JP5098045B2 - Piezoelectric temperature sensor and silicon wafer temperature measurement jig - Google Patents

Description

  The present invention relates to a temperature sensor suitable for measuring the surface temperature of a silicon wafer, for example, in a heat processing step when manufacturing a semiconductor using a silicon wafer substrate, and in particular, has a heat resistance that can withstand high temperatures during heat processing. Therefore, the present invention provides a silicon wafer temperature measurement jig suitable for measuring the surface temperature of a silicon wafer or the like by means of a piezoelectric temperature sensor having an integrated piezoelectric element and antenna.

Currently, many electronic devices that we use use integrated circuits (ICs).
In this integrated circuit, semiconductor elements are integrated to form various circuit boards. Usually, a large number of integrated circuits (ICs) are formed on a silicon wafer substrate made of a single crystal version of silicon (Si). The IC chip formed by dividing the IC into the package is housed in a package and incorporated into an electronic device or the like.

In order to form an integrated circuit using this silicon wafer, an enormous number of manufacturing steps are required, but can be roughly classified into a pre-process and a post-process.
The pre-process includes a cleaning process, a film forming process, a lithography process, an impurity diffusion process, and the like, and is a process for forming an IC chip on a silicon wafer.
The post-process is a process in which the final inspection of the IC chip on the silicon wafer is performed to complete the product.

  The above-described pre-process includes a process of heating the silicon wafer such as a process of growing a silicon oxide film and an impurity diffusion process, for example, a heat processing process performed in a high-temperature atmosphere of 250 ° C. or higher. In order to perform this heat processing step, a temperature control technique is required in which the entire surface of the silicon wafer is heated to a predetermined temperature or the heated temperature is maintained for a predetermined time. In recent years, silicon wafers have been increased in size in order to manufacture high-density integrated circuits in large quantities, and more precise work is required in this heating process.

In this heat processing step, if the surface of the silicon wafer is not heated uniformly, there is a possibility that the quality of the finished product of the IC chip taken out from the completed integrated circuit may be uneven.
The high yield of how many good IC chips can be taken out from a completed integrated circuit is a problem that greatly affects the manufacturing cost. Therefore, in the heat processing process, it is necessary to measure the temperature at multiple points on the silicon wafer surface in a short time, measure whether the entire silicon wafer is heated uniformly, and control the temperature to keep the surface temperature of the silicon wafer uniform. It becomes.

  When measuring the surface temperature of a heated silicon wafer, a temperature sensor whose physical constant changes with respect to the temperature change is used, and by electrically detecting the characteristics of this temperature sensor, The surface temperature is being measured. However, a temperature sensor that measures the surface temperature of a silicon wafer heated in a high-temperature atmosphere is required to have considerable heat resistance. As a temperature sensor used at this time, a temperature sensor using a method of measuring an electromotive voltage of a thermocouple, a platinum resistance band whose electric resistance changes depending on temperature, a temperature sensitive element such as a thermistor, and the like are known. However, as a more accurate temperature sensor (temperature measuring element), a quartz crystal temperature sensor that electrically measures a change in resonance characteristics, such as a quartz piece, is known.

The following cited reference 1 describes a crystal temperature sensor using a crystal as a piezoelectric element in order to perform temperature measurement in a cryogenic region. As an example of this crystal temperature sensor, the additional impedance element and the crystal resonator are sealed in a container whose inside is kept airtight, and the lead terminals of the additional impedance element and the crystal resonator are provided outside the container. It is formed in this way.
In the case of this cited reference, a bulk element that separates a resistor and a coil is used as an impedance element, and a quartz oscillator with a strip-shaped crystal piece with electrodes attached to it is used. is doing. Then, one electrode attached to the crystal resonator and one electrode forming the impedance element are common electrodes, and the common electrode, the crystal resonator, and the impedance element lead terminals are provided. A temperature sensor is formed.
Patent Document 1 describes that by using such a crystal temperature sensor, it is possible to measure the temperature in the cryogenic region with high accuracy and high resolution.

Japanese Patent Laid-Open No. 3-57932

  However, the quartz temperature sensor described in the cited document 1 can perform highly accurate temperature measurement when measuring the temperature in the extremely low temperature region, but it is difficult to measure the temperature at a high temperature as in the heating process in the integrated circuit manufacturing process. When measuring temperature in an atmosphere, there is a problem with heat resistance.

In addition, since the impedance element and the crystal resonator are separately separated as the crystal temperature sensor, the size thereof is increased.
When measuring the surface temperature of a silicon wafer in a heat processing step or the like, if the surface temperature of the silicon wafer can be measured as many points as possible, highly accurate information on the surface temperature of the silicon wafer can be obtained. .
However, in the quartz temperature sensor described in the cited document 1, it is extremely difficult to measure the surface temperature of multiple points of the silicon wafer due to its shape.

The piezoelectric temperature sensor of the present invention has been made in view of such problems, and a piezoelectric vibration region in which excitation electrodes are arranged on both surfaces;
An antenna region that is spaced apart from the periphery of the piezoelectric vibration region and provided with a loop-shaped conductor on the surface thereof, heat resistance that is disposed so as to cover the piezoelectric vibration region and the antenna region, and An electromagnetic wave transmissive container portion, the piezoelectric vibration region and the antenna region are coupled by one or more bridge portions, and the excitation electrode and the loop-shaped conductor are connected via the bridge portions. Are combined.

The piezoelectric vibration region and the antenna region are separated from each other, and the bridging portion for connecting them is formed by cutting a single flat piezoelectric material.
The outer periphery of the piezoelectric vibration region and the antenna region is formed in a substantially circular shape.
The outer periphery of the piezoelectric vibration region and the antenna region is formed in a square shape.
The container portion is configured by overlapping two concave lids on the periphery of the antenna region.

The container portion is formed of a heat resistant silicon material.
The piezoelectric vibration region, the antenna region, and the bridging portion are constituted by a crystal piece.
The piezoelectric vibration region, the antenna region, and the bridging portion are made of langasite or gangatite.
In addition, by fixing a plurality of piezoelectric temperature sensors at predetermined positions on the surface of the silicon wafer, it can be used as a jig for performing temperature characteristics when the silicon wafer is heated.

In the piezoelectric temperature sensor of the present invention, the piezoelectric vibration region and the antenna region are connected by a bridge portion, and the excitation electrodes disposed on both surfaces of the piezoelectric vibration region and the loop-shaped conductor provided in the antenna region are combined. As a result, the excitation electrode and the conductor are integrated. In addition, by covering the excitation electrode, antenna area, and bridging portion with a heat-resistant container that can transmit electromagnetic waves, it can withstand high-temperature atmosphere and send and receive signals to and from external devices. Can be done.
Therefore, a plurality of piezoelectric temperature sensors are arranged on the surface of the silicon wafer in the heat processing step performed in a high temperature atmosphere in the manufacturing process of the integrated circuit, and can measure the temperature at multiple points on the surface of the silicon wafer. . The piezoelectric temperature sensor, for example, wirelessly transmits the measured surface temperature of the silicon wafer to an external device and receives a signal from the external device, so that it is effective even in a high-temperature furnace. Available.

