JP7724125B2 - Processing liquid supply device and processing liquid supply method - Google Patents

Description

This disclosure relates to a treatment liquid supply device and a treatment liquid supply method.

Patent Document 1 discloses a resist liquid supply device equipped with a processing liquid container that stores resist liquid, a nozzle that dispenses resist liquid onto a wafer, and a resist liquid supply path consisting of piping that connects the processing liquid container and the nozzle. The resist liquid supply path is equipped with a buffer tank that temporarily stores resist liquid from the processing liquid container, a filter that filters the resist liquid to remove foreign matter, a pump, a flow rate adjuster, an operation valve, and a suck-back valve, in this order from upstream. Resist liquid is dispensed by opening the air-operated valve and operating the pump, which moves the resist liquid in the buffer tank from the processing liquid container downstream through the resist liquid supply path. Therefore, the resist liquid is dispensed from the nozzle at a flow rate set by the flow rate adjuster, for example.

Japanese Patent Application Laid-Open No. 2016-139665

The technology disclosed herein improves the cleanliness of the processing liquid supplied to the processing liquid discharge section onto the substrate while reducing the consumption of the processing liquid.

One aspect of the present disclosure is a processing liquid supply device that supplies a processing liquid to a discharge portion that discharges the processing liquid onto a substrate, the processing liquid supply device including: a supply pipe connected to the discharge portion; a first pump that is interposed in the supply pipe and simultaneously sucks and discharges the processing liquid so as to discharge the processing liquid at a constant flow rate and a constant pressure , and pressure-feeds the processing liquid to the discharge portion; a first on-off valve that is interposed in the supply pipe upstream of the first pump; a filter that is interposed in the supply pipe and filters the processing liquid; and a second on-off valve that is interposed in the supply pipe downstream of the first pump. the treatment system comprises an on-off valve, a return line having one end branched off from a position in the supply line between the first pump and the filter and the second on-off valve and the other end connected to the supply line downstream of the first on-off valve and upstream of the first pump and the filter, a second pump interposed in the return line and pressure-feeding the treatment liquid toward the one end of the return line, a third on-off valve interposed in the return line between the one end and the second pump, and a fourth on-off valve interposed in the return line between the other end and the second pump.

According to the present disclosure, it is possible to improve the cleanliness of the processing liquid supplied to the processing liquid discharge section for the substrate while reducing the consumption of the processing liquid.

1 is an explanatory diagram illustrating an outline of the configuration of a processing liquid supply device according to an embodiment of the present invention; 10A and 10B are diagrams illustrating a state of the treatment liquid supply device during a circulating discharge operation. 10A and 10B are diagrams illustrating a state of the treatment liquid supply device during a discharge operation. FIG. 10 is a diagram showing a state of the processing liquid supply device during a refilling operation.

In the photolithography process used in the manufacturing of semiconductor devices, etc., a series of processes are performed to form a predetermined resist pattern on a substrate such as a semiconductor wafer (hereinafter referred to as "wafer"). This series of processes includes, for example, a resist coating process in which a resist solution is supplied onto the substrate to form a resist film, an exposure process in which the resist film is exposed to light, and a development process in which a developer is supplied to the exposed resist film and developed.

Processing liquids such as resist liquid and developer liquid are discharged onto the substrate through a discharge nozzle. The supply pipe connected to the discharge nozzle is also fitted with a filter to remove minute foreign objects (particles) from the processing liquid.

However, even if a filter is provided as described above, if the processing liquid remains in the supply pipeline, foreign matter may be included in the processing liquid discharged onto the substrate, which may be detected as a defect.
To avoid this, there is a method of periodically discharging the processing liquid in the supply pipeline from a discharge nozzle, etc., but this method consumes a large amount of processing liquid due to the amount of discharge, and there is room for improvement in terms of cost.

The technology disclosed herein improves the cleanliness of the processing liquid while reducing the consumption of the processing liquid supplied to the processing liquid discharge section for the substrate.

The treatment liquid supply device and treatment liquid supply method according to this embodiment will be described below with reference to the drawings. Note that in this specification and drawings, elements having substantially the same functional configuration will be assigned the same reference numerals, and redundant description will be omitted.

FIG. 1 is an explanatory diagram showing the outline of the configuration of a processing liquid supply device according to this embodiment.
1 supplies a processing liquid to a discharge nozzle as a discharge unit. In this embodiment, the processing liquid supply device 100 supplies a processing liquid to a plurality of discharge nozzles 1a to 1d (four in the illustrated example). In other words, the processing liquid supply device 100 is common to the plurality of discharge nozzles 1a to 1d. However, the number of discharge nozzles to which the processing liquid is supplied by the processing liquid supply device 100 may be one.

