JPH06188462A - Temperature control method based on indirect type temperature controller and indirect type temperature control device - Google Patents

Abstract

PURPOSE:To make it possible to control the temperature of an object to be cooled or heated by way of a thermal conducting part so as to attain a target value promptly. CONSTITUTION:A temperature sensor 18 detects the temperature of a cooling plate 14 and enters the detected value into a deviation arithmetic operation section 32 of a control change-over section 21. When the deviation required by the deviation arithmetic operation section 32 exceeds a specified value, it is determined that a semiconductor wafer 16 is delivered to the cooling plate 14 and a change-over switch 24 is set to the side of a quenching control constant memory 27 and the quenching control constant memory 27 is connected to a control arithmetic operation section 30. The control arithmetic operation section 30 transmits a control signal to a drive circuit 19 and load-operates a heating and cooling source 12, thereby quenching the cooling plate 14. When the deviation required by the deviation arithmetic operation section 32 comes to zero, a deliver detection section 22 sets a change-over switch 24 to the side of a stabilization control constant memory 28 and forces the control arithmetic operation section 30 to maintain a control target temperature under safety control.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an indirect type temperature control device for supplying hot or cold heat generated by a heat and cold source for heating and cooling to an object whose temperature is controlled via a heat conductor such as metal. More particularly, the present invention relates to a temperature control method using an indirect type temperature controller for cooling and drying a semiconductor wafer in a semiconductor manufacturing process and an indirect type temperature adjusting device.

[0002]

2. Description of the Related Art The manufacturing process of a semiconductor device is as shown in FIG. 7, and it is intended to fix and dry a chemical solution before and after applying, developing, cleaning, etc. the chemical solution to a semiconductor wafer.
In a process called baking, the semiconductor wafer is temporarily heated to a high temperature. Further, the baked wafer is rapidly cooled to around room temperature by an indirect temperature controller called a cooling plate. The temperature of the semiconductor wafer is controlled with accuracy of ± 0.1 ° K as shown in FIG.

When cooled by an indirect temperature controller,
Since it is often difficult to directly measure the temperature of the semiconductor wafer, the temperature of the cooling plate on which the wafer is placed is detected and used as an index for control. When temperature control is performed, in order to ensure control accuracy, a control constant is set in accordance with a cooling plate system having a large heat capacity, and control is performed to keep the temperature of the cooling plate constant.

[0004]

However, when a control constant is set according to the cooling plate system, the semiconductor wafer has a much smaller heat capacity than the cooling plate, and therefore, when the wafer is placed on the cooling plate. In addition, since the cooling plate has a large heat capacity, the temperature change that appears in the temperature detection unit is small, and there is a time delay in the temperature detected by the temperature detection unit. Becomes longer. Therefore, it takes time to enter the next process, which is a bottleneck in improving the production efficiency.

The present invention has been made in order to solve the above-mentioned drawbacks of the prior art, and is an indirect temperature controller capable of rapidly controlling the temperature of an object to be heated or cooled through a heat conducting portion to a target temperature. It is an object of the present invention to provide a temperature control method and an indirect temperature control device according to the above.

[0006]

In order to achieve the above-mentioned object, a temperature control method using an indirect temperature controller according to the present invention is configured so that hot or cold heat output from a heat / cool source is passed through a heat conducting section. In a temperature control method by an indirect temperature controller that applies to an object and heats or cools the object to a predetermined temperature, when the object is carried into the heat conducting unit, the heat cooling source is predetermined. While outputting hot or cold heat, when the heat conducting section reaches a predetermined temperature,
It is characterized in that hot or cold heat according to the deviation between the temperature of the heat conducting portion and the reference temperature is output to the heat / cool source.
The fact that the object is carried into the heat conducting section can be detected by the temperature change of the heat conducting section.

