 and uniformly preheats the semiconductor wafer W. As a material of the wafer support member 73, high-purity ceramics or quartz is adopted. Note that the wafer support member 73 may be made of aluminum nitride in the same manner as the heating plate 74.

  The wafer support member 73 and the heating plate 74 are configured to move up and down between the loading / unloading position of the semiconductor wafer W shown in FIG. 5 and the heat treatment position of the semiconductor wafer W shown in FIG. .

  That is, the heating plate 74 is connected to the moving plate 42 via the cylindrical body 41. The moving plate 42 can be moved up and down by being guided by a guide member 43 supported by a bottom plate 62 of the chamber 65. A fixed plate 44 is fixed to the lower end portion of the guide member 43, and a motor 40 that rotationally drives a ball screw 45 is disposed at the central portion of the fixed plate 44. The ball screw 45 is screwed with a nut 48 connected to the moving plate 42 via connecting members 46 and 47. Therefore, the wafer support member 73 and the heating plate 74 can be moved up and down between the loading / unloading position of the semiconductor wafer W shown in FIG. 5 and the heat treatment position of the semiconductor wafer W shown in FIG. it can.

  The semiconductor wafer W shown in FIG. 5 is loaded or unloaded by placing the semiconductor wafer W carried in from the opening 66 using the transfer robot 150 on the support pins 70 or on the support pins 70. The wafer support member 73 and the heating plate 74 are lowered so that the semiconductor wafer W can be unloaded from the opening 66. In this state, the upper ends of the support pins 70 pass through the through holes formed in the wafer support member 73 and the heating plate 74 and protrude upward from the surface of the wafer support member 73.

  On the other hand, the heat treatment position of the semiconductor wafer W shown in FIG. 6 is a position where the wafer support member 73 and the heating plate 74 are raised above the upper ends of the support pins 70 in order to perform heat treatment on the semiconductor wafer W. In the process in which the wafer support member 73 and the heating plate 74 are raised from the carry-in / carry-out position of FIG. 5 to the heat treatment position of FIG. 6, the semiconductor wafer W placed on the support pins 70 is received by the wafer support member 73 and its lower surface. Is supported and supported by the surface of the wafer support member 73 and held in a horizontal position at a position in the chamber 65 close to the translucent plate 61. Conversely, in the process in which the wafer support member 73 and the heating plate 74 are lowered from the heat treatment position to the carry-in / carry-out position, the semiconductor wafer W supported by the wafer support member 73 is transferred to the support pins 70.

  In a state where the wafer support member 73 and the heating plate 74 that support the semiconductor wafer W are raised to the heat treatment position, the translucent plate 61 is positioned between the semiconductor wafer W held by them and the light source 5. Note that the distance between the wafer support member 73 and the light source 5 at this time can be adjusted to an arbitrary value by controlling the rotation amount of the motor 40.

  Further, between the bottom plate 62 of the chamber 65 and the moving plate 42, a telescopic bellows 77 is disposed so as to surround the cylindrical body 41 and maintain the chamber 65 in an airtight body. When the wafer support member 73 and the heating plate 74 are raised to the heat treatment position, the bellows 77 contracts, and when the wafer support member 73 and the heating plate 74 are lowered to the loading / unloading position, the bellows 77 is expanded and the atmosphere in the chamber 65 is increased. Shut off from outside atmosphere.

  In the side plate 63 opposite to the opening 66 in the chamber 65, an introduction path 78 connected to the on-off valve 80 is formed. The introduction path 78 is for introducing a gas necessary for processing, for example, an inert nitrogen gas, into the chamber 65. On the other hand, a discharge passage 79 connected to the on-off valve 81 is formed in the opening 66 in the side plate 64. The discharge path 79 is for discharging the gas in the chamber 65, and is connected to an exhaust means (not shown) via the on-off valve 81.

  Further, the heat treatment unit 160 is provided with a temperature measuring mechanism 260 that measures the temperature of the semiconductor wafer W when the flash light is irradiated from the flash lamp 69 and the semiconductor wafer W is heated. FIG. 7 is a diagram showing a configuration of the temperature measuring mechanism 260. The temperature measuring mechanism 260 includes a daylighting unit 261 and a measuring unit 262 as main components.

  The daylighting unit 261 includes a quartz rod 264, a connector 265, and a condenser lens 266. The quartz rod 264 is a quartz cylindrical member, and in this example, the diameter is 3 mm. The tip of the quartz rod 264 is cut so that the normal of the cut surface forms an angle of 45 ° with the central axis of the quartz rod 264. On the other hand, the base end of the quartz rod 264 is inserted into the connector 265. Note that the base end portion of the quartz rod 264 is cut perpendicular to the center axis of the rod. A condensing lens 266 is disposed in the connector 265 so as to face the base end of the quartz rod 264. For example, one end of an optical fiber 263 having a diameter of 0.4 mm is connected to the side of the connector 265 opposite to the side where the quartz rod 264 is inserted.

  In the side plate 64 of the chamber 65, a fine hole 64a into which the quartz rod 264 can be freely inserted is formed in the horizontal direction. A connector 265 can be mounted around the pore 64 a on the outer wall of the side plate 64. By attaching the connector 265 with the quartz rod 264 inserted to the outer wall of the side plate 64, the quartz rod 264 passes through the hole 64a, and the tip of the quartz rod 264 penetrates the semiconductor wafer W supported by the wafer support member 73. It reaches between the optical plate 61. Even when the wafer support member 73 and the heating plate 74 are raised to the heat treatment position, the pores 64a are formed at positions where the semiconductor wafer W supported by them and the quartz rod 264 do not interfere with each other. Yes. Accordingly, the quartz rod 264 is arranged with its central axis along the horizontal direction between the surface of the semiconductor wafer W to be processed which has been raised to the heat treatment position by the wafer support member 73 and the heating plate 74 and the flash lamp 69. (See FIG. 6).