In the following, among the components of the processing liquid supply device 100, those with common functions, such as discharge nozzles 1a to 1d, will be described with the alphabetical reference numerals omitted as appropriate. For example, "discharge nozzles 1a to 1d" will be described as "discharge nozzle 1" as appropriate.

Each of the discharge nozzles 1a to 1d discharges a processing liquid onto a wafer W (an example of a substrate) on a corresponding holding unit, the spin chuck 2. The processing liquid supplied by the processing liquid supply device 100 and discharged by the discharge nozzles 1a to 1d is, for example, a resist liquid.

The processing liquid supply device 100 includes supply pipes 150a to 150d connected to the discharge nozzles 1a to 1d. The supply pipes 150 are provided for each discharge nozzle 1, and for example, the downstream end of the supply pipe 150 is connected to the discharge nozzle 1, and the upstream end is connected to the resist liquid bottle 101.
The supply pipes 150a to 150d join together on their upstream sides to form a main supply pipe 151. Furthermore, the supply pipes 150a to 150d branch off from the main supply pipe 151 on their upstream sides to form branch supply pipes 152a and 152b, and resist solution bottles 101a and 101b are connected to the upstream ends of the branch supply pipes 152a and 152b, respectively.

The resist liquid bottle 101 is a liquid supply source that stores resist liquid inside and is replaceable. In this embodiment, multiple resist liquid bottles 101 (specifically, two) are provided, so that even while one resist liquid bottle 101 is being replaced, resist liquid can be supplied from another resist liquid bottle 101. Open/close valves V1a and V1b are installed in branch supply pipes 152a and 152b connected to the resist liquid bottles 101a and 101b.

In addition, gas supply lines 200a and 200b, which are equipped with on-off valves V2a and V2b, are also connected to the resist liquid bottles 101a and 101b. The gas supply lines 200a and 200b connect the resist liquid bottles 101a and 101b to gas supply sources 110a and 110b, which supply inert gas such as nitrogen gas, and electropneumatic regulators 111a and 111b for adjusting pressure are provided upstream of the on-off valves V2a and V2b.

In this embodiment, the first pump 102 and the resist solution bottle 101 are directly connected, with no intermediate container such as a buffer tank interposed between them. Therefore, foreign matter generated on the inner wall of the intermediate container's storage chamber does not get mixed into the resist solution being sucked into the first pump 102.

A first pump 102, a filter 103, and a flow meter 104 are provided in the supply lines 150a to 150d. In this embodiment, the first pump 102, the filter 103, and the flow meter 104 are common to the supply lines 150 and are provided in the main supply line 151. The first pump 102, the filter 103, and the flow meter 104 are provided, for example, in this order from the upstream side.

A first on-off valve V11 is provided upstream of the first pump 102 in the supply lines 150a to 150d. In this embodiment, the first on-off valve V11 is also common to all supply lines 150, and is provided upstream of the first pump 102 in the main supply line 151.

Furthermore, second on-off valves V12a to V12d are provided in the supply pipes 150a to 150d downstream of the first pump 102. In this embodiment, the second on-off valve V12 is provided for each supply pipe 150, i.e., for each discharge nozzle 1.
Furthermore, the second on-off valve V12 is integrated with the discharge nozzle 1. This makes it possible to prevent the resist solution from accumulating in the pipe connecting the second on-off valve V12 and the discharge nozzle 1, thereby preventing a decrease in cleanliness.

The first pump 102 is configured to simultaneously suck in and pump out resist liquid, and is, for example, a magnetically levitated centrifugal pump. The first pump 102 sucks in resist liquid from a resist liquid bottle 101 or the like, and pressure-feeds the resist liquid to a discharge nozzle 1 or the like. This first pump 102 can constantly pump out resist liquid at a constant flow rate and constant pressure. Note that "sucking in and pumping out resist liquid simultaneously" specifically means that the operation of sucking in resist liquid and the operation of pumping out resist liquid are performed without mechanical switching.

The filter 103 filters the resist liquid to remove particles. Specifically, the filter 103 filters the resist liquid delivered from the first pump 102 to remove particles from the resist liquid.

