JP2015184234A - Temperature measurement device and temperature measurement method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature measurement device and a temperature measurement method capable of accurately measuring the temperature of a measurement object having permeability with respect to radiation energy in a specific wavelength band by using a radiation thermometer.SOLUTION: A control part 10 includes: a relational expression calculation part 11 for calculating a relational expression indicating a relation between an error between the temperature of a silicon wafer measured by a radiation thermometer 3 and the actual temperature of the silicon wafer and the temperature of a reflector; a relational expression storage part 12 for storing the relational expression; and a temperature correction part 13 for correcting the temperature of the silicon wafer measured by the radiation thermometer 3 by using the relational expression.

Description

  The present invention relates to a temperature measuring device and a temperature measuring method for measuring the temperature of a measurement object having transparency to radiant energy in a specific wavelength range in a non-contact manner.

  Glass substrate for organic EL display device, glass substrate for liquid crystal display device, panel substrate for solar cell, glass substrate for plasma display, glass substrate for photomask, substrate for optical disk, semiconductor wafer, etc. When measuring, the temperature is generally measured without contact. This is because the temperature is often measured while the substrate is transported.

  In addition, when measuring the temperature of a very thin substrate, the substrate may be broken if the temperature of the substrate is measured with a contact-type thermometer, and further, the temperature of the substrate on which the film is formed is measured. In some cases, if the temperature of the substrate is measured with a contact-type thermometer, the film formation state may be adversely affected. In such a case, the temperature of the substrate is measured in a non-contact manner.

  In order to measure the temperature of the substrate in a non-contact manner, a radiation thermometer that measures the temperature of the substrate by detecting the radiation energy from the substrate is used. A temperature measuring device using a radiation thermometer and a thermocouple has also been proposed (see Patent Document 1 and Patent Document 2).

JP 2008-233302 A JP 2009-302177 A

  An industrial machine such as a substrate processing apparatus is usually made up of many parts made of metal or the like, and the temperature of an object to be measured such as a substrate is measured. Here, for example, when a measurement object that transmits radiation energy in a specific wavelength region including infrared rays used for temperature measurement, such as a silicon wafer, is measured with a radiation thermometer, the radiation thermometer is Silicon is affected not only by the radiant energy radiated from the silicon wafer, but also by the radiant energy from the non-transparent material such as metal behind the silicon wafer, which is in a vertically superposed relationship with the silicon wafer. There arises a problem that the temperature of the wafer cannot be measured accurately.

  In order to cope with such problems, the temperature of the silicon wafer is measured not from the direction orthogonal to the surface of the silicon wafer, but from an inclined direction, so that the silicon wafer is separated from the silicon wafer in the vertical direction. It is also conceivable to reduce the influence of radiant energy from non-transparent materials such as metals. However, when such a configuration is adopted, the radiation thermometer also measures the radiation energy from other objects reflected on the surface of the silicon wafer, and similarly accurately measures the temperature of the silicon wafer. The problem of not being possible arises.

  Such a problem is not limited to silicon wafers, and is a problem that occurs with respect to all measurement objects that are transparent to radiant energy in a specific wavelength range.

  The present invention has been made to solve the above problems, and it is possible to accurately measure the temperature of a measurement object that is transparent to radiant energy in a specific wavelength range by using a radiation thermometer. An object is to provide a temperature measuring apparatus and a temperature measuring method.

  According to the first aspect of the present invention, the temperature of the measurement object having transparency to the radiant energy in the specific wavelength region, the vertical direction of the measurement object and the member having low transparency to the radiant energy in the specific wavelength region Temperature measured in a direction perpendicular to the surface of the measurement object by a radiation thermometer disposed on the opposite side of the member with respect to the measurement object in a state of being separated and at least partially overlapped A temperature sensor that measures the temperature of the member; an error between a temperature of the measurement object measured by the radiation thermometer and an actual temperature of the measurement object; and a temperature of the member A relational expression storage unit that stores a relational expression indicating a relation, a relational expression stored in the relational expression storage unit, and a temperature measured by the radiation thermometer using the temperature of the member measured by the temperature sensor Characterized in that it comprises a temperature compensation unit for correcting the temperature of the measurement object.

