JPS60155669A - Device for controlling vacuum atmosphere - Google Patents

Abstract

PURPOSE:To provide a titled device which adjusts easily a vacuum atmosphere and enables simplification of the device by the constitution in which the introducing amt. of a gas is selectively controlled by the deviation between the detected value of the flow rate of the gas to a vacuum vessel or the pressure of the vacuum vessel and respective set values. CONSTITUTION:The flow rate of the gas to be supplied via a flow rate control valve 13 to a vacuum vessel 11 to be evacuated by a vacuum pump (not shown) is detected by a flow rate sensor 21 and is outputted to the 1st comparator circuit 23 where the detected flow rate value and the set value signal from a flow rate setting circuit 25 are compared and the deviation is detected. On the other hand, the detection signal of the pressure in the vessel 11 detected by a vacuum gage 29 is outputted to the 2nd comparator circuit 31 where the pressure detection signal and the pressure set signal from a pressure setting circuit 35 are compared and the deviation is detected. The valve 13 is then operated via a valve actuating member 19 by a selecting switch 27 having contact points 27a, b, c in such a way that the deviation of the flow rate or the pressure is selectively made zero. The inflow rate of the gas to the vacuum vessel 11 is thus adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vacuum atmosphere control device that can control the vacuum atmosphere of a vacuum chamber based on both the flow rate and pressure of gas introduced.

Ar in the vacuum chamber, 02. N2. Adjusting a vacuum atmosphere by introducing a gas such as SiH4 or 5iCQ4 is widely used in sputtering equipment, ion blating equipment, reactive vacuum evaporation equipment, plasma generation equipment, and the like. In such devices, gas is introduced into the vacuum chamber based on the pressure within the vacuum chamber or with a constant gas flow rate, and an automatic pressure regulator (APC) or automatic flow rate regulator <A FC) has been used.

However, depending on the type of thin film to be formed, the type of gas phase reaction, discharge conditions, etc., or considering changes in the amount of exhaust gas in the vacuum chamber due to repeated use, it is difficult to increase the pressure in order to obtain the desired thin film characteristics. It has been found that there are cases where it is appropriate to introduce gas and control the vacuum atmosphere based on the flow rate, and there are cases where it is preferable to introduce the gas and control the vacuum atmosphere based on the flow rate. In order to satisfy this request and enable control of both, it is necessary to install two regulators, an automatic pressure regulator and an automatic flow regulator, in one vacuum chamber. The equipment is complicated because it requires an inlet and a gas flow control valve.
Problems arise in that not only is it expensive, there are many locations where leaks can occur, and maintenance management is also complicated.

The present invention has been made from this point of view, and it is an object of the present invention to provide a vacuum atmosphere control device that can easily adjust the vacuum atmosphere based on either pressure or gas flow rate depending on the purpose of use. .

That is, the vacuum atmosphere control device of the present invention compares the output signal from the flow rate sensor and the set flow rate signal, detects a deviation, outputs the first operation signal, and compares the output signal from the vacuum gauge with the set pressure signal. A comparison circuit that compares the values, detects deviations, and outputs a second operating signal, and a flow rate adjustment valve that adjusts the gas flow rate to the vacuum chamber.

a control mechanism that receives the first or second operating signal and controls the opening degree of the flow rate control valve so that the deviation amount is less than or equal to an allowable amount; It is characterized by having a signal switching mechanism that supplies signals to the control mechanism.

The present invention will be described in more detail below with reference to the accompanying drawings.

FIG. 1 is an explanatory diagram showing an embodiment of the present invention, in which a flow control valve 1 is provided in a vacuum chamber 11 that is evacuated by a vacuum pump.
3 is provided, and by controlling the opening degree of this valve 13, gas is supplied to the vacuum chamber 11 from a line 15 through a line 17 at a desired flow rate.

The flow rate sensor 21, the first comparison circuit 23, and the flow rate setting circuit 25 constitute a flow rate control system.

When the contacts 27a and 27b of the changeover switch 27 are connected to enter the flow rate mode, the voltage set by the potentiometer or the like in the flow rate setting circuit 25 is set by the flow rate setting circuit 2
5, the set flow rate signal is sent to the first comparison circuit 23.

The first comparison circuit 23 compares the flow rate output signal from the flowmeter 21 and the set flow rate signal to detect a deviation, and the first comparison circuit 23 outputs a first operation signal according to the deviation. A valve operating member 19 such as a servo motor is actuated by the operation signal, and the opening degree of the control valve 13 is adjusted so that the amount of deviation between the set flow rate signal and the flow rate output signal is equal to or less than zero.

On the other hand, the vacuum gauge 29, the second comparison circuit 31, and the pressure setting circuit 33 constitute a pressure control system.

When the contacts 27a and 27c of the changeover switch 27 are connected to enter the pressure mode, the voltage is set by a potentiometer or the like in the pressure setting circuit 33.
3, the set pressure signal is sent to the second comparison circuit 31.