Examples for carrying out the present invention will be described below.
FIG. 1 is a diagram for explaining the configuration of a piezoelectric temperature sensor 10 as a first embodiment of the present invention.
In FIG. 1, FIG. 1A is a view from the front of the piezoelectric temperature sensor 10 seen through a container portion (a silicon cover 17 described later). FIG. 1B is a perspective view of the piezoelectric temperature sensor 10 when a part of the container (hereinafter referred to as a silicon cover 17) is cut along a dotted line A shown in FIG. FIG.1 (c) is sectional drawing at the time of cutting the piezoelectric temperature sensor 10 by the dotted line A shown to Fig.1 (a).

The piezoelectric temperature sensor 10 of the present invention uses a piezoelectric vibrator. Examples of the piezoelectric vibrator include quartz crystal, langasite, gangatite, lithium tantalate, lithium niobate, zinc oxide, and the like.
(Langasite = La3Ga5SiO14)
Then, by installing the piezoelectric temperature sensor 10 at a predetermined location on the silicon wafer, the piezoelectric temperature sensor 10 can be used as a jig for performing temperature control during the processing of the silicon wafer.

In the piezoelectric temperature sensor 10 of the first embodiment, as shown in FIG. 1A, the outer periphery of the piezoelectric element 11 is formed in a square shape. The illustrated piezoelectric element 11 includes slits 12 and 12 at two locations by dry edging, wet edging, or other thin film technology, and the piezoelectric element 11 is divided into a piezoelectric vibration region 11a and an antenna region 11b. ing.
In the case of the first embodiment, the piezoelectric vibration region 11a and the antenna region 11b are connected to each other at two locations of a first bridging portion 15a and a second bridging portion 15b described later.

As shown in FIG. 1C, the piezoelectric vibration region 11a is provided with electrodes 13a and 13b as excitation electrodes on both surfaces. The electrodes 13a and 13b are made of a material having a high melting point such as platinum (Pt), and are formed on the respective surfaces of the piezoelectric vibration region 11a by sputtering, vapor deposition, or the like.
As will be described later, the piezoelectric vibration region 11a is excited by a resonance frequency or a signal in the vicinity of the resonance frequency (transmitted radio wave) supplied from the outside, and vibrates even after the signal disappears from the outside. It is an area. This vibration becomes reverberation vibration according to temperature, and the electrode 13a and the electrode 13b can transmit this reverberation vibration.

As shown in FIG. 1A, a loop antenna that is a loop-shaped conductor is disposed in the antenna region 11b. That is, the antenna 14a is arranged so as to surround the outside of the slit 12 in a loop shape, thereby forming a loop antenna.
And the antenna lead 14b is arrange | positioned as shown to FIG.1 (a) (b) (c) in the surface on the opposite side to the surface of the antenna area | region 11b where the antenna 14a is arrange | positioned. The antenna 14a and the antenna lead 14b are made of a material having a high melting point such as platinum (Pt) like the electrodes 13a and 13b, and are formed on the respective surfaces of the antenna region 11b by sputtering or vapor deposition. Is.
The antenna 14a and the antenna lead 14b receive a signal at or near the resonance frequency transmitted from the outside, excite the piezoelectric element 11 with the electrode 13a and the electrode 13b, and post-excited reverberation vibration. Are transmitted to the temperature measuring device 20 side through the small transmitting / receiving antenna 25 and the large transmitting / receiving antenna 28 described in the above.

The piezoelectric vibration region 11a and the antenna region 11b are connected by the first bridge portion 15a and the second bridge portion 15b, and one terminal of the loop antenna 14a is connected to the front electrode 13a. The other terminal of the antenna 14a is connected to the antenna lead 14b connected through the back side electrode 13b and the second bridging portion 15b.
In this case, the antenna 14a and the antenna lead 14b are connected via the through hole 16 as shown in FIG.
As is well known, the through hole 16 has a conductive film formed inside the hole and is formed so as to penetrate the piezoelectric element 11.

The piezoelectric element 11 including the piezoelectric vibration region 11a and the antenna region 11b which are mechanically separated as described above, and the first bridging portion 15a and the second bridging portion 15b are illustrated in FIGS. 1B and 1C. As shown in FIG. 2, the silicon cover 17 covers the substrate. The silicon cover 17 has a rectangular shape in accordance with the rectangular outer periphery of the piezoelectric element 11, and a recess 18 shown in FIG. 1C is formed at the center of the surface on which the silicon covers 17 are overlapped. Has been.
The concave portion 18 is provided to secure a space for the electrodes 13a and 13b in consideration of the thicknesses of the electrodes 13a and 13b disposed in the piezoelectric vibration region 11a when the piezoelectric element 11 is sandwiched between the silicon covers 17. It is what has been. In addition to the recess 18, the silicon cover 17 has a space for preventing the silicon cover 17 from contacting the antenna 14 a and the antenna lead 14 b when the piezoelectric element 11 is sandwiched.

When covering the piezoelectric element 11 with the silicon cover 17, the silicon cover 17 is intermolecularly sandwiched between the silicon cover 17 as shown in FIGS. 1B and 1C. Bond and bond to cover.
The material of the silicon cover 17 may be any material that has heat resistance and transmits electromagnetic waves. For example, when the wafer to be measured is silicon, silicon (Si) is preferable.

The piezoelectric temperature sensor 10 according to the first embodiment having the configuration described with reference to FIG. 1 includes a piezoelectric element 11 of a piezoelectric vibrator, an antenna 14a for transmitting and receiving with an external device, and an antenna lead 14b. Thus, the temperature sensor can be reduced in size. Since the piezoelectric temperature sensor 10 is downsized, the temperature can be measured using a plurality of piezoelectric temperature sensors 10 when measuring a wide range of temperatures of the measurement object.
Further, since it is covered with the silicon cover 17 made of a heat-resistant material, it can withstand work processes in a high-temperature atmosphere.

Next, the configuration of the piezoelectric temperature sensor 10 of the second embodiment will be described with reference to FIG.
FIG. 2A is a view of the silicon cover 17 seen through from the front of the piezoelectric temperature sensor 10. FIG. 2B is a perspective view of the piezoelectric temperature sensor 10 when a part of the silicon cover 17 is cut along a dotted line A shown in FIG. FIG. 2C is a cross-sectional view of the piezoelectric temperature sensor 10 cut along the dotted line A shown in FIG.
The piezoelectric temperature sensor 10 according to the second embodiment includes the piezoelectric temperature sensor 10 according to the first embodiment described with reference to FIG. 1, the piezoelectric element 11 used in the piezoelectric vibrator, and the outer periphery of the silicon cover 17. The configuration is the same except that the shape is circular. In addition, the same code | symbol is attached | subjected to the same part as the structure of the piezoelectric temperature sensor 10 of 1st Embodiment, and detailed description is abbreviate | omitted.

