JP2014092535A - Temperature measurement device and thermal treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature measurement device capable of accurately measuring temperatures of a plurality of positions of a base material, and a thermal treatment device incorporating the temperature measurement device.SOLUTION: Three light-receiving sensors 21 are provided on a pyrometer 81. A single wide-angle lens system 82 is provided for the three light-receiving sensors 21. Radiation light beams radiated from three different positions of a semiconductor wafer are individually guided to the three light-receiving sensors 21 by the single wide-angle lens system 82. Signals output from the three light-receiving sensors 21 having received the radiation light beams radiated from the three different positions are sequentially processed by a temperature calculation part to determine the temperatures of three regions of the semiconductor wafer. Thereby, it is possible to eliminate variations among devices due to the distances from measurement target regions to the pyrometer 81, an arrangement angle, a lens system and the like, and the temperatures of the three different positions of the semiconductor wafer can be accurately measured in a non-contact manner.

Description

  The present invention relates to a temperature measuring device that measures the temperature of a plurality of locations on a base material in a non-contact manner, and a thin plate-like precision electronic substrate (hereinafter simply referred to as “substrate”) such as a semiconductor wafer incorporating the temperature measuring device. ).

  Conventionally, various heat treatments have been performed on a substrate such as a semiconductor wafer in a manufacturing process of a semiconductor device or the like. As a heat treatment method for a semiconductor wafer, a rapid thermal process (RTP) is widely used. In a typical RTP apparatus, a semiconductor wafer held in a chamber is irradiated with light from a halogen lamp, and the temperature of the semiconductor wafer is raised to a predetermined processing temperature in a short time of about several seconds. By rapidly raising the temperature of the semiconductor wafer, activation thereof can be performed while suppressing diffusion of impurities implanted by, for example, ion implantation. In addition, spike annealing is also performed in which the semiconductor wafer reaches the processing temperature by the rapid temperature rise and the rapid temperature decrease starts at the same time without holding the semiconductor wafer at the processing temperature using the RTP apparatus.

  In such an RTP apparatus, as disclosed in, for example, Patent Document 1, a plurality of halogen lamps are divided into a plurality of zones, and a pyrometer (radiation thermometer) corresponding to each zone is provided, and measurement is performed by the pyrometer. The output of the halogen lamp is controlled for each zone based on the wafer temperature. Since the pyrometer can only measure the temperature of a partial region of the semiconductor wafer, the RTP device calculates the average temperature of the concentric zone by rotating the semiconductor wafer during the heat treatment, and performs the feedback control of the halogen lamp based on it. Yes.

JP 2003-86528 A

  The pyrometer receives light emitted from a semiconductor wafer, measures the intensity (light quantity), and obtains the temperature of the measurement target region in a non-contact manner from the intensity. The pyrometer, which is a non-contact type thermometer, has factors that can cause various measurement errors such as distance from the measurement target area, angle, light receiving efficiency of the lens system and sensor, and the size of the focal point. To do. In particular, the temperature of the light receiving sensor itself provided in the pyrometer causes a large measurement error as thermal noise.

  For this reason, even if pyrometers of the same specification are installed at different positions in the apparatus and the temperature of the same region of the semiconductor wafer heated to a predetermined temperature is measured, different measurement results are often obtained. Therefore, as disclosed in Patent Document 1, even if a pyrometer is provided for each zone and the temperature of different regions of the semiconductor wafer is measured, the obtained measurement results accurately indicate the temperature distribution of the semiconductor wafer. There has been a problem that it cannot be determined whether it is a measurement error due to a difference in the pyrometer.

  Therefore, it is conceivable to correct measurement errors due to machine differences by adjusting (calibrating) the electric circuit portion that processes the output signal for each pyrometer. However, even if an adjustment is made to eliminate the pyrometer error for a certain temperature, a new error will occur if the temperature of the measurement object is different. As a result, it has been extremely difficult to accurately measure a plurality of locations on a semiconductor wafer to be measured simultaneously.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a temperature measuring apparatus capable of accurately measuring temperatures at a plurality of locations on a base material and a heat treatment apparatus incorporating the temperature measuring apparatus. To do.

  In order to solve the above-mentioned problem, the invention of claim 1 is a temperature measurement device that measures the temperature of a plurality of locations of a base material in a non-contact manner, and a plurality of light receiving sensors that receive radiation emitted from the base material, A single lens system that individually guides the radiated light emitted from a plurality of locations of the base material to one of the plurality of light receiving sensors, and the plurality of light receiving devices based on the intensity of the radiated light received by each of the plurality of light receiving sensors. A temperature calculation unit that individually calculates the temperature of the location, and the radiated light emitted from one of the plurality of locations is guided to each of the plurality of light receiving sensors by the single lens system. And

  According to a second aspect of the present invention, in the temperature measuring device according to the first aspect of the present invention, a single storage unit that stores the plurality of light receiving sensors, and a cooling unit that cools the single storage unit. It is further provided with the feature.

