WO2006003786A1

WO2006003786A1 - Vacuum pressure control system

Info

Publication number: WO2006003786A1
Application number: PCT/JP2005/010850
Authority: WO
Inventors: Tetsuya Toyoda
Original assignee: Ckd Corporation
Priority date: 2004-07-05
Filing date: 2005-06-14
Publication date: 2006-01-12
Also published as: CN1969241A; CN100580601C; KR101117747B1; JP4335085B2; JP2006018767A; KR20070039115A

Abstract

There is provided a vacuum pressure control system capable of quickly detecting an abnormal state in a system such as failure of a vacuum pressure sensor, leak of a reactor, and clogging of a pipe. When the valve open degree of a vacuum proportional open/close valve (16) acquired via a potentiometer (18) has reached a predetermined value X1 (YES in S22) and the vacuum pressure of a reaction chamber (10) acquired via pressure sensors (14, 15) is greater than a predetermined value X2 (NO in S24), it is judged that an abnormal state such as failure of the vacuum pressure sensor, leak of the reactor, and clogging of a pipe is caused in the system and a failure countermeasure is performed (S25). The predetermined values X1 and X2 are decided in advance by an experiment or the like so as to appropriately detect the abnormal state such as the failure of the vacuum pressure sensor, leak of the reactor, and clogging of a pipe.

Description

Specification

Vacuum pressure control system

Technical field

The present invention relates to a vacuum pressure control system used in a semiconductor manufacturing apparatus. More particularly, it relates to a vacuum pressure control system capable of detecting various abnormalities in the system.

Background art

Conventionally, for example, in a CVD apparatus of a semiconductor manufacturing apparatus, while maintaining a reduced pressure state of a reaction chamber, ie, a vacuum state, a material gas consisting of an element caustic which constitutes a thin film material is supplied onto a wafer. ing. For example, in the CVD apparatus shown in FIG. 14, the material gas is supplied from the inlet 11 of the reaction chamber 10 to the wafer in the reaction chamber 10 which is a vacuum vessel, and the vacuum pump 13 is used from the outlet 12 of the reaction chamber 10. By evacuation, the inside of the reaction chamber 10 is maintained in a vacuum state.

At this time, it is necessary to keep the vacuum pressure in the reaction chamber 10 constant, but the constant value changes depending on various conditions, low atmospheric pressure or low vacuum force close to atmospheric pressure, wide range to high vacuum Cross over the range. Therefore, it is necessary to maintain the vacuum pressure accurately and uniformly over a wide range from low vacuum close to atmospheric pressure to high vacuum. Further, in order to further improve the quality of the thin film formed on the wafer in the reaction chamber 10, the vacuum pressure in the reaction chamber 10 is set to atmospheric pressure or from the viewpoint of preventing particles from being lifted up in the reaction chamber 10. In the process of evacuating to reach the target vacuum pressure value from a low vacuum close to the atmospheric pressure, it is also necessary to slowly carry out the process of discharging the gas from the reaction chamber 10.

As a vacuum pressure control system for satisfying such a need, there is, for example, one disclosed in Japanese Patent Application Laid-Open No. 2000-163137. In this system, the vacuum volume is controlled by changing the opening degree of the vacuum proportional closing valve so that the vacuum pressure in the vacuum vessel is changed at a target vacuum pressure change rate set by an external force or previously set to a controller. While slowly advancing the process of discharging the gas from the inside of the chamber to prevent the particles from rolling up in the vacuum chamber, when discharging the gas from the vacuum chamber, The rate of change in vacuum pressure can be freely controlled!

More specifically, a vacuum pressure value changed at a target vacuum pressure change rate acquired with respect to the vacuum pressure in the reaction chamber measured by the vacuum pressure sensor is sequentially generated as an internal command, Feedback control is performed as follow-up control by setting the sequentially generated internal command as a target value of feedback control and sequentially changing the target value of feedback control. Thus, in this vacuum pressure control system, the vacuum pressure in the reaction chamber can be uniformly changed at the target vacuum pressure change rate.

Patent Document 1: Japanese Patent Application Laid-Open No. 2000-163137

Disclosure of the invention

Problem that invention tries to solve

In the conventional vacuum pressure control system described above, for example, the abnormality such as “abnormality of vacuum pressure sensor”, “leakage of reaction chamber”, “clogging of piping”, etc. After being discovered, the countermeasures will be implemented. In other words, there was a problem that the system itself could not detect abnormalities.

Therefore, the present invention has been made to solve the above-mentioned problems, and it is possible to early detect an abnormality in a system such as a vacuum pressure sensor abnormality, a reactor leak, or a piping blockage. An object is to provide a vacuum pressure control system.