Further, the indirect temperature control device according to the present invention includes a heat-cooling source for heating or cooling an object, and a heat output from the heat-cooling source interposed between the heat-cooling source and the object. Alternatively, a heat conduction unit that transmits cold heat to the target object, a control calculation unit that controls the amount of warm heat or the amount of cold heat output from the heat cooling source, a temperature detection unit that detects the temperature of the heat conduction unit, and the target object And a carry-in detection unit that detects that the heat-conducting unit has been carried into the heat-conducting unit, and a transient for outputting a predetermined hot or cold heat to the heat-cooling source when the object is carried into the heat-conducting unit. When the transient constant storage unit storing the control constant and the heat conduction unit reach a predetermined temperature, the heat or cold heat corresponding to the deviation between the detected temperature of the temperature detection unit and the reference temperature is set to the heat. Stable with stable control constants for output to the cold source A transient control stored in the transient constant storage unit in the control calculation unit by detecting that the object has been loaded into the heat conduction unit based on a detection signal of the number storage unit and the loading detection unit. While performing control using a constant, based on the temperature detected by the temperature detection unit,
A control switching unit that detects that the heat conduction unit has reached the predetermined temperature and causes the control calculation unit to perform control using the stable control constant stored in the stable constant storage unit,
It is configured to have.

The carry-in detection unit outputs a carry-in detection signal when the deviation between the temperature detected by the temperature detection unit and the reference temperature exceeds a predetermined value when the temperature detected by the detection unit is stable. Can be configured. Further, as the carry-in detection unit, a switch provided in the step of transporting the target object or a non-contact type sensor such as an optical sensor or a capacitance sensor can be used.

[0009]

According to the present invention configured as described above, when an object is carried into the heat conducting section, the heat and cold source is operated at a predetermined output, for example, full load, to rapidly heat or cool the object, Bring the temperature of the object closer to the control target temperature as soon as possible. Then, when the object is rapidly heated or rapidly cooled to approach the target temperature and the temperature of the heat conducting section reaches a predetermined temperature, normal control based on the detected temperature of the heat conducting section (eg proportional-plus-integral-derivative control) Is performed to bring the object to a predetermined temperature.

As described above, since the object is brought into operation at full load to rapidly heat or cool it, the temperature of the object can be brought close to the target value at an early stage. Then, when the temperature of the object is close to the target value, control is performed to stabilize the temperature based on the deviation between the detected temperature of the heat conduction section and the target temperature, so the temperature of the object is stabilized at the target temperature early. be able to.

A dedicated sensor such as an optical sensor or a capacitance sensor may be used to detect that the object has been carried into the heat conducting portion, but it is provided in the carrying path for carrying the object. It may be detected by using a limit switch, and further, the change in the temperature of the heat conducting portion due to the fact that the object is carried into the heat conducting portion may be detected to detect that the subject is carried in. If the carry-in is detected by the temperature change, a special sensor is not required and the apparatus can be simplified.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a temperature control method and an indirect temperature control device by an indirect temperature controller according to the present invention,
Detailed description will be given according to the attached drawings. FIG. 1 is an explanatory diagram of an indirect temperature control device according to a first embodiment of the present invention.

In FIG. 1, the indirect temperature controller 10 is
A heat and cold source 12 that generates hot or cold heat by the Peltier effect, and a cooling plate 1 provided above the heat and cold source 12.
4, and the semiconductor wafer 16 which is an object is placed on the cooling plate 14.
The cooling plate 14 is generally made of a metal having a high thermal conductivity, and transfers hot or cold heat generated by the heat cooling source 12 to the semiconductor wafer 16. A temperature sensor 18, which is a temperature detector, is provided below the cooling plate 14, and the temperature of the cooling plate 14 is detected and input to the controller 20.

The controller 20 has a control switching unit 21, a control constant storage unit 26, and a control calculation unit 30. Then, the control switching unit 21 inputs a deviation calculation unit 32 to which the temperature of the cooling plate 14 detected by the temperature sensor 18 is input, a target temperature setting unit 34 that gives a control target temperature to the deviation calculation unit 32, and a deviation calculation unit 32. On the basis of the output signal of the above, the carry-in detector 22 detects that the semiconductor wafer 16 is carried onto the cooling plate 14, and the changeover switch 24 that is switched by the switch signal of the carry-in detector 22. .

The control constant storage unit 26 includes a quenching control constant memory 27 as a transient constant storage unit and a stabilizing control constant memory 28 as a stable constant storage unit.
The control constants stored in these memories are given to the control calculation unit 30 via the changeover switch unit 24. Then, the control calculation unit 30 outputs a control signal to the drive circuit 19 to control the output of the heat / cold source 12.