  The invention of claim 3 is the temperature measuring device according to claim 1 or claim 2, wherein the temperature calculation unit calculates the temperature by sequentially processing signals from the plurality of light receiving sensors. The arithmetic circuit is included.

  According to a fourth aspect of the present invention, in the temperature measurement device according to any one of the first to third aspects of the present invention, the single lens system is a wide-angle lens system.

  The invention of claim 5 is a heat treatment apparatus, comprising: a chamber that accommodates the substrate; a heating unit that heats the substrate accommodated in the chamber; and temperatures at a plurality of locations of the substrate heated by the heating unit. And a temperature measuring device according to any one of claims 1 to 4 to be measured.

  Further, the invention of claim 6 is the heat treatment apparatus according to the invention of claim 5, wherein the heating unit includes a lamp for irradiating the substrate accommodated in the chamber to heat the substrate. To do.

  According to the first to fourth aspects of the present invention, since the radiated light radiated from a plurality of locations of the base material is individually guided to the plurality of light receiving sensors by the single lens system, the difference between the plurality of light receiving sensors is reduced. Without it, it is possible to accurately measure the temperature at a plurality of locations on the substrate.

  In particular, according to the invention of claim 2, in order to cool a single storage portion that stores a plurality of light receiving sensors, the temperature difference between the plurality of light receiving sensors is eliminated, the thermal noise is made uniform, The temperature can be measured more accurately.

  In particular, according to the invention of claim 3, since the temperature is calculated by sequentially processing signals from a plurality of light receiving sensors by a common arithmetic circuit, it is possible to eliminate the machine difference caused by the electric circuit. Can be measured more accurately.

  Moreover, according to the invention of Claim 5 and Claim 6, the temperature of the several location of the board | substrate heated by the heating part can be measured correctly.

It is a figure which shows the principal part structure of the heat processing apparatus which concerns on this invention. It is a top view which shows arrangement | positioning of a some halogen lamp. It is a figure which shows the structure of a pyrometer. It is an external appearance perspective view of a holder. It is a block diagram which shows the structure of a temperature calculation part. It is a figure which shows the spectral transmittance of a silicon | silicone. It is a figure which shows the area | region of three places of the semiconductor wafer used as a measuring object by three light receiving sensors. It is a figure which shows the other example of an external appearance perspective view of a holder. It is a figure which shows the area | region of seven places of the semiconductor wafer used as a measuring object by seven light receiving sensors. It is a figure which shows an example of a structure which provides two pyrometers.

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

  FIG. 1 is a diagram showing a main configuration of a heat treatment apparatus 1 according to the present invention. The heat treatment apparatus 1 is a lamp annealing apparatus that performs heat treatment (backside annealing) of the semiconductor wafer W by irradiating light to the back surface of the circular semiconductor wafer W having a diameter of 300 mm. In FIG. 1 and the subsequent drawings, the size and number of each part are exaggerated or simplified as necessary for easy understanding.

  The heat treatment apparatus 1 mainly includes a substantially cylindrical chamber 6 that accommodates a semiconductor wafer W, a holding unit 7 that holds the semiconductor wafer W in the chamber 6, and a semiconductor wafer W held by the holding unit 7. The light irradiation part 4 which irradiates light, and the temperature measurement part 8 which detects the temperature of the semiconductor wafer W irradiated with light are provided. In addition, the heat treatment apparatus 1 includes a control unit 3 that controls each of these units to perform the heat treatment of the semiconductor wafer W.

The chamber 6 has a substantially cylindrical side wall that is open at the top and bottom. The chamber 6 is made of, for example, a metal material having excellent strength and heat resistance such as stainless steel. A quartz window 64 is attached to the lower opening of the chamber 6 and is closed. The quartz window 64 disposed at the lower end of the chamber 6 is a disk-shaped member formed of quartz (SiO ₂ ), and transmits the light irradiated from the light irradiation unit 4 into the chamber 6.

  An infrared transmission window 63 is attached to the upper opening of the chamber 6 to close it. The infrared transmission window 63 disposed at the upper end of the chamber 6 is a disk-shaped member made of silicon (Si). The diameter of the infrared transmission window 63 is 300 mm, which is the same as that of the semiconductor wafer W. Such an infrared transmission window 63 can be manufactured at low cost by using, for example, a silicon single crystal ingot from which a semiconductor wafer W is cut out and a disc having a predetermined thickness (3 mm in this embodiment) cut out. be able to. As will be described in detail later, silicon is opaque to visible light (not transmitting visible light), but has a property of transmitting infrared light having a wavelength exceeding 1 μm at a predetermined temperature or lower. Accordingly, the infrared rays emitted from the semiconductor wafer W that has been heated by receiving the light irradiation from the light irradiation unit 4 are transmitted through the infrared transmission window 63 at the upper end of the chamber 6 and emitted above the chamber 6.

