JP2007214406A - Semiconductor manufacturing apparatus mounted with mass-flow-rate controller having flow-rate testing function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide such a semiconductor manufacturing apparatus that mass-flow-rate testing operations are performed automatically in the semiconductor manufacturing apparatus having mass-flow-rate controllers. <P>SOLUTION: The semiconductor manufacturing apparatus 1 has mass-flow-rate controllers 40 and opening/closing valves V in its fluid feeding passage, and has an exhausting device P at its end. Further, the semiconductor apparatus 1 has a controller C for controlling the operations of the mass-flow-rate controllers 40, the opening/closing valves V, and the exhausting device P, etc. Moreover, the mass-flow-rate controller 40 has the testing function for its flow-rate control. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a semiconductor manufacturing apparatus equipped with a mass flow control device that measures a mass flow rate of a fluid having a relatively small flow rate such as a gas, and more particularly, to a mass flow control device capable of verifying accuracy of mass flow control. The present invention relates to a mounted semiconductor manufacturing apparatus.

In general, in order to manufacture a semiconductor product such as a semiconductor integrated circuit, for example, CVD film formation and etching operations are repeatedly performed on a semiconductor wafer or the like in various semiconductor manufacturing apparatuses. For example, a mass flow controller such as a mass flow controller is used because it is necessary to control the supply amount of the gas accurately.
Therefore, in this type of mass flow control device, the flow (hereinafter referred to as “actual flow”) that actually flows through the flow control valve with respect to the mass flow indicated by the flow setting signal (hereinafter also simply referred to as “flow”). (Also referred to as “Also”), it is necessary to match with high accuracy. However, if the supply gas pressure changes or the device itself changes over time, it will flow even if the same valve drive voltage as the original delivery is applied. There are cases where the actual flow rate of the gas is slightly different.

  In particular, corrosive gases such as silane and phosphine used for process gas may cause the generated solids to be deposited inside the semiconductor manufacturing equipment including the gas piping line due to the characteristics. It may cause volume changes at various locations within the manufacturing apparatus. For example, in a system including a prior art test tank, the shape of the tank is approximately 10φ × 28 mm, and the volume change rate is only 4.6% assuming that a 0.1 mm product adheres to the entire processing chamber surface. Absent. On the other hand, the product adhesion to the narrow pipe part (sensor pipe) of the mass flow controller is determined by the ratio of the cross-sectional area of the pipe before and after the adhesion. The change in the cross-sectional area due to adhesion is 64%, and the performance of the mass flow rate control device that should strictly control the flow rate deteriorates, and proper gas supply cannot be performed.

  For this reason, in order to verify whether or not the mass flow controller can control the flow rate as designed, flow rate verification is performed periodically or irregularly. An example of this flow rate verification is to provide a separate verification tank with a known capacity in the gas pipeline, stop the gas supply from a state where a constant gas flow rate has been stably flowed, and then put it into the verification tank. Whether the accumulated gas flows out or not is compared with a reference pressure change at the time of shipment or the like to determine whether the gas is right or wrong.

For example, Patent Document 1 discloses a plurality of process gas lines, a measurement gas line branched from the process gas line, a first pressure regulator, a shut-off valve, a pressure sensor, There is disclosed a flow rate verification system in which two pressure regulators are sequentially piped, and a mass flow rate controller is validated by measuring a pressure drop between the shutoff valve and the second pressure regulator with a pressure sensor.
Patent Document 2 discloses a calibration method in which a gas flow rate is measured by a flow meter and a sensor unit of a mass flow controller, and the detection characteristics of the mass flow controller are corrected based on the obtained detection characteristics.
Further, Patent Document 3 proposes a semiconductor manufacturing apparatus having a flow rate verification gas source, a verification mass flow controller, and a piping system that leads to an exhaust device via an on-off valve, in addition to the process gas system. .

JP 11-223538 A JP 2004-20306 A JP-A-6-53103

However, according to the flow rate verification system disclosed in Patent Document 1, a branched measurement gas line must be separately installed, and a dedicated personal computer system for operating and verifying the measurement gas line is required. There is a problem that. In Patent Document 2, the installation of piping is minimal, but the calibration flow meter itself needs to be separately verified, and at the time of verification, pressure regulators are installed upstream and downstream of the mass flow controller. Alternatively, there is a problem that the valves need to be operated so as to be suitable for the test state. In addition, according to the semiconductor manufacturing apparatus disclosed in Patent Document 3, a branched flow calibration gas line must be separately installed, and the verification apparatus is configured with a mass flow controller. The apparatus and the apparatus to be tested are flow rate tests using the same principle, and similarly, there is a problem that the calibration with the test apparatus to which the generated solid matter is attached has a large error.
Furthermore, it is necessary to check the state of the semiconductor manufacturing equipment at the end when the mass flow control device is verified, and this confirmation work, line stop judgment, and operation of valves, etc. are only complicated. In addition, there is a problem that a semiconductor manufacturing apparatus using gas must be stopped for a long time.
Focusing on the above problems, it was created to effectively solve this problem, and the object of the present invention is to eliminate the need for special piping laying and to automatically mass without complicated work. An object of the present invention is to provide a semiconductor manufacturing apparatus equipped with a mass flow rate control device with a flow rate verification function for performing verification and flow rate calibration of the flow rate control device.

In order to achieve the above object, the present invention provides a semiconductor manufacturing apparatus having a mass flow control device and an on-off valve in a fluid supply path, and having an exhaust device at a terminal, wherein the semiconductor manufacturing apparatus has the mass flow rate. A control device for controlling the operation of the control device, the on-off valve, the exhaust device, etc., and the mass flow control device is a mass flow control device having a flow control verification function and / or a flow rate calibration function. It is a certain semiconductor manufacturing apparatus.
In the present invention, the control device outputs a predetermined operation signal to the on-off valve and the exhaust device at the time of flow rate verification, and outputs a flow rate verification operation signal to the mass flow rate control device simultaneously or afterwards. It is a manufacturing device.
Because of this configuration, it is not necessary to install extra piping lines in the semiconductor manufacturing equipment, and the gas supply line system on-off valves and exhaust devices are installed from the control equipment of the semiconductor manufacturing equipment at an appropriate time in semiconductor manufacturing. Since it is possible to issue an instruction signal in a unified manner so that the mass flow control device is in a state necessary for verification, and to issue a verification function operation command for the mass flow control device with flow verification function, the entire semiconductor manufacturing apparatus can be completed in a short time. Test and calibrate to the optimal state.

