KR20130036266A - Vacuum control system and vacuum control method - Google Patents

Abstract

PURPOSE: A vacuum control system and a vacuum control method are provided to control a gas flow in a vacuum container by controlling a direction of a processing gas. CONSTITUTION: A vacuum container(500) receives a processing gas from a gas supply unit to process an object. A vacuum control valve(100,200) is connected between a vacuum pump(300) and each gas outlet(561,562) arranged in the vacuum container. A pressure measuring unit(631) measures the vacuum pressure of the processing gas supplied to the object. A controller(610) controls the opening of each vacuum control valve according to the measured vacuum pressure. [Reference numerals] (610) Controller; (620) Correction value data storage unit; (AA) Gas(flow rate Q); (pv1) Reference valve opening command value; (Pv2) Valve position command value; (Pva) Offset valve opening command value;

Description

Vacuum control system and vacuum control method {VACUUM CONTROL SYSTEM AND VACUUM CONTROL METHOD}

The present invention relates to a technique for controlling the behavior of a fluid in a vacuum vessel used in a manufacturing process with a vacuum control valve.

In the semiconductor manufacturing process, for example, the wafer W to be processed is placed inside a vacuum vacuum chamber 710 (see FIGS. 20 and 21), such as chemical vapor deposition (CVD), and the wafer W is used. There is a process of exposing the process surface Ws to the process gas (hereinafter, simply referred to as gas). The process gas contains a thin film constituent element and reacts on the process surface Ws to form a film material.

In order to form a uniform film, a more stable and uniform supply of process gas is required for the wafer (W). On the other hand, in the conventional CVD process, evacuation by a vacuum pump is performed while supplying process gas by the structure as shown in FIG. 20, FIG. In this exhaust control, it is generally performed by operating the conductance of an exhaust system using the pendulum valve which moves the pendulum 720 and controls the opening / closing amount.

Japanese Patent Application Publication No. 2009-117444

However, in such a method, when the position of the pendulum 720 moves to adjust the conductance, the center of the opening moves with the movement of the pendulum 720. Such movement of the center of the opening causes a bias in the flows FL1 and FL2 of the gas inside the vacuum chamber 710, and causes a non-uniformity of the gas supply, for example, the generation of a region where the gas supply is stagnant. It was. In addition, the nonuniformity of the supply of gas occurs as the concentration decrease of the thin film constituent element in the vicinity of the exhaust side of the wafer W in the configuration in which the gas is supplied from one side of the wafer W and the gas is exhausted from the other side. Was doing. Such a bias in the supply of gas also causes a bias in the film pressure on the process surface Ws, and the influence has been brought about with the progress of higher precision and higher density of the product as described above.

The present invention has been made to solve at least part of the above-described conventional problems, and an object thereof is to provide a technique for controlling the flow of gas in the interior of a vacuum container.

The means 1 is a vacuum control system which controls the vacuum pressure and flow of the process gas in the vacuum container which receives the supply of process gas from a gas supply part, and performs a process to a process target using a vacuum pump. The vacuum control system measures each vacuum control valve connected between each of the plurality of gas outlets disposed at different positions in the vacuum vessel and the vacuum pump, and the vacuum pressure of the process gas supplied to the process target. And a control device for manipulating the degree of opening of each of the plurality of vacuum control valves in accordance with the measured pressure.

In the means 1, the discharge from each discharge part arranged at a different position in the vacuum container can be manipulated to control the vacuum pressure and the direction of flow of the process gas in the vacuum container. As a result of the setting of the conditions of the semiconductor process, not only the pressure and the flow rate of the process gas, but also the operation of the direction of the flow of the process gas as the third operation parameter can be performed, thereby obtaining a new degree of freedom called the direction of the flow of the process gas. have.

The vacuum pump may be connected to a common vacuum pump from a plurality of vacuum control valves, or may be provided one for each of the plurality of vacuum control valves. The control of the flow of the process gas may be implemented to intentionally manipulate the direction, or may be mounted on the process target surface to realize a uniform flow of process gas from the supply portion of the process gas toward each exhaust portion as follows. .

The means 2 is a means 1, wherein the plurality of gas outlets are arranged at positions in which the process reaction regions in which the processes are executed are fitted inside the vacuum vessel. The pressure measuring unit measures the vacuum pressure of the process reaction region. By doing in this way, the operation amount of the vector of the flow of the gas in a vacuum container by adjustment of each gas outlet can be enlarged, controlling the vacuum pressure in a process reaction area | region. In addition, by setting the uniform exhaust flow rate, it is possible to easily realize the uniform flow of the process gas on the process target surface.

The "position where the process reaction regions are sandwiched" does not need to be arranged in a plane parallel to the plane to be the process object, but may be arranged shifted in the vertical direction. In addition, when the number of gas outlets is odd, the position arrange | positioned at equal intervals or nonuniform interval in the annular position centering on the supply part of a process gas is also included in the "position which pinches process reaction area | region".

And means 3, in means 2, wherein the control device compensates for the difference in conductance from the process reaction region to the respective gas outlets and at least one of the individual differences in each exhaust system including the vacuum pump and the vacuum control valve. The exhaust flow rates of the plurality of vacuum control valves are controlled to be close to each other.

According to the means 3, even if there is a difference in conductance from the process reaction region to each exhaust portion or individual differences in each exhaust system, a uniform flow of process gas can be realized from the supply portion of the process gas to the respective exhaust portions on the process target surface. . In addition, design restrictions due to conductance can be relaxed, and the degree of freedom in designing the interior of the vacuum container can be increased.

Means 4 are means of means 2, wherein the control device compensates for the difference in conductance from the process reaction region to the respective gas outlets and at least one of the individual differences in each exhaust system including the vacuum pump and the vacuum control valve. And control so that the execution exhaust velocity in the process reaction region of the plurality of vacuum control valves is close to each other.

According to the means 4, it is possible to easily control the vacuum pressure and the flow of the gas by using the execution exhaust speed that can be directly calculated based on the supply amount of the gas that can be measured and the vacuum pressure of the process gas.

The means 5 is a means 3 or 4, wherein the control device uses an offset value storage for storing an offset value for compensating at least one of the difference and the individual difference, and the offset value read from the offset value storage. And a target value setting section for setting target values for controlling the opening degree of the plurality of vacuum control valves. By doing in this way, control of the opening degree of several vacuum control valve can be implement | achieved easily.

The means 6 is a means 5, wherein the plurality of vacuum control valve has a blocking function to block the flow of gas. The control device has a function of generating the offset value based on the respective characteristic data of the plurality of vacuum control valves, and storing the generated offset value in the offset value storage unit. The characteristic data is data for operating one of the plurality of vacuum control valves and setting the target value obtained in a state in which the other one of the plurality of vacuum control valves is shut off.

According to the means 6, since characteristic data of a plurality of vacuum control valves can be obtained separately, simple mounting is possible by using the linearity of the gas flow. The data for setting the target value has a wide meaning and is not necessarily limited to data indicating the target value itself. For example, data indicating the opening degree of the vacuum control valve (measured value of the opening degree) may be used.

The means 7 is a means 5 or 6, in which the control device outputs a common opening degree command value, which is a common command value for operating each opening degree of the plurality of vacuum control valves, in accordance with the measured vacuum pressure. And a plurality of subordinate control units provided for each of the vacuum control valves to control the opening degrees of the plurality of vacuum control valves in accordance with the main control unit and the common opening degree command value. Each said subordinate control part acquires the actual value of the opening degree of each said vacuum control valve, and controls the opening degree of each said vacuum control valve according to each said actual value, the said common opening degree command value, and the said offset value.

According to the means 7, since it is controlled based on the actual value of the opening degree of each vacuum control valve, the linearity of the relationship between a control input and an opening degree can be ensured. By using this linearity, this structure can control by a common control rule by a main-control part even if the opening degree range of each vacuum control valve shifts with each other by an offset value. In other words, the present configuration secures the linearity of the opening degree and the control input by the actual measurement of the opening degree, thereby realizing the suppression of the characteristic change of the vacuum control valve even when the opening degree range is shifted from each other.

The means 8 is a vacuum control system of any one of the means 1 to 7, wherein the plurality of vacuum control valves are vacuum control valves for controlling the vacuum pressure in the vacuum vessel by manipulating the valve opening with a working fluid, the vacuum A control valve body having a flow path for connecting the vessel and the vacuum pump, a valve seat formed in the flow path, an operation of the valve opening degree by adjusting a lift amount that is a distance from the valve seat, and the valve seat A valve body for blocking the flow path by contact with a furnace, an operating portion having a piston, a rod coupling the valve body and the piston, a cylinder connected to the control valve body to accommodate the piston, and A pressing portion for urging the operating portion in a direction in which the lift amount decreases, and a gap between the outer circumferential surface of the piston and the inner circumferential surface of the cylinder; , It provided with a bellows for sealing diaphragm while tracking the motion of the piston. The operating part and the cylinder are sealed by the bellows and have a cylindrical shape surrounding the rod, and are loaded in a direction in which the lift amount is increased with respect to the piston in accordance with the working pressure of the working fluid. A valve opening degree operating chamber for generating a pressure and a shutoff load generation chamber for sharing a central axis with the valve opening degree operating chamber and generating a load in a direction in which the lift amount is reduced with respect to the operating portion in accordance with the supply of the working fluid; Equipped.

In the means 8, the control is performed by a vacuum control valve which closes the gap between the outer circumferential surface of the piston and the inner circumferential surface of the cylinder with a film-like elastic body that seals while following the operation of the piston. Since the vacuum control valve of such a structure has low hysteresis characteristic, the control performance of a vacuum control system can be improved significantly.

The means 9 is a means 8, wherein the cylinder has a head cover having a sliding convex portion accommodated in the breaking load generating chamber. The vacuum control valve has a sealing surface for sealing between the breaking load generating chamber and the sliding convex portion, and includes a sealing portion for increasing the surface pressure of the sealing surface in accordance with the supply of the working fluid to the breaking load generating chamber.

