JPH11337413A - Apparatus and method for noncontact temperature measurement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a noncontact temperature measuring apparatus by which the surface temperature of an object to be measured can be measured precisely in a noncontact manner and which can be used repeatedly by a method wherein, when the surface temperature of the object to be measured is measured in a noncontact state, radiant heat from the surface of the object to be measured is received with good efficiency and the temperature is measured. SOLUTION: A noncontact temperature measuring apparatus is featured in such a way that a heat receiving plate 1 whose heat receiving face 6 is arranged so as to be faced with the surface of an object (a), to be measured, whose temperature is to be measured is provided and that a temperature measuring element in which a temperature measuring point 3 is arranged on the heat receiving plate 1 is provided. As a most universal temperature measuring element, a thermocouple 2 in which thermocouple wires 4, 5 composed of a pair of metal wires are bonded to the temperature measuring point 3 is used. Especially in a measurement at a high temperature, a thermocouple 2 in which a pair of thermocouples 4, 5 are composed of a platinum wire and a platinum-rhodium wire is used. The heat receiving face 6 on the heat receiving plate 1 is surface-treated in order to make its emissivity higher than other parts of the heat receiving plate 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature measuring device for measuring the surface temperature of a measured object using a temperature measuring element such as a thermocouple, and a temperature measuring method using the same. The present invention relates to a non-contact temperature measurement device suitable for non-contact temperature measurement of a flat surface and a temperature measurement method using the same.

[0002]

2. Description of the Related Art Thermocouples and resistance thermometers are used as temperature measuring means for measuring the temperature of an object and converting the temperature into an electric quantity such as a voltage. In particular, thermocouples occupy the mainstream of thermal measurement as contact-type measuring means. This is because thermocouples can be measured with high accuracy, have high stability, and can be manufactured at low cost. However, when the surface temperature of an object is measured with a thermocouple in a high temperature region, the measured value greatly changes due to heat flowing into a temperature measuring point at the tip of the thermocouple. For this reason, when many points are measured simultaneously, large variations occur. Further, when the measured object causes a chemical reaction with a metal wire constituting the thermocouple, there is a problem that accurate temperature measurement cannot be performed.

On the other hand, at 500 ° C. where heat radiation becomes active, a non-contact radiation thermometer for measuring radiation is used. Although this thermometer does not have the problems of the thermocouple, it requires correction of the radiation coefficient of the material and the radiation transmittance of the optical lens system. Must be moved in parallel with, or its correction is necessary. For this reason, the measurement accuracy is lower by about one digit than the thermocouple.

On the other hand, in a CVD thin film manufacturing apparatus which has come to be widely used in a semiconductor manufacturing apparatus and the like, a silicon wafer is mounted on a parallel heating disk and a thin film is formed by temperature control to produce a chip. . The process technology being advanced toward the 21st century is that the wafer diameter is 3
The temperature control is 800-100
In the temperature range of 0 ° C., high accuracy of ± 3 ° C. is required. However, at present there is no accurate means for measuring the surface temperature. In practice, there is a method of attaching a large number of platinum-platinum-rodium thermocouples on a dummy wafer with an adhesive, measuring the surface temperature of the dummy wafer, and thereby estimating the surface temperature of the target wear. Has been taken.

[0005]

However, since such a temperature measuring means cannot be used for the measurement again after the dummy wafer is measured only once, the life cycle is short and the reproducibility is small. On the other hand, a radiation thermometer is expensive because many correction items are numerically processed and displayed by a computer. Therefore, in the present invention, when measuring the surface temperature of the measurement object in a non-contact state, by efficiently receiving the radiant heat from the surface of the measurement object, by measuring this temperature,
It is an object of the present invention to provide a non-contact temperature measuring device that enables non-contact accurate measurement of the surface temperature of an object to be measured and that can be used repeatedly.

[0006]

According to the present invention, in order to achieve the above-mentioned object, a heat receiving plate 1 is disposed to face a surface of an object to be measured, and the temperature of the heat receiving plate 1 is measured. 1, a temperature measuring point 3 of a temperature measuring element such as a thermocouple 2 is attached, and a heat receiving surface 6 of the heat receiving plate 1 is arranged in a non-contact state in the vicinity of a surface to be measured of an object a to be measured. The surface temperature of an object is measured in a non-contact manner.

That is, the non-contact temperature measuring device according to the present invention comprises a heat receiving plate 1 having a heat receiving surface 6 opposed to the surface of the object to be measured whose temperature is to be measured; 3 is provided. The most common temperature measuring element is a thermocouple 2 in which thermocouple wires 4 and 5 composed of a pair of metal wires are joined at a temperature measuring point 3. In particular, for measurement at a high temperature, a thermocouple 2 in which a pair of thermocouples 4 and 5 are composed of a platinum wire and a platinum-rhodium wire is used.

