JP2013257189A - Thermometric apparatus and processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermometric apparatus that can accurately figure out with a relatively simple structure the temperature of a processing object even in low temperature range.SOLUTION: A thermometric apparatus 54 that measures the temperature of a processing object W having a prescribed thickness comprises light emitting means 56 that irradiates the surface of the processing object with an S-polarized reference light in an oblique direction so that the light is reflected between a front face Wa and a rear face Wb within the processing object a plurality of times; light receiving means 58 that is positioned on the front face side of the processing object and receives a plurality of beams I, Iand Iof a reflected light H from the processing object; and temperature figuring-out means 60 that figures out the temperature of the processing object on the basis of the detected values of the plurality of beams obtained by the light receiving means. In this way, the temperature of the processing object is enabled to be accurately figured out with a relatively simple structure even in a low temperature range.

Description

  The present invention relates to a temperature measuring device that measures and determines the temperature of an object to be processed, and a processing device using the same.

  In general, in order to manufacture a semiconductor integrated circuit, various processes such as a film formation process, an oxidation diffusion process, a modification process, an etching process, and an annealing process are repeatedly performed on a semiconductor wafer such as a silicon substrate. It is very important to accurately obtain and control the temperature of the semiconductor wafer being processed in such various processes in order to maintain high element characteristics and quality. In order to measure the temperature of the semiconductor wafer being processed, it is known to use a non-contact type radiation thermometer in order to prevent the wafer itself from being contaminated with metal (for example, Patent Document 1). The radiation thermometer can only be used in a relatively high temperature range of, for example, 200 ° C. or higher, and it has been difficult to measure the temperature in a low temperature range lower than this temperature.

  On the other hand, as a non-contact type temperature measurement method, a method of measuring the wafer temperature by utilizing the temperature dependence of the transmitted light to the semiconductor wafer (for example, Patent Document 2), p-polarized light is applied to the surface of the semiconductor wafer. And the substrate emissivity obtained from the amount of reflected light from the first surface of the semiconductor wafer and the amount of reflected light from the second surface, and the like. A method of measuring the wafer temperature using the substrate transmittance or the like (for example, Patent Document 4) is known.

JP 2008-235858 A Special table 2010-515521 gazette JP 2007-040981 A Special table 2009-500851 gazette

  However, in the case of the above-mentioned Patent Document 2, if the reflectance on the wafer surface changes during the process, the amount of transmitted light also changes. However, no consideration is given to the change in the reflectance on the wafer surface in this case. Therefore, it is conceivable that the accuracy of the temperature measurement value decreases.

  In the case of Patent Document 3, since the wafer temperature is obtained only from the reflected light on the wafer surface, no consideration is given to the change in the light absorption rate of the wafer. It is conceivable that the accuracy of the is reduced.

  Furthermore, in the case of Patent Document 4, a device for obtaining the amount of reflected light from the first surface of the wafer and a number of radiation measuring devices for sensing the amount of radiation emitted from the substrate during heating must be provided. There is a problem that the device itself is considerably complicated.

  The present invention has been devised to pay attention to the above problems and to effectively solve them. The present invention is a temperature measuring apparatus and a processing apparatus capable of accurately obtaining the temperature of an object to be processed even in a low temperature range with a relatively simple structure.

  The invention according to claim 1 is the temperature measuring device for measuring the temperature of the object to be processed having a predetermined thickness, in order to repeat the reflection a plurality of times between the front surface and the back surface in the object to be processed. A light emitting means for irradiating the surface of the body with reference light made s-polarized from an oblique direction, and light reception for receiving a plurality of beams of reflected light from the object to be processed, which is positioned on the surface side of the object to be processed And a temperature calculation means for obtaining the temperature of the object to be processed based on the detected values of the plurality of beams obtained by the light receiving means.

  As a result, the temperature of the object to be processed can be accurately obtained even in a low temperature range with a relatively simple structure.

