JP2009236631A - Temperature measurement apparatus, mounting platform structure having the same, and heat treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a temperature measurement apparatus preventing a metal contamination, and drastically improving the measurement accuracy of a temperature, by placing a diffraction grating in an measuring object. <P>SOLUTION: The temperature measurement apparatus 50 for measuring the temperature of the measuring object 42 comprises: the diffraction grating 68 formed in the measuring object; a light emitting section 75 for generating a measurement light L1 for measuring the temperature; a first optical waveguide 70A-1(70) for guiding the measurement light to the diffraction grating; a second optical waveguide 70A-2(70) for guiding a diffraction light from the diffraction grating; a frequency analysis section 78 for receiving the diffraction light guided by the second light waveguide, and analyzing a frequency; and a temperature analysis section 80 for obtaining the temperature of the measuring object, based on an output from the frequency analysis section. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a temperature measuring device for heat-treating an object to be processed such as a semiconductor wafer, a mounting table structure and a heat treatment device using the same.

In general, in order to manufacture a semiconductor integrated circuit, it is desired to repeatedly perform various single wafer processes such as a film forming process, an etching process, a heat treatment, a modification process, and a crystallization process on a target object such as a semiconductor wafer. An integrated circuit is formed. When performing various processes as described above, a necessary processing gas corresponding to the type of the process, for example, a film forming gas or a halogen gas in the case of a film forming process, and an ozone gas in the case of a reforming process. In the case of crystallization treatment, an inert gas such as N ₂ gas or O ₂ gas is introduced into the treatment container.

  For example, in the case of a single wafer processing apparatus that performs heat treatment on each semiconductor wafer, for example, a mounting table with a built-in resistance heater is installed in a processing container that can be evacuated. A semiconductor wafer is placed on the upper surface, and the temperature of the wafer is measured by a temperature sensor, and a predetermined process gas is flowed in a state heated at a predetermined temperature (for example, 100 ° C. to 1000 ° C.), under predetermined process conditions Various heat treatments are performed on the wafer (Patent Documents 1 to 6).

  In this case, it is very important to maintain the wafer temperature accurately at a desired temperature during the heat treatment in order to maintain high quality of the heat treatment on the wafer surface.

  In the conventional temperature measurement method, since a temperature sensor cannot be provided directly on the wafer, a temperature sensor is provided on the back side of the mounting table that supports the wafer (the side opposite to the top surface on which the wafer is mounted). A temperature measuring resistor whose resistance value changes depending on the temperature of a thermocouple, platinum, or the like, or a contact type temperature sensor such as Fiber Bragg Grating (FBG) is provided to indirectly measure the wafer temperature or radiation temperature. The wafer temperature was measured by observing the intensity of a specific wavelength of infrared light emitted from the semiconductor wafer using a meter.

Japanese Patent Laid-Open No. 06-260430 JP 2004-319537 A JP 2004-356624 A JP 2006-295138 A JP 2007-113103 A JP 2007-141895 A

  By the way, regarding the temperature sensor as described above, in the case of a contact type temperature sensor such as a thermocouple or a resistance temperature detector, it is avoided that a slight minute space is generated between the temperature sensor and the mounting table. For this reason, when heat treatment is performed in a high vacuum environment, the heat conduction by the gas is not sufficient, and the accuracy of the measurement temperature may be reduced. Further, the semiconductor wafer itself may be exposed to metal contamination by the metal constituting the thermocouple.

  The FBG described above forms a diffraction grating in the core of an optical fiber and measures the temperature by giving it a function as an optical filter. However, the FBG has a thermal resistance to heat conduction in the cross-sectional direction of the optical fiber. In this case, there is a problem that the accuracy of temperature measurement is lowered. In addition, as described above, the structure of the FBG is complicated, so that it is relatively expensive.

  In the case of a radiation thermometer, since it is a non-contact type temperature sensor, there is no problem of metal contamination, but there is a problem that the temperature measurement accuracy is low compared to the above-described temperature sensors. .

  The present invention has been devised to pay attention to the above problems and to effectively solve them. SUMMARY OF THE INVENTION An object of the present invention is to provide a temperature measuring device capable of greatly improving the temperature measurement accuracy without causing metal contamination by providing a diffraction grating on the object to be measured, a mounting table structure and a heat treatment device having the temperature measuring device. Is to provide.

  The invention according to claim 1 is the temperature measuring device for measuring the temperature of the measurement object, the diffraction grating formed on the measurement object, the light emitting unit for generating the measurement light for temperature measurement, and the measurement light A first optical waveguide that leads to the diffraction grating, a second optical waveguide that guides the diffracted light from the diffraction grating, and a frequency analyzer that receives the diffracted light guided by the second optical waveguide and analyzes the frequency And a temperature analysis unit that obtains the temperature of the object to be measured based on the output of the frequency analysis unit.