Secondly, in the piezoelectric temperature sensor 10 according to the embodiment, as shown in FIGS. 2A and 2B, the piezoelectric element 11 has slits 12 at two locations, and the piezoelectric vibration region 11a and the antenna are provided. The piezoelectric vibration region 11a and the antenna region 11b are connected by a first bridge portion 15a and a second bridge portion 15b.
Electrodes 13a and 13b are disposed on both surfaces of the piezoelectric vibration region 11a. On one surface of the antenna region 11b, an antenna 14a that surrounds the outer periphery of the slit 12 in a loop shape is arranged as a loop antenna, and one end of the antenna 14a is connected to the first bridging portion 15a. It is connected to the electrode 13a through.
The antenna lead 14b is disposed on the other surface of the antenna region 11b other than the surface where the loop-shaped antenna 14a is disposed, and one end of the antenna region 11b is connected to the electrode 13b through the second bridging portion 15b. As shown in FIG. 2C, the other end is connected through the through hole 16 to the end not connected to the electrode 13a of the loop antenna 14a.

  As with the piezoelectric temperature sensor 10 of the first embodiment, the electrode 13a, the electrode 13b, the antenna 14a, and the antenna lead 14b are made of a material having a high melting point, such as platinum (Pt), by sputtering or vapor deposition. It is formed on each surface of the piezoelectric vibration region 11a and the antenna region 11b.

Further, the piezoelectric element 11 including the piezoelectric vibration region 11a, the antenna region 11b, and the first bridging portion 15a and the second bridging portion 15b is covered with a silicon cover 17 that has heat resistance and transmits electromagnetic waves. The material of the silicon cover 17 in the second embodiment is also adapted to the measurement object, but can be adapted to the material in the case of other measurement objects.
The outer periphery of the silicon cover 17 is circular like the piezoelectric element 11, and the center of the surface on which the silicon covers 17 are overlapped is the same as that of the silicon cover 17 described in FIG. The concave portion 18 shown in FIG.
Also in the case of the silicon cover 17 of FIG. 2, a space 18 is provided to prevent the silicon cover 17 from contacting the antenna 14a and the antenna lead 14b when the piezoelectric element 11 is covered.
Then, when covering the piezoelectric element 11 of FIG. 2, the silicon covers 17 are bonded by intermolecular bonds.

Next, FIG. 3 shows a modification of the piezoelectric temperature sensor 10 shown in FIG. 2, which is the second embodiment. In addition, when the same structure as the structure demonstrated with the piezoelectric temperature sensor 10 of FIG. 2 is shown in FIG. 3, the same code | symbol is attached | subjected and description is abbreviate | omitted.
3A, the piezoelectric element 11 has three slits 12, and the piezoelectric vibration region 11a and the antenna region 11b include a first bridging portion 15a, a second bridging portion 15b, and a third bridging portion 15c. The piezoelectric temperature sensor 10 is connected at three locations. The piezoelectric temperature sensor 10 of FIG. 3A has the same configuration as the piezoelectric temperature sensor 10 of FIG. 1 except that neither the antenna 14a nor the antenna lead 14b passes through the third bridging portion 15c. The same effect can be obtained.

  The piezoelectric temperature sensor 10 of FIG. 3B is another example of the second embodiment, and the piezoelectric element 11 has four slits 12 and includes a piezoelectric vibration region 11a and an antenna region 11b. However, it is connected in four places, the 1st bridge part 15a, the 2nd bridge part 15b, the 3rd bridge part 15c, and the 4th bridge part 15d. The piezoelectric temperature sensor 10 shown in FIG. 3B is configured such that neither the antenna 14a nor the antenna lead 14b passes through the third bridging portion 15c and the fourth bridging portion 15d. It has the same configuration as the sensor 10 and can obtain the same effect.

In the piezoelectric temperature sensor 10 according to the first embodiment, the piezoelectric temperature sensor 10 having three and four bridging portions as in the modification of the second embodiment is also conceivable. In the first and second embodiments, the piezoelectric temperature sensor 10 having one bridging portion is also conceivable.
In this case, the antenna 14a and the electrodes 13a and 13b may be connected using the front and back surfaces of one bridge portion.

Also in the piezoelectric temperature sensor 10 of the second embodiment described above, as in the first embodiment, the piezoelectric element 11 is integrated with the antenna 14a and the antenna lead 14b so that the temperature sensor can be downsized. In the case where the temperature of a wide range of the measurement object is measured, the measurement can be performed using the plurality of piezoelectric temperature sensors 10.
Further, by covering the piezoelectric element 11 with the heat-resistant silicon cover 17, it can withstand high temperatures.

Here, as an example in which the piezoelectric temperature sensor 10 of the present invention is actually used, for example, in the process of heating in a high temperature atmosphere by heating a processing silicon wafer in the process of manufacturing an integrated circuit (IC). It is thought that it is used for.
In this heating process, the piezoelectric temperature sensor 10 is installed on the surface of a silicon wafer for temperature measurement used as a jig, measures the surface temperature, and based on the measured temperature, the surface temperature of the silicon wafer for processing is determined. It is used as a temperature sensor for controlling the heating temperature so as to be uniform.

There are several possible methods for installing the piezoelectric temperature sensor 10 on the surface of a silicon wafer for temperature measurement, which is a jig for temperature measurement. For example, there is a method as shown in FIG.
FIG. 4A shows an installation example in which the piezoelectric temperature sensor 10 is embedded in a part of the surface of the measurement silicon wafer 19 serving as a jig. In FIG. 4A, about half of the piezoelectric temperature sensor 10 is embedded in the measurement silicon wafer 19 in the vertical direction.
FIG. 4B shows a method in which the entire piezoelectric temperature sensor 10 is installed so as to be sandwiched inside the measurement silicon wafer 19.
As will be described later, a plurality of piezoelectric temperature sensors 10 fixed to the measurement silicon wafer 19 are arranged at predetermined positions when the processing wafer is large.

  In this way, the piezoelectric temperature sensor 10 is placed on the measurement silicon wafer 19 to measure the temperature. In the piezoelectric temperature sensor 10 of the present invention, the silicon cover 17 is used to cover the piezoelectric element 11 and the like. I use it. This is intended to suppress measurement errors by using a heat-resistant material that is close to the physical characteristics of the material of the object to be measured when measuring temperature with the piezoelectric temperature sensor 10.

Next, an outline of a temperature measurement method when the piezoelectric temperature sensor 10 of the present invention is used will be described with reference to FIGS.
A silicon wafer multi-point temperature measuring method 100 for a multi-point portion of a silicon wafer shown in FIG. 5 measures the surface temperature of the measurement silicon wafer 19 and adjusts the temperature so that the surface temperature of the measurement silicon wafer 19 is uniform. Is what you do.
5, 6, and 7, the piezoelectric temperature sensor 10 described in FIG. 4A is partially embedded in the measurement silicon wafer 19. Of course, FIG. Alternatively, the piezoelectric temperature sensor 10 described in b) may be sandwiched between the measurement silicon wafers 19.
5, 6, and 7, the rectangular piezoelectric temperature sensor 10 according to the first embodiment of the present invention will be described. This is also the circular piezoelectric temperature according to the second embodiment. The sensor 10 may be used.

