JP4477559B2 - Control apparatus and control method - Google Patents

Description

  The present invention relates to a process control technique, and more particularly to a control device and a control method for controlling at least two or more control amounts while switching appropriately.

  For example, in a bonding process in a semiconductor manufacturing process, temperature control with good reproducibility (temperature control without variation for each target product) is required. A specific example is a flip chip method. In this construction method, bumps are formed on a chip, and the chip is held by a tool so that the surface on which the bumps are formed faces down, and brought close to the electronic component mounting substrate. A pad is formed on the electronic component mounting substrate. After the bump is brought into contact (contact) with the pad, the chip bump is melted by the heat generated by the heater incorporated in the tool and bonded to the pad on the substrate. .

  In a normal bonding process, the temperature of a tool with a built-in heater for holding a chip (hereinafter referred to as a heater for the sake of simplification) is controlled to be as high as possible. In this control method, what is actually controlled is not the temperature of the pad on the electronic component mounting board (hereinafter referred to as an electronic component mounting board for the sake of simplicity), but the temperature of the heater. One reason for controlling the temperature of the heater is that it is difficult to measure the temperature (substance temperature) of the electronic component mounting board in real time. Moreover, it is also because it aimed at the substantial temperature becoming high temperature in a short time by maintaining a heater at high temperature. Therefore, even when the contact for bonding is not made, the heater needs to be maintained at a desired temperature, so that the heater temperature is continuously controlled.

  On the other hand, a method of estimating and controlling the actual temperature when the actual temperature cannot be measured has been proposed. For example, in the semiconductor manufacturing apparatus disclosed in Patent Document 1, the wafer temperature is estimated, and the power supplied to the heater provided on the hot plate on which the wafer is placed is controlled based on the estimated value of the wafer temperature. If the actual temperature estimated value control represented by the method of Patent Document 1 is applied, it can be predicted that even in the bonding process, temperature control without variation for each target product can be achieved at a high level.

JP 2000-235944 A

  The semiconductor manufacturing apparatus disclosed in Patent Document 1 adopts a method of heating a wafer placed on a hot plate, and basically performs temperature control consistently based on the estimated wafer temperature value. Therefore, when the wafer is not placed, the heater output of the hot plate is off.

  On the other hand, in the bonding step, the temperature of the electronic component mounting substrate is increased by bringing the heater into contact with the electronic component mounting substrate while maintaining the temperature at a high temperature. When the technique disclosed in Patent Document 1 is applied to such a bonding process, the heater 100 is heated to a high temperature while the heater 100 is not in contact with the electronic component mounting substrate 101 as shown in FIG. After the heater 100 is in contact with the electronic component mounting board 101 as shown in FIG. 4 (C), the temperature (substance temperature) of the electronic component mounting board 101 is estimated. The power supplied to the heater 100 is controlled so that the actual temperature becomes a desired value. FIG. 4B shows the temperature to be controlled before the heater 100 contacts the electronic component mounting board 101, that is, the heater temperature. FIG. 4D shows the heater 100 contacting the electronic component mounting board 101. This indicates that the temperature of the control target is switched from the heater temperature to the actual temperature.

  However, in the temperature control in which the technique of Patent Document 1 is applied to the bonding process, there is a large temperature difference between the heater temperature maintained at a high temperature and the actual temperature before the temperature rise. There is a problem that the target temperature is suddenly lowered apparently, the control operation becomes discontinuous, and the control characteristics deteriorate. For example, when PID is used for the control calculation of the controller, the controller suddenly increases the manipulated variable MV as shown in FIG. 5B in response to the rapid decrease in the temperature to be controlled as shown in FIG. This rapid increase in the manipulated variable MV makes it difficult to raise the temperature of the electronic component mounting board with good characteristics.

  Another reason why the temperature control using the technique of Patent Document 1 in the bonding process cannot obtain a good temperature rise characteristic is different from the control in which the temperature rises from the normal settling state, and the temperature rise from the non-settling state. There is a point that it becomes operation. In the case of temperature control in which the technique of Patent Document 1 is applied to the bonding process, the operation amount MV (20% in the example of FIG. 6B) output from the controller before the heater contacts the electronic component mounting board is the heater. This is an operation amount for setting the temperature to 200 ° C., not an operation amount for setting the temperature of the electronic component mounting board. Here, when the heater comes into contact with the electronic component mounting board and the temperature to be controlled is switched from the heater temperature to the temperature (substance temperature) of the electronic component mounting board, the manipulated variable MV suddenly increases as shown in FIG. Although the change in the manipulated variable MV is abrupt and too large, the power supplied to the heater is excessively increased, and the substantial temperature is equal to the ideal substantial temperature represented by the broken line in FIG. Showing different trajectories. That is, the temperature raising operation represented by the solid line in FIG. 6A is substantially the same phenomenon as the temperature is disturbed by the operation amount MV having an inappropriate value output from the controller.