  In this way, it is possible to generate the diffracted light by irradiating the diffraction grating formed on the measured object with the measurement light, and obtain the temperature of the measured object based on the diffracted light from the diffraction grating. Therefore, by providing the diffraction grating on the object to be measured in this way, the temperature measurement accuracy can be greatly improved without causing metal contamination.

In this case, for example, as described in claim 2, the diffraction grating is directly formed on the surface of the measurement object.
For example, as described in claim 3, the diffraction grating is formed on an inner surface of a hole formed in the measurement object.
Further, for example, as described in claim 4, the first optical waveguide and the second optical waveguide are fixed at a fixed angle with respect to the diffraction grating.

For example, as described in claim 5, the first optical waveguide and the second optical waveguide are integrally joined.
Further, for example, as described in claim 6, the first optical waveguide and the second optical waveguide are shared by a single optical waveguide, and the diffracted light is placed in the middle of the combined optical waveguide. Is provided.

For example, as described in claim 7, the first optical waveguide and the second optical waveguide are accommodated in a protective tube.
For example, as described in claim 8, the measurement light is modulated.
For example, as described in claim 9, the measurement light is a broadband light having a certain frequency width.
For example, as described in claim 10, the broadband light is white light.

  According to an eleventh aspect of the present invention, there is provided a mounting table having a mounting plate made of an opaque material on which the object to be processed is mounted in order to perform a predetermined heat treatment on the object to be processed in a processing container that can be evacuated. A mounting table structure characterized by having the temperature measuring device according to any one of claims 1 to 10 and a diffraction grating of the temperature measuring device provided on the mounting plate. It is.

In this case, for example, as described in claim 12, the diffraction grating is formed on the back surface of the mounting plate.
For example, as described in claim 13, the diffraction grating is formed on the inner surface of the hole formed in the mounting plate.
For example, as described in claim 14, the mounting plate is made of opaque quartz glass or an opaque ceramic material.

Further, for example, as described in claim 15, the mounting plate is provided on a mounting table main body supported by a support column.
Further, for example, as described in claim 16, the mounting plate is supported by a plurality of support rods extending from the upper end portion of a cylindrical column whose inner diameter is larger than that of the mounting plate. .

  According to a seventeenth aspect of the present invention, there is provided a heat treatment apparatus for performing a predetermined heat treatment on an object to be processed, a processing container that can be evacuated, a gas supply unit that supplies a predetermined gas into the processing container, The mounting table structure according to any one of Items 11 to 16, a heating unit that heats the object to be processed mounted on the mounting table structure, and a measurement value of a temperature measuring device provided in the mounting table structure And a temperature control unit for controlling the heating means based on the heat treatment apparatus.

According to the temperature measuring device, the mounting table structure, and the heat treatment device having the same according to the present invention, the following excellent operational effects can be exhibited.
It is possible to generate a diffracted light by irradiating the diffraction grating formed on the measured object with the measuring light, and obtain the temperature of the measured object based on the diffracted light from the diffraction grating. Therefore, by providing the diffraction grating on the object to be measured in this way, the temperature measurement accuracy can be greatly improved without causing metal contamination.

Hereinafter, a preferred embodiment of a temperature measuring device, a mounting table structure and a heat treatment device using the same according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a sectional view showing a heat treatment apparatus having a mounting table structure using a temperature measuring device according to the present invention, FIG. 2 is an enlarged view showing a part of the mounting table structure provided with the temperature measuring device, and FIG. 4 is a plan view showing an example of the diffraction grating provided on the lower surface of the mounting plate, FIG. 4 is an explanatory diagram for explaining the state of the diffracted light by the diffraction grating, and FIG. It is a figure which shows the state of the diffracted light when it is made to perform. Here, a case where the temperature of a mounting plate on which a semiconductor wafer is mounted is measured as an object to be measured by a temperature measuring device as an object to be measured will be described as an example.

  As shown in FIG. 1, the heat treatment apparatus 2 includes an aluminum processing vessel 4 having a substantially circular cross section. A shower head portion 6 serving as a gas supply means is provided on the ceiling portion in the processing vessel 4 to introduce a necessary processing gas, for example, a film forming gas. The process gas is ejected from the gas injection holes 10A and 10B toward the process space S.

  In the shower head portion 6, gas diffusion chambers 12A and 12B divided into two hollow shapes are formed. After the processing gas introduced therein is diffused in the plane direction, each gas diffusion chamber 12A is formed. , 12B are blown out from the respective gas injection holes 10A, 10B communicated with each other. That is, the gas injection holes 10A and 10B are arranged in a matrix. The entire shower head portion 6 is made of, for example, a nickel alloy such as nickel or Hastelloy (registered trademark), aluminum, or an aluminum alloy. The shower head unit 6 may have one gas diffusion chamber.

