JP3199500B2 - Temperature control method and temperature control device using indirect temperature controller - Google Patents

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 applying hot or cold heat generated by a heat / cool source for heating / cooling to an object whose temperature is to be controlled via a heat conductor such as metal. More particularly, the present invention relates to a temperature control method and a temperature control apparatus using an indirect temperature controller for cooling and drying a semiconductor wafer in a semiconductor manufacturing process.

[0002]

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

When cooling with an indirect temperature controller,
It is often difficult to directly measure the temperature of a semiconductor wafer, and the temperature of a cooling plate on which the wafer is mounted is detected and used as an index for control. When temperature control is performed, control constants are set in accordance with a cooling plate system having a large heat capacity in order to secure control accuracy, and control is performed to keep the temperature of the cooling plate constant.

[0004]

However, when the control constants are set in accordance with the cooling plate system, the semiconductor wafer has a much smaller heat capacity than the cooling plate. In addition, since the cooling plate has a large heat capacity, the temperature change appearing at the temperature detecting section is small, and the temperature detected by the temperature detecting section has a time delay. Becomes longer. For this reason, it takes time to enter the next step, which has been a bottleneck in improving production efficiency.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks of the prior art, and is an indirect type temperature controller capable of rapidly controlling the temperature of an object to be heated or cooled via a heat conducting part to a target temperature. It is an object of the present invention to provide a temperature control method and an indirect-type temperature control device.

[0006]

In order to achieve the above-mentioned object, a temperature control method using an indirect temperature controller according to the present invention provides a method for controlling the heat or cold output from a heat or cold source via a heat conducting section. In the temperature control method by the indirect temperature controller for heating the object to a predetermined temperature or cooling the object to a predetermined temperature, when the object is carried into the heat conducting unit, the heat cooling source is predetermined. With the output of hot or cold heat, when the heat conducting portion reaches a predetermined temperature,
The method is characterized in that hot or cold heat corresponding to the deviation between the temperature of the heat conducting section and the reference temperature is output to the hot / cold source.
The fact that the target object has been carried into the heat conducting unit can be detected by a change in the temperature of the heat conducting unit.

In addition, an indirect temperature controller according to the present invention includes a heat-cooling source for heating or cooling an object, and a heat-cooling source interposed between the heat-cooling source and the object, and output from the heat-cooling source. Or, a heat conduction unit that transmits cold heat to the object, a control operation unit that controls the amount of heat or cold heat output from the thermal cooling source, a temperature detection unit that detects the temperature of the heat conduction unit, and the object And a carry-in detection unit that detects that the heat conduction unit has been carried in, and a transient for causing the heat / cool source to output a predetermined warm or cold heat when the object is carried into the heat conduction unit. A transient constant storage unit in which a control constant is stored, and when the heat conducting unit reaches a predetermined temperature, the heat or cold heat corresponding to a deviation between the detected temperature of the temperature detecting unit and a reference temperature is converted to the heat. Stability with stability control constants for output to the cold source A number storage unit, based on a detection signal of the carry-in detection unit, detecting that the object is carried into the heat conduction unit, and controlling the control operation unit to store the transient control stored in the transient constant storage 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 a stable control constant stored in the stability constant storage unit.
Is provided.

The carry-in detecting section outputs a carry-in detection signal when a difference between the detected temperature of the temperature detecting section and the reference temperature exceeds a predetermined value when the detected temperature of the detecting section is stable. Can be configured. The carry-in detection unit may use a switch provided in the process of transporting the target object, or a non-contact type sensor such as an optical sensor or a capacitance sensor.

[0009]

According to the present invention constructed as described above, when an object is carried into the heat conducting portion, the object is rapidly heated or cooled by operating the heat / cooling source at a predetermined output, for example, full load operation. 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 and approaches the target temperature, and the temperature of the heat conduction unit reaches a predetermined temperature, normal control based on the detected temperature of the heat conduction unit (for example, proportional integral differential control) Is performed to bring the object to a predetermined temperature.