Means to solve the problem

The vacuum pressure control system according to the present invention, which was made to solve the above problems, has a vacuum pressure in the vacuum vessel by changing the degree of opening on a pipe connecting the vacuum vessel and the vacuum pump. A vacuum pressure switch for measuring the vacuum pressure in the vacuum vessel, and a controller for controlling the opening degree of the vacuum proportional switch valve based on the output of the vacuum pressure sensor. In the vacuum pressure control system, the controller previously stores the relationship between the output of the vacuum pressure sensor and the degree of opening of the vacuum proportional on-off valve when the system operates normally, and the vacuum pressure sensor The relationship between the actual output of the vacuum pressure sensor and the actual opening degree of the vacuum proportional on-off valve and the stored value when performing the opening degree control of the vacuum proportional on-off valve based on the output. Was A system abnormality is detected by comparing the relationship between the output of the vacuum pressure sensor and the opening degree of the vacuum proportional on-off valve.

[0010] In this vacuum pressure control system, the controller controls the opening of the vacuum proportional on-off valve based on the output of the vacuum pressure sensor, which measures the vacuum pressure in the vacuum vessel, and the vacuum pressure sensor. Reduce the pressure (see Figure 5). Here, when the system is normal, the output of the vacuum pressure sensor and the degree of opening of the vacuum proportional on-off valve always have a fixed relationship. Therefore, in this vacuum pressure control system, the controller stores the relationship between the output of the vacuum pressure sensor and the opening degree of the vacuum proportional on-off valve in such a normal state.

[0011] Then, in the vacuum pressure control system, when an abnormality such as "abnormality in vacuum pressure sensor", "leakage in vacuum chamber", or "clogging of piping" occurs, the output of the vacuum pressure sensor described above The constant relationship in the degree of opening of the vacuum proportional on-off valve breaks down. That is, the relationship between the actual output of the vacuum pressure sensor and the actual opening of the vacuum proportional on-off valve does not match the relationship stored in the controller. Therefore, when performing the opening degree control of the vacuum proportional on-off valve based on the output of the vacuum pressure sensor, the relationship between the actual output of the vacuum pressure sensor and the actual opening degree of the vacuum proportional on-off valve; By comparing the relationship between the output of the vacuum pressure sensor stored in the controller and the degree of opening of the vacuum proportional on-off valve, it is possible to detect the above-mentioned system abnormality early.

Another aspect of the vacuum pressure control system according to the present invention, which was made to solve the above problems, is by changing the degree of opening on a pipe connecting a vacuum vessel and a vacuum pump. Based on the output of the vacuum proportional on-off valve for changing the vacuum pressure in the vacuum vessel, the vacuum pressure sensor for measuring the vacuum pressure in the vacuum vessel, and the degree of opening of the vacuum proportional on-off valve A vacuum pressure control system having a controller for controlling the opening of the vacuum proportional on-off valve when the opening ratio control of the vacuum ratio on-off valve based on the output of the vacuum pressure sensor is performed. When the output of the vacuum pressure sensor is larger than a predetermined value which is set in advance when the degree reaches a predetermined opening degree, it is determined that an abnormality occurs in the system. It is

In this vacuum pressure control system as well, the controller measures the vacuum pressure in the vacuum vessel The pressure in the vacuum chamber is reduced by controlling the opening of the vacuum proportional on-off valve based on the vacuum pressure sensor and the output of the vacuum pressure sensor (see Fig. 5). Here, when the system is normal, the output of the vacuum pressure sensor and the degree of opening of the vacuum proportional on-off valve always have a fixed relationship. Therefore, it is possible to predict the output of the vacuum pressure sensor when the degree of opening of the vacuum proportional on-off valve reaches a predetermined degree of opening set in advance.

Since the pressure in the vacuum vessel is lowered, the output of the vacuum pressure sensor is preset when the opening of the vacuum proportional on-off valve reaches the preset predetermined opening. If it is larger, it is considered that the system has an abnormality. Therefore, in this vacuum pressure control system, when performing the opening control of the vacuum proportional on-off valve based on the output of the vacuum pressure sensor, the opening degree of the vacuum proportional on-off valve has reached a predetermined opening set in advance. Sometimes, when the output of the vacuum pressure sensor is larger than a predetermined value set in advance, it is determined that an abnormality has occurred in the system. This enables early detection of system abnormalities.

Here, the predetermined opening degree of the vacuum proportional on-off valve and the predetermined opening degree of the vacuum pressure sensor, which are set in order to detect an abnormality in the system, are determined by experiments or the like that are most suitable for the abnormality to be detected. You should keep it. Therefore, the combination of the predetermined opening degree of the vacuum proportional on-off valve and the predetermined opening degree of the vacuum pressure sensor, which is set in advance, may be one set or plural sets.

In the vacuum pressure control system according to the present invention, the controller uses an operation voltage input to the vacuum proportional on-off valve instead of the degree of opening of the vacuum proportional on-off valve to detect an abnormality in the system. You can also

Alternatively, in the vacuum pressure control system according to the present invention, the controller controls the operation air pressure supplied to the vacuum proportional on-off valve instead of the degree of opening of the vacuum proportional on-off valve in order to detect an abnormality of the system. It can also be used.

[0017] In this way, even if the system is constructed with a valve that does not have a mechanism (for example, a potentiometer etc.) for detecting the opening of the vacuum proportional on-off valve, system abnormality can be detected early. Can.