The heat receiving surface 6 of the heat receiving plate 1 is at least twice as large as the cross-sectional area of the thermocouple wires 4 and 5 constituting the thermocouple, and the heat receiving surface 6 has a higher emissivity than other portions of the heat receiving plate 1. Perform surface treatment. The heat receiving plate 2 is preferably made of platinum or a platinum alloy. As a surface treatment for increasing the emissivity of the heat receiving surface 6, a platinum black treatment may be used. Using such a non-contact temperature measuring device, the heat receiving surface 2 of the heat receiving plate 1 was arranged to face the surface of the object a to be measured, and the temperature measuring point 3 was arranged on the heat receiving plate 1. The temperature measuring element is connected to a measuring instrument to measure the temperature of the heat receiving plate 1.

In the temperature measurement using this non-contact temperature measuring device, the heat receiving plate 1 receives radiant heat from the surface of the measured object a on its heat receiving surface 6, and the temperature of the heat receiving plate 6 is changed to the surface temperature of the measured object a. Is almost equal to Therefore, by measuring the temperature of the heat receiving plate 6 with a temperature measuring element such as the thermocouple 2, the temperature of the measured object a can be measured in a non-contact state.
It is preferable to arrange a reflector 9 on the side opposite to the heat receiving surface 6 of the heat receiving plate 1, and this reflector 9 is provided on the heat receiving surface 6 of the heat receiving plate 1.
More preferably, it is formed continuously from the opposite side to surround the periphery of the heat receiving plate 1. This reflector 9
Preventing diffusion of radiant heat radiated from the surface of the measurement object a,
Since most of the radiant heat can be reflected to the heat receiving plate 1, the heat receiving plate 1 almost exactly reflects the surface temperature of the measured object a.

[0010]

Embodiments of the present invention will now be described specifically and in detail with reference to the drawings.
FIG. 1 shows a basic configuration of a non-contact temperature measuring device according to the present invention. The measurement object a to be measured has a flat surface, such as a silicon wafer, and is a workpiece whose surface is processed at an element level at a high temperature. Such an object to be measured a is heated to a predetermined temperature by a resistance heater, not shown, or a filament for electron beam impact arranged thereunder, and in this state, the material compound is subjected to a thermochemical reaction on the surface. It is decomposed, accumulated and processed.

On the surface of the object a to be measured,
The heat receiving plate 1 is arranged so as to face. The side of the heat receiving plate 1 facing the surface of the measurement object a becomes the heat receiving surface 6. This heat receiving plate 1
Is a metal with good heat conductivity, and when measuring in a high temperature region,
A refractory metal having high chemical and physical stability at high temperatures is used. As a metal satisfying such conditions, for example, platinum or a platinum alloy can be used. The heat receiving surface 6 of the heat receiving plate 1 preferably has a particularly high emissivity, and is preferably subjected to a surface treatment for increasing the emissivity. When the heat receiving plate 1 is made of platinum or a platinum alloy, a platinum black treatment can be given as a surface treatment for increasing the emissivity. In this case, since the materials are of the same quality, the problem of peeling or cracking does not occur.

Further, the heat receiving plate 1 is provided with a temperature measuring point 3 of a temperature measuring element such as a thermocouple 2. The area of the heat receiving surface 6 of the heat receiving plate 1 is preferably at least twice the cross-sectional area of the thermocouple wires 4 and 5, and the temperature measuring point 3 of the thermocouple 1 is preferably provided at the center of the heat receiving plate 1.
The illustrated thermocouple uses a sheath-type thermocouple in which a pair of thermocouple wires 4 and 5 are housed in a sheath 7 such as a stainless steel tube and insulated by an inorganic insulating material 8 such as magnesia filled in the sheath 7. This sheath-type thermocouple is set up on the surface opposite to the heat receiving surface 6 of the heat receiving plate 1, and the temperature measuring point 3 to which the ends of the pair of thermocouple wires 4 and 5 are joined is embedded in the heat receiving plate 1. In addition, sheath 7
Is welded to the back surface of the heat receiving plate 1 and fixed so as to be orthogonal to the back surface of the heat receiving plate 1.