In the silicon wafer multipoint temperature measuring method 100 shown in FIG. 5, first, a temperature measuring device 20 and an impedance matching device 21 are installed outside the chamber and connected to each other by a coaxial cable 22. The temperature measuring device 20 includes a sweep transmitter, a phase detector, a current measuring device, a directional coupler, and the like whose frequency changes within a predetermined range.
Further, the impedance matching unit 21 and quartz 26 in the chamber or the small transmitting / receiving antennas 25a, 25b, 25c, 25d, 25e, 25f,. And a single-core or multi-core heat-resistant cable 23 (hereinafter, also simply referred to as a heat-resistant cable) covered with a coaxial cable 22.
At this time, as a cable used to connect each other, a coaxial cable 22 is used outside the chamber as shown in the figure, and a multi-core heat-resistant cable 23 that can withstand high temperatures is used inside the chamber. These two cables are used by being connected by a connector 24 at the boundary between the outside of the chamber and the inside of the chamber.

  In the silicon wafer multi-point temperature measurement method 100 of FIG. 5, a plurality of piezoelectric temperature sensors 10a, 10b, 10c are used as temperature sensors for measuring the surface temperature of the measurement silicon wafer 19 serving as a temperature measurement jig. 10d, 10e, 10f... Are used. The piezoelectric temperature sensors 10a, 10b, 10c, 10d, 10e, 10f,... Are measured at a predetermined location on the surface of the measurement silicon wafer 19, for example, a temperature distribution as shown in FIG. Embed in the point.

And each small transmitting / receiving antenna 25a, 25b, 25c, 25d, 25e, 25f,... Coated with quartz 26 on the concentric axes of the piezoelectric temperature sensors 10a, 10b, 10c, 10d, 10e, 10f,. To be installed.
Further, the quartz 26 covering the small transmitting / receiving antennas 25a, 25b, 25c, 25d, 25e, 25f,... Is heat resistant and is made of quartz 26 if it is made of a material that can withstand the temperature of the heating process. It does not have to be.

In addition, hereinafter, a plurality of piezoelectric temperature sensors 10a, 10b, 10c, 10d, 10e, 10f,... Are connected to a channel Ch1 (piezoelectric temperature sensor 10a), a channel Ch2 (piezoelectric temperature sensor 10b), and a channel as necessary. Explanation will be made as Ch3 (piezoelectric temperature sensor 10c), channel Ch4 (piezoelectric temperature sensor 10d), channel Ch5 (piezoelectric temperature sensor 10e), channel Ch6 (piezoelectric temperature sensor 10f),.
In the following, small transmitting / receiving antennas 25a, 25b, 25c, 25d, 25e, 25f..., Piezoelectric temperature sensors 10a, 10b, 10c, 10d, 10e, 10f..., Channel Ch1, channel Ch2, channel Ch3, When describing the channel Ch4, the channel Ch5, the channel Ch6,..., When there is no need to describe them individually, the description will be made as the small transmitting / receiving antenna 25, the piezoelectric temperature sensor 10, and the channel Ch.

In the silicon wafer multipoint temperature measurement method 100 shown in FIG. 5, as a method of measuring the temperature of the measurement silicon wafer 19, first, the temperature measurement device 20 starts from an arbitrary frequency band step by step for each channel Ch. A sweep signal wave to be transmitted while stepping up the frequency band is transmitted via the small transmitting / receiving antenna 25.
For example, in the channel Ch1, when the frequency of the sweep signal wave is in the vicinity of the resonance frequency of the piezoelectric vibrator, a reverberation vibration wave corresponding to the temperature at that time is transmitted immediately after the sweep signal wave is stopped. When each of the small transmitting / receiving antennas 25 receives this reverberation vibration wave and the reverberation vibration wave from each channel Ch is obtained, the temperature measuring device 20 calculates the temperature at multiple points based on the frequency of each reverberation vibration wave. To do.

  In this way, the temperature measuring device 20 obtains reverberation vibration waves in order from all the channels Ch installed on the measurement silicon wafer 19, and the temperature of each channel Ch, that is, on the measurement silicon wafer 19. The temperature at each point is calculated. Then, the temperature measuring device 20 transmits the calculation result to the heating control device 90. The heating control device 90 controls the heating means 91 so that the temperature of the measurement silicon wafer 19 heated in the chamber becomes uniform. The temperature is adjusted. The heating control data for each point formed from the calculated temperature data is preferably stored in any one of the above devices.

In the silicon wafer multipoint temperature measurement method 100 of FIG. 5, in order for the temperature measurement device 20 to obtain a reverberation vibration wave for each channel Ch, a small transmitting / receiving antenna 25 is arranged on the concentric axis of each channel Ch. It is also possible to observe the temperature of all channels Ch in real time.
That is, all the piezoelectric temperature sensors 10 can observe the temperature of the measurement silicon wafer 19 in a short time.
Further, in this case, if the temperature measuring device 20 is provided corresponding to all the small transmitting / receiving antennas 25, it is possible to know which channel Ch has the frequency of the reverberation vibration wave. For this reason, as the piezoelectric vibrator of the piezoelectric temperature sensor 10, piezoelectric vibrators having the same resonance frequency characteristics can be used.
Further, if the temperature measurement device 20 can perform measurement by switching the temperature for each channel Ch of the small transmission / reception antenna 25, even if the temperature measurement is performed by a plurality of channels Ch, it can be observed by one unit. it can.
Furthermore, since the piezoelectric temperature sensor 10 and the small transmission / reception antenna 25 transmit and receive wirelessly, it is not necessary to fold the cord on the measurement silicon wafer 19.

The silicon wafer multipoint temperature measuring method 100 shown in FIG. 6 has the same configuration as the silicon wafer multipoint temperature measuring method 100 described with reference to FIG. 5 except that the position where the small transmitting / receiving antenna 25 is installed is different. .
In FIG. 6, the same components as those shown in FIG.

In the silicon wafer multipoint temperature measuring method 100 of FIG. 6, a temperature measuring device 20 and an impedance matching device 21 are installed outside the chamber and connected to each other by a coaxial cable 22, and the impedance matching device 21 and the impedance matching device 21 are installed in the chamber. A small transmitting / receiving antenna 25 covered with quartz 26 is connected by a multi-core heat-resistant cable 23. At this time, the small transmitting / receiving antenna 25 is installed so as to be disposed on the outer circumference of the piezoelectric temperature sensor 10 embedded in the measurement silicon wafer 19 as illustrated.
In the method of planarly arranging the small transmitting / receiving antenna 25 on the outer circumference of each piezoelectric temperature sensor 10, there is no extra space in the vertical direction of the measurement silicon wafer 19, and the small transmitting / receiving antenna 25 can be installed. Applicable when it is not possible.
As for the cable connecting the impedance matching unit 21 and the small transmitting / receiving antenna 25, the coaxial cable 22 is used outside the chamber and the multi-core heat-resistant cable 23 is used inside the chamber with the connector 24, as in the case of FIG. Connect.

In the silicon wafer multipoint temperature measuring method 100 of FIG. 6 as well, the method of measuring the temperature of the measurement silicon wafer 19 is the same as that of the silicon wafer multipoint temperature of FIG. The temperature can be measured by the same method as the measuring method 100.
In the silicon wafer multipoint temperature measuring method 100 of FIG. 6 as well, by arranging the small transmitting / receiving antennas 25 as shown, the temperatures of all the channels Ch can be measured in real time, and each channel Ch is measured. Therefore, it is possible to observe with one temperature measuring device 20.