  As described above, the temperature control in which the technique of Patent Document 1 is applied to the bonding process has an advantage that a substantial temperature that is difficult to measure can be estimated and variation in temperature control among products can be suppressed. However, there is a problem that good control characteristics cannot be obtained when the temperature to be controlled is switched. The above problems are not limited to the bonding process, and the technique disclosed in Patent Document 1 is applied to other process control. When the operation unit such as a heater has not started an operation on the control target, the output amount of the operation unit is reduced. The same occurs when the control amount is switched from the output amount of the operation unit to the estimated value of the physical amount of the control target at the time when the operation unit starts an operation on the control target.

  The present invention has been made to solve the above-described problem. In the first control period in which the operation unit does not operate the control target, the output amount of the operation unit is set as the control amount, and the operation unit operates the control target. In the control period, when the estimated value of the physical quantity to be controlled is used as the control quantity, the control quantity follows the set value with good characteristics when switching from the first control period to the second control period. It is an object of the present invention to provide a control device and a control method that can be controlled.

In the first control period in which the operation unit does not operate the control target, the temperature of the operation unit is set as a first control amount, and the control target is controlled in the second control period in which the operation unit operates the control target. The control device switches the control amount using the temperature of the second control amount as the second control amount, and when the first control period is switched to the second control period, the first control amount is the second control amount. The operation unit, a first set value input unit for acquiring a first set value for the first control amount, and a first for acquiring the first control amount are maintained at a temperature higher than the amount . A control amount input unit; a second set value input unit that acquires a second set value for the second control amount; a second control amount input unit that acquires the second control amount; when the operation unit starts the operation of raising the temperature by contact with the control target A switching unit that switches from the first control period to the second control period; and a filtering setting value obtained by filtering the second setting value by a first-order lag calculation in the second control period; When switching from the first control period to the second control period, in the first control period, a set value filter unit that uses the second control amount at the time of switching as the initial value of the filtering set value; Calculates an operation amount to be output to the operation unit by PID control calculation based on the first control amount and the first set value, and the second control amount and the filtering are calculated in the second control period. A control calculation unit that calculates the manipulated variable by PID control calculation based on a set value; and when the control is switched from the first control period to the second control period, the control The PID control calculation is performed so that the state of the PID control calculation by the arithmetic unit is equivalent to the state set by the manipulated variable at the switching point, the second control amount at the switching point, and the filtering setting value at the switching point. And a reset execution unit that resets the past control deviation and the amount of change in the past control deviation to zero, and the filter time constant of the first-order lag calculation is a heat transfer from the operation unit maintained at a high temperature. When the second control amount rises, the speed at which the filtering set value converges to the second set value is designed to be approximately equal to the speed at which the second control amount rises. It is a feature .

In addition, one configuration example of the control device of the present invention further includes an estimation unit that estimates an estimated value of the temperature of the control target as the second control amount, the operation unit is a heater, and the control target Is an electronic component mounting board, the first control amount is a temperature of the heater, the second control amount is a temperature estimated value of the electronic component mounting board, and the switching unit is When the heater contacts the electronic component mounting board, the heater is switched from the first control period to the second control period.
Further, one configuration example of the control device of the present invention further includes an estimation unit that estimates an estimated value of the temperature of the control target as the second control amount, the operation unit is a hot plate, and the control The object is a semiconductor wafer, the first control amount is the temperature of the hot plate, the second control amount is an estimated temperature value of the semiconductor wafer, and the switching unit is the semiconductor wafer. Is switched from the first control period to the second control period when placed on the hot plate.

In the first control period in which the operation unit does not operate the control target , the present invention sets the temperature of the operation unit as a first control amount, and in the second control period in which the operation unit operates the control target, A control method for switching a control amount using a temperature to be controlled as a second control amount, and when switching from the first control period to the second control period, the first control amount is the second control amount. A first set value input procedure for obtaining a first set value for the first control amount, and a first control amount for obtaining the first control amount. An input procedure; a second set value input procedure for acquiring a second set value for the second control amount; a second control amount input procedure for acquiring the second control amount; when starting the operation of raising the temperature by contact with the control target A switching procedure for switching from the first control period to the second control period, and a filtering setting value obtained by filtering the second setting value by a first-order lag calculation in the second control period; When switching from the first control period to the second control period, in the first control period, a set value filtering procedure using the second control amount at the time of switching as the initial value of the filtering set value; Calculates an operation amount to be output to the operation unit by PID control calculation based on the first control amount and the first set value, and the second control amount and the filtering are calculated in the second control period. A control calculation procedure for calculating the manipulated variable by a PID control calculation based on a set value, and when switching from the first control period to the second control period, The PID control calculation state according to the control calculation procedure is equivalent to a state in which the operation amount at the switching time, the second control amount at the switching time, and the filtering setting value at the switching time are set. And a reset execution procedure for resetting the past control deviation in the control computation and the amount of change in the past control deviation to zero, and the filter time constant of the first-order lag computation is the heat of the operation unit maintained at a high temperature. When the second control amount increases due to transmission, the speed at which the filtering set value converges to the second set value is designed to be approximately equal to the speed at which the second control amount increases. It is characterized by .