[0010] As described above, when the object is carried in, full-load operation is performed to rapidly heat or cool the object, so that the temperature of the object can be quickly brought close to the target value. 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 conducting section and the target temperature, so that the temperature of the object is quickly stabilized at the target temperature. be able to.

The detection that the object has been carried into the heat conducting section may be performed using a dedicated sensor such as an optical sensor or a capacitance sensor. The detection may be performed using a limit switch, and further, the change in the temperature of the heat conducting unit due to the carrying of the object into the heat conducting unit may be detected to detect the carrying of the object. If the carry-in is detected based on a change in temperature, a special sensor is not required, and the apparatus can be simplified.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a temperature control method and an indirect temperature controller using an indirect temperature controller according to the present invention are described below.
This will be described in detail with reference to the accompanying drawings. FIG. 1 is an explanatory diagram of an indirect temperature controller according to a first embodiment of the present invention.

In FIG. 1, an indirect temperature controller 10 comprises:
A hot / cold source 12 for generating hot or cold heat by the Peltier effect, and a cooling plate 1 provided above the hot / cold source 12
And a semiconductor wafer 16 as 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 the hot or cold heat generated by the heat cooling source 12 to the semiconductor wafer 16. A temperature sensor 18 serving as a temperature detector is provided below the cooling plate 14 so that the temperature of the cooling plate 14 is detected and input to the controller 20.

The controller 20 has a control switching section 21, a control constant storage section 26, and a control calculation section 30. The control switching unit 21 includes 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 for giving a control target temperature to the deviation calculation unit 32, and a deviation calculation unit 32 And a changeover switch unit 24 that is switched by a changeover signal of the carry-in detection unit 22 to detect that the semiconductor wafer 16 has been carried over the cooling plate 14 on the basis of the output signal. .

The control constant storage unit 26 includes a quench control constant memory 27 as a transient constant storage unit and a stabilization control constant memory 28 as a stability constant storage unit.
The control constants stored in these memories are supplied to the control operation unit 30 via the changeover switch unit 24. Then, the control calculation section 30 outputs a control signal to the drive circuit 19 and controls the output of the thermal cooling source 12.

The operation of the embodiment constructed as described above is as follows. Target temperature setting unit 34 of controller 20
, 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 operates at step 40 in FIG.
As shown in (1), stable control for maintaining the cooling plate 14 at the control target temperature is performed.

That is, the deviation calculation unit 3 of the control switching unit 21
2 reads the output signal of the temperature sensor 18 at a predetermined cycle, finds a deviation between the target temperature set in the target temperature setting unit 34 and the temperature detected by the temperature sensor 18, and determines the difference between the carry-in detection unit 22 and the control calculation unit 30. To enter. The carry-in detection unit 22 monitors the temperature deviation obtained by the deviation calculation unit 32, and when the difference between the temperature of the cooling plate 14 and the target temperature is smaller than a predetermined value δT, switches the changeover switch unit 24 to a control constant memory for stabilization. 2
8 and the control constant memory 28 for stabilization is stored in the control
Is kept connected (step 41). And
The control calculation unit 30 calculates a predetermined calculation formula based on a 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 heat-cooling source 12 is calculated, and a control signal is supplied to the drive circuit 19 so that the heat-cooling source 12
To maintain the cooling plate 14 at a predetermined temperature.