Further, the temperature measuring device 20 shown in FIG. 6 transmits the calculation result to the heating control device 90 in the same manner as the temperature measuring device 20 shown in FIG. 5, and the heating control device 90 controls the heating means 91 to control the chamber. The temperature inside is adjusted.
In the case of the silicon wafer multi-point temperature measuring method 100 of FIG. 6, a piezoelectric vibrator having the same resonance frequency characteristic can be used as the piezoelectric vibrator of the piezoelectric temperature sensor 10. The transmission / reception antenna 25 is capable of wireless communication and does not require a cord to be wound on the measurement silicon wafer 19.

FIG. 7 shows an outline of the silicon wafer multi-point temperature measurement method 100 for measuring the surface temperature of the measurement silicon wafer 19 by a method different from the silicon wafer multi-point temperature measurement method 100 described with reference to FIGS. It is the whole schematic diagram to explain.
The configuration of the silicon wafer multi-point temperature measuring method 100 shown in FIG. 7 uses one large transmitting / receiving antenna 28 instead of the small transmitting / receiving antenna 25 in the silicon wafer multi-point temperature measuring method 100 described in FIG. 5 has the same configuration as that of FIG. 5 except that the resonance frequency of each piezoelectric temperature sensor is changed.
In FIG. 7 as well, the same parts as those shown in FIG.

The silicon wafer multipoint temperature measuring method 100 shown in FIG. 7 is provided with a single large transmitting / receiving antenna 28 instead of the small transmitting / receiving antenna 25 of the silicon wafer multipoint temperature measuring method 100 described in FIG. A plurality of piezoelectric temperature sensors 10 (Ch1 to Ch6) set so as to have different resonance frequencies are used.
Outside the chamber, a temperature measuring device 20 and an impedance matching unit 21 are installed by being connected by a coaxial cable 22, and a single large transmitting / receiving antenna 28 is also covered with, for example, quartz 26 and connected to the impedance matching unit 21. The coaxial cable 22 is connected outside the chamber, and the single-core heat-resistant cable 27 is connected inside the chamber by a connector 24.

In the silicon wafer multipoint temperature measurement method 100 of FIG. 7, when measuring the temperature of the measurement silicon wafer 19, first, a sweep signal wave that can excite all the channels Ch is transmitted from the temperature measurement device 20. At this time, since the piezoelectric element 11 having a different resonance frequency characteristic is used for the piezoelectric temperature sensor 10 of each channel Ch, the temperature measuring device 20 determines the relationship between each piezoelectric temperature sensor 10 and the resonance frequency characteristic of the piezoelectric element. By storing the combination, it is possible to know from which channel Ch the reverberant vibration wave is based on the frequency characteristics of the received reverberant vibration wave.
Then, when the reverberation vibration wave is obtained, the temperature measurement device 20 calculates the temperature of each point on the surface of the measurement silicon wafer 19 serving as a jig based on the frequency of the reverberation vibration wave.

As described above, in the silicon wafer multipoint temperature measurement method 100 of FIG. 7, the piezoelectric temperature sensor 10 of a plurality of channels Ch having different resonance frequencies and the single large transmitting / receiving antenna 28 are used, so that the measurement silicon wafer 19 is measured. The temperature can be observed. Since the single large transmitting / receiving antenna 28 and the piezoelectric temperature sensor 10 are also wireless, a large number of cords need not be wound on the measurement silicon wafer 19.
7 also transmits the calculation result to the heating control device 90 in the same manner as the temperature measurement device 20 shown in FIGS. 5 and 6, and the heating control device 90 controls the heating means 91. Then, the temperature is adjusted so that the temperature of the measurement silicon wafer 19 in the chamber becomes uniform.

As the single large transmission / reception antenna 28 shown in FIG. 7, for example, an antenna having a rectangular shape may be used, or when installed above the measurement silicon wafer 19, You may use what formed the helical antenna (loop-shaped antenna) so that the surface of this silicon wafer 19 for a measurement might be covered.
Since the single-core heat-resistant cable 27 shown in FIG. 7 is also used in a chamber that is exposed to high temperatures, it is difficult to mount an active element for impedance matching (matching). Therefore, the configuration shown in FIG.
The multi-core heat-resistant cable 23 shown in FIGS. 5 and 6 is a cable in which a plurality of single-core heat-resistant cables 27 are bundled.

As shown in FIG. 8, when the single-core heat-resistant cable 27 is connected to the small transmitting / receiving antenna 25 or the single large transmitting / receiving antenna 28 using a feeder, a twist cord 30 is formed. Copper wires or platinum wires are used for the electric wires so that they can withstand high temperatures.
The characteristic impedance matching unit 29 is an impedance matching unit provided for matching the impedance between the small transmitting / receiving antenna 25 or the single large transmitting / receiving antenna 28 and the twist cord 30. The characteristic impedance matching unit 29 and the twist cord 30 are sealed with heat-resistant quartz 31.
The impedance matching when the frequency is transmitted from the twist cord 30 in the chamber (high temperature portion) to the temperature measuring device 20 outside the chamber (normal temperature portion) is the second impedance matching device 21 installed outside the chamber. Is performed.
Note that the single-core heat-resistant cable 27, the small transmission / reception antenna 25, the large transmission / reception antenna 28, and the like are covered with heat-resistant quartz 26 to oxidize or corrode internal conductors when installed in a heat treatment apparatus to be described later. I try to prevent it.

9 and 10 show examples of the heat treatment apparatus used in the heat processing step shown in FIGS. 5 to 7 for heating the measurement silicon wafer 19 or the silicon wafer to be processed in a high temperature atmosphere. FIG.
FIG. 9 is a cross-sectional view of a single wafer heat treatment apparatus 200 for heat treating silicon wafers for processing one by one. The illustrated single-wafer heat treatment apparatus 200 is, for example, an RTP (Rapid Thermal Process) apparatus, and heats a processing silicon wafer.
When performing heat processing in this RTP apparatus, first, the measurement silicon wafer 19 is placed as a jig on a quartz support base 41 provided in the chamber 40. Then, the measurement silicon wafer 19 is heated by a plurality of heating lamps 42 installed so as to be positioned above and below the measurement silicon wafer 19, and the temperature of each place on the measurement silicon wafer 19 is measured.
Although not shown, it is assumed that the piezoelectric temperature sensor 10 covered with a plurality of silicons is disposed on the surface of the measurement silicon wafer 19 shown in FIG. 9 as described above.

Next, when performing the heating process in this RTP apparatus, the temperature at which the measurement silicon wafer 19 is heated when the measurement silicon wafer 19 is removed and the process silicon wafer is placed on the support base 41 and mounted as a jig. Based on the rising data, heat processing is performed so as to reach a predetermined temperature.
When heat-treating a silicon wafer for processing, the openable / closable door 43 is closed, and a gas such as nitrogen or argon used in the heat processing step is injected into the chamber 40 from the gas inlet 44. The gas injected into the chamber 40 is exhausted from the gas outlet 45.
In FIG. 9, temperature information is detected in this case by using a small transmitting / receiving antenna 25 covered with heat-resistant quartz 26 between the chamber 40 and the plurality of heating lamps 42 above the chamber 40. This is done by installing the small transmitting / receiving antenna 25 on ten concentric axes.
Although the illustrated quartz 26 is covered with a small transmitting / receiving antenna 25, the illustration is omitted.
In this RTP apparatus, a reflector 46 is provided so as to surround the heating lamp 42, the chamber 40, and the like.