The operation of the embodiment constructed as described above is as follows. Target temperature setting unit 34 of controller 20
At, a control target temperature (for example, 300 ° K) for maintaining the cooling plate 14 at a predetermined temperature is set. Then, the controller 20 normally performs step 40 of FIG.
As shown in, stable control is performed to maintain the cooling plate 14 at the control target temperature.

That is, the deviation calculation unit 3 of the control switching unit 21
2 reads the output signal of the temperature sensor 18 in a predetermined cycle, obtains the deviation between the target temperature set in the target temperature setting unit 34 and the detected temperature of the temperature sensor 18, and determines the carry-in detection unit 22 and the control calculation unit 30. To enter. The carry-in detection unit 22 monitors the temperature deviation calculated by the deviation calculation unit 32. When the difference between the temperature of the cooling plate 14 and the target temperature is smaller than a predetermined value δT, the carry-in detection unit 22 sets the changeover switch unit 24 to a stabilization control constant memory. Two
8 side, and the stability control constant memory 28 is set to the control calculation unit 30.
The state of being connected to is held (step 41). And
The control calculation unit 30 uses a predetermined calculation formula based on the control constant for stability control for maintaining the cooling plate 14 at the target temperature from the stability control constant memory 28 and the temperature deviation output by the deviation calculation unit 32. The amount of current supplied to the thermal cooling source 12 is calculated, and a control signal is supplied to the drive circuit 19 to supply the thermal cooling source 12
To maintain the cooling plate 14 at a predetermined temperature.

When the semiconductor wafer 16 is loaded onto the cooling plate 14 after the dehydration bake, for example, the temperature of the semiconductor wafer 16 is cooled by the cooling plate 14 and drops as shown in FIG. On the other hand, the cooling plate 14 absorbs heat from the semiconductor wafer 16 and the temperature T _P rapidly rises. Then, the carry-in detection unit 22 of the controller 20 determines that the semiconductor wafer 16 has been carried into the cooling plate 14 when the temperature deviation of the cooling plate 14 becomes larger than δT from the output signal of the deviation calculation unit 32 (step 41), A switching signal is output to the changeover switch unit 24 to control the rapid cooling control constant memory 27 to the control calculation unit 30.
Connect to.

When a control constant for rapid cooling (transient control constant) is input from the control constant memory 27 for rapid cooling, the control calculation unit 30 stops the stable control that has been performed up to now and rapidly cools the cooling plate 14. Therefore, a control signal for operating the thermal cooling source 12 at full load is given to the drive circuit 19 (step 42). The drive circuit 19 supplies the operation amount mv as shown in FIG. 3 to the thermal cooling source 12 based on the output signal of the control calculation unit 30 to generate a large amount of cold heat in the thermal cooling source 12 to rapidly cool the cooling plate 14. To start.

The cooling plate 14 absorbs heat from the high-temperature semiconductor wafer 16 immediately after the rapid cooling is started by the cold energy output from the thermal cooling source 12, and the temperature continues to rise, but eventually reaches a peak, and thereafter. Falls rapidly. Then, when the temperature of the semiconductor wafer 16 approaches the control target temperature, the temperature of the cooling plate 14 becomes lower than the target temperature set in the target temperature setting unit 34. On the other hand, the carry-in detection unit 22 monitors the temperature deviation obtained by the deviation calculation unit 32 to determine whether or not the rapid cooling of the cooling plate 14 is necessary (step 43). The part 24 is maintained on the side of the quenching control constant memory 27. When the deviation output from the deviation calculation unit 32 becomes zero, the carry-in detection unit 22 determines that rapid cooling is not necessary and outputs a switching signal to the changeover switch unit 24, and the stabilization control constant memory 28 and the control calculation unit 30. And connect. As a result, the processing of the controller 20 returns to step 40, and the control calculation unit 30 starts stable control again.