  The heat radiation light from the semiconductor wafer W is guided through the quartz rod 264 and is collected by the condenser lens 266 so as to enter the end face of the optical fiber 263. Light incident on the end face of the optical fiber 263 is guided to the measuring unit 262 by the optical fiber 263.

  The measurement unit 262 of the first embodiment includes a so-called monochromatic radiation thermometer. The measurement unit 262 has a configuration similar to the detection unit 235 of the alignment unit 130, and includes a rotating chopper 269, a filter 270, a detection element 271, and a temperature calculation unit 273. The rotary chopper 269 has the same configuration as the rotary chopper 239 of FIG. That is, the rotary chopper 269 can shield light between the quartz rod 264 and the detection element 271 by the fan blade. Each time the rotating chopper 269 is rotated 90 ° by the motor 272, the measurement state in which the light of the thermal radiation guided by the optical fiber 263 enters the detection element 271 and the non-measurement state in which the light is blocked are switched. Change.

  The filter 270 is an optical filter that selectively transmits light having a wavelength of 2 μm or more. The detection element 271 of the first embodiment is composed of, for example, a lead sulfide element, and measures the intensity of received light using the photoelectric effect. As described above, lead sulfide has a large photoelectric effect in the infrared region of 2 μm or more, which is outside the wavelength range of the flash light of the xenon flash lamp, and the detection element 271 is suitable for detecting light in the infrared region of 2 μm or more. Lead sulfide can be expected to have a response speed of 1 millisecond or less.

  The temperature calculation unit 273 is electrically connected to the detection unit 235 and the detection element 271 of the alignment unit 130, and the output signal of the detection element 271 that has received the light of the thermal radiation guided by the optical fiber 263 and the detection unit 235. This is an arithmetic circuit that calculates the temperature of the surface of the semiconductor wafer W by an arithmetic method described later based on the reflectance of the semiconductor wafer W transmitted from. In the first embodiment, the detection element 271 and the temperature calculation unit 273 constitute a so-called monochromatic radiation thermometer. Note that the temperature calculation unit 273 may be configured by a computer having a CPU or the like, and cause the CPU to execute a program for temperature calculation.

  The temperature calculation unit 273 is also electrically connected to the temperature display unit 275, and the surface temperature of the semiconductor wafer W calculated by the temperature calculation unit 273 is displayed on the temperature display unit 275. The temperature display unit 275 may be configured by a liquid crystal display, for example, and is disposed in an operation unit or the like of the substrate processing apparatus 100.

<1-4. Processing procedure of substrate processing apparatus>
Next, a processing procedure of the semiconductor wafer W by the substrate processing apparatus 100 according to the present invention will be described. FIG. 8 is a flowchart showing a processing procedure of the substrate processing apparatus 100. A semiconductor wafer W to be processed in the substrate processing apparatus 100 is a semiconductor wafer after ion implantation.

  In the substrate processing apparatus 100, first, a plurality of semiconductor wafers W after ion implantation are placed on the indexer unit 110 in a state where a plurality of semiconductor wafers W are accommodated in the carrier 91. Then, the delivery robot 120 takes out the semiconductor wafers W to be processed one by one from the carrier 91 and carries them into the alignment unit 130 (step S1). The alignment unit 130 measures the reflectance of the surface of the semiconductor wafer W in addition to positioning to direct the direction of the semiconductor wafer W in a certain direction (step S2).

  The positioning of the semiconductor wafer W is as described above, and the reflectance measurement mechanism 230 measures the reflectance at a predetermined position on the surface of the semiconductor wafer W in a state where the semiconductor wafer W faces a certain direction. In the reflectance measurement, the light emitted from the light projecting unit 231 and reflected by the surface of the semiconductor wafer W is received by the light receiving unit 232, and the intensity of a specific wavelength of the light is measured by the detection element 241. Based on the result, the reflectance calculation unit 243 calculates the reflectance. In order to improve the accuracy of the reflectance measurement, the light emitted from the light projecting unit 231 and reflected by the surface of the semiconductor wafer W is surely received by the light receiving unit 232, and the ambient light and the light projecting unit 231 are also received. Therefore, it is necessary to prevent the direct light and the reflected light reflected from other than the surface of the semiconductor wafer W from entering the light receiving unit 232. For this purpose, a reflecting mirror 233 is provided, the light source 236, the quartz rod 237, and the condenser lens 238 are covered with a cylindrical cover, and the lamp axis of the light source 236 is formed with respect to the normal line of the surface of the semiconductor wafer W. The light projecting unit 231 and the light receiving unit 232 are installed so that the angle and the angle formed by the central axis of the quartz rod 237 are the same.

  Moreover, the said specific wavelength used for a reflectance measurement is an infrared region wavelength of 2 micrometers or more. This specific wavelength is the same as the wavelength used by the measurement unit 262 for measuring the temperature of the semiconductor wafer W during flash heating in the heat treatment unit 160. The reason why the specific wavelength is 2 μm or more is that radiation light having a wavelength outside the wavelength range of flash light from the flash lamp 69 is used for temperature measurement. That is, the temperature of the semiconductor wafer W is measured with radiation light having a wavelength of 2 μm or more outside the flash light wavelength range so that the flash light does not affect the temperature measurement, and the reflectance of the semiconductor wafer W at the wavelength of the radiation light is measured. To do.

  The reflected light received by the light receiving unit 232 is guided to the detection unit 235 by the optical fiber 234. In the detection unit 235, the rotary chopper 239 rotates at about 20 Hz, and the state where the light guided by the optical fiber 234 is blocked by the rotary chopper 239 and the state where the light enters the detection element 241 are repeated. The light that has passed through the rotating chopper 239 enters the filter 240, and light having a wavelength of 2 μm or more is selectively transmitted and enters the detection element 241.