  According to a seventh aspect of the present invention, in a processing apparatus for performing a predetermined process on a target object having a predetermined thickness, a processing container that houses the target object, and the target object in the processing container. A supporting means for supporting, a heating means for heating the object to be processed, the temperature measuring apparatus according to any one of claims 1 to 6, and controlling the heating means based on a measurement value of the temperature measuring apparatus. Thus, a processing apparatus comprising temperature adjusting means for adjusting the temperature of the object to be processed and apparatus control means for controlling the entire processing apparatus.

According to the temperature measuring apparatus and the processing apparatus according to the present invention, the following excellent operational effects can be exhibited.
In a temperature measuring device that measures the temperature of a target object having a predetermined thickness, the temperature of the target object can be accurately obtained even in a low temperature range with a relatively simple structure.

It is sectional drawing which shows schematic structure of an example of the temperature measuring apparatus which concerns on this invention, and a processing apparatus using the same. It is the elements on larger scale which show the relationship between the light emission means and light reception means of the temperature measurement apparatus which concerns on this invention. It is a graph which shows an example of the relationship between the light absorption rate and the temperature of a silicon wafer. It is a graph which shows the relationship between the wavelength of reference light, and the light absorption rate of a silicon wafer.

  Hereinafter, an embodiment of a temperature measuring apparatus and a processing apparatus according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing a schematic configuration of an example of a temperature measuring apparatus according to the present invention and a processing apparatus using the temperature measuring apparatus, and FIG. FIG. In FIG. 2, the description of the light transmission plate is omitted. Here, a case where a semiconductor wafer made of, for example, a silicon substrate is annealed as an object to be processed will be described as an example.

  As shown in FIG. 1, the annealing treatment apparatus 2 has a treatment container 4 having a hollow interior made of aluminum or an aluminum alloy. The processing container 4 includes a cylindrical side wall 4A, a ceiling plate 4B bonded to the upper end of the side wall, and a bottom plate 4C bonded to the bottom of the side wall. On the side wall 4A, a loading / unloading port 6 having a size capable of loading / unloading a semiconductor wafer W as an object to be processed is formed, and a gate valve 8 that can be opened and closed is attached to the loading / unloading port 6.

  A support means 10 for supporting the wafer W is provided in the processing container 4. The support means 10 has a plurality of, for example, three support pins 12 (only two are shown in FIG. 1) and a lifting arm 14 connected to the lower ends of these support pins 12. Each elevating arm 14 can be moved up and down by an actuator (not shown). Thereby, the whole can be moved up and down while the wafer W is supported on the upper end portion of the support pins 12.

Gas supply means 16 is formed in a part of the periphery of the ceiling plate 4B. The gas supply means 16 has a gas inlet 18 formed in the ceiling plate 4B and a gas pipe 20 connected to the gas inlet 18, and the necessary processing gas is shown in the processing container 4 as shown in the figure. It can be introduced while controlling the flow rate with a flow controller that does not. Here, an inert gas such as N ₂ or a rare gas such as Ar or He can be used as the processing gas.

  A gas exhaust port 22 is formed in a part of the periphery of the bottom plate 4C, and the gas exhaust port 22 is provided with an exhaust means 24 for exhausting the atmosphere in the processing container 4. The exhaust means 24 has a gas exhaust pipe 26 connected to the gas exhaust port 22, and a pressure regulating valve 28 and an exhaust pump 30 are sequentially provided in the gas exhaust pipe 26.

  A large-diameter opening is formed in the center of the ceiling plate 4B, and a heating means 32 on the surface side is provided in the opening to heat the surface (upper surface) of the wafer W. In addition, a large-diameter opening is formed at the center of the bottom plate 4C, and a heating means 34 on the back side is provided in the opening so as to face the heating means 32 on the front side. The back surface (lower surface) is heated. Here, the surface of the wafer W refers to the surface on which various processes such as film formation and etching are performed. Further, when the heating amount of the heating means 32 on the front surface side is sufficiently large, the heating means 34 on the back surface side can be omitted without being provided.