  The invention according to claim 2 is the invention according to claim 1, further comprising a transport mechanism for transporting the measurement object, wherein the radiation thermometer is transported by the transport mechanism. The temperature of the measurement object is measured.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the temperature sensor is a thermocouple that contacts the member and measures the temperature of the member.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the measurement object is a silicon wafer.

  According to a fifth aspect of the present invention, the temperature of the measurement object having transparency with respect to the radiant energy in the specific wavelength range, the vertical direction of the measurement object with respect to the member having low transparency with respect to the radiant energy in the specific wavelength range, and Temperature measured in a direction perpendicular to the surface of the measurement object by a radiation thermometer disposed on the opposite side of the member with respect to the measurement object in a state of being separated and at least partially overlapped A measurement method, wherein the temperature of the member is changed, and a first temperature that is an equivalent temperature of the measurement object measured by the radiation thermometer and the measurement object measured by a first temperature sensor A temperature measuring step of measuring a second temperature which is a temperature of an equivalent of the object and a third temperature which is a temperature of the member measured by a second temperature sensor; 1 and 2 A relational expression calculating step for calculating a function indicating a relational expression indicating a relation between the error between the first temperature and the second temperature and the third temperature from a third temperature; and the measurement object The temperature measured by the radiation thermometer is measured by the radiation thermometer using the function calculated in the relational expression calculation step and the temperature of the member measured by the second temperature sensor. And a temperature correction step of correcting the temperature of the measurement object.

  According to the invention described in claim 1 and claim 5, even when the temperature of the measurement object having transparency to the radiant energy in the specific wavelength range is measured using a radiation thermometer, the measurement object It is possible to accurately measure the temperature of the measurement object by correcting the influence of the radiant energy from the low-permeability member that is at least partially overlapped with the object in the vertical direction.

  According to the second aspect of the present invention, it is possible to accurately measure the temperature of the object to be measured during conveyance that cannot be contacted.

  According to the third aspect of the present invention, it is possible to accurately measure the temperature of the low-permeability member with the thermocouple in contact with the low-permeability member.

  According to the fourth aspect of the present invention, it is possible to accurately measure the temperature of a silicon wafer that is highly permeable to radiant energy of a specific wavelength.

It is a schematic diagram of the temperature measuring device concerning this invention. It is a block diagram which shows the main control systems of the temperature measuring device which concerns on this invention. It is a flowchart which shows a preparation process. 4 is a graph showing an error between the temperature of the reflector 2, the temperature of the silicon wafer 1 measured by the radiation thermometer 3, and the actual temperature of the silicon wafer 1 measured by the thermocouple 5. It is a flowchart which shows a temperature measurement process. It is a table | surface for demonstrating the error before and behind correction | amendment at the time of applying this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of a temperature measuring device according to the present invention.

  In this temperature measuring device, a silicon wafer 1 for manufacturing a solar cell panel substrate as an object to be measured is transported in the horizontal direction on an upper portion of a stainless steel reflector 2 as a non-transmissive member by a transport device (not shown). However, the temperature of the silicon wafer 1 is measured by the radiation thermometer 3. As the radiation thermometer 3, a thermography, a pyrometer or the like can be used.

  In this embodiment, the silicon wafer 1 that is transported in the horizontal direction above the reflector 2 in a part of the manufacturing process of the solar cell in which the silicon wafer 1 for a solar cell panel substrate is processed in a temperature-controlled state. The temperature is measured. However, the present invention is not limited to such a form, and the temperature of the measurement object that is transparent to the radiant energy in the specific wavelength range is set to a temperature that is low in permeability to the radiant energy in the specific wavelength range. The present invention can be similarly applied to other configurations in which measurement is performed in a state of being superimposed on the transmission member.

