JPH07104805A - Method and device for controlling controller of semiconductor manufacturing device - Google Patents

Abstract

PURPOSE:To provide a method and device for controlling controller of semicon ductor manufacturing device which can stabilize a second-order system manipu lated variable and can provide a stable temperature control characteristic inside a furnace by correcting a first-order system manipulated variable to be any suitable manipulated variable corresponding to the value of the second-order system manipulated variable. CONSTITUTION:In the controller of the semiconductor manufacturing device for a cascade control system, a decision part 6 decides whether a second-order system manipulated variable P2 outputted from a PID2 is settled within the manipulation enable range of a second-order control system or not. When it is settled within that range, a first-order system manipulated variable P1 as the target value in the case of calculating the second-order system manipulated variable P2 is stored in a memory 5b as the suitable first-order system manipulated variable P1' but when the second-order system manipulated variable P2 gets out of that range, the suitable first-order system manipulated variable P1' is outputted from the part of the memory 5b to the PID2 as the second-order system target value SV'.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control apparatus of a cascade control system used for temperature control of an electric heating furnace or the like as a semiconductor manufacturing apparatus and its control method, and more particularly, to a time for stabilizing the temperature to a target value. The present invention relates to a control method for a control device of a semiconductor manufacturing apparatus and a control device for the same, which can shorten and obtain stable temperature control characteristics.

[0002]

2. Description of the Related Art As a control device for controlling the temperature of an electric heating furnace of a semiconductor manufacturing apparatus, a DDC (Direct Digital C
ontrol), which is a type of cascade control. A control device and a control method for controlling the temperature of a conventional electric heating furnace will be described with reference to FIG. FIG. 6 is a schematic block diagram of a control device of a conventional semiconductor manufacturing apparatus.

As a control device for a conventional electric heating furnace, 1
Primary operation unit (PID) 1 of PID (proportional + integral + derivative) control system for secondary control, secondary operation unit (PID) 2 of PID control system for secondary control, heater 3, and furnace 4 and
A cascade control system connected in series as shown in FIG. 6 is connected so that the measured value of the temperature in the furnace 4 is fed back to the primary calculation unit 1 and the temperature of the heater 3 is fed back to the secondary calculation unit 2. there were.

Here, the primary calculation unit 1 has a target value and a furnace 4
Difference (deviation) from the primary system controlled variable fed back from
Is input, the primary operation amount (= secondary system target value) is output from the primary calculation unit 1, and the secondary system target value and the secondary system fed back from the heater 3 are supplied to the secondary calculation unit 2. The difference (deviation) from the control amount is input, the secondary system operation amount is output from the secondary calculation unit 2 to the heater 3 as electric power, and the temperature of the heater 3 is controlled as the secondary system control amount in the heater 3 Is adjusting the temperature.

The primary control system adjusts the temperature of the furnace 4 by comparing a preset target value with the actually measured temperature of the furnace 4 and raising or lowering the temperature of the heater 3.
The secondary control system adjusts the temperature of the heater 3 by controlling the electric power supplied to the heater 3 with the operation amount of the primary control system as a target value. As described above, in the cascade control, the operation amount of the primary control system is reflected in the target value of the secondary control system, thereby enabling fine control and stabilizing the temperature in the furnace 4 to the target value. Was there.

The operating amounts of the primary control system and the secondary control system have an operable range. Here, the operating amount of the primary control system is 0% at 0 ° C. of the heater 3 and 100% at 1400 ° C. And the operation amount of the secondary control system is set such that the minimum electric power Min is 0% and the maximum electric power Max is 100%.

Next, a control method in the control device for the conventional electric heating furnace will be described with reference to the flow charts of FIGS. 7 is a flowchart showing the entire cascade control, FIG. 8 is a flowchart showing control of the primary control system, and FIG. 9 is a flowchart showing control of the secondary control system.