Further, in the present invention, the mass flow rate control device detects a mass flow rate of the fluid flowing in the flow path and outputs a flow rate signal to the flow path of the fluid, and opens the valve by a valve drive signal. A flow rate control valve mechanism for controlling the mass flow rate by changing the degree of flow, and a mass flow rate provided with control means for controlling the flow rate control valve mechanism based on a flow rate setting signal and the flow rate signal input from the outside A control device,
The flow path is provided with a verification valve section for opening and closing the flow path, a verification tank section having a predetermined capacity, and a pressure detection means for detecting a pressure of the fluid and outputting a pressure detection signal, respectively. It is desirable that the mass flow rate control device is configured to include verification control means for controlling the mass flow rate verification operation using the verification valve, the verification tank unit, and the pressure detection means.
In this way, after the verification valve unit and the verification tank unit are provided in the device itself and the verification valve unit is closed and the fluid supply is stopped, the pressure change of the fluid flowing out from the verification tank unit is detected. At the same time, by comparing this pressure change with, for example, a reference reference pressure change, it is possible to test whether the mass flow rate of the flowing fluid can be accurately controlled. Alternatively, the ratio between the pressure drop amount of the fluid flowing out from the verification tank and the integrated value of the output of the mass flow rate detecting means is the ratio of the reference pressure drop amount and the integrated value of the output of the mass flow rate detecting means. A test can be performed by comparison.

  The mass flow control device may be a mass flow control device in which a zero point measurement valve unit that opens and closes the outlet side of the flow channel when the zero point is measured is provided in the flow channel.

According to the semiconductor manufacturing apparatus equipped with the mass flow controller with a flow rate verification function of the present invention, the following excellent operational effects can be exhibited.
The mass flow control device itself is provided with a verification valve section and a verification tank section, and after the verification valve section is closed and the supply of fluid is stopped, the pressure change of the fluid flowing out from the verification tank section is detected. In addition, a mass flow controller with a flow rate verification function that can verify whether the mass flow rate of the flowing fluid can be accurately controlled by comparing this pressure change with, for example, a reference pressure change as a reference is mounted. Since it is a semiconductor manufacturing device, an instruction signal is sent from the control device of the semiconductor manufacturing device at an appropriate time in the semiconductor manufacturing so that the gas supply line system on-off valve and exhaust device are in a state necessary for the verification of the mass flow control device. Since it is possible to issue a verification function operation command for a mass flow controller with a flow rate verification function in a centralized manner, the entire semiconductor manufacturing equipment is verified in an optimal state in a short time. Door can be.

An embodiment of a semiconductor manufacturing apparatus equipped with a mass flow controller with a flow rate verification function according to the present invention will be described below with reference to FIG. In FIG. 1, the process gas is adjusted to an appropriate pressure from the process gas sources L1 and L2 by the pressure control devices R1 and R2, and the mass flow control device 40- with a flow rate verification function is supplied via the on-off valves V1 and V4. 1 and 40-2 to the inlet, and in a state where the flow rate is controlled, from the outlet of the mass flow rate control devices 40-1 and 40-2 with flow rate verification function via the on-off valves V2, V5 and V10, the processing chamber D. The outlet of the processing chamber D reaches the exhaust device P via the on-off valve V12.
On the other hand, the inert gas used during the process gas replacement operation or the flow rate verification operation is adjusted to an appropriate pressure from the inert gas source L3 by the pressure control device R3, and the on-off valves V7, V9 and V3, V6. To the inlets of the mass flow controllers with flow rate verification function 40-1 and 40-2. Furthermore, in a state where the flow rate is controlled, it reaches the processing chamber D via the on-off valves V8 and V10 from the outlet of the mass flow control device with flow rate verification function 40-3.

For example, the semiconductor manufacturing process is performed by the following operation of the semiconductor manufacturing apparatus. The following operation command signals are all output from the control device C. In the initial state, the on-off valves V1 to V12 are closed.
First, the exhaust device P is put into an operating state, and the on-off valves V2, V3, V5, V6, V7, V8, V9, V10 and V12 are opened with an inert gas (for example, nitrogen) controlled to an appropriate pressure in the pressure control device R3. To introduce. At this time, the mass flow controllers with flow rate verification function 40-1, 40-2 and 40-3 are fully opened, and the inside of the pipe line and the inside of the processing chamber D are purged.

  Subsequently, the control device C closes the on-off valves V3, V5, V6, and V9, opens V1, and supplies a predetermined flow rate control signal to the mass flow rate control devices 40-1 and 40-3 with flow rate verification function. Is introduced from the process gas source L1 through the mass flow rate control device 40-1 with flow rate verification function, and at the pressure control device R3, the pressure is adjusted to an appropriate pressure. The controlled inert gas is introduced via the mass flow controller with flow rate verification function 40-3, and is introduced into the processing chamber D in a state where the process gas and the inert gas are mixed and diluted. The same applies when the process gas source L2 is used. These operations are repeated to manufacture a semiconductor.

  Therefore, in the verification of the mass flow control device, for example, when the mass flow control device with flow verification function 40-1 is verified, the exhaust device P is operated, and the on-off valves V2, V3, V7, V9, V10, V12 are set. Each is opened, and the inert gas is introduced from the inert gas source L3 to the mass flow controller 40-1 with a flow rate verification function in a state adjusted to an appropriate pressure by the pressure controller R3. Subsequently, an instruction signal for the verification operation mode is output to the mass flow control device with flow verification function 40-1. Alternatively, the exhaust device P is operated, the on-off valves V1, V2, V10, and V12 are opened, and the process gas flow rate verification function is adjusted from the process gas source L1 to an appropriate pressure by the pressure control device R1. It can also be introduced into the mass flow control device 40-1 and output a verification operation mode instruction signal to the mass flow control device 40-1 with a flow rate verification function. The verification operation mode will be described later in detail.