  The radiation thermometer 3 measures the temperature of the silicon wafer 1 in a non-contact manner by measuring infrared rays as radiation in a specific wavelength range emitted from the silicon wafer 1. As will be described later, when the temperature of the silicon wafer 1 is measured by the radiation thermometer 3, the temperature of the reflector 2 is measured by the thermocouple 4 which is a contact-type thermometer. In addition, as this thermocouple 4 and the thermocouple 5 mentioned later, a sheath thermocouple, a resistance temperature detector, a thermistor, etc. can be used.

  In the case where the temperature of the silicon wafer 1 is measured by the temperature measuring device having such a configuration, the temperature of the silicon wafer 1 is measured by the radiation thermometer 3 from a direction orthogonal to the surface of the silicon wafer 1. Thus, the radiation thermometer 3 also measures the radiation energy from other objects reflected by the surface of the silicon wafer 1 as in the case of measuring the temperature of the silicon wafer 1 from a direction inclined with respect to the surface of the silicon wafer 1. Therefore, it is possible to measure only the radiant energy from the silicon wafer 1.

  On the other hand, when the temperature of the silicon wafer 1 is measured by the temperature measuring device having such a configuration, the silicon wafer 1 is transmissive to infrared rays, so that not only the infrared rays from the silicon wafer 1 but also silicon. Since the infrared rays from the reflector 2 that have passed through the wafer 1 also reach the radiation thermometer 3, there arises a problem that the temperature of the silicon wafer 1 cannot be measured accurately. For this reason, in the temperature measuring apparatus according to the present invention, a relational expression showing the relationship between the error between the temperature of the silicon wafer 1 measured by the radiation thermometer 3 and the actual temperature of the silicon wafer 1 and the temperature of the reflector 2 is obtained. Based on this, a configuration for correcting the temperature of the silicon wafer 1 measured by the radiation thermometer 3 is adopted.

  FIG. 2 is a block diagram showing a main control system of the temperature measuring apparatus according to the present invention.

  A temperature measuring apparatus according to the present invention includes a ROM that stores an operation program necessary for controlling the apparatus, a RAM that temporarily stores data and the like during control, and a CPU that executes logical operations, and controls the entire apparatus. A control unit 10 is provided. The control unit 10 is connected to the radiation thermometer 3 and the thermocouple 4 described above. Further, the control unit 10 includes a thermocouple 5 for measuring the temperature of the silicon wafer 1 by a contact method and a heating mechanism 6 for changing the temperature of the reflector 2 in a preparation step for obtaining a relational expression described later. Prepare. The thermocouple 5 corresponds to the first temperature sensor according to the present invention, and the thermocouple 4 corresponds to the second temperature sensor according to the present invention. Here, since the thermocouple 5 and the heating mechanism 6 described above do not need to be connected to the control unit 10 after the later-described relational expression calculation step is completed, the thermocouple 5 and the heating mechanism 6 are connected to the control unit. You may make it remove from 10.

  Further, the control unit 10 calculates a relational expression for calculating a relational expression indicating a relation between an error between the temperature of the silicon wafer 1 measured by the radiation thermometer 3 and the actual temperature of the silicon wafer 1 and the temperature of the reflector 2. Unit 11, a relational expression storage unit 12 that stores the relational expression, and a temperature correction unit 13 that corrects the temperature of the silicon wafer 1 measured by the radiation thermometer 3 using the relational expression.

  Next, the temperature measuring operation by the temperature measuring device according to the present invention will be described. In order to measure the temperature of the silicon wafer 1 by the temperature measuring device according to the present invention, in the preparation step, an error between the temperature of the silicon wafer 1 measured by the radiation thermometer 3 and the actual temperature of the silicon wafer 1, and a reflector The relational expression showing the relation with the temperature of 2 is calculated and stored. FIG. 3 is a flowchart showing this preparation process.