The RTP apparatus shown in FIG. 9 has a feature that the temperature can be raised and lowered at high speed. In addition, since this RTP apparatus has a space for installing the small transmitting / receiving antenna 25 covered with quartz 26 between the chamber 40 and the heating lamp 42, the silicon wafer multipoint temperature measuring method 100 described with reference to FIGS. It is suitable when performing heat processing.
In the description of FIG. 9, it has been described that the quartz 26 covers the small transmitting / receiving antenna 25 (not shown). However, when the silicon wafer multipoint temperature measuring method 100 of FIG. This is a single large transmission / reception antenna 28.

In addition, when actually performing heat processing using an RTP apparatus, a large amount of silicon wafers for processing may be heat processed per day.
At that time, instead of observing the surface temperature and controlling the heating temperature every time one wafer is heated, for example, the RTP apparatus is operated and the silicon wafer 19 for measurement mounted as a jig first is operated. By using the temperature rise data and controlling the heating temperature of the processing silicon wafer mounted thereafter with the temperature setting data obtained at this time, the processing silicon wafer can be efficiently heated. I can do it.

FIG. 10 shows a cross-sectional view of a batch-type heat treatment apparatus 300 used when heat-treating a plurality of processing silicon wafers at once.
The illustrated batch type heat treatment apparatus 300 is, for example, a vertical furnace, and when a processing silicon wafer is heated in this vertical furnace, first, for example, the processing silicon wafer is illustrated inside the quartz boat 50. Set to. A plurality of (for example, about 100) silicon wafers 19 can be set in the quartz boat 50. In practice, a number of processing silicon wafers equal to or more than the number shown in FIG. Can do.

  Although not shown in the figure, among the processing silicon wafers shown in FIG. 10 as described above, a temperature measurement silicon wafer 19 serving as a jig is arranged every predetermined number of wafers, and the surface thereof is disposed on the surface. The piezoelectric temperature sensors 10 each covered with a silicon cover 17 are arranged. A plurality of piezoelectric temperature sensors 10 are also arranged on the measurement silicon wafer 19 arranged at a predetermined interval, and used for temperature control when a heating process is performed in a vertical furnace described later.

In FIG. 10, a small transmitting / receiving antenna 25 covered with quartz 26 so as to surround the outside of the quartz boat 50 is installed in the vicinity of the measurement silicon wafer 19 on which the piezoelectric temperature sensor 10 is arranged. At this time, each small transmitting / receiving antenna 25 may be disposed at a position where signals can be transmitted to and received from the piezoelectric temperature sensor 10.
Further, the illustrated vertical furnace is provided with a quartz reaction tube 51 so as to surround the quartz board 50 and the small transmitting / receiving antenna 25 installed outside thereof. A gas such as nitrogen or argon used in the heat processing step is injected into the quartz reaction tube 51 from the gas inlet 52, and this gas is discharged from the gas outlet 53.
A soaking tube 54 is provided outside the quartz reaction tube 51, and a plurality of heating lamps 55 are provided outside the soaking tube 54. The heating lamp 55 is controlled to be heated based on temperature rise data detected by the measurement silicon wafer 19 mounted as a jig, so that the quartz boat 50 in the quartz reaction tube 51 has a desired temperature. The processing silicon wafer to be set is heated.

As described above, in the case of the vertical furnace shown in FIG. 10, a plurality of (for example, about 100) processing silicon wafers can be heated at a time, but at this time, the surface temperature of the processing silicon wafer is reduced. It is necessary to ensure that there is no difference in the position where the is set in the quartz boat 50.
Therefore, by adjusting the surface temperature of the measurement silicon wafer 19 set at predetermined intervals, the heating temperature is adjusted so that the surface temperature of the processing silicon wafer set on the quartz board 50 is uniform. To do.
In FIG. 10, the piezoelectric temperature sensor 10 is embedded in the measurement silicon wafer 19 installed in the upper, interrupted, and lower stages of the quartz board 50. However, if measurement data can be obtained so that the temperature adjustment operation can be performed so that the surface temperature of all the processing silicon wafers set in the quartz boat 50 is uniformly heated, the piezoelectric data is not located at the position shown in the figure. The temperature sensor 10 may be installed.

  Further, when heat processing is performed in the above-described vertical furnace, a plurality of processing silicon wafers are set in a quartz boat 50 and heat processing is performed as shown in the drawing, and a small space is formed above and below the processing silicon wafer. It is difficult to install the transmission / reception antenna 25. 6 is used in the heating process in the case of the silicon wafer multipoint temperature measurement method 100 of FIG. 6 in which signals are transmitted to and received from the piezoelectric temperature sensor 10 by installing the small transmission / reception antenna 25 on the side of the measurement silicon wafer 19. I can do it.

FIG. 11 (a) shows an electrical equivalent circuit in the vicinity of the common point of the crystal resonator when the piezoelectric resonator of the crystal piece is used as the temperature sensor in the present invention.
L shown in the figure is the inductance of the externally attached antenna described above, and the crystal resonator is shown as a parallel capacitor Co, a series capacitor C1, a series inductance L1, and a series resistor R1. In this equivalent circuit, generally, a lower series resonance point fr where the impedance value is minimum and a half (parallel) resonance point fa appear at a high frequency where the impedance value is maximum.
FIG. 11B is an enlarged view of the impedance change characteristic in the vicinity of the resonance point of the piezoelectric vibrator. The fr point is a series resonance point, the fa point is a parallel resonance point, and the crystal vibrator has these resonances. Inductive reactance is shown in the interval of the frequency difference Δf of points.

FIG. 12 is a diagram showing the relationship between the resonance frequency of the temperature sensor, that is, the frequency of the reverberation vibration wave transmitted from the piezoelectric vibrator after excitation, and the temperature.
FIG. 12A is a diagram showing the relationship between the resonance frequency of the reverberation vibration wave and the temperature within a certain temperature range when a crystal piece is used as the piezoelectric element of the piezoelectric vibrator. As shown in the figure, when a piezoelectric vibrator using a crystal receives the same resonance frequency as the crystal or an approximate resonance frequency, the resonance frequency of the reverberation vibration wave transmitted tends to increase as the temperature increases. be able to.
FIG. 12B is a diagram showing the relationship between the resonance frequency of the reverberation vibration wave and the temperature when the langasite is used as the piezoelectric element of the piezoelectric vibrator. When the Langasite piezoelectric vibrator receives the same resonance frequency as the quartz crystal or an approximate resonance frequency, the resonance frequency of the reverberation vibration wave transmitted can be made lower as the temperature becomes lower.

In general, the resonance frequency f and the temperature T of the piezoelectric vibrator are indirect changes. For example, the frequency change rate is calculated by the following polynomial.