As described above, in the embodiment, the carry-in detector 22 detects the output signal of the deviation calculator 32 from the cooling plate 1.
Since it is detected that the semiconductor wafer 16 has been loaded onto the wafer 4 and the thermal cooling source 12 is operated at full load to rapidly cool the cooling plate 14, the temperature of the semiconductor wafer 16 can be rapidly lowered. Then, when the temperature of the semiconductor wafer 16 decreases to near the control target temperature, the normal stable control for keeping the temperature constant is performed, so that the semiconductor wafer 16 can be quickly stabilized and kept at the target temperature. The processing start time can be shortened, and the semiconductor device production efficiency can be significantly improved.

In the above embodiment, when the rapid cooling control of the cooling plate 14 is canceled, the temperature deviation of the cooling plate 14 from the control target temperature becomes zero. The timing to shift to control can be appropriately determined by experiments or the like.
In the rapid cooling, the semiconductor wafer 16 is cooled by the cooling plate 1.
It may be carried out only for a predetermined time from the time when it is loaded onto the container 4. Further, in the above embodiment, the case where the semiconductor wafer 16 is detected to be loaded by the magnitude of the temperature deviation obtained by the deviation calculating section 32 has been described, but the temperature detected by the temperature sensor 18 is differentiated, The loading of the semiconductor wafer 16 may be detected based on the gradient of temperature change. Further, in the above embodiment, the semiconductor wafer 1 in the manufacturing process of the semiconductor device
Although the case of cooling 6 has been described, it is needless to say that it can be applied to a process other than the manufacturing process of a semiconductor device, and the same can be applied to the case of heating control.

FIG. 4 shows a second embodiment.
In this embodiment, a quenching control determination unit 50 is provided instead of the carry-in detection unit 22 of the control switching unit 21 in the first embodiment.
Then, the carry-in detection unit of the second embodiment includes the cooling plate 14
It is composed of a light emitting portion 52 which emits light 56 and a light receiving portion 54 which the reflected light enters, which is disposed above the light receiving portion 54. The light receiving portion 54 detects the carry-in of the semiconductor wafer 16 and rapidly cools the detection signal. The input is made to the judgment unit 50. Others are the same as those in the first embodiment.

FIG. 5 shows a flow chart of control according to the second embodiment. Compared with the control flow chart of the first embodiment shown in FIG. 2, step 61 corresponding to step 41 of FIG. 2 is different. ing. Then, in the second embodiment, the light receiving section 54 detects that the semiconductor wafer 16 has been loaded onto the cooling plate 14, and starts rapid cooling. That is, the light emitting unit 52 that constitutes the carry-in detection unit irradiates the upper surface of the cooling plate 14 with the light 56. This light 56 is generated by the cooling plate 1
The light is reflected by the upper surface of No. 4 and enters the light receiving unit 54. And
The light receiving portion 54 is formed on the cooling plate 14 by placing the semiconductor wafer 1 on the cooling plate 14.
When 6 is carried in and the reflectance (reflection intensity) changes, a carry-in detection signal is input to the rapid cooling control determination unit 50. When the carry-in detection signal output from the light receiving unit 54 is input, the rapid cooling control determination unit 50 outputs a switching signal to the changeover switch unit 24 and causes the control calculation unit 30 to perform rapid cooling control. The rest is the same as in the first embodiment. A time chart of control according to the second embodiment is shown in FIG.

In the second embodiment, the light 56
The case where it is detected that the semiconductor wafer 16 is loaded by the change in the reflectance of the cooling plate 1 has been described.
4, the light receiving portion 54 is arranged in the portion where the semiconductor wafer 16 is arranged, and the light emitting portion 52 is arranged above the light receiving portion 54.
The carry-in detection signal may be output when the light incident on is blocked. Further, a capacitance sensor is arranged on the cooling plate 14, and a change in the capacitance of the cooling plate 14 due to the semiconductor wafer 16 being arranged on the cooling plate 14 is detected to detect the carry-in of the semiconductor wafer 16. Alternatively, a television camera may be used. Further, the loading of the semiconductor wafer 16 may be detected by a signal from a limit switch provided in the transfer device for the semiconductor wafer 16.