  In the preparation process, first, the reflector 2 is heated by the heating mechanism 6 shown in FIG. 2 (step S11). A silicon wafer that is equivalent to the silicon wafer 1 that is the measurement object is disposed at a position facing the radiation thermometer 3, and is equivalent to the silicon wafer 1 that is the measurement object measured by the radiation thermometer 3. The temperature of the silicon wafer is measured as the first temperature. Further, the temperature of the silicon wafer that is equivalent to the silicon wafer 1 that is the measurement object is measured by the thermocouple 5 as the second temperature. Further, the temperature of the reflector 2 is measured as the third temperature by the thermocouple 4 (step S12). The “equivalent of the silicon wafer 1 as the measurement object” may be any material having the same transparency as the silicon wafer 1 as the measurement object with respect to the radiant energy in a specific wavelength range. As long as the condition is satisfied, for example, a silicon wafer other than the measurement target may be used, or the silicon wafer 1 itself as the measurement target may be used.

  This operation is repeated a plurality of times by changing the temperature of the reflector 2. That is, until the temperature measurement is completed (step S13), the heating temperature of the reflector 2 by the heating mechanism 6 is changed (step S14), and the first, second, and third temperatures are measured (step S12). When the necessary temperature data is obtained (step S13), the relationship between the error between the temperature of the silicon wafer 1 measured by the radiation thermometer 3 and the actual temperature of the silicon wafer 1 and the temperature of the reflector 2 is shown. The equation is calculated (step S15). The calculation of this relational expression is performed in the relational expression calculation unit 11 shown in FIG. 2 using, for example, the least square method.

  FIG. 4 is a graph showing errors between the temperature of the reflector 2, the temperature of the silicon wafer 1 measured by the radiation thermometer 3, and the actual temperature of the silicon wafer 1 measured by the thermocouple 5.

  In this figure, the horizontal axis indicates the temperature of the reflector 2 measured by the thermocouple 4, and the vertical axis indicates the temperature of the silicon wafer 1 measured by the radiation thermometer 3 and the actual temperature of the silicon wafer 1 measured by the thermocouple 5. The error is shown. In addition, the square mark in FIG. 4 has shown the data based on the temperature measured in the temperature measurement process (step S12) mentioned above. As described above, between the temperature of the silicon wafer 1 measured by the radiation thermometer 3 and the actual temperature of the silicon wafer 1 measured by the thermocouple 5, the radiation energy from the reflector 2 that passes through the silicon wafer 1 is reflected. The resulting difference arises. As shown in this graph, by plotting the error value when the temperature of the reflector 2 changes, a relational expression showing the relationship between the temperature of the reflector 2 and the error can be obtained.

  In the embodiment shown in this graph, the vertical axis indicates the error between the temperature of the silicon wafer 1 measured by the radiation thermometer 3 and the actual temperature of the silicon wafer 1 measured by the thermocouple 5, and the thermocouple 4 When the temperature of the reflector 2 measured by the above is X, the following equation can be approximately obtained.

Y = 0.0271X-0.2813
This relational expression is stored in the relational expression storage unit 12 shown in FIG. 2 (step S16).

  When the above preparation process is completed, the temperature of the silicon wafer 1 that is the actual measurement object is measured. FIG. 5 is a flowchart showing the temperature measurement process at this time.

  As shown in FIG. 1, the temperature measurement is performed in a state in which a silicon wafer 1 as a measurement object is arranged at a position facing the radiation thermometer 3 above the reflector 2 by a transfer device (not shown). At this time, first, the temperature of the silicon wafer 1 is measured by the radiation thermometer 3 (step S21). In parallel with this, the temperature of the reflector 2 is measured by the thermocouple 4 (step S22).

  Next, the relational expression stored in the relational expression storage unit 12 shown in FIG. 2 is read (step S23). Then, the temperature of the silicon wafer 1 measured by the radiation thermometer 3 is corrected (step S24). At this time, the temperature correction unit 13 shown in FIG. 2 calculates the error at that time by substituting the temperature of the reflector 2 measured in step S22 into the read relational expression, and measured by the radiation thermometer 3. The temperature is corrected by correcting the calculated temperature based on the calculated error. Thereby, the measurement temperature corresponding to the actual temperature of the silicon wafer 1 is certified. This measured temperature is used for controlling the processing of the silicon wafer 1 and is displayed on a display unit or the like as necessary.