Δf / f = A (T-To) + B (T-To) ² + C (T-To) ³ ... + n (T-To) ⁿ

In this polynomial, the coefficients of A, B, C... N corresponding to the piezoelectric elements having different resonance frequencies are obtained in advance by calibration or the like, and the temperature measuring device is used as the coefficient corresponding to each piezoelectric element. It is stored in 20 storage units. Then, a temperature (T-To) obtained by subtracting the reference temperature To from the surface temperature of the measurement silicon wafer 19 and an expected arbitrary temperature T is obtained, and Δf / f which is a frequency change rate is obtained. At this time, (T-To), ( T-To) 2, is the order of n in ^{(T-To) 3 ··· (} T-To) n, is calculated as n = 9 to 13 following, the approximation error A change rate of a small frequency can be calculated.

Next, detection of the reverberation vibration wave of the piezoelectric vibrator will be described with reference to FIG.
The temperature measuring device 20 transmits a transmission signal A that is a resonance frequency signal of a predetermined band in the sweep signal wave to an arbitrary channel Ch or all channels Ch. The transmission signal A transmitted from the temperature measuring device 20 is transmitted to an arbitrary channel Ch or all channels Ch via the small transmitting / receiving antenna 25 or the single large transmitting / receiving antenna 28. This transmission signal A is transmitted from the temperature measurement device 20 during the period t0, and the temperature measurement device 20 transmits the piezoelectric temperature sensor during the period t1 of the reception period B after the transmission period of the transmission signal A, the timing when the period t0 ends. Wait to detect reverberation signal C from 10.
If the frequency of the transmission signal is at or near the resonance frequency of the temperature sensor, a reverberation vibration wave is transmitted from the piezoelectric temperature sensor.
Then, when the temperature measuring device 20 detects the reverberation vibration (reception signal) C in the reception period B, it immediately outputs the echo detection signal D.
Then, a measurement pulse E is generated after a period t3 based on the echo detection signal D, and the frequency of the reverberation vibration wave in the period of the measurement pulse E is counted.
The measurement value in the measurement timing F period is calculated in the calculation period (G) and converted into temperature information.

As shown in the figure, during the same period as the period t2 of the measurement pulse E, the measurement timing signal F measures only the alternating signal of the reverberation signal C (only the reverberation frequency). Then, the calculation G is performed at the timing when the period t2 during which the measurement pulse E is on ends. In this calculation G, the temperature is calculated based on the measured reverberation signal, and the reception period B ends at the timing when the period t4 during which the calculation G is performed ends.
When the echo detection signal D does not detect the reverberation signal C from the piezoelectric temperature sensor 10 during the reception period B, the period t1 of the reception period B ends at the timing when the period t3 of the echo detection signal D ends. Then, the frequency of the next stage in the sweep signal wave is transmitted to an arbitrary channel Ch or all channels Ch.

FIG. 14 is a frequency change diagram of the sweep signal wave transmitted from one temperature measurement device 20 when performing temperature measurement in the silicon wafer multipoint temperature measurement method 100 of FIGS. 5 and 6, and each channel Ch. It shows that sweeping is performed with the frequency changing step by step.
The sweep signal wave of each channel shown in the figure is first transmitted to channel 1 while starting from an arbitrary frequency band and stepping up stepwise. And the reverberation vibration wave from the piezoelectric temperature sensor 10 is waited at the reception timing in the channel Ch1 shown in the figure. If a reverberation vibration wave can be received during this reception period, the channel is switched to the next channel Ch2 and a sweep signal wave is transmitted. Similarly, the reverberation vibration is detected in the channel Ch2, and the reverberation vibrations of all the channels are hereinafter referred to. Temperature information of each point on the measurement silicon wafer 19 is acquired from the wave detection.
In FIG. 14, the period before the sweep signal wave is transmitted from the temperature measurement device 20 to each channel Ch is the time for measuring and calculating the temperature based on the received reverberation vibration wave.

In FIG. 14, the frequency change of the sweep signal wave in the silicon wafer multipoint temperature measuring method 100 of FIGS. 5 and 6 has been described.
Further, in the silicon wafer multipoint temperature measuring method 100 of FIG. 7 in which all channels Ch are swept by a single large transmitting / receiving antenna 28, the temperature measuring device 20 sequentially reverberates vibration from all piezoelectric temperature sensors having different resonance frequencies. It is necessary to continue to transmit the sweep signal wave with a wider sweep width while gradually changing the frequency so that the wave can be received. Disappears.

FIG. 15 shows a method of transmitting the excitation frequency signal from the small transmitting / receiving antenna 25 or the single large transmitting / receiving antenna 28 in the silicon wafer multipoint temperature measuring method 100 of FIGS. It is the figure which showed the block diagram of the temperature measuring apparatus 20 used in order to measure. The temperature measuring device 20 is configured to be totally controlled by a control unit 81 formed of, for example, a microcomputer.
A signal output unit 70 shown in the figure is a signal source that outputs a reference clock signal based on the control of the control unit 81, and a counter 71 is a counter circuit that measures the clock signal and is reset with a predetermined calculation value. The D / A converter 72 is a converter that converts an input signal from a digital signal to an analog signal based on the value counted by the counter 71 under the control of the control unit 81. The VOC 73 is a voltage variable oscillator whose frequency changes according to the output signal level of the D / A converter 72.

The transmission unit 74 includes a frequency converter and a high-frequency amplifier that converts a signal (stepped sweep) output from the VCO 73 into a predetermined frequency based on the control of the control unit 81, and powers up. SW (switch circuit) The signal from the transmission unit 74 is transmitted to the small transmission / reception antenna 25 or the single large transmission / reception antenna 28 via 75.
Further, the reverberation vibration wave received by the small transmission / reception antenna 25 or the single large transmission / reception antenna 28 is switched by the SW 75 after the reception period (for example, the end of the transmission period t0) and input to the reception unit 76. And based on the control of the control unit 81.
And the receiving part 76 amplifies the input signal (reverberation wave) from the outside effectively. The detection unit 77 is a detection circuit that detects an input signal and detects the presence or absence of a reverberation wave.

  The RAM 79 is a RAM table in which, for example, data incremented by the calculation output of the counter 71 is held, and the count data is read when a reverberation wave from the detection unit 77 is detected. Then, the data read from the RAM 79 is calculated in the control unit 81 to obtain temperature information at each point, and the temperature of each part of the measurement silicon wafer 19 is displayed on the display unit 80 as necessary. .

FIG. 16 shows a block diagram of another type of temperature measuring apparatus 20 used in the silicon wafer multipoint temperature measuring method 100 of FIGS.
The temperature measuring device 20 shown in FIG. 16 transmits an excitation frequency signal from the small transmitting / receiving antenna 25 or the single large transmitting / receiving antenna 28 as well as the temperature measuring device 20 shown in FIG. , Used to measure its resonant frequency. Also, in the temperature measuring apparatus 20 shown in FIG. 16, the entire control is performed by a control unit 81 formed of, for example, a microcomputer.