[0018] In the vacuum pressure control system according to the present invention, the controller is When it is judged that an abnormality has been detected or that an abnormality has occurred in the system, it is desirable to notify that effect.

[0019] Thereby, the operator can know the abnormality of the system at an early stage, and it is also a power that can execute the countermeasure measures promptly. Note that “informative information” includes all things for hearing and visual sense etc. Informing by a single means (for example, only warning sound etc.) or in a compounding means (for example warning sound and warning display Etc.) may be offset, etc.

Further, in the vacuum pressure control system according to the present invention, when the controller detects an abnormality in the system or determines that an abnormality occurs in the system, the controller operates the system of the proportional proportional on-off valve. It is desirable to operate in the safe direction.

[0021] Here, since the safety direction of the system differs depending on the configuration of each system, the "valve opening", "opening the valve", or "to operate the vacuum proportional open / close valve in the safety direction of the system" One of "maintain the valve opening degree" corresponds. That is, in this vacuum pressure control system, the operation of the vacuum proportional on-off valve is controlled by the controller so as to enhance safety of each system at the time of abnormality. As a result, the system can be further enhanced in safety because measures can be taken automatically.

Effect of the invention

[0022] According to the vacuum pressure control system of the present invention, by the above-described means, it is possible to early detect abnormalities in the system such as vacuum pressure sensor abnormalities, reactor leaks, and piping clogs.

Brief description of the drawings

FIG. 1 is a block diagram schematically showing a vacuum pressure control system according to an embodiment.

FIG. 2 is a cross-sectional view when the vacuum proportional on-off valve is in a closed state.

FIG. 3 is a cross-sectional view of the vacuum proportional on-off valve in an open state.

FIG. 4 is a block diagram schematically showing a vacuum pressure control system according to an embodiment.

[Fig. 5] In the vacuum pressure change speed control mode, the conductance (valve opening) of the vacuum proportional on-off valve is changed to reduce the pressure in the reaction chamber at a set constant speed and to show the behavior FIG.

FIG. 6 is a flow chart showing processing contents of a vacuum pressure change rate control mode. [Fig. 7] Fig. 7 is a flowchart showing the contents of preparation time processing of vacuum pressure change rate control mode.

[Fig. 8] Fig. 8 is a flowchart showing the contents of execution time processing in the vacuum pressure change rate control mode.

FIG. 9 is a view showing an example of the pressure change of the reaction chamber and the change of the valve opening degree of the vacuum proportional on-off valve in the vacuum pressure change speed control mode at the normal time.

[FIG. 10] A diagram showing an input signal in valve lift amount ramp-up processing.

FIG. 11 is a view showing an example of a change in pressure of the reaction chamber and a change in valve opening degree of the vacuum proportional on-off valve when abnormality is detected and abnormal processing is performed.

FIG. 12 is a view showing an example of a pressure change of the reaction chamber and a change of the valve opening degree of the vacuum proportional on-off valve when abnormality is detected and abnormal processing is performed.

FIG. 13 is a view showing an example of a change in pressure in a reaction chamber and a change in valve opening of a vacuum proportional on-off valve when an abnormality is detected and an abnormal process is performed.

FIG. 14 is a view showing an outline of a CVD apparatus and its exhaust system.

Explanation of sign

[0024] 10 CVD chamber reaction chamber

14, 15 Vacuum pressure sensor

16 Vacuum proportional on-off valve

18 potentiometer

20 controller

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the most preferable embodiment of the vacuum pressure control system of the present invention will be described in detail based on the drawings. Therefore, FIG. 1 shows a block diagram of a vacuum pressure control system according to the present embodiment, as compared with FIG. 14 shown in the column of the prior art. The vacuum pressure control system according to the present embodiment includes a controller 20, an air pressure control unit 30, a vacuum proportional on-off valve 16 which is an operation unit 40, and vacuum pressure sensors 14 and 15 which are a detection unit 60.

The controller 20 includes an interface circuit 21, a vacuum pressure control circuit 22, and a sequence control circuit 23. An interface circuit 21 is provided on the front panel of the controller 20. The signal from the field input through the tongue and the signal from the remote input through the connector on the back panel of the controller 20 are converted into signals suitable for the vacuum pressure control circuit 22, the sequence control circuit 23, and the like. Further, as described later, the controller 20 stores a constant relationship between the output of the vacuum pressure sensor and the opening degree of the vacuum proportional on-off valve at normal times, and this constant relationship and the actual condition of the vacuum pressure sensor. It compares the output with the actual opening degree of the vacuum proportional on / off valve to detect (determine) an abnormality in the system.

The vacuum pressure control circuit 22 is a circuit that performs feedback control with respect to the vacuum pressure in the reaction chamber 10 of FIG. 14 by PID control. The sequence control circuit 23 is predetermined for the drive coil SV1 of the first solenoid valve 34 and the drive coil SV2 of the second solenoid valve 35 in the air pressure control unit 30 according to the operation mode given by the interface circuit 21. It is a circuit that operates.