In semiconductor manufacturing, it is said that clean room cleanliness and process gas flow rate control accuracy are directly related to the yield rate of semiconductors. In particular, it has been one of the longing for semiconductor manufacturing that dust generation in the work involving the operator greatly affects the cleanliness of the clean room and makes the vicinity of the semiconductor manufacturing apparatus unattended by remote control. The present invention is based on the prior art in which an operator had to work for several hours in a clean room in order to verify and calibrate the process gas flow rate control periodically or whenever a semiconductor failure occurs. Since the problem can be solved and the remote operation enables the flow rate verification and calibration of the process gas to be determined as needed by the operator, it is very useful.
In the present invention, as described above, the operations of the pressure control device, the on-off valve, the mass flow control device with flow rate verification function, the processing chamber, and the exhaust device are controlled by the control device C. Accordingly, since the entire semiconductor manufacturing apparatus can be operated in an integrated manner while monitoring the semiconductor manufacturing process in the processing chamber and the state of the processing chamber, the flow rate verification operation is automated, and further continuous operation of semiconductor manufacturing becomes possible. In particular, when the mass flow control device is verified, the mass flow control device has a verification function. Therefore, it is only necessary to output a verification operation mode instruction signal from the control device C, which is compared with the conventional method. Then, the control program of the control device becomes very simple.

Next, an embodiment of the operation of the mass flow controller with a flow rate verification function will be described in detail with reference to the accompanying drawings.
<First embodiment>
FIG. 2 is a block diagram showing a first embodiment of the mass flow control device according to the present invention, and FIG. 3 is an arrangement diagram showing the actual arrangement state of each member in the first embodiment.

  As shown in the figure, this mass flow rate control device 40 is provided in the middle of a fluid passage through which a fluid such as liquid or gas flows, for example, a gas pipe 4, and controls this mass flow rate (hereinafter also simply referred to as “flow rate”). It has become. Note that the inside of the semiconductor manufacturing apparatus connected to one end of the gas pipe 4 is evacuated by, for example, the exhaust device P (FIG. 1) as described above. The mass flow control device 40 includes a mass flow control main body 40A and a verification main body 40B that performs mass flow characteristic, which is a feature of the present invention. Specifically, the mass flow controller 40 has a flow path 6 formed of, for example, stainless steel, the fluid inlet 6A is connected to the upstream side of the gas pipe 6, and the fluid outlet 6B is Connected to the downstream side of the gas pipe 6.

  The mass flow control device 40A includes, for example, a mass flow detection means 8, a flow control valve mechanism 10, and a control means 18 including, for example, a microcomputer. The mass flow rate detection means 8 includes a bypass pipe 12, a sensor pipe 14, a sensor circuit 16, and the like, and outputs a flow rate signal S1 detected here to the control means 18. The flow control valve mechanism 10 includes a flow control valve 20, an actuator 26 that drives the flow control valve 20, a valve drive circuit 28 that outputs a valve drive voltage S2 toward the actuator 26, and the like. Then, the control means 18 controls the flow rate so that the flow rate indicated by the flow rate setting signal S0 input from the control device C (FIG. 1) of the semiconductor control device matches the flow rate indicated by the flow rate signal S1. The valve opening degree of the control valve 20 can be controlled by, for example, a PID control method. In the illustrated example, the flow rate control valve mechanism 10 is set on the downstream side of the mass flow rate detection means 8, but it may be positioned upstream of the mass flow rate detection means 8.

  On the other hand, in the illustrated example, the verification main body 40B is installed on the upstream side of the mass flow control main body 40A. The mass flow control main body 40A detects the pressure of the gas, which is a fluid, and the verification valve section 42 that opens and closes the flow path 6, the verification tank section 44 having a predetermined capacity, and the flow path 6. Pressure detecting means 46 for outputting a pressure detection signal. Further, it includes both of the verification valve unit 42, the verification tank unit 44, and the pressure detection unit 46, which control to perform a mass flow rate verification operation. ing.

Specifically, the verification valve unit 42 is formed of, for example, a pneumatic valve, and is provided on the most upstream side of the flow path 6 in the verification main body 40B. The tank valve opening / closing which is a command from the verification control means 48 is provided. It is opened and closed by a signal S3 so that the flow path 6 can be blocked as necessary. As the pneumatic valve constituting the verification valve section 42, for example, an actuatorless small valve mechanism incorporating a three-way valve and a fully-closing diaphragm can be used.
This actuatorless small valve mechanism selectively switches between a fully open state of the valve opening and a fully closed state by completely bending the fully closed diaphragm by the working air introduced from the working air inlet 43 (see FIG. 3). In FIG. 3, it is detachably provided in a mounting recess 47 formed in the apparatus housing 45. The configuration of this actuatorless small valve mechanism will be described in the description of the zero point measuring valve unit used in the second embodiment to be described later. The pressure detecting means 46 is composed of a capamanometer, for example, and can detect the pressure of the gas in the flow path 6 and output the detected value to the detection control means 48 as a pressure signal S4. .

The test tank unit 44 is formed of a tank body 50 made of, for example, stainless steel, and is provided between the test valve unit 42 and the pressure detection means 46. The tank main body 50 is set to a predetermined flow rate, for example, a capacity of about 40 cm ³ , and is interposed in the middle of the flow path 6 and is provided with a gas inlet 50A and an outlet 50B at the bottom of the tank main body 50, The flowing gas always passes through the tank body 50. Further, for example, a platinum temperature sensor is attached as a temperature detecting means 51 in the vicinity of the tank main body 50, that is, here, the upper surface of the ceiling of the tank main body 50, and a signal indicating the detected temperature is sent to the test control means. 48 can be input.

Further, the verification control means 48 includes a reference data memory 52A for storing a pressure change (reference pressure change) serving as a reference for the gas flow when the flow rate verification operation is performed, and a gas acquired when the flow rate verification operation is performed. A test data memory 52B for storing a flow pressure change is connected.
Further, the test control means 48 is connected to a display means 54 such as a liquid crystal display for displaying the test result and the like, and an alarm means 56 for issuing an alarm by flashing sound or light when necessary. .
Then, the calibration control means 48 outputs a calibration signal S10 to the sensor circuit 16 of the mass flow rate detection means 8 as necessary, and can calibrate the sensor circuit 16 appropriately based on the calibration result. ing. Further, the test control means 48 and the control means 18 of the mass flow rate control main body 40A are interlocked as necessary.