As shown in FIG. 7, the overall flow of the cascade control is such that the target value SV is input from the operation panel (60
1), the temperature in the furnace 4 is measured by an input circuit or the like using a thermocouple, and the primary system controlled variable PV is set (602). Then, the proportional gain K in the PID calculation is set (60
3), the integration time TI is set (604) and the differential time TD is set (605) for each of the primary system and the secondary system. Next, the PID process (PID1) of the primary control system is performed to obtain the primary system manipulated variable P1 for controlling the temperature of the furnace 4 (611), and the obtained primary system manipulated variable P1 is secondary It is input as the system target value SV '(612), and P of the secondary control system is input.
The secondary system operation amount P2 is obtained by performing ID processing (PID2) (613), the secondary system operation amount P2 is converted into electric power (614), and the electric power to the heater 3 is controlled to control the heater 3. The temperature is adjusted so that the temperature in the furnace 4 approaches the target value SV.

Further, as shown in FIG. 8, P of the primary control system is
In the ID process (PID1), the preset target temperature S
The deviation E (SV-PV) is calculated by comparing V with the primary system controlled variable PV, which is the temperature in the furnace 4 measured (621), and P
The ID calculation is performed to calculate the PID calculation output X1 (62
2), PID calculation output X1 is used as the primary system manipulated variable P1 (623). Here, the primary system manipulated variable P1 is the manipulated variable of the temperature of the heater 3 required to bring the temperature in the furnace 4 close to the target value SV, and this becomes the target value SV 'of the secondary control system. .

As shown in FIG. 9, in the PID processing (PID2) of the secondary control system, the primary system manipulated variable P1 obtained by the PID processing of the primary control system is measured as the secondary system target value SV '. Secondary system controlled variable PV 'which is the temperature of the heated heater 3
And the deviation E ′ (SV′−PV ′) is calculated (63
1), the PID calculation is performed to calculate the PID calculation output X2 (632), and the PID calculation output X2 is input to the heater 3 as the secondary system operation amount P2 (633).

[0011]

However, in the above-mentioned conventional controller and method for controlling a semiconductor manufacturing apparatus,
Depending on the I operation (integration operation) output in the PID processing of the primary control system, the secondary system target value, which is the primary system operation amount, may be set to exceed the limit of the secondary system operation amount. There was a problem that the temperature control became unstable in the process of stabilizing the temperature in the furnace, resulting in an overshoot state.

Specifically, even if the primary control amount in the primary control system exceeds the target value and the primary control amount is decreased, the secondary control amount in the secondary control system is decreased. Until 100% or less, electric power is supplied so as to raise the heater, and as a result, the primary system control amount increases, resulting in an overshoot state, which takes time to stabilize, and further overshoot There is a problem in that the heater is damaged when becomes larger.

The present invention has been made in view of the above circumstances, and stabilizes the secondary system manipulated variable by correcting the primary system manipulated variable from the value of the secondary system manipulated variable to an appropriate manipulated variable. It is an object of the present invention to provide a control method of a control device of a semiconductor manufacturing apparatus and a control device therefor capable of obtaining stable temperature control characteristics in a furnace.

[0014]

According to a first aspect of the present invention for solving the problems of the above-mentioned conventional example, a heater for adjusting the temperature in the furnace, and a first target value of the temperature in the furnace are provided. A first control system having a first calculation unit that calculates a first manipulated variable by performing a PID calculation based on a first controlled variable that is a temperature measured in the furnace and a target value of The first operation amount calculated by the first calculation unit is set as a second target value, and PID calculation is performed based on the second target value and a second controlled amount that is the output temperature of the heater. , A second control system having a second arithmetic unit for calculating a second manipulated variable, is output from the second arithmetic unit in a method for controlling a control device of a semiconductor manufacturing apparatus in which a second control system is connected to a cascade control system. It is determined whether the second manipulated variable is within the preset range, and An appropriate operation amount stored is characterized by outputting the second control system when the were first in the range instead of the first manipulated variable output from the arithmetic unit if Re.

According to a second aspect of the present invention for solving the problem of the conventional example, in the control device of the semiconductor manufacturing apparatus according to the first aspect, the second manipulated variable output from the second arithmetic unit is set. A determination unit that reads and determines whether or not it is within a preset range, and stores a first operation amount output from the first calculation unit when it is within the range as an appropriate operation amount, and stores it outside the range. In this case, a storage unit that outputs the appropriate operation amount instead of the first operation amount output from the first calculation unit is provided.