  A sealing member 14 made of, for example, an O-ring or the like is interposed at the joint between the shower head 6 and the processing container 4 so that the airtightness in the processing container 4 is maintained.

  In addition, a loading / unloading port 16 for loading / unloading a semiconductor wafer W as an object to be processed into / from the processing container 4 is provided on the side wall of the processing container 4, and the loading / unloading port 16 can be opened and closed in an airtight manner. A gate valve 18 is provided.

  And the center part of the bottom part 20 of this processing container 4 is depressed below in the shape of a recessed part, and the exhaust chamber 22 is provided. An exhaust port 24 is provided in a side wall that defines the exhaust chamber 22. An exhaust system 26 for exhausting the inside of the processing container 4 is connected to the exhaust port 24. The exhaust system 26 has an exhaust passage 28 connected to the exhaust port 24, and a pressure regulating valve 30 and an exhaust pump 32 are sequentially provided in the exhaust passage 28. The desired pressure can be maintained. In this case, the inside of the processing container 4 is set to a wide pressure from high vacuum to about atmospheric pressure according to the processing mode.

  A mounting table structure 36 is provided on the bottom 34 defining the exhaust chamber 22 in the processing container 4 so as to stand up. Specifically, the mounting table structure 36 includes a mounting table 38 on which a semiconductor wafer W as an object to be processed is mounted, and a hollow cylindrical column 39 erected from the bottom 34 to support the mounting table 38. And is mainly composed. The mounting table 38 includes a mounting table main body 40 and a mounting plate 42 mounted on the mounting table main body 40 and in direct contact with the back surface of the wafer W.

  In the mounting table main body 40, a resistance heater 46 made of, for example, a carbon heater disposed in a predetermined pattern shape is embedded as the heating means 44, for example. The resistance heater 46 is electrically divided into, for example, an inner zone 46A and an outer zone 46B that concentrically surrounds the outer zone 46A, and the power can be individually controlled for each zone. The resistance heater 46 in each zone is connected with two power supply rods 48 for supplying electric power, and the power supply rods 48 are actually connected to the two zones of the inner zone 46A and the outer zone 46B. 4 are provided, but only two are shown in the illustrated example. The power feed rod 48 is connected to a heater power source 49 to supply power.

Here, the support column 39 and the mounting table main body 40 are made of a heat-resistant material such as a ceramic material such as aluminum nitride or quartz glass, and the tip end portion of the support column 39 is welded, for example, to the center of the lower surface of the mounting table body 40. . The inside of the support column 39 is sealed, and the inside of the support column 39 is filled with a rare gas such as Ar gas or an inert gas such as N ₂ gas.

  The mounting plate 42 is made of an opaque material that has heat resistance and does not contaminate the wafer W. Specifically, as this opaque material, opaque aluminum nitride (AlN), silicon carbide (SiC), opaque quartz glass containing bubbles, or the like can be used. The mounting plate 42 has a function as a heat equalizing plate that diffuses heat from the resistance heater 46 in the plane direction, and heats the wafer W at a uniform temperature in the in-plane direction. .

  The diameter of the mounting plate 42 is set to be slightly larger than the diameter of the wafer W, and the thickness thereof is in the range of about 2 to 10 mm, for example, depending on the type of processing. The mounting table structure 36 is provided with the temperature measuring device 50 for a measurement object according to the present invention. The temperature measuring device 50 will be described later.

  The mounting table 38 is formed with a plurality of, for example, three pin insertion holes 52 penetrating in the vertical direction (only two are shown in FIG. 1). A push-up pin 54 that is movably inserted in a loosely fitted state is disposed. At the lower end of the push-up pin 54, a push-up ring 56 made of a ceramic such as alumina having a circular ring shape is disposed, and the lower end of each push-up pin 54 is on the push-up ring 56.

  The arm portion 58 extending from the push-up ring 56 is connected to a retracting rod 60 provided through the container bottom portion 20, and the retracting rod 60 can be moved up and down by an actuator 62. As a result, the push-up pins 54 are projected and retracted upward from the upper ends of the pin insertion holes 52 when the wafer W is transferred. In addition, an extendable bellows 64 is interposed in the through-hole portion of the bottom of the retractable rod 60 of the actuator 62 so that the retractable rod 60 can be raised and lowered while maintaining the airtightness in the processing container 4. ing.

  Here, the temperature measuring device 50 provided in the mounting table structure 36 will be described. Here, the mounting plate 42 corresponds to the object to be measured by the temperature measuring device 50, and the temperature of the mounting plate 42 is accurately measured. Since the mounting plate 42 is simply placed on the mounting table main body 40, when viewed microscopically, as shown in FIG. 2, the upper surface of the mounting table main body 40 and the mounting plate 42. A slight gap 66 is partially generated between the lower surface of the first and second surfaces.