  ADVANTAGE OF THE INVENTION According to this invention, the temperature of the control object difficult to measure can be estimated, and the dispersion | variation in the temperature control for every product can be suppressed. In the present invention, at the moment when the control amount is switched from the first control amount to the second control amount, the state of the control calculation by the control calculation unit is the operation amount at the time of switching and the second control amount at the time of switching. The variable related to the past control amount in the control calculation is reset so as to be equivalent to the state set at the setting value at the time of switching, and the filtering setting value used for the control calculation in the second control period is originally aimed. Since it gradually approaches the second set value, it is possible to control the second control amount to follow the second set value with good characteristics when the control amount is switched. It becomes.

[Principle of the Invention]
In the present invention, in the non-settling state at the time when the control amount PV to be controlled is switched, an excessive control operation is added as a result of a normal control calculation as a cause of the above-described problem. Pay attention. Therefore, in the present invention, when the control amount PV to be controlled is switched, in order to prevent an excessive control operation from being applied, the control calculation inside the controller is performed when the control amount PV to be controlled is switched. The controller internal state is maintained so as to maintain the operation amount MV at, and the state is gradually approached to a state where the original control target is achieved.

  In order to generate a controller internal state in which the control calculation inside the controller maintains the operation amount MV at the time when the control amount PV to be controlled is switched, the state of the control calculation inside the controller is the operation at the time of switching. The variables related to the past control amount PV in the control calculation are reset so as to be equivalent to the state set by the amount MV, the control amount PV_cur at the time of switching, and the set value SP = PV_cur at the time of switching.

  For example, when PID is used for the control calculation, at the time of switching the control amount PV, the past control deviation and the change amount of the past control deviation are reset to zero, and the set value SP is set to SP = PV_cur. At the same time, the manipulated variable MV_cur at the time when the controlled variable PV to be controlled is switched to the previous value. This is substantially equivalent to the situation where the set value SP = PV_cur, the controlled variable PV = PV_cur (that is, SP = PV = PV_cur), and the manipulated variable MV = MV_cur before the controlled variable PV to be controlled is switched. become.

  Next, in order to gradually approach the state where the original control target is achieved from the state at the time of switching, the set value SP is gradually approached from SP = PV_cur to the value originally intended. . As a method for realizing such a process, for example, a method of applying a first-order lag filtering process to a value that should be originally aimed so that the set value SP gradually approaches the value that should be originally aimed can be considered. It is done.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a control device according to the first embodiment of the present invention, and FIG. 2 is a flowchart showing the operation of the control device of FIG. The control device according to the present embodiment obtains a first set value SP1 input unit 1 for obtaining a first set value SP1 for the first control amount PV1, and a second set value SP2 for the second control amount PV2. The second set value SP2 input unit 2 to be acquired, the first control amount PV1 input unit 3 to acquire the first control amount PV1, and the second control amount PV2 input unit to acquire the second control amount PV2. 4, an operation amount MV output unit 5 that outputs an operation amount MV, an operation unit 6 that performs an operation according to the operation amount MV with respect to a control target, a PID controller 7 that executes a PID control calculation, and an operation unit 6 A first PID parameter storage unit 8 that stores in advance a first PID parameter for a first control period during which the control target is not operated, and a second control period for which the operation unit 6 operates the control target Pre-store the second PID parameter PID parameter storage unit 9, control amount switching signal input unit 10 that receives a control amount switching signal when switching from the first control period to the second control period, and switching time control that stores switching time control amount PV_cur An amount PV_cur storage unit 11, a switching operation amount MV_cur storage unit 12 for storing the switching operation amount MV_cur, and a filtering setting value SP ′ obtained by filtering the second setting value SP2 in the second control period are generated. When switching from the first control period to the second control period, the set value SP filter unit 13 having the switching control amount PV_cur as the initial value of the filtering set value SP ′, and the first control period to the second control period. When the control period is switched, the reset execution unit 14 that resets the past control deviation and the change amount of the past control deviation to zero and the second control amount PV2 are estimated. And a estimation unit 15. The PID controller 7 constitutes a control calculation unit, and means (not shown) for causing the operation unit 6 to start an operation on the controlled object and the control amount switching signal input unit 10 are switched from the first control period to the second control period. A switching unit is configured.