[0016]

According to the first aspect of the present invention, it is determined whether the second manipulated variable output from the second computing unit is within a preset range. When it is within the range instead of the first manipulated variable output from the section, the first
The operation amount is stored as an appropriate operation amount, and the appropriate operation amount is output to the second control system as the control method of the control device of the semiconductor manufacturing apparatus. Even so, an appropriate manipulated variable within the range can be used as the second target value to perform the PID computation in the second computing unit of the second control system so that the second manipulated variable is always within the range. Since the temperature can be controlled, the temperature inside the furnace can be quickly stabilized to a target value, and stable temperature control can be performed.

According to the second aspect of the present invention, the determination unit reads the second operation amount output from the second calculation unit, determines whether the second operation amount is within a preset range, and determines that the range is within the preset range. Sometimes the first operation amount output from the first calculation unit is stored in the storage unit as an appropriate operation amount, and when it is out of the range, the first operation amount is stored.
The control device for the semiconductor manufacturing apparatus according to claim 1, wherein an appropriate amount of operation is output from the storage unit instead of the first amount of operation output from the calculation unit of the second operation amount. Even if an appropriate manipulated variable within the range is used as the second target value, PID computation can be performed by the second computing unit of the second control system, and the second manipulated variable is controlled so as to always fall within the range. Therefore, the temperature in the furnace can be quickly stabilized to the target value, and stable temperature control can be performed.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration block diagram of a control device of a semiconductor manufacturing apparatus according to an embodiment of the present invention. It should be noted that the same components as those in FIG. 6 will be described with the same reference numerals. In addition, in this embodiment, the semiconductor manufacturing apparatus 1
A control system of a cascade control system for controlling the temperature of an electric heating furnace which is a kind will be described as an example.

The basic structure of the control device of the semiconductor manufacturing apparatus of this embodiment is almost the same as that of the conventional control device shown in FIG. 6, and by adjusting the temperature of the heater 3, the temperature of the furnace 4 is adjusted. And a secondary control system that controls the temperature of the heater 3 by adjusting the electric power supplied to the heater 3 with the operation amount of the primary control system as a target value. ing.

The control device of the semiconductor manufacturing apparatus of this embodiment is
Primary operation unit (PID1) 1 which is the operation unit of the primary control system
And a secondary operation unit (PID2) which is an operation unit of the secondary control system
2, the heater 3, and the furnace 4 are connected in series, and the furnace 4
The temperature of P is measured by a sensor using a thermocouple and P
The temperature of heater 3 is fed back to ID1 and PID
Feedback is given to 2.

Specifically, the difference (deviation E = SV-PV) between the target value SV and the primary system controlled variable PV fed back from the furnace 4 is input to PID1, and 1 is input from PID1.
Secondary system manipulated variable P1 (generally the secondary system target value SV ')
Is output, and the difference (deviation E ′ = SV′−PV ′) between the secondary system target value SV ′ and the secondary system control amount PV ′ fed back from the heater 3 is input to PID2, and 2 is output from PID2. The secondary system manipulated variable P2 is converted into electric power and output to the heater 3, and the heater 3 controls the temperature as the secondary system controlled variable PV 'to adjust the temperature in the furnace 4.

As a characteristic part of this embodiment, the PI
A memory 5a for storing the PID operation output X1 of D1 as the primary system manipulated variable P1 and a memory for storing the latest appropriate primary system manipulated variable P1 'when the secondary system manipulated variable P2 is within the operable range. 5b and P based on the primary system manipulated variables P1 and P1 '
The PID calculation output X2 calculated with ID2 is used as the secondary system manipulated variable P
A memory 5c for storing as 2 and a judgment unit 6 for judging whether or not the secondary system operation amount P2 is within the operable range are provided, and output based on the judgment result of the judgment unit 6. The memories 5a, 5b and 5c are accessed by the control signal.

In the controller of the semiconductor manufacturing apparatus of this embodiment, the primary system operation amount P1 is the temperature of the heater 3 at 0.degree.
Is set to 0%, 1400 ° C. is set to 100%, and the secondary system manipulated variable P2 has a minimum power Min of 0% and a maximum power Max of 100.
%, 0% ≤ P1 ≤ 100%, 0% ≤ P2
It can be operated within the range of ≤100%.