  The detection element 241 converts the intensity of the specific wavelength in the received light into an electric signal and transmits it to the reflectance calculation unit 243. The reflectance calculation unit 243 indicates the intensity of the reflected light received by the light receiving unit 232 as the difference between the output of the detection element 241 when it is shielded by the rotary chopper 239 and the output of the detection element 241 when it is not shielded from light. The output of the detection element 241 is used. A method in which the difference between when the rotating chopper 239 is shielded from light and when it is not shielded while measuring the rotation chopper 239 while rotating (chopping) is generally referred to as an AC mode.

  The reflectance calculation unit 243 that has received the output signal from the detection element 241 calculates the reflectance R of the surface of the semiconductor wafer W to be processed based on the following formula 1.

In Equation 1, V ₀ is an output of the detection element 241 at the time of calibration of reflectance measurement, and V _wafer is an output of the detection element 241 that receives the reflected light of the semiconductor wafer W to be processed. Prior to the processing of the semiconductor wafer W to be processed, the reflectance measurement calibration is performed in advance by setting a wafer or an aluminum reflecting mirror on which an aluminum film is deposited on the alignment unit 130. The wafer on which the aluminum film is deposited almost totally reflects infrared light, and the reflectance can be regarded as “1”. The output of the detection element 241 when receiving the reflected light of the aluminum film deposited wafer having a reflectance of “1” is V ₀ . Note that both V ₀ and V _wafer are measured values in the AC mode described above.

  From Equation 1, the reflectance R of the semiconductor wafer W is calculated from the ratio between the output of the detection element 241 when the reflectance is “1” and the output of the detection element 241 that has actually received the reflected light of the semiconductor wafer W to be processed. can do.

  By the way, the following equation 2 holds among the emissivity ε, the transmittance T, and the reflectance R of the wafer.

  It is known that emissivity ε and transmissivity T are temperature-dependent in a wavelength region of 1.2 μm or more in a silicon semiconductor wafer W and are translucent at room temperature. The reflectance R of the semiconductor wafer W calculated by the reflectance calculation unit 243 based on Equation 1 is the same value when the temperature is raised by flash heating.

  When the reflectance measurement of the semiconductor wafer W to be processed is completed, the transfer arm 151a (or 151b) of the transfer robot 150 takes out the semiconductor wafer W from the alignment unit 130 into the transfer chamber 170, and the transfer robot 150 performs the heat processing unit. Turn to face 160.

  When the transfer robot 150 faces the heat processing unit 160, the transfer arm 151a (151b) carries the semiconductor wafer W taken out from the alignment unit 130 into the heat processing unit 160 (step S3). At this time, the transfer robot 150 slides the transfer arms 151 a and 151 b perpendicular to the longitudinal direction of the flash lamp 69.

  In the heat processing unit 160, the semiconductor wafer W is moved by the transfer robot 150 through the opening 66 in a state where the wafer support member 73 and the heating plate 74 are arranged at the loading / unloading positions of the semiconductor wafer W shown in FIG. It is carried in and placed on the support pin 70. This semiconductor wafer W has already been positioned so as to face a certain direction by the alignment unit 130, and is placed on the support pins 70 so that it always faces the certain direction even when it is loaded into the heat treatment unit 160. Further, this semiconductor wafer W has a surface surface reflectance R calculated by the alignment unit 130.

  When the loading of the semiconductor wafer W is completed, the opening 66 is closed by the gate valve 68. Thereafter, the wafer support member 73 and the heating plate 74 are raised to the heat treatment position of the semiconductor wafer W shown in FIG. 6 by driving the motor 40, and hold the semiconductor wafer W in a horizontal posture. Further, the on-off valve 80 and the on-off valve 81 are opened to form a nitrogen gas flow in the chamber 65.

  Wafer support member 73 and heating plate 74 are heated to a predetermined temperature in advance by the action of a heater built in heating plate 74. For this reason, in a state where the wafer support member 73 and the heating plate 74 are raised to the heat treatment position of the semiconductor wafer W, the semiconductor wafer W is preheated by coming into contact with the wafer support member 73 in a heated state, and the semiconductor wafer W The temperature gradually rises (step S4).

  In this state, the semiconductor wafer W is continuously heated via the wafer support member 73. When the temperature of the semiconductor wafer W rises, the internal temperature of the heating plate 74 is monitored by a temperature sensor inside the heating plate 74 (not shown) so that the surface temperature of the semiconductor wafer W becomes the preheating temperature T1, and reaches the set temperature. Always monitor whether or not This temperature sensor is a sensor different from the temperature measuring mechanism 260, and for example, a thermocouple or the like can be used.

  The preheating temperature T1 is a temperature of about 200 ° C. to 600 ° C., for example. Even if the semiconductor wafer W is heated to such a preheating temperature T1, ions implanted into the semiconductor wafer W will not diffuse.

  Eventually, when the surface temperature of the semiconductor wafer W reaches the preheating temperature T1, the flash lamp 69 is turned on to perform flash heating (step S5). The lighting time of the flash lamp 69 in this flash heating process is a time of about 0.1 to 10 milliseconds. Thus, in the flash lamp 69, the electrostatic energy stored in advance is converted into such an extremely short light pulse, so that an extremely strong flash light is irradiated.

  By such flash heating, the surface temperature of the semiconductor wafer W instantaneously reaches the temperature T2. This temperature T2 is a temperature necessary for the ion activation treatment of the semiconductor wafer W at about 1000 ° C. to 1100 ° C. When the surface of the semiconductor wafer W is heated to such a processing temperature T2, ions implanted into the semiconductor wafer W are activated.

  At this time, since the surface temperature of the semiconductor wafer W is raised to the processing temperature T2 in an extremely short time of about 0.1 to 10 milliseconds, ion activation in the semiconductor wafer W is completed in a short time. . Therefore, it is possible to prevent the phenomenon that ions implanted into the semiconductor wafer W diffuse. Since the time required for ion activation is extremely short compared with the time required for ion diffusion, the ion activation is performed even for a short time in which no diffusion of about 0.1 millisecond to 10 millisecond occurs. Complete.