As for the vacuum control valve of the means 9, the sealing part in which the surface pressure of a sealing surface becomes high according to supply of the working fluid to a breaking load generation chamber is used for the breaking load generation chamber. Thereby, at the time of operation | movement of a valve opening degree, ie, non-blocking, it is possible to suppress the surface pressure of the sealing surface of the interruption load generation chamber, and to move with a low friction sliding movement. As a result, for example, operation of the valve opening degree in low hysteresis can be realized with a simple structure, even without a bellows ram.

The means 10 is a means 9, wherein the sliding convex portion shares a central axis with the valve opening degree operating chamber, and has a cylindrical shape having an outer diameter smaller than the inner diameter of the valve opening degree operating chamber, and the operating portion is sliding. In the space surrounded by the inner peripheral surface of the convex portion having a guide portion extending in the direction of the operation,

The vacuum control valve is disposed between the guide portion and the sliding convex portion to enable sliding in the direction of the operation, and the position in the direction perpendicular to the direction of the operation of the guide portion and the sliding convex portion. Bearings constraining the relationship to each other.

Since the vacuum control valve of the means 10 has a guide portion extending in the direction of motion in a space surrounded by the inner circumferential surface of the cylindrical sliding convex portion, the sliding convex portion is located closer to the bearing than the sliding surface of the bellows ram. The sliding surface is arranged. Thereby, the precision of the clearance gap of the sliding surface between the interruption load generation chamber and the sliding convex part which has more stringent precision than a bellows ram can be improved easily.

The means 11 is any one of means 8 to 10, wherein the breaking load generating chamber is formed inside the rod.

The means 12 is any one of the means 8-11, The said control apparatus is a pressure sensor which measures the vacuum pressure in the said vacuum container, the working fluid supply part for supplying a working fluid, and the working fluid for exhausting the working fluid. A control unit which is connected to an exhaust unit and operates a pneumatic circuit for supplying the working fluid to the vacuum control valve and a working fluid supplied from the pneumatic circuit to the vacuum control valve to control the vacuum pressure in the vacuum container. do.

The means 13 is a means 12, wherein the control device connects a flow path between the valve opening degree operation chamber and the working fluid exhaust unit in response to receiving a vacuum pump stop signal including information indicating the stop of the vacuum pump, The flow path between the interruption load generating chamber and the working fluid supply portion is connected.

In the vacuum control system of the means 13, an operation mode in which the breaking load is applied in response to the reception of the vacuum pump stop signal is applied, so that the shut-off state can be secured even if the pressure on the vacuum pump side increases due to the unpredictable stop of the vacuum pump. Have In addition, "receiving a vacuum pump stop signal" has a broad meaning including, for example, checking the status of an internal contact on the side of the vacuum pump indicating the operating state of the vacuum pump, or not reaching a steady signal of the vacuum pump. have.

The means 14 is a means 12 or 13, wherein the pneumatic circuit comprises a first electromagnetic valve for connecting a flow path between the valve opening operation chamber and the working fluid exhaust in a non-energized state; And a second electromagnetic valve for connecting a flow path between the working fluid supplies.

The vacuum control system of the means 14 comprises a first electromagnetic valve connecting a flow path between the valve opening degree operation chamber and the working fluid exhaust part in a non-energized state, and a flow path between the shutoff load generating chamber and the working fluid supply part in a non-energized state. Since it has a 2nd electromagnetic valve which connects to it, it will always be in an emergency interruption state at the time of a power supply off or a power failure. As a result, it is possible to easily realize a system design in consideration of securing safety during emergency stop or power failure.

The means 15 is a vacuum control method of controlling the vacuum pressure and the flow of the process gas in the vacuum container which receives the supply of the process gas from the gas supply part and executes the process to the process object. This vacuum control method includes the steps of preparing each vacuum control valve connected between each of a plurality of gas outlets disposed at different positions in the vacuum container and the vacuum pump, and the process gas supplied to the process target. And a pressure measuring step of measuring a vacuum pressure, and a control step of manipulating respective opening degrees of the plurality of vacuum control valves in accordance with the measured vacuum pressure.

Moreover, it is not limited to the manufacturing apparatus of a semiconductor, It is applicable to the manufacturing method of a semiconductor, and can also be used for the process apparatus which flows gas in a vacuum container.

According to the first means, not only the pressure and the flow rate of the process gas but also the operation of the direction of the process gas as the third operation parameter can be provided, thereby providing a new degree of freedom, which is the direction of flow, for setting the conditions of the semiconductor process.

1 is a cross-sectional view showing a configuration of a vacuum control system 10 of a first embodiment.
2 is a plan view of the vacuum control system 10.
3 is a control block diagram of a vacuum control system 10.
4 is a flowchart showing the operation contents of the control system of the vacuum control system 10.
5 is a flowchart showing the contents of an offset valve opening degree command value acquisition process;
6 is an explanatory diagram showing how the vacuum control valve 100 operates by a single body.
7 is an explanatory diagram showing a calculation formula used for calculating the effective exhaust velocity.
8 is a cross-sectional view illustrating a configuration of a vacuum control system 10a of a modification.
FIG. 9 is a cross-sectional view showing a configuration of a vacuum control valve 30 at the time of non-energization (valve full closing) in the second embodiment. FIG.
10 is an enlarged cross-sectional view showing the configuration of the rod cover 81 of the vacuum control valve 30 at the time of non-energization.
11 is a cross-sectional view illustrating a configuration of a vacuum control valve 30 at the time of valve expansion.
12 is a cross-sectional view showing an operating state at the time of controlling the vacuum pressure of the vacuum control valve 30.
13 is an enlarged cross sectional view showing a friction surface between the packing 70 and the inner circumferential surface 63;
14 is a schematic diagram illustrating a sealing state by showing a mounting state of the packing 70.
15 is a schematic diagram illustrating a sealing principle by showing a state at the time of non-pressurization of the breaking load generating chamber 39.
FIG. 16: is a schematic diagram explaining sealing principle by showing the time of pressurization to the breaking load generating chamber 39. FIG.
FIG. 17: is a schematic diagram which shows the structure of the vacuum control system 20 of embodiment.
FIG. 18: is a schematic diagram which shows the structure and operation | movement content of the pneumatic circuit 22 of embodiment.
19 is a control block diagram of the vacuum control system 20 of the embodiment.
20 is an explanatory diagram showing a gas flow in the interior of the vacuum chamber 710 of the prior art.
Fig. 21 is an explanatory diagram showing a gas flow in the interior of the vacuum chamber 710 of the prior art.

EMBODIMENT OF THE INVENTION Hereinafter, each embodiment which embodied this invention is described, referring drawings.

(A. Configuration of Vacuum Control System of First Embodiment)

FIG. 1: is sectional drawing which shows the structure of the vacuum control system 10 of 1st Embodiment. 2 is a plan view of the vacuum control system 10 of the first embodiment. The vacuum control system 10 controls the flow of gas supplied to the vacuum vessel 500 for performing a chemical vapor deposition (CVD) process. The vacuum control system 10 includes two vacuum control valves 100 and 200 and one turbomolecular pump 300. The vacuum control valve 100 is connected between the gas outlet 561 of the vacuum vessel 500 and the turbo molecular pump 300. The vacuum control valve 200 is connected between the gas outlet 562 of the vacuum vessel 500 and the turbo molecular pump 300. In this embodiment, the two vacuum control valves 100 and 200 have the same configuration. A dry pump (not shown) is connected in series with the turbomolecular pump 300.

The vacuum container 500 includes a wafer stage 520 for supporting the wafer W as a process target, a gas dispersion unit 510 for dispersing and supplying gas to the process surface Ws of the wafer W, and vacuum control. A shielding plate 530 for protecting the valves 100 and 200 and a pressure measuring unit 631 are provided. In the first embodiment, the process surface Ws is supported by the wafer stage 520 so as to be parallel to a horizontal plane, that is, a plane perpendicular to the direction of gravity. A gas supply pipe 512 and a support structure (not shown) are connected to the gas dispersion unit 510 for supplying gas from the outside of the vacuum container 500.

The gas dispersion part 510 has an opposing surface 511 parallel to the process surface Ws. The opposing surface 511 supplies the gas flow FL from a direction substantially perpendicular to the process surface Ws. The shielding plate 530 has a disk-shaped shape covering each of the gas outlets 561 and 562. The pressure measurement part 631 has the pressure detection part 632 which detects the pressure of the vicinity of the process center Wc in a horizontal plane in this 1st Embodiment. In this specification, "in a horizontal plane" means the thing in the state projected on the horizontal plane. The process center Wc is a preset position in the area where the process is executed. The region in which the process is executed is also called a "process reaction region". Since pressure loss hardly occurs in the process reaction region, the pressure detection unit 632 may be disposed anywhere in the process reaction region.

As can be seen from FIGS. 1 and 2, the housing of the vacuum container 500 includes a dome part 551 having a dome shape for storing the gas dispersion part 510, and two gas discharge pipes 571 and 572. And a lower housing 553 in which the wafer stand 520 is fixed via the mount 554. The dome part 551 has the gas supply port Gc in the vicinity of the process center Wc in a horizontal plane.

As can be seen from FIG. 2, the two gas discharge pipes 571 and 572 are equipped at positions where the process reaction regions are fitted to each other in the horizontal plane. The vacuum control valves 100 and 200 are respectively connected to two gas discharge pipes 571 and 572. The two vacuum control valves 100 and 200 are also connected in opposite directions at positions where the process reaction regions are fitted to each other in the horizontal plane.