The pneumatic control unit 30 includes a position control circuit 31, a pulse drive circuit 32, a time opening / closing operation valve 33, a first solenoid valve 34, and a second solenoid valve 35. Position control circuit 31 has a valve opening degree command value given from vacuum pressure control circuit 22 and a valve opening degree measurement value given from potentiometer 18 provided on vacuum proportional on / off valve 16 through amplifier 19. And the position of the vacuum proportional on-off valve 16 is controlled. The pulse drive circuit 32 transmits a pulse signal to the time switching valve 33 based on the control signal from the position control circuit 31.

The time opening / closing operation valve 33 incorporates an air supply side proportional valve and an exhaust side proportional valve (not shown), and according to the pulse signal from the pulse drive circuit 32, the air supply side proportional valve and the exhaust side The proportional valve is operated to open and close for a time, and the air pressure in the pneumatic cylinder 41 (see FIGS. 2 and 3 described later) of the vacuum proportional on-off valve 16 via the second solenoid valve 35 and the first solenoid valve 34. To adjust the

Referring to FIG. 14, the vacuum proportional on-off valve 16 which is the operation unit 40 changes the conductance of the exhaust system from the reaction chamber 10 to the vacuum pump 13. Figures 2 and 3 show the cross sections of the vacuum ratio example on-off valve 16. As shown in the figure, a piston rod 43 is provided at the center thereof. The piston 44 is fixed inside the pneumatic cylinder 41 which is an upper portion of the vacuum proportional on-off valve 16 with respect to the piston rod 43, and a poppet valve in a bellows type poppet valve 42 which is a lower portion of the vacuum proportional on-off valve 16. Body 45 is fixed. Therefore, it is empty The poppet valve body 45 can be moved by the pneumatic cylinder 41.

In the vacuum proportional on-off valve 16, when the compressed air is not supplied into the pneumatic cylinder 41 through the supply port 18A, and the inside of the pneumatic cylinder 41 communicates with the exhaust line through the exhaust port 18B, the pneumatic cylinder is a pneumatic cylinder. Since the downward biasing force by the return panel 46 in 41 acts on the piston 44, as shown in FIG. 2, the poppet valve body 45 is in close contact with the valve seat 47, and the vacuum proportional on / off valve 16 is shut off.

On the other hand, when compressed air is supplied into the pneumatic cylinder 41 through the air supply port 18 A, downward biasing force by the return panel 46 in the pneumatic cylinder 41 and upward pressure by the compressed air in the pneumatic cylinder 41. Since the pressure and the pressure simultaneously act on the piston 44, according to the balance, as shown in FIG. 3, the poppet valve body 45 is separated from the valve seat 47, and the vacuum proportional on / off valve 16 is in an open state.

Therefore, the distance by which the poppet valve body 45 is separated from the valve seat 47 can be operated by supply and exhaust of compressed air to the pneumatic cylinder 41 as the lift amount of the valve. The distance at which the poppet valve body 45 is separated from the valve seat 47 is measured by the potentiometer 18 via the slide lever 48 connected to the piston 44 as the valve lift amount. It corresponds to an opening degree of 16.

The vacuum pressure sensors 14 and 15, which are detection units, are capacitance manometers that measure the vacuum pressure in the reaction chamber 10 of FIG. Here, two capacitance manometers are used depending on the range of vacuum pressure to be measured.

In the vacuum pressure control system according to the present embodiment having such a configuration, when the forced close mode (CLOSE) is selected by the controller 20 as the operation mode, the sequence control circuit 23 controls the first solenoid valve. 34 and the second solenoid valve 35 are operated as shown in FIG. As a result, compressed air is not supplied into the pneumatic cylinder 41 and the inside of the pneumatic cylinder 41 communicates with the exhaust line, so the air pressure inside the pneumatic cylinder 41 becomes atmospheric pressure, and the vacuum proportional opening and closing valve 16 is shut off. It becomes.

Further, when the vacuum pressure control mode (PRESS) is selected by the controller 20 as the operation mode, the sequence control circuit 23 operates the first solenoid valve 34 so that the time opening / closing operation valve 33 and the pneumatic cylinder 41 Communicate with Thus, the vacuum proportional opening and closing The air pressure in the pneumatic cylinder 41 of the valve 16 is adjusted, and the valve lift amount force can be operated by the pneumatic cylinder 41.

Further, at this time, the vacuum pressure control circuit 22 starts feedback control in which the target vacuum pressure value instructed by the on-site input or remote input is set as the target value. That is, in FIG. 14, the vacuum pressure value in the reaction chamber 10 is measured by the vacuum pressure sensors 14 and 15, and the valve of the vacuum proportional on-off valve 16 is adjusted according to the difference (control deviation) from the target vacuum pressure value. By operating the lift amount and changing the conductance of the exhaust system, the vacuum pressure in the reaction chamber 10 is kept constant at the target vacuum pressure value.