  1, from the first control period in which the control is performed with the first control amount PV1 as the control target, to the second control period in which the control is performed with the second control amount PV2 as the control target. The operation when switching is described with reference to FIG. In order to simplify the description, a case where a digital controller having a control cycle of 1 second is realized by a computer will be described.

First, in the first control period, the first set value SP1 input unit 1 acquires the first set value SP1 set by the operator of the control device and outputs it to the PID controller 7 (step S1 in FIG. 1). .
The first control amount PV1 input unit 3 acquires the first control amount PV1 detected by the first detection means (not shown) and outputs it to the PID controller 7 (step S2). The first control amount PV1 is an output amount of the operation unit 6. Therefore, when the operation unit 6 is a heater, for example, the first control amount PV1 is the temperature of the heater, the first detection means is a temperature sensor, and the first set value SP1 is the temperature set value of the heater. .

Next, the PID controller 7 includes the first set value SP1 output from the first set value SP1 input unit 1, the first control amount PV1 output from the first control amount PV1 input unit 3, and the first set value SP1. On the basis of the first PID parameters (proportional band Pb1, integration time Ti1, differential time Td1) stored in advance in one PID parameter storage unit 8, PID control calculation as shown in the following equation is performed, and the manipulated variable MV Calculate and output to the manipulated variable MV output unit 5 (step S3).
MV = MV ′ + MD (1)
MD = (100 / Pb1) {EP + (ER / Ti1) + Td1ED} (2)

In equations (1) and (2), MV ′ is the operation amount before one control cycle, MD is the operation amount update amount, ER is the control deviation of the current control cycle, and EP is the change of the control deviation ER per control cycle. The amount, ED, is a change amount per control cycle of the control deviation change amount EP. The control deviation ER, the control deviation change amount EP, and the change amount ED of the control deviation change amount EP are respectively obtained by the following equations.
ER = SP1-PV1 (3)
EP = ER−ER ′ (4)
ED = EP−EP ′ (5)
ER ′ is a control deviation before one control cycle, and EP ′ is a control deviation change amount before one control cycle. Then, the PID controller 7 updates ER ′, EP ′, and MV ′ as follows for the calculation of the next control cycle.
ER '= ER (6)
EP ′ = EP (7)
MV ′ = MV (8)

The PID controller 7 sets the operation amount MV = OL when the calculated operation amount MV is smaller than the predetermined operation amount lower limit value OL, and sets the operation amount when the calculated operation amount MV is larger than the predetermined operation amount upper limit value OH. The manipulated variable MV is output after performing the manipulated variable upper and lower limit processing with MV = OH.
The operation amount MV output unit 5 outputs the operation amount MV output from the PID controller 7 to the operation unit 6 (step S4). The operation unit 6 operates based on the operation amount MV.

  Next, the control amount switching signal input unit 10 instructs to switch the control amount PV from the output amount of the operation unit 6 to the physical amount to be controlled (that is, switch from the first control period to the second control period). It is determined whether or not a control amount switching signal is input (step S5). If the control amount switching signal is not input, the process returns to step S1. Thus, until the control amount switching signal is input, the control in steps S1 to S4 in which the output amount of the operation unit 6 is the first control amount PV1 is repeated every control cycle.

  Further, when a control amount switching signal is input from the outside, the control amount switching signal input unit 10 outputs the control amount switching signal to the first set value SP1 input unit 1, the second set value SP2 input unit 2, A first control amount PV1 input unit 3, a second control amount PV2 input unit 4, a PID controller 7, a switching control amount PV_cur storage unit 11, a switching operation amount MV_cur storage unit 12, a set value SP filter unit 13, and Transfer to the reset execution unit 14.

  The control amount switching signal may be manually input by the operator of the control device when the operation unit 6 starts an operation on the control target, or means for causing the operation unit 6 to start an operation on the control target (for example, the operation unit When 6 is a heater and the control target is an electronic component mounting board, a control amount switching signal may be automatically sent from a driving device that brings the heater into contact with the electronic component mounting board.

The first set value SP1 input unit 1 and the first control amount PV1 input unit 3 that have received the control amount switching signal stop the output of the first set value SP1 and the first control amount PV1, and the control device This process is switched to the second control period after step S6.
The second set value SP2 input unit 2 that has received the control amount switching signal acquires the second set value SP2 set by the operator of the control device and outputs it to the set value SP filter unit 13 (step S6).