When the heat receiving plate 1 is made of platinum or a platinum alloy, it is preferable to use the thermocouple 2 whose thermocouple wires 4, 5 are made of platinum-platinum rhodium. Accordingly, there is no chemical reaction between the heat receiving plate 1 and the thermocouple wires 4 and 5 at a high temperature, and the heat receiving plate 1 can be used stably. The leads of the thermocouples 4 and 5 constituting the thermocouple 2 are connected to a measuring device via a zero-point compensation circuit (not shown), and the temperature is measured. The thermocouple 3 shown in FIG.
The thermocouple 2 is a non-grounded thermocouple 2 which is electrically floated in an insulating state in an insulating material 8.

Behind the heat receiving plate 1, a reflector 9 for reflecting the radiant heat radiated from the object to be measured a to the heat receiving plate 1 side is arranged. The reflector 9 is, for example, made of a metal whose reflection surface facing at least the heat receiving plate 1 side is a mirror surface, and has an inverted cup shape that surrounds the heat receiving plate 1 from behind the heat receiving plate 1. ing. The sheath 7 containing the thermocouple 2 passes through the center of the reflector 9.

In such a non-contact temperature measuring device,
The measurement object a is a heated object such as a silicon wafer, for example.
The measurement object a is heated from below, for example, in FIG. When the object a is heated to, for example, about 1,000 ° C., radiant heat is emitted from the surface of the object a. At this time, as shown in FIG. 1, when the heat receiving surface 6 of the heat receiving plate 1 is arranged in a non-contact state near the surface of the object to be measured a, the radiant heat radiated from the surface of the object to be measured a From the heat receiving plate 1. Since the heat receiving surface 6 is subjected to a process for increasing the emissivity, such as a platinum black process, the transfer of radiant heat is performed efficiently, and the temperature of the heat receiving plate 1 is measured a
Accurately reflect the temperature of the Therefore, by measuring the temperature of the heat receiving plate 6 with a temperature measuring element such as the thermocouple 2, the temperature of the measured object a can be measured.

A reflector 9 continuously formed so as to surround the periphery of the heat receiving plate 1 from the side opposite to the heat receiving surface 6 of the heat receiving surface 6 of the power receiving plate 1 is disposed, so that the reflector 9 becomes a surface of the object a. The diffusion of the heat radiated from is prevented, and most of the radiated heat is concentrated on the heat receiving plate 1. Therefore, the heat receiving plate 1
Reflects the surface temperature of the measured object a almost exactly.

In FIG. 2, a plurality of combinations of the heat receiving plate 1 and the thermocouple 2 are prepared, and the heat receiving plates 1 are arranged so that the respective heat receiving surfaces 6 face each other at a plurality of locations on the surface of the measured object a. Things. In this way, for the measurement object a such as a silicon wafer having a large surface area, the temperature can be measured at a plurality of locations of the measurement object a at the same time by using the plurality of heat receiving plates 1.

As the reflector 9 shown in FIG. 2, an inverted tray having a large flat area and covering the plurality of heat receiving plates 1 at the same time is used. On the other hand, a reflector 9 may be provided for each heat receiving plate 1 as shown in FIG.
In the above embodiment, a thermocouple is used as a temperature measuring element, but it is of course possible to use other electric temperature measuring means such as a temperature measuring resistor as a temperature measuring element. is there.

[0019]

Next, referring to FIGS. 2 and 3, an embodiment of the present invention will be described with specific numerical values. FIG. 3 shows a plane of a measurement object a which is a silicon wafer having a diameter of 300 mm. As shown in FIG. 3, the above-mentioned heat receiving plates 1 are arranged at intervals of 120 ° on the center of the object to be measured and three concentric circles around this center, and their heat receiving surfaces 6 (see FIG. 2).
Was placed 3 mm away from the measurement object a and opposed to each other. A longitudinal side view in this state is as shown in FIG. The thermocouples 2 (see FIGS. 1 and 2) each having the temperature measuring contacts 3 (see FIG. 1) embedded in the heat receiving plate 1 were connected to a measuring instrument via a zero-point compensation circuit.

As shown in FIG. 1, for the purpose of comparing the measured temperature values, a temperature measuring contact 11 of a thermocouple 10 made of platinum-platinum rhodium is buried in three places on the surface of the measured object a. Reference numeral 10 was connected to a measuring instrument via a zero-point compensation circuit. Put these measurement object a and heat receiving plate 1 etc. in vacuum,
While applying an accelerating voltage to the measurement object a, the lower surface of the measurement object was bombarded with thermoelectrons from the filament, and the electron shock was used to uniformly heat the measurement object at a temperature of 1,000 ° C.