  Next, the heating device will be described. Here, the heating means 32 on the front surface side and the heating means 34 on the back surface side are configured in exactly the same manner except that they are upside down, so here the heating means 32 on the front surface side is taken as an example. For the sake of explanation, the heating means 34 on the back side is denoted by the same reference numerals, and the description thereof is omitted. The heating means 32 on the surface side has an element mounting head 36 that is fitted into the opening of the ceiling plate 4B with a slight gap.

  The element mounting head 36 is formed of a material having high thermal conductivity such as copper, aluminum, or an aluminum alloy. This element mounting head 36 is supported by a circular ring-shaped mounting flange 36A formed on the upper side of the element mounting head 36 with a thermal insulator 38 made of polyetherimide or the like interposed between the element mounting head 36 and the ceiling plate 4B.

  In addition, a sealing material 40 made of an O-ring or the like is interposed on the upper and lower sides of the thermal insulator 38 so as to maintain the airtightness of this portion. An element mounting recess 42 having a diameter slightly larger than the diameter of the wafer W is formed on the lower surface of the element mounting head 36, and at least a portion of the wafer W is formed on a flat portion of the element mounting recess 42. A plurality of LED modules 44 are provided over an area large enough to cover the entire surface. In addition, a light transmission plate 46 made of, for example, a quartz plate is attached to the opening portion of the element attachment recess 42. The LED module 44 emits light toward the wafer W.

  A cooling mechanism 48 is provided above the LED module 44, that is, on the side opposite to the wafer W. The cooling mechanism 48 has a refrigerant passage 50 having a rectangular cross section provided in the element mounting head 36. The cooling mechanism 48 is cooled by removing the heat generated from the LED module 44 by flowing the refrigerant through the refrigerant passage 50. It has come to be able to do. As this refrigerant, water, Fluorinert, Galden (trade name) or the like can be used. Further, the refrigerant passage 50 is formed so as to be folded in a meandering manner, for example, over substantially the entire surface of the element mounting head 36, and cools it by taking heat from the LED module 44. .

  The LED modules 44 are, for example, in a regular hexagonal shape with one side of about 40 mm, and are arranged close to each other so that adjacent sides are substantially in contact with each other. A plurality of LED modules 44 are provided. For example, when the diameter of the wafer W is 300 mm, about 20 are provided. Each LED module 44 is configured by arranging a plurality of LED elements (not shown) vertically and horizontally on the surface thereof.

  In this case, the size of each LED element is about 0.5 mm × 0.5 mm, and about 1000 to 2000 LED elements are mounted on one LED module 44. The plurality of LED modules 44 are, for example, concentrically divided into a plurality of regions, and power control can be performed for each of the sections so that the wafer W can be heated and controlled concentrically for each zone. As described above, the heating means 34 on the back side is formed in the same manner as the heating means 32 on the front side as described above, and is configured so as to be attached to the bottom plate 4C side upside down. .

  The processing device 2 is provided with a temperature measuring device 54 according to the present invention for measuring the temperature of the semiconductor wafer W, and each heating means 32 based on the measured value obtained by the temperature measuring device 54. , 34 is provided for controlling the temperature.

  Specifically, as shown in FIGS. 1 and 2, the temperature measurement device 54 is configured so that the reflection of the wafer W is repeated a plurality of times between the front surface and the back surface of the semiconductor wafer W having a predetermined thickness. A light emitting means 56 for irradiating the surface with s-polarized reference light from an oblique direction; a light receiving means 58 for receiving a plurality of beams of reflected light from the wafer W located on the surface side of the wafer W; Temperature calculating means 60 for obtaining the temperature of the wafer W based on the detection values of the plurality of beams obtained by the light receiving means 58.