Next, the operation of the mass flow control device of the present invention configured as described above will be described.
First, there are two types of operations of the mass flow control device 40: a normal operation mode in which a process gas is actually flow-controlled toward a semiconductor manufacturing apparatus or the like, and a verification operation mode in which operations related to mass flow verification are performed. . The verification operation mode includes a reference pressure change characteristic routine for obtaining a reference pressure change characteristic, and a main verification routine for actually performing the verification operation.

  First, the normal operation mode will be briefly described. In this case, the operation on the test body 40B side is in a pause state. That is, the control means 18 of the mass flow rate control main body 40A allows the flow rate indicated by the flow rate setting signal S0 input from the control device C of the semiconductor control device to match the flow rate indicated by the flow rate signal S1. For example, the valve opening degree of the flow control valve 20 is continuously controlled by the PID control method. As a result, the processing gas having the required mass flow rate is supplied to the downstream semiconductor manufacturing apparatus or the like.

Next, the verification operation mode will be described.
Among the verification operation modes, the standard pressure change characteristic routine is used mainly when the device is shipped from the factory or when this device is installed in a clean room at the shipping destination, etc. Trying to get. Further, the verification routine is periodically or irregularly performed in a clean room or the like at the shipping destination to inspect whether or not the accuracy of the control flow rate is maintained high. FIG. 4 is a diagram showing a timing chart of each signal in the verification operation mode of the mass flow control device, FIG. 5 is a flowchart showing each step of the reference pressure change characteristic routine, and FIG. 6 shows each step of this verification routine. The flowchart and FIG. 7 are graphs showing an example of changes in the pressure signal in the reference pressure change characteristic routine and the main verification routine.

  This verification routine detects the step of setting the verification flow rate, the step of flowing the verification fluid (gas) stably in the flow path 6, and the pressure of the flowing fluid and the temperature of the verification tank unit 44. The initial pressure and the initial temperature, the step of closing the flow path 6 by closing the verification valve portion 42, and the flow of the fluid flowing out from the verification tank portion 44 after the verification valve portion 42 is closed. The process mainly includes a step of measuring a pressure change and a step of obtaining a test result based on the measured pressure change and a reference pressure change characteristic obtained in advance. First, the reference pressure change characteristic is obtained. The reference pressure change characteristic routine will be described.

<Routine for reference pressure change characteristics>
The main process of this reference pressure change characteristic routine is substantially the same as the operation of this test routine except for the process of comparing pressure changes. Here, for example, N ₂ gas is used as the fluid, but process gas can also be used. As shown in FIGS. 2, 4 and 5, when the reference pressure change characteristic routine is started, the verification valve unit 42 is opened (step S1). Then, at time t1 (see FIG. 4A), the flow rate setting signal S0 is set to be full scale (5 V: volts) at the maximum%, for example, 100% (step S2). In this verification operation mode, unlike the normal operation mode, the flow rate setting signal S0 is output from the control device C of the semiconductor control device to the control means 18 via the verification control means 48. Therefore, the control unit 18 performs a normal flow rate control operation by regarding the signal input from the verification control unit 48 as the flow rate setting signal S0. In general, the flow rate control signal S0 can be changed in the range of 0V to 5V, and is preset so that the full scale (maximum flow rate) is 100% when 5V.

As described above, when 5V is set as the flow control signal S0, the control means 18 outputs the valve drive voltage S2 (see FIG. 4C) via the valve drive circuit 28, which is commensurate with the flow control signal S0. The flow control valve 20 is controlled so that the valve opening becomes the same. Thereby, since the N ₂ gas starts to flow downstream, the mass flow rate at that time is detected by the mass flow rate detection means 8, and the detected mass flow rate is used as the flow rate signal S1 (see FIG. 4D). 18 is input. The valve opening is controlled by, for example, the PID control method as in the normal operation mode so that the flow rate signal S1 and the flow rate setting signal S0 match. At this time, the pressure of the gas flow is also detected by the pressure detection means 46, and this pressure signal S4 (see FIG. 4E) is input to the test control means 48.

  In order to stabilize the flow rate of the gas flow in this way, when a predetermined time, for example, about 6 seconds elapses (step S3), the valve driving voltage S2 at that time is fixed to the voltage value at that time at time t2. To fix the valve opening (step S4). Then, if several seconds have elapsed after fixing the valve driving voltage S2, the gas flow pressure from the pressure detection means 46 and the tank temperature from the temperature detection means 51 are stored, and the initial pressure MPO and The initial temperature is MTO (step S5).

If the initial pressure and the initial temperature are measured and stored in this way, the tank valve opening / closing signal S3 is immediately output at time t3 so that the valve is closed (see FIG. 4B), and the verification valve unit. 42 is switched to a closed state (step S6). As a result, the flow path 6 is shut off and the supply of N ₂ gas from the gas supply source is cut off. However, the tank body 50 of the test tank unit 44 is sufficiently filled with N ₂ gas and has a predetermined pressure. Therefore, the N ₂ gas filled in the tank main body 50 flows downstream, and as a result, as shown in FIGS. 4D and 4E, the flow rate signal S1 and the pressure signal S4 are changed. Both will draw characteristic curves that decrease with time. At this time, the downstream side of the gas pipe 4 is continuously evacuated, and the valve opening degree of the flow rate control valve 20 maintains the verification flow rate set in step S2, here 100%. .

  The change in the pressure of the gas flow at this time is measured every moment, for example, every 1 msec (step S7), and the pressure change characteristic at this time is obtained. The measurement of the gas pressure is continued until the gas pressure reaches a predetermined lower limit value. When the gas pressure reaches the lower limit value at time t4, the gas flow is stopped (step S8). The pressure change data obtained by the above operation is stored in the reference data memory 52A as a reference pressure change characteristic (step S9). In this way, a reference pressure change characteristic with a valve opening of 100% is obtained as the set flow rate.

  Such reference pressure change characteristics need to be acquired for a plurality of types of valve openings. For example, the reference pressure change characteristics need to be acquired each time the valve opening is changed by 10%. Therefore, for example, assuming that the valve opening 10% is a lower limit, if the setting of the verification flow rate is not the lower limit (NO in step S10), the setting of the verification flow rate is decreased by a predetermined%, for example, 10%. % Is set (step S11). Then, steps S3 to S9 described above are repeated until the valve opening reaches the lower limit. In this way, reference pressure change characteristics with different valve openings by 10% are obtained, and all of this data is stored in the reference data memory 52A, thereby ending the reference pressure change characteristic routine. .