Further, in the vacuum pressure control circuit 22, when the control deviation of the feedback control is large, the operation amount of the feedback control is maximized, so that the speed response of the feedback control is sufficiently secured. On the other hand, when the control deviation of the feedback control is small, the vacuum pressure in the reaction chamber 10 can be maintained in a stable state because the time transition is made stepwise to the previously adjusted time constant.

Specifically, as shown in the block diagram of FIG. 4, the value obtained by adjusting the vacuum pressure value in the reaction chamber 10 measured by the vacuum pressure sensors 14 and 15 by the proportional differentiation circuits 105 and 106 is a field input. Alternatively, after being compared with the target vacuum pressure value indicated by the remote input, it is input to the proportional derivative integration circuits 102, 103. After that, the integration circuit 104 connected in series outputs a voltage in the range of 0 to 5 V in order to output it to the position control circuit 31. The time constant of the integration circuit 104 is determined by the integration time adjustment circuit 101.

When the measured values of the vacuum pressure sensors 14 and 15 are apart from the target vacuum pressure value, the internal arithmetic circuit operates so as to minimize the integration time of the integration circuit. Thus, the integration circuit 104 functions as an amplification circuit having an almost infinite gain.

[0041] That is,

(Vacuum pressure sensor 14, 15 measured values)> (Target vacuum pressure value)

In this case, 5 V, which is the maximum value of the integration circuit 104, is output to the position control circuit 31. As a result, the vacuum proportional on-off valve 16 operates in the direction to open rapidly. on the other hand,

(Vacuum pressure sensors 14, 15 measured values) <(Target vacuum pressure value)

In this case, OV, which is the minimum value of integration circuit 104, is output to position control circuit 31. Be As a result, the vacuum proportional on / off valve 16 operates in the direction of rapid closing.

[0042] By these operations, the valve opening degree of the vacuum proportional on-off valve 16 can be reached in the shortest time to near the position for achieving the target vacuum pressure value. After that, the integration time adjustment circuit 101 determined to have reached near the position for achieving the target vacuum pressure value holds the vacuum pressure in a stable state at that position. Perform an operation to shift to the time constant in stages.

Furthermore, in the vacuum pressure control system according to the present embodiment, when the vacuum pressure change rate control mode (SVAC) is selected by the controller 20 as the operation mode, the vacuum pressure in the reaction chamber 10 is the target vacuum pressure. It is possible to control even the rate of change in vacuum pressure in the reaction chamber 10 when

As described above, in the vacuum pressure change rate control mode (SVAC), as shown in FIG. 5, the conductance (valve opening) of the vacuum proportional on-off valve 16 is changed by feedback control. The pressure in the reaction chamber 10 is reduced at a set constant speed. For this reason, in the vacuum pressure control system, when an abnormality such as “abnormality of the vacuum pressure sensor 14, 15”, “leakage of the reaction chamber 10”, or “clogging of piping” has occurred, the vacuum pressure is At a certain point in the change speed control mode (SVAC), the relationship between “valve opening of vacuum proportional on-off valve 16” and “value of vacuum pressure sensor 14, 15” does not become as shown in FIG. Then, using this phenomenon, the vacuum pressure control system according to the present embodiment detects the above-mentioned abnormality.

The operation of the vacuum pressure control system according to the present embodiment will be described with reference to FIGS. 6 to 9. FIG. 6 is a flow chart for the vacuum pressure change rate control mode (SVAC). FIG. 7 is a flow chart of the preparation time of the vacuum pressure change rate control mode (S VAC). FIG. 8 is a flow chart of the execution time of the vacuum pressure change rate control mode (SVAC). FIG. 9 is a view showing an example of the pressure change of the reaction chamber and the change of the valve opening degree of the vacuum proportional on-off valve 16 in the vacuum pressure change rate control mode (SVAC) in the normal state. In the vacuum pressure change speed control mode (SVAC), the forced close mode (CLOSE) force shall be transferred. The vacuum pressure change rate control mode (SVAC) executes two subroutines, that is, preparation time processing and execution time processing, as shown in FIG. Then, when the vacuum pressure change rate control mode (SVAC) is selected by the controller 20, first, preparation time processing is executed.

Then, first, the current vacuum pressure in the reaction chamber 10 is obtained via the vacuum pressure sensors 14 and 15 (Sl). Here, since the current vacuum pressure in the reaction chamber 10 is the atmospheric pressure VO (see FIG. 9), the atmospheric pressure VO is obtained.

Next, the valve opening degree of the vacuum proportional on-off valve 16 is acquired via the potentiometer 18 (S 2). Then, it is determined whether the acquired valve opening degree has reached the set value XI (S3). At this time, if the valve opening has reached the set value XI (S3: YES), the current vacuum pressure in the reaction chamber 10 is acquired via the vacuum pressure sensors 14 and 15 (S4). Then, it is determined whether the obtained vacuum pressure in the reaction chamber 10 is equal to or less than the set value X2 (S5). At this time, if the current vacuum pressure in the reaction chamber 10 is larger than the set value X2 (S5: NO), it is determined that an abnormality has occurred, and the vacuum pressure change rate control mode (SV AC) is selected. The process is ended and an abnormal process is performed (S6).