Next, the judging section 6 which is a characteristic part of this embodiment.
Then, the operation of the memories 5a, 5b, 5c will be specifically described with reference to FIG. In the conventional example, the primary system manipulated variable P1 output from the primary control system is directly used as the secondary system target value SV '.
Therefore, the secondary system manipulated variable P2 (= power supplied to the heater 3) obtained by the PID calculation of PID2 is
There was a case where the temperature in the furnace 4 overshooted because it was too large or too small, and it was difficult to stabilize. However, in the controller of the semiconductor manufacturing apparatus of this embodiment, the primary system manipulated variable P1 remains unchanged. A determination unit 6 and memories 5a, 5b, 5c are provided as a mechanism for checking whether the secondary system target value SV 'is appropriate.

First, the memory 5a uses the target value SV of the primary control system and the measured value of the temperature in the furnace 4 (primary system control amount PV) to calculate the PID calculation output X in PID1.
This is a memory for storing 1 as the primary system manipulated variable P1. Therefore, the content of the memory 5a is the PID of the primary control system.
It is updated every time an operation is performed. Then, in order to calculate the secondary system manipulated variable P2 with this primary system manipulated variable P1 as the secondary system target value SV ', the primary system manipulated variable P1 is sent from the memory 5a to the PID2. There is.

The memory 5c is a memory in which the PID calculation output X2 calculated in PID2 is converted into electric power, the electric power value is read as the secondary system operation amount P2, and is temporarily stored. The memory 5c is connected to the determination unit 6, and whether or not the secondary system operation amount P2 is a value in an appropriate range in the determination unit 6, that is, a target value when the secondary system operation amount P2 is calculated. Therefore, it is determined whether the primary system manipulated variable P1 is Therefore, the memory 5c
The content of is also updated every time calculation is performed by PID2.

The determination unit 6 is set with an operation range of the secondary system operation amount P2 (electric power minimum Min to electric power maximum Max), the electric power minimum Min is 0%, and the electric power maximum Max is 100%.
Is a means for reading the electric power value of the secondary system manipulated variable P2 from the memory 5c to determine whether it is within the set range, and is realized by a microcomputer or the like.

Then, the judging section 6 judges whether or not the secondary system operation amount P2 of the PID calculation output X2 calculated by PID2 is within the operable range, that is, 0% ≤P2≤100%. , The primary system manipulated variable P1 that gives the secondary system manipulated variable P2 that satisfies 0% ≦ P2 ≦ 100% is an appropriate manipulated variable, and the primary system manipulated variable P1 when P2 <0% or P2> 100% Is to invalidate this inappropriate operation amount as an inappropriate operation amount.

When P2 <0%, if the secondary system manipulated variable P2 is continuously output as it is, the power output continues to be 0%,
When P2> 100%, the power output continues to be 100%, which causes overshoot.
This is because the primary system manipulated variable P1 that gives the secondary system manipulated variable P2 is corrected and reset so that a more appropriate secondary system manipulated variable P2 can be obtained. That is, the primary system operation amount P1 (secondary system target value SV ') as the target value of the secondary system operation amount P2
Check that the electric power to the heater 3 is 0% or 10%.
It is intended to prevent the 0% condition from continuing.

The memory 5b is a memory for storing the primary system manipulated variable P1 which has been determined to be appropriate.
The secondary system operation amount P2 is within the operation range, that is, the primary system operation amount P1
Is determined to be appropriate, the primary system manipulated variable P1 stored in the memory 5a is stored as an appropriate primary system manipulated variable P1 '. Therefore, the content of the memory 5b is 1
Each time the secondary system manipulated variable P1 is judged to be appropriate, it is rewritten, and the latest primary system manipulated variable P1 that gives the secondary system manipulated variable P2 within the operable range is always the appropriate primary system. It is stored as the manipulated variable P1 '.