The gas flow of the vacuum container 500 is as follows. The gas is supplied to the vacuum container 500 from the gas supply port Gc as shown in FIG. 1. The gas supplied from the gas supply port Gc is supplied as the gas flow FL from the opposite surface 511 of the gas dispersion unit 510 from a direction substantially perpendicular to the process surface Ws as described above. The gas supplied to the process surface Ws is sucked into the gas outlets 561 and 562 by bypassing the shielding plate 530 while performing the CVD process on the process surface Ws. The gas sucked into the gas outlets 561 and 562 is discharged from the turbo molecular pump 300 through the two vacuum control valves 100 and 200. The turbo molecular pump 300 generates effective exhaust speeds Soa and Sob (m ^ 3 / sec) in the vicinity of the inlet 301. The effective exhaust velocity Soa is the share of the flow path via the gas outlet 561. The effective exhaust velocity Sob is a share of the flow path via the gas outlet 562. The two effective exhaust speeds Soa and Sob coincide with each other in the first embodiment.

The vacuum control valve 100 includes an upstream flow passage 141 connected to the gas outlet 561 of the vacuum vessel 500, a downstream flow passage 142 connected to the turbo molecular pump 300, and an upstream flow passage ( The poppet valve body 110 which opens and closes between the 141 and the downstream side flow path 142, the pressure spring 133 which presses the poppet valve body 110 to the closing side, and the poppet valve body 110 by the force of compressed air. A cylinder chamber 135 for moving the cylinder to the open side, an air passage 134 for guiding compressed air into the cylinder chamber 135, an electric field control valve 131 for manipulating the compressed air supplied to the air passage 134, It is provided with the air port 132 for supplying compressed air to the electromagnetic control valve 131, and the exhaust port 137 (refer FIG. 2) which discharges compressed air from the electromagnetic control valve 131. As shown in FIG.

The downstream flow path 142 is provided with a pressure sensor 145 having a detection surface 146 for measuring the pressure P2a inside the flow path. Similarly, the vacuum control valve 200 is provided with the pressure sensor 245 which has the detection surface 246 which measures the pressure P2b inside a flow path. The poppet valve body 110 has the elastic sealing member 112, and can be interrupted between the upstream flow passage 141 and the downstream flow passage 142 by being pressed against the valve seat 143 by the pressing spring 133.

Conductance operation of the vacuum control valve 100 is performed by manipulating the lift amount of the poppet valve body 110. The lift amount means a distance La between the poppet valve body 110 and the valve seat 143 in the present specification. The conductance of the vacuum control valve 100 can be operated as the conductance between the upstream flow passage 141 and the downstream flow passage 142 by adjusting the lift amount La. The vacuum control valve 200 has the same configuration as the vacuum control valve 100 and can operate the conductance in the same manner. The internal pressure of the downstream side flow path 142 is changed by the operation of such conductance. This internal pressure P2a is measured by the pressure sensor 145 which has the detection surface 146 inside the downstream flow path 142, and is sent to the controller 610. Also in the vacuum control valve 200, the internal pressure P2b is similarly measured and sent to the controller 610.

(B. Configuration and Operation Contents of the Vacuum Control System of the First Embodiment)

3 is a control block diagram of the vacuum control system 10 of the first embodiment. The control system includes a first slave loop for controlling the lift amount of the poppet valve body 110 of the vacuum control valve 100 and a second slave for controlling the lift amount of the poppet valve body 210 of the vacuum control valve 200. It is comprised as cascade control of the double loop structure which has a loop and the master loop which controls the internal pressure of the vacuum container 500. As shown in FIG. Each control loop of the slave loop and the master loop can be configured, for example, as a known PID control system. Slave loops and master loops are also called slave controllers and main control sections, respectively.

The first slave loop is for the purpose of bringing the position of the poppet valve body 110 closer to the target value by operating the pressure of the cylinder chamber 135 by the electric field control valve 131 (see FIG. 1) of the electric field controller 130. Is a control loop. The electromotive control valve 131 can operate the internal pressure of the cylinder chamber 135, and can operate a lift amount by the balance with the pressing force of the press spring 133. FIG. The target value is provided to the electric power control valve 131 by the controller 610 as a reference valve opening degree command value pv1 indicating the lift amount of the poppet valve body 110. The lift amount of the poppet valve body 110 is measured by the valve body position sensor 138 and fed back to the electroporation control valve 131. The reference valve opening degree command value pv1 is also called a common opening degree command value.

The first slave loop operates the lift amount of the poppet valve body 110 to reduce the deviation δ1 between the feedback amount and the reference valve opening degree command value pv1. As a result, the first slave loop can control the lift amount of the poppet valve body 110 to approach the reference valve opening degree command value pv1 provided from the controller 610. Manipulating the lift amount is physically equivalent to manipulating the orifice diameter.

Instead of the lift amount, the internal pressure of the cylinder chamber 135 may be measured and used as the feedback amount. However, by feeding back the lift amount, it is possible to suppress a decrease in accuracy caused by nonlinearity between the command value (control input) and the lift amount (openness) from the master loop. This decrease in accuracy is caused by shifting the opening degree ranges of the respective vacuum control valves by an offset value. This configuration secures the linearity of the opening degree and the control input by the actual measurement of the opening degree, thereby realizing suppression of the characteristic change of the vacuum control valve even when the opening degree range is shifted from each other.

The second slave loop is different from the first slave loop in that the target value is not the reference valve opening degree command value pv1 but the valve opening degree command value pv2, and has a different configuration in common. The valve opening degree command value pv2 is a command value generated by adding the offset valve opening degree command value pva with respect to the reference valve opening degree command value pv1. The offset valve opening degree command value pva is a value read from the correction value data storage 620. The offset valve opening degree command value pva is a correction value set such that the effective exhaust speeds Sa and Sb (m ^ 3 / sec) coincide with each other when the whole control system is stable in a steady state. The correction value data storage 620 is also called an offset value storage.

The effective exhaust velocity Sa1 (see FIG. 3) is a flow path from the process center Wc to the inlet 301 of the turbo molecular pump 300 via the gas outlet 561 (see FIG. 1), and the turbo molecular pump. By considering 300 as an integral unit, it means the exhaust velocity when the process center Wc is treated as the inlet of the turbomolecular pump 300. The process center Wc is a pressure measurement position by the pressure measurement part 631. The effective exhaust velocity Sa1 is an exhaust velocity at which reduction due to conductance from the process center Wc to the inlet 301 of the turbomolecular pump 300 is considered, and means as an effective exhaust velocity at the process center Wc. Have On the other hand, the effective exhaust velocity Sb1 (see FIG. 3) is reduced by conductance from the process center Wc to the inlet 301 of the turbomolecular pump 300 via the gas outlet 562 (see FIG. 1). This is the considered exhaust velocity, and has a physical meaning as an effective exhaust velocity at the process center Wc.

The fact that the effective exhaust speeds Sa1 and Sb1 (m ^ 3 / sec) coincide with each other means that the turbomolecular pump 300 generates the same effective exhaust rate at the process center Wc by the conductance. do. On the other hand, in the process center Wc, the route via the gas outlet 561 and the route via the gas outlet 562 share the same pressure, so that the same exhaust flow rate Pa · m ^ 3 / sec is realized. Will be. As a result, the gas is discharged at the same exhaust flow rate from the two gas outlets 561 and 562 disposed at the positions where the process reaction regions are sandwiched with each other.

The master loop is intended for the controller 610 to operate the conductances of the two vacuum control valves 100 and 200 to bring the pressure near the process center Wc of the vacuum vessel 500 to the pressure target value P1t. This is a control loop. The pressure target value P1t is a fixed pressure value preset as a value suitable for the process. Since the valve opening degree command value pv2 is a value corrected by the addition of the fixed offset valve opening degree command value pva with respect to the reference valve opening degree command value pv1, the valve opening degree command value pv2 and the reference valve opening degree command value pv1 is fluctuated integrally. As a result, the two vacuum control valves 100 and 200 move integrally with the offset lift amount as the center position, so that the control principle can be easily simplified without compromising almost instantaneous control even with the control by a single vacuum control valve. It has the advantage of being able to form.

4 is a flowchart showing the operation contents of the control system of the vacuum control system 10 of the first embodiment. In step S100, the user executes the offset valve opening degree command value acquisition process. The offset valve opening degree command value acquisition process is a process of acquiring the characteristic data by operating each of the two vacuum control valves 100 and 200 separately, and obtaining the offset valve opening degree command value pva. The details of the contents of the offset valve opening degree command value acquisition process will be described later.

In step S200, the user performs a pressure target value input process. The pressure target value input process is a process of inputting the pressure target value P1t, which is a preset fixed target value, to the controller 610. The pressure target value P1t is determined as a value suitable for the process performed in the vacuum vessel 500.

In step S300, the controller 610 executes the reference valve opening degree command value determination processing. The reference valve opening degree command value determination processing is a process of gradually calculating the reference valve opening degree command value pv1 in accordance with the deviation δm between the measured pressure inside the vacuum vessel 500 and the pressure target value P1t. The reference valve opening degree command value pv1 is determined based on a control rule stored in the controller 610 in advance. The reference valve opening degree command value pv1 is used as a target value of the first slave loop for controlling the vacuum control valve 100.

In step S400, an offset valve opening degree command value addition process is performed. The offset valve opening degree command value addition process is a process in which the offset valve opening degree command value pva read out from the correction value data storage unit 620 is added to the reference valve opening degree command value pv1. The valve opening degree command value pv2 is generated by this addition process. The valve opening degree command value pv2 is used as a target value of the second slave loop for controlling the vacuum control valve 200. In this way, the two vacuum control valves 100 and 200 are integrally controlled by setting the reference valve opening degree command value pv1 which is a target value offset from each other and the valve opening degree command value pv2 as target values.

In step S500, the lift amount operation processing is executed. The lift amount operation processing is a process in which each of the two poppet valve bodies 110 and 210 is operated in accordance with the reference valve opening degree command value pv1 and the valve opening degree command value pv2. As a result, the orifice diameters of the vacuum control valves 100 and 200 are substantially operated, and the conductance of the vacuum control valves 100 and 200 is operated.