  Since the inner zone 46A and the outer zone 46B of the mounting plate 42 are separately controlled here, the temperature measuring device 50 having the same structure is provided for each of the zones 46A and 46B. In some cases, the number of zones is 1 or 3 or more.

  Specifically, the temperature measuring device 50 has diffraction gratings 68 provided corresponding to the zones 46A and 46B on the back surface (lower surface) of the mounting plate 42, that is, diffraction gratings 68A and 68B. . The grating grooves 69 (see FIG. 3) of the diffraction gratings 68A and 68B are directly formed on the back surface of the mounting plate 42 by optical processing such as laser light or mechanical processing. The interval (lattice constant) d between the lattice grooves 69 is about several μm.

  Each of the diffraction gratings 68A and 68B is provided with a single optical waveguide 70, that is, each tip of the optical waveguides 70A and 70B facing each other. Each of the optical waveguides 70A and 70B is made of an optical fiber, is inserted through the insertion holes 72A and 72B formed in the mounting table main body 40, and is fixed so that the tip end faces the diffraction gratings 68A and 68B. .

  Here, the insertion holes 72A and 72B are provided so as to be inclined by a certain angle α with respect to the thickness direction of the mounting table main body 40, and the diffraction gratings 68A and 68B are irradiated with measurement light from an oblique direction. It is like that. The optical waveguides 70 </ b> A and 70 </ b> B are inserted into the hollow support column 39 and extend below the bottom 34 of the exhaust chamber 22. In the support column 39, the optical waveguides 70A and 70B are passed through protective tubes 74A and 74B such as quartz glass tubes. The base end portions of the optical waveguides 70A and 70B are commonly connected to the light emitting unit 75 that generates the measurement light.

  The light emitting unit 75 outputs broadband light having a certain frequency width, for example, white light, as the measurement light. In order to facilitate detection of diffracted light, it is preferable to modulate the measurement light.

  Here, each of the optical waveguides 70A and 70B has one function of guiding the measurement light for temperature measurement to the diffraction gratings 68A and 68B and one function of receiving and guiding the diffracted light from the diffraction gratings 68A and 68B. It is also used as an optical waveguide. Therefore, a spectroscope 76, that is, spectroscopes 76A and 76B, is provided in the middle of the optical waveguides 70A and 70B, respectively, so that the diffracted light returning from the diffraction gratings 68A and 68B can be separated. ing. Each separated diffracted light is input to the frequency analysis unit 78, that is, the frequency analysis units 78A and 78B, where the frequency is analyzed and subjected to photoelectric conversion.

  The frequency analysis units 78A and 78B are connected to a temperature analysis unit 80, that is, temperature analysis units 80A and 80B, respectively, so as to obtain the temperature of the mounting plate 42 in accordance with the variation in the frequency of each diffracted light. It has become. The outputs of the temperature analysis units 80A and 80B are input to the temperature control unit 82. The temperature control unit 82 controls the heater power supply 49 so as to maintain a predetermined temperature for each zone. It has become.

  The overall operation of the heat treatment apparatus 2, for example, control of the process pressure, temperature control of the mounting table 38, supply and stop of supply of the processing gas, and the like are performed by the apparatus control unit 84 formed of, for example, a computer. The device control unit 84 has a storage medium 86 for storing a computer program necessary for the above operation. The storage medium 86 includes a flexible disk, a CD (Compact Disc), a hard disk, a flash memory, or the like.

Next, the operation of the heat treatment apparatus configured as described above will be described.
First, the unprocessed semiconductor wafer W is loaded into the processing container 4 through the gate valve 18 and the loading / unloading port 16 which are held by a transfer arm (not shown) and opened, and this wafer W is pushed up. After being transferred to the pins 54, the push-up pins 54 are lowered to place the wafer W on the upper surface of the mounting plate 42 of the mounting table structure 36 and support it.

  Next, various processing gases are supplied to the shower head unit 6 while controlling the flow rate, and the gases are blown out from the gas injection holes 10A and 10B and introduced into the processing space S. Then, by continuing to drive the exhaust pump 32 of the exhaust system 26, the atmosphere in the processing container 4 is evacuated, for example, and the opening degree of the pressure regulating valve 30 is adjusted to adjust the atmosphere of the processing space S. Maintain a predetermined process pressure. At this time, the temperature of the wafer W is maintained at a predetermined process temperature.

  That is, the resistance heating heater 46 constituting the heating means 44 provided on the mounting table body 40 of the mounting table structure 36 is heated by applying a voltage from the heater power supply 49 side through the power supply rod 48 and is measured. The temperature of the mounting plate 42, which is a body, is accurately measured by the temperature measuring device 50 according to the present invention, and the temperature of the mounting plate 42 is controlled on the basis of this, so the upper surface of the mounting plate 42 The temperature of the wafer W placed on the substrate can be controlled with high accuracy and the uniformity of the in-plane temperature can be controlled.