<Main routine for this test>
Next, a description will be given of a regular test routine that is performed regularly or irregularly. The verification performed periodically is performed to confirm the flow rate control accuracy of the semiconductor manufacturing apparatus, and is performed with the whole or part of the manufacturing line stopped. However, in the conventional method, in order to operate the semiconductor manufacturing apparatus, the operator must directly operate and perform the verification, or remove the mass flow controller and perform the verification offline. Therefore, it is necessary to stop the semiconductor manufacturing apparatus for a long time. In addition, the inspection performed irregularly is a sudden case such as when a defect occurs in semiconductor pattern formation, and is performed for the purpose of investigating the cause. Conventionally, the verification operation is practically impossible, and the production line is stopped when the necessity arises. This routine for this verification is performed remotely by operating the control means of the semiconductor manufacturing apparatus while the mass flow control device 40 is incorporated in the gas supply line of the semiconductor manufacturing apparatus in the clean room. Also here, N ₂ gas is used as the fluid, but it is possible to use process gas.

  In the flowchart shown in FIG. 6, steps S21 to S31 are exactly the same as steps S1 to S11 in the flowchart shown in FIG. 5 except that the name of the acquired pressure change data is changed. That is, as shown in FIG. 2, FIG. 4, and FIG. 6, when the main test routine is started, the test valve unit 42 is opened (step S21). Then, at time t1 (see FIG. 4A), the flow rate setting signal S0 is set to become full scale (5 V: volts) at the maximum%, for example, 100% (step S22). In this verification operation mode, unlike the normal operation mode, the flow rate setting signal S0 is output from the control device C of the semiconductor control device to the control means 18 via the verification control means 48. Therefore, the control unit 18 performs a normal flow rate control operation by regarding the signal input from the verification control unit 48 as the flow rate setting signal S0. As described above, generally, the flow rate control signal S0 can be changed in the range of 0V to 5V, and is preset so that the full scale (maximum flow rate) is 100% at 5V. Yes.

As described above, when 5V is set as the flow control signal S0, the control means 18 outputs the valve drive voltage S2 (see FIG. 4C) via the valve drive circuit 28, which is commensurate with the flow control signal S0. The flow control valve 20 is controlled so that the valve opening becomes the same. Thereby, since the N ₂ gas starts to flow downstream, the mass flow rate at that time is detected by the mass flow rate detection means 8, and the detected mass flow rate is used as the flow rate signal S1 (see FIG. 4D). 18 is input. The valve opening is controlled by the PID control method as described above so that the flow rate signal S1 and the flow rate setting signal S0 coincide. At this time, the pressure of the gas flow is also detected by the pressure detection means 46, and this pressure signal S4 (see FIG. 4E) is input to the test control means 48.

  In order to stabilize the flow rate of the gas flow in this way, when a predetermined time, for example, about 6 seconds elapses (step S23), the valve driving voltage S2 at that time is fixed to the voltage value at that time at time t2. To fix the valve opening (step S24). Then, if several seconds have elapsed after fixing the valve driving voltage S2, the gas flow pressure from the pressure detection means 46 and the tank temperature from the temperature detection means 51 are stored, and the initial pressure PO and The initial temperature is set to TO (step S25).

If the initial pressure and the initial temperature are measured and stored in this way, the tank valve opening / closing signal S3 is immediately output at time t3 so that the valve is closed (see FIG. 4B), and the verification valve unit. 42 is switched to a closed state (step S26). As a result, the flow path 6 is shut off and the supply of N ₂ gas from the gas supply source is cut off. However, the tank body 50 of the test tank unit 44 is sufficiently filled with N ₂ gas and has a predetermined pressure. Therefore, the N ₂ gas filled in the tank main body 50 flows downstream, and as a result, as shown in FIGS. 4D and 4E, the flow rate signal S1 and the pressure signal S4 are changed. Both will draw characteristic curves that decrease with time. At this time, the downstream side of the gas pipe 4 is continuously evacuated, and the valve opening degree of the flow rate control valve 20 is maintained at the verification flow rate set in step S22, here 100%. .

  The change in the pressure of the gas flow at this time is measured every moment, for example, every 1 msec (step S27), and the pressure change characteristic at this time is obtained. The measurement of the gas pressure is continued until the gas pressure reaches a predetermined lower limit value. When the gas pressure reaches the lower limit value at time t4, the gas flow is stopped (step S28). Then, the pressure change data obtained by the above operation is stored in the test data memory 52B as a test pressure change characteristic (step S29). In this way, a verification pressure change characteristic with a valve opening of 100% is obtained as the set flow rate.

  Such a verification pressure change characteristic needs to be acquired for a plurality of types of valve openings as in the case of the reference pressure change characteristic. For example, the verification pressure change characteristic is changed each time the valve opening is changed by 10%. Need to get. Therefore, for example, assuming that the valve opening 10% is a lower limit, if the setting of the verification flow rate is not the lower limit (NO in step S30), the setting of the verification flow rate is decreased by a predetermined%, for example, 10%. % Is set (step S31). The above steps S23 to S29 are repeated until the valve opening reaches the lower limit. In this way, the verification pressure change characteristic with the valve opening being different by 10% is obtained, and all this data is stored in the verification data memory 52B.

If the verification pressure change characteristic is obtained in this way, the verification process is performed by comparing with the reference pressure change characteristic for each valve opening (for each set value of the verification flow rate) (step S32).
Here, the method for obtaining the test accuracy, which is the test result, will also be described with reference to FIG. FIG. 7 is a graph showing an example of a change in the pressure signal 4 in the reference pressure change characteristic routine and the main verification routine when the valve opening is 100%. The characteristic curve X0 shows the reference pressure change when the valve opening is 100%, the characteristic curve X1 shows the verification pressure change characteristic when the valve opening is 100%, and both characteristic curves are the reference data as described above. The data is stored in the memory 52A and the test data memory 52B. The time during which each of the characteristic curves X0 and X1 passes through a predetermined pressure range, that is, between the upper limit reference pressure P1 and the lower limit reference pressure P2, is defined as MΔt and Δt, respectively.

