JPS5894016A - Temperature controller - Google Patents

Abstract

PURPOSE:To attain a precise control of temperatures, by performing only the measurement and display of temperatures during the set waiting time and giving the temperature control with the last temperature information after the lapse of the waiting time so that an object to receive the temperature control reaches the target temperature. CONSTITUTION:A temperature sensor 11 consisting of a surface acoustic wave resonator 12 and an amplifier 13 delivers the oscillating frequency corresponding to the ambient temperature and radiates the frequency into a room after the amplification 14. A receiving part 16 receives the radiated electric wave and then amplifies 24 the signal which received a conversion of frequency to supply it to an AND circuit 25. The reference signal of a frequency that varies at 0.1 C is fed to the circuit 25. The output of the circuit 25 is fed to a counter 27 to be turned into the temperature information. This temperature information is fed to a computer COM28. The COM28 displays 29 the detected temperature and delivers the temperature control signal in response to the data read in from an input data 30. After reading in the target temperature T1, the waiting time t and the detected temperature T2, the COM28 keeps the display of the T2 until the time t which is set in consideration of the heat time constant of an object to receive the temperature control is obtained. The COM28 delivers the control signal proportional to T1-T2=DELTAT when t=0 is satisfied.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention uses a temperature sensor to measure tin temperature. This invention relates to a temperature control device that performs 1lIIIlt.

Technical Background of the Invention Conventionally, this type of temperature control device uses a surface acoustic wave oscillator or a crystal oscillator whose oscillation frequency changes depending on the temperature as a temperature sensor, and detects the temperature by receiving the oscillation frequency at a receiving section. However, there are some devices in which temperature control is performed based on this detection output. In this case, the +Dff1 degree sensor is wireless, which allows the sensor to be set mt
m locations can be translated freely and appropriately, and is particularly effective for detecting the temperature of rotating machinery.

Therefore, polishing machines such as silicon wafers (
Applications to temperature control of polishing machines are conceivable. In other words, since the polishing of silicon wafer 1 is mechanochemical polishing, the polishing speed f and polishing conditions change depending on the process, and there is a problem that constant conditions cannot be obtained. ,
Since the polishing is carried out at a rotational speed of m (60-90 RPM),
There was a problem that it was difficult to detect the temperature If of sea urchin/1- during boiling.

However, since the sensor using a surface acoustic wave oscillator or a 6° crystal oscillator is a wireless sensor as mentioned above,
There is no problem even if the plate is 1916, so it is effective to apply it to a polishing machine.

Problems with the Background Art However, there are the following problems when applied to a borising machine. In other words, since the silicon wafer is polished while being sandwiched between two metal plates,
The temperature of the silicon wafer is indirectly controlled by detecting the temperature of the plate and controlling the temperature to be constant.

However, since this plate is made of metal and has a large volume, it has a large thermal time constant, making it difficult to precisely control the temperature.

Purpose of the Invention The present invention has been made in view of the above points.
The object of the present invention is to provide a temperature control device that takes into account the thermal time constant of an object and can perform precise temperature control.

Summary of the Invention The present invention uses a surface acoustic wave oscillator as a temperature sensor, and uses a temperature control device that wirelessly receives temperature information and performs temperature control only for a set standby time to measure and display the temperature. After the standby time has elapsed, the temperature of the object to be controlled is controlled to the target temperature using the last temperature information, and thereafter only the temperature is measured and displayed until a change appears, and if there is a change, the first standby time is reached. By repeating this process, precise 11 degree control can be achieved taking into account the thermal time constant of the object to be controlled.

Examples of the invention Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of the present invention.

8 in the figure, the ff1 degree sensor 11 is LiNb0. It consists of a surface acoustic wave oscillator composed of a surface acoustic wave resonator 12 made of a substrate and an amplifier 13, and has an oscillation frequency output ('?5.235 MHz at 25°C) according to the S ambient temperature.
, a temperature coefficient of -89PPm/"O) is generated, and this output is radiated into the air from antenna 15 via amplification!14. On the other hand, receiver M16 receives radio waves from antenna b.
is as follows. In other words, the RF amplification filter 18 is connected to the antenna 17 that receives the oscillation output of the sensor 11, and the signal received by the antenna 17 is amplified. A total amount 19 is connected to the output end of this intensifier 18. This mixer #a19 is equipped with a local oscillator, and the output of the amplifier 18 is converted into a stable local S oscillation output (85, 92 MHz).
) to beat down and obtain the IF output. This IF output is amplified by the IF amplifier 21.
A mixer ρ is connected to the output end of the device 21. Continue. This mixture 4
! I22 neglects to connect the local oscillator, and the above amplification 1s
After beating down the output of 21 with a stable local oscillator (IO, 522M) (z) corresponding to IP at 0°C, and amplifying this signal with an amplification unit, 0.1"
An AND circuit 6 performs an AND operation with the output of a reference signal station having a frequency of 660 Hz, which changes at 0, and inputs the result to a frequency counter I.