In the stable state of the object to be measured a, the thermocouples 2 in which the temperature measuring contacts 3 are embedded in the heat receiving plate 1 are respectively arranged at ten positions, and the thermocouple in which the temperature measuring point 11 is directly embedded in the surface of the object to be measured a. FIG. 3 shows the results of the temperature measured for each pair. From this result, the heat receiving plate 1 at the center of the plane of the measurement object a
Is 1006.1 ° C., and the temperature measured by the surrounding heat receiving plate 1 is 1004.3 ° C. to 1011.
7 ° C., and the variation was almost within ± 3 ° C. In addition, a thermocouple 10 in which a temperature measuring point 11 is directly embedded in the surface of the object a.
The temperature measured at 992.3 ° C. to 10.00.0 ° C.
As a result, the temperature measured values varied even on the wafer having the same temperature distribution.

As described above, the heat receiving plate 1 that is not in contact with the measurement object a
And the temperature measured by the thermocouple 10 in which the temperature measuring point 11 was directly embedded in the surface of the measured object a, were almost the same. Therefore, it was confirmed that the non-contact temperature measurement device according to the present invention can measure the temperature with the same accuracy as the temperature measurement by the thermocouple 10 in which the temperature measuring junction is embedded in the conventional measurement object a. Moreover, it is clear that the variation in the measured temperature value is much smaller than that of the thermocouple.

[0023]

As described above, in the non-contact temperature measuring apparatus and the temperature measuring method using the same according to the present invention, the radiant heat from the surface of the object is measured when the surface temperature of the object is measured in a non-contact state. By efficiently receiving heat and measuring this temperature, it becomes possible to measure the surface temperature of the object to be measured in a non-contact manner at multiple points and simultaneously. Moreover, the non-contact temperature measuring device can be used repeatedly.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view of a main part showing an example of a non-contact temperature measuring device and a temperature measuring method using the same according to the present invention.

FIG. 2 is a vertical sectional side view of a main part showing another example of a non-contact temperature measuring device and a temperature measuring method using the same according to the present invention, in which a plurality of thermocouples are used as heat receiving plates.

FIG. 3 shows an example of a non-contact temperature measuring device and a temperature measuring method using the same according to the present invention, in which a non-contact temperature measuring device in which a heat receiving plate and a thermocouple are combined and a thermocouple is directly embedded in the surface of an object to be measured a It is a top view of the measured object which shows the measured result.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat receiving plate 3 Temperature measuring point 4 Thermocouple wire 5 Thermocouple wire 2 Thermocouple 6 Heat receiving surface of heat receiving plate a Measurement object 9 Reflector

Claims (9)

[Claims] 1. A non-contact temperature measuring device for measuring the surface temperature of a measured object (a) in a non-contact manner, wherein the heat receiving plate (1) is arranged to face the surface of the measured object (a) whose temperature is to be measured. ), And a temperature measuring element having a temperature measuring point (3) arranged on the heat receiving plate (1). 2. A non-contact thermocouple, wherein the temperature measuring element is a thermocouple (2) in which thermocouple wires (4) and (5) each comprising a pair of metal wires are joined at a temperature measuring point (3). Temperature measuring device. 3. The non-contact temperature measuring device according to claim 2, wherein the thermocouple wires (4) and (5) constituting the thermocouple (2) are made of a platinum wire and a platinum rhodium wire, respectively. . 4. The heat receiving surface (6) of the heat receiving plate (1) is at least twice as large as the cross-sectional area of the thermocouple wires (4) and (5) constituting the thermocouple. 3. The non-contact temperature measuring device according to 3. 5. The heat receiving surface (6) of the heat receiving plate (1) facing the surface of the measurement object (a) has been subjected to a surface treatment with a higher emissivity than other portions of the heat receiving plate (1). The non-contact temperature measuring device according to any one of claims 1 to 4, wherein 6. The non-contact temperature measuring device according to claim 5, wherein the heat receiving plate (1) is made of platinum or a platinum alloy, and the heat receiving surface (6) is treated with platinum black. 7. Non-contact temperature measurement according to claim 1, wherein a reflector (9) is arranged on a side of the heat receiving plate (1) opposite to the heat receiving surface (6). apparatus. 8. The reflector (9) is formed continuously from the side opposite to the heat receiving surface (6) of the heat receiving plate (1) so as to surround the periphery of the heat receiving plate (1). 1-5
The non-contact temperature measuring device according to any one of the above. 9. A heat receiving surface (6) of a heat receiving plate (1) on a surface of the object (a) to be measured using the non-contact temperature measuring device according to any one of claims 1 to 8. ) Are arranged facing each other, and a temperature measuring element having a temperature measuring point (3) arranged on the heat receiving plate (1) is connected to a measuring instrument to measure the temperature of the heat receiving plate (1). Contact temperature measurement method.