In step S600, the pressure measurement process in a vacuum container is performed. The pressure measuring process in a vacuum container is the process by which the internal pressure of the vacuum container 500 is measured by the pressure measuring part 631. The measurement position is near the process center Wc in the vacuum vessel 500. Thereby, while the pressure in the vicinity of the process center Wc is controlled to approach the pressure target value P1t, the gas is discharged evenly from both of the vacuum control valves 100 and 200.

As described above, in the first embodiment, if the offset valve opening degree command value pva can be obtained, the control principle can be easily established without almost impairing the immediate control even with the control by the single vacuum control valve.

(C. Acquisition method of offset valve opening degree command value in 1st embodiment)

5 is a flowchart showing the contents of the offset valve opening degree command value acquisition process according to the first embodiment. In step S110, the user closes the vacuum control valve 200. Thereby, the influence by the operation | movement of the vacuum control valve 200 is eliminated, and the characteristic data of exhaust by the vacuum control valve 100 can be acquired.

FIG. 6: is explanatory drawing which shows the mode that the vacuum control valve 100 of 1st Embodiment operates by a single body. In the example of FIG. 6, since the vacuum control valve 200 is closed and the vacuum control valve 100 is in an open state, all the supplied gas is supplied to the vacuum control valve 100 through the gas outlet 561. Inhalation will occur. In this way, it can be seen that the characteristic data of the vacuum control valve 100 can be acquired.

In step S120, the user sets a target value. The target value is the pressure target value P1t in the vicinity of the process center Wc and the gas supply amount Q / 2 from the gas supply port Gc. The pressure target value P1t is set as a vacuum pressure suitable for the assumed process. The gas supply amount Q / 2 is set at half as the flow rate which the vacuum control valve 100 and the turbo molecular pump 300 share among the flow rates Q suitable for the assumed process.

In step S130, the user executes vacuum control by the vacuum control valve 100. In preparation for this vacuum control, the user is evacuated by a dry pump (not shown) connected in series with the turbomolecular pump 300 to lower the internal pressure of the vacuum vessel 500 to the molecular region. Next, the turbomolecular pump 300 is started to a stable operation state.

When the internal pressure of the vacuum vessel 500 reaches the vicinity of the pressure target value P1t, the user starts supply of gas at the flow rate Q / 2 and starts the vacuum control by the vacuum control valve 100. Let's do it. In the control system of FIG. 3, this control is operated as cascade control in a state where the master loop and the first slave loop function, and the second slave loop is stopped. In the gas supply control according to the first embodiment of the present invention, the gas supply amount Q / 2 becomes a set value, and the gas is stably supplied at the set value.

The controller 610 transmits the reference valve opening degree command value pv1 to the vacuum control valve 100 as shown in FIG. 8, and performs control of bringing the vacuum pressure P1 close to the pressure target value P1t. . The controller 610 acquires the inlet pressure P2a and the lift amount La of the turbo molecular pump 300 from the vacuum control valve 100. Inlet pressure P2a is measured by the pressure sensor 145 which has the detection surface 146 as the pressure of the downstream flow path 142, and is transmitted to the controller 610. The lift amount La is transmitted from the valve body position sensor 138 to the controller 610 via the electric field control valve 131.

In step S140, the controller 610 detects that the predetermined stable condition is satisfied, and stores the lift amount La in the correction value data storage unit 620 according to the detection. The stable condition may be, for example, that both of the deviation δm of the master loop and the deviation δ1 of the first slave loop are smaller than the preset threshold for a predetermined time. The controller 610 further calculates the effective exhaust velocity Sa1 of the vacuum control valve 100 and stores it in the correction value data storage 620.

7 is an explanatory diagram showing a calculation formula used for calculating the effective exhaust speed Sa1. The effective exhaust speed Sa1 is calculated as follows. First, the controller 610 calculates the conductance C from the vicinity of the process center Wc to the inlet of the turbo molecular pump 300 using the formula F2 (see FIG. 7). Secondly, the controller 610 calculates the effective exhaust velocity Sa1 from the conductance C and the exhaust velocity Sa2 of the turbomolecular pump 300 using the formula F4. Here, the conductance C is the measurement pressure P1m measured by the pressure measuring unit 631 in the vicinity of the process center Wc and the inlet pressure of the turbomolecular pump 300 measured by the pressure sensor 122. It can calculate from the measured value of P2a). In addition, the exhaust velocity Sa2 of the turbomolecular pump 300 can be computed by the continuous formula F5. In this way, the controller 610 calculates the effective exhaust speed Sa1 of the vacuum control valve 100, and stores the calculation result in the correction value data storage unit 620.

Formulas F1 to F4 are based on the vacuum theory and are determined as follows. Formula F2 is derived by mathematically modifying Formula F1. Calculation formula F1 is the gas supply amount Q / 2, the measured value of the inlet pressure P2a of the turbomolecular pump 300, and the vacuum pressure P1 (measurement value) near the process center Wc with respect to the definition formula of conductance. Is substituted. Formula F4 is derived by mathematically modifying Formula F3. Calculation formula F3 is a theoretical formula showing the relationship between the exhaust velocity, the conductance, and the effective exhaust velocity Sa1. On the other hand, the formula F5 is determined by treating the gas flow as a one-dimensional flow of the compressive fluid and using a constant mass flow rate.

In addition, in 1st Embodiment, in order to demonstrate the concept of invention easily, conductance C is computed from the measured value of the inlet pressure P2a of the turbomolecular pump 300. FIG. However, in the vacuum container 500 of 1st Embodiment, the lift amount La when the measured pressure P1m measured by the pressure measuring part 631 in the vicinity of the process center Wc matches the pressure target value P1t. ) Is enough to get. This is because the valve lift amount La for realizing the appropriate pressure P1t can be obtained at a flow rate (partial share = Q / 2) suitable for the process. In other words, in the gas supply amount Q / 2, the valve lift amount La for realizing an effective effective exhaust speed Sa1 in the vicinity of the process center Wc can be obtained (P1 ×). Sa1 = Q / 2). In this way, the calculation of the conductance C is not necessary.

In step S150, the user stops control by the vacuum control valve 100 to close the valve. The closing of the vacuum control valve 100 is executed after stopping the gas supply. The stop of the turbomolecular pump 300 is performed after the closing of the vacuum control valve 100 to prevent breakage of the turbomolecular pump 300.

In step S160, the user sets a target value of the vacuum control valve 200. The set target value is the same as the target value of the vacuum control valve 200. That is, the target value is the pressure target value P1t in the vicinity of the process center Wc and the gas supply amount [Q / 2: the share of the vacuum control valve 200] from the gas supply port Gc.

In step S170, the user executes vacuum control by the vacuum control valve 200. The method of vacuum control is the same as that of vacuum control by the vacuum control valve 100 (step S130). In step S180, the controller 610 detects that the preset stable condition is satisfied, and stores the lift amount Lb in the correction value data storage unit 620 according to the detection. The acquisition method of the lift amount Lb is the same as the acquisition method of the lift amount La.

Thereby, in each shared flow volume Q / 2, the lift amount La of the vacuum control valve 100, and the command value Ca at this time, when it matches the pressure target value P1t of the process center Wc, The lift amount Lb of the vacuum control valve 200 and the command value Cb at this time can be acquired, respectively. The lift amount La is a lift amount of the vacuum control valve 100 for setting the pressure at the process center Wc as the pressure target value P1t in the shared flow rate Q / 2. The lift amount Lb is the lift amount of the vacuum control valve 200 for setting the pressure at the process center Wc as the pressure target value P1t in the shared flow rate Q / 2.

Therefore, when the vacuum control by the vacuum control valves 100 and 200 of both functions is functioned, it will be exhausted by the same allocating flow rate Q / 2 in both gas supply amount Q. FIG. This vacuum control is generated at the process center Wc by a route through the gas outlet 561 and a route through the gas outlet 562 by conductance of each conductance of the vacuum control valves 100 and 200. The effective exhaust speeds Sa1 and Sb1 (m ^ 3 / sec) which are present can also be regarded as control to coincide with each other. The offset valve opening degree command value pva can be calculated as a difference between the command value Ca and the command value Cb.

Thus, the vacuum control system 10 of 1st Embodiment can calculate the offset valve opening degree command value pva semi-automatically, and can store it in the correction value data storage part 620. As shown in FIG. Thereby, the control system of 1st Embodiment can be made to function. As a result, the flow of the gas in the process surface Ws can suppress the influence on the operation | movement of the vacuum control valve in a vacuum control system, and it can realize the uniform flow in the vicinity of the process surface Ws.

In the first embodiment, in particular, the two vacuum control valves 100 and 200 move integrally, and the center of the opening of the valve also moves in the same way with respect to the direction of gravity, so that the flow of gas due to the center movement of the opening of the valve is biased. Also effectively suppressed.

In addition, in the above-mentioned embodiment, although the pressure sensor 145 (refer FIG. 6) is made the structure which measures the pressure in an inside of a flow path in the downstream flow path by the vacuum control valve 100 side, it is shown in FIG. It is good also as a structure which measures a pressure in each of the gas discharge ports 561 and 562 like a modified example shown. In this modified example, the pressure of the gas discharge port 561 is measured by the pressure sensor 581a which has the pressure detection surface 582a inside the gas discharge port 561. Moreover, on the vacuum control valve 200 side, the pressure sensor 581b which has the detection surface 582b which similarly measures the pressure P2b inside a flow path is provided. Also in such a structure, the same handling as that of embodiment mentioned above using calculation formula F1-F5 is possible.

As such, the measurement position of the pressure is either one of the position between the gas outlet 561 and the inlet 301 of the turbomolecular pump, and one of the position between the gas outlet 562 and the inlet 301 of the turbomolecular pump. It is good to be equipped with. However, if the pressures P2a and P2b are measured downstream of the vacuum control valves 100 and 200 as in the above-described embodiment, the pressures P2a and P2b fluctuate sensitively to the valve lift amount, so that they are offset with high precision. There is an advantage that a valve opening degree command value can be obtained.