  A space surrounded by the quartz window 64, the infrared transmission window 63 and the side wall of the chamber 6 is defined as a heat treatment space 65. In order to maintain the airtightness of the heat treatment space 65, the quartz window 64, the infrared transmission window 63, and the chamber 6 are respectively sealed by O-rings (not shown) to prevent gas from flowing in and out through the gaps. It is out. Specifically, an O-ring is sandwiched between the upper peripheral edge of the quartz window 64 and the chamber 6, the clamp ring 66 is brought into contact with the lower peripheral edge of the quartz window 64, and the clamp ring 66 is screwed to the chamber 6. By doing so, the quartz window 64 is pressed against the O-ring. Similarly, an O-ring is sandwiched between the lower peripheral edge of the infrared transmission window 63 and the chamber 6, the clamp ring 62 is brought into contact with the upper peripheral edge of the infrared transmission window 63, and the clamp ring 62 is placed in the chamber 6. The infrared transmission window 63 is pressed against the O-ring by screwing.

  A transfer opening 67 for carrying in and out the semiconductor wafer W is provided on the side wall of the chamber 6. The transfer opening 67 can be opened and closed by a gate valve (not shown). When the transfer opening 67 is opened, the semiconductor wafer W can be carried into and out of the chamber 6 by a transfer robot (not shown). When the transfer opening 67 is closed, the heat treatment space 65 becomes a sealed space in which ventilation with the outside is blocked.

  The holding unit 7 is fixedly installed inside the chamber 6 and includes a holding plate 71 and a support pin 72. The entire holding portion 7 including the holding plate 71 and the support pins 72 is made of quartz. The holding plate 71 is fixedly installed inside the chamber 6 so as to be in a horizontal posture. On the upper surface of the holding plate 71, a plurality (at least three) of support pins 72 are erected along the circumference. The diameter of the circle formed by the plurality of support pins 72 is slightly smaller than the diameter of the semiconductor wafer W. Therefore, the semiconductor wafer W can be mounted and supported in a horizontal posture (a posture in which the normal line of the semiconductor wafer W is along the vertical direction) by the plurality of support pins 72. Instead of the plurality of support pins 72, a quartz ring smaller than the diameter of the semiconductor wafer W may be provided on the upper surface of the holding plate 71.

  A transfer mechanism 5 is provided inside the chamber 6. The transfer mechanism 5 includes a pair of transfer arms 51 and lift pins 52 provided on the upper surface of each transfer arm 51. For example, two lift pins 52 are provided in each of the two transfer arms 51. The two transfer arms 51 and the four lift pins 52 are both made of quartz. The pair of transfer arms 51 are moved up and down along the vertical direction by a lifting drive unit (not shown). When the pair of transfer arms 51 are raised, a total of four lift pins 52 pass through the through holes formed in the holding plate 71, and their upper ends protrude from the upper surface of the holding plate 71 to be higher than the support pins 72. To reach. On the other hand, when the transfer arm 51 is lowered, the upper end of the lift pin 52 is positioned below the holding plate 71 as shown in FIG. In the state where the transfer arm 51 is lowered, the pair of transfer arms 51 may be opened and closed along the horizontal direction by an opening / closing mechanism.

  The light irradiation unit 4 is provided below the chamber 6. The light irradiation unit 4 includes a plurality of halogen lamps HL and reflectors 43. In the present embodiment, the light irradiation unit 4 is provided with 40 halogen lamps HL. The plurality of halogen lamps HL irradiate the heat treatment space 65 from below the chamber 6 through the quartz window 64. FIG. 2 is a plan view showing the arrangement of the plurality of halogen lamps HL. In the present embodiment, 20 halogen lamps HL are arranged in two upper and lower stages. Each halogen lamp HL is a rod-shaped lamp having a long cylindrical shape. The 20 halogen lamps HL in both the upper and lower stages are arranged so that their longitudinal directions are parallel to each other along the main surface of the semiconductor wafer W held by the holding unit 7 (that is, along the horizontal direction). Yes. Therefore, the plane formed by the arrangement of the halogen lamps HL in both the upper stage and the lower stage is a horizontal plane.

  In addition, as shown in FIG. 2, the arrangement density of the halogen lamps HL in the region facing the peripheral portion is higher than the region facing the central portion of the semiconductor wafer W held by the holding portion 7 in both the upper and lower steps. Yes. That is, in both the upper and lower stages, the arrangement pitch of the halogen lamps HL is shorter on the end side than on the center part of the lamp array. For this reason, it is possible to irradiate a larger amount of light to the peripheral portion of the semiconductor wafer W where the temperature is likely to decrease during heating by light irradiation from the light irradiation unit 4.

  Further, the lamp group composed of the upper halogen lamp HL and the lamp group composed of the lower halogen lamp HL are arranged so as to intersect in a lattice pattern. That is, a total of 40 halogen lamps HL are arranged so that the longitudinal direction of the upper halogen lamps HL and the longitudinal direction of the lower halogen lamps HL are orthogonal to each other.