  Further, before the flash lamp 69 is turned on to heat the semiconductor wafer W, the surface temperature of the semiconductor wafer W is heated to the preheating temperature T1 of about 200 ° C. to 600 ° C. using the heating plate 74. The flash lamp 69 makes it possible to quickly raise the temperature of the semiconductor wafer W to the processing temperature T2 of about 1000 ° C. to 1100 ° C.

  Here, in this embodiment, the surface temperature of the semiconductor wafer W is measured during flash heating. Thermal radiation corresponding to the temperature is generated from the surface of the semiconductor wafer W heated by the flash light emitted from the flash lamp 69. The temperature measuring mechanism 260 of the heat processing unit 160 measures the radiation intensity of the thermal radiation (step S6), and based on the measurement result and the reflectance R of the surface of the semiconductor wafer W measured by the alignment unit 130. The temperature of the semiconductor wafer W is calculated (step S7).

  Of the radiated light incident on the quartz rod 264 from the heated semiconductor wafer W, the light incident perpendicularly to the central axis of the quartz rod 264 is totally reflected by the cut surface at the tip of the quartz rod 264 and passes through the quartz rod 264. Propagate along its central axis.

  FIG. 9 is a diagram illustrating a state in which the radiated light from the semiconductor wafer W is totally reflected and propagates in the quartz rod 264. The cut surface 264 a of the quartz rod 264 is cut so that the normal line forms an angle of 45 ° with the central axis of the quartz rod 264. Accordingly, the light incident on the quartz rod 264 from the heated semiconductor wafer W and incident perpendicularly to the central axis of the quartz rod 264 enters the cut surface 264a at the tip of the quartz rod 264 at an incident angle of 45 °. To do.

  On the other hand, the critical angle of quartz is 43.2 °. The critical angle is the lowest incident angle at which a light beam traveling in a medium having a high refractive index (quartz) is totally reflected at the interface with a medium having a low refractive index (outside air). Therefore, as shown in FIG. 9, the light incident perpendicularly to the central axis of the quartz rod 264 is totally reflected by the cut surface 264a and propagates in the quartz rod 264 parallel to the central axis. In the first embodiment, since the quartz rod 264 has a diameter of 3 mm, thermal radiation from an elliptical region having a major axis of 4.2 mm and a minor axis of 3 mm on the surface of the semiconductor wafer W is collected by the quartz rod 264. The radiated light that does not reach the cut surface 264a even though it enters the quartz rod 264 passes through the quartz rod 264 as it is.

  In addition, the elliptical area for collecting thermal radiation is set at the same position as the area where the reflectance R is measured by the reflectance measuring mechanism 230. As described above, the reflectance measurement is performed by the alignment unit 130 after the semiconductor wafer W faces a certain direction. And the semiconductor wafer W is made to face a fixed direction also in carrying in to the heat processing part 160. FIG. Therefore, if the quartz rod 264 is installed so that the cut surface 264a is located immediately above the position where the reflectance measurement of the surface of the semiconductor wafer W is performed, the reflectance and radiation intensity at the same position of the semiconductor wafer W to be processed can be obtained. Can be measured.

  The emitted light collected by the quartz rod 264 is collected by the condenser lens 266 and incident on the optical fiber 263, and then guided to the measuring unit 262 by the optical fiber 263. When the rotation chopper 269 of the measurement unit 262 is not rotating and the surface temperature of the semiconductor wafer W is not measured, the rotation chopper 269 is in a non-measurement state in which the space between the optical fiber 263 and the detection element 271 is shielded from light. Has stopped. Then, immediately before the flash light irradiation from the flash lamp 69 is performed (about 1 second before), the rotating chopper 269 rotates 90 ° and the measurement state in which the emitted light guided by the optical fiber 263 enters the detection element 271 is switched. Change.

  Radiated light that has passed through the rotating chopper 269 enters the filter 270, and light having a wavelength of 2 μm or more is selectively transmitted and enters the detection element 271. The detection element 271 converts the intensity of the received radiation light into an electric signal and transmits it to the temperature calculation unit 273. Here, in 1st Embodiment, the intensity | strength of the light of the specific wavelength used for the reflectance measurement among the radiated light which the detection element 271 received is measured. The specific wavelength is 2 μm or more outside the wavelength range of the flash light. Then, the temperature calculation unit 273 determines the maximum value of the difference between the output of the detection element 271 when it is shielded from light by the rotating chopper 269 and the output of the detection element 271 when it is not shielded from light, as the semiconductor wafer W has the instantaneous maximum temperature. The radiation intensity of thermal radiation when reaching

  In this way, the rotation chopper 269 is not rotated, and the difference between the outputs of the detection element 271 when the rotary chopper 269 is shielded from light and not shielded as a measurement state immediately before flash heating is used as a measurement value. The method is generally called a DC mode. In the DC mode, the zero point drift is likely to occur, but in this embodiment, the measurement state is set immediately before the flash light irradiation from the flash lamp 69 is performed, so that the zero point drift is not affected. Further, in the AC mode employed for reflectance measurement, there is a possibility that the radiation light is blocked by the rotating chopper 269 at the moment when the semiconductor wafer W reaches the maximum temperature, but in the DC mode, such instantaneously obtained radiation is obtained. The light intensity can also be reliably measured by the detection element 271 receiving light. The DC mode is effective when the temperature rise time of the semiconductor wafer W is extremely short, such as flash heating. Furthermore, since the lead sulfide detecting element 271 has a very fast response speed, the radiation light at the moment when the semiconductor wafer W reaches the maximum temperature even with a very short heating time of about 0.1 to 10 milliseconds. Can be captured.

  The temperature calculation unit 273 that has received the output signal from the detection element 271 is based on the reflectance R already measured by the reflectance measurement mechanism 230 in the alignment unit 130 and the radiation intensity measured by the detection element 271 as follows. Thus, the instantaneous maximum temperature of the semiconductor wafer W to be processed is calculated.