  Here, the light emitting means 56 is attached to the lower surface of the heating means 32 on the surface side. The light emitting means 56 includes a light emitting element 62 and a polarizing plate 64 (see FIG. 2), and passes the light output from the light emitting element 62 through the polarizing plate 64 and outputs only the s-polarized light as the reference light I. It has become. The reason why s-polarized light is used is that when the light component of s-polarized light is reflected on the surface of the wafer W, the light intensity can be sufficiently large regardless of the angle of the Brewster.

  As the light emitting element 62, an LED (Light Emitting Diode) element or an LD (Laser Diode) element that outputs laser light can be used. In this case, it is preferable to use an LD element that outputs reference light I having a uniform wavelength. As the reference light I, infrared light having a wavelength in the range of, for example, 1000 to 1300 nm is used.

  Similarly to the light emitting means 56, the light receiving means 58 is attached to the lower surface of the heating means 32 on the surface side, and receives a plurality of beams of the reflected light H reflected from the wafer W. Yes. In this case, the incident angle θ of the reference light I with respect to the surface Wa of the wafer W is in the range of 40 to 80 degrees, preferably in the range of 55 to 65 degrees. The light receiving means 58 includes a light receiving element 66 having a predetermined length so as to receive a plurality of beams reflected in a state of being arranged in parallel. As the light receiving element 66, a photodiode element, a CCD (Charge Coupled Device) element, or the like can be used.

When the reference light I enters the semiconductor wafer W having a predetermined thickness L from the front surface Wa from the oblique direction of the incident angle θ, the reference light I is gradually attenuated while being repeatedly reflected a plurality of times between the back surface Wb and the front surface Wa of the wafer W. Will go. When the reference light I is incident on the wafer W from the front surface Wa, a part is reflected as the reflected light H, and when the reference light is repeatedly reflected between the front surface Wa and the back surface Wb and reflected by the front surface Wa. In each case, a part of the reference light is transmitted to the outside of the surface Wa and exits as reflected light H. Similarly, when the reference light is repeatedly reflected between the front surface Wa and the back surface Wb and reflected by the back surface Wb, a part of the reference light is transmitted to the outside of the back surface Wb each time and transmitted light T ( T ₁ , T ₂ , T ₃ ...

  In this case, the light receiving element 66 detects a beam formed by reflecting a part of the reference light from the surface Wa when the reference light I enters the wafer W. Further, the light receiving element 66 also detects a plurality of beams formed by transmitting a part of the reference light to the outside of the surface Wa when the reference light repeatedly reflected in the wafer W is reflected by the surface Wa. It is like that.

Specifically, when the reference light I is incident on the wafer W, the beam I ₀ of the reflected light H that is reflected from the surface Wa and the reference light that has entered the wafer W are reflected once by the back surface Wb and then the surface Wa. The reflected light beam I ₁ that has been transmitted through and the reference light that has entered the wafer W are reflected twice by the back surface Wb, reflected once by the surface Wa, and then transmitted through the surface Wa. The light receiving element 66 receives the reflected light beam I ₂ .

Here, the reference light repeatedly reflected in the wafer W is reflected three times on the back surface Wb and twice on the front surface Wa, and then the reflected light beam I ₃ transmitted through the front surface Wa is reflected by the light receiving element 66. It does not receive light. Here, when the thickness L of the wafer W is 0.75 mm and the incident angle θ is 60 degrees, the distance between the beams I _{0 to} I ₃ is 0.38 mm. Therefore, the distance between beam I ₀ and beam I ₂ is 0.76 mm. In FIG. 2, the light intensities of the beams I _{0 to} I ₃ are shown together, and the light intensity decreases as the number of reflections increases. Therefore, although it depends on the sensitivity of the light receiving element 66, it reflects as much as possible. It is preferable to detect and use a beam with a small number of times.

The temperature calculation unit 60 is formed of, for example, a microprocessor, and the temperature calculation unit 60 includes a reference information storage unit 66 that stores reference information representing the relationship between the light absorption rate of the wafer W and the temperature. The temperature calculating means 60 calculates and obtains the temperature of the wafer W based on the detected values of the beams I _{0 to} I ₂ and the reference information.