Here, the set value XI is a threshold value for detecting (judging) an abnormality of the system. That is, when the valve opening degree of the vacuum proportional on-off valve 16 reaches the set value XI, the system abnormality detection processing is performed. Further, the set value X2 is a threshold value for determining whether or not the system has an abnormality when the abnormality detection process is performed. That is, when the abnormality detection process is performed and the current vacuum pressure in the reaction chamber 10 is larger than the set value X2, it is determined that an abnormality occurs in the system.

On the other hand, when the valve opening degree reaches the set value XI, etc. (S3: NO), the present vacuum pressure in the reaction chamber 10 is less than the set value X2 (S5). : YES), Lift amount of valve Perform ramp-up processing (S7). Here, since the forced closing mode (CLOSE) force is being transferred, when the vacuum pressure change rate control mode (SVAC) is selected, the vacuum proportional on-off valve 16 is in the closed state. Therefore, as shown in FIG. 10, the bias control circuit 110 outputs a command voltage to the position control circuit 31 so that the lift amount of the vacuum proportional on-off valve 16 changes in a ramp function, and the position control circuit 31 Control signal to pulse drive circuit 32 Issue the issue (see Figure 4). Here, as an example, the time tl is set to 10 sec, and the valve lift value L1 is set to 0.1266 mm.

Then, it is determined whether or not lOsec, which is time tl, has elapsed (S8). If it is determined that the time tl, which is 10 seconds ec, has elapsed (S8: YES), the force for proceeding to S11 is determined that the time tl, lOsec has not elapsed (S3: NO), the process proceeds to S9. The current vacuum pressure in the reaction chamber 10 is obtained via the vacuum pressure sensors 14, 15. Thereafter, with respect to the vacuum pressure in the reaction chamber 10, it is determined whether or not there is a slight pressure drop (S10). If it is determined that there is no slight pressure drop (S10: NO), the process returns to S2 to repeat the above-described process. Here, let a slight pressure drop be a pressure drop of 266 Pa or more.

On the other hand, when it is determined that there is a pressure drop of 266 Pa or more (S10: YES), and when it is determined that lOsec which is time tl has elapsed (S3: YES), the process proceeds to S11. In S11, a target value of feedback control for the vacuum pressure in the reaction chamber 10 is set to a value VI (see FIG. 9) obtained by subtracting 266 Pa from the current vacuum pressure.

Thereafter, the valve opening degree of the vacuum proportional on-off valve 16 is acquired via the potentiometer 18 (see FIG.

512). Then, it is determined whether the acquired degree of opening has reached the set value XI (

513). At this time, if the valve opening has reached the set value XI (S13: YES), the current vacuum pressure in the reaction chamber 10 is acquired via the vacuum pressure sensors 14, 15 (S14) . Then, it is determined whether or not the acquired current vacuum pressure in the reaction chamber 10 is equal to or less than the set value X2 (S15). At this time, if the current vacuum pressure in the reaction chamber 10 is larger than the set value X2 (S15: NO), it is judged that an abnormality has occurred, and the vacuum pressure change rate control mode (SVAC) is ended. An abnormal state process is performed (S16).

On the other hand, when the valve opening does not reach the set value XI (S13: NO), or when the current vacuum pressure in the reaction chamber 10 is less than the set value X2 (S15: YES), For the vacuum pressure in the reaction chamber 10, the feedback control with the target value of the current vacuum pressure minus 266Pa as VI (see Fig. 9), a predetermined time (here, lOsec) elapses It performs as fixed value control (S17). Then, when feedback control is started and it is determined that lOsec has elapsed (S18: YES), the processing shifts to execution time processing.

Note that the abnormal processing in S6 and S16 indicates that an abnormality has occurred in the system. Informing and operating the vacuum proportional control valve 16 in the safe direction. In the present embodiment, depending on the force system for operating the vacuum proportional control valve 16 in the closing direction, the valve may be operated in the opening direction or the current valve opening degree may be maintained. This is because the safety direction differs depending on the system. Therefore, in the abnormal state processing, it may be set so that the valve operation suitable for each system can be performed. In addition, “informative information” includes all things for hearing and visual sense etc. Informing by a single means (for example, only warning sound etc.) or in a compounding means (for example warning sound and warning etc. It may be offset, etc.).

In the execution time process, first, the valve opening degree of the vacuum proportional on-off valve 16 is acquired via the potentiometer 18 (S21). Then, it is determined whether the acquired valve opening has reached the set value XI (S22). At this time, if the valve opening has reached the set value XI (S22: YES), the current vacuum pressure in the reaction chamber 10 is acquired via the vacuum pressure sensors 14, 15 (S23). Then, it is determined whether the acquired current vacuum pressure in the reaction chamber 10 is less than or equal to the set value X2 (S24). At this time, if the current vacuum pressure in the reaction chamber 10 is larger than the set value X2 (S24: NO), it is determined that an abnormality has occurred, and the vacuum pressure change speed control mode (SVAC) is set. The process is ended and an abnormal process is performed (S25).

