JPH09253564A - Resist applying device and resist applying method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the change in a resist supplying rate and to avert the occurrence of defective articles by the clogging of a filter. SOLUTION: The displacement quantity of a bellows pump 2 is detected by a laser displacement sensor 7 at the time of discharging a resist liquid from this bellows pump 2. The bellows displacement information Xs outputted from this sensor 7 and a preset bellows displacement set value Xr are then compared in a working stop comparing section 14. The moving direction of the shaft 3c of an air cylinder 3 is then inverted when Xr<=Xs is attained. A clogging deciding section 13 detects the time until Xr<=Xs is attained and outputs an alarm signal Alarm to the outside as the effect that the filter 4 is clogged in case of the preset time or above.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resist coating apparatus and a resist coating method for supplying and coating a resist liquid on a resist coating object in a manufacturing process of semiconductor devices, printed wiring boards, liquid crystal panels and the like.

[0002]

2. Description of the Related Art FIG. 18 is a schematic view showing a structure of a conventional resist coating apparatus for coating a wafer with a photoresist solution in a photolithography process in manufacturing a semiconductor device. The photoresist liquid is contained in the container 1, and one end side of the pipe 9 is inserted into the container 1. The pipe 9 is connected to the suction port of the bellows pump 2, and the resist solution discharged from the bellows pump 2 prevents a filter 4 for removing dust in the resist solution, an opening / closing valve 5 and a dripping. Are supplied onto the wafer 8 via a suck back valve 6 for

The bellows pump 2 is driven by an air cylinder (not shown) to expand and contract, and air is supplied to the air cylinder via a solenoid valve 70. Further, the opening / closing valve 5 and suck back valve 6 are also driven by the air supplied via the electromagnetic valve 70. Conventionally, there are the following methods for setting the supply amount of the resist liquid to the wafer 8.

As shown in FIGS. 19 (a) and 19 (b), the first method is to attach a contact plate 71a to the end of the bellows pump 2 on the air cylinder 3 side, and to move the contact plate 71a forward in the moving direction. A stopper 71 is provided. As a result, when the bellows pump 2 contracts, the contact plate 71a moves to the stopper 71.
And the bellows pump 2 is prevented from contracting. By adjusting the position of the stopper 71, the supply amount of the resist liquid is determined.

The second method, as shown in FIGS. 20 (a) and 20 (b), is, for example, optical sensors 72a, 72 at two positions separated from each other along the expansion / contraction direction of the bellows pump 2.
b is provided, and the detection plate 73 provided at the end of the bellows pump 2 is detected by the sensors 72a and 72b to control the stroke of the bellows pump 2. As a result, the bellows pump 2 is displaced between the sensors 72a and 72b, and a constant resist liquid is supplied.

In the third method, as shown in FIGS. 21 (a) and 21 (b), the relationship between the resist discharge amount and the operation time of the bellows pump 2 is obtained in advance, and the time for supplying air to the cylinder 3 is determined. There is also one that controls t to control the resist solution supply amount.

[0007]

However, FIG.
In the method shown in (1), the operator needs to adjust the position of the stopper 71 according to each wafer or each wafer type when changing the supply amount of the resist solution, which is very complicated and the workability is poor. It is also possible to set the position of the stopper 71 according to the wafer type that requires the most resist liquid and not change the position of the stopper 71 even if the wafer type changes. Then, a large amount of resist solution is wasted, and the running cost is significantly increased.

Also in the method shown in FIG. 20, it is necessary to adjust the positions of the sensors 72a and 72b to change the resist supply amount, similarly to the method shown in FIG. 19, and there are the same drawbacks as the method shown in FIG. . In the method shown in FIG. 21, the resist solution supply amount can be changed by controlling the time for supplying air to the cylinder 3, so that the resist supply amount can be changed very easily. However, if the filter is clogged, the resist supply amount can be changed. In some cases, unevenness may cause unevenness in coating, resulting in defects.

An object of the present invention is to provide a resist coating apparatus and a resist coating method which can easily change the resist supply amount and can avoid the generation of defective products due to clogging of a filter.

[0010]

Means for Solving the Problems The above-mentioned problems include a resist pump for reciprocating a drive shaft in one direction to suck and discharge the resist liquid, and a filter for filtering the resist liquid discharged from the resist pump. Pump driving means for driving the resist pump, resist pump displacement detecting means for detecting displacement of the resist pump in the moving direction of the drive shaft, and resist pump displacement amount detected by the resist pump displacement detecting means are preset. A control unit that drives the resist pump through the pump driving unit until the set displacement amount reaches the set displacement amount, and the time until the displacement amount of the resist pump reaches the set displacement amount is detected and the time is preset. Filter clogging detection means for outputting a filter clogging detection signal when the set time is exceeded Be solved by a resist coating apparatus characterized.