The temperature calculating means 60 has a display unit 68 for displaying the calculated temperature value, and this temperature value is sent to the temperature adjusting means 52 for controlling the wafer temperature. The reference information stored in the reference information storage unit 66 indicates the relationship between the light absorption rate and the temperature as described above. Table More specifically, the function of the graph shown in the table and Figure 3 showing the relationship between the graph and the light absorption rate and the temperature showing an example of the relationship between the temperature of the light absorption rate and Shirikon'u Movement as shown in FIG. 3 The reference information is stored in the reference information storage unit 66.

  FIG. 3 shows a graph when the wavelength of the reference light is 1100 nm, 1150 nm, and 1200 nm. The horizontal axis indicates the optical absorptance of a silicon substrate having a thickness of 0.75 mm, and the vertical axis indicates the temperature of the wafer. ing. For example, when the wavelength is 1100 nm, the light absorptance changes from about 0.1 to 0.5, and the temperature at that time changes from room temperature (25 ° C.) to about 140 ° C. Further, when the wavelength is 1150 nm, the temperature changes from about 0.1 to 0.8, and the temperature at that time changes from room temperature (25 ° C.) to about 300 ° C. Furthermore, when the wavelength is 1200 nm, it changes from about 0.1 to 0.8, and the temperature at that time changes from room temperature (25 ° C.) to about 400 ° C. As is apparent from this graph, it can be seen that the wafer temperature increases almost linearly as the light absorption rate increases. Also, according to this graph, it can be seen that the optimum frequency may be used by changing the frequency used depending on the temperature range to be measured.

  As described above, the reason why the wafer temperature is required in accordance with the change in the light absorption rate is that, when the reference light incident on the wafer is constant at a certain wavelength, the light absorption rate of the wafer changes depending on the temperature. This is a phenomenon that uses this phenomenon. That is, FIG. 4 is a graph showing the relationship between the wavelength of the reference light and the light absorption rate of the silicon wafer. As shown in FIG. 4, for example, when the wavelength of the reference light is 1150 nm, if the wafer temperature is changed to 50 ° C., 200 ° C., or 400 ° C., the light absorptance of the wafer also changes accordingly. I understand. Using such characteristics, reference information as shown in FIG. 3 is obtained.

  Judging from FIG. 4, as the reference light I, light having a wavelength in the range of 1000 nm to 1300 nm is preferably used, and light in the range of 1050 nm to 1200 nm is preferably used. Incidentally, the reference information as shown in FIG. 3 naturally changes depending on the wavelength of the reference light to be used and the material, thickness, etc. of the semiconductor wafer W as the object to be processed, and corresponds to the above-mentioned wavelength, material, thickness, etc. Thus, a plurality of types of reference information may be stored and used selectively.

Here, an example of the calculation performed in the temperature calculation means 60 will be described. The reflectance of the front surface Wa of the wafer W is “Ra”, the reflectance of the back surface Wb is “Rb”, and the light absorption rate of a silicon substrate having a thickness of 0.75 mm is “A”. The light intensities of the beams I ₀ , I ₁ , and I ₂ of the reference light I and the reflected light H are “I”, “I ₀ ”, “I ₁ ”, and “I ₂ ”, respectively. Here, the front surface Wa is a surface on which various processes such as film formation and etching are performed on the wafer W, and the back surface Wb is the opposite surface.

  The reflectance Ra of the front surface Wa tends to change with the progress of processing, whereas the reflectance Rb of the rear surface Wb is relatively stable even when processing of the wafer W proceeds. The reflectance Rb of the back surface Wb is determined in advance by measurement. The wavelength of the s-polarized reference light I is known. The reflectance Rb and the wavelength of the reference light I are stored in advance in the reference information storage unit 66, the memory of the temperature calculation unit 52, or the like.