At this time, the first shift of the frequency input to the counter n is am
It has become that. This temperature information is input into a microcomputer. This detected temperature is LB
The D display device outputs temperature 1jl:, 11 control signals according to the data input from the input data.

2cIJ shows a flowchart of one-time continuation and control signal output method performed by microcomputer 4.

In other words, after initial setting, after reading *a rx Tt, waiting time t, and detection fi degree Ti, detection is performed until the samurai and iso time t, which is determined by taking into account the thermal time constant of the target object, is reached. Temperature Tt (only displays D; when t=0, T;
-T, outputs a control signal proportional to ΔT. After that, the detected temperature rl Tt' is continued again, Tt - T2' = j
Only the temperature is displayed until T' i)s h, q□, and then the temperature is displayed in the above-mentioned point II (l[T.

The above steps are repeated to control the temperature so that ΔT=o.

By doing so, the temperature control of a device having a large thermal time constant can be performed with high accuracy such that rj<(aiflJ pull is small). Further, since the standby time t can be set externally according to the thermal time constant, the temperature can be stably controlled with good arrangement even if the controlled object of the fi device changes.

Figure 3 shows an example of a silicon wafer double-sided boring machine used for temperature control. There is a carrier between the upper and lower plates, which rotate in different directions, and the silicon wafer is placed inside the carrier. By flowing grains, you can do both sides at the same time! Polished. In order to prevent the temperature of the silicon wafer from rising due to frictional heat during this polishing and changing the polishing speed and conditions, a pipe a is provided for flowing cooling water through the upper plate 35 and the lower plate 35, Cooling is in progress. Therefore, in order to control the target temperature at once, a hole is provided in the upper plate, and a surface acoustic wave oscillator (U) shown in Figure 11 is inserted into the upper plate, and the oscillation frequency according to the temperature is set. The output is radiated into the air.The receiving section that receives the radio waves from the antenna okara has a configuration as shown in FIG. By controlling and cooling the upper plate 35 and the lower plate 35, the temperature of the silicon wafer is indirectly kept constant.

Since the control method is as shown in the flowchart shown in Fig. 2, the waiting time t can be set according to the thermal time constant of the plate, and the
IV! It was confirmed that precise temperature control was possible and silicon wafers of constant and good quality could be obtained.

Effects of the Invention As described above, according to the present invention, temperature control according to the thermal time constant of the controlled object is always performed stably and with good variety. Also, elastic li! In the case of surface wave collecting resonators and crystal oscillators, their bodies are generally larger than 1M degree sensors such as thermocouples, so the thermal time constant of the sensor itself is large, and precise axatography is required.
t+- was difficult.

The present invention is not limited to the above-described embodiments, and can be practiced with various modifications without changing the gist.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing an embodiment of the present invention.
Fig. 12 is a flowchart of 11KI# of the microcomputer section used in the same embodiment, and Fig. s3 is a section II diagram showing an example in which the invention is applied to a double-sided polishing machine.・ 11.39...ilf: Sensor 12 , ,
(1... Elastic S! Plane wave resonators 13, 14, 18
, 21 , 24 , : [... amplifier 16...
Receiving section 15, 17.33... antenna 19, 2
2...1 combiner 11...Local oscillator Song...Reference signal δ...AND-path n...Frequency counter n
...Microcomputer 4...LftDft-(9) Phase input data fall...Upper plate A...Lower plate A...Silicon wafer A7...Cooling water pipe A...Carrier torture Private patent attorney Chisuke Kiuchika (and 1 other person)

Claims (1)

[Claims] a temperature detector having an oscillator whose oscillation frequency changes by sensing a temperature change in the temperature-controlled body and transmitting the oscillation output; and a temperature control device that receives the transmission output of the detection II and corresponds to the oscillation frequency. a receiving means for detecting a temperature change of the body; and comparing the temperature difference between the detected temperature detected by the receiving section and the target temperature for a predetermined time according to the thermal time constant of the temperature-controlled body, and detecting the temperature difference after the elapse of the predetermined time. 1. A one-degree control device comprising: a control means for outputting a control signal according to a temperature difference, and controlling the temperature of the temperature-controlled body so as to eliminate a difference between the detected temperature and 4IiIs degrees.