  The halogen lamp HL is a filament-type light source that emits light by making the filament incandescent by energizing the filament disposed inside the glass tube. Inside the glass tube, a gas obtained by introducing a trace amount of a halogen element (iodine, bromine, etc.) into an inert gas such as nitrogen or argon is enclosed. By introducing a halogen element, it is possible to set the filament temperature to a high temperature while suppressing breakage of the filament. Therefore, the halogen lamp HL has a characteristic that it has a longer life than a normal incandescent bulb and can continuously radiate strong light. Further, since the halogen lamp HL is a rod-shaped lamp, it has a long life, and by arranging the halogen lamp HL along the horizontal direction, the radiation efficiency to the upper semiconductor wafer W becomes excellent.

  Further, the reflector 43 is provided below the plurality of halogen lamps HL so as to cover all of them. The basic function of the reflector 43 is to reflect the light emitted from the plurality of halogen lamps HL to the heat treatment space 65 in the chamber 6. The reflector 43 is made of, for example, an aluminum alloy plate, and the surface (the surface facing the flash lamp FL) is roughened by blasting.

  Returning to FIG. 1, a temperature measuring unit 8 is provided above the chamber 6. The temperature measuring unit 8 includes a pyrometer 81. FIG. 3 is a diagram showing the structure of the pyrometer 81. The pyrometer 81 includes a wide-angle lens system 82 and three light receiving sensors 21. The wide-angle lens system 82 is formed by joining five convex and concave lenses in order from the top. A diaphragm 83 is provided in the second lens (second convex lens from the top). The wide-angle lens system 82 is configured such that the imaging position for an object at infinity is on the plane in which the three light receiving sensors 21 are arranged. In the present embodiment, a single wide-angle lens system 82 is provided for the three light-receiving sensors 21, and the emitted light from the semiconductor wafer W is guided to the three light-receiving sensors by the common wide-angle lens system 82. . The wide-angle lens system 82 is not limited to that illustrated in FIG. 3, and various known lens systems can be employed.

  The light receiving sensor 21 receives the light guided by the wide-angle lens system 82 and outputs an electric signal having a level corresponding to the intensity thereof. In the present embodiment, three light receiving sensors 21 are provided in one pyrometer 81. The three light receiving sensors 21 are accommodated in a single holder 25. FIG. 4 is an external perspective view of the holder 25. The holder 25 is made of a metal such as aluminum (Al). The holder 25 is formed with three storage holes, and one light receiving sensor 21 is stored in each hole.

  As shown in FIG. 3, a Peltier element 27 is attached to the holder 25. The Peltier element 27 cools the holder 25 by a Peltier effect that causes heat transfer from one surface to the other surface when energized. In the present embodiment, since the three light receiving sensors 21 are accommodated in the common holder 25, the three light receiving sensors 21 are uniformly cooled to the same temperature by the Peltier element 27.

  The pyrometer 81 is installed above the chamber 6 so that the leading concave lens (the lens opposite to the side where the light receiving sensor 21 is provided) of the wide-angle lens system 82 faces the infrared transmission window 63. The light receiving sensor 21 of the pyrometer 81 detects infrared rays having a wavelength of 1 μm or more. The infrared transmission window 63 formed of silicon transmits infrared rays having a wavelength of 1 μm or more. That is, infrared rays having a wavelength of 1 μm or more emitted from the heat treatment space 65 in the chamber 6 are transmitted through the infrared transmission window 63 and detected by the pyrometer 81, and the pyrometer 81 is located below the infrared transmission window 63. The emitted light emitted from the semiconductor wafer W can be detected.

  FIG. 5 is a block diagram illustrating a configuration of the temperature calculation unit 91. The three light receiving sensors 21 provided in the pyrometer 81 are electrically connected to the multiplexer 85. The multiplexer 85 is a circuit that selects and outputs one of a plurality of input signals, as schematically shown in FIG. In the present embodiment, the multiplexer 85 selects one of the signals transmitted from the three light receiving sensors 21 and outputs the selected signal to the temperature calculation unit 91.

  The temperature calculation unit 91 includes an A / D converter 92 and a calculation unit 93. The A / D converter 92 converts the electrical signal (analog) transmitted from the light receiving sensor 21 via the multiplexer 85 into a digital signal. The calculation unit 93 calculates the temperature by performing calculation processing based on the digital signal output from the A / D converter 25. The calculation unit 93 may be realized by, for example, a one-chip microcomputer in which a CPU, a memory, a timer, and the like are mounted on one IC chip. With a one-chip microcomputer, processing cannot be performed, but specific processing can be performed at high speed.

  The temperature calculation unit 91 and the control unit 3 are connected via a communication line. The control unit 3 controls the various operation mechanisms provided in the heat treatment apparatus 1. The configuration of the control unit 3 as hardware is the same as that of a general computer. That is, the control unit 3 stores a CPU that performs various arithmetic processes, a ROM that is a read-only memory that stores basic programs, a RAM that is a readable and writable memory that stores various information, control software, data, and the like. It is configured with a magnetic disk. The processing in the heat treatment apparatus 1 proceeds as the CPU of the control unit 3 executes a predetermined processing program. Further, the temperature calculation result of the semiconductor wafer W by the temperature calculation unit 91 is transmitted to the control unit 3, and the output of the light irradiation unit 4 is also controlled by the control unit 3 based on the result. The communication line connecting the temperature calculation unit 91 and the control unit 3 may be serial communication or parallel communication.