Also in FIG. 16, the signal output unit 70 is a signal source that outputs a reference clock signal based on the control of the control unit 81, and the counter 71a measures the reference clock signal from the signal output unit 70 to perform a predetermined calculation. It is a counter circuit that is reset with a value. The D / A converter 72 is a converter that converts an input signal from a digital signal to an analog signal based on the value calculated by the counter 71 a based on the control of the control unit 81. The VCO 73 is a sweep-type variable voltage transmitter whose frequency changes according to the input signal level, that is, the count value of the counter 71a.
The transmission unit 74 converts the sweep signal wave output from the VCO 73 into a predetermined frequency and powers up based on the control of the control unit 81. It transmits to small transmission / reception antenna 25 or single large transmission / reception antenna 28 via SW75.

A signal from the small transmission / reception antenna 25 or the single large transmission / reception antenna 28 is input to the reception unit 76 via the switch circuit 75 based on the control of the control unit 81. The input external signal (reverberation wave) is detected by the detection unit 77 and supplied to a detection circuit that detects the presence or absence of the reverberation wave.
In this embodiment, the measurement pulse generator 78 is driven by the output of the detector 77 to generate a pulse signal for measurement. Then, the counter 71b to which the output of the receiving unit 76, that is, the reverberation wave is input, is controlled by this measurement pulse signal, the frequency of the reverberation wave is directly measured by the counter 71b, and the measured value is obtained. It is stored in the RAM 79.
Data stored in the RAM 79 is converted into temperature data by the control unit 81, and the data is displayed on the display unit 80 and the like, and the temperature data is output as the temperature control data of the heating means described above. It is.

FIG. 17 shows the antenna of the piezoelectric temperature sensor 10 with the distance (D) at which signal transmission / reception is good between the antenna 14a of the piezoelectric temperature sensor 10 and the small transmission / reception antenna 25 or the single large transmission / reception antenna 28 as the vertical axis. The horizontal axis represents the inductance of 14a.
As shown in the drawing, the piezoelectric temperature sensor 10 has a maximum distance Dm when the distance between the antenna 14a of the piezoelectric temperature sensor 10 and the small transmission / reception antenna 25 or the single large transmission / reception antenna 28 is good. The inductance value Lm of the antenna 14a is shown.
This inductance value Lm is preferably selected so that the resonance frequency of the inductance value Lm and the parallel capacitance Co of the piezoelectric vibration element approximates the resonance frequency (motional) of the piezoelectric vibrator itself according to experiments.

  Note that the temperature of the measurement silicon wafer 19 measured by the temperature measuring device 20 may be expressed by, for example, voice instead of the display unit 80. Further, it is preferable that temperature information is directly supplied from the temperature measuring apparatus 20 to a heat treatment apparatus that heats the measurement silicon wafer 19 to control the temperature of the heat treatment apparatus.

The piezoelectric temperature sensor 10 of the present invention can be easily wireless when the piezoelectric element 11 is used as a temperature sensor. For example, the piezoelectric temperature sensor 10 can be used as an extremely meaningful sensor in an environment where high temperature control is performed. .
Moreover, since it is small and excellent in heat resistance, it cannot be obtained particularly by wire, and can be suitably used as a jig for temperature control of a heating means used in a silicon wafer processing step, for example.

It is the figure which showed the whole piezoelectric temperature sensor in the 1st Embodiment of this invention. It is the figure which showed the whole piezoelectric temperature sensor in 2nd Embodiment. It is the figure which showed the whole figure of the piezoelectric temperature sensor which is a modification of 2nd Embodiment. It is a figure for demonstrating the installation method to the silicon wafer of a piezoelectric temperature sensor. It is the figure which showed an example of the schematic of the silicon wafer multipoint temperature measuring method. It is the figure which showed an example of the schematic of the silicon wafer multipoint temperature measuring method. It is the figure which showed an example of the schematic of the silicon wafer multipoint temperature measuring method. It is a figure which shows an example of a structure of a single core heat-resistant cable. It is a figure which shows an example of a structure of the single wafer type heat processing apparatus which heats a silicon wafer in a heat processing process. It is a figure which shows an example of a structure of the batch type heat processing apparatus which heats a silicon wafer in a heat processing process. It is the figure which expanded the electrical equivalent circuit near the common point of the piezoelectric vibrator used for a temperature sensor, and the impedance change characteristic near a resonance point. It is the figure which showed the relationship between the frequency transmitted from a piezoelectric vibrator, and temperature. It is the figure which showed the operation | movement principle of the temperature measurement at the time of measuring temperature based on a transmission frequency in a temperature measurement apparatus. It is the figure which showed the change of the frequency transmitted from a temperature measuring apparatus, and the timing which receives the frequency from a piezoelectric vibrator. It is the block diagram which showed an example of the structure of the temperature measurement apparatus. It is the block diagram which showed an example of the structure of the temperature measurement apparatus. It is the figure which showed the relationship between the antenna of a piezoelectric temperature sensor, the distance of a transmission / reception antenna and a large transmission / reception antenna, and the inductance of the antenna of a piezoelectric temperature sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Piezoelectric temperature sensor, 11 Piezoelectric element, 12 Slit, 13 (13a, 13b) Electrode, 14a Antenna, 14b Antenna lead, 15a 1st bridge part, 15b 2nd bridge part, 15c 3rd bridge part, 15d 1st 4 bridges, 16 through holes, 17 silicon covers, 18 recesses, 19 silicon wafers, 200 single wafer heat treatment equipment, 300 batch heat treatment equipment

Claims (9)

A piezoelectric vibration region in which excitation electrodes are arranged on both sides;
An antenna region that is spaced apart from the periphery of the piezoelectric vibration region and is provided with a loop-shaped conductor on its surface;
A heat-resistant and electromagnetic wave-transmitting container portion disposed so as to cover the piezoelectric vibration region and the antenna region,
The piezoelectric temperature, wherein the piezoelectric vibration region and the antenna region are coupled by one or more bridge portions, and the excitation electrode and the loop-shaped conductor are coupled through the bridge portion. Sensor.   The separation of the piezoelectric vibration region and the antenna region, and the bridging portion for connecting them are formed by cutting a single plate-like piezoelectric material. Piezoelectric temperature sensor.   The piezoelectric temperature sensor according to claim 2, wherein the outer periphery of the piezoelectric vibration region and the antenna region is formed in a substantially circular shape.   The piezoelectric temperature sensor according to claim 2, wherein outer circumferences of the piezoelectric vibration region and the antenna region are formed in a square shape.   5. The piezoelectric temperature sensor according to claim 3, wherein the container portion is configured by overlapping two concave lids on a peripheral portion of the antenna region.   6. The piezoelectric temperature sensor according to claim 5, wherein the container portion is made of a heat-resistant silicon material.   The piezoelectric temperature sensor according to claim 6, wherein the piezoelectric vibration region, the antenna region, and the bridging portion are formed of a crystal piece.   The piezoelectric temperature sensor according to claim 6, wherein the piezoelectric vibration region, the antenna region, and the bridging portion are made of langasite.   A silicon wafer temperature measuring jig, wherein a plurality of the piezoelectric temperature sensors according to claim 1 are fixed to the surface of a silicon wafer.

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