[D. Configuration of Vacuum Control System 20 of Second Embodiment]

The vacuum control system 20 of the second embodiment differs from the vacuum control system 10 of the first embodiment in that a plurality of vacuum control valves 30 having low hysteresis characteristics are used. Since the vacuum control valve 30 has a low hysteresis characteristic, it enables high responsiveness and precise conductance operation, thereby remarkably improving the vector operability of the flow of the reaction gas.

In addition, although the system which operates the single vacuum control valve 30 and the single vacuum control valve 30 is demonstrated in the following description, in the application to this invention, the vacuum control valve of 1st Embodiment ( 100 and 200).

9 is a cross-sectional view showing the configuration of the vacuum control valve 30 at the time of non-energization (valve closing). 10 is an enlarged cross-sectional view showing the configuration of the rod cover 81 of the vacuum control valve 30 at the time of non-energization. 11 is a cross-sectional view showing the configuration of the vacuum control valve 30 at the time of valve expansion. The vacuum control valve 30 is provided with the control valve main body 43, the cylinder tube 31, and the operation member 32. The control valve body 43 has a cylindrical shape extending in the movement direction (axial direction) of the operation member 32. The control valve main body 43 is formed with a valve box 45 which is a substantially cylindrical recess that is opened on the cylinder tube 31 side in the axial direction. The opening of the valve box 45 is blocked by a rod cover 81 having a through hole 82 through which the operation member 32 slides.

The operation member 32 includes a valve body 33 for manipulating the valve opening degree of the vacuum control valve 30 in the valve box 45, a rod 32r passing through the through hole 82, and a rod 32r. The piston 51 is connected to the edge part. The valve body 33 is connected to the rod 32r, and can move the operation member 32 in the axial direction to change the lift amount La. The lift amount La corresponds to the valve opening degree in the present embodiment. The operation member 32 corresponds to an operation part.

The valve body 33 has a function of blocking the flow path by contacting the valve seat 42 formed on the control valve body 43. The passage of the flow path is performed by contacting the valve body 33 to the valve seat 42 and isolating the secondary port 44 from the valve box 45 inside the valve box 45. Sealing at the time of interruption | blocking is implement | achieved by contacting the valve seat 42 with the O-ring 75 which the one part protruded from the valve body 33, and crushing. The valve seat 42 is an annular region facing the valve body 33 in the axial direction, for example, and has a small surface roughness formed around the connection port with the secondary port 44. The O-ring 75 has an annular shape at a position facing the valve seat 42 in the axial direction.

The piston 51 has an annular shape extending radially toward the inner circumferential surface 53 of the cylinder tube 31, and the valve opening degree operation chamber 36 closed on the inner circumferential surface 53 of the cylinder tube 31 is also provided. (Refer FIG. 11) is formed. The cylindrical member 51v which has a cylindrical shape extended in the axial direction to the opposite side of the valve opening degree operation chamber 36 in the axial direction is connected. The bellows 34 which seals the valve opening degree operation chamber 36 is connected to the piston 51.

The valve opening operation chamber 36 is a donut having a variable volume surrounded by the bellows 34, the rod cover 81, the rod 32r, and the piston 51 (the bellows retainer 52). It is formed as a shaped sealed space. The end of the inner circumference of the bellows ram 34 is fastened with a screw 54 between the piston 51 and the bellows retainer 52. On the other hand, the end portion 34a of the bellows ram 34 is sandwiched between the cylinder tube 31 and the rod cover 81. As a result, the bellows 34 and the rod cover 81 and the bellows 34 and the cylinder tube 31 are sealed (sealed). The valve opening operation chamber 36 is formed by dividing an internal space formed by the inner circumferential surface 53 by the bellows 34. The valve opening degree operation chamber 36 can be supplied with operation air via the valve opening air passage 37 and the connection passage 87. In addition, the supply method of operation air is mentioned later. The operation air corresponds to the working fluid.

The bellows ram 34 has a silk hat-shaped shape and is a flexible space partition member capable of following or rolling (moving the refolded portion) in a long stroke (stroke). The bellows ram 34 is a bellows ram that seals the gap between the outer circumferential surface 51s (see FIG. 11) of the piston 51 and the inner circumferential surface 53 of the cylinder tube 31 while following the operation of the piston 51. . The bellows 34 is also called a rolling diaphragm, and does not form a surface contact that causes friction between the operating member 32 and the valve opening degree operation chamber 36, so that the sliding resistance is extremely small, resulting in low hysteresis characteristics. It has unique characteristics such as micro pressure responsiveness and high sealability. The bellows ram 34 is configured to secure a clearance between the outer circumferential surface 51s and the inner circumferential surface 53 by the linear bearing 65 so as to smoothly move the rolling. The detail of the linear bearing 65 is mentioned later.

Since the bellows | ramp 34 seals the sliding part between the inner peripheral surface 53 of the largest diameter cylinder tube 31 and the piston 51 in the vacuum control valve 30, it operates remarkably except the friction surface. The sliding frictional resistance of the member 32 can be made small. As a result, adjustment of the lift amount La with high response in low hysteresis characteristics is realized by the pressure operation of the operation air supplied from the electric field control valve 26 to the valve opening air flow path 37. In addition, the operation member 32 may be configured to move using an electric motor.

On the other hand, as shown in FIG. 10, the sealing between the rod 32r and the rod cover 81 is comprised as follows. In the through hole 82 of the rod cover 81, a mounting recess 83 is formed at a position close to the side of the valve box 45, and at a position closer to the cylinder tube 31 side than the mounting recess 83. The mounting groove 84 is formed. The mounting recess 83 is equipped with a first short diameter load seal 76 and a second short diameter load seal 77 having relatively low pressure resistance and small dynamic frictional resistance. The mounting groove 84 is equipped with a packing 74 having a relatively high pressure resistance. On the other hand, the rod cover 81 is provided with a leak detection port 85 which communicates with the mounting recess 83 between the packing 74 and the first short diameter load seal 76 and penetrates to the outside.

The leak detection port 85 can detect the leakage in the packing 74 and the leakage in the first short diameter load seal 76 and the second short diameter load seal 77. Leakage in the packing 74 can be detected as a leak of operation air. Leakage in the first short diameter load seal 76 and the second short diameter load seal 77 injects helium gas into the leak detection port 85 and is connected to a helium leak detector (not shown). It can detect by making 45 into a vacuum state.

The piston 51 is urged by the urging spring 55. The pressing spring 55 applies a pressing force to the piston 51 of the operation member 32 in a direction in which both the lift amount La and the volume of the valve opening degree operation chamber 36 decrease. The pressing spring 55 is accommodated in the space surrounded by the inner circumferential surface 53 of the cylinder tube 31 and the head cover 61 having an annular shape. One of the pressing springs 55 is in contact with the valve 51 on the opposite side (back side) in the axial direction with the valve opening degree operation chamber 36. The other side of the pressing spring 55 is in contact with the head cover 61.

The head cover 61 has a cylindrical part 61b which has a cylindrical shape, and the sliding convex part 61a which has a cylindrical shape which has a diameter smaller than the cylindrical part 61b. The head cover 61 shares the center axis with the sliding convex part 61a and the cylinder part 61b. The diameter difference between the sliding convex part 61a and the cylinder part 61b forms the stroke limiting surface 61e. The stroke limiting surface 61e is a contact surface for limiting the amount of lift of the piston 51 by contacting the stroke limiting end 51e formed on the piston 51. As a result, the stroke of the piston 51 is limited in the upward direction (the lift amount La increase direction) by the stroke limiting surface 61e, while the downward direction (the lift amount La reduction direction) is the valve seat 42. It is limited by).

The sliding convex part 61a is accommodated in the interruption load generation chamber 39 formed in the inside of the operation member 32. As shown in FIG. The breaking load generating chamber 39 is formed inside the valve opening operation chamber 36 with respect to the centerline extending in the operation direction of the operating member 32. Thereby, the interruption load generating chamber 39 is equipped in the position which overlaps with respect to the valve opening degree operation chamber 36 in the operation direction of the operation member 32. FIG. As a result, the enlargement of the vacuum control valve 30 resulting from the equipment of the breaking load generation chamber 39 (especially the enlargement of the operation direction of the operation member 32) can be suppressed. Moreover, since the sliding radius of the head cover 61 can be made small, generation | occurrence | production of the sliding resistance resulting from the equipment of the breaking load generation chamber 39 can also be suppressed.

Application of the breaking load by the breaking load generating chamber 39 may improve the manufacturability of the vacuum control valve 30. It is because manufacture can be made easy by reducing the set load (load at the time of valve closing) of the press spring 55 at the time of manufacture. That is, the pressing spring 55 is equipped with a spring coefficient for generating the requested breaking load and an initial bending amount for generating an initial load (preload) in the prior art when breaking (when the lift amount La is zero). Is requested.

As a result, both the spring coefficient and the initial deflection amount become excessive with the enlargement of the diameter of the vacuum control valve 30. Therefore, it has been found by the present inventors that not only the enlargement of the vacuum control valve 30 but also the manufacturing becomes difficult. . In this configuration, however, the initial load of the pressing spring 55 can be reduced by generating the breaking load in the head cover 61 and the breaking load generating chamber 39.

The linear bearing 65 restrains the positional relationship of the radial direction (direction perpendicular to the axial direction) between the head cover 61 and the guide rod 56, while axial direction (moving direction of the operation member 32) with small friction. Bearings to allow relative reciprocating motion. The linear bearing 65 is a space inside the inner circumferential surface of the sliding convex portion 61a having a cylindrical shape, and is disposed outside the outer circumferential surface of the guide rod 56.

Since the guide rod 56 is connected to the operation member 32, the linear bearing 65 can also maintain (restrain) the positional relationship (gap) between the piston 51 and the inner circumferential surface 53. Thereby, the bellows 34 can move the operation member 32 with respect to the cylinder tube 31 with little friction by moving the retracted part smoothly.