Further, the above-mentioned problem is in the resist coating method of supplying the resist liquid discharged from the resist pump whose drive shaft reciprocates in one direction to the resist coating object through a filter and coating the resist coating object. The resist pump is displaced until the displacement amount with respect to the moving direction of the drive shaft reaches a preset displacement amount to control the supply amount of the resist liquid, and the time until the displacement amount is reached is measured. A resist coating method is characterized in that a filter clogging detection signal is output when the measurement time exceeds a preset set time.

According to the present invention, the displacement of the resist pump in the drive axis direction is detected by the resist pump displacement detection means, and the resist pump is driven by the control means so that the displacement amount of the resist pump becomes a preset displacement amount. Control means. As a result, the resist supply amount can be changed only by changing the set displacement amount, and the resist supply amount can be changed very easily. Further, in the present invention, the time until the displacement of the resist pump reaches the set displacement amount is detected, and this time is compared with a preset time. When the filter is clogged, it takes a long time to reach the set displacement amount, and therefore the filter can be detected based on the comparison result.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. (First Embodiment) FIG. 1 is a schematic view showing a resist coating apparatus according to the first embodiment of the present invention.

Reference numeral 1 is a container containing a resist solution, 2 is a bellows pump, and 3 is an air cylinder for driving the bellows pump 2. A pipe 9 is inserted into the container 1, and the pipe 9 is connected to the suction port of the bellows pump 2. A position detecting plate 7a is attached to the end of the bellows pump 2 on the air cylinder 3 side. A laser displacement sensor 7 is arranged on the side of the air cylinder 2. The laser displacement sensor 7 outputs laser light and outputs an analog signal according to the amount of laser light reflected by the detection plate 7a. Therefore, the displacement amount of the bellows pump 2 can be detected by the laser displacement sensor 7. The displacement amount of the bellows pump 2 detected by the laser displacement sensor 7 is given to the control device 10 described later as bellows displacement information Xs.

The resist solution discharged from the discharge port of the bellows pump 2 is supplied onto the wafer 8 through the filter 4, the opening / closing valve 5 and the suck back valve 6. The filter 4 is for removing dust in the resist solution. The opening / closing valve 5 is for controlling the supply / stop of the resist solution, and the suck back valve 6 is for preventing the resist solution from dripping.

These air cylinder 3 and open / close valve 5
The suck back valve 6 and the suck back valve 6 are both driven by air supplied through a bellows drive electromagnetic valve 15 in a control unit 10 described later. The open / close valve 5 and suck back valve 6 are connected to the air pipe 10a, and the air cylinder 3 is connected to the air pipes 10a and 10b. Also, reference numerals 3a, 3b, 5a and 6
Reference numerals a and 6b are air circuit components including a check valve and a speed control valve, which are provided in the air cylinder 3, the opening / closing valve 5 and the suck back valve 6, respectively.

The control unit 10 includes an initial data storage unit 1
1, control unit 12, clogging determination unit 13, operation stop comparison unit 1
4 and a bellows drive solenoid valve 15.
The initial data storage unit 11 stores, in advance, data indicating the relationship between the bellows displacement amount and the resist discharge amount regarding the bellows pump 2 in the initial state (the filter is new), and the relationship between the bellows displacement and the bellows pump operating time. Is stored.

The control unit 12 stores recipe data of the resist ejection amount according to each wafer or each wafer type. For example, the recipe data includes (1) recipe A set discharge amount 3 cc (2) recipe B set discharge amount 5 cc (3) recipe C set discharge amount 2 cc. The resist discharge amount is set for each recipe. The data is displayed, for example, on a display (not shown). Then, the control unit 12, based on the recipe selected by the operator from the recipe data and the data input from the initial data storage unit 11, the bellows displacement set value Xr, the displacement arrival time set value ts, and the clogging detection set value. It outputs tp and controls the entire system.

The operation stop comparing section 14 detects the bellows displacement set value Xr output from the control section 12 and the laser displacement sensor 7.
Is compared with the bellows displacement information Xs output from the device. When Xs <Xr, the output t0 is set to "H", and Xs≥
When it is Xr, the output t0 is set to "L". The bellows drive solenoid valve 15 supplies air to the air pipe 10b when the output signal t0 of the operation stop comparing unit 14 is "H",
When it is "L", it operates to supply air to the air pipe 10a.