  For example, the estimation unit 15 estimates the second control amount PV2 based on the first control amount PV1. Note that the estimation unit 15 sets a predetermined value (for example, the ambient temperature when the control target is an electronic component mounting board) as the initial value of the second control amount PV2 in the control cycle in which the control amount switching signal is received.

  The second control amount PV2 input unit 4 that has received the control amount switching signal acquires the second control amount PV2 estimated by the estimation unit 15 and outputs it to the PID controller 7 and the switching control amount PV_cur storage unit 11. (Step S7). The second control amount PV2 is an estimated value of the physical quantity to be controlled. Therefore, when the control target is an electronic component mounting board, the second control amount PV2 is an estimated temperature value of the electronic component mounting board, and the second set value SP2 is a set value with respect to the estimated temperature value of the electronic component mounting board. is there.

The switching control amount PV_cur storage unit 11 that has received the control amount switching signal stores the second control amount PV2 output from the second control amount PV2 input unit 4 as the switching control amount PV_cur (step S8).
The switching operation amount MV_cur storage unit 12 that has received the control amount switching signal stores the operation amount MV output one control cycle before as the switching operation amount MV_cur (step S9).

  The reset execution unit 14 that has received the control amount switching signal resets the control deviation ER ′ one control cycle before to zero (ER ′ = 0) and resets the control deviation change amount EP ′ one control cycle before to zero. Then, the reset control deviation ER ′ and the control deviation change amount EP ′ are output to the PID controller 7 (step S10).

The setting value SP filter unit 13 that has received the control amount switching signal uses the switching time control amount PV_cur stored in the switching time control amount PV_cur storage unit 11 as an initial value of the filtering setting value SP ′ after the control amount switching. (Step S11).
SP ′ = PV_cur (9)
In the current control cycle in which the control amount switching signal is input, the set value SP filter unit 13 does not use the second set value SP2. Further, the set value SP filter unit 13 sets the initial value SP ″ of the filtering set value one control cycle before as follows for the calculation of the next control cycle.
SP "= PV_cur (10)

The PID controller 7 that has received the control amount switching signal, the filtering set value SP ′ output from the set value SP filter unit 13, the second control amount PV2 output from the second control amount PV2 input unit 4, The operation amount MV_cur at the time of switching stored in the operation amount MV_cur storage unit 12 and the second PID parameters (proportional band Pb2, integration time Ti2, differentiation time Td2) stored in advance in the second PID parameter storage unit 9 Based on this, a PID control calculation such as the following equation is performed to calculate an operation amount MV and output it to the operation amount MV output unit 5 (step S12).
MV = MV_cur + MD (11)
MD = (100 / Pb2) {EP + (ER / Ti2) + Td2ED} (12)

The control deviation ER of the current control cycle is obtained as follows.
ER = SP′−PV2 (13)
The control deviation change amount EP of the current control cycle and the change amount ED of the control deviation change amount EP can be obtained by the above formulas (4) and (5). The control deviation ER ′ and the control deviation change amount EP ′ one control cycle before are values reset by the reset execution unit 14. After calculating ER, EP, ED, and MV, the PID controller 7 sets ER ′, EP ′, and MV ′ to the equations (6), (7), and ( Update as in 8).

The PID controller 7 outputs the operation amount MV after performing the operation amount upper / lower limit processing as described above.
The operation amount MV output unit 5 outputs the operation amount MV output from the PID controller 7 to the operation unit 6 (step S13).

Next, the operation of the control device proceeds from the control cycle (hereinafter referred to as the first control cycle) in which the control amount switching signal is input to the next control cycle (hereinafter referred to as the second control cycle).
The process of the second set value SP2 input unit 2 in step S14 is the same as that in step S6, and the process of the second control amount PV2 input unit 4 in step S15 is the same as in step S7.

Based on the second setting value SP2 output from the second setting value SP2 input unit 2, the setting value SP filter unit 13 calculates the filtering setting value SP ′ by the following expression and outputs the calculated value to the PID controller 7 ( Step S16).
SP ′ = (SP ″ Tsp + SP2) / (Tsp + 1) (14)
In Expression (14), Tsp is a preset SP filter time constant, and SP ″ is a filtering setting value before one control cycle. SP ″ in the second control cycle is the first control after switching the control amount. This is the initial value of the filtering set value set by the set value SP filter unit 13 in the cycle. After calculating the filtering set value SP ′, the set value SP filter unit 13 updates SP ″ as follows for the calculation of the next control cycle.
SP ″ = SP ′ (15)