When the determination unit 6 determines that the secondary system operation amount P2 is within the operation range, the memory 5a is operated as described above.
The primary system manipulated variable P1 is used to update the contents of the memory 5b, the secondary system manipulated variable P2 is sent from the PID 2 to the heater 3, and the temperature of the heater 3 is controlled based on the power of the secondary system manipulated variable P2. It is supposed to do. As a normal operation, the primary system operation amount P1 is output from the memory 5a, and PI
D2 is the primary system manipulated variable P1 (secondary system target value SV ') and 2
The deviation E '(= SV'-PV') from the next system control amount PV 'is input and PID calculation is performed.

Then, in the judging section 6, the secondary system manipulated variable P
When it is determined that 2 is outside the operation range, that is, when the primary system operation amount P1 is determined to be inappropriate, the determination unit 6 sends a control signal to the memory 5b, and the primary system operation amount of the memory 5a. An appropriate primary system manipulated variable P1 'stored in the memory 5b is output instead of P1, and an appropriate primary system manipulated variable P1' (this becomes an appropriate secondary system target value SV ') is output to PID2. Between the secondary control amount PV 'and the secondary system control amount E' (= SV'-P
V ') is input.

From the memory 5b, an appropriate primary system manipulated variable P1 '
In the case of outputting, the PID calculation output X2 calculated by PID2 based on the appropriate primary system manipulated variable P1 'is converted into electric power without being checked by the determination unit 6 to obtain the secondary system manipulated variable P2. The secondary system operation amount P2 is output to the heater 3. Further, in this case, the memory 5b is not updated, and the value of the appropriate primary system operation amount P1 'remains unchanged.

In this way, the PID calculation output X calculated by PID2 with the primary system manipulated variable P1 as the secondary system target value SV '.
2 is not used as the secondary system manipulated variable P2 to control the heater 3, but whether the secondary system manipulated variable P2 calculated using the primary system manipulated variable P1 as a target value is within the operable range. Is determined by the determination unit 6, and whether or not the primary system manipulated variable P1 that has become the target value is appropriate is determined. If the primary system manipulated variable P1 is inappropriate, it is stored in the memory 5b in advance. By outputting the appropriate stored primary system manipulated variable P1 ', the secondary system manipulated variable P2 becomes unnecessarily large or small, and the secondary system manipulated variable P2 is supplied to the heater 3. It is possible to prevent the electric power from continuing the state of the minimum output of 0% and the maximum output of 100% and suppress the overshoot state of the temperature in the furnace 4 which is the primary control amount PV so that stable control characteristics can be obtained. There is.

Next, the control method of the control device of the semiconductor manufacturing apparatus of this embodiment will be specifically described with reference to the flowchart of FIG. First, the target value SV of the primary control system, which is the target temperature in the furnace 4, is input from the operation panel (101), the temperature in the furnace 4 is measured by the sensor using the thermocouple, and the input circuit Then, the primary system control amount PV is input as feedback (102), and the primary control system PI is input.
D processing (PID1) is performed (103). P of primary control system
The ID process (PID1) uses SV-PV as the deviation E,
PID calculation is performed in the primary calculation unit (PID1) 1,
The PID calculation output X1 is obtained (103).

The operation formula of the PID operation used in the control method of the control device of the semiconductor manufacturing apparatus of this embodiment is as shown in the following mathematical expressions, and each parameter is substituted into the mathematical expression to output the PID operation. It is to obtain X. here,
Multiplying each term in braces by a constant K, the first term is the output Xp by the proportional action, and the second term is the output X by the integral action.
The i and the third terms respectively correspond to the output Xd by the differential operation, and the PID calculation output X is calculated by the sum of them.

[0037]

[Equation 1]

PI of PID1 calculated in this way
The D operation output X1 is used as the primary system manipulated variable P1 in the memory 5a.
(104). Then, the primary system operation amount P1 is sent from the memory 5a to the secondary operation unit (PID2) 2 (10
5) Perform PID processing (PID2) of the secondary control system (1
06). The PID process (PID2) of the secondary control system is performed by the secondary system target value SV '(primary system operation amount P1) and the heater temperature fed back from the heater 3 (secondary system control amount PV').
From the deviation E (= SV'-PV '), PID calculation is performed to calculate the PID calculation output X2 (106), and PI
The D operation output X2 is converted into electric power and stored in the memory 5c as the electric power value of the secondary system manipulated variable P2 (107).