  That is, the white light that is the measurement light output from the light emitting unit 75 is guided through each of the optical waveguides 70A and 70B made of an optical fiber, and is emitted from the tip thereof. The emitted measurement light L1 (see FIG. 4) is incident on the diffraction gratings 68A and 68B of the zones 46A and 46B, and is diffracted thereby to reflect the diffracted light.

  In this case, since the mounting plate 42 thermally expands and contracts depending on the temperature, the interval (the number of grating holes) d of the diffraction gratings 68A and 68B changes depending on the respective temperatures, thereby each optical waveguide 70A. , 70B, the frequency of the diffracted light entering 70B changes. The diffracted light incident on the optical waveguides 70A and 70B returns to the optical waveguides 70A and 70B, and the diffracted light is extracted by the spectroscopes 76A and 76B, respectively. The diffracted light extracted here is subjected to frequency analysis of the diffracted light by the frequency analyzers 78A and 78B, respectively, and the result is input to the temperature analyzers 80A and 80B.

  The temperature analysis units 80A and 80B have frequency data serving as a reference corresponding to the temperature in advance, and by comparing the frequency data with the analysis results sent from the frequency analysis units 78A and 78B, The temperature of the mounting plate 42 for each zone can be obtained with high accuracy. Then, the measured value of the temperature of the mounting plate 42 obtained here is input to the temperature control unit 82, and based on this, the heater power supply 49 is controlled so that the temperature of the mounting plate 42 becomes a predetermined temperature. It will be.

  Here, the state of the diffracted light in the diffraction grating will be described with reference to FIGS. FIG. 4 is an explanatory diagram for explaining the state of diffracted light by the diffraction grating, and FIG. 5 is a diagram showing the state of diffracted light when measurement light is emitted and diffracted light is incident on the same optical waveguide. FIG. 4A shows a state of monochromatic light diffraction, and FIG. 4B shows a state of white light diffraction. FIG. 5 also shows an example of the diffraction state in a minute region of the diffraction grating as an enlarged view. Here, a diffraction grating 68A provided in the inner zone 46A, which is one diffraction grating in FIG. 2, will be described as an example. Needless to say, the same applies to the diffraction grating 68B of the outer zone 46B.

  In FIG. 4A, when monochromatic light having an incident angle α (angle with respect to the normal line 90) with respect to the normal line 90 of the mounting plate 42 enters the diffraction grating 68A, diffracted light is generated. Here, for simplification of explanation, only diffracted light of + 1st order light and −1st order light is shown. The diffraction angle of the + 1st order diffracted light with respect to the normal 90 is β1 ′, and the diffraction angle of the −1st order diffracted light with respect to the normal 90 is β1. The zero-order light is reflected in the specular reflection direction 92 according to the law of reflection.

  In FIG. 4B, white light is incident. In this case, since the white light has a certain frequency width (red to purple), the diffraction angles of the −1st order and + 1st order diffracted lights are shown. Both have a certain width. Actually, diffracted light of ± 2nd order or higher is also generated.

  Here, the situation when the optical waveguide 70A made of an optical fiber is actually installed will be described. As shown in FIG. 5, when the measurement light L1 made of white light is radiated from the optical waveguide 70A made of an optical fiber toward the diffraction grating 68A, the diffracted light is reflected from the diffraction grating 68A. Here, the measurement light L1 is incident in parallel to the main section of the diffraction grating 68A (a plane perpendicular to the grating groove 69), and the incident angle is α (an angle with respect to the normal line 90). Here, a lot of diffracted light is generated such as first order, second order, third order, and so on.

  Then, with the specular reflection direction 92 (the angle with respect to the normal is α) as the center, the diffracted light is generated to spread from side to side as primary, secondary, tertiary, etc., and the direction of specular reflection Diffracted light on the same side as the measurement light L1 with respect to 92 becomes “+”, and diffracted light on the opposite side becomes “−”. Therefore, “+ 1st order”, “+ 2nd order”, “+ 3rd order”... Diffracted light is sequentially generated from the mirror reflection direction 92 toward the left side, and “−1st order”, “to the right side”. Second order diffracted light, third order diffracted light are sequentially generated.

  Since the measurement light L1 is white light, the diffraction angle of each diffracted light has a certain spread as described above. Here, for example, the diffraction angle of the −1st order diffracted light is β1, the diffraction angle of the + 1st order diffracted light is β1 ′, the diffraction angle of the −2nd order diffracted light is β2, and the + 2nd order diffracted light. Has a diffraction angle of β2 ′, a diffraction angle of −3rd order diffracted light is β3, and a diffraction angle of + 3rd order diffracted light is β3 ′.