On the other hand, when the valve opening does not reach the set value XI (S22: NO), or when the current vacuum pressure in the reaction chamber 10 is less than the set value X2 (S24: YES), The target vacuum pressure value instructed by the site input or remote input is acquired (S26). Also, the current vacuum pressure in the reaction chamber 10 is obtained via the vacuum pressure sensors 14 and 15 (S27). Then, it is determined whether or not the current vacuum pressure in the reaction chamber 10 has reached the target vacuum pressure value (S28). If the current vacuum pressure in the reaction chamber 10 has not reached the target vacuum pressure value (S28: NO), the target vacuum pressure change rate indicated by the on-site input or remote input is acquired (S29).

Further, the current vacuum pressure value in the reaction chamber 10 is acquired via the vacuum pressure sensors 14 and 15 (S30). Then, the controller 20 generates, as an internal command, the vacuum pressure value changed at the target vacuum pressure change rate acquired in S29 with respect to the current vacuum pressure value of the reaction chamber 10 acquired in S30. Then, the internal command is set as the target value of feedback control, and the target value of feedback control is changed (S31). Thereafter, feedback control is performed (S32) Specifically, as shown in the block diagram of FIG. 4, the target vacuum pressure value and the vacuum pressure change speed instructed by the on-site input or remote input are 0 to 5 V by the interface circuit 21 (see FIG. 1). , And is input to the internal command generation circuit 111. The internal command generation circuit 111 subtracts a predetermined vacuum pressure value from the current vacuum pressure value of the reaction chamber 10 according to the magnitude of the vacuum pressure change rate, and outputs that value as a target value for feedback control. .

On the other hand, when the current vacuum pressure in reaction chamber 10 has reached the target vacuum pressure value,

(S28: YES) The target vacuum pressure value acquired in S26 is set as the target value of feedback control. Thereafter, feedback control is performed (S32).

[0061] The feedback control of S32 is continued as long as the operation mode is not changed from the vacuum pressure change rate control mode (SVAC) !.

Here, the case where an abnormality is detected and an abnormality process is performed will be described with reference to specific examples shown in FIGS. 11 to 13. FIG. 11 is a view showing a state in which an abnormality occurs in the vacuum pressure sensors 14 and 15. FIG. 12 is a view showing a state of the reaction chamber 10 at the time of leak. FIG. 13 is a diagram showing a state in which the pipe is clogged.

First, as shown in FIG. 11, when the pressure in the reaction chamber 10 does not decrease due to the occurrence of an abnormality in the vacuum pressure sensors 14 and 15, the valve opening degree of the vacuum proportional on-off valve 16 at time t2 Reaches the set value XI. At this time, the vacuum pressure of the reaction chamber 10 is not less than the set value X2

In other words, 10 seconds after the start of the vacuum pressure change rate control mode (SVAC) at time t2, a system error occurs in the processing of S3 to S6 in FIG. 7! It is judged that /. Then, an abnormal processing is performed to close the vacuum proportional on-off valve 16. On the other hand, when time t2 has elapsed for 10 seconds from the start of the vacuum pressure change rate control mode (SVAC), it is determined that an abnormality has occurred in the system in the process of S13 to S16 in FIG. Then, an abnormal processing is performed to close the vacuum proportional on-off valve 16.

Next, a leak occurs in the reaction chamber 10, and as shown in FIG. 12, when the pressure does not fall from the middle of the pressure drop in the reaction chamber 10, the vacuum proportional on-off valve 16 is selected at time t3. The valve of The opening reaches the set value XI. At this time, the vacuum pressure of the reaction chamber 10 does not become less than the set value X2.

That is, when 10 seconds have not elapsed from the start of the pressure drop in the reaction chamber 10 at time t3, it is determined that an abnormality has occurred in the system in the processes of S13 to S16 in FIG. Then, an abnormal processing is performed to close the vacuum proportional on-off valve 16. On the other hand, if 10 seconds have elapsed from the start of the pressure drop in the reaction chamber 10 at time t3, it is determined that an abnormality has occurred in the system in the process of S22 to S25 in FIG. Then, an abnormal processing is performed to close the vacuum proportional on-off valve 16.

Finally, if the piping is clogged and the pressure does not fall during the pressure drop of the reaction chamber 10 as shown in FIG. 12, the valve opening of the vacuum proportional on-off valve 16 is set to the set value at time t4. Reach XI. At this time, the vacuum pressure of the reaction chamber 10 is not less than the set value X2.

That is, when 10 seconds have not elapsed from the start of the pressure drop in the reaction chamber 10 at time t4, it is determined that an abnormality has occurred in the system in the processes of S13 to S16 in FIG. Then, an abnormal processing is performed to close the vacuum proportional on-off valve 16. On the other hand, if 10 seconds have elapsed from the start of the pressure drop in the reaction chamber 10 at time t3, it is determined that an abnormality has occurred in the system in the process of S22 to S25 in FIG. Then, an abnormal processing is performed to close the vacuum proportional on-off valve 16.