The PID controller 7 includes a filtering set value SP ′ output from the set value SP filter unit 13, a second control amount PV 2 output from the second control amount PV 2 input unit 4, and a second PID parameter storage unit 9. Based on the second PID parameter stored in advance, a PID control calculation such as the following equation is performed to calculate the operation amount MV and output it to the operation amount MV output unit 5 (step S17).
MV = MV ′ + MD (16)
MD = (100 / Pb2) {EP + (ER / Ti2) + Td2ED} (17)

  The manipulated variable MV ′ before one control cycle is a value stored in the PID controller 7 in the immediately preceding control cycle (the first control cycle when the current control cycle is the second control cycle). is there. The control deviation ER of the current control cycle can be obtained by the above equation (13). Further, the control deviation change amount EP and the control deviation change amount EP ED of the current control cycle can be obtained by the above equations (4) and (5). After calculating ER, EP, ED, and MV, the PID controller 7 sets ER ′, EP ′, and MV ′ to the equations (6), (7), and ( Update as in 8).

The PID controller 7 outputs the operation amount MV after performing the operation amount upper / lower limit processing as described above.
The operation amount MV output unit 5 outputs the operation amount MV output from the PID controller 7 to the operation unit 6 (step S18).

  The processes in steps S14 to S18 as described above are repeatedly executed for each control cycle until the end of control is instructed by an operator (Yes in step S19), for example. In addition, after the third control period after the second control period, the SP ″ used by the set value SP filter unit 13 is equal to the filtering set value SP ′ calculated in the immediately preceding control period by the set value SP filter unit 13. It will be remembered.

  As described above, in the present embodiment, at the moment when the control amount is switched from the first control amount PV1 to the second control amount PV2, the state of the control calculation by the PID controller 7 is switched to the switching operation amount MV_cur. The variable related to the past control amount in the control calculation is reset so as to be equivalent to the state set by the time control amount PV_cur and the switching set value SP = PV_cur, and further used for the control calculation in the second control period. Since the filtering set value SP ′ is gradually brought closer to the second set value SP2 that should originally be aimed, the second set value PV2 has a good characteristic when the control amount is switched. It is possible to control to follow SP2.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the present embodiment, the first embodiment will be described more specifically, and the control device of the first embodiment is applied to the bonding process of the semiconductor manufacturing process. That is, the heater serves as the operation unit 6 and an electronic component mounting board (hereinafter referred to as an LCD board) is a control target. Thus, the heater temperature measurement value PVH becomes the first control amount PV1, the LCD substrate temperature estimated value PVD becomes the second control amount PV2, the set value SPH for the heater temperature becomes the first set value SP1, and the LCD substrate temperature The set value SPD for the estimated value becomes the second set value SP2, and the heater input MVH becomes the manipulated variable MV.

  First, before the bonding target LCD substrate is supplied to the work area, the heater temperature measurement value PVH is controlled as the control target temperature by the processing in steps S1 to S4 in FIG. 2, for example, heater input MVH = 20%. Thus, the heater temperature measurement value PVH is maintained at 200 ° C.

Next, when the LCD substrate is supplied to the work area, the estimation unit 15 sets the ambient temperature (room temperature 25 ° C.) as the initial value of the LCD substrate temperature estimated value PVD.
When the LCD substrate is supplied to the work area and the heater comes into contact with the LCD substrate, a control amount switching signal is input to the control amount switching signal input unit 10 from, for example, a driving device that lowers the heater.

  Due to the input of the control amount switching signal, the switching-time control amount PV_cur storage unit 11 stores the initial value PVD = 25 ° C. of the LCD substrate temperature estimated value as the switching-time control amount PV_cur (step S8). The amount MV_cur storage unit 12 stores the heater input MVH = 20% as the switching operation amount MV_cur (step S9).

The reset execution unit 14 resets the control deviation ER ′ one control cycle before to zero and resets the control deviation change amount EP ′ one control cycle before to zero (step S10).
The set value SP filter unit 13 sets the switching control amount PV_cur = 25 ° C. stored in the switching control amount PV_cur storage unit 11 as the initial value of the filtering set value SP ′ (step S11). Here, it is assumed that a set value SPD = 175 ° C. for the estimated LCD substrate temperature is given as an actual control target.

The PID controller 7 performs the PID control calculation in step S12 in the first control cycle after switching the control target temperature (control amount), and performs the PID control calculation in step S17 after the second control cycle.
After the second control period, the estimation unit 15 calculates an LCD substrate temperature estimated value PVD using a predesigned LCD substrate temperature estimation model such as the following equation.
PVD = (PVD′Tpv + PVH) / (Tpv + 1) (18)
Tpv is a time constant of heat transfer from the heater, and PVD ′ is an estimated LCD substrate temperature before one control cycle. However, in the expression (18), the control cycle is 1 second.