When the semiconductor wafer 16 is carried on the cooling plate 14 after, for example, dehydration baking, the temperature of the semiconductor wafer 16 is lowered by being cooled by the cooling plate 14 as shown in FIG. On the other hand, the cooling plate 14, the temperature T _P is rapidly increased by absorbing heat from the semiconductor wafer 16. Then, when the temperature deviation of the cooling plate 14 becomes larger than δT from the output signal of the deviation calculating unit 32, the carry-in detection unit 22 of the controller 20 determines that the semiconductor wafer 16 has been carried into the cooling plate 14 (Step 41). A switching signal is output to the changeover switch unit 24 to store the control constant memory 27 for rapid cooling in the control operation unit 30.
Connect to

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

Immediately after rapid cooling is started by the cold heat output from the thermal cooling source 12, the cooling plate 14 absorbs heat from the high-temperature semiconductor wafer 16 and continues to rise in temperature. Declines 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 cooling plate 14 needs to be rapidly cooled (step 43). The section 24 is maintained on the control constant memory 27 for rapid cooling. When the deviation output from the deviation calculation unit 32 becomes zero, the carry-in detection unit 22 determines that rapid cooling is unnecessary, outputs a switching signal to the changeover switch unit 24, and outputs the stabilization control constant memory 28 and the control calculation unit 30. And connect. Thereby, the process of the controller 20 returns to Step 40, and the control calculation unit 30 starts the stable control again.

As described above, in the embodiment, the carry-in detection unit 22 detects the cooling plate 1 from the output signal of the deviation calculation unit 32.
Since it is detected that the semiconductor wafer 16 has been loaded onto the substrate 4 and the cooling plate 14 is rapidly cooled by operating the thermal cooling source 12 at full load, the temperature of the semiconductor wafer 16 can be rapidly lowered. When the temperature of the semiconductor wafer 16 decreases to near the control target temperature, normal stability control for keeping the temperature constant is performed, so that the semiconductor wafer 16 can be quickly stabilized and maintained at the target temperature. Process start time can be shortened, and semiconductor device production efficiency can be greatly improved.

In the above embodiment, the case where the temperature deviation from the control target temperature of the cooling plate 14 becomes zero when the rapid cooling control of the cooling plate 14 is canceled has been described. The timing for shifting to the control can be appropriately determined by experiments or the like.
In the rapid cooling, the semiconductor wafer 16 is
4 may be performed only for a predetermined time from the time when it is carried onto the upper surface. Further, in the above-described embodiment, the case has been described in which the fact that the semiconductor wafer 16 is carried in is detected based on the magnitude of the temperature deviation obtained by the deviation calculation unit 32. However, 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 the temperature change. In the above embodiment, the semiconductor wafer 1 in the manufacturing process of the semiconductor device is used.
Although the case of cooling 6 has been described, it is needless to say that the present invention can be applied to processes other than the semiconductor device manufacturing process, and the same can be applied to the case of heating control.

FIG. 4 shows a second embodiment.
In the present embodiment, a quenching control determining unit 50 is provided in place of the carry-in detecting 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
And a light receiving unit 54 for emitting light 56 and a light receiving unit 54 to which the reflected light is incident. The light receiving unit 54 detects the carry-in of the semiconductor wafer 16 and controls the quenching of the detection signal. The information is input to the determination unit 50. Others are the same as the first embodiment.

FIG. 5 is a flow chart of the control according to the second embodiment. Compared to the control flow chart of the first embodiment shown in FIG. 2, step 61 corresponding to step 41 of FIG. 2 is different. ing. In the second embodiment, the light receiving unit 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 constituting the carry-in detection unit irradiates the light 56 to the upper surface of the cooling plate 14. This light 56 is applied to the cooling plate 1
The light is reflected by the upper surface of the light-receiving unit 4 and enters the light-receiving unit 54. And
The light receiving unit 54 is provided on the cooling plate 14
When the reflectance (reflection intensity) changes due to the carry-in of 6, the carry-in detection signal is input to the quenching control determination unit 50. When the carry-in detection signal output from the light receiving unit 54 is input, the quenching control determination unit 50 outputs a switching signal to the changeover switch unit 24 to cause the control calculation unit 30 to perform rapid cooling control. The following is the same as in the first embodiment. FIG. 6 shows a time chart of the control according to the second embodiment.