At this time, the test result H is expressed by the following mathematical formula.
H = MΔt / Δt × PO / MPO × (273 + MTO) / (273 + TO) × 100 (%)
MTO: Initial temperature in the reference pressure change characteristic routine TO: Initial temperature in the main test routine MPO: Initial pressure in the reference pressure change characteristic routine PO: Initial pressure in the main test routine

Assuming that MΔt = 17640 msec, Δt = 111420 msec, MPO = 0.4003210 MPa (megapascal), PO = 0.2589058 MPa, MTO = 25.4 ° C., TO = 24.7 ° C. Is as follows.
H = 100.135%
That is, here, if the gas flow rate is controlled in the same manner as at the time of shipment, it means that a flow rate error of 0.135% occurs although it is slight.

Then, the verification process as described above is performed for each valve opening, and the verification accuracy H for each valve opening is obtained (step S32).
If the test result is obtained in this way, the test result is stored, and at the same time, the test result is output and displayed on the display means 54, for example, to inform the operator of the content, or the control device C of the semiconductor control device. The control device C outputs a signal for a necessary treatment process based on the test result (step S33). At the same time, if necessary, the mass flow rate detecting means 8 is automatically calibrated based on the test result and set to output the correct mass flow rate S1 (step S34). This calibration process can be performed by adjusting the gain of the differential circuit 32 (see FIG. 15), which is an amplifier of the sensor circuit 16, for example.

If necessary, the test routine can be repeated a plurality of times to obtain the average value. If automatic calibration using the average value is performed, the calibration accuracy can be further improved. If necessary, the test accuracy is compared with a predetermined allowable range set in advance, and when the test accuracy is larger than the allowable range, the alarm means 56 is driven to alert the operator. It may be transmitted to the control device C of the semiconductor control device. When the automatic calibration is completed as described above, the test routine is terminated.
In this way, the mass flow control device itself is provided with the test valve unit 42, the test tank unit 44, etc., and after the test valve unit 42 is closed and the supply of fluid is stopped, the test tank unit 44 By detecting the pressure change of the flowing fluid and comparing this pressure change with, for example, a reference pressure change as a reference, it is possible to test whether the mass flow rate of the flowing fluid can be accurately controlled.

Further, since the above-described verification operation can be performed while the mass flow controller 40 is incorporated in the gas supply system of the semiconductor manufacturing apparatus, the verification operation can be performed in an extremely short time. Rate and good product rate can be improved.
In the above embodiment, the verification operation was performed by changing the valve opening (set value of the verification temperature) by 10%. However, the present invention is not limited to this numerical example. Further, the arrangement order of the detection means 46 and the detection tank portion 44 with respect to the flow path 6 may be reversed on the upstream side and the downstream side. Furthermore, although the inlet 50A and the outlet 50B of the flow path 6 are separately provided for the tank body 50 here, the present invention is not limited to this, and a single branch pipe is formed for the flow path 6 and this branch is formed. The tank body 50 may be connected to the pipe in a T shape.

Various processes as described in this embodiment may be performed by digital processing or analog processing. In particular, when digital processing is performed, the data may be discrete depending on the sampling frequency for capturing various data. In this case, by rounding the data from the least significant digit, for example, FIG. In the graph shown, it is possible to find coincident points such as pressure data.
In the first embodiment, when the zero point adjustment is performed, the flow rate signal S1 is obtained in a state where the flow of the gas in the flow path 6 is stopped and stabilized with the verification valve portion 42 closed. The zero point is adjusted based on this value.

<Second embodiment>
Next, a second embodiment of the mass flow control device according to the present invention will be described.
In the second embodiment, a function capable of performing zero-point adjustment with high accuracy is added, and at the same time, the apparatus itself is made compact and compact.

  In this type of mass flow control device, the zero point of the flow rate detection is inevitably shifted slightly due to changes over time, so the zero point adjustment is performed periodically or irregularly. It is desirable to completely stop the flow of fluid (including gas and liquid) inside the apparatus in order to increase the flow rate. In this case, regarding the flow control valve 20 using the diaphragm, even if it is closed, it is difficult to completely shut off the flow of the fluid due to its characteristics, and although it is very slight, it is extremely minute. It was inevitable that a large amount of leak occurred. This small amount of leakage was not particularly problematic when the design rules in the semiconductor manufacturing process were not so strict, but when the design rules became more strict due to demands for further miniaturization, thinning, and higher integration, The extremely small amount of leakage is no longer negligible.

In the second embodiment, a small and compact zero point measuring valve portion is provided in order to completely eliminate an extremely small amount of leak. This point will be described in detail below.
FIG. 8 is a block diagram showing a second embodiment of the mass flow control device according to the present invention, FIG. 9 is an arrangement diagram showing the actual arrangement state of each member in the second embodiment, and FIG. 10 is a flow control valve. FIG. 11 is a cross-sectional view showing a fully-closed diaphragm of the zero point measuring valve unit, and FIG. 12 is a flowchart showing the flow of the zero point measuring step.
The same components as those shown in FIGS. 2 and 3 are denoted by the same reference numerals, and the description thereof is omitted. Here, a case will be described in which the actuator-less small valve mechanism used in the previous verification valve unit 42 is used as the zero point measurement valve unit.

  As shown in FIGS. 8 and 9, the zero point measurement valve unit 60 is provided on the most downstream side of the flow path 6 and is positioned immediately before the fluid outlet 6 </ b> A. Specifically, a mounting recess 62 is provided on the lower surface side (in FIG. 8) of the device housing 45 of the mass flow control device, and the zero point measuring valve unit 60 is liquid-tight or air-tight in the mounting recess 62. It is designed to be attached. The mounting recess 62 is disposed at a position facing the diaphragm 22 of the flow control valve mechanism 10.