The guide rod 56 is equipped with a valve body position sensor 35 for measuring the operation amount of the guide rod 56 with respect to the head cover 61. The insertion pipe 35b into which the probe 35a of the valve body position sensor is inserted is connected to the guide rod 56 via the adapter 35c. The valve body position sensor 35 can generate an electrical signal in accordance with the insertion length of the probe 35a into the insertion pipe 35b. Since the operation amount of the guide rod 56 with respect to the head cover 61 can be plotted as the variation amount of the insertion length, the lift amount La can be measured according to the variation amount. As the valve body position sensor 35, a linear pulse coder (registered trademark) or the like can be used, for example.

The head cover 61 has two cylindrical sliding surfaces that share the central axis. The first sliding surface is a sliding surface between the outer circumferential surface 61as and the inner circumferential surface 63 of the sliding convex portion 61a. The second sliding surface is a sliding surface between the inner circumferential surface 62as of the sliding convex portion 61a and the guide rod 56. The clearance (gap) of the first sliding surface and the second sliding surface is accurately held by the linear bearing 65.

As described above, the linear bearing 65 is disposed between the sliding convex portion 61a and the guide rod 56, and the positional relationship between the sliding convex portion 61a and the linear bearing 65 is mutual. Also, it is held regardless of the operation of the operation member 32. Thereby, the precision of the clearance gap between the breaking load generation chamber 39 and the sliding convex part 61a can be improved easily. On the other hand, the linear bearing 65 is held regardless of the operation of the operating member 32 also with respect to the positional relationship with the packing 74 provided in the through hole 82, and the piston sealed with the bellows 34. It is held closer than the sliding surface between the 51 and the inner peripheral surface 53. As a result, the sliding surface having a strict demand for the accuracy of the clearance of the sliding surface is disposed in the vicinity of the linear bearing 65, so that both the improvement of the sealing performance and the reduction of the sliding resistance can be achieved.

In the first sliding surface, a mounting groove 78 (see FIG. 10) having a concave shape is formed in the outer circumferential surface 61as over the entire circumference of the outer circumference thereof, and the V-shaped packing ( 70b) is mounted. In the second sliding surface, a mounting groove 79 having a concave shape is formed in the inner circumferential surface 62as, and a V-shaped packing 70a is attached to the mounting groove 79. The V-shaped packings 70a and 70b are also called V-packings.

Next, with reference to FIG. 12, the method of operating the lift amount La of the vacuum control valve 30 is demonstrated. 12 is a cross-sectional view showing an operating state at the time of controlling the vacuum pressure of the vacuum control valve 30. As described above, the vacuum control valve 30 adjusts the lift amount La, which is the distance between the valve body 33 and the valve seat 42, as the valve opening degree, so that the primary side port 41 and the secondary side port ( 44) can conduct the conductance between. The lift amount La is adjusted by moving the position of the operation member 32 relative to the valve seat 42. Conductance means that fluid flows easily in a flow path.

The lift amount La is operated by the balance between the driving force to the operation member 32 and the pressing force of the pressing spring 55 opposite to the driving force. The driving force to the operation member 32 is generated by the action of the pressure of the operation air inside the valve opening degree operation chamber 36. In the control of the lift amount La, a reduction in the frictional force due to the relative movement between the operation member 32 and the cylinder tube 31 is expected. This is because the frictional force causes hysteresis and is a large factor that hinders precise control.

The operating member 32 has three friction surfaces between the cylinder tubes 31 as shown in FIG. The first friction surface is a friction surface between the packing 70b attached to the mounting groove 78 and the inner circumferential surface 63. The second friction surface is a friction surface between the packing 70a attached to the mounting groove 79 and the guide rod 56. The third friction surface is a friction surface between the packing 74 attached to the through hole 82 of the rod cover 81 and the outer circumferential surface of the rod 32r.

The sliding resistance is reduced by the 3rd friction surface mainly reducing the operation pressure of the valve opening degree operation chamber 36. Reduction of the operation pressure of the valve opening degree operation chamber 36 can be realized by reducing the set load (load at the time of valve closing) of the pressing spring 55 as described above. Moreover, according to the experiment of this inventor, when surface roughness Ra of the outer peripheral surface of the rod 32r is set to about 0.2, it is confirmed that the compatibility of the vacuum leak characteristic required for reducing a sliding resistance can be ensured. The third friction surface may be configured to be sealed by covering the operation member 32 with a bellows.

FIG. 13 is an enlarged cross-sectional view showing a friction surface between the packing 70 attached to the first friction surface, that is, the mounting groove 78, and the inner circumferential surface 63. As shown in FIG. The packing 70 is a V-shaped packing having a heel portion 71 and a pair of lip portions 72a and 72b divided into two branches. The packing 70 is configured such that the pair of lip portions 72b face the breaking load generating chamber 39, and the surface pressure is increased by the pressure from the breaking load generating chamber 39. The second friction surface is sealed like the first friction surface.

In the design of the sliding portion, the relationship between the clearance S2 of the sliding portion, the depth S1 of the mounting groove 78, and the size of the width direction of the pair of lip portions 72a, 72b of the packing 70b. Becomes the design parameter. In this embodiment, since the airtightness of the breaking load generation chamber 39 is required only when the valve body 33 contacts the valve seat 42 and produces a breaking load, the amount of crushing of the packing 70b is mentioned later. Can be made small. Thereby, the amount of friction between the packing 70b and the inner peripheral surface 63 can be reduced, and hysteresis can be reduced.

Next, with reference to FIGS. 14-16, the sealing mechanism by the packing 70b is demonstrated in detail. Fig. 14 is a schematic diagram illustrating the sealing principle by showing the mounting state of the packing 70b. FIG. 15: is a schematic diagram explaining the sealing principle by showing the state at the time of non-pressurization of the breaking load generating chamber 39. As shown in FIG. FIG. 16: is a schematic diagram explaining sealing principle by showing the time of pressurization to the breaking load generating chamber 39. FIG. In FIG. 14 and FIG. 16, surface pressure distribution Pd1, Pd2 of the packing 70b is shown. Since the vacuum control valve 30 is pressurized to the breaking load generating chamber 39 only at the time of breaking, the pressurization to the breaking load generating chamber 39 is not performed in the state where the lift amount La is being controlled.

As shown in FIG. 15, the packing 70b is attached to the mounting groove 78 in the state which was elastically deformable by the amount of crushing Q. As shown in FIG. In the non-pressurization, the contact surface pressure and the surface pressure area of the packing 70b are extremely small as shown as the surface pressure distribution Pd1. This is because the surface pressure distribution Pd1 is a surface pressure distribution generated due to the stiffness and the amount of crushing Q of the pair of lip portions 72a and 72b. Thereby, in the state in which the vacuum control by the electromagnetic control valve 26 is performed (at the time of the non-pressurization of the breaking load generation chamber 39), it is extremely small between the breaking load generation chamber 39 and the head cover 61. Dynamic friction will occur.

On the other hand, as shown in Fig. 16, the breaking load generating chamber 39 can realize sufficient sealing performance as shown by the surface pressure distribution Pd2 at the time of applying the breaking load. In addition, in the application of the cutoff load, since the valve body 33 is in a cutoff state in contact with the valve seat 42, a relative movement is not required between the cutoff load generating chamber 39 and the head cover 61. It can be seen that the occurrence of dynamic friction does not cause any problem. Furthermore, the present inventors have found that the leakage at the time of sliding movement is acceptable, so that the surface pressure distribution Pd1 can also be reduced. Thus, in order to equip the function of generating the breaking load, even if the breaking load generating chamber 39 and the sliding convex portion 61a are provided, the sliding movement can realize a design in which the sliding movement is not newly caused by hysteresis. It became.

Next, with reference to FIGS. 17-19, the vacuum control system 20 which uses the vacuum control valve 30 is demonstrated.

FIG. 17: is a schematic diagram which shows the structure of the vacuum control system 20 of embodiment. The vacuum control system 20 includes a vacuum vessel 90 for performing an etching process, a vacuum control valve 30, a controller 21, a pneumatic circuit 22, a turbo molecular pump 300, and a turbo The vacuum pump has a dry pump connected in series with the molecular pump 300. The reactive gas G is supplied to the vacuum vessel 90 at a constant supply amount, and is exhausted by the turbo molecular pump 300 through the vacuum control valve 30. The vacuum pressure of the vacuum vessel 90 is controlled by manipulating the conductance of the vacuum control valve 30. The turbo molecular pump 300 corresponds to a vacuum pump.

The vacuum vessel 90 includes a reaction gas supply hole 91 to which the reactive gas G is supplied, an exhaust hole 93, and a vacuum pressure sensor 92. The reactive gas supply hole 91 is supplied with a certain amount of reactive gas G measured by a mass flow sensor (not shown). The primary port 41 of the vacuum control valve 30 is connected to the exhaust hole 93. The vacuum pressure sensor 92 measures the vacuum pressure inside the vacuum vessel 90 and transmits an electric signal to the controller 21. The vacuum pressure is used for the operation of the vacuum control valve 30 by the controller 21.

The internal pressure of the valve opening operation chamber 36 is operated by supplying or exhausting the operation air from the pneumatic circuit 22 through the valve opening air flow passage 37. The pneumatic circuit 22 is connected to the working fluid supply part 95 on the high pressure side for supplying the operation air, and the working fluid exhaust part 96 on the low pressure side for exhausting the operation air.

The shutoff load is supplied from the pneumatic circuit 22 to the shutoff air passage 38 to move the valve body 33 to the valve seat 42, and then move the valve body 33 to the valve seat. It functions as a load pressed against 42. The blocking load acts as a force with the pressing load by the pressing spring 55.