[0026]

As described above, according to the present invention, when an object is carried into the heat conducting portion, the object is rapidly operated by operating the heat / cooling source at a predetermined output, for example, full load. When heating or cooling is performed to bring the temperature of the object closer to the control target temperature as soon as possible, and when the temperature of the object approaches the target temperature and the temperature of the heat conduction part reaches a predetermined temperature, the temperature detected by the heat conduction part is set. Since the normal control (for example, proportional-plus-integral-derivative control) based on the object is controlled to a predetermined temperature, the temperature of the object can be quickly controlled to the target temperature.

It should be noted that the detection that the object has been carried in is
If the change in the temperature of the heat conducting portion due to the object being carried into the heat conducting portion is detected, it is not necessary to provide a special sensor, and the device can be simplified.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an indirect temperature control device according to a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating the operation of the first embodiment.

FIG. 3 is a time chart of control according to the first embodiment.

FIG. 4 is an explanatory diagram of an indirect temperature control device according to a second embodiment of the present invention.

FIG. 5 is a flowchart illustrating the operation of the second embodiment.

FIG. 6 is a time chart of control according to the second embodiment.

FIG. 7 is a flowchart showing manufacturing steps of a semiconductor device.

[Explanation of symbols]

10 Indirect Temperature Controller 12 Heat Cooling Source 14 Heat Conducting Section (Cooling Plate) 16 Object (Semiconductor Wafer) 18 Temperature Detection Section (Temperature Sensor) 20 Controller 21 Control Switching Section 22 Carrying In Detection Section 27 Transient Constant Storage Section (Rapid Cooling) Control constant memory) 28 Stability constant storage unit (stabilization control constant memory) 30 Control calculation unit 50 Quenching control determination unit 52, 54 Carry-in detection unit (light emitting unit, light receiving unit)

Claims (6)

[Claims] 1. A temperature control method using an indirect temperature controller, wherein hot or cold heat output from a heat-cooling source is applied to an object via a heat conducting section, and the object is heated or cooled to a predetermined temperature. When an object is carried into the heat-conducting portion, the heat-cooling source is caused to output predetermined hot or cold heat, and when the heat-conducting portion reaches a predetermined temperature, the temperature of the heat-conducting portion. A temperature control method using an indirect temperature controller, characterized in that hot or cold heat is output to the heat / cooling source according to the deviation between the reference temperature and the reference temperature. 2. The carrying in of the object to the heat conducting section is
The temperature control method using an indirect temperature controller according to claim 1, wherein the temperature is detected by a temperature change of the heat conducting portion. 3. A heat-cooling source for heating or cooling an object, and a heat-conducting unit interposed between the heat-cooling source and the object for transmitting hot or cold heat output from the heat-cooling source to the object. A control calculation unit that controls the amount of heat or cold output by the heat and cold source, a temperature detector that detects the temperature of the heat transfer unit, and that the object is carried into the heat transfer unit. A carry-in detection unit for detecting, and a transient constant storage unit in which a transient control constant for outputting a predetermined hot or cold heat to the heat / cooling source is stored when the object is carried in the heat conducting unit. When the temperature of the heat conducting unit reaches a predetermined temperature, a stable control constant for causing the heat or cold source to output hot heat or cold heat according to the deviation between the detected temperature of the temperature detecting unit and the reference temperature. Stable constant storage section stored and detection of the carry-in detection section Based on the number, the object is detected to have been carried into the heat conduction section, and the control calculation section is caused to perform control using the transient control constant stored in the transient constant storage section, and Based on the temperature detected by the temperature detecting section, it is detected that the heat conducting section has reached the predetermined temperature, and control using the stable control constant stored in the stable constant storage section in the control calculating section. An indirect temperature control device having a control switching unit for performing the following. 4. The carry-in detection unit receives a carry-in detection signal when the temperature detected by the temperature detection unit is stable and the deviation between the reference temperature and the temperature detected by the temperature detection unit exceeds a predetermined value. Is output. The indirect temperature control device according to claim 3, wherein 5. The indirect temperature control apparatus according to claim 3, wherein the carry-in detection unit is a switch provided in the step of carrying the object. 6. The indirect temperature control device according to claim 3, wherein the carry-in detection unit is an optical sensor or a capacitance sensor.