First, the detection element 271 measures the instantaneous maximum output V _max of the detection element 271 and the radiation of the black body furnace at the temperature T when the radiation light from the semiconductor wafer W that has reached the instantaneous maximum temperature T (K) is received. Then, the following relationship is established with the output Lb (T).

  In Equation 3, ε is the emissivity of the semiconductor wafer W. As described above, the relationship of Equation 2 is established among the emissivity ε, the transmittance T, and the reflectance R of the semiconductor wafer W. The reflectance R has been measured in the alignment unit 130. The instantaneous maximum temperature of the semiconductor wafer W during flash heating is about 1000 ° C. to 1100 ° C., but the transmittance T in this temperature range can be regarded as almost “0”. Therefore, the following equation 4 is established.

  On the other hand, the output Lb (T) measured in the blackbody furnace at the temperature T can be expressed by the characteristic equation of the monochromatic radiation thermometer shown in Equation 5.

In Equation 5, A, B, and C are intrinsic constants of the monochromatic radiation thermometer. C2 is the second constant of radiation and is 1.4388 × 10 ⁻² m · K. From the formula 5, the following formula 6 is derived.

Accordingly, the temperature calculation unit 273 calculates Lb (T) from Equation 4 based on the measured reflectance R and the instantaneous maximum output V _max of the detection element 271, and further calculates the instantaneous maximum temperature of the semiconductor wafer W from Equation 6 below. T can be calculated. The intrinsic constants A, B, and C in Equations 5 and 6 are obtained in advance by calibrating the entire temperature measuring mechanism 260 including the quartz rod 264 with a black body furnace.

  FIG. 10 is a diagram showing how the temperature measuring mechanism 260 is calibrated. The connector 265 of the temperature measuring mechanism 260 is fixed to the water cooling plate 302 and the tip of the quartz rod 264 is inserted into the constant temperature region of the cavity 301 of the black body furnace. In the state shown in FIG. 10, the temperature of the cavity 301 of the blackbody furnace is changed to at least three points and the detection element 271 measures the radiation intensity, thereby calibrating the temperature measuring mechanism 260 and calculating Intrinsic constants A, B, and C can be obtained.

  After the flash heating process involving temperature measurement of the surface of the semiconductor wafer W is completed, the wafer support member 73 and the heating plate 74 are lowered to the loading / unloading position of the semiconductor wafer W shown in FIG. The opening 66 closed by the valve 68 is opened. Then, the semiconductor wafer W placed on the support pins 70 is unloaded by the transfer robot 150 (step S8).

  Next, the transfer robot 150 turns to face the cooling unit 140, and the semiconductor wafer W that has been processed by the transfer arm 151 a (or 151 b) is placed in the cooling unit 140. The semiconductor wafer W cooled by the cooling unit 140 is returned to the carrier 91 by the delivery robot 120, and a series of substrate processing is completed.

  As described above, in the first embodiment, the reflectance of the surface of the semiconductor wafer W to be processed is measured by the reflectance measuring mechanism 230 before the flash irradiation from the flash lamp 69 is performed. The detection element 271 measures the radiation intensity of thermal radiation from the surface of the semiconductor wafer W to be processed that has been irradiated with flash light and heated, and the instantaneous maximum temperature of the surface of the semiconductor wafer W is calculated from the reflectance and radiation intensity. Part 273 is calculating. In general, in order to measure the temperature of the semiconductor wafer W with a non-contact radiation thermometer, it is necessary to measure the emissivity and the radiation intensity. For accurate temperature measurement, it is most preferable to measure the emissivity and radiant intensity of the semiconductor wafer W in a heated state during heating.

  For this reason, in the lamp annealing apparatus using the conventional halogen lamp as described in Patent Document 1, two types of effective reflectivity are generated by the rotating sector during the period when the wafer is heated, and each effective reflection is generated. The emissivity and temperature of the wafer were calculated from a binary equation established by measuring the radiation intensity corresponding to the rate. However, a flash heating type apparatus with an extremely short heating time does not have time to create two types of effective reflectivity during wafer temperature rise. For this reason, in the first embodiment, the reflectance of the surface of the semiconductor wafer W to be processed is measured in advance before flash heating, and only the highest radiation intensity of thermal radiation from the semiconductor wafer W is measured during lead heating. The instantaneous maximum temperature of the surface of the semiconductor wafer W is calculated by instantaneously measuring with the detecting element 271.

  The reflectance R measured in advance by the alignment unit 130 is the reflectance of the semiconductor wafer W at room temperature, but the temperature dependence of the reflectance R is small. Also, since lead sulfide can be expected to have a response speed of 1 millisecond or less, the radiation intensity of thermal radiation from the semiconductor wafer W at the moment when the maximum temperature is reached during flash heating should be accurately measured by the lead sulfide detection element 271. Can do. For this reason, according to the apparatus of this embodiment, it is possible to accurately measure the temperature of the surface of the semiconductor wafer W heated by irradiation with flash light from the flash lamp 69.

  The reflectance measuring mechanism 230 measures the reflectance of light having a specific wavelength of 2 μm or more, and the detection element 271 measures the radiation intensity of the light having the specific wavelength emitted from the surface of the semiconductor wafer W during heating. The temperature calculation unit 273 calculates the temperature of the surface of the semiconductor wafer W from the reflectance and radiation intensity of the light having the specific wavelength. That is, the temperature measuring mechanism 260 includes a so-called monochromatic radiation thermometer that measures temperature at one wavelength. In the case of a monochromatic radiation thermometer, the detection element 271 only needs to measure the radiation intensity of the light of the specific wavelength, so that the response time is short, and it is suitable for temperature measurement of the semiconductor wafer W by flash heating with a short temperature rise time. Yes.