Under the above conditions, the main maximum of the intensity of the diffracted light having the wavelength λ occurs in the direction of the diffraction angle β that satisfies the following expression. Note that the diffraction angle β represents the β1, β1 ′, β2, β2 ′, β3, β3 ′, and the like.
d (sin α + sin β) = mλ (m = 0, ± 1, ± 2...)
Here, since diffracted light is incident and detected by the optical waveguide 70A, “+ third order” diffracted light is used as a measurement target. In this case, since the optical waveguide 70A is fixed, when the pitch of the diffraction grating 68A changes due to thermal expansion and contraction, the frequency of light incident on the optical waveguide 70A changes.

  In the case shown in FIG. 5, a specific frequency within the frequency width of the + 3rd order diffracted light is incident at an angle β. Further, d is known and “m = 3”. Further, since the wavelength λ0 of the wavelength of the diffracted light at a room temperature, for example, which is a known reference temperature, is obtained in advance, if the wavelength λ of the diffracted light at an unknown temperature is obtained, this and the mounting plate 42 are obtained. From the linear expansion coefficient of the constituent material, the temperature at that time can be obtained with high accuracy. In this case, the order of the diffracted light to be measured may be any order of diffracted light. Specifically, the angle α is attached and fixed in the range of “0 degrees <α <90 degrees”. Can do.

Here, the relationship will be described with specific numerical examples. First, it is assumed that the angle formed by the optical waveguide with respect to the normal line of the diffraction grating 90 is α and the diffracted light is incident on the same optical waveguide as the measurement light (α = β).
Suppose that α = 30 degrees with respect to a diffraction grating created on AlN [aluminum nitride] (expansion coefficient: 5.6 × 10 ⁻⁶ ) so that the pitch d between the diffraction gratings is 0.42 μm at room temperature. When white light is incident from the fixed optical waveguide, the primary light of the blue-violet light with a wavelength of 420 nm satisfies the condition that the diffraction angle β = −30 degrees, and thus the reflected light with a wavelength of 420 nm is detected by the frequency analysis unit 78A.

Here, when the temperature of the diffraction grating rises by 100 ° C., d increases by 2.18 × 10 ⁻⁵ μm, so that the diffracted light satisfying the condition of β = −30 degrees is displaced to the long wavelength side and detected by the frequency analysis unit 78A. The reflected light is 420.02184 nm.
In general, the relationship between the pitch d0 of the diffraction grating at room temperature and d1 after temperature rise, and the relationship between the wavelength λ0 of reflected light at room temperature and the wavelength λ1 of reflected light after temperature rise always satisfy the following relationship.
d1 / d0 = λ1 / λ0
Therefore, if the rate of change of the reflected light before and after the temperature rise is integrated with the known pitch d of the diffraction grating, it is possible to accurately estimate the amount of extension of the pitch d accompanying the temperature rise.

  As described above, in the present invention, the temperature can be measured without using any heat medium by using the diffraction gratings 68A and 68B formed on the mounting plate 42 itself. The temperature can be measured directly and accurately, and there is no risk of metal contamination.

  Moreover, the continuous temperature change of the mounting plate 42 can be measured, for example, continuous temperature measurement can be performed over a wide range of 0 ° C. to 1000 ° C. Further, if a ceramic material is used as the mounting plate 42, the ceramic material has a linear expansion coefficient that is about an order of magnitude higher than that of quartz glass, so that the resolution can be increased accordingly.

  As described above, the measurement light L1 is irradiated to the object to be measured, for example, the diffraction gratings 68A and 68B formed on the mounting plate 42 in this case to generate the diffraction light, and the diffraction light from the diffraction gratings 68A and 68B is generated. Based on this, the temperature of the object to be measured can be obtained. Therefore, by providing the diffraction gratings 68A and 68B on the object to be measured as described above, the temperature measurement accuracy can be greatly improved without causing metal contamination.

  In the above embodiment, the case where the diffraction grating 68 is provided on the lower surface (back surface) of the mounting plate 42 has been described as an example. However, the present invention is not limited to this. For example, as in the modification of the diffraction grating mounting structure shown in FIG. 6, the mounting plate 42 itself is set to a thickness of about 10 mm, for example, and a mounting hole 94 having an inner diameter of about 5 mm is formed from the side surface. The diffraction grating 68 may be directly formed on the bottom surface (side surface) of the mounting hole 94 and the optical waveguide 70 may be inserted into the mounting hole 94 and fixed.