The second comparison circuit 31 compares the pressure output signal from the vacuum gauge 29 with the set pressure signal, detects a deviation, and outputs a second operation signal from the second comparison circuit 31 in accordance with the deviation. The valve operating member 19 is actuated by the operation signal, and the opening degree of the flow control valve 13 is adjusted so that the amount of deviation between the set pressure signal and the pressure output signal becomes zero. In this pressure control system, it is preferable to PID control the opening degree of the flow rate control valve.

Further, in the above embodiment, the case where the first and second comparison circuits are used to operate the flow rate control system and the pressure control system, respectively, is explained, but one comparison circuit is used to compare the flow rate output signal and the set flow rate signal. Both the comparison and the comparison with the pressure output signal and the set pressure signal may be performed. FIG. 2 is a block diagram showing this embodiment, except that a comparator circuit 24 is used in place of the first and second comparator circuits in FIG. It is similar to that shown in the figure. Contacts 28 at changeover switches 28 and 30 respectively
When the contact a and the contact 28b are connected, and the contact 30a and the contact 30b are connected, the set flow rate signal from the flow rate setting circuit 25 is transmitted to the comparison circuit 2.
4, this signal is compared with the output signal from the flow rate sensor 21 to detect a deviation, and the comparison circuit 24 outputs a first operation signal, and the valve operating member 19 adjusts the opening degree of the flow rate control valve 13. controlled. On the other hand, when the contacts 28a and 28c and the contacts 30a and 30c of the changeover switches 28 and 30 are connected, the output signal of the vacuum gauge 29 is input to the comparison circuit 24, and this signal and the pressure setting circuit 33 are connected. The set pressure signal is compared with the second operating signal, and the opening degree of the flow rate adjustment valve 13 is controlled.

FIG. 3 is a block diagram showing another embodiment of the present invention using a mass flow controller 35.

The mass flow controller 35 includes the flow rate control valve 13,
It includes a valve actuation member 19, a flow rate sensor 21, and a first comparison circuit 23. When the contacts 32a and 32b of the switch 32 are connected, the set flow rate signal from the flow rate setting circuit 25 is input to the first comparator circuit 23, which detects the deviation from the output signal from the flow rate sensor 21 and compares the set flow rate signal with the output signal from the flow rate sensor 21. 1 is output to the valve operating member, and the opening degree of the flow rate control valve 13 is adjusted so that the amount of deviation becomes zero. On the other hand, when the contacts 32a and 32c of the switch 32 are connected, the output signal from the vacuum gauge 29 and the set pressure signal from the pressure setting circuit 33 are compared in the second comparison circuit 31, and a deviation is detected. A second operation signal is output to the valve actuation member 19 via the second comparison circuit 23 of the mass flow controller 35,
The opening degree of the flow rate control valve 13 is adjusted so that the amount of deviation becomes zero.

As described above, according to the vacuum atmosphere control device of the present invention,
A flow rate control valve that can control the flow rate of gas to the vacuum chamber is provided, and a changeover switch or the like is used to selectively control the flow rate valve based on both a flow rate comparison signal and a pressure comparison signal, thereby achieving one flow rate. A control valve can control the vacuum atmosphere based on flow rate or pressure. Therefore, by simply providing one flow control valve or gas inlet for introducing gas into the vacuum chamber, the vacuum atmosphere can be adjusted based on either pressure or gas inflow rate, simplifying the equipment. It is. Furthermore, the number of locations where leaks may occur is reduced accordingly, and maintenance management of the vacuum equipment becomes easier.

[Brief explanation of the drawing]

FIGS. 1, 2, and 3 are block diagrams showing the configuration of an embodiment of the vacuum atmosphere control device of the present invention. In the figure, 11 is a vacuum chamber, 13 is a flow rate control valve, 19 is a valve operating member, 21 is a flow rate sensor, 23 is a first comparison circuit, 24 is a comparison circuit, 25 is a flow rate setting circuit, 27 is a changeover switch, 29 is a vacuum gauge, 31 is a second comparison circuit, 33
35 is a pressure setting circuit and a mass flow controller. Patent applicant: Shinku Kikai Kogyo Co., Ltd. Representative: Patent attorney: Takuya Ohara Figure 3

Claims (1)

[Claims] Compare the output signal from the flow rate sensor and the set flow rate signal to detect a deviation and output a first operation signal, and compare the output signal from the vacuum gauge and the set pressure signal to detect the deviation. and a comparison circuit that detects and outputs a second operation signal. a flow rate adjustment valve that adjusts the gas flow rate to the vacuum chamber; a control mechanism that receives the first or second operation signal and controls the opening degree of the flow rate control valve so that the deviation amount is equal to or less than an allowable amount; A vacuum atmosphere control device comprising: a signal switching mechanism that selectively supplies the first or second operation signal to the control mechanism.