First, the relationship between I ₀ , I ₁ , and I ₂ is determined as follows.
I ₁ ² / (I ₀ · I ₂ ) = [(1-Ra) / Ra] ² (1)
The above equation 1 is modified as follows.
Ra = 1 / [1 + √ (I ₁ ² / (I ₀ · I ₂ ))] (2)

Here, each of I ₀ , I ₁ , and I ₂ is as follows.
I ₀ = Ra · I (3)
I ₁ = (1-A) ² Rb (1-Ra) ² · I (4)
I ₂ = (1-A) ⁴ Ra · Rb ² (1-Ra) ² · I (5)
From the above equations 4 and 5, the following equations are obtained.
I ₂ / I ₁ = (1-A) ² Ra · Rb (6)
When this equation 6 is modified, the light absorption rate A is as follows.
A = 1-√ [I ₂ / (I ₁ · Ra · Rb)] (7)

Here, by substituting “Ra” in Equation 2 into Equation 7 and entering “I ₀ ”, “I ₁ ”, and “I ₂ ” as measured values, the light absorption rate A is determined. By referring to the reference information as shown in FIG. 3 based on the value of the light absorption rate A, the wafer temperature at that time can be obtained. In this case, since the reflectance Ra of the surface Wa of the wafer W is taken into account as apparent from the above equation 7, even if the reflectance Ra of the surface Wa of the wafer W varies during the process, the wafer temperature is always accurately adjusted. It becomes possible to ask for.

  Now, referring back to FIG. 1, various operations such as control of the entire operation of the processing apparatus 2 formed in this way, such as process pressure, gas flow rate, on / off of the heating means 32 on the front side and the heating means 34 on the back side, etc. The control is performed by the apparatus control means 70 formed of, for example, a computer, and a computer-readable program necessary for this control is stored in the storage medium 72. Here, the temperature adjusting means 52 operates under the control of the apparatus control means 70 to control the process temperature. As the storage medium 72, for example, a flexible disk, a CD (Compact Disc), a CD-ROM, a hard disk, a flash memory, a DVD, or the like is used.

  Next, the annealing process performed using the processing apparatus 2 configured as described above will be described. First, a semiconductor wafer W made of, for example, a silicon substrate is previously brought into a reduced-pressure atmosphere from a load-lock chamber or transfer chamber chamber (not shown) that has been previously in a reduced-pressure atmosphere by a transfer mechanism (not shown) through an opened gate valve 8. Into the processing container 4.

  The surface Wa of the wafer W is subjected to various thin film forming processes and pattern etching processes. The loaded wafer W is transferred onto the support pins 12 provided on the elevating arm 14 by driving the elevating arm 14 up and down. After the transfer mechanism is retracted, the gate valve 8 is moved. Is closed to close the inside of the processing container 4.

Next, while controlling the flow rate from the gas pipe 20 of the gas supply means 16, a processing gas, for example, N ₂ gas or Ar gas is flowed here, and the inside of the processing container 4 is maintained at a predetermined pressure. At the same time, the heating means 32 on the front surface side provided on the ceiling plate 4B and the heating means 34 on the back surface side provided on the bottom plate 4C are both turned on, and the LED elements of the LED modules 44 of the heating means 32 on the front surface side are turned on. In addition, the LED elements of the LED modules 44 of the heating means 34 on the back surface side are both turned on and irradiated with heating light, and the wafer W is heated from both the upper and lower surfaces and annealed. In this case, the process pressure is, for example, about 100 to 10000 Pa, the process temperature (wafer temperature) is, for example, about 800 to 1100 ° C., and the lighting time of each LED element is, for example, about 1 to 10 seconds.

  As a result, the front and back surfaces of the wafer W are irradiated with the heating light and rapidly heated to a predetermined temperature. At this time, the temperature of the semiconductor wafer W is accurately measured by the temperature measuring device 54 according to the present invention, and the temperature adjusting means 52 controls the heating means 32 and 34 based on the measured value. Therefore, the temperature of the semiconductor wafer W can be adjusted with high accuracy.