  Returning to FIG. 1, the heat treatment apparatus 1 is provided with a cooling unit 69 for cooling the infrared transmission window 63. In the present embodiment, a blower is used as the cooling unit 69. The cooling unit 69 is provided outside the chamber 6 and air-cools the infrared transmission window 63 by blowing air toward the upper surface of the infrared transmission window 63. The cooling unit 69 may include a temperature adjustment mechanism for adjusting the temperature of the blown air.

In addition to the above configuration, the heat treatment apparatus 1 has a mechanism for adjusting the atmosphere of the heat treatment space 65, for example, nitrogen (N ₂ ), oxygen (O ₂ ), hydrogen (H ₂ ), hydrogen chloride (HCl), ammonia (NH ₃ ). ) And the like, and an exhaust mechanism for exhausting the atmosphere in the heat treatment space 65 to the outside of the apparatus. Further, a water cooling tube for preventing an excessive temperature rise of the chamber 6 due to light irradiation from the light irradiation unit 4 may be provided on the side wall of the chamber 6.

  Next, a processing procedure for the semiconductor wafer W in the heat treatment apparatus 1 will be described. The processing procedure of the heat treatment apparatus 1 described below proceeds by the control unit 3 controlling each operation mechanism of the heat treatment apparatus 1.

  First, a gate valve (not shown) is opened to open the transfer opening 67, and a silicon semiconductor wafer W to be processed is transferred into the chamber 6 through the transfer opening 67 by a transfer robot outside the apparatus. The semiconductor wafer W carried in by the carrying robot advances to a position directly above the holding unit 7 and stops. Then, when the pair of transfer arms 51 of the transfer mechanism 5 is raised, a total of four lift pins 52 pass through the through holes of the holding plate 71 and protrude upward from the support pins 72, so that the semiconductor wafer is transferred from the transfer robot. W is received.

  After the semiconductor wafer W is placed on the lift pins 52, the transfer robot moves out of the heat treatment space 65 and the transfer opening 67 is closed, so that the heat treatment space 65 is closed. Then, when the pair of transfer arms 51 are lowered, the semiconductor wafer W is transferred from the transfer mechanism 5 to the holding unit 7 and is held in a horizontal posture from below by the support pins 72. The semiconductor wafer W is held by the holding unit 7 with the surface on which the pattern is formed as the upper surface. That is, the back surface on which no pattern is formed is the lower surface.

  After the semiconductor wafer W is held horizontally from below by the holding unit 7 made of quartz, the 40 halogen lamps HL of the light irradiation unit 4 are turned on all at once, and light irradiation heating (lamp annealing) is performed. Be started. The halogen light emitted from the halogen lamp HL is irradiated from the back surface of the semiconductor wafer W through the quartz window 64 and the holding plate 71 made of quartz.

  The light emitted from the halogen lamp HL and transmitted through the quartz window 64 and the holding plate 71 is irradiated onto the back surface of the semiconductor wafer W held by the holding unit 7, whereby the semiconductor wafer W is heated and targeted processing is performed. Raise to temperature. In this embodiment, since light is irradiated on the back surface of the semiconductor wafer W on which no pattern is formed, uniform light irradiation heating can be performed (so-called backside annealing). In other words, since there is no pattern dependency of the light absorption rate on the back surface of the semiconductor wafer W on which no pattern is formed, the light absorption rate is uniform over the entire back surface, and as a result, the light of the halogen lamp HL is uniformly absorbed. It is. Since the transfer arm 51 and the lift pin 52 of the transfer mechanism 5 are also formed of quartz, there is no obstacle to light irradiation heating by the halogen lamp HL.

  From the semiconductor wafer W that has been heated by light irradiation heating from the halogen lamp HL, infrared rays having an intensity (energy) corresponding to the temperature are emitted. It is known that the intensity of infrared rays emitted from the semiconductor wafer W is proportional to the fourth power of the temperature (absolute temperature) (Stephan-Boltzmann law). Then, the infrared rays radiated from the surface of the semiconductor wafer W whose temperature has been raised pass through a silicon infrared transmission window 63 provided at the upper end of the chamber 6.

  FIG. 6 is a diagram showing the spectral transmittance of silicon having a thickness of 3 mm. As shown in the figure, light having a wavelength of 1 μm or less including visible light does not pass through silicon at all, whereas infrared light having a wavelength of 1 μm or more passes through silicon to some extent. And the pyrometer 81 of this embodiment detects infrared rays with a wavelength of 1 μm or more. Accordingly, infrared rays having a wavelength of 1 μm or more radiated from the surface of the semiconductor wafer W whose temperature has been increased pass through the infrared transmission window 63 of silicon and are detected by the pyrometer 81.

