JP6159651B2 - Filter cleaning method, liquid processing apparatus, and storage medium - Google Patents

Description

  The present invention cleans a filter provided in a circulation line in a tank for storing the treatment liquid and a liquid treatment apparatus in which the treatment liquid is supplied to the liquid treatment unit via a circulation line that exits from the tank and returns to the tank. Regarding technology.

  The manufacturing process of a semiconductor device includes a liquid processing process in which a processing liquid such as a chemical liquid is supplied to a substrate such as a semiconductor wafer to perform a liquid processing such as an etching process and a cleaning process on the substrate. Such a liquid processing step is executed by a liquid processing apparatus including a large number of liquid processing units.

  In such a liquid processing apparatus, the processing liquid is supplied from a processing liquid supply mechanism common to the respective liquid processing units. The processing liquid supply mechanism has a tank and a circulation line that exits from the tank and returns to the tank. A plurality of branch lines are connected in parallel to the circulation line, and the processing liquid is supplied from each branch line to the corresponding liquid processing unit. The circulation line is provided with a filter in order to prevent contaminants such as particles from being supplied to the liquid processing unit (see, for example, Patent Document 1).

  The filter is changed regularly. After the new filter is installed, a flushing liquid (pure water or a chemical solution for co-washing) is supplied to the tank, and then a pump provided in the circulation line is driven to circulate the flushing liquid in the circulation line. By continuing the circulation, particles contained in the flushing liquid flowing through the circulation line are trapped by the filter, and the particle level of the flushing liquid gradually decreases. When the particle level falls below the reference value, the process proceeds to the next step (co-washing or chemical treatment).

  During the above circulation, the particle level did not easily fall below the reference value, and it took time to move to the next process. As a result of analyzing the cause, it was found that particles were contained in a new filter, and these particles flowed out to the circulation line when circulating the flushing liquid, and contaminated the circulation line and the tank. However, a method for completely eliminating particles contained in a new filter has not yet been established.

JP 2006-080547 A

  The present invention provides a technique for cleaning a filter in a state in which the filter is mounted at a predetermined position in the circulation line while minimizing the diffusion of contaminants that may be present inside the filter into the circulation system.

  In a preferred embodiment, the present invention includes a tank for storing processing liquid, a circulation line connected to the tank, and a pump for forming a flow of processing liquid from the tank and returning to the tank in the circulation line. In a liquid processing apparatus comprising: a filter interposed in the circulation line; and a processing unit that performs liquid processing on a substrate using a processing liquid flowing in the circulation line, in the filter cleaning method for cleaning the filter, A flushing liquid filling step of filling the inside of the filter with the flushing liquid by supplying the flushing liquid to only a part of the circulation line and the tank while the filter is installed at a predetermined position of the circulation line; , By discharging the flushing liquid supplied to the part of the circulation line and the tank from the drain line, A flushing liquid discharge step of the serial filter pull the flushing liquid, to provide a filter cleaning method comprising a.

  In another preferred embodiment, the present invention forms a tank for storing a processing liquid, a circulation line connected to the tank, and a flow of the processing liquid that leaves the tank and returns to the tank in the circulation line. A liquid processing apparatus comprising: a pump; a filter interposed in the circulation line; and a processing unit that performs liquid processing on a substrate using a processing liquid flowing in the circulation line, and the operation of the liquid processing apparatus The control device further includes a control device for supplying flushing liquid to only a part of the circulation line and the tank with the filter installed at a predetermined position of the circulation line. A flushing liquid filling step for filling the inside of the filter with the flushing liquid; and the flushing liquid supplied to the part of the circulation line and the tank. A storage unit for storing a program for carrying out a filter cleaning method comprising: a flushing liquid discharging step of discharging the flushing liquid from the filter by discharging from the drain line connected to the part of the tank or the tank A liquid processing apparatus is provided, wherein the filter cleaning method is performed by the control device executing the program.

  In still another preferred embodiment, the present invention provides a tank for storing a processing liquid, a circulation line connected to the tank, and a flow of the processing liquid that leaves the tank and returns to the tank in the circulation line. And a processing unit that performs liquid processing on a substrate using processing liquid flowing in the circulation line, and a processing unit that performs liquid processing on the substrate. A storage medium storing a computer program is provided.

  According to the present invention, when supplying the flushing liquid for cleaning to the filter, the flushing liquid is supplied only to a part of the circulation line, so that it is possible to limit the diffusion range of contaminants existing inside the filter. . For this reason, the contaminant level can be reduced to an allowable range in a short time after the filter replacement.

The circuit diagram which shows roughly the whole structure of a liquid processing apparatus. The effect | action figure which shows replacement | exchange of a filter and a washing | cleaning procedure. The circuit diagram for demonstrating the washing | cleaning of the filter in another embodiment.

  Embodiments of the invention will be described below with reference to the accompanying drawings.

  As shown in FIG. 1, the liquid processing apparatus includes a plurality of processing units (liquid processing units) 16 that perform liquid processing on a substrate, and a processing fluid supply source 70 that supplies the processing liquid to the processing units 16. Yes.

  The processing fluid supply source 70 includes a tank 102 that stores the processing liquid, and a circulation line 104 that exits from the tank 102 and returns to the tank 102. The circulation line 104 is provided with a pump 106. The pump 106 creates a circulating flow that exits the tank 102, passes through the circulation line 104, and returns to the tank 102. A filter 108 for removing contaminants such as particles contained in the processing liquid is provided in the circulation line 104 on the downstream side of the pump 106. If necessary, auxiliary equipment (such as a heater) may be further provided in the circulation line 104.

  One or more branch lines 112 are connected to the connection area 110 set in the circulation line 104. Each branch line 112 supplies the processing liquid flowing through the circulation line 104 to the corresponding processing unit 16. Each branch line 112 can be provided with a flow rate adjusting mechanism such as a flow rate control valve, a filter, or the like, if necessary.

The liquid processing apparatus includes a tank liquid replenishing unit 116 that replenishes the tank 102 with a processing liquid or a processing liquid constituent component. The tank 102 is provided with a drain line 118 for discarding the processing liquid in the tank 102.

  As shown in FIG. 2, the liquid processing apparatus includes a control device 4. The control device 4 is a computer, for example, and includes a control unit 18 and a storage unit 19. The storage unit 19 stores a program for controlling various processes executed in the liquid processing apparatus. The control unit 18 controls the operation of the liquid processing apparatus by reading and executing the program stored in the storage unit 19.

  Such a program may be recorded on a computer-readable storage medium, and may be installed in the storage unit 19 of the control device 4 from the storage medium. Examples of the computer-readable storage medium include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnetic optical disk (MO), and a memory card.

  Next, filter replacement and cleaning procedures will be described with reference to FIG. The following cleaning procedure can be automatically performed under the control of the control device 4 in which a program configured to execute the procedure is installed. Alternatively, the following cleaning procedure can be executed by the operator manually operating the liquid processing apparatus.

  In the example shown in FIG. 2, a heater 109 is interposed between the pump 106 and the filter 108 in addition to the configuration shown in FIG. 1. In FIG. 2, the height relationship between the components of the liquid processing apparatus is shown. In many liquid processing apparatuses, the height relationship among the tank 102, the pump 106, and the filter 108 is actually as shown in FIG. The height of the top of the inside of the filter 108 (specifically, the height of the highest position of the internal space of the filter 108 that is filled with liquid during actual use) is lower than the normal maximum liquid level of the tank 102. “Normal maximum liquid level” means the highest liquid level allowed during normal operation of the liquid processing apparatus, and is lower than the liquid level when the internal space of the tank 102 is completely filled with liquid without any gaps. The liquid level shown in FIGS. 2 (d) and 2 (g).

  In the illustrated liquid processing apparatus, since the tank liquid replenishment unit 116 has a function of supplying first and second flushing liquids described later, the tank liquid replenishment unit 116 is used as the flushing liquid supply unit. A dedicated flushing liquid supply unit (separate from the tank liquid replenishment unit 116) for supplying the flushing liquid may be provided in 102.

  First, a filter (not shown) that has been used for a predetermined time is removed, and a new filter 108 is installed in the circulation line 104 as shown in FIG. At this time, the filter 108 is installed in the circulation line 104 in the same state as when the liquid processing apparatus is actually operated. That is, not only the filter 108 is connected to the circulation line 104, but also the air vent ports 108a and 108b and the drain ports 108c and 108d are provided with corresponding air vent lines and drain lines (both shown in FIG. (Not shown).

[First flushing liquid filling step]
Next, as shown in FIG. 2B, the on-off valve 117 (not shown in FIG. 1) is closed with the on-off valve 119 (not shown in FIG. 1) provided in the drain line 118 closed. ) And the pure water (DIW) as the first flushing liquid is supplied into the tank 102 from the tank liquid replenishment section 116 to a predetermined liquid level higher than the height of the top inside the filter 108 (in the case of the illustrated example, “ The liquid level may be lower than the “normal maximum liquid level”. In this way, the water level of the flushing liquid in the tank 102 and the water level of the flushing liquid in the filter 108 are balanced, so that the internal space of the filter 108 is completely filled with the flushing liquid. At this time, it is not necessary to move the pump 106. At this time, the circulation line 104 is filled with the flushing liquid to a position corresponding to the same height as the liquid level of the flushing liquid in the tank 102.

[First flushing liquid discharge step]
Next, as shown in FIG. 2C, the on-off valve 119 of the drain line 118 is opened. Then, all the flushing liquid shown in FIG. 2B is discharged from the drain line 118 from the drain line 118 connected to the bottom wall of the tank 102. At this time, the flushing liquid filling the filter 108 flows out to the circulation line 104, flows into the tank 102 through the heater 109 and the pump 106 in this order, and flows out from the drain line 118. The particles existing in the filter 108 flow out of the drain line 118 along with the flow of the flushing liquid.

  The flushing liquid filling process and the flushing liquid discharge process are alternately performed a plurality of times, for example, 10 times. As a result, most of the particles originally present in the filter 108 flow out to the drain line 118. Some of the particles originally present in the filter 108 are inside the filter 108 or the inner wall surface of the pipe forming the circulation line 104, the inner wall surface of the flow path inside the pump 106 and the heater 109, and the inner wall surface of the tank 102. May remain slightly, but the amount is very small.

[First flushing liquid circulation step]
After the final flushing liquid discharge step is completed, the on-off valve 119 of the drain line 118 is closed, and the on-off valve 117 is opened to open the tank 102 from the tank liquid replenishment unit 116 (see FIG. 1), as shown in FIG. Pure water as a flushing liquid is injected into the pump, and the pump 106 is operated to circulate the flushing liquid in the circulation line 104. At this time, the liquid level of the flushing liquid in the tank 102 is set to, for example, the normal highest liquid level described above. After circulating the flushing liquid for a predetermined time, the pump 106 is stopped and the on-off valve 119 of the drain line 118 is opened. As a result, almost all of the flushing liquid in the tank 102, the circulation line 104, and various devices such as the pump 106 and the heater 109 provided in the circulation line 104 flows out from the drain line 118. As a result, particles remaining in the circulation system including the tank 102 and the circulation line 104 are reduced. In the first flushing liquid circulation step, it is preferable to energize the heater 109 to raise the temperature of the flushing liquid.

[Second flushing liquid filling step]
Next, as shown in FIG. 2 (e), with the on-off valve 119 of the drain line 118 closed, the on-off valve 117 is opened and the tank liquid replenishment unit 116 enters the tank 102 as a second flushing liquid. A liquid (a processing liquid to be used for processing a substrate, for example, a chemical liquid) is injected to a predetermined liquid level higher than the height of the filter 108. At this time, the pump does not need to be moved. Thereby, the internal space of the filter 108 is completely filled with the flushing liquid. Further, the circulation line 104 is filled up to a position having the same height as the liquid level of the flushing liquid in the tank 102. The second flushing liquid filling step is the same as the first flushing liquid filling step except for the type of liquid to be supplied.

[Second flushing liquid discharge process]
Next, as shown in FIG. 2 (f), an unillustrated on-off valve provided in the drain line 118 is opened. Then, all the flushing liquid shown in FIG. 2 (e) is discharged from the drain line 118 connected to the bottom wall of the tank. At this time, the flushing liquid that has filled the filter 108 flows out into the circulation line 104, flows into the tank 102 sequentially through the heater 109 and the pump 106, and flows out into the drain line 118. The second flushing liquid discharge step is the same as the first flushing liquid discharge step except for the type of liquid to be discharged.

  The second flushing liquid filling process and the second flushing liquid discharge process are processes for replacing the pure water as the first flushing liquid existing in the circulation system including the tank 102 and the circulation line 104 with the treatment liquid. The second flushing liquid filling process and the second flushing liquid discharge process may be performed at least once each. Thus, a series of procedures accompanying the filter replacement is completed.

  Thereafter, an unillustrated on-off valve provided in the drain line 118 is closed, and as shown in FIG. 2G, the processing liquid (the same liquid as the second flushing liquid) is injected into the tank 102 from the tank liquid replenishing unit 116. At the same time, the pump 106 is operated to circulate the flushing liquid in the circulation line 104. At this time, the liquid level of the flushing liquid in the tank 102 is set to, for example, the normal highest liquid level described above. After this state is continued for a predetermined time, the number of particles in the processing liquid is checked by a particle counter or the like. If there is no problem, the processing liquid is supplied to the processing unit 16 via the branch line 112 to process the substrate. be able to.

  According to the above embodiment, even if particles are present in the new filter 108, the particles in the treatment liquid can be suppressed to a very low level in a short time from the start of circulation of the treatment liquid. Thereby, the stop time of the apparatus accompanying filter replacement can be shortened, and the throughput of the apparatus can be improved.

  In contrast to the above embodiment, if the flushing liquid is circulated through the circulation system including the tank 102 and the circulation line 104 immediately after the replacement of the filter 108, the particles originally in the filter 108 diffuse into the entire circulation system. It will be. The particles once diffused in the entire circulation system can only be captured by the filter 108 by circulating the flushing liquid and passing through the filter 108. The particles do not exist only in the circulating fluid, but adhere / separate from / to the wall surface of the flow path. Therefore, it takes a very long time to reduce the particle level to within an allowable range. In the above-described embodiment, in the first flushing liquid filling process and the first flushing liquid discharge process, the diffusion range of the particles is greatly limited by limiting the area in contact with the flushing liquid in the circulation system. For this reason, the time required for capturing the particles once diffused in the circulation system by the filter 108 can be greatly reduced.

  In the above embodiment, the height of the top portion inside the filter 108 is lower than the normal maximum liquid level of the tank 102. Actually, this is the case with many actual liquid processing apparatuses, but it is also conceivable to set the height of the top inside the filter 108 higher than the normal maximum liquid level of the tank 102 for the convenience of the apparatus layout. . A procedure for cleaning a new filter immediately after replacement in such a case will be described with reference to FIG. FIG. 3 shows the actual height relationship of each component of the liquid processing apparatus (H is high and L is low).

  As shown in FIG. 3, when the filter 108 is located higher than the tank 102, the first flushing liquid filling step and the first flushing liquid discharging step are performed as follows.

  A drain line 120 is connected to the circulation line 104 on the downstream side of the filter 108. The drain line 120 is provided with an on-off valve 122. On the downstream side of the connection point of the drainage line 120, an opening / closing valve 124 is provided in the circulation line 104. It is preferable that an appropriate flow resistance is set in the drainage line 120. For this purpose, an orifice (not shown) is provided in the drainage line 120 on the upstream side of the on-off valve 122, or the drainage line 120 is drained. The flow path cross-sectional area of the liquid line 120 is smaller than the flow path cross-sectional area of the circulation line 104.

  In the first flushing liquid filling step, the tank liquid replenishment unit 116 starts the tank operation with the open / close valve 119 of the drain line 118 closed, the open / close valve 122 of the drain line 120 opened, and the open / close valve 124 of the circulation line 104 closed. An amount of flushing liquid (for example, pure water) that does not cause idling of the pump 106 is injected into the pump 102 and the pump 106 is operated.

  Then, the flushing liquid in the tank 102 flows through the circulation line 104 and flows into the filter 108 and flows out into the drainage line 120. Since an appropriate flow resistance is set in the drainage line 120, the flushing liquid is quickly filled up to the highest position in the internal space of the filter.

  When the entire area of the filter 108 is filled with flushing liquid, the pump 106 is stopped and the on-off valve 119 of the drain line 118 is opened. Thereby, a 1st flushing liquid discharge process is performed. That is, the flushing liquid in the filter 108, the flushing liquid in the circulation line 104, and the flushing liquid in the tank 102 flow out from the drain line 118 (partially from the drain line 120). Along with the flow of the flushing liquid, particles existing in the filter 108 flow out to the drain line 118 (partially the drain line 120).

  Also in the case of using the configuration of FIG. 3, it is preferable to alternately repeat the first flushing liquid filling process and the first flushing liquid discharge process. In the first flushing liquid circulation step, pure water as flushing liquid is injected into the tank 102 from the tank liquid replenishing unit 116 with the on-off valves 119 and 122 closed and the on-off valve 124 opened, and the pump 106 is operated. And the flushing liquid can be circulated in the circulation line 104. The second flushing liquid filling step and the second flushing liquid discharge step are performed in the same procedure as the first flushing liquid filling step and the first flushing liquid discharge step using a processing liquid (for example, a chemical liquid) as the flushing liquid. Can do.

In the embodiment of FIG. 3, compared with the embodiment of FIGS. 1 and 2, the range in which particles diffuse in the first flushing liquid filling step is widened. Nevertheless, a circulation line 104 downstream of the connection point of the drain line 120, the upper region of the tank need not be contaminated by particles. Therefore, as compared with the case where the flushing liquid is circulated through the circulation system including the tank 102 and the circulation line 104 immediately after the replacement of the filter 108, the time required for reducing the particle level within the allowable range can be shortened. Can do.

16 processing units ( processing section )
102 Tank 104 Circulation line 106 Pump 108 Filter 118 Drain line 120 Drain line

Claims (5)

A tank for storing processing liquid; a circulation line connected to the tank; a pump for forming a flow of processing liquid from the tank to the tank and returning to the tank; and a filter interposed in the circulation line In a liquid processing apparatus comprising: a processing unit that performs liquid processing on a substrate using a processing liquid flowing through the circulation line, in the filter cleaning method for cleaning the filter,
A flushing liquid filling step of filling the inside of the filter with the flushing liquid by supplying the flushing liquid to only a part of the circulation line and the tank while the filter is installed at a predetermined position of the circulation line; ,
Flushing for removing the flushing liquid from the filter by discharging the part of the circulation line and the flushing liquid supplied to the tank from the part of the circulation line or a drain line connected to the tank. A liquid discharge process;
With
In the flushing liquid filling step, filling the inside of the filter with the flushing liquid means that the level of the flushing liquid in the tank is higher than the height of the top of the internal space of the filter in a state where the pump is stopped. This is performed by supplying the flushing liquid to the tank until it becomes, and at this time, only a portion of the circulation line having a height below the liquid level of the flushing liquid in the tank is filled with the flushing liquid. , filter cleaning method. The flushing liquid filling step and said flushing liquid discharge step are repeated alternately, the filter washing method according to claim 1, wherein. After performing the flushing liquid filling step and the flushing liquid discharge step at least once, storing the flushing liquid in the tank and operating the pump to circulate the flushing liquid in the circulation line;
Thereafter, stopping the circulation of the flushing liquid and discharging the flushing liquid from the drain line;
Then, a second flushing liquid filling step of filling the inside of the filter with the other flushing liquid by supplying only another flushing liquid to the tank and the tank, and
Thereafter, the separate flushing liquid supplied to the part of the circulation line and the tank is discharged from the filter by discharging the part of the circulation line or the drain line connected to the tank. A second flushing liquid discharging step of removing the flushing liquid of
Further comprising a filter washing method according to claim 1 or 2. A tank for storing the processing liquid;
A circulation line connected to the tank;
A pump that forms a flow of processing liquid that exits the tank and returns to the tank in the circulation line;
A filter interposed in the circulation line;
A processing unit for performing liquid processing on the substrate using the processing liquid flowing through the circulation line;
A liquid processing apparatus comprising:
The liquid processing apparatus further includes a control device that controls the operation of the liquid processing apparatus,
The control device has a storage unit that stores a program for performing the filter cleaning method, and the filter cleaning method is implemented by the control device executing the program,
The filter cleaning method includes:
A flushing liquid filling step of filling the inside of the filter with the flushing liquid by supplying the flushing liquid to only a part of the circulation line and the tank while the filter is installed at a predetermined position of the circulation line; ,
Flushing for removing the flushing liquid from the filter by discharging the part of the circulation line and the flushing liquid supplied to the tank from the part of the circulation line or a drain line connected to the tank. for example Bei a liquid discharge step,
In the flushing liquid filling step, filling the inside of the filter with the flushing liquid means that the level of the flushing liquid in the tank is higher than the height of the top of the internal space of the filter in a state where the pump is stopped. This is performed by supplying the flushing liquid to the tank until it becomes, and at this time, only a portion of the circulation line having a height below the liquid level of the flushing liquid in the tank is filled with the flushing liquid. , liquid processing equipment. A tank for storing processing liquid; a circulation line connected to the tank; a pump for forming a flow of processing liquid from the tank to the tank and returning to the tank; and a filter interposed in the circulation line A storage medium storing a computer program for causing a liquid processing apparatus to perform a filter cleaning method with a processing unit that performs liquid processing on a substrate using processing liquid flowing in the circulation line,
The filter cleaning method comprises:
A flushing liquid filling step of filling the inside of the filter with the flushing liquid by supplying the flushing liquid to only a part of the circulation line and the tank while the filter is installed at a predetermined position of the circulation line; ,
Flushing for removing the flushing liquid from the filter by discharging the part of the circulation line and the flushing liquid supplied to the tank from the part of the circulation line or a drain line connected to the tank. A liquid discharge process,
In the flushing liquid filling step, filling the inside of the filter with the flushing liquid means that the level of the flushing liquid in the tank is higher than the height of the top of the internal space of the filter in a state where the pump is stopped. This is performed by supplying the flushing liquid to the tank until it becomes, and at this time, only a portion of the circulation line having a height below the liquid level of the flushing liquid in the tank is filled with the flushing liquid. It characterized the this, the storage medium.

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