  Thus, the heater input MVH is calculated by the PID controller 7 using the initial value 25 ° C. of the filtering set value SP ′ and the initial value 25 ° C. of the LCD substrate temperature estimated value PVD as the control initial values, and the heater corresponding to the heater input MVH is calculated. Due to this heat generation, the LCD substrate temperature estimated value PVD rises. After the second control cycle, the LCD substrate temperature estimated value PVD rises in a form that follows the filtering set value SP ′ calculated by the set value SP filter unit 13. Eventually, the filtering set value SP ′ converges to 175 ° C. which is the same as the second set value SPD, that is, the LCD substrate temperature estimated value PVD rises to 175 ° C.

  In the present embodiment, at the moment when the control target temperature is switched to the LCD substrate temperature estimated value PVD, all of the control calculations by the PID controller 7 are performed by the heater input MVH having the same value as the heater input MVH at the time of the switching. Since the estimated value PVD is in a state equivalent to the situation where the set value SP ′ is set to 25 ° C., the heater input MVH does not increase rapidly at the moment when the temperature to be controlled is switched, and the temperature rises excessively. Does not occur. After the control target temperature is switched, the LCD substrate temperature estimated value PVD rises in a short time due to the transfer of heat from the heater maintained at a high temperature, but the filtering set value SP ′ also reaches the original set value SPD = 175 ° C. Converge.

  As shown in FIG. 3A, the SP filter is set so that the speed at which the filtering set value SP ′ converges to the original set value SPD = 175 ° C. is substantially equal to the speed at which the LCD substrate temperature estimated value PVD rises. If the time constant Tsp is designed, the control deviation ER = SP′−PVD calculated by the PID controller 7 changes without changing to a large value. As a result, the heater input MVH fluctuates only for the LCD substrate temperature estimated value PVD to follow the set value SP 'cleanly without excessively increasing as shown in FIG. That is, the heater input MVH is not limited by the upper / lower limit process of the operation amount of the PID controller 7, and the heater input MVH does not move up and down rapidly in a short time. SP ′ can be surely followed, and as a result, good control characteristics (temperature rise orbit) can be obtained.

  Although not described in the first embodiment, when a predetermined time elapses after the heater contacts the LCD substrate, the drive device raises the heater so that the heater is separated from the LCD substrate. At this time, when the control amount switching signal is input from the drive device to the control amount switching signal input unit 10, the temperature to be controlled is switched from the LCD substrate temperature estimated value PVD to the heater temperature measured value PVH.

In the present embodiment, the example in which the control device of the first embodiment is applied to the bonding process has been described. However, the present invention is not limited to this. For example, a low-temperature semiconductor is formed on a hot plate controlled to a high temperature. The same procedure can be applied to the case where the temperature of the wafer temperature estimated value is controlled by placing the wafer. That is, at the moment when the semiconductor wafer is placed on the hot plate, the control target temperature may be switched from the hot plate temperature measurement value to the wafer temperature estimation value. Moreover, if it is the same application, it will not be restricted to these.
In the first and second embodiments, the estimated value of the physical quantity to be controlled is used as the second control quantity, but the measured value of the physical quantity may be used. When the measured value of the physical quantity is used, the estimation unit 15 is not necessary.

  The control device described in the first and second embodiments can be realized by a computer having a CPU, a storage device, and an interface, and a program for controlling these hardware resources. The CPU executes the processing described in the first and second embodiments in accordance with a program stored in the storage device.

  The present invention can be applied to a process control technique.

It is a block diagram which shows the structure of the control apparatus used as the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of the control apparatus of FIG. It is a figure which shows one example of the control object temperature, the filtering set value, and the change of a heater input when a heater is made to contact an electronic component mounting board in the control apparatus of the 2nd Embodiment of this invention. It is a figure for demonstrating the temperature control which applied the technique of patent document 1 to the bonding process of a semiconductor manufacturing process. It is a figure for demonstrating the problem of the temperature control which applied the technique of patent document 1 to the bonding process of a semiconductor manufacturing process. It is a figure for demonstrating the problem of the temperature control which applied the technique of patent document 1 to the bonding process of a semiconductor manufacturing process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... 1st setting value SP1 input part, 2 ... 2nd setting value SP2 input part, 3 ... 1st control amount PV1 input part, 4 ... 2nd control amount PV2 input part, 5 ... Manipulation amount MV output , 6 ... operation unit, 7 ... PID controller, 8 ... first PID parameter storage unit, 9 ... second PID parameter storage unit, 10 ... control amount switching signal input unit, 11 ... switching time control amount PV_cur storage unit , 12 ... switching operation amount MV_cur storage unit, 13 ... set value SP filter unit, 14 ... reset execution unit, 15 ... estimation unit.