  Radiated light (infrared rays) radiated from the surface of the semiconductor wafer W and transmitted through the infrared transmission window 63 is guided to the light receiving sensor 21 by the wide-angle lens system 82 of the pyrometer 81. At this time, the radiated light radiated from three different regions on the surface of the semiconductor wafer W is individually guided to one of the three light receiving sensors 21 by the wide-angle lens system 82. That is, the three light receiving sensors 21 receive radiated light from three different locations on the semiconductor wafer W.

  FIG. 7 is a view showing three regions of the semiconductor wafer W to be measured by the three light receiving sensors 21. For example, the radiated light emitted from the region SR on the left side in FIG. 7 passes through the infrared transmission window 63 and is then guided to the light receiving sensor 21 on the upper side in FIG. 7 is guided to the light receiving sensor 21 in the center of FIG. 3 by the wide-angle lens system 82. Further, the radiated light emitted from the region SR on the right side of FIG. 7 is guided to the light receiving sensor 21 on the lower side of FIG. As described above, the three light receiving sensors 21 of the pyrometer 81 receive the radiated light from the three different locations of the semiconductor wafer W via the single wide-angle lens system 82 and detect the intensity of the radiated light.

  Since the diaphragm 83 is provided in the second lens of the wide-angle lens system 82, it is possible to prevent the radiated light radiated from different regions SR of the semiconductor wafer W from mixing and entering the light receiving sensor 21. That is, only the radiated light radiated from one place in the different region SR of the semiconductor wafer W is guided to each of the three light receiving sensors 21 by the single wide-angle lens system 82. In addition, since the pyrometer 81 includes the wide-angle lens system 82, the radiation light from three different regions in a wide range of the semiconductor wafer W can be guided to the light receiving sensor 21.

  Each of the three light receiving sensors 21 that have received the radiated light emitted from the three regions SR on the surface of the semiconductor wafer W each outputs an electric signal having a level corresponding to the intensity of the received radiated light. The electrical signals output from the three light receiving sensors 21 are sequentially selected by the multiplexer 85, and the signal from one of the light receiving sensors 21 is transmitted to the temperature calculation unit 91. In the temperature calculation unit 91, the signal output from the light receiving sensor 21 selected by the multiplexer 85 is converted into a digital signal by the A / D converter 25. Then, the calculation unit 93 performs calculation processing based on the digital signal, whereby the temperature of the region SR of the semiconductor wafer W corresponding to the selected light receiving sensor 21 is calculated. In order to calculate the temperature from the intensity of the radiated light of the semiconductor wafer W, a known calculation method using Planck's law for black body radiation or Stefan-Boltzmann law derived therefrom can be used. Further, a table in which the surface temperature of the semiconductor wafer W and the signal level output from the light receiving sensor 21 are associated in advance is created and stored in a storage unit provided in the control unit 3, and the temperature of the region SR is based on the table. May be requested.

  Since the multiplexer 85 sequentially selects the electrical signals input from the three light receiving sensors 21 and outputs them to one temperature calculation unit 91, the calculation unit 93 outputs the signals from the three light receiving sensors 21. It processes sequentially and calculates the temperature of three area | regions SR sequentially.

  In this way, in the present embodiment, three light receiving sensors 21 are provided in one pyrometer 81, and the temperatures of three regions SR on the surface of the semiconductor wafer W are measured by the single pyrometer 81. The temperatures of the three regions SR calculated by the temperature calculation unit 91 are transmitted to the control unit 3. The control unit 3 may control power supply to the halogen lamp HL of the light irradiation unit 4 based on the calculation result by the temperature calculation unit 91 so that the temperatures of the three regions SR are equal. Further, the control unit 3 may display the temperature calculation results of the three regions SR by the temperature calculation unit 91 on a display or the like.

  By the way, at the time of temperature measurement as described above, a part of the light emitted from the semiconductor wafer W is transmitted through the infrared transmission window 63, but the rest is absorbed by the infrared transmission window 63, and the infrared transmission window 63 itself is Heated. That is, the infrared transmission window 63 made of the same material (silicon) as the semiconductor wafer W is heated by the radiant heat from the semiconductor wafer W that has been heated by light irradiation heating. Silicon exhibits spectral transmittance characteristics as shown in FIG. 6 at room temperature, but has a property that it hardly transmits infrared rays when heated and heated. Therefore, as the elapsed time from the temperature rise of the semiconductor wafer W becomes longer, the infrared transmission window 63 also rises in temperature, and the infrared rays radiated from the semiconductor wafer W do not easily pass through the infrared transmission window 63, and the pyrometer 81. Detection by is difficult.

  Therefore, a cooling unit 69 for cooling the infrared transmission window 63 is provided. The cooling unit 69 continuously blows air toward the upper surface of the infrared transmission window 63 at least while the halogen lamp HL is lit. Thereby, even if the temperature of the semiconductor wafer W is increased by light irradiation heating from the halogen lamp HL, the temperature of the infrared transmission window 63 is maintained at 150 ° C. or less by the cooling unit 69. If it is 150 degrees C or less, the infrared transmission window 63 can permeate | transmit infrared rays with a wavelength of 1 micrometer or more. In order to transmit infrared rays more reliably, it is preferable to cool the infrared transmission window 63 to 100 ° C. or less by the cooling unit 69.