In the second embodiment, the light 56
Of the semiconductor wafer 16 is detected based on the change in reflectance of the cooling plate 1.
The light receiving unit 54 is disposed at a portion where the semiconductor wafer 16 of No. 4 is disposed, and the light emitting unit 52 is disposed thereabove.
May be output when the light incident on the device is interrupted. In addition, a capacitance sensor is disposed on the cooling plate 14, and a change in the capacitance of the cooling plate 14 due to the semiconductor wafer 16 being disposed on the cooling plate 14 is detected to detect the loading of the semiconductor wafer 16. Alternatively, a television camera may be used. Further, the loading of the semiconductor wafer 16 may be detected based on a signal of 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 heat cooling source is operated at a predetermined output, for example, a full load operation, and the object is rapidly cooled. Heating or cooling, bringing 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 conducting section reaches a predetermined temperature, the detected temperature of the heat conducting section becomes Based on normal control (for example, proportional-integral-derivative control) to control the target to a predetermined temperature, the temperature of the target can be quickly controlled to the target temperature.

The detection that the object has been carried in is determined by
If a change in the temperature of the heat conducting unit due to the carrying of the object into the heat conducting unit is detected and performed, there is no need to provide a special sensor, and the apparatus can be simplified.

[Brief description of the drawings]

FIG. 1 is an explanatory view 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 a second embodiment.

FIG. 7 is a flowchart showing a manufacturing process of the semiconductor device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Indirect temperature controller 12 Thermal cooling source 14 Heat conduction part (cooling plate) 16 Object (semiconductor wafer) 18 Temperature detection part (temperature sensor) 20 Controller 21 Control switching part 22 Carry-in detection part 27 Transient constant storage part (Quick cooling) Control stability memory) 28 stability constant storage unit (stability control constant memory) 30 control operation unit 50 rapid cooling control determination unit 52, 54 carry-in detection unit (light-emitting unit, light-receiving unit)

Claims (6)

(57) [Claims] 1. A temperature control method using an indirect-type temperature controller for applying a hot or cold heat output from a thermal cooling source to a target object through a heat conduction unit and heating or cooling the target object to a predetermined temperature. When an object is carried into the heat conducting section, the heat / cold source outputs predetermined hot or cold heat, and when the heat conducting section reaches a predetermined temperature, the temperature of the heat conducting section increases. A hot or cold heat corresponding to a deviation between the temperature and the reference temperature is output to the thermal cooling source. 2. The carrying of the object into the heat conducting section,
The temperature control method using the indirect temperature controller according to claim 1, wherein the temperature is detected based on a temperature change of the heat conduction unit. 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 and transmitting the heat or cold output from the heat-cooling source to the object. A control operation unit that controls the amount of heat or cold output from the heat and cold source, a temperature detection unit that detects the temperature of the heat conduction unit, and that the object is carried into the heat conduction unit. A carry-in detection unit to detect, and a transient constant storage unit storing a transient control constant for causing the thermal cooling source to output a predetermined hot or cold heat when the object is carried into the heat conducting unit. When the heat conduction unit reaches a predetermined temperature, a stability control constant for outputting the heat or cold heat to the heat / cool source according to the difference between the detected temperature of the temperature detection unit and a reference temperature is A stored stable constant storage unit, and detection of the carry-in detection unit Based on the signal, the object is detected to be carried into the heat conduction unit, and the control operation unit performs control using a transient control constant stored in the transient constant storage unit, Based on the temperature detected by the temperature detection unit, the control unit detects that the heat conduction unit has reached the predetermined temperature, and controls the control calculation unit using a stability control constant stored in the stability constant storage unit. An indirect temperature controller having a control switching unit for performing the following. 4. A carry-in detection signal is output when a difference between the temperature detected by the temperature detector and a reference temperature exceeds a predetermined value when the temperature detected by the temperature detector is stable. 4. The indirect temperature controller according to claim 3, wherein 5. The indirect temperature controller according to claim 3, wherein the carry-in detection unit is a switch provided in a process of transporting the object. 6. The indirect temperature controller according to claim 3, wherein the carry-in detection unit is an optical sensor or a capacitance sensor.