Next, in the judging section 6, the secondary system manipulated variable P
Whether 2 is within the operable range, that is, 0%
It is determined whether ≤P2 ≤100% (108), and 0
If% ≤P2≤100%, the primary system operation amount P1 is determined to be appropriate, and the control signal from the determination unit 6 causes the memory 5a to operate.
The primary system manipulated variable P1 stored in is read and written in the memory 5b as an appropriate primary system manipulated variable P1 ', and the content of the memory 5b is updated (109). As a result, the latest primary system manipulated variable P1 that gives the secondary system manipulated variable P2 within the operable range is set as the appropriate primary system manipulated variable P1 'in the memory 5b.
Will be stored in. Then, the secondary system operation amount P2 output from PID2 is sent to the heater 3 (12
0).

Further, in the judging section 6, the secondary system manipulated variable P
2 is outside the operable range, that is, P2 <0% or P2
When it becomes> 100% and it is determined that the primary system manipulated variable P1 is inappropriate, a proper primary system manipulated variable P1 ′ stored in the memory 5b is output by the control signal from the determination unit 6. (111). Then, the PID process (PID2) of the secondary system is performed based on the appropriate primary system manipulated variable P1 '(11
2). An appropriate primary system manipulated variable P1 'is an output value of the primary system manipulated variable when the secondary system manipulated variable P2 was within the previous operating range.

The PID processing (PID2) of the secondary system is to perform the PID computation with the appropriate primary system manipulated variable P1 'as the target value to compute the PID computation output X2. And
The PID operation output X2 is converted into electric power and the secondary system manipulated variable P2
Then (113), the secondary system operation amount P2 is output to the heater 3 (120).

By repeating the above operation by the cascade control system, the temperature of the furnace 4 which is the primary system control amount PV is made to approach the target value SV. In this way, the control method of the control device of the semiconductor manufacturing apparatus of this embodiment is performed.

Next, an example of control when the temperature of the heating furnace is actually controlled by using the control apparatus and control method for the semiconductor manufacturing apparatus of this embodiment is shown in FIG. 3, FIG. 4, and FIG. This will be described using a block diagram. First, in the state of FIG. 3, the temperature of the furnace 4 at the target value SV of the primary control system is 1000 ° C.
Against the measured temperature of the furnace 4 (primary system control amount PV)
Is 700 ° C., and the deviation E is 300 ° C. This one
If the result of inputting to the next operation unit (PID1) 1 and performing the PID operation and the PID operation output X1 being 1200 ° C. is obtained, this is set as the primary system operation amount P1 and stored in the memory 5a.
To store. Then, the secondary system target value SV 'is set to 1200 ° C.
Is sent to the secondary calculation unit (PID2). At this time, the measured value of the heater temperature (secondary system control amount PV ′) was 900 ° C., so the input deviation E ′ was 300 ° C.

Then, PID calculation is performed in the secondary calculation unit (PID2) 2 to calculate the PID calculation output X2, which is converted into electric power and output to the heater 3 as the secondary system manipulated variable P2. The power value of the secondary system manipulated variable P2 is stored. Here, it is assumed that the secondary system manipulated variable P2 is 95%.

Next, in the judging section 6, the secondary system manipulated variable P
It is determined whether 2 is 0% ≤P2≤100%. Here, the secondary system manipulated variable P2 is 95%, which satisfies the above condition. Then, according to the control signal from the determination unit 6, 1200 ° C. stored in the memory 5a is set to an appropriate value of 1 ° C.
It is written in the memory 5b as the next system operation amount P1 ', and the memory 5b is updated.

FIG. 4 is a schematic block diagram of the next stage of FIG. By the control of FIG. 3, the temperature of the furnace 4 is 900 ° C.
And the deviation E from the target value SV of the primary control system is 100
It became ℃. The primary system manipulated variable P1 calculated by PID1 is 1300 ° C., and this is stored in the memory 5a.
2 to the secondary system target value SV '. Assuming that the heater temperature at this time is 1000 ° C., the deviation E ′ becomes 300 ° C., and when the PID2 is calculated, the secondary system operation amount P2 becomes 120%, which is stored in the memory 5c.