The clogging determination unit 13 inputs the displacement arrival time set value ts and the clogging detection set value tp from the control unit 12, and sets the displacement arrival time set value ts and the output t0 of the operation stop comparison unit 14 to "H". Time difference td = ts-t0 is calculated, and the result is compared with the clogging detection set value tp,
When td ≧ tp, an alarm signal Alarm is output to the outside.

FIG. 2 is a diagram showing an example of the relationship between the bellows displacement amount X and the resist discharge amount M measured in the initial state. As shown in FIG. 2, the bellows displacement amount X and the resist discharge amount M are in a substantially proportional relationship. The initial data storage unit 11 stores a numerical representation of this relationship.
Even if the filter 4 is clogged, if the displacement amount of the bellows pump 2 is constant, the resist discharge amount is also constant. Therefore, the resist discharge amount can be controlled by controlling the bellows displacement amount.

In FIG. 3, the filter 4 is in a new state (solid line).
FIG. 6 is a diagram showing an example of the relationship between the operating time of the air cylinder and the displacement amount of the bellows pump measured in a clogged state (broken line). As shown in FIG. 3, when the filter 4 is clogged, the load on the bellows pump 2 is increased, and the bellows pump displacement amount is constant (for example, 5 m in FIG. 5).
It takes longer to reach m). The relationship between the bellows pump displacement and time in this initial state is also quantified,
It is stored in the initial data storage unit 11.

The operation of the resist coating apparatus having the above structure will be described below. Note that it is assumed that the initial data storage unit 11 has previously stored data as shown in FIGS. In the initial state, the bellows drive solenoid valve 15 supplies air to the air pipe 10a, the drive shaft of the air cylinder 3 is at the most retracted position, and the opening / closing valve 5 is closed.

First, when the operator selects a desired recipe from the recipe data according to the type of the wafer 8 to which the resist solution is to be applied, the control unit 12 causes the initial data storage unit 1 to operate.
By referring to the data stored in No. 1, the displacement set value Xr, the displacement arrival time set value ts, and the clogging detection set value tp according to the selected recipe are obtained. Then, the control unit 12
Outputs the displacement setting value Xr to the operation stop comparing unit 14, and outputs the displacement arrival time setting value ts and the clogging detection setting value tp to the clogging detection unit 13.

The operation stop comparing section 14 compares the displacement set value Xr input from the control section 12 with the bellows displacement information Xs input from the laser displacement sensor 7, and initially Xr> Xs.
Therefore, "H" is output as the output t0. The bellows drive solenoid valve 15 stops the air supply to the air pipe 10a by this "H" signal,
Start supplying air to b. As a result, the opening / closing valve 5 is opened, the air cylinder 3 is actuated, and the bellows pump 2 is displaced in the contracting direction, and the resist solution is discharged from the bellows pump 2. This resist solution is supplied to the wafer 8 via the filter 4, the opening / closing valve 5 and the suck back valve 6.

At this time, the detection plate 7a is the bellows pump 2
The displacement of the bellows pump 2 is detected by the laser displacement sensor 7, and the laser displacement sensor 7 outputs the bellows displacement information Xs. The bellows displacement information Xs increases as the bellows pump 2 contracts, and eventually the bellows displacement information Xs becomes equal to the displacement set value Xr. When the bellows displacement information Xs is Xs ≧ Xr, the operation stop comparing unit 14 sets the output t0 to “L” because the predetermined amount of resist liquid is supplied to the wafer 8.

The bellows drive solenoid valve 15 operates when the output t0 of the operation stop comparing section 14 becomes "L".
The air supply to b is stopped and the air is supplied to the air pipe 10a. As a result, the drive shaft 3c of the air cylinder 3 moves in the opposite direction, the bellows pump 2 starts to expand, and the resist liquid is sucked into the bellows pump 2 from the container 1. Further, air is supplied to the opening / closing valve 5 to close the opening / closing valve 5, and air is also supplied to the suck back valve 6 to prevent dripping. The bellows pump 2 extends until the drive shaft 3c of the air cylinder 3 reaches the most retracted position.

On the other hand, the clogging judging section 13 monitors the output t0 of the operation stop comparing section 14 and measures th when the time t0 is "H". Then, the displacement arrival time set value ts
And the time difference td = ts−th between th and th are calculated, and the time difference td is compared with the clogging detection set value tp. Then, the time difference td is equal to or larger than the clogging detection set value tp (td ≧
In the case of tp), the alarm signal Alarm is output to the outside,
Notify the clogging of the filter 4 to the outside. The alarm signal Alarm may be output to the outside, for example, when td ≧ tp three or more times in ten consecutive cycles.

In the present embodiment, the displacement of the bellows pump 2 (that is, the amount of resist solution discharged) is detected by the laser displacement sensor 7 and the air cylinder 3 is drive-controlled based on the detection result, so that the filter 4 is operated. Regardless of clogging, a constant amount of resist solution can be constantly supplied to the wafer 8. Further, the amount of resist supply can be changed only by selecting a desired one from the recipe data of the control unit 12, so that it is extremely easy. Further, there is also an advantage that clogging of the filter 4 can be detected and maintenance becomes easy.

(Second Embodiment) FIG. 4 shows a second embodiment of the present invention.
3 is a circuit diagram showing a control unit of the resist coating apparatus according to the embodiment of FIG. Note that this embodiment is the same as the first embodiment except that the configuration of the control unit is different, and will be described with reference to FIG. In the present embodiment, the control unit 10 is composed of a microcomputer. That is, the control unit 1
Reference numeral 0 denotes a CPU (central processing unit) 28, a memory 27, an A / D (analog / digital) converter 21, a D / A (digital / analog) converter 22, a timer 23 and an I which are connected via an internal bus 26. It is composed of an / O (input / output) interface 29, a comparator 24, a 2-input AND gate 25, a relay 30, and a bellows drive solenoid valve 31.

The bellows displacement information Xs output from the laser displacement sensor 7 is input to the non-inverting input terminal (+) of the comparator 24, converted into a digital signal by the A / D converter 21, and passed through the internal bus 26. C
PU28. In the memory 27, as initial data, data showing the relationship between the bellows displacement amount and the resist discharge amount as shown in FIG. 2, data showing the relationship between the time and the bellows displacement amount as shown in FIG. 3, recipe data and the like. Remembered The CPU 28 reads the bellows displacement set value Xr, the displacement arrival time set value ts, and the clogging detection set value tp from the memory 27 according to the recipe data selected by the operator, and sets the displacement set value Xr to D / A.
The value is output to the converter 22 and the value (ts + tp) obtained by adding ts and tp is output to the timer 23.

The D / A converter 22 converts the displacement set value Xr given via the internal bus 26 into an analog signal. The displacement set value Xr of the analog signal is input to the inverting input terminal (−) of the comparator 24. On the other hand, the timer 23 is supplied via the internal bus 26 (ts + t
p) as the timer set value. Further, a start signal is applied to the timer 23 from the CPU 28.

The output ta of the timer 23 is input to one input terminal of the 2-input AND gate 25. Also, AND
The output signal c of the comparator 24 is input to the other input terminal of the gate 25. And this AND gate 25
The output signal e of is supplied to the CPU 28 via the internal bus 26. I / O interface 29
Outputs a signal for controlling the bellows drive electromagnetic valve 31 based on a signal given from the CPU 28 via the internal bus 26. A contact of a relay 30 is connected between the I / O interface 29 and the bellows drive solenoid valve 31. The relay 30 is driven by the output signal c of the comparator 24.

FIG. 5 is a timing chart showing the operation of the above control unit. The CPU 28 first outputs the displacement set value Xr read from the memory 27 to the D / A converter 22 according to the recipe data selected by the operator. The D / A converter 22 converts the displacement set value Xr into an analog signal, and the comparator 2
4 is output.

After that, the CPU 28 outputs a start signal to the timer 23, and at the same time, the I / O interface 2
The bellows drive signal is output to 9. When the start signal is input, the timer 23 sets the output signal ta to “H” for ts + tp time. In addition, the I / O interface 29 operates the bellows drive electromagnetic valve 31 in response to the bellows drive signal sent from the CPU 28 to supply air to the air pipe 10b.

As a result, the air cylinder 3 operates and the bellows pump 2 contracts, and the resist solution is supplied to the wafer 8. At this time, as the bellows pump 2 contracts, the bellows displacement information Xs increases. The output signal c of the comparator 24 is “L” when the bellows displacement information Xs is smaller than the displacement set value Xr, but becomes “H” when the bellows displacement information Xs is equal to or larger than the displacement set value Xr. When the output c of the comparator 24 becomes "H", the relay 30 operates, the contact 31a is opened, the bellows drive electromagnetic valve 31 operates, and the air supply to the air pipe 10b is stopped, and the air pipe 10a is stopped. The supply of air to the

By the way, when the filter 4 is not clogged (normal), a pulse is generated at the output e of the AND gate 25 as shown in FIG. But filter 4
Is clogged, the output signal of the comparator 24 does not become "H" within the time (ts + tp), and the AND gate 25
The output e of the signal remains "L". CPU 28 is AND
When no pulse is generated from the gate 25 within the time (ts + tp), it is determined that the filter 4 is clogged and I
Alarm signal Al via the O / O interface 29
Output arm.

Also in the present embodiment, the same effect as that of the first embodiment can be obtained. (Third Embodiment) FIG. 6 is a block diagram showing a control unit of a resist coating apparatus according to a third embodiment of the present invention. Note that the present embodiment is also the same as the first embodiment except that the configuration of the control unit is different, and therefore will be described with reference to FIG.

Also in the present embodiment, the CPU 28, the memory 27, the I / O interface 29, etc. are connected via the internal bus 26 as in the second embodiment.
Bellows displacement information X output from the laser displacement sensor 7
s is A / D converted by the A / D converter 21, and is transmitted to the CPU 28 via the internal bus 26. A timer 33 is connected to the internal bus 26. This timer 33 includes the internal bus 26 from the CPU 28.
The start / stop signal is input via the timer 33, and the timer 33 measures the time tm from the input of the start signal to the input of the stop signal, and sends the result to the CPU 28 via the internal bus 26. It has become.

Further, a bellows drive solenoid valve 31 is connected to the I / O interface 29. The operation of this embodiment will be described below with reference to the flowchart shown in FIG. It should be noted that the memory 27 stores in advance the data shown in FIGS. 2 and 3 as initial data, and based on the recipe selected by the operator, Xr and (t
s + tp) is output.

First, in steps 101 and 102, the CPU
28 sends a signal of "H" to the bellows drive solenoid valve 31 via the I / O interface 29, and sends a start signal to the timer 33. As a result, the bellows drive solenoid valve 31 supplies air to the air pipe 10b, the air cylinder 3 operates, the bellows pump 2 discharges the resist solution, and the wafer 8 is coated with the resist solution.

On the other hand, the CPU 28 inputs the bellows displacement information Xs sent from the laser displacement sensor 7 through the A / D converter 21 in step 103, and in step 104, the bellows displacement information Xs and the bellows displacement set value. Compare with Xr. And step 10
When Xs is smaller than Xr in 4 (when NO)
Returns to step 103. X in step 104
When s is greater than or equal to Xr (when YES), a predetermined amount of resist liquid has been discharged from the bellows pump 2, so the routine proceeds to step 105, where the signal to the bellows drive solenoid valve 31 is set to "L" and In step 106, a stop signal is output to the timer 33. As a result, the bellows drive solenoid valve 31 stops the supply of air to the air pipe 10b and supplies the air to the air pipe 10a.
Then, the air cylinder 3 operates in the direction of extending the bellows pump 2 to suck the resist solution from the container 1 into the bellows pump 2, and the on-off valve 5 is closed to stop the supply of the resist solution. Furthermore, the suck back valve 6 prevents dripping.

After sending a stop signal to the timer 33 in step 106, the CPU 28 inputs the counting time tm from the timer 33. Then, in step 107, this time tm is stored in the memory 27 (t
s + tp), and when tm is (ts + tp) or less (when NO), the process proceeds to step 108, it is determined that the filter 4 is not clogged, and the operation for one cycle is ended. On the other hand, in step 107, tm is (ts + tp)
In the above case (when YES), the routine proceeds to step 109, where it is judged that the filter 4 is in the clogged state, and the I / O
The alarm signal Alarm is output via the interface 29.

Also in this embodiment, the same effect as that of the first embodiment can be obtained. (Fourth Embodiment) FIG. 8 is a view showing a bellows pump displacement detecting portion of a resist coating apparatus according to a fourth embodiment of the present invention. FIG. 8 (a) shows a state in which the bellows pump 2 is extended. 8 (b) shows a state in which the bellows pump 2 is contracted. In addition, in the present embodiment, the configuration other than the bellows displacement detection unit is basically the same as that of the first embodiment, and therefore will be described with reference to FIG.

In this embodiment, the linear potentiometer 41 is provided near the end of the bellows pump 2 on the cylinder side.
Is arranged. In this potentiometer 41, fixed terminals at both ends are connected to a power source Vcc and ground, respectively, and a movable terminal moves together with the cylinder side end of the bellows pump 2. Then, the voltage of the movable terminal is sent to the control unit 10 as bellows displacement information Xs.

As described above, the potentiometer 41 can be used as the bellows pump displacement amount detecting portion. (Fifth Embodiment) FIG. 9 is a view showing a bellows pump displacement detecting portion of a resist coating apparatus according to a fifth embodiment of the present invention, and FIG. 9 (a) shows a state in which the bellows pump 2 is extended. 9 (b) shows a state in which the bellows pump 2 is contracted. Note that, also in the present embodiment, the configuration other than the bellows displacement detection unit is basically the same as that of the first embodiment, and therefore will be described with reference to FIG.

In the present embodiment, a capacitive displacement sensor 42 is arranged laterally of the air cylinder 2, and a detection plate 42a is provided at the cylinder side end of the bellows pump 2.
Is installed. Since the distance between the capacitive displacement sensor 42 and the detection plate 42a changes due to the expansion and contraction of the bellows pump 2, the capacitance between the capacitive displacement sensor 42 and the detection plate 42a changes. The output of the sensor 42 changes according to the change in the capacitance, and the output of the sensor 42 is sent to the control unit 10 as Xs.

As described above, the displacement sensor 42 can be used as the bellows pump displacement amount detector. (Sixth Embodiment) FIG. 10 is a view showing a bellows pump displacement amount detecting portion of a resist coating apparatus according to a sixth embodiment of the present invention, and FIG. 10 (a) shows the bellows pump 2 extended. A state, FIG.10 (b) shows the state where the bellows pump 2 contracted. Note that, also in the present embodiment, the configuration other than the bellows displacement amount detection unit is basically the same as that of the first embodiment, and therefore will be described with reference to FIG.

In the present embodiment, the reflection type infrared sensor 43 is arranged on the side of the air cylinder 3,
Further, the detection plate 43 is provided at the cylinder side end of the bellows pump 2.
a is attached. The expansion and contraction of the bellows pump 2 changes the distance between the infrared sensor 43 and the detection plate 43a, which changes the amount of reflected light. The output of the sensor 43 changes with the change of the reflected light amount, and the output of the sensor 43 is sent to the control unit 10 as bellows displacement information Xs.

As described above, the infrared sensor 43 can be used as the bellows pump displacement amount detecting portion. (Seventh Embodiment) FIG. 11 is a diagram showing a bellows displacement amount detecting portion of a resist coating apparatus according to a seventh embodiment of the present invention. Note that, also in the present embodiment, the configuration other than the bellows displacement amount detection unit is basically the same as that of the first embodiment, and therefore will be described with reference to FIG.

In the present embodiment, the linear encoder 44 is arranged on the side of the air cylinder 3 with its longitudinal direction aligned with the expansion / contraction direction of the bellows 2. The movable portion of the linear encoder 44 moves together with the cylinder side end of the bellows pump 2. The linear encoder 44 outputs two-phase signals VA and VB as the movable part moves.

FIG. 12 (a) is a diagram showing a signal processing circuit for the signal output from the linear encoder 44, and FIG. 12 (b).
Similarly, FIG. 13 is a circuit diagram showing the digital circuit 45 in detail, and FIG. 13 is a timing chart showing the operation of the signal processing circuit. The signal VA output from the linear encoder 44,
VB is input to the digital circuit 45, and the pulse signal and the direction signal are output from the digital circuit 45. As shown in FIG. 12B, the digital circuit 45 includes Schmitt trigger type inverters 51, 52, 54, a resistor 53, a capacitor 55, exclusive OR circuits 56, 57, and a flip-flop circuit 58.

Among the two-phase signals, VA is input to one input terminal of each of the exclusive OR circuits 56 and 57 via the inverter 51, and the inverter 54 via the delay circuit composed of the resistor 53 and the capacitor 55.
Is input to The output of the inverter 54 is input to the other input terminal of the exclusive OR circuit 56, and the exclusive OR circuit 56 outputs a pulse signal (CLOC).
K) is output.

Of the two-phase signals, VB is the inverter 52.
Is input to the other input terminal of the exclusive OR circuit 57 via. The flip-flop circuit 58 inputs the pulse signal (CLOCK) and the output of the exclusive OR circuit 57 and outputs a direction signal. That is, it is understood that when the direction signal output from the digital circuit 45 is "L", the bellows is displaced in the expanding direction, and when it is "H", the bellows is displaced in the contracting direction.

The up / down counter 46 integrates the pulse signal when the direction signal is "H", and subtracts the pulse signal when the direction signal is "L". And D /
The A converter 27 uses the up / down counter 46.
The output of is converted into D / A and output as bellows displacement information Xs. By using the linear encoder 44 and the signal processing circuit, the displacement amount of the bellows can be detected with high accuracy. Also in this embodiment, the same effect as that of the first embodiment can be obtained.

(Eighth Embodiment) FIG. 14 is a block diagram showing a control unit of a resist coating apparatus according to an eighth embodiment of the present invention. The present embodiment is the same as the first embodiment except that the configurations of the bellows displacement amount detection unit and the control unit are different, and therefore will be described with reference to FIG.

In this embodiment, a linear encoder 44 is used as the bellows displacement amount measuring unit, and the output of the linear encoder 44 is processed by the digital circuit 45. This digital circuit 45 is the same as the digital circuit 45 shown in FIG.
The pulse signal and the direction signal output from the above are input to the up / down counter 46. The output of the up / down counter 46 is input to the internal bus 26 of the control unit 10. The configuration and operation of the control unit 10 are the same as those of the control unit shown in FIG. 6 except that the bellows displacement information Xs is given to the control unit 10 as a digital signal, and thus detailed description thereof will be omitted.

In the present embodiment, since the linear encoder 44 is used as the bellows displacement amount detecting section, the displacement amount of the bellows pump can be detected with high accuracy and the output of the up / down counter 46 can be directly fed to the internal bus. 26, there is an advantage that the configuration of the control unit 10 is simpler than that of the third embodiment. (Ninth Embodiment) FIG. 15 is a block diagram showing a control unit of a resist coating apparatus according to a ninth embodiment of the present invention. This embodiment is the same as the eighth embodiment except that the configuration of the control unit is different. Therefore, in FIG. 15, the same parts as those in FIG. 14 are denoted by the same reference numerals, and detailed description thereof will be omitted. .

In the present embodiment, as in the eighth embodiment, the output of the linear encoder 44 is processed by the digital circuit 45 and the up / down counter 46,
The bellows displacement information Xs is input to the control unit 10. The output of the up / down counter 46 is input to the comparator (digital comparator) 61. On the other hand, this comparator 61
The CPU 28 inputs the bellows displacement set value Xr. When the bellows displacement information Xs matches the bellows displacement set value Xr, the comparator 61 outputs a match signal to the internal bus 26.
To the CPU 28 via.

In this embodiment, since the comparator 61 compares the bellows displacement information Xs with the bellows displacement set value Xr, the CPU 28 is different from the eighth embodiment.
This has the advantage of reducing the load on the. (Tenth Embodiment) FIG. 16 shows a resist coating apparatus according to the tenth embodiment of the present invention. The present embodiment is different from the first embodiment in that the bellows pump 2 is driven by a motor, and other configurations are basically the same as those in the first embodiment.
6, the same components as those in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

In the present embodiment, when the motor 18 rotates in the normal direction, the rotational movement of the motor shaft is converted into the axial reciprocating movement of the drive shaft 18c in the gear box 18a, and the drive shaft 18c causes the bellows pump 2 to move. It is designed to be expanded and contracted. In this case, as the motor 18, a motor whose rotation speed decreases due to an increase in load due to clogging of the filter 4 is used, or a clutch mechanism or the like is provided in the gear box 18a and the bellows pump is clogged due to clogging of the filter 4. The displacement speed of 2 is changed.

Further, the solenoid valve 16 provided in the control unit 10 turns on the air pipe 10a when the signal t0 output from the operation stop comparing section 14 is "H", as in the first embodiment. Air is supplied to the on-off valve 5 and suck back valve 6 via the air supply, and the supply is stopped when the air is "L". Further, the bellows drive motor driver 17 outputs a signal for rotating the motor 7 in the forward direction when the output t0 of the operation stop comparing section 14 is "H", and rotating it in the reverse direction when the output t0 is "L".

Also in this embodiment, the same effect as that of the first embodiment can be obtained. As shown in FIG. 17, the rotary encoder 18b is attached to the motor 18, and the two-phase signals VA and VB output from the rotary encoder 18b are controlled via the signal processing circuit shown in FIG. 12, FIG. 14 or FIG. You may make it input into a unit.

[0064]

As described above, according to the present invention, the displacement of the registration pump in the drive axis direction is detected by the registration pump displacement detection means so that the displacement amount of the registration pump becomes a preset displacement amount. In addition, since the control means controls the resist pump driving means, the resist supply amount can be changed only by changing the set displacement amount.

Further, in the present invention, the clogging of the filter is detected by detecting the time until the displacement amount of the resist pump reaches the set displacement amount and comparing the time with a preset time. To do. This has the advantage that the maintainability of the resist coating apparatus is improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a resist coating apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an example of a relationship between a bellows displacement amount X and a resist discharge amount M in an initial state.

FIG. 3 is a diagram showing an example of a relationship between an operating time of an air cylinder and a displacement amount of a bellows pump in an initial state and a state in which a filter is clogged.

FIG. 4 is a circuit diagram showing a control unit of a resist coating apparatus according to a second embodiment of the present invention.

FIG. 5 is a timing chart showing the operation of the control unit of the resist coating apparatus according to the second embodiment of the present invention.

FIG. 6 is a block diagram showing a control unit of a resist coating apparatus according to a third embodiment of the present invention.

FIG. 7 is a flowchart showing an operation of a control unit of the resist coating apparatus according to the third embodiment of the present invention.

FIG. 8 is a diagram showing a bellows pump displacement detection unit of a resist coating apparatus according to a fourth embodiment of the present invention.

FIG. 9 is a diagram showing a bellows pump displacement detection unit of a resist coating apparatus according to a fifth embodiment of the present invention.

FIG. 10 is a diagram showing a bellows pump displacement amount detection unit of a resist coating apparatus according to a sixth embodiment of the present invention.

FIG. 11 is a diagram showing a bellows displacement amount detection unit of a resist coating apparatus according to a seventh embodiment of the present invention.

FIG. 12 is a diagram showing a signal processing circuit for a signal output from a linear encoder of a resist coating apparatus according to a seventh embodiment of the present invention.

FIG. 13 is a timing chart showing the operation of the signal processing circuit for the signal output from the linear encoder of the resist coating apparatus according to the seventh embodiment of the present invention.

FIG. 14 is a block diagram showing a control unit of a resist coating apparatus according to an eighth embodiment of the present invention.

FIG. 15 is a block diagram showing a control unit of a resist coating apparatus according to a ninth embodiment of the present invention.

FIG. 16 is a diagram showing a resist coating apparatus according to a tenth embodiment of the present invention.

FIG. 17 is a diagram showing an example in which a rotary encoder is attached to the motor of the resist coating apparatus according to the tenth embodiment of the present invention.

FIG. 18 is a schematic view showing a configuration of a conventional resist coating apparatus that coats a wafer with a photoresist in a photolithography process at the time of manufacturing a semiconductor device.

FIG. 19 is a diagram showing an example of a method of setting a resist solution supply amount in a conventional resist coating apparatus.

FIG. 20 is a diagram showing another example of a method of setting a resist solution supply amount in a conventional resist coating apparatus.

FIG. 21 is a diagram showing still another example of the method of setting the resist solution supply amount in the conventional resist coating apparatus.

[Explanation of symbols]

 1 Container 2 Bellows Pump 3 Air Cylinder 4 Filter 5 Opening / Closing Valve 6 Suck Back Valve 7 Laser Displacement Sensor 8 Wafer 9 Pipe 10 Control Unit 11 Initial Data Storage 12 Control Section 13 Clogging Judgment Section 14 Operation Stop Comparison Section 15, 31 Bellows Drive solenoid valve 18 Motor 18a Gear box 18b Rotary encoder 21 A / D converter 22 D / A converter 23, 33 Timer 24 Comparator 26 Internal bus 27 Memory 28 CPU 29 I / O interface 41 Potentiometer 42 Capacitive displacement sensor 43 Infrared sensor 44 Linear encoder 45 Digital circuit 46 Up / down counter

Claims (5)

[Claims] 1. A resist pump that sucks and discharges a resist solution by reciprocating a drive shaft in one direction, a filter that filters the resist solution discharged from the resist pump, and a pump driving unit that drives the resist pump. A resist pump displacement detecting means for detecting displacement of the resist pump in the moving direction of the drive shaft, and the resist pump displacement detecting means until the resist pump displacement amount detected by the resist pump displacement detecting means reaches a preset set displacement amount. Control means for driving the resist pump via pump driving means, and detecting a time until the displacement amount of the resist pump reaches the set displacement amount, and when the time is equal to or longer than a preset set time, a filter And a filter clogging detecting means for outputting a clogging detection signal. 2. The set time is set based on a measurement result obtained by measuring a time until the displacement amount of the resist pump reaches the set displacement amount in an initial state. Item 1. The resist coating apparatus according to Item 1. 3. The set displacement amount in an initial state is
The resist coating apparatus according to claim 1, wherein a relationship between a displacement amount of the resist pump and a discharge amount of the resist liquid is measured, and the relationship is set based on the measurement result. 4. The resist coating apparatus according to claim 1, wherein the resist pump is a bellows pump driven by an air cylinder or a motor. 5. A resist coating method for supplying a resist solution discharged from a resist pump in which a drive shaft reciprocates in one direction to a resist coating object through a filter to apply the resist liquid, wherein a moving direction of the drive shaft of the resist pump. While controlling the supply amount of the resist liquid by displacing the resist pump until the displacement amount with respect to the preset displacement amount is set, the time until the preset displacement amount is measured is measured in advance. A resist coating method, wherein a filter clogging detection signal is output when the set time has been exceeded.