  After the light irradiation heating for a predetermined time is completed, the halogen lamp HL is turned off and the temperature lowering of the semiconductor wafer W is started. After the halogen lamp HL is turned off and a predetermined time has passed and the semiconductor wafer W has sufficiently cooled down, the pair of transfer arms 51 of the transfer mechanism 5 is raised, and the semiconductor in which the lift pins 52 are held by the holding plate 71. The wafer W is pushed up and separated from the support pins 72. Thereafter, the transfer opening 67 is opened again, and the hand of the transfer robot outside the apparatus enters the chamber 6 through the transfer opening 67 and stops just below the semiconductor wafer W. Subsequently, when the transfer arm 51 is lowered, the semiconductor wafer W is transferred from the lift pins 52 to the transfer robot. Then, when the hand of the transfer robot that has received the semiconductor wafer W leaves the chamber 6, the semiconductor wafer W is unloaded from the chamber 6, and the light irradiation heating process in the heat treatment apparatus 1 is completed.

  In the present embodiment, three light receiving sensors 21 are provided in one pyrometer 81. Then, a single wide-angle lens system 82 is provided for these three light receiving sensors 21, and radiated light emitted from three different regions SR of the semiconductor wafer W is transmitted by the single wide-angle lens system 82. The light receiving sensor 21 is led individually. Signals output from the three light receiving sensors 21 that have received the radiated light emitted from the three different regions SR are sequentially processed by the temperature calculation unit 91, and the temperatures of the three regions SR are obtained. For this reason, it is possible to eliminate machine differences due to the distance from the measurement target region to the pyrometer 81, the installation angle of the pyrometer 81, the lens system included in the pyrometer 81, and the like (there is no machine difference in the first place), and the semiconductor wafer The temperatures of the three regions SR having different W can be accurately measured in a non-contact manner.

  Further, the three light receiving sensors 21 are accommodated in a single holder 25. The holder 25 is cooled to a predetermined temperature by a Peltier element 27. Therefore, the three light receiving sensors 21 housed in the common holder 25 are uniformly cooled to the same temperature. For this reason, the thermal noise due to the temperature of the light receiving sensor 21 itself is exactly the same for the three light receiving sensors 21. As a result, there is no machine difference due to the thermal noise of the light receiving sensor 21, and the temperatures of the three regions SR of the different semiconductor wafers W can be measured more accurately.

  Further, the electrical signals output from the three light receiving sensors 21 are sequentially selected by the multiplexer 85 and transmitted to the temperature calculation unit 91, whereby the signals from the three light receiving sensors 21 are shared by the common A / D converter 25. And it will be processed by the calculating part 93. For this reason, there is no machine difference caused by the electric circuit that processes the electric signal output from the light receiving sensor 21. As a result, once the adjustment by the electric circuit of the temperature calculation unit 91 is performed, the measurement accuracy of the three light receiving sensors 21 is uniform.

  Thus, in this embodiment, the temperature of several different places of the semiconductor wafer W can be measured accurately by eliminating the machine difference of the pyrometer. In addition, it is possible to minimize the burden required to eliminate the difference between the pyrometers, which has conventionally been a complicated operation.

  While the embodiments of the present invention have been described above, the present invention can be modified in various ways other than those described above without departing from the spirit of the present invention. For example, in the above embodiment, the light irradiation unit 4 is provided below the chamber 6 and backside annealing is performed by irradiating and heating the back surface of the semiconductor wafer W. However, the light irradiation unit is disposed above the chamber 6. 4 may be provided to irradiate the surface of the semiconductor wafer W on which the pattern is formed. Moreover, the temperature measuring unit 8 according to the present invention may be provided in a flash lamp annealing apparatus in which the light irradiation unit 4 provided with the halogen lamp HL is provided below the chamber 6 and the flash lamp is provided above the chamber 6. .

  When the lamp is provided above the chamber 6, the pyrometer 81 of the temperature measuring unit 8 is installed obliquely above the semiconductor wafer W to be measured so as not to obstruct light irradiation. Even if the pyrometer 81 is installed obliquely above the semiconductor wafer W, the radiated light emitted from different locations on the semiconductor wafer W is individually guided to the three light receiving sensors 21 by the single wide-angle lens system 82, The temperature at multiple locations can be measured accurately.

  In the above embodiment, the three light receiving sensors 21 are provided in the pyrometer 81. However, the present invention is not limited to this, and any configuration may be used as long as a plurality of light receiving sensors 21 are provided. FIG. 8 shows an external perspective view of a holder 125 provided with seven light receiving sensors 21. The holder 125 of FIG. 8 has seven storage holes formed therein, and one light receiving sensor 21 is stored in each hole. The configuration of the pyrometer 81 is the same as that in the above embodiment except that the seven light receiving sensors 21 are housed in the holder 125.