In this embodiment, the interruption load is applied, for example, when the controller 21 receives the vacuum pump stop signal from the turbomolecular pump 300 and emergency stops the vacuum control system 20. Below, the operation content in each operation mode including an emergency stop is demonstrated. The controller 21 corresponds to a control unit. The vacuum pump stop signal is, for example, a signal transmitted when the vacuum pump is stopped or when the rotation speed of the turbo molecular pump 300 is very low.

Next, with reference to FIG. 18, the operation | movement content of the pneumatic circuit 22 and the vacuum control valve 30 is demonstrated. FIG. 18: is a schematic diagram which shows the structure and operation content of the pneumatic circuit 22 of embodiment. The pneumatic circuit 22 is a circuit which supplies operation air according to the instruction | command from the controller 21, and operates the vacuum control valve 30 by this. The pneumatic circuit 22, the electric field control valve 26, and three electromagnetic valves SV1, SV2, SV3 are provided. The electromotive control valve 26 has an air supply valve 26a connected to the high pressure side of the operation air, and an exhaust valve 26b connected to the exhaust side of the operation air.

In the present embodiment, the controller 21 is configured as a programmable logic controller (PLC) incorporating two PID control circuits 24a and 24b. The programmable logic controller 21 is a logic circuit capable of realizing high reliability control using, for example, ladder logic. The two PID control circuits 24a and 24b are used for feedback control of the vacuum pressure of the vacuum vessel 90, although details will be described later. The controller 21 transmits the on-off command to each of the three electromagnetic valves SV1, SV2, and SV3 and the pulse width modulation signal to the electromotive control valve 26 to the pneumatic circuit 22. The electromagnetic valve SV2 and the electromagnetic valve SV3 are also called the first electromagnetic valve and the second electromagnetic valve, respectively.

The solenoid control valve 26 is for valve opening of the compressed air supplied from the outside by, for example, manipulating the valve opening time (duty) of the air supply valve 26a and the exhaust valve 26b by a known pulse width modulation method. The supply pressure to the air flow path 37 can be operated. The solenoid control valve 26 increases the valve opening time (duty) of the air supply valve 26a and decreases the valve opening time of the exhaust valve 26b to the operating member 32 in the valve opening degree operation room 36. The working air pressure can be raised. As a result, the lift amount La of the valve body 33 can be increased.

On the other hand, the electromotive control valve 26 reduces the valve opening time (duty) of the air supply valve 26a, and increases the valve opening time of the exhaust valve 26b, so that the operation member 32 is operated in the valve opening operation chamber 36. The air pressure acting on) can be lowered, whereby the lift amount La of the valve body 33 can be reduced by the load from the pressing spring 55.

The electromagnetic valve SV1 is an electromagnetic valve that switches the flow path connected to the electromagnetic valve SV2 to one of the electro-pneumatic control valve 26 and the working fluid supply unit 95. Connected. The electromagnetic valve SV2 is an electromagnetic valve that switches the flow path connected to the valve opening air flow passage 37 to one of the electromagnetic valve SV1 and the working fluid exhaust portion 96. (96). The electromagnetic valve SV3 is an electromagnetic valve that switches the flow passage connected to the shutoff air flow passage 38 to either the working fluid supply portion 95 or the working fluid exhaust portion 96. 95).

Next, with reference to Table T, the content of each operation mode of the pneumatic circuit 22 is demonstrated. Table T is a table which shows the energization state of three electromagnetic valves SV1, SV2, SV3 in each operation mode. In Table T, on and off are described as "ON" and "OFF", respectively.

In the operation mode at the time of emergency stop of the vacuum control system 20, the electric field control valve 26 and the three electromagnetic valves SV1, SV2, SV3 are all turned off. Emergency stop is an operating mode as a worst case defined in the system design of the vacuum control system 20, for example, when the controller 21 receives a vacuum pump stop signal from a dry pump (not shown). The dry pump is connected to the turbo molecular pump 300 in series and is a pump used for evacuation. In this operation mode, the entire atmospheric pressure is applied as the differential pressure between the secondary port 44 in the atmospheric open state and the primary port 41 on the vacuum side. This differential pressure load is applied in the direction of increasing the lift amount La with respect to the valve body 33, and is spaced apart from the valve seat 42 in the direction in which the air flows back to the vacuum container 90. Will work. In the emergency stop of the present embodiment, the reverse flow can be prevented against the above-mentioned differential pressure by the breaking load.

In this manner, the working fluid supply part 95 on the high pressure side is connected to the shutoff air flow path 38, and the working fluid exhaust part 96 on the exhaust side is connected to the valve opening air flow path 37. As a result, the air pressure in the breaking load generating chamber 39 to apply the breaking load is increased, so that the room of the valve opening degree operation chamber 36 to apply the load at the valve opening side (lift amount La increase) to the atmospheric pressure. Will be degraded. As a result, the valve body 33 connected to the operation member 32 moves rapidly in the direction of the valve seat 42 to bring the vacuum control valve 30 to the closed state (cut off) and to apply the breaking load. Continue.

In addition, the electromagnetic valve SV3 may be comprised so that the flow path connected to the blocking air flow path 38 may be connected to the working fluid exhaust part 96 at the time of non-energization. However, as mentioned above, when it is comprised so that it may be connected to the working fluid supply part 95 at the time of non-energization, power supply to the pneumatic circuit 22 will be stopped at the time of a power failure, and as shown by the arrow of Table T, The operating mode can be the same as in the emergency stop.

In this manner, in the power failure or emergency stop of the vacuum control system 20, the shutoff load can be applied while closing the vacuum control valve 30 in either of the operating modes. As a result, in the vacuum control system 20 of this embodiment, in the state in which the electric power supply to the pneumatic circuit 22 was stopped, the valve | bulb by the press force of the press spring 55 and the pressurization of the interruption load generation chamber 39 is pressed. The sieve 33 moves to the valve seat 42, and the air circuit is comprised so that a breaking load may be applied.

In such a configuration, it is ensured that the circuit is always shut off even when the power is turned off or in the case of a power failure. Therefore, there is an advantage that a system design in consideration of ensuring safety during emergency stop or power failure can be easily realized. In addition, in this embodiment, since the controller 21 enters the operation mode of emergency stop in accordance with the reception of the vacuum pump stop signal, the pressure of the secondary port 44 is for example caused by the unpredictable stop of the turbomolecular pump 300. Even if this rises, it also has the advantage that a blocking state can be secured.

Next, in the operation mode in which the vacuum control valve 30 is closed, the two electromagnetic valves SV1 and SV2 are turned off, while the electromagnetic valve SV3 is turned on. This operating mode puts the vacuum control valve 30 in the closed state when the turbo molecular pump 300 is in a normal operating state. In this operation mode, the pressure spring 55 is set such that a load such that the O-ring 75 is crushed with an appropriate amount of crushing in order to keep the vacuum control valve 30 closed in a normal operating state. Thereby, durability of the O-ring 75 can be improved.

Thus, since this embodiment is equipped with the mechanism which generate | occur | produces the breaking load for responding at the time of an emergency, the pressing force of the press spring 55 is set so that the O-ring 75 may be crushed by the amount of crushing suitable for normal operation. It can also provide design freedom.

On the other hand, in the operation mode in which the vacuum control valve 30 is opened, all three electromagnetic valves SV1, SV2, SV3 are turned on. Thereby, the high pressure side working fluid supply part 95 is connected to the valve opening air flow path 37 via the two electromagnetic valves SV1 and SV2 of an on state. On the other hand, the working fluid exhaust part 96 on the exhaust side is connected to the blocking air flow path 38 via the electromagnetic valve SV3 in the on state. On the other hand, the electromotive control valve 26 is in the state in which the flow path was isolate | separated from the valve opening air flow path 37 by the electromagnetic valve SV1 of an ON state. Thereby, the vacuum control valve 30 can be made to open rapidly (the state in which the lift amount La is the maximum) irrespective of the operation state of the electromotive control valve 26. FIG.

Finally, in the operation mode in which the vacuum control valve 30 controls the vacuum pressure, the electromagnetic valve SV1 is turned off while the two electromagnetic valves SV2 and SV3 are turned on. Thereby, the working fluid supply part 95 of the high pressure side passes through the electric field control valve 26, the electromagnetic valve SV1 in the off state, and the electromagnetic valve SV2 in the on state, in order. The flow path is connected to the. On the other hand, the working fluid exhaust part 96 on the exhaust side passes through the electromagnetic valve SV3 in the on state, and the flow path is connected to the blocking air flow path 38. Thereby, the electromotive control valve 26 can supply operation air from the valve opening air flow path 37, and can operate the internal pressure of the valve opening degree operation chamber 36, and can adjust the lift amount La.

Next, with reference to FIG. 19, the control content of the vacuum control system 20 is demonstrated. 19 is a control block diagram of the vacuum control system 20 of the embodiment. This control system is a dual having a slave loop SL for controlling the lift amount La of the valve body 33 of the vacuum control valve 30 and a master loop ML for controlling the internal pressure of the vacuum vessel 90. It is comprised as cascade control of a loop structure. Each control loop of the slave loop SL and the master loop ML can be configured, for example, as a known PID control system.

The slave loop SL manipulates the internal pressure of the valve opening degree operation chamber 36 by the electromotive control valve 26 to bring the lift amount La of the valve body 33 close to the valve opening degree command value Vp. A control loop whose purpose is to make In the slave loop SL, the PID control circuit 24b generates a control signal in accordance with the deviation δm between the valve opening degree command value Vp (target value) and the lift amount La (measurement value) to generate a pulse width modulation signal. Is transmitted to the electro-pneumatic control valve 26. The electromotive control valve 26 adjusts the driving force to the operation member 32 to which the valve body 33 is mounted by operating the internal pressure of the valve opening degree operation chamber 36 in accordance with the pulse width modulation signal.

The lift amount La is measured by the valve body position sensor 35 and used as the feedback amount by the PID control circuit 24b. Thereby, the vacuum control valve 30 can feedback-control the lift amount La. Thereby, the conductance of the flow path between the vacuum vessel 90 and the turbo molecular pump 300 can be adjusted.