  As shown in FIG. 10, a fluid reservoir chamber 64 is formed in the interior of the mounting recess 62 by scraping the device housing 45 deeper. A central portion of the ceiling of the fluid reservoir chamber 64 is formed to protrude slightly downward in FIG. 10, and this portion communicates with the valve port 24 on the flow control valve mechanism 10 side so as to communicate with the communication passage 66. The gas flowing through the valve port 24 can flow into the fluid reservoir 64. Therefore, with respect to the fluid reservoir chamber 64, the lower end opening portion of the communication passage 66 functions as a fluid inlet portion 68 serving as a valve port. Further, the fluid reservoir chamber 64 is provided with a fluid outlet portion 70 through which gas flows out. The fluid outlet portion 70 communicates with the fluid outlet 6B via a flow path 72.

  A ring-shaped elastic seal member 74 having a fluorine-based corrosion resistance such as, for example, a tetrafluoroethylene resin is provided so as to partially protrude downward around the fluid inlet 68 serving as the valve port. As will be described later, when the valve is in the closed state, the fluid inlet 68 serving as the valve port is completely liquid-tight or air-tightly closed so that the gas flow can be completely blocked. A metal full-closed diaphragm 76 that can be bent and deformed is provided so as to define a lower portion of the fluid reservoir chamber 64. The fully-closing diaphragm 6 has a curved surface portion 76A that is formed in a curved shape so as to protrude downward in the center thereof, and its peripheral portion is closely fitted in the mounting recess 62. It is pressed and fixed by a fixing member 78. The fixing member 78 is fastened and fixed with a screw or the like (not shown).

  Here, the curved surface portion 76A has a shape that is a part of a substantially spherical shell, specifically, a part of a spherical shell that is closer to a flat surface than a hemispherical shell. The fully closed diaphragm 6 may be formed to have a planar shape without providing the curved surface portion 76A. The fixing member 78 is provided with pressing means 80 for pressing the fully closing diaphragm 76 toward the fluid inlet portion 68 to close the fluid inlet portion 68 functioning as a valve port. The pressing means 80 is provided on the side opposite to the fluid reservoir chamber 64 (lower side in FIG. 9) with the full-closed diaphragm 76 sandwiched between them by forming the upper surface of the fixing member 78 into a concave shape. The working space 82 and a valve mechanism 84 capable of supplying and discharging pressurized gas, for example, pressurized air, into the working space 82 are configured. By driving the valve mechanism 84, the pressurized gas can be supplied to and discharged from the working space 82 as necessary. When the pressurized gas is supplied, the valve mechanism 84 is used to fully close the curved surface 76A. The diaphragm 76 can be bent and deformed so that the fluid inlet 68 can be fully closed.

  Therefore, at the normal time when pressurized gas is not supplied to the working space 82, the gas inlet portion 68 is in a fully open state, and is a normally open type on-off valve. The valve mechanism 84 is composed of, for example, an electromagnetic three-way valve. By incorporating the electromagnetic three-way valve in the fixing member 78, the overall size and size can be reduced. In this case, a seal member 86 made of an O-ring or the like is interposed between the periphery of the fixing member 78 and the inner surface of the mounting recess 62, and is connected by screws (not shown). Pressurized air is prevented from leaking outside. As described above, by using the electromagnetic three-way valve as the valve mechanism 84, the pressurized air constantly applied to one of the three-way valves can be supplied and discharged into the working space 82 as necessary. The pressurized air is introduced from the working air inlet 85. By using an electromagnetic three-way valve as the valve mechanism 84 as described above, a small and compact actuatorless small valve mechanism can be obtained as the zero point measuring valve unit 60. The operation of the zero point measuring valve unit 60 is controlled by the test control means 48.

Next, the zero point measuring process of the flow rate sensor performed using the zero point measuring valve unit 60 configured as described above will be described.
This zero point measurement step is performed regularly or irregularly, and in particular, is performed immediately before executing the reference pressure change characteristic routine shown in FIG. 5 or immediately before executing the main verification routine shown in FIG. Is preferred.
As shown in FIG. 12, in order to perform this zero point measuring step, first, here, the test valve portion 42 located at the uppermost stream of the flow path 6 and the above-described zero point measurement valve section located at the most downstream position of the flow path 6. The valve 60 is closed by closing both of the valve 60 and the gas flowing in the flow path 6 is completely cut off and stopped (S01). That is, the gas flow in the sensor tube 14 is completely stopped. At this time, the flow control valve 20 of the flow control valve mechanism 10 is kept open (S02).

  In such a state, when a predetermined time has passed and the gas flow in the flow path 6, particularly in the sensor tube 14, is completely stopped and becomes stable (S 03), the sensor circuit 16 at that time The flow rate signal S1 is detected, and the detected value at this time is stored in a memory (not shown) of the control means 18 as a zero point deviation amount (S04). In other words, by this, the measurement system (flow rate sensor) in the test control means 48 and the control means 18 is electrically set (offset adjustment) as “channel zero”. In this case, as described above, the zero point measurement valve unit 60 can completely block the leakage of gas (fluid), and therefore can perform zero point measurement with high accuracy. Here, the zero point adjustment is not performed yet, and the above-described deviation amount is stored, and finally, the zero point adjustment is performed automatically in the test routine or according to the operator's instruction. That is, the zero point adjustment and the flow rate deviation adjustment are performed by automatically calibrating the zero point deviation amount and the flow rate deviation amount obtained in the main examination routine in S34 of the main examination routine shown in FIG. . In this case, each deviation amount of the measurement result may be displayed without performing automatic calibration, and if necessary, calibration may be performed by an operator viewing and instructing this.

Returning to FIG. 12, if the value of the flow rate signal S1 is stored in S04, the flow rate control valve 20 is shifted to a normal control state (S05), and then the verification valve unit 42 and the zero point measurement valve unit 60 are transferred. Are both opened (S06). Then, in the case of the reference pressure change characteristic routine, the routine proceeds to S2 in FIG. 5 (excluding S1), and in the case of the main examination routine, the routine proceeds to S22 in FIG. 5 (excluding S21) (S07).
In the above-described case, as shown in FIG. 11, the diameter of the hemispherical curved surface portion 76A of the fully closed diaphragm 76 is D, the radius R, the pressure of the pressurized air is P1, and the pressure in the fluid reservoir chamber 64 is P2. As a result of the experiment, it was confirmed that the range satisfying the following relational expression can maintain the fully closed state without leakage.
2 <R / D <10 (when P1-P2 ≧ 0.1 MPa)
The shape of the curved surface portion 76A is a part of a spherical shell, for example, a hemispherical shell, but is not limited thereto, and the gas flow is completely stopped such as a part of an elliptical shell. Any curved surface may be used as long as the fully closed state can be realized, and the fully closed diaphragm 76 may be planar as described above.