Claims (4)

In the first control period in which the operation unit does not operate the control target, the temperature of the operation unit is set as the first control amount, and in the second control period in which the operation unit operates the control target, the temperature of the control target is set to the first control amount. A control device that switches a control amount as a control amount of 2.
When switching from the first control period to the second control period, the first control amount is maintained at a higher temperature than the second control amount;
The operation unit;
A first set value input unit for acquiring a first set value for the first control amount;
A first control amount input unit for acquiring the first control amount;
A second set value input unit for acquiring a second set value for the second control amount;
A second control amount input unit for acquiring the second control amount;
A switching unit that switches from the first control period to the second control period when the operation unit starts an operation of raising the temperature by contacting the control target;
In the second control period, a filtering setting value obtained by filtering the second setting value by first-order lag calculation is generated, and this switching is performed when switching from the first control period to the second control period. A set value filter unit having the second control amount at the time as an initial value of the filtering set value;
In the first control period, an operation amount to be output to the operation unit is calculated by a PID control calculation based on the first control amount and the first set value, and in the second control period, the first control amount is calculated. A control calculation unit that calculates the operation amount by PID control calculation based on the control amount of 2 and the filtering setting value;
When switching from the first control period to the second control period, the state of the PID control calculation by the control calculation unit is the operation amount at the switching time, the second control amount at the switching time, and the switching. A reset execution unit that resets the past control deviation in the PID control calculation and the amount of change in the past control deviation to zero so as to be equivalent to the state that is set at the filtering setting value at the time ,
The filter time constant of the first-order lag calculation is such that the filtering set value converges to the second set value when the second control amount increases due to heat transfer from the operation unit maintained at a high temperature. A control device , wherein the speed and the speed at which the second control amount increases are designed to be substantially equal . The control device according to claim 1,
Furthermore, an estimation unit that estimates an estimated value of the temperature of the control target as the second control amount is provided,
The operation unit is a heater,
The control object is an electronic component mounting board,
The first control amount is a temperature of the heater;
The second control amount is an estimated temperature value of the electronic component mounting board,
The control unit, wherein the switching unit switches from the first control period to the second control period when the heater contacts the electronic component mounting board. The control device according to claim 1,
Furthermore, an estimation unit that estimates an estimated value of the temperature of the control target as the second control amount is provided,
The operation unit is a hot plate,
The control object is a semiconductor wafer,
The first control amount is a temperature of the hot plate,
The second control amount is an estimated temperature value of the semiconductor wafer,
The switching device switches from the first control period to the second control period when the semiconductor wafer is placed on the hot plate. In the first control period in which the operation unit does not operate the control target, the temperature of the operation unit is set as the first control amount, and in the second control period in which the operation unit operates the control target, the temperature of the control target is set to the first control amount. A control method for switching a control amount as a control amount of 2,
When switching from the first control period to the second control period, the first control amount is maintained at a higher temperature than the second control amount;
A first set value input procedure for obtaining a first set value for the first control amount;
A first control amount input procedure for acquiring the first control amount;
A second set value input procedure for obtaining a second set value for the second control amount;
A second control amount input procedure for acquiring the second control amount;
A switching procedure for switching from the first control period to the second control period when the operation unit starts an operation of raising the temperature by contacting the control target;
In the second control period, a filtering setting value obtained by filtering the second setting value by first-order lag calculation is generated, and this switching is performed when switching from the first control period to the second control period. A set value filtering procedure in which the second control amount at the time is the initial value of the filtering set value;
In the first control period, an operation amount to be output to the operation unit is calculated by a PID control calculation based on the first control amount and the first set value, and in the second control period, the first control amount is calculated. A control calculation procedure for calculating the manipulated variable by a PID control calculation based on the control amount of 2 and the filtering setting value;
When switching from the first control period to the second control period, the state of the PID control calculation by the control calculation procedure is the operation amount at the switching time, the second control amount at the switching time, and the switching. A reset execution procedure for resetting the past control deviation in the PID control calculation and the amount of change in the past control deviation to zero so as to be equivalent to a state where the set value is set with the filtering setting value at the time point ,
The filter time constant of the first-order lag calculation is such that the filtering set value converges to the second set value when the second control amount increases due to heat transfer from the operation unit maintained at a high temperature. A control method, wherein the speed and the speed at which the second control amount increases are designed to be substantially equal .

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