Here, the operation amount P of the secondary system is determined by the determination unit 6.
If it is determined that P2 is greater than 100%, the determination unit 6 determines that the primary system operation amount P1 is inappropriate, sends a control signal to the memory 5b, and outputs an appropriate primary system operation amount from the memory 5b. P1 'is read and output to PID2. The appropriate primary system manipulated variable P1 'at this time is 12 as shown in FIG.
Since it is 00 ° C, the secondary system target value S for PID2
When V'is 1200 ° C. and deviation E'is 200 ° C. and PID calculation is performed, the secondary system manipulated variable P2 is 95%,
The electric power of the secondary system operation amount P2 is sent to the heater 3.

With the conventional control method, the secondary system manipulated variable P
When 2 is 120%, the maximum value of the operable range is 10
The output is 0%, and the heater 3 continues to be heated at full power. However, in this embodiment, unnecessary heating of the heater 3 is suppressed and the primary system control amount PV approaches the target value SV. In this case, the operation amount P2 of the secondary system is promptly reduced.

Next, the results of the control shown in FIG. 4 are shown in FIG.
Is shown in the schematic block diagram. The temperature of the furnace 4 is 1000
Suppose that the temperature E becomes 0 ° C., and the deviation E from the target value SV of the primary control system becomes 0 ° C., it is assumed that the primary system operation amount P1 becomes 1150 ° C. when the calculation is performed by PID1. This is set as the secondary system target value SV ', and the heater temperature (secondary system control amount P
V ') is 1200 ° C, the deviation E'is -50 ° C.
When input to ID2 and PID calculation is performed, the secondary system manipulated variable P
2 becomes 20%, and the temperature rise of the heater 3 is quickly suppressed.

Thus, for example, when the temperature in the furnace 4 which is the primary system control amount PV is raised to approach the target value SV, conventionally, the temperature in the furnace 4 is close to the target value SV. Even if the primary system manipulated variable P1 is calculated as a large value due to the I motion of PID1, the secondary system manipulated variable P2 is 10
Calculated over 0%, the power supplied to the heater 3 is 100
%, The heater temperature continues to rise, and as a result,
The temperature of the furnace 4 may exceed the target value in some cases, but in the present embodiment, the determining unit 6 is provided, and the determining unit 6 determines that the secondary system manipulated variable P2 exceeds 100%. Is corrected by resetting the primary system manipulated variable P1 to the value when it did not exceed 100% last time (appropriate primary system manipulated variable P1 '), and the secondary system manipulated variable P2 becomes 100%. The temperature is controlled so as not to exceed the upper limit to prevent the heater temperature from becoming too high, so that the secondary control system can quickly respond to changes in the primary system control amount PV.

According to this embodiment, the primary system manipulated variable P1 calculated by PID1 is set as P2 as the secondary system target value SV '.
When the secondary system manipulated variable P2 calculated by ID2 is output to the heater 3, it is determined whether the secondary system manipulated variable P2 is within the operable range, that is, whether 0% ≤P2≤100%. Is provided, and the secondary system manipulated variable P2 is 0% ≦ P2 ≦ 10.
If it is 0%, the primary system manipulated variable P1 is stored in the memory 5b as an appropriate primary system manipulated variable P1 ', and if the secondary system manipulated variable P2 is P2 <0% or P2> 100%. , A control device of a semiconductor manufacturing apparatus for obtaining a secondary system manipulated variable P2 by using an appropriate primary system manipulated variable P1 'already stored in the memory 5b as a secondary system target value SV', and sending it to the heater 3 and its control Since the secondary system manipulated variable P2 is always within the operable range, the temperature of the heater 3 is required when the temperature of the furnace 4 as the primary system controlled variable PV is about to exceed the target value SV. If the temperature inside the furnace 4 is about to fall below the target value SV, the heater 3
By resetting the primary system manipulated variable P1 to an appropriate primary system manipulated variable P1 'so that the temperature of does not drop excessively,
By increasing the response speed of the secondary control system to the change in the primary system control amount PV, the time until the temperature in the furnace 4 reaches the target value SV can be shortened, and the target value SV is reached. This has the effect of suppressing the overshooting state up to and achieving stable control characteristics.

