JPH05299379A - Temperature control device and method thereof - Google Patents

Abstract

PURPOSE:To quicken a refrigerant feed rate to shorten the time to be elapsed before the pressure of a refrigerant reaches a prescribed set value as well as to prevent generation of overshoot. CONSTITUTION:A support stage 7 to support a wafer 9 is provided in a vacuum container 2 of a plasma treating device 1 and a space 7a is formed by a sealing material 8. A high-frequency voltage is applied between the stage 7 and an electrode 6 to produce plasma and the wafer 9 is subjected to processing with this plasma. A temperature control device 15 consists of a refrigerant feed pipe 16, a control valve 17, a refrigerant piping 18, a pressure indicator 20, a control part 22 and a refrigerant discharge pipe 26. The control part 22 compares a pressure detected by the pressure indicator 20 with a pressure corresponding to a previously set temperature to control the amount of opening and shutting of the valve 17. The piping 18 between the valve 17 and the pressure indicator 20 is provided with a leak piping 30 provided with a flow rate limiting valve 31 and a flow path on-off valve 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature adjusting device for processing a silicon wafer or the like in a vacuum by plasma processing.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 3, a plasma processing apparatus 1 equipped with a temperature control device of this type is vacuumed with a space 3 defined by a vacuum chamber 1 surrounded by chamber walls as a processing space. A reaction gas supply port 4 is provided in the upper part of the container 1, and a reaction gas exhaust port 5 is provided in the side part,
Inside, an electrode 6 protruding from the top surface portion and a support base 7 protruding from the bottom surface portion are provided. A seal material 8 that forms a coolant space 7 a between the silicon wafer 9 as an object and the support base 7 is attached to the upper end surface of the support base 7, and a gap portion is provided between the support base 7 and the electrode 6. 3a is formed. A coolant introduction hole 10 for introducing a coolant into the coolant space 7a is provided at the center of the support base 7.
Is an external pipe connection port of the refrigerant introduction hole 10.

The temperature adjusting device 15 includes a refrigerant supply pipe 16 communicating with a refrigerant supply source (not shown), a control valve 17 for controlling the amount of refrigerant supplied from the refrigerant supply source, the control valve 17 and the external pipe connection port 10a. And a pressure gauge 20 installed in the middle of the refrigerant pipe 18 for detecting the supply pressure of the refrigerant, and a pressure detected by the pressure gauge 20 and a pressure corresponding to a preset temperature. And a control unit 22 for controlling the opening / closing amount of the control valve 17, a refrigerant discharge valve 25 for discharging all the refrigerant in the refrigerant pipe 18 to the outside, and a refrigerant discharge pipe 26 communicating with the refrigerant discharge valve 25. Composed of.

The operation of the above configuration will be described below. First, the space 3 in the vacuum container 2 is evacuated from the reaction gas exhaust port 5 by a vacuum pump (not shown), and a predetermined reaction gas is introduced into the vacuum space 3 from the reaction gas supply port 4,
A high frequency voltage is applied between the support 7 and the electrode 6 to generate plasma, and the silicon wafer 9 is processed by this plasma. At this time, the surface of the wafer 9 is usually exposed to plasma and heated. In order to suppress burnout of the wafer 9 due to heating and unnecessary reactions on the wafer surface, a coolant is introduced into the space 7a on the back surface of the wafer 9 to transfer the heat of the wafer 9 to the support base 7
To control the temperature of the wafer 9.

Usually, a gas such as He is used as the refrigerant, and the pressure is controlled in order to keep the amount of heat transfer constant. The pressure control detects the pressure of the gas to the refrigerant introduction hole 10 by the pressure gauge 20 installed in the middle of the refrigerant pipe 18, and compares the pressure signal 21 with the pressure corresponding to the preset temperature in the control unit 22. Control valve 17 according to the pressure difference
A driving signal 23 is sent to the control valve 17 to control the opening / closing amount of the control valve 17 so that the support value of the pressure gauge 20 matches the set value. When the wafer processing is completed, the refrigerant discharge valve 25 is opened, and the refrigerant in the refrigerant pipe 18 is discharged from the refrigerant discharge pipe 26.

[0006]

However, in the above-mentioned conventional temperature adjusting device, when the control valve 17 is opened and the refrigerant is supplied, the refrigerant pressure exceeds the set value set by the control unit 22 as shown in FIG. Since the overshoot is maintained by the shoot, the refrigerant pressure remains above the set value. This overshoot becomes particularly noticeable when the refrigerant supply speed is increased, and therefore the refrigerant supply speed needs to be slowed down, and there is a drawback that it takes time for the refrigerant pressure to reach a predetermined set value.

Therefore, the present invention has been made in view of the above-mentioned conventional drawbacks, and an object of the present invention is to increase the refrigerant supply speed until the refrigerant pressure reaches a predetermined set value. An object of the present invention is to provide a temperature adjusting device and a temperature adjusting method that reduce the time and prevent the occurrence of overshoot.

[0008]

In order to achieve this object, a temperature adjusting apparatus according to the present invention supplies a refrigerant between an object and a support table that supports the object, and supplies the refrigerant with a pressure. A temperature adjusting device that controls the temperature of an object by changing the amount of heat transfer from the object to the support table by variably controlling the refrigerant supply source for supplying a refrigerant, and the refrigerant supply from the refrigerant supply source. A control valve for controlling the amount, a pressure detection means installed between the control valve and the object for detecting the supply pressure of the refrigerant, and a pressure detected by the pressure detection means and a pressure corresponding to the set temperature. In comparison, it comprises a control unit for controlling the opening / closing amount of the control valve, and a leak pipe arranged between the control valve and the pressure detecting means. Further, the temperature adjusting method according to the present invention supplies a refrigerant between an object and a support table that supports the object, and variably controls the supply pressure of the refrigerant to transfer heat from the object to the support table. Is a temperature adjusting method for controlling the temperature of an object by changing the temperature of the object, the refrigerant supply amount from the refrigerant supply source is controlled by the control valve, the pressure of the supplied refrigerant is detected, and the detected pressure and the set temperature are set. The opening / closing amount of the control valve is controlled by comparing with a corresponding pressure, and a part of the supplied refrigerant is discharged to the outside.

[0009]

In the present invention, the overshoot of the refrigerant pressure supplied from the control valve is discharged to the outside from the leak pipe.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a temperature adjusting device and a temperature adjusting method according to the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view of a temperature adjusting device according to the present invention. In the figure, the same components as those of the conventional technique are designated by the same reference numerals, and detailed description thereof will be omitted. A feature of the present invention is that the refrigerant pipe 18 between the control valve 17 and the pressure gauge 20 is provided.
The leak pipe 30 is arranged at the point. That is, the leak pipe 30 is provided with a flow rate restricting valve 31 and a flow path opening / closing valve 32 that guide a part of the refrigerant in the refrigerant pipe 18 to the leak pipe 30, and are connected to the refrigerant discharge pipe 26.

The temperature adjusting device according to the present invention has the above-mentioned structure, and its operation will be described below. First, the control valve 17 is opened to start pressure control, and at the same time, the flow path opening / closing valve 32 is opened. The coolant supplied from the control valve 17 is stored in the back surface space 7 a of the wafer 9 and a part of the coolant is discharged to the outside through the flow passage restriction valve 31 and the flow passage opening / closing valve 32.

That is, as shown in FIG. 2, since the refrigerant pressure for the overshoot is discharged from the leak pipe 30 to the outside, the refrigerant pressure supplied from the refrigerant pipe 18 to the back surface space 7a of the wafer 9 is The overshoot amount is corrected and held at the set value set by the control unit 22.
Moreover, when the refrigerant supply speed from the control valve 17 is increased, the amount of the refrigerant discharged from the leak pipe 30 to the outside increases accordingly, so that the overshoot correction time is almost constant regardless of the refrigerant supply speed. Therefore, it is possible to increase the refrigerant supply speed and shorten the time until the refrigerant pressure reaches the predetermined set value.

[0013]

As described above, according to the present invention, the leak pipe is arranged between the control valve for supplying the refrigerant to the refrigerant pipe and the pressure detecting means to constantly discharge a part of the refrigerant to the outside. Therefore, even if the refrigerant supply amount in the control valve is increased and the pressure is increased at high speed, the overshoot amount is corrected and the refrigerant pressure can be held at the set value. The time required to reach the pressure can be shortened and the set pressure is always maintained.

[Brief description of drawings]

FIG. 1 is a side sectional view of a temperature adjusting device according to the present invention.

FIG. 2 is a state diagram with time of refrigerant pressure by the temperature adjusting device according to the present invention.

FIG. 3 is a side sectional view of a conventional temperature adjusting device.

FIG. 4 is a state diagram of refrigerant pressure with time according to a conventional temperature adjusting device.

[Explanation of symbols]

 18 Refrigerant piping 30 Leak piping 31 Flow rate limiting valve 32 Flow path opening / closing valve

Claims (2)

[Claims] 1. A refrigerant is supplied between an object and a support table that supports the object, and the supply pressure of the refrigerant is variably controlled to change the amount of heat transferred from the object to the support table. In the temperature control device for performing the temperature control of, the refrigerant supply source for supplying the refrigerant, the control valve for controlling the refrigerant supply amount from the refrigerant supply source, the refrigerant installed between the control valve and the object A pressure detecting means for detecting the supply pressure, a control section for controlling the opening / closing amount of the control valve by comparing the pressure detected by the pressure detecting means with the pressure corresponding to the set temperature, the control valve and the pressure detecting means. And a leak pipe disposed between the temperature adjusting device and the leak adjusting device. 2. A refrigerant is supplied between an object and a support table that supports the object, and the supply pressure of the refrigerant is variably controlled to change the amount of heat transferred from the object to the support table. In the temperature adjusting method for controlling the temperature of, the refrigerant supply amount from the refrigerant supply source is controlled by the control valve, the pressure of the supplied refrigerant is detected, and the detected pressure and the pressure corresponding to the set temperature are compared. A temperature adjusting method comprising controlling the opening / closing amount of the control valve and discharging a part of the supplied refrigerant to the outside.