  Further, since 2 μm or more which is outside the wavelength range of the flash light from the flash lamp 69 is used as the measurement wavelength, even if the flash light is incident on the quartz rod 264, the temperature measurement of the semiconductor wafer W is not affected. Such flash light is removed by the filter 270.

  Further, in the first embodiment, the quartz rod 264 is disposed between the semiconductor wafer W to be processed and the flash lamp 69 accommodated in the chamber 65 without installing the measurement unit 262 directly in the chamber 65. The quartz rod 264 guides the heat radiation light from the surface of the semiconductor wafer W to the measuring unit 262. In the flash heating, only the surface of the semiconductor wafer W is instantaneously heated and the back surface is not heated so much. Therefore, it is necessary to measure the temperature from the surface side, but the quartz rod 264 is disposed on the surface side of the semiconductor wafer W. As a result, the surface temperature can be accurately measured by collecting heat radiation from the surface. Further, if the quartz rod 264 is disposed on the surface side of the semiconductor wafer W, intense flash light does not directly reach the measurement unit 262, and the measurement unit 262 further inhibits the flash irradiation of the semiconductor wafer W ( There is no concern about the measurement unit 262 being a shadow.

  In the first embodiment, since the reflectance and radiation intensity at the same position on the surface of the semiconductor wafer W are measured and measured for temperature, the reflectance at the position where the radiation intensity is measured is used to measure the semiconductor wafer W. The surface temperature can be calculated, and more accurate temperature measurement is possible.

  In the first embodiment, the reflectance measurement mechanism 230 is disposed in the alignment unit 130, and the reflectance of the semiconductor wafer W to be processed is measured by the alignment unit 130. The alignment unit 130 is a part of the transport path (outward path) of the semiconductor wafer W from the indexer unit 110 to the heat treatment unit 160. Therefore, a special transfer process for measuring the reflectance is not necessary, and the surface reflectivity of the semiconductor wafer W can be measured during the normal transfer procedure from the indexer unit 110 to the heat treatment unit 160. The temperature of the semiconductor wafer W can be measured without greatly reducing the throughput.

<2. Second Embodiment>
Next, a second embodiment of the present invention will be described. The configuration of the substrate processing apparatus of the second embodiment is substantially the same as that of the first embodiment. Further, the processing procedure of measuring the reflectance of the surface of the semiconductor wafer W in advance by the alignment unit 130 and then measuring the radiation intensity during flash heating to calculate the instantaneous maximum temperature of the surface is almost the same as in the first embodiment. is there.

  In the first embodiment, the temperature is measured by a monochromatic radiation thermometer, but in the second embodiment, the surface temperature of the semiconductor wafer W is measured by a two-color radiation thermometer. First, in the second embodiment, with respect to the semiconductor wafer W that is carried into the alignment unit 130 and positioned, the reflectance measurement mechanism 230 uses the first wavelength λ1 and the second wavelength λ2 of light having a wavelength of 2 μm or more. Measure reflectivity. Except for measuring the reflectance of two colors, the specific reflectance measurement method is the same as that of the first embodiment. That is, the reflectance R1 of the first wavelength λ1 and the reflectance R2 of the second wavelength λ2 are calculated from Equation 1, respectively. The reason why both measurement wavelengths of the first wavelength λ1 and the second wavelength λ2 are set to 2 μm or more is to eliminate the influence of the flash light on the temperature measurement as in the first embodiment.

  The measurement unit 262 of the second embodiment includes a so-called two-color radiation thermometer. At the time of flash heating, the radiation intensity of each of the light having the first wavelength λ1 and the second wavelength λ2 used for the reflectance measurement among the radiated light received by the detection element 271 is measured. The specific measurement method at this time is also the same as in the first embodiment. That is, during flash heating from the flash lamp 69, thermal radiation light from the surface of the semiconductor wafer W is sampled by the quartz rod 264, and each intensity of the first wavelength λ1 and the second wavelength λ2 of the collected radiation light. Is measured by the detecting element 271 in the DC mode. Subsequently, the temperature calculation unit 273 calculates an emissivity ratio obtained from the reflectance R1 of the light having the first wavelength λ1 and the reflectance R2 of the light having the second wavelength λ2, and the radiation intensity and the second wavelength of the light having the first wavelength λ1. The instantaneous maximum temperature of the surface of the semiconductor wafer W to be processed is calculated from the ratio of the radiant intensity with the radiant intensity of light of λ2 as follows.

  If the surface of the semiconductor wafer W reaches the instantaneous maximum temperature T (K) during the flash heating, the radiation intensity ratio M (T) from the surface of the semiconductor wafer W at both the first wavelength λ1 and the second wavelength λ2 is measured. Is expressed by the following equation (7).

  In Equation 7, L (λ1, T) is the radiation intensity when the detecting element 271 measures the radiated light having the wavelength λ1 from the black body furnace at the temperature T. Similarly, L (λ2, T) is the temperature T Radiant intensity when the radiation of wavelength λ2 from the blackbody furnace is measured by the detection element 271. On the other hand, according to Wien's equation, black body radiation intensity L (λ, T) when radiation light having a wavelength λ is measured by a detection element 271 from a black body furnace at a temperature T is expressed by Equation 8.

  From Equation 7 and Equation 8, the following Equation 9 is established.

  In Equation 9, C2 is the second constant of radiation shown in the first embodiment. Λ1 and λ2 are known values set in advance. Therefore, the radiation intensity ratio M (T) is a function of only the temperature T, and the following formula 10 is derived.

  Radiation intensity ratio between the radiation intensity of the light of the first wavelength λ1 and the radiation intensity of the light of the second wavelength λ2 measured by the detection element 271 when the radiation light from the semiconductor wafer W that has reached the instantaneous maximum temperature T is received. M (S) is expressed by the following equation 11.