  FIG. 9 is a diagram illustrating seven regions of the semiconductor wafer W to be measured by the seven light receiving sensors 21. In the example of FIG. 9, a pyrometer 81 is installed obliquely above the semiconductor wafer W. When the pyrometer 81 is installed obliquely above the semiconductor wafer W, each measurement region is substantially oval as shown in FIG. Even in this case, the emitted light emitted from seven different regions of the semiconductor wafer W is individually guided to the seven light receiving sensors 21 by the single wide-angle lens system 82. Then, the signals output from the seven light receiving sensors 21 that receive the radiated light emitted from the seven different regions are sequentially processed by the temperature calculating unit 91, and the temperatures of the seven regions are accurately measured. . When the wide-angle lens system 82 is cylindrical, it is preferable to provide a cylindrical holder 125 that houses seven light receiving sensors 21 as shown in FIG.

  Further, two or more pyrometers 81 may be provided in one heat treatment apparatus 1. FIG. 10 is a diagram illustrating an example of a configuration in which two pyrometers 81 similar to those in the above embodiment are provided. In the example shown in FIG. 10, two pyrometers 81 are provided obliquely above the semiconductor wafer W with an interval of 90 °. Each pyrometer 81 measures the temperature of three different regions of the semiconductor wafer W. As shown in the figure, the central region of the three regions where the two pyrometers 81 measure the temperature overlap each other. One of the two pyrometers 81 is a master and the other is a slave, and the temperature of the central region measured by the slave pyrometer 81 matches the temperature of the central region measured by the master pyrometer 81. Adjust the electrical circuit. In this way, the temperatures of five different regions of the semiconductor wafer W can be accurately measured using the two pyrometers 81.

Moreover, in the said embodiment, although the infrared transmission window 63 was formed with the silicon | silicone, it is not limited to this, What is necessary is just the material which permeate | transmits the infrared rays of the detection wavelength range of the pyrometer 81, for example, germanium (Ge) or may be formed of sapphire _(Al 2 _{O 3).} However, since silicon discs can be obtained relatively easily, it is preferable to use silicon from the viewpoint of manufacturing cost. Moreover, if the light irradiation from the light irradiation part 4 does not become disturbance, you may make it form the infrared transmission window 63 with quartz glass.

  Further, the infrared transmission window 63 may be cooled by water instead of air cooling. Even when the infrared transmission window 63 is cooled by water cooling, the infrared transmission window 63 is cooled to 150 ° C. or less through which infrared rays radiated from the semiconductor wafer W pass.

  Further, the pyrometer 81 may be installed below or obliquely below the semiconductor wafer W to measure the temperatures at a plurality of different locations on the back surface of the semiconductor wafer W.

  The substrate to be processed by the heat treatment apparatus according to the present invention is not limited to a semiconductor wafer, and may be a glass substrate or a solar cell substrate used for a flat panel display such as a liquid crystal display device. Further, the object to be measured by the temperature measuring unit 8 which is the temperature measuring device according to the present invention is not limited to a semiconductor wafer or a glass substrate. It may be a material (for example, a high-temperature metal plate or ceramic).

DESCRIPTION OF SYMBOLS 1 Heat processing apparatus 3 Control part 4 Light irradiation part 5 Transfer mechanism 6 Chamber 7 Holding part 8 Temperature measurement part 21 Light receiving sensor 25 Holder 27 Peltier element 63 Infrared transmission window 64 Quartz window 65 Heat treatment space 69 Cooling part 71 Holding plate 72 Support Pin 81 Pyrometer 82 Wide-angle lens system 83 Aperture 85 Multiplexer 91 Temperature calculation unit 92 A / D converter 93 Calculation unit HL Halogen lamp W Semiconductor wafer

Claims (6)

A temperature measuring device that measures the temperature of a plurality of locations of a substrate in a non-contact manner,
A plurality of light receiving sensors for receiving radiation emitted from the substrate;
A single lens system for individually guiding radiated light emitted from a plurality of locations of the substrate to any of the plurality of light receiving sensors;
A temperature calculation unit that individually calculates the temperatures of the plurality of locations based on the intensity of radiated light received by each of the plurality of light receiving sensors;
With
The temperature measuring device according to claim 1, wherein radiation light emitted from one of the plurality of locations is guided to each of the plurality of light receiving sensors by the single lens system. The temperature measuring device according to claim 1,
A single storage section for storing the plurality of light receiving sensors;
A cooling unit for cooling the single storage unit;
The temperature measuring device further comprising: In the temperature measuring device according to claim 1 or 2,
The temperature calculation unit includes a common arithmetic circuit that calculates a temperature by sequentially processing signals from the plurality of light receiving sensors. In the temperature measuring device according to any one of claims 1 to 3,
The temperature measuring apparatus, wherein the single lens system is a wide-angle lens system. A chamber for housing the substrate;
A heating unit for heating the substrate accommodated in the chamber;
The temperature measuring device according to any one of claims 1 to 4, which measures the temperature of a plurality of locations on the substrate heated by the heating unit;
A heat treatment apparatus comprising: The heat treatment apparatus according to claim 5, wherein
The heating unit includes a lamp that irradiates light to a substrate accommodated in the chamber to heat the substrate.

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