In addition, since an electromagnetic three-way valve is used as the valve mechanism 84 and an actuator-less small valve mechanism having the built-in valve is used as the zero-point measuring valve unit 60, it is possible to achieve a small size and a small space.
Although depending on the design dimensions of the apparatus, the zero-point measuring valve portion 60 is arranged to face the flow control valve mechanism 10, so that the valve opening 24 opened and closed by the diaphragm 22 and the fluid inlet of the fluid reservoir chamber 64 are arranged. The volume of the communication path 66 that communicates with the portion 68, that is, the dead volume that cannot be controlled when the gas is flowed, can be greatly reduced. This can bring about an effect of minimizing the flow overshoot at the initial operation of the semiconductor manufacturing apparatus or at the time of switching the process gas and minimizing the amount of discarded gas for exhausting the fluid that cannot be controlled.

Further, as described above, such an actuatorless small valve mechanism can be applied to the verification valve unit 42 shown in FIG.
In the second embodiment, an actuator-less small valve mechanism incorporating an electromagnetic three-way valve is used as the pressing means 80 of the zero-point measuring valve portion 60. Instead, as shown in FIG. Alternatively, a piston-type actuator having a piston 90 that contacts and presses the fully-closing diaphragm 76 may be used. At this time, the piston 90, for example, connects a separately disposed electromagnetic three-way valve and the piston 90 by a pipe line (not shown), and is operated by the pressure of pressurized air supplied and exhausted by the operation of the electromagnetic three-way valve.
The zero point measuring valve section 60 is provided on the opposite side of the verification valve section 42 with the bypass pipe 12 and the sensor pipe 14 interposed therebetween. Therefore, for example, when the verification valve portion 42 is provided on the downstream side of the bypass pipe 12, the zero point measurement valve portion 60 is provided on the upstream side of the bypass pipe 12.

It is a conceptual diagram which shows the Example of the semiconductor manufacturing apparatus carrying the mass flow rate control apparatus with a flow volume verification function which concerns on this invention. It is a block block diagram which shows 1st Example of the mass flow control apparatus which concerns on this invention. FIG. 3 is an arrangement diagram showing an actual arrangement state of each member in the first embodiment. It is a figure which shows the timing chart of each signal at the time of the verification operation mode of a mass flow control apparatus. It is a flowchart which shows each step of the routine for reference pressure change characteristics. It is a flowchart which shows each step of this test routine. It is a graph which shows an example of the change of the pressure signal in the routine for reference pressure change characteristics, and this inspection routine. It is a block block diagram which shows 2nd Example of the mass flow control apparatus which concerns on this invention. It is an arrangement figure showing the actual arrangement state of each member in the 2nd example. It is a schematic diagram which shows the attachment state of the flow control valve and the valve part for zero point measurement. It is sectional drawing which shows the diaphragm for full closure of the valve | bulb part for zero point measurement. It is a flowchart which shows the flow of a zero point measurement process. It is a figure which shows the piston type actuator which has a piston.

Explanation of symbols

1: Semiconductor manufacturing apparatus L1, L2: Process gas source, L3: Inert gas source R1, R2, R3: Pressure control devices V1, V2, V3, V4, V5, V6, V7, V8, V9, V10, V11, V12: On-off valve D: Processing chamber, P: Exhaust device, C: Control device 4: Gas pipe (fluid passage), 6: Flow path, 8: Mass flow rate detection means, 10: Flow control valve mechanism 12: Bypass pipe, 14: Sensor tube, 16: Sensor circuit, 18: Control means, 20: Flow control valve 28: Valve drive circuit 40, 40-1, 40-2, 40-3: Mass flow controller with verification function 40A: Mass flow Control body, 40B: Verification body 42: Verification valve section, 44: Verification tank section, 46: Pressure detection means, 48: Verification control means 50: Tank body, 51: Temperature detection means 52A: Reference data memory, 52B : Examination Data memory 54: display means, 56: alarm means,
60: Zero point measuring valve section, 64: Fluid reservoir chamber, 68: Fluid inlet section, 70: Fluid outlet section, 76: Fully closed diaphragm, 78: Fixing member, 80: Pressing means, 82: Working space, 84: Valve Mechanism S0: Flow rate setting signal, S1: Flow rate signal, S2: Valve drive voltage, S3: Tank valve open / close signal S4: Pressure signal

Claims (4)

  A semiconductor manufacturing apparatus having a mass flow control device and an opening / closing valve in a fluid supply path and having an exhaust device at a terminal, wherein the semiconductor manufacturing apparatus operates the mass flow control device, the opening / closing valve, the exhaust device, etc. A semiconductor manufacturing apparatus, comprising: a control device that controls the control, wherein the mass flow control device is a mass flow control device having a flow control verification function and / or a flow rate calibration function. The control device outputs a predetermined operation signal to the on-off valve and the exhaust device during flow rate verification, and outputs a flow rate verification operation signal to the mass flow control device simultaneously or afterwards. 2. The semiconductor manufacturing apparatus according to 1. The mass flow rate control device includes a mass flow rate detecting means for detecting a mass flow rate of the fluid flowing in the flow channel and outputting a flow rate signal to the flow channel for flowing the fluid, and changing the valve opening by the valve drive signal. A mass flow control device provided with a flow rate control valve mechanism for controlling a flow rate, and provided with a control means for controlling the flow rate control valve mechanism based on a flow rate setting signal input from the outside and the flow rate signal,
Further, the flow path is provided with a verification valve section for opening and closing the flow path, a verification tank section having a predetermined capacity, and a pressure detection means for detecting the pressure of the fluid and outputting a pressure detection signal. The mass flow rate control device is configured to include verification control means for controlling the mass flow rate verification operation using the verification valve, the verification tank unit, and the pressure detection means. The semiconductor manufacturing apparatus according to claim 1. 4. The mass flow control device according to claim 1, wherein the mass flow control device is provided with a zero point measurement valve portion that opens and closes an outlet side of the flow channel when the zero point is measured in the flow channel. The semiconductor manufacturing apparatus in any one of.