In this case, not only can the same effects as the above-described embodiment be exhibited, it is difficult to be affected by stray light without modulating the measurement light, and the tip of the optical waveguide may be contaminated by the process gas. Since there is no, it has the advantage that it can prevent that translucency falls.
In the above embodiment, for example, the function of guiding the measurement light L1 to the diffraction grating 70 by one optical waveguide (optical fiber) 70A and the function of receiving the diffracted light from the diffraction grating 70 and guiding it to the frequency analysis unit 78A. However, the present invention is not limited to this, and two optical fibers may be provided. FIG. 7 is a schematic configuration diagram showing an embodiment of such a modification of the optical waveguide. The same components as those shown in FIG. 2 are denoted by the same reference numerals.

  That is, here, for example, two optical fibers are integrally joined, and one of the optical fibers is used as the first optical waveguide 70A-1 for guiding the measurement light L1 to the diffraction grating, and the other light is used. The fiber is used as the second optical waveguide 70A-2 for guiding the diffracted light L2 from the diffraction grating to the frequency analysis unit 78A.

  In this case, it is not necessary to provide the spectroscope 76A used in FIG. 2, and the apparatus cost can be reduced correspondingly. It is needless to say that the configuration shown in FIG. 7 can be similarly applied to the other optical waveguide 70B side.

  In this case, the first and second optical waveguides 70A-1 and 70A-2 are not integrated, and the second optical waveguide 70A-2 is positioned on the right side of the specular reflection direction 92 in FIG. It may be arranged in a region so as to receive any one of “−1st order” to “−3rd order” diffracted light.

<Another embodiment of mounting table structure>
In the heat treatment apparatus shown in FIG. 1 and FIG. 2, the mounting table structure 36 is configured such that the mounting table 42 including the mounting plate main body 40 and the mounting plate 42 are supported on the upper end of the support column 30. Although the structure 36 has been described as an example, the present invention is not limited thereto, and the present invention may be applied to a single wafer heat treatment apparatus using a heating lamp as a heating unit. FIG. 8 is a block diagram showing an example of a single wafer heat treatment apparatus using such a heating lamp. The same components as those shown in FIGS. 1 to 4 are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 8, this heat treatment apparatus 99 has a large-diameter cylindrical column 100 installed on the bottom 20 of the processing vessel 4 as the mounting table structure 36, and the inner diameter of the column 100 is The diameter is set to be slightly larger than the diameter of the thin mounting plate 42 that is the object to be measured. A plurality of, for example, three (only two in the illustrated example) L-shaped support rods 102 are provided extending from the upper end of the cylindrical support column 100 in the center direction. The tip portion of the support rod 102 supports the peripheral portion of the mounting plate 42 described above. Here, unlike the case of FIG.1 and FIG.2, the mounting base main body 40 is not provided.

  In addition, a clamp ring 106 connected to a push-up pin 54 that pushes up the wafer W through a rod 104 is provided above the periphery of the mounting plate 42, and this is moved up and down integrally with the push-up pin 54. Be able to. Then, by lowering the clamp ring 106, the peripheral portion of the wafer W is pressed against the mounting plate 42 side.

  A large-diameter opening 108 is formed in the bottom 20 of the processing container 4, and a transmission plate 112 is provided in the opening 108 via a seal member 110. A heating unit 44 for heating the wafer W is provided below the transmission plate 112. The heating means 44 here is configured by providing a plurality of heating lamps 116 on a reflecting plate 114 that is rotatable, and heat rays radiated from the heating lamps 116 are transmitted through the transmission plate 112 and made of an opaque material. The back surface of the mounting plate 42 is irradiated to heat it, whereby the wafer W mounted on the mounting plate 42 is indirectly heated.

  The above-described diffraction grating 68 is directly provided on the back surface (lower surface) of the mounting plate 42, and the optical waveguide 70 is provided with the tip portion facing the diffraction grating 68. Here, the optical waveguide 70 is preferably inserted into the protective tube 74. The optical waveguide 70 is provided with a spectrometer 76, a frequency analysis unit 78, a temperature analysis unit 80, and a temperature control unit 82.

  Even in the case of such a configuration, the same operational effects as those of the embodiment described above with reference to FIGS. In this case, in particular, the diffracted light from the heating lamp 116 can be easily separated by modulating the measurement light. When zone heating is performed on the mounting plate 42, the diffraction grating and the optical waveguide are provided for each zone. Furthermore, the modified embodiment described with reference to FIGS. 6 and 7 can be applied here.

In each of the above embodiments, a semiconductor wafer has been described as an example of the object to be processed. However, the present invention is not limited to this, and the present invention can be applied to a glass substrate, an LCD substrate, a ceramic substrate, and the like.
In addition, here, the object to be measured, which is the object of temperature measurement, has been described by taking the mounting plate 42 on which the object to be processed is mounted as an example. However, the present invention is not limited to this, and a diffraction grating can be directly formed on the surface. Any object can be used as the object to be measured, and the temperature can be accurately measured without contact.