Specifically, electric power is supplied to the light emitting means 56 of the temperature measuring device 54 provided in the heating means 32 on the surface side, and laser light is emitted from the light emitting element 62 of the light emitting means 56, and this laser light is converted into a polarizing plate. By passing through 64, it becomes s-polarized reference light I and enters the surface Wa of the wafer W from an oblique direction at an incident angle θ. A part of this reference light I is reflected from the surface Wa when entering, and proceeds as a beam I ₀ of reflected light H.

On the other hand, the reference light that is incident while being refracted into the wafer W advances while being repeatedly reflected between the back surface Wb and the front surface Wa of the wafer W and gradually attenuates. Here, each time the reference light traveling while being repeatedly reflected between the back surface Wb and the front surface Wa of the wafer W is reflected by the front surface Wa, a part of the reference light is refracted through the front surface Wa and reflected to the outside. It proceeds as light H, and beams I ₀ , I ₁ , I ₂ , I ₃ ... Of reflected light H are formed. Then, the light receiving element 66 made of, for example, a CCD of the light receiving means 58 receives the beam I ₀ and a plurality of the beams I ₁ , I ₂ , I ₃ ..., Here the beams I ₁ and I _2. Thus, the light intensities of the beams I ₀ , I ₁ , and I ₂ are detected, respectively. The detected values of the beams I ₀ , I ₁ and I ₂ are sent to the temperature calculation means 60.

Here, the reflectance Rb on the back surface Wb side of the wafer W is measured in advance as described above, and the measured value is stored in the memory of the temperature calculation means 60, the reference information storage unit 66, or the like. The frequency of the reference light I is determined in advance, and corresponding reference information indicating the relationship between the light absorption rate and the wafer temperature as shown in FIG. 3 is stored in the reference information storage unit 66 in advance. The temperature calculation means 60 obtains the reflectance Ra of the surface Wa of the wafer W from the light intensities “I ₀ ”, “I ₁ ”, “I ₂ ” and the above equation 2. Further, the light absorptance A of the wafer W is obtained from the reflectance Ra, the reflectance Rb measured in advance, the light intensity “I ₁ ”, “I ₂ ”, and Equation 7 above.

  Then, the temperature of the silicon wafer is obtained based on this light absorption rate A and reference information (graph) as shown in FIG. For example, according to FIG. 3, when the wavelength of the reference light is 1150 nm and the light absorption rate A is “a1”, the wafer temperature is substantially “t1 ° C.”. When the measured value of the wafer temperature is obtained in this way, this measured value is output to the temperature adjusting means 52, and the temperature adjusting means 52 is heated based on this measured value as described above. , 34 are feedback-controlled to adjust the temperature of the wafer W to maintain a predetermined process temperature.

  Thus, the temperature of the wafer W can be obtained with high accuracy even in the low temperature range of about 25 ° C. to 600 ° C. by the temperature measuring device 54. In this case, even if the reflectance Ra of the surface Wa of the wafer W fluctuates during the process, the reflectance Ra is incorporated into the calculation formula of the light absorption rate A as shown in Expression 7 and is taken into consideration. Therefore, the temperature of the wafer W can be accurately obtained without adversely affecting the accuracy of the measured value of the wafer temperature. Here, as described above, the reference information storage unit 66 stores a plurality of types of reference information corresponding to the wavelength of the reference light I, the material and thickness of the wafer W, and the wavelength, material and thickness. By specifying the reference information, the reference information may be selectively used.

  As described above, according to the present invention, the temperature measuring device 54 for measuring the temperature of the workpiece W having a predetermined thickness can accurately obtain the temperature of the workpiece with a relatively simple structure even in a low temperature range. Can do.

In the above embodiment, a plurality of beams I ₁ and I ₂ are used in addition to the reflected light beam I ₀ in order to calculate the temperature of the wafer. However, the present invention is not limited to these beams I ₁ and I _2. In addition to I ₀ , other combinations such as beams I ₁ and I ₃ or I ₂ and I ₃ may be used. Although the case where the wafer W is processed in the reduced pressure atmosphere in the processing container 4 has been described as an example here, the present invention is not limited to this, and the present invention can also be applied to the case where the wafer W is processed in an atmospheric pressure atmosphere. Of course.