  In Equation 11, ε (λ1, T) is the emissivity of light having the first wavelength λ1 on the surface of the semiconductor wafer W at the temperature T, and ε (λ2, T) is the second emissivity on the surface of the semiconductor wafer W at the temperature T. This is the emissivity of light of wavelength λ2. Therefore, ε (λ1, T) / ε (λ2, T) is an emissivity ratio εr between the first wavelength λ1 and the second wavelength λ2 on the surface of the semiconductor wafer W. The following equation 12 is derived from the equation 11.

  In Equation 12, R1 and R2 are the reflectance of the first wavelength λ1 and the reflectance of the second wavelength λ2 on the surface of the semiconductor wafer W that has already been measured in the alignment unit 130. In the temperature range reached by the semiconductor wafer W during flash heating, the transmittance is almost “0”. Therefore, the emissivity ratio εr = ε (λ1, T) from the reflectance R1 of the light having the first wavelength λ1 and the reflectance R2 of the light having the second wavelength λ2 measured by the reflectance measurement mechanism 230 in the alignment unit 130. / Ε (λ2, T) = (1-R1) / (1-R2) is obtained. M (T) is calculated from the emissivity ratio εr and the radiation intensity ratio M (S) between the radiation intensity of the light of the first wavelength λ1 and the radiation intensity of the light of the second wavelength λ2 actually measured by the detection element 271. It is done. Then, the instantaneous maximum temperature T of the semiconductor wafer W can be calculated by substituting the determined M (T) into Equation 10.

  Also in the second embodiment, the reflectance of the surface of the semiconductor wafer W to be processed is measured by the reflectance measuring mechanism 230 before the flash lamp 69 is irradiated with the flash light, and the flash lamp 69 is irradiated with the flash light. The detection element 271 measures the radiation intensity of heat radiation from the surface of the heated semiconductor wafer W to be processed, and the temperature calculation unit 273 calculates the instantaneous maximum temperature of the surface of the semiconductor wafer W from the reflectance and radiation intensity. ing. For this reason, similarly to the first embodiment, the temperature of the surface of the semiconductor wafer W heated by irradiation with flash light from the flash lamp 69 can be accurately measured.

  In particular, the temperature measuring mechanism 260 of the second embodiment includes a so-called two-color radiation thermometer that measures temperatures at two wavelengths. Such temperature measurement using a two-color radiation thermometer is effective when the emissivity of the semiconductor wafer W to be processed has a large temperature dependence. For example, in the case of a semiconductor wafer W having an amorphous silicon film formed on the surface, it is known that crystal growth occurs and the emissivity of the surface fluctuates greatly when heated to 500 ° C. or higher during preheating. In such a case, even if the emissivity of the semiconductor wafer W is calculated from the reflectivity measured at room temperature, the actual emissivity at the time of flash heating is different from the calculated emissivity.

  However, even if the emissivity is temperature-dependent as in the above example, it can be considered that the emissivity ratio has almost no temperature dependence. This is because when the emissivity at the wavelength λ1 varies with temperature, the emissivity at the wavelength λ2 is considered to vary in the same manner. Therefore, if the temperature of the surface of the semiconductor wafer W is measured from the ratio of the emissivity ratio and the actually measured radiation intensity using a two-color radiation thermometer as in the second embodiment, Even when the emissivity is temperature-dependent, accurate temperature measurement can be performed. In order to reduce the temperature dependence of the emissivity ratio as much as possible, it is preferable to reduce the wavelength width between the first wavelength λ1 and the second wavelength λ2, which are measurement wavelengths.

  However, the response speed of the two-color radiation thermometer is slower than that of the single-color radiation thermometer. For this reason, if the flash irradiation time from the flash lamp 69 is too short, there is a concern that effective measurement becomes difficult, and the second time when the lighting time of the flash lamp 69 is relatively long, such as about 5 milliseconds to 10 milliseconds. It is preferable to employ the embodiment.

<3. Modification>
While the embodiments of the present invention have been described above, the present invention is not limited to the above examples. For example, in each of the above embodiments, the light source 5 is provided with 30 flash lamps 69, but the present invention is not limited to this, and the number of flash lamps 69 may be arbitrary.

  Further, the technique according to the present invention can be applied to a heat treatment apparatus that includes another type of lamp (for example, a halogen lamp) instead of the flash lamp 69 in the light source 5 and heats the semiconductor wafer W by light irradiation from the lamp. Can be applied. Furthermore, the technique according to the present invention can be applied to a continuous arc lamp annealing apparatus and a photo-CVD apparatus. Even in these cases, the reflectance of the semiconductor wafer W is measured in advance before the heat treatment, and the temperature of the processing target wafer is calculated from the reflectance and the radiation intensity from the wafer surface during the heat treatment. Just do it.

  Moreover, in the said embodiment, although the two carriers 91 are mounted in the board | substrate accommodating part 110, only one carrier 91 may be mounted and three or more may be sufficient. Further, although the delivery robot 120 moves between the two carriers 91, two delivery robots 120 may be provided.

  The upper transfer arm 151a of the transfer robot 150 is designed as a dedicated arm for holding the unprocessed semiconductor wafer W, and the lower transfer arm 151b is designed as a dedicated arm for holding the processed semiconductor wafer W. Thus, the transport robot 150 can be reduced in size and transport reliability can be improved.

  Further, the reflectance measuring mechanism 230 is not limited to being disposed in the alignment unit 130, and may be disposed on any one of the transport paths of the semiconductor wafer W from the indexer unit 110 to the heat treatment unit 160. If the reflectance measuring mechanism 230 is disposed on the transport path of the semiconductor wafer W from the indexer section 110 to the heat treatment section 160, that is, the forward path, the surface reflectance of the semiconductor wafer W is measured during the normal transport procedure. The temperature of the semiconductor wafer W can be measured without greatly reducing the throughput. In particular, in order to perform the reflectance measurement and the radiation intensity measurement at the same position on the surface of the semiconductor wafer W, it is necessary to measure the reflectance after alignment. 170 may be installed. Further, the reflectance measurement mechanism 230 may be provided in the heat treatment unit 160 itself, and the reflectance of the surface of the semiconductor wafer W may be measured before flash heating.