It is a cross-sectional block diagram which shows the heat processing apparatus which has the mounting base structure using the temperature measuring apparatus which concerns on this invention. It is an enlarged view which shows a part of mounting base structure which provided the temperature measuring apparatus. It is a top view which shows an example of the diffraction grating provided in the lower surface of the mounting board. It is explanatory drawing explaining the state of the diffracted light by a diffraction grating. It is a figure which shows the state of diffracted light when making it inject | emit measurement light and incident diffracted light by the same optical waveguide. It is a figure which shows the modification of the attachment structure of a diffraction grating. It is a schematic block diagram which shows embodiment of a deformation | transformation of an optical waveguide. It is a block diagram which shows an example of the single-wafer | sheet-fed heat processing apparatus using a heating lamp.

Explanation of symbols

2 Heat treatment equipment 4 Processing vessel 6 Shower head (gas supply means)
26 Exhaust system 36 Mounting table structure 38 Mounting table 39 Support column 40 Mounting table body 42 Mounting plate (object to be measured)
44 heating means 46 resistance heater 49 heater power supply 50 temperature measuring device 68, 68A, 68B diffraction grating 70, 70A, 70B, 70A-1, 70A-2 optical waveguide 74, 74A, 74B protective tube 75 light emitting part 76, 76A, 76B Spectrometer 78, 78A, 78B Frequency analysis unit 80, 80A, 80B Temperature analysis unit 82 Temperature control unit 84 Device control unit 86 Storage medium 99 Heat treatment device 100 Support column 102 Support rod 116 Heating lamp d Interval (lattice constant)
L1 Measurement light L2 Diffracted light W Semiconductor wafer (object to be processed)

Claims (17)

In a temperature measuring device that measures the temperature of a measured object,
A diffraction grating formed on the object to be measured;
A light emitting section for generating measurement light for temperature measurement;
A first optical waveguide for guiding the measurement light to the diffraction grating;
A second optical waveguide for guiding diffracted light from the diffraction grating;
A frequency analyzer that receives the diffracted light guided by the second optical waveguide and analyzes the frequency;
A temperature analysis unit for determining the temperature of the measurement object based on the output of the frequency analysis unit;
A temperature measuring device comprising: The temperature measuring apparatus according to claim 1, wherein the diffraction grating is directly formed on a surface of the object to be measured. The temperature measuring apparatus according to claim 1, wherein the diffraction grating is formed on an inner surface of a hole formed in the measurement object. 4. The temperature according to claim 1, wherein the first optical waveguide and the second optical waveguide are fixed at a fixed angle with respect to the diffraction grating. 5. measuring device. The temperature measuring device according to any one of claims 1 to 4, wherein the first optical waveguide and the second optical waveguide are integrally joined. The first optical waveguide and the second optical waveguide are shared by a single optical waveguide, and a spectroscope for splitting the diffracted light is provided in the middle of the combined optical waveguide. The temperature measuring device according to any one of claims 1 to 4, wherein The temperature measuring apparatus according to any one of claims 1 to 6, wherein the first optical waveguide and the second optical waveguide are accommodated in a protective tube. The temperature measuring device according to claim 1, wherein the measurement light is modulated. The temperature measuring device according to claim 1, wherein the measurement light is broadband light having a constant frequency width. The temperature measuring apparatus according to claim 9, wherein the broadband light is white light. In a mounting table structure having a mounting plate made of an opaque material for mounting the object to be processed in order to perform a predetermined heat treatment on the object to be processed in a processing container made evacuable,
A mounting table structure comprising the temperature measuring device according to any one of claims 1 to 10 and a diffraction grating of the temperature measuring device provided on the mounting plate. The mounting table structure according to claim 11, wherein the diffraction grating is formed on a back surface of the mounting plate. The temperature measuring device according to claim 11, wherein the diffraction grating is formed on an inner surface of a hole formed in the mounting plate. The mounting table structure according to any one of claims 11 to 13, wherein the mounting plate is made of opaque quartz glass or an opaque ceramic material. The mounting table structure according to claim 11, wherein the mounting plate is provided on a mounting table main body supported by a support column. 15. The mounting plate according to claim 11, wherein the mounting plate is supported by a plurality of support rods extending from an upper end portion of a cylindrical column having an inner diameter larger than that of the mounting plate. The mounting table structure according to any one of claims. In a heat treatment apparatus for performing a predetermined heat treatment on a workpiece,
A processing vessel that can be evacuated;
Gas supply means for supplying a predetermined gas into the processing container;
The mounting table structure according to any one of claims 11 to 16,
Heating means for heating the object mounted on the mounting table structure;
A temperature control unit for controlling the heating means based on the measured value of the temperature measuring device provided in the mounting table structure;
A heat treatment apparatus comprising:

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