  In the above embodiment, the heating means 32 and 34 are provided on both the ceiling side and the bottom side of the processing container 4 to heat the wafer W from both sides. However, the present invention is not limited to this. The heating means may be provided to heat the wafer W from one side. In this case, if the heating means 34 on the back surface side is not provided, a disk-shaped cooling table provided with a cooling mechanism is provided here, and the annealed wafer W is placed on the cooling table and cooled. It may be.

  Although the case where an LED element or an LD element is used as the heating means 32 and 34 has been described as an example here, the present invention is not limited to this, and a heating means including a heating lamp may be used. Furthermore, in addition to or in place of the heating means of the LED element, LD element and heating lamp, a heating means comprising a plasma generating mechanism for generating plasma may be provided. The wafer temperature can be adjusted by controlling the power applied to the generating mechanism.

  In the above embodiment, the case where the annealing process is performed on the wafer W has been described as an example. can do.

  Although the semiconductor wafer is described as an example of the object to be processed here, the semiconductor wafer includes a silicon substrate and a compound semiconductor substrate such as GaAs, SiC, GaN, and the like, and is not limited to these substrates. The present invention can also be applied to glass substrates, ceramic substrates, and the like used in display devices.

DESCRIPTION OF SYMBOLS 2 Processing apparatus 4 Processing container 4A Side wall 4B Ceiling board 4C Bottom board 10 Support means 16 Gas supply means 24 Exhaust means 32 Heating means on the surface side 34 Heating means on the back side 44 LED module 52 Temperature adjusting means 54 Temperature measuring device 56 Light emitting means 58 Light receiving means 60 Temperature calculating means 62 Light emitting element 64 Polarizing plate 66 Reference information storage section 70 Device control means I Reference beam I ₀ , I ₁ , I ₂ , I ₃ Reflected light beam H Reflected light W Semiconductor wafer (object to be processed)
Wa Front Wb Back

Claims (7)

In a temperature measuring device for measuring the temperature of an object to be processed having a predetermined thickness,
A light emitting means for irradiating the surface of the object to be treated with s-polarized reference light from an oblique direction in order to repeat reflection between the surface and the back surface a plurality of times in the object to be treated;
A light receiving means that is positioned on the surface side of the object to be processed and receives a plurality of beams of reflected light from the object to be processed;
Temperature calculating means for determining the temperature of the object to be processed based on the detection values of the plurality of beams obtained by the light receiving means;
A temperature measuring device comprising: The plurality of beams includes a beam formed by reflecting a part of the reference light from the surface when the reference light is incident on the object to be processed. Temperature measuring device. The plurality of beams include a plurality of beams formed by transmitting a part of the reference light to the outside of the surface when the reference light that repeats reflection in the object to be processed is reflected on the surface. The temperature measuring device according to claim 2, wherein The said temperature calculation means has a reference information memory | storage part which memorize | stores the reference information showing the relationship between the light absorption rate of the said to-be-processed object, and temperature, The Claim 1 thru | or 3 characterized by the above-mentioned. Temperature measuring device. The temperature measurement apparatus according to claim 1, wherein the wavelength of the reference light is in a range of 1000 to 1300 nm. The temperature measurement apparatus according to claim 1, wherein an incident angle of the reference light is in a range of 40 to 80 degrees. In a processing apparatus for performing a predetermined process on an object to be processed having a predetermined thickness,
A processing container for containing the object to be processed;
A support means for supporting the object to be processed in the processing container;
Heating means for heating the object to be processed;
The temperature measuring device according to any one of claims 1 to 6,
Temperature adjusting means for adjusting the temperature of the object to be processed by controlling the heating means based on the measurement value of the temperature measuring device;
Device control means for controlling the entire processing device;
A processing apparatus comprising:

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