On the other hand, when normal, as shown in FIG. 9, the valve opening degree of the vacuum proportional on-off valve 16 reaches the set value XI at time t, but the vacuum pressure of the reaction chamber 10 at that time is from the set value X2. Because it is also small, it is judged that the system has an abnormality.

As described above, in the vacuum pressure control system according to the present embodiment, it is possible to rapidly detect an abnormality in the system, such as leaks in the vacuum pressure sensors 14 and 15, the reaction chamber 10, or clogging of piping. Then, when an abnormality is detected, the vacuum proportional on-off valve 16 is closed while notifying that effect. Therefore, it is possible to construct a very safe vacuum pressure control system.

The set values XI and X2 set to detect each of the above-mentioned abnormalities may be obtained in advance by experiments or the like so that the respective abnormalities can be detected appropriately.

Here, a mechanism for detecting the degree of valve opening like the vacuum proportional on-off valve 16 (potentiometer 1 When using a valve that is not equipped with 8), use the operating voltage supplied to the valve or the operating air pressure supplied to the valve instead of using the valve opening to detect an abnormality in the system. Just do it. As a result, even if the system is constructed with a valve that does not have a mechanism for detecting the degree of opening of the valve, it is possible to detect system abnormality early.

As described above, in the vacuum pressure control system according to the present embodiment, as described in detail above, when controller 20 reaches the set value XI that is set in advance, the valve opening degree of vacuum proportional on-off valve 16 If the vacuum pressure in the reaction chamber 10 is larger than the preset set value X2, it is determined that an abnormality has occurred in the system. The set values XI and X2 are obtained in advance by experiments so that each abnormality can be detected properly. Therefore, according to the vacuum pressure control system according to the present embodiment, it is possible to rapidly detect an abnormality in the system such as leaks of the vacuum pressure sensors 14 and 15, the reaction chamber 10, or clogging of piping. Then, when an abnormality is detected, the fact is notified and the vacuum ratio on / off valve 16 is closed. Therefore, a very safe vacuum pressure control system can be built.

The above-described embodiment is merely an example, and it is needless to say that various improvements and modifications can be made without departing from the scope of the present invention without limiting the present invention in any way. . For example, although the present invention is applied to the reaction chamber 10 of the CVD apparatus in the above-described embodiment, the present invention can be applied to the vacuum containers of other semiconductor production lines. It is possible.

Claims

The scope of the claims

[1] A vacuum proportional on-off valve for changing the vacuum pressure in the vacuum vessel by changing the degree of opening on a pipe connecting the vacuum vessel and the vacuum pump, and measuring the vacuum pressure in the vacuum vessel A vacuum pressure control system comprising: a vacuum pressure sensor; and a controller for controlling an opening of the proportional open / close valve based on an output of the vacuum pressure sensor;

The controller

The relationship between the output of the vacuum pressure sensor and the opening degree of the vacuum proportional opening / closing valve when the system normally operates is stored in advance,

When performing the opening control of the vacuum proportional on-off valve based on the output of the vacuum pressure sensor, the relationship between the actual output of the vacuum pressure sensor and the actual opening of the vacuum proportional on-off valve and the memory A vacuum pressure control system, which detects a system abnormality by comparing the relationship between the output of the vacuum pressure sensor and the opening degree of the vacuum proportional on-off valve.

[2] A vacuum proportional on-off valve for changing the vacuum pressure in the vacuum vessel by changing the degree of opening on a pipe connecting the vacuum vessel and the vacuum pump, and measuring the vacuum pressure in the vacuum vessel A vacuum pressure control system comprising: a vacuum pressure sensor; and a controller for controlling an opening of the proportional open / close valve based on an output of the vacuum pressure sensor;

When the controller is performing the opening control of the vacuum proportional on-off valve based on the output of the vacuum pressure sensor, when the opening degree of the vacuum proportional on-off valve reaches a preset predetermined opening degree A vacuum pressure control system characterized in that when the output of the vacuum pressure sensor is larger than a predetermined value set in advance, it is determined that an abnormality has occurred in the system.

[3] In the vacuum pressure control system according to claim 1 or 2,

A vacuum pressure control system, wherein the controller uses an operation voltage input to the vacuum proportional on-off valve instead of the opening degree of the vacuum proportional on-off valve in order to detect an abnormality in the system.

[4] In the vacuum pressure control system according to claim 1 or claim 2, in order to detect an abnormality in the system, the controller performs the vacuum proportional opening and closing instead of the opening of the vacuum proportional opening and closing valve. A vacuum pressure control system characterized by using an operating air pressure supplied to a valve.

[5] In the vacuum pressure control system according to any one of claims 1 to 4, when the controller detects an abnormality in the system or determines that an abnormality has occurred in the system, Vacuum pressure control system characterized by notifying.

[6] The vacuum pressure control system according to any one of claims 1 to 5, wherein the controller detects an abnormality of the system or determines that an abnormality has occurred in the system. A vacuum pressure control system characterized by operating a proportional on-off valve in a safe direction of the system.