In the master loop ML, the PID control circuit 24a determines the valve opening degree command value Vp in accordance with the deviation δp between the target pressure value Pt and the measured pressure value Pm set in advance, and determines the PID control circuit ( 24b). The measurement pressure value Pm is the pressure inside the vacuum container 90 measured by the vacuum pressure sensor 92. The PID control circuit 24a adjusts the valve opening degree command value Vp so that the measured pressure value Pm approaches the target pressure value Pt.

In addition, the feedback loop of the lift amount La may be removed, and it may be configured as a simple single loop control for operating the internal pressure of the valve opening degree operation chamber 36 so that the deviation? P is close to zero. However, if the double loop structure which feeds back the lift amount La is made, the fall of the precision resulting from nonlinearity of the command value (control input) and lift amount (open degree) from the master loop ML can be suppressed. This decrease in accuracy is caused by shifting the opening degree ranges of the vacuum control valves by an offset value. This configuration is configured such that the characteristics of the vacuum control valve are flat in any opening degree range by securing the linearity of the opening degree and the control input by the actual measurement of the opening degree.

The vacuum control system 20 also has an open loop AL for applying a blocking load to the valve body 33 via the operation member 32. The programmable logic controller 21 turns off both electromagnetic valves SV2 and SV3, and generates a breaking load by applying air pressure to the breaking load generating chamber 39 (refer FIG. 10). The magnitude of the breaking load can be set in advance by appropriately setting the inner diameter of the breaking load generating chamber 39 and the external shape of the head cover 61 irrespective of whether the electromagnetic valve SV1 is turned on or off.

This embodiment described in detail above has the following advantages.

In the vacuum control valve 30 of the second embodiment, the bellows are sealed between the inner circumferential surface of the main cylinder with the largest diameter and the outer circumferential surface of the main piston, so that the sliding resistance can be reduced to alleviate the hysteresis. Thereby, since the vacuum control valve 30 of 2nd Embodiment can implement | achieve the accurate operation in low hysteresis, and the accurate measurement of the operation state easily, it can realize the precise and high responsive vacuum control.

Moreover, in the vacuum control valve 30 of this embodiment, since the breaking load generation chamber 39 which produces the breaking load by supply of a working fluid is formed in the operation part, the space occupied by the operation member 32 is made effective. The breaking load generating chamber 39 can be equipped. In addition, by providing the breaking load generating chamber inside the operating portion, it is possible to provide design freedom in the direction of reducing the diameter of the breaking load generating chamber 39. This suppresses the enlargement of the vacuum control valve resulting from the equipment of the breaking load generating chamber 39, and reduces the sliding area of the breaking load generating chamber 39, resulting in friction of the breaking load generating chamber 39. Hysteresis can be reduced.

In the vacuum control system 20 of this embodiment, when the power supply to all the electromagnetic valves is stopped, the air circuit is comprised so that the valve body 33 may move to the valve seat 42 immediately, and a breaking load may be applied. It is. As a result, it is possible to easily realize a system design in consideration of securing safety during emergency stop or power failure.

In addition, in 2nd Embodiment, although the sealing load generation chamber 39 and the interruption piston 61 are sealed with the packing, so that between the interruption load generation chamber 39 and the interruption piston 61 is sealed with a bellows ram. You may comprise. However, if the sealing load is sealed between the interruption load generating chamber 39 and the interrupting piston 61 with a packing, the configuration of the vacuum control valve can be simplified and the size can be reduced.

In addition, although V-shaped packing is used for the sealing surface which seals between the interruption load generation chamber 39 and the interruption piston 61 in 2nd Embodiment, O-ring may be sufficient, for example. This is because the O-ring also has a property that the contact surface pressure increases with the supply of the working fluid to the breaking load generating chamber 39. In the sealing between the interruption load generating chamber 39 and the interrupting piston 61, generally, a sealing part in which the surface pressure of the sealing surface is increased in accordance with the supply of the working fluid to the interruption load generating chamber 39 is used. Hysteresis can be reduced. However, when V-shaped packing is used, the dynamic frictional force at the time of non-pressurization can be made small.

In the second embodiment, the breaking load generating chamber 39 is formed inside the operating member 32, and the breaking piston 61 is disposed inside the pressing spring, but the breaking load generating chamber 39 is blocked. The piston 61 may be arranged in a reverse rotation. However, when the breaking load generating chamber 39 is formed inside the operating member 32, the breaking load generating chamber 39 can be formed using the internal space of the operating member 32, so that the vacuum control is performed. The valve can be miniaturized.

In the second embodiment, the vacuum control valve is connected with the primary port (vacuum vessel side connection port) as the low pressure side and the secondary port (vacuum pump side connection port) as the high pressure side, and the shutoff state is prevented by the breaking load against the differential pressure load. It is configured as a form to hold. However, the high pressure side and the low pressure side may be reversed. By doing in this way, it can be set as the open state against the differential pressure load of the direction which keeps a interruption | blocking state. It can also be used for pressure control of high pressure vessels as well as vacuum vessels.

(E. Modifications)

In addition, it is not limited to the description content of each embodiment mentioned above, For example, you may carry out as follows.

(a) In each of the embodiments described above, the gas discharge from the route via the gas discharge port 561 and the route via the gas discharge port 562 is performed by the single turbomolecular pump 300, for example. Each route may be equipped with a turbomolecular pump. In this way, high pump efficiency can be realized by shortening the flow path from the turbo molecular pump to the gas outlet and increasing the effective exhaust speed.

(b) In each embodiment mentioned above, although it is set as the structure using two gas discharge ports arrange | positioned at the position which pinches process reaction area | region, three or more may be sufficient, for example, and it is good to use a plurality of gas discharge ports. In addition, the configuration may be such that each of the four turbomolecular pumps is connected to each gas outlet port (the number of gas outlet ports is four) through each vacuum control valve (the number of vacuum control valves is four).

When the number of gas outlets is an odd number (for example, three), it is preferable to arrange | position at equal intervals in the annular position centering on the supply part of a process or process center Wc. The "position where the process reaction regions are sandwiched" does not have to be arranged in the horizontal plane, that is, in a plane parallel to the plane to be the process object, but may be arranged shifted in the vertical direction. Specifically, both exhaust ports may be disposed not on the side surface (first embodiment) of the vacuum vessel, but on the lower surface or the upper surface, and one side may be the lower surface and the other may be the upper surface. In addition, when the number of gas outlets is odd, the position arrange | positioned at equal intervals or nonuniform interval in the annular position centering on the supply part of a process gas is also included in the "position which pinches process reaction area | region".

(c) In each of the embodiments described above, the difference between the target value of the first slave loop and the second slave loop is used as a correction value, but for example, the target value of both the first slave loop and the second slave loop with respect to the reference value. It is good also as a structure which has a correction value. Such a structure is effective in the structure which stores a correction value in the vacuum control valve side, for example.

(d) A pressure sensor may be added to each gas discharge port so that the equipment (five sensors in total in the above-described embodiment) may be provided. In this way, a correction is obtained to obtain the conductance between the inlet of the turbomolecular pump and the gas outlet to compensate for individual differences in the exhaust measurement, or to compensate for the difference in conductance in the vacuum vessel from the process center Wc to the gas outlet. Can be realized separately. Generally, what is necessary is to compensate for the difference in conductance from a gas supply part to each exhaust part, and at least one of the individual difference of each exhaust system containing a vacuum pump and a vacuum control valve.

(e) Although each embodiment mentioned above has illustrated the mounting in the process of chemical vapor deposition (CVD), it can be used also for processes, such as an etching process and a spatter, for example. Generally, it is available for vacuum control of a vacuum vessel in which a control for maintaining a vacuum while supplying gas is required.

Each embodiment mentioned above exhibits a remarkable effect in an etching process. In the etching process, for example, there is a step of disposing a wafer W as a process target inside a vacuum vacuum chamber and exposing the process surface of the wafer W to etching gas. For example, in reactive ion etching, an etching gas is plasma-formed by discharge ionization etc. in the inside of a vacuum container, and a high frequency magnetic field is produced | generated by the cathode in which the wafer W is placed. As a result, the ion species and radical species in the plasma accelerate in the direction of the wafer W and collide with each other. As a result, sputtering by ions and a chemical reaction of the etching gas occur at the same time, so that etching at a high precision suitable for fine processing can be performed.

Such high-precision etching is also applied to MEMS (Micro Electro Mechanical Systems) to realize practical use of integrated devices such as mechanical component parts, sensors, actuators, and electronic circuits. This is because, with high precision etching, a more stable and uniform supply of etching gas is required for the wafer W.

(f) In each embodiment mentioned above, although the process reaction area | region is arrange | positioned at the mutual insertion position, what is necessary is just to arrange | position at a different position. This makes it possible to operate not only the pressure and flow rate of the process gas but also the direction of the process gas as the third operation parameter by setting the conditions of the semiconductor process, so that a new degree of freedom, which is the direction of the flow of the process gas, can be obtained. to be. The operation of the direction of the process gas may be fed back based on the state of the process, for example.

(g) In each embodiment described above, although a turbomolecular pump, a dry pump, etc. are used as a vacuum pump, the structure which uses a dry pump independently may be sufficient, for example, and what is necessary is just to use a vacuum pump generally in a broad sense. .

(h) In each of the embodiments described above, a vacuum container is used in the semiconductor manufacturing process, but other applications may be used. However, in the semiconductor manufacturing process, since the influence on the process due to the slight fluctuation of the flow of gas is large, a remarkable effect can be exerted.

Claims (1)

It is a vacuum control system which controls the vacuum pressure and flow of the process gas in the vacuum container which receives a supply of process gas from a gas supply part, and performs a process to a process target, using a vacuum pump,
And a vacuum control valve connected between each of the plurality of gas outlets disposed at different positions in the vacuum container and the vacuum pump.

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