[0052]

According to the first aspect of the present invention, it is determined whether or not the second manipulated variable output from the second computing unit is within a preset range. The appropriate operation amount stored as the appropriate operation amount in place of the first operation amount output from the arithmetic operation unit of the first operation amount is output to the second control system. Since the control method of the control device for the semiconductor manufacturing apparatus is the same, the second operation of the second control system is performed with the appropriate operation amount within the range as the second target value even if the second operation amount is out of the range. Since the PID calculation can be performed in the part and the second manipulated variable can be controlled so that it is always within the range, the temperature inside the furnace can be quickly stabilized to the target value, and stable temperature control is performed. There is an effect that can be.

According to the second aspect of the present invention, the determination unit reads the second operation amount output from the second calculation unit, determines whether it is within a preset range, and is within the range. Sometimes the first operation amount output from the first calculation unit is stored in the storage unit as an appropriate operation amount, and when it is out of the range, the first operation amount is stored.
The control device for the semiconductor manufacturing apparatus according to claim 1, wherein an appropriate amount of operation is output from the storage unit instead of the first amount of operation output from the calculation unit of the second operation amount. Even if an appropriate manipulated variable within the range is used as the second target value, PID computation can be performed by the second computing unit of the second control system, and the second manipulated variable is controlled so as to always fall within the range. Therefore, the temperature in the furnace can be quickly stabilized to a target value, and stable temperature control can be performed.

[Brief description of drawings]

FIG. 1 is a schematic configuration block diagram of a control device of a semiconductor manufacturing apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a control method of the control device of the semiconductor manufacturing apparatus according to the present embodiment.

FIG. 3 is a schematic configuration block diagram showing a control example in the control device of the semiconductor manufacturing apparatus of the present embodiment.

FIG. 4 is a schematic configuration block diagram showing a control example in a control device of the semiconductor manufacturing apparatus of the present embodiment.

FIG. 5 is a schematic configuration block diagram showing a control example in a control device of the semiconductor manufacturing apparatus of the present embodiment.

FIG. 6 is a schematic configuration block diagram of a control device of a conventional semiconductor manufacturing apparatus.

FIG. 7 is a flowchart showing the overall cascade control of a control device for a conventional semiconductor manufacturing apparatus.

FIG. 8 is a flowchart showing control of a primary control system of a conventional semiconductor manufacturing apparatus controller.

FIG. 9 is a flowchart showing the control of the secondary control system of the control device of the conventional semiconductor manufacturing apparatus.

[Explanation of symbols]

1 ... Primary operation unit, 2 ... Secondary operation unit, 3 ... Heater,
4 ... In the furnace, 5 ... Memory, 6 ... Judgment unit

Claims (2)

[Claims] 1. A heater for adjusting a temperature in a furnace, a first target value which is a target value of the temperature in the furnace, and a first controlled variable which is a temperature measured in the furnace. A first control system having a first calculation unit that performs a PID calculation to calculate a first operation amount, and a first operation amount calculated by the first calculation unit as a second target value, A second control system having a second calculation unit that performs a PID calculation based on the second target value and a second controlled variable that is the output temperature of the heater to calculate a second manipulated variable. In a control method of a control device for a semiconductor manufacturing apparatus connected to a cascade control system, it is determined whether or not the second manipulated variable output from the second computing unit is within a preset range, and the outside of the range is determined. If so, it is within the range instead of the first operation amount output from the first calculation unit. A method for controlling a control device of a semiconductor manufacturing apparatus, wherein an appropriate manipulated variable stored at the time of output is output to the second control system. 2. A determination unit that reads a second operation amount output from the second operation unit and determines whether the operation amount is within a preset range, and a first operation unit when the operation amount is within the range. A memory that stores the output first operation amount as an appropriate operation amount, and outputs the appropriate operation amount instead of the first operation amount output from the first calculation unit when the output value is out of the range. The control device for the semiconductor manufacturing apparatus according to claim 1, further comprising: