JPH10247614A - Treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lessen the affection to the preciseness of detection of pump pressure, etc., and to detect the clogging of a filter by a pressure gauge. SOLUTION: In this treatment apparatus in which a pump 1, which feeds a treatment solution by pressure, a filter 3 and a flow rate control valve 4 are provided on a treatment solution feeding pipeline in the above-mentioned order, and a pressure gauge 2 is provided between the pump 1 and the filter 3. The degree of clogging of the filter 3 is detected form the amount of decrease of the pressure gauge 2 immediately after the finish of pressure feeding. Also, a plurality of filters 3 are connected in parallel through a pipeline switching circuit with which a filter can be selected. A clogged filter 3 is separated from the treatment solution feeding pipeline 8, and a flow passage is changed to the other filter 3. As a result, a filter can be changed without stopping the device, and the throughput of the device can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing apparatus for supplying a processing liquid such as a resist to an object to be processed such as a semiconductor wafer and performing processing such as resist coating.

2. Description of the Related Art In an apparatus for supplying a processing liquid to a processing target and processing the same, for example, a resist coating apparatus for a semiconductor wafer, a filter is interposed in a processing liquid supply pipe in order to remove foreign matter in the processing liquid. However, the filter is easily clogged during use, and it is likely to cause an accident that a processed object afterwards becomes a defective product. Therefore, it is necessary to detect clogging of the filter and replace the filter. Therefore, filter clogging is reliably and easily detected,
Further, there is a demand for a processing apparatus capable of shortening the operation stop time of the processing apparatus for replacing the filter.

[0003]

2. Description of the Related Art In a conventional processing apparatus, the pressure of a processing liquid before and after a filter is measured, and clogging of the filter is detected from the pressure difference. Hereinafter, a conventional processing apparatus will be described using a resist coating apparatus as an example.

FIG. 7 is a configuration diagram of a conventional processing apparatus, and shows a main configuration of a resist coating apparatus. Referring to FIG. 7, a wafer to be processed 7 is horizontally mounted on a rotating table 11 driven to rotate about a vertical axis by a rotating mechanism 12. A discharge port 6 is provided directly above the object 7 to be processed.
A resist, which is a processing liquid 9 intermittently discharged from the discharge port 6, is supplied onto the rotating processing target 7 and applied. In order to prevent the resist from leaking after the discharge, the discharge port 6
A suckback 5 is provided nearby.

The processing liquid 9 stored in the processing liquid storage container 13 passes through the processing liquid supply line 8 connecting the processing liquid storage container 13 and the discharge port 6 and is interposed in the processing liquid supply line 8. Pumped by the pump 1, transported to the discharge port 6, and supplied onto the workpiece. Further, a flow control valve 4 is provided between the pump 1 and the discharge port. Normally, pump 1 and flow control valve 4
The flow control valve 4 is opened during the discharge period in which the pump 1 operates, and the flow control valve 4 is closed during the pump 1 stop period.

The filter 3 comprises a pump 1 and a flow control valve 4
The processing liquid supply pipe 8 is provided between the two. Further, two pressure gauges 2 a and 2 b for measuring the processing liquid pressure in the processing liquid supply pipe 8 are provided at the entrance and exit of the filter 3. The outputs of the two pressure gauges 2a and 2b are compared by the differential pressure detector 10a, and the differential pressure between the inlet and the outlet of the filter 3 is obtained.

FIG. 8 is a diagram showing a change in the pressure in the processing liquid supply pipe line, and shows the processing liquid pressure indicated by a pressure gauge provided at the entrance and exit of the filter 3 before and after the discharge period.
Referring to FIG. 8, while the pumping control signal indicated by C in the drawing is in the discharge period 24 (represented as a period of H level in the drawing), the pump 1 is operated and the flow control valve 4 is opened. Since the processing liquid 9 flows through the filter 3, the pressure indicated by the pressure gauge 2a on the inlet side of the filter 3 (shown by a in the figure) and the pressure indicated by the pressure gauge 2b on the outlet side of the filter 3 (b shown in the figure) ), A pressure difference P having a magnitude corresponding to the degree of clogging of the filter 3 is generated. The conventional processing apparatus detects the clogging of the filter 3 by measuring the differential pressure during the discharge period 24.

However, since the two pressure gauges 2a and 2b are used, it is necessary to ensure the adjustment of the two pressure gauges, which is troublesome. This is because if this adjustment is insufficient, a precise differential pressure cannot be measured. In addition, the installation cost of the pressure gauge is increased by two and the cost is increased.

In order to solve such a drawback, a method has been devised for detecting clogging of a filter using a single pressure gauge. In this method, one pressure gauge measures the pressure in the pump or the pressure at the inlet of the filter during the discharge period, and the measured pressure exceeds the pre-measured and stored pressure when the filter becomes clogged. Clogging is detected. Therefore, clogging can be detected with one pressure gauge. However, the pressure inside the pump or at the filter inlet fluctuates depending on the operating speed of the pump. For this reason, every time the pump is adjusted, the pressure when the filter is clogged must be measured and stored again, which requires a great deal of time and labor.

Further, in the above-mentioned conventional processing apparatus, the processing apparatus must be stopped in order to replace the clogged filter, which causes a decrease in the throughput of the processing apparatus.

[0011]

As described above, in the conventional processing apparatus, the pressure at the inlet and the outlet of the filter during the discharge period is measured using two pressure gauges, and the filter is clogged from the pressure difference. However, there is a problem that it takes time and effort to adjust between the two pressure gauges, and the apparatus becomes expensive.

In the method of detecting clogging of the filter by measuring the pressure in the pump or the inlet of the filter with a single pressure gauge, the pressure in the clogged state must be measured again each time the pump is adjusted. There is a problem that it requires a lot of labor and time.

Further, in the conventional processing apparatus, the processing apparatus must be stopped to replace the clogged filter, which causes a problem that the throughput of the processing apparatus is reduced.

According to the present invention, filter clogging is detected using a single pressure gauge which does not require re-measurement at the time of pump adjustment by detecting filter clogging from the amount of change in pressure at the filter inlet immediately after the end of the discharge period. It is an object of the present invention to provide a processing device for detecting a filter, and further to provide a processing device in which a device stoppage period during filter replacement is reduced.

[0015]

FIG. 1 is a block diagram of a first embodiment of the present invention, and FIG. 5 is a block diagram of a second embodiment of the present invention. Is represented.

In order to solve the above-mentioned problems, a first configuration of the present invention, as shown in FIG. 1, comprises a discharge port 6 for supplying a processing liquid 9 to an object to be processed 7 and a processing liquid storage container Discharge port 6
A processing liquid supply pipe 8 for transporting the processing liquid 9 to the processing liquid, and a pump interposed in the processing liquid supply pipe 8 for pressure-feeding the processing liquid 9 toward the discharge port 6 of the processing liquid supply pipe 8. 1 and the pump 1
A filter 3 provided between the filter 3 and the discharge port 6, and a flow rate provided between the filter 3 and the discharge port 6. In a processing apparatus having a control valve 4, a pressure of the processing liquid 9 in the processing liquid supply pipe 8 is provided in the processing liquid supply pipe 8 between the pump 1 and the filter 3. In response to the pressure gauge 2 and the signal 21b for terminating the pressure of the processing liquid 9, the stop signal 22b for stopping the pump 1 and the closing signal 23b for closing the flow control valve 4 are sent to the pump 1 and the flow control valve, respectively. 4 and the output of the pressure gauge 2 are observed, and when the amount of decrease in the pressure, which occurs immediately after the reception of the pumping end signal 21b, exceeds a preset pressure, the filter 3 is used. Pressure measuring unit 10 for generating a clogging alarm 20 The second configuration is characterized in that, in the processing device of the first configuration, the filters 3a and 3b arbitrarily selected from the plurality of filters 3 connected in parallel are provided with the filters 3a and 3b. A line switching circuit 16 for switching the flow path of the processing liquid 9 is provided.
In response to this, the pipeline switching circuit 16 is switched.

The inventor of the present invention has found a phenomenon that the pressure in the processing liquid supply pipe at the filter inlet decreases immediately after the discharge period of the processing liquid, and the amount of the decrease corresponds to the degree of clogging of the filter. Make sure you do. Note that this pressure drop occurs for a short time after the discharge period elapses, for example, within 0.2 to 0.8 seconds after the end of the discharge period, and when there is no clogging of the filter, several seconds after the end of the discharge period. Subsequent gradual pressure drops are clearly distinguished. The present invention has been devised based on this fact.

In the first configuration of the present invention, referring to FIG. 1, a pump 1, a pressure gauge 2, a filter 3 and a pump 3 are connected to a processing liquid supply pipe 8 connecting the processing liquid storage container 13 and the discharge port 6. The flow control valves 4 are provided in this order. Further, the controller 15 having received the pressure feed end signal 21b notifying the end of the discharge period sends the stop signal 22b to the pump 1
, The pump 1 is stopped, the flow control valve 4 is closed, and the discharge operation of the processing liquid 9 is terminated.
The pumping end signal 21b may be generated inside the controller 15, or may be transmitted from an external control device.

On the other hand, the pressure sending end signal 21b is
Also transmitted to 0. The pressure measuring unit 10 observes the output of the pressure gauge 2 and measures a pressure drop that occurs within a predetermined period immediately after receiving the pumping end signal 21b. This predetermined period is long enough that the pressure drop due to the filter clogging described above can be sufficiently observed, and can be distinguished from a gradual pressure drop that lasts several seconds from the end of the discharge period when the filter is not clogged. Must be as short as possible. Usually, this predetermined period can be determined experimentally and depends on the discharge mechanism or the processing liquid, but is, for example, about 0.2 to 1 second in a resist coating apparatus.

Further, the pressure measuring unit 10 recognizes that clogging of the filter 3 has been detected when the amount of pressure drop immediately after receiving the pressure-feeding end signal 21b exceeds a predetermined pressure, and issues a clogging alarm. Generate 20. On the basis of the clogging alarm 20, necessary operations, for example, replacement of a filter and conveyance of an object to be processed are performed. Here, the preset pressure given in advance is a pressure that decreases immediately after the discharge period, which is observed when the filter 3 is clogged to a necessary degree, and can be experimentally obtained.

In this configuration, in order to detect clogging of the filter, it is sufficient to observe a short-term pressure change after the elapse of the discharge period. Therefore, even if the pressure during the discharge period fluctuates due to adjustment of the pump, the pressure change is normalized by the absolute value of the pressure, and the normalized pressure change is compared with the set pressure to accurately determine the degree of filter clogging. Can be evaluated. Therefore, there is no need to measure the absolute value of the pressure, and no precise adjustment of the pressure gauge is required. Furthermore, even if the pressure fluctuates, the standardized set pressure does not change much.
After the initial set pressure is determined, it is not necessary to experimentally determine the set pressure again each time the pump is adjusted. Further, in this configuration, it is sufficient to install one pressure gauge, and adjustment between a plurality of pressure gauges is not required, and the processing apparatus can be manufactured at low cost.

In the second configuration of the present invention, referring to FIG. 5, a plurality of filters 3a and 3b are connected in parallel via a switching circuit 16. The switching circuit 16 sends out the processing liquid 9 to one filter 3a selected from the plurality of filters 3a and 3b. And clogging alarm 2
When 0 is received, the switching circuit is switched to send the processing liquid 9 to another filter 3b that has not been used.

In this configuration, when the filter is clogged, the filter is automatically switched to another filter, so that there is no need to stop the processing device. Further, the clogged filter is separated from the processing liquid supply pipe to which the processing liquid is being fed under pressure by the switching circuit, so that the filter can be replaced while the processing apparatus is operating.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The first embodiment of the present invention relates to a processing apparatus using a semiconductor wafer as an object to be processed and a resist as a processing liquid, that is, a resist coating apparatus.

Referring to FIG. 1, a wafer serving as an object to be processed 7 is placed horizontally on a turntable 11 driven to rotate about a vertical axis by a rotation mechanism 12. The discharge port 6 is provided directly above the workpiece 7, and the suck back 5 is provided near the discharge port 6. The processing liquid storage container 13 and the discharge port 6 are connected by a processing liquid supply pipe 8, and the processing liquid 9 in the processing liquid storage container 13 is discharged to the discharge port 6 by the pump 1 provided in the processing liquid supply pipe 8. Pumped. The pressure inside the processing liquid storage container 13 is maintained at a constant pressure through a gas supply pipe 14. A flow control valve 4 is provided between the pump 1 and the discharge port. The above configuration is the same as the above-described conventional example.

FIG. 4 is a conceptual view of a pump according to the first embodiment of the present invention, showing a pump used in the processing apparatus according to the first and second embodiments of the present invention. Referring to FIG. 4, pump 1 is mainly configured by bellows 26 and air actuator 27. The bellows 26 is expanded and contracted by a piston 27a of an air actuator 27,
Is sucked from the inlet 26a and is pressure-fed from the outlet 26b. The inlet 26a and the outlet 26b are connected to the processing liquid supply pipe 8. The air actuator 27 is operated by air supplied from an air inlet through a valve controlled by a control signal 27c transmitted from the controller 15.

Referring to FIG. 1, the filter 3 is provided between the pump 1 and the flow control valve 4. A pressure gauge 2 is provided for measuring the pressure between the filter 3 and the pump 1, that is, the pressure in the processing liquid supply pipe 8 on the inlet side of the filter 3. The pressure measurement unit 10 compares the pressure in the processing liquid supply pipe 8 indicated by the pressure gauge 2 with a preset pressure stored in the pressure measurement unit 10 in advance.

The controller 15 mainly includes an electronic circuit for controlling the sequence of the entire processing apparatus, and includes a microprocessor, a storage device, an input / output circuit, and peripheral circuits necessary for controlling equipment such as the pump 1. . The controller 15 generates a pressure feed control signal 21 for defining a processing liquid discharge period according to a sequence program therein. The pumping control signal 21 is composed of a signal indicating a discharge period, for example, a high-level electric signal that continues during the discharge period, and a period other than the discharge period, a signal indicating a discharge stop period of the processing liquid, for example, a low-level electric signal. The transition from the signal indicating the ejection stop period to the signal indicating the ejection period is configured as a pumping start signal 21a, and the transition from the signal indicating the ejection period to the signal indicating the ejection stop period is configured as the pumping end signal 21b. Each part of the processing device is controlled by the controller 15 based on these signals.

Hereinafter, the operation of the resist coating apparatus according to the first embodiment will be described. Referring to FIG. 1, first, after confirming that the object 7 is placed on the turntable 11,
The controller generates a pumping start signal 21a, and uses the pumping start signal 21a as a trigger to generate an activation signal 22a and an opening signal 23a. Note that the pumping control signal 21 after the pumping start signal 21a is generated indicates the ejection period. The operation signal 22a is transmitted to the pump 1 as the pump control signal 22, and the pump 1 receiving this starts the pumping operation. The release signal 23a is transmitted to the flow control valve 4 as the valve control signal 23, and the flow control valve 4 which has received the signal opens the processing liquid supply pipe 8. As a result, the processing liquid 9 is pressure-fed in the processing liquid supply pipe 8 and is supplied onto the processing target 7 from the discharge port.

When the ejection period has elapsed since the generation of the pumping start signal 21a, the pumping control signal 21 shifts to a signal indicating the ejection stop period, and the pumping end signal 21b is generated. The controller 15 generates the closing signal 23b and the stop signal 22b by using the pumping end signal 21b as a trigger, and transmits the closing signal 23b and the stop signal 22b to the pump 1 as the valve control signal 23 and the pump control signal as the pump control signal, respectively. Upon receiving the closing signal 23b, the flow control valve 4 closes the processing liquid supply pipe 8 and stops the supply of the processing liquid 9 to the processing target 7. Upon receiving the stop signal 22b, the pump 1 stops, and the pumping of the processing liquid 9 stops. Further, the controller 15 sends the pressure sending end signal 21b to the pressure measuring unit 1
The pressure measurement unit 10 transmits the value to 0, and starts measuring the pressure drop after the end of the ejection period. Next, the operation of the pressure measuring unit 10 will be described.

FIG. 6 is a graph showing pressure fluctuations in the first embodiment of the present invention, and shows fluctuations in the pressure in the processing liquid supply line on the filter inlet side before and after the discharge period, which is observed by a pressure gauge. I have. FIG. 6A shows the pressure fluctuation when the filter 3 is not clogged, and FIG. 6C shows the pressure fluctuation when the filter 3 is clogged to the extent that the filter 3 needs to be replaced. 6B shows the pressure fluctuation when the degree of clogging of the filter 3 is intermediate between FIGS. 6A and 6B.

Referring to FIG. 6, the pressure measuring unit 10 changes the display of the discharge period 24 of the pressure feed control signal 21 from the discharge stop period 25
Receiving a change to the display as a pumping end signal 21b, pumping end signal 21b received at t regular time intervals the pressure gauge 2 outputs between ₁ and t ₂ when the advance length has passed the measurement period determined Start sampling. This measurement period t
₁ length t ₂ -t ₁ of ~t _2, for example 0.2 seconds to 1.0
Seconds. Referring to FIG. 6 (a), since the pressure drop not caused by the filter clogging usually requires several seconds to several tens of seconds, the pressure drop ΔP occurring during such a short measurement period.
Is extremely small and can usually be ignored. On the other hand, the pressure drop when the filter is clogged almost ends within this measurement period with reference to FIGS. 6 (b) and 6 (c).
Therefore, by setting the measurement period to this extent, it is possible to separately measure only the pressure drop caused by the filter clogging.

The measurement of the pressure drop is performed during the measurement period t _{1 to} t ₂
Is determined as the difference between the maximum and minimum values of the pressure measured within. In order to obtain this difference, a method generally used as a method for obtaining the amount of pressure fluctuation can be applied. For example, the maximum value of the pressure is obtained by storing the first sampling value of the pressure started by the pumping end signal 21b, sequentially comparing the stored value with the subsequent sampling value, and replacing the stored value with a larger value. Further, the minimum value of the pressure is obtained by storing the first sampling value in another storage device and replacing the stored value with a smaller value.

After the end of the measurement period, the difference between the maximum value of the pressure and the minimum value of the pressure is normalized by the maximum value of the pressure, and the pressure drop amount [Δ
P] is obtained, and when this [ΔP] exceeds a preset pressure stored in advance, it is determined that clogging has been detected.
Outputs 0. The set pressure is obtained by experimentally obtaining the amount of pressure drop when the filter is in a clogged state in which the filter needs to be replaced, and uses a value normalized as described above.

The controller receiving the clogging alarm is shown in FIG.
, The operation of the rotation mechanism 12 is stopped, and the object 7 is accommodated in a predetermined position. At the same time, the alarm lamp is turned on to notify the operator that the filter 3 needs to be replaced. After that, the sequence is stopped and the apparatus enters a standby state. Normally, the controller is restarted after the filter 3 is replaced, and the subsequent processing is continued.

FIG. 2 is a wafer transfer diagram of the first embodiment of the present invention, and FIG. 3 is a wafer transfer diagram of another wafer of the first embodiment of the present invention. The wafer storage position and the orientation of the stored wafer are shown in a plan view. This is shown in the figure. Referring to FIG. 2, the wafer as the object to be processed 7 is accommodated in a cassette and mounted on the setting section 31. Next, one object to be processed 7 is conveyed onto the turntable 11 of the application unit 32, and after the resist (the processing liquid 9) is supplied to the upper surface, when no clogging alarm is output, spin coating is performed. Next, the processed object 7a that has been normally processed without outputting the clogging alarm is dried in the drying unit 33 and further stored in the cassette of the storage unit 34. When the clogging alarm is output after the resist (processing liquid 9) is supplied to the upper surface, the spin coating is stopped, and the processing target 7b when the clogging warning is output is an abnormally processed target. 7b (shown by a broken line in FIGS. 2 and 3) is stored in the abnormal-time storage section 35. In the processing apparatus shown in FIG. 3, the storage unit 35 of the apparatus shown in FIG.
4 accommodates the processed object 7a and the abnormally processed object 7b that have been processed normally. At this time, since the abnormally processed object 7b is accommodated by being rotated by 180 degrees, the position of the orientation facet of the abnormally processed object 7b accommodated in the accommodating portion 34 is different from that of the normally treated object 7a. On the contrary, both can be easily identified.

In the second embodiment of the present invention, the filter 3
The configuration is the same as that of the first embodiment except for. Referring to FIG. 5, in this embodiment, two filters 3a and 3b are provided in parallel. A pipeline switching circuit 16 is inserted into the entrance of each of the filters 3a and 3b, and the processing liquid is pumped only to one of the filters 3a selected by the pipeline switching circuit 16. The other filter 3 b is separated from the processing liquid supply pipe 8. Therefore, the clogging alarm 20
Is not output, the processing liquid 9 is filtered by the one filter 3a.

The line switching circuit 16 includes a clogging alarm 20.
Received, the processing solution flow path to one of the filters 3a, which has clogged, is shut off, and
The processing liquid flow path is switched to b. At this time, the treatment of the object to be processed abnormally is performed in the same manner as in the first embodiment.
Thereafter, the controller is automatically restarted, and the next object following the abnormally processed object is processed normally.
Since the clogged filter 3a is separated from the processing liquid supply line 8, it can be replaced with a new one while the processing apparatus is operating. Therefore, in this embodiment, it is not necessary to stop the processing device for replacing the filter, and the throughput can be increased.

[0039]

As described above, according to the present invention, the clogging of the filter is detected by measuring the pressure drop immediately after the elapse of the treatment liquid discharge period. It is possible to detect clogging of the filter without being affected by fluctuations, and to provide a processing device with high detection accuracy and low cost. Further, since it is not necessary to stop the operation of the apparatus when clogging occurs and when replacing the filter, it is possible to provide a processing apparatus having a high throughput.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a first embodiment of the present invention.

FIG. 2 is a wafer transfer diagram of the first embodiment of the present invention.

FIG. 3 is another wafer transfer diagram of the first embodiment of the present invention.

FIG. 4 is a conceptual diagram of a pump according to a first embodiment of the present invention.

FIG. 5 is a configuration diagram of a second embodiment of the present invention.

FIG. 6 is a diagram showing pressure fluctuations in the first embodiment of the present invention.

FIG. 7 is a conceptual diagram of a conventional processing apparatus.

FIG. 8 is a diagram showing a change in pressure in a processing liquid supply pipe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pump 2, 2a, 2b Pressure gauge 3, 3a, 3b Filter 4 Flow control valve 5 Suck back 6 Discharge port 7, 7, a, 7b Workpiece 8 Processing liquid supply line 9 Processing liquid 10 Pressure measuring unit 10a Differential pressure detection Apparatus 11 Turntable 12 Rotary mechanism 13 Processing liquid storage container 14 Gas supply pipe 15 Controller 16 Pipeline switching circuit 20 Clogging alarm 21 Pumping control signal 21a Pumping start signal 21b Pumping ending signal 22 Pump control signal 22a Operating signal 22b Stop signal 23 Valve control signal 23a Open signal 23b Close signal 24 Discharge period 25 Discharge stop period 26 Bellows 27 Air actuator 31 Setting part 32 Coating part 33 Drying part 34 Storage part 35 Abnormal storage part

Claims (2)

[Claims] A discharge port for supplying a processing liquid to an object to be processed;
A processing liquid supply pipe for transporting the processing liquid from the processing liquid storage container to the discharge port, and a pressure supply of the processing liquid toward the discharge port of the processing liquid supply pipe interposed between the processing liquid supply pipe and the processing liquid supply pipe. Pump, a filter provided in the processing liquid supply pipe between the pump and the discharge port, and a flow rate provided in the processing liquid supply pipe between the filter and the discharge port. A processing device provided with a control valve, a pressure gauge provided in the processing liquid supply pipe between the pump and the filter, for measuring a pressure of the processing liquid in the processing liquid supply pipe; In response to the processing solution pressure stop signal, the controller sends a stop signal for stopping the pump and a closing signal for closing the flow control valve to the pump and the flow control valve, respectively, and observes the output of the pressure gauge. Therefore, the amount of the pressure drop that occurs immediately after the reception of the pumping end signal is determined in advance. Processing apparatus characterized by comprising a pressure measurement unit for generating a clogging alarm filter when exceeding a constant has been set pressure. 2. The processing apparatus according to claim 1, wherein a line switching circuit for switching a flow path of the processing liquid is provided to one of the plurality of filters connected in parallel, which is arbitrarily selected. Preparing, receiving the clogging alarm,
A processing device for switching the pipeline switching circuit.