  FIG. 6 is a table for explaining errors before and after correction when the present invention is applied.

  In the table shown in FIG. 6, the measured value of the silicon wafer 31 by the radiation thermometer 3 is b, the actual temperature of the silicon wafer 1 measured by the thermocouple 5 is a, and the temperature of the reflector 2 measured by the thermocouple 4 is measured. c, an error between the temperature of the silicon wafer 1 measured by the radiation thermometer 3 and the actual temperature of the silicon wafer 1 is ba, a correction value of the temperature obtained using the above-mentioned relational expression is d, and the radiation thermometer Bd is a corrected temperature obtained by correcting the measured value b of the temperature of the silicon wafer 1 by 3 with this correction value d, and an error between the corrected temperature and the actual temperature of the silicon wafer 1 measured by the thermocouple 5 Is indicated by a- (bd). In addition, the number in a table | surface shows temperature (degreeC). As can be seen from this table, the temperature of the silicon wafer 1 can be accurately measured within an error range of −0.7 ° C. to 0.8 ° C. by correcting the temperature using the relational expression. It becomes. As shown in the table shown in FIG. 6, when correction is not performed, an error of 5 ° C. at maximum occurs.

DESCRIPTION OF SYMBOLS 1 Silicon wafer 2 Reflector 3 Radiation thermometer 4 Thermocouple 5 Thermocouple 6 Heating mechanism 10 Control part 11 Relational expression calculation part 12 Relational expression memory | storage part 13 Temperature correction part

Claims (5)

The temperature of the measurement object that is transparent to the radiant energy in the specific wavelength range is at least partially overlapped with the measurement object spaced apart from the member that is not highly permeable to the radiant energy in the specific wavelength range in the vertical direction. A temperature measuring device for measuring from a direction perpendicular to the surface of the measurement object by a radiation thermometer disposed on the opposite side of the member with respect to the measurement object,
A temperature sensor for measuring the temperature of the member;
A relational expression storage unit for storing a relational expression indicating a relation between an error between a temperature of the measurement object measured by the radiation thermometer and an actual temperature of the measurement object, and a temperature of the member;
A temperature correction unit that corrects the temperature of the measurement object measured by the radiation thermometer using the relational expression stored in the relational expression storage unit and the temperature of the member measured by the temperature sensor;
A temperature measuring device comprising: The temperature measuring device according to claim 1,
A temperature measurement device comprising a transport mechanism for transporting the measurement object, wherein the radiation thermometer measures the temperature of the measurement object when the measurement object is transported by the transport mechanism. In the temperature measuring device according to claim 1 or 2,
The temperature sensor is a temperature measuring device that is a thermocouple that measures the temperature of the member in contact with the member. In the temperature measuring device according to any one of claims 1 to 3,
The measurement object is a temperature measurement device which is a silicon wafer. The temperature of the measurement object that is transparent to the radiant energy in the specific wavelength range is at least partially overlapped with the measurement object spaced apart from the member that is not highly permeable to the radiant energy in the specific wavelength range in the vertical direction. A temperature measurement method for measuring from a direction orthogonal to the surface of the measurement object by a radiation thermometer disposed on the opposite side of the member with respect to the measurement object,
While changing the temperature of the member, the first temperature which is the temperature of the equivalent of the measurement object measured by the radiation thermometer, and the temperature of the equivalent of the measurement object measured by the first temperature sensor A temperature measuring step of measuring a second temperature which is a third temperature which is a temperature of the member measured by a second temperature sensor;
From the first, second, and third temperatures obtained in the temperature measurement step, a relational expression showing the relationship between the error between the first temperature and the second temperature and the third temperature is shown. A relational expression calculation step for calculating a function;
When the temperature of the measurement object is measured by the radiation thermometer, the radiation thermometer is obtained by using the function calculated in the relational expression calculating step and the temperature of the member measured by the second temperature sensor. A temperature correction step of correcting the temperature of the measurement object measured by:
A temperature measuring method comprising:

Images