  In the above embodiment, the semiconductor wafer is irradiated with light to perform the ion activation process. However, the substrate to be processed by the substrate processing apparatus according to the present invention is not limited to the semiconductor wafer. Absent. For example, the glass substrate on which various silicon films such as a silicon nitride film and a polycrystalline silicon film are formed may be processed by the substrate processing apparatus according to the present invention. As an example, an amorphous silicon film made amorphous by ion implantation of silicon into a polycrystalline silicon film formed on a glass substrate by a CVD method is formed, and a silicon oxide film serving as an antireflection film is further formed thereon. Form. In this state, the entire surface of the amorphous silicon film can be irradiated with the substrate processing apparatus according to the present invention to form a polycrystalline silicon film in which the amorphous silicon film is polycrystallized. When the temperature dependence of the emissivity of the substrate to be processed is large, it is preferable to adopt the second embodiment.

  Further, a substrate according to the present invention is formed on a TFT substrate having a structure in which a base silicon oxide film and a polysilicon film obtained by crystallizing amorphous silicon are formed on a glass substrate, and the polysilicon film is doped with impurities such as phosphorus and boron. It is also possible to activate the impurities implanted in the doping process by irradiating light with a processing apparatus.

It is a top view of the substrate processing apparatus concerning the present invention. 1 is a front view of a substrate processing apparatus according to the present invention. It is a sectional side view which shows schematic structure of the alignment part of the substrate processing apparatus of FIG. It is a top view of the rotation chopper of the alignment part of FIG. It is a sectional side view which shows the heat processing part of the substrate processing apparatus of FIG. It is a sectional side view which shows the heat processing part of the substrate processing apparatus of FIG. It is a figure which shows the structure of the temperature measurement mechanism of a heat processing part. It is a flowchart which shows the process sequence of the substrate processing apparatus of FIG. It is a figure which shows a mode that the radiated light from a semiconductor wafer propagates by totally reflecting in the quartz rod. It is a figure which shows the mode of calibration of a temperature measuring mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 5 Light source 65 Chamber 69 Flash lamp 73 Wafer support member 74 Heating plate 100 Substrate processing apparatus 110 Indexer part 130 Alignment part 140 Cooling part 150 Transfer robot 160 Heat processing part 170 Transfer chamber 230 Reflectivity measuring mechanism 231 Light projection part 232 Light reception part 233 Reflector 260 Temperature measuring mechanism 262 Measuring unit 264 Quartz rod 269 Rotating chopper 270 Filter 271 Detection element 272 Motor 273 Temperature calculating unit W Semiconductor wafer

Claims (8)

A substrate processing apparatus for heating a substrate by irradiating a flash with the substrate,
A heat treatment chamber for accommodating a substrate and performing heat treatment;
A flash lamp for irradiating the surface of the substrate accommodated in the heat treatment chamber with flash light;
Reflectivity measuring means for measuring the reflectivity of the surface of the substrate to be processed before the flash irradiation from the flash lamp is performed;
A radiation intensity measuring means for measuring a radiation intensity of thermal radiation from the surface of the substrate to be processed which is heated by being irradiated with flash light from the flash lamp;
Temperature calculating means for calculating the temperature of the substrate to be processed from the reflectance measured by the reflectance measuring means and the radiation intensity measured by the radiation intensity measuring means;
A substrate processing apparatus comprising: The substrate processing apparatus according to claim 1,
The reflectance measuring means measures the reflectance of light having a predetermined wavelength of 2 μm or longer,
The substrate processing apparatus, wherein the radiation intensity measuring means measures a radiation intensity of the light having the predetermined wavelength. The substrate processing apparatus according to claim 1,
The reflectance measuring means measures the reflectance of each of the light having the first wavelength and the second wavelength having a wavelength of 2 μm or more,
The radiant intensity measuring means measures the radiant intensity of each of the light of the first wavelength and the second wavelength,
The temperature calculating means includes an emissivity ratio obtained from a reflectance of the light of the first wavelength and a reflectance of the light of the second wavelength, a radiation intensity of the light of the first wavelength, and a radiation intensity of the light of the second wavelength. A substrate processing apparatus that calculates the temperature of the substrate to be processed from the radiation intensity ratio. In the substrate processing apparatus in any one of Claims 1-3,
A quartz rod is further provided between the processing target substrate accommodated in the heat processing chamber and the flash lamp, and guides heat radiation from the surface of the processing target substrate to the radiation intensity measuring means. Substrate processing equipment. The substrate processing apparatus according to claim 4, wherein
A light shielding member that shields light between the quartz rod and the radiation intensity measuring means;
Moving means for moving the light shielding member so as to switch between a measurement state in which thermal radiation from the substrate to be processed enters the radiation intensity measurement means and a non-measurement state in which the thermal radiation is shielded;
Further comprising
The substrate processing apparatus, wherein the moving means moves the light shielding member so as to be in the measurement state immediately before the flash light is emitted from the flash lamp. In the substrate processing apparatus in any one of Claims 1-5,
The substrate processing apparatus, wherein the reflectance measuring unit and the radiation intensity measuring unit respectively measure a reflectance and a radiation intensity at substantially the same position on the surface of the substrate to be processed. In the substrate processing apparatus in any one of Claims 1-6,
It further includes an indexer unit for carrying an untreated substrate into the apparatus,
The substrate processing apparatus, wherein the reflectivity measuring means is disposed on a substrate transfer system path from the indexer unit to the heat treatment chamber. The substrate processing apparatus according to claim 7, wherein
It further comprises an alignment unit that directs the orientation of the untreated substrate in a certain direction,
The substrate processing apparatus, wherein the reflectance measuring unit is disposed in the alignment unit.

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