The processing liquid supplying apparatus 100 also includes return pipes 160a to 160d. The return pipe 160 is provided for each supply pipe 150, that is, for each discharge nozzle 1.
One end of the return pipe 160 branches off from a portion of the supply pipe 150 between the first pump 102 and the filter 103 and the second on-off valve V12. Specifically, one end of the return pipe 160 branches off from a portion of the corresponding supply pipe 150 downstream of the main supply pipe 151 and upstream of the second on-off valve V12.
On the other hand, the other end of the return pipe 160 is connected to the supply pipe 150 downstream of the first on-off valve V11 and upstream of the first pump 102 and the filter 103. Specifically, the other end of the return pipe 160 is connected to the main supply pipe 151 between the first on-off valve V11 and the first pump 102 and the filter 103.

Therefore, the return lines 160, together with a portion of the supply lines 150, form a circulation path for the resist liquid. Specifically, each return line 160, together with a corresponding portion of the supply lines 150, forms a circulation path for the resist liquid. The "portion of the supply lines 150" refers to the portion of the supply lines 150 that includes the first pump 102 and filter 103.

Furthermore, the return pipes 160 a to 160 d join at the other ends to form a main return pipe 161 .
Further, the return pipes 160a to 160d are provided with a second pump 105. In this embodiment, the second pump 105 is common to the return pipes 160a to 160d and is provided in the main return pipe 161.

Flow meters 106a-106d and third on-off valves V13a-V13d are provided between the second pump 105 and the aforementioned ends of the return lines 160a-160d. In this embodiment, a flow meter 106 and a third on-off valve V13 are provided for each return line 160, i.e., for each discharge nozzle 1. The flow meters 106 and the third on-off valves V13 are also provided in this order from the main return line 161 side.

Furthermore, a fourth on-off valve V14 is provided between the other end of the return lines 160a to 160d and the second pump 105. In this embodiment, the fourth on-off valve V14 is common to all return lines 160 and is provided in the main return line 161.

The second pump 105 is configured to be able to pump the resist liquid at least toward the one end of the return pipe 160, i.e., at least toward the discharge nozzle 1 side. Furthermore, in this embodiment, when the resist liquid flows from the one end of the return pipe 160 to the other end due to pressure pumping from the first pump 102, i.e., when the resist liquid circulates through a circulation path including the return pipe 160, the second pump 105 does not pump the resist liquid and serves as a simple pipe. Therefore, the second pump 105 is configured, for example, as a diaphragm pump.

In this embodiment, an on-off valve V15 is provided in the main supply line 151 between the first pump 102 and the filter 103.

The processing liquid supply apparatus 100 further includes a control unit M. The control unit M is, for example, a computer equipped with a CPU, memory, etc., and has a program storage unit (not shown). The program storage unit stores a program that controls the processing in the processing liquid supply apparatus 100. The program may be recorded on a computer-readable storage medium H and installed from the storage medium H into the control unit M. The storage medium H may be temporary or non-temporary. Some or all of the program may be implemented using dedicated hardware (circuit board).

Each valve provided in the processing liquid supplying apparatus 100 is an electromagnetic valve or an air-operated valve that can be controlled by a control unit M, and each valve is electrically connected to the control unit M. The control unit M is also electrically connected to the first pump 102 and the second pump 105. With this configuration, a series of processes in the processing liquid supplying apparatus 100 can be performed automatically under the control of the control unit M.
The control unit M is further connected to each flow meter, so that the control unit M can perform control based on the measurement results of the flow meter.

<Operation of the treatment liquid supply device 100>
Next, the operation of the processing liquid supply device 100 will be described with reference to FIGS. 2 to 4. FIGS. 2 to 4 are diagrams showing the states of the processing liquid supply device 100 during circulation, discharge, and replenishment, respectively. In FIGS. 2 to 4, open valves are shown in white, closed valves in black, and pipes through which resist liquid or inert gas flows are shown in bold lines, and descriptions of the open and closed states of other valves are omitted as appropriate. Note that before each of the circulation and discharge operations, the supply pipe 150 and the return pipe 160 are assumed to be filled with resist liquid. Furthermore, each of the following operations is performed under the control of the control unit M.

<Circulation>
In the processing liquid supply device 100, when the resist liquid is not supplied to any of the discharge nozzles 1, that is, when the resist liquid is not being discharged from any of the discharge nozzles 1, the resist liquid is circulated in a circulation path including the return pipe 160 so that the resist liquid does not stagnate in the supply pipe 150. Specifically, as shown in Fig. 2, the first on-off valve V11 and all of the second on-off valves V12 are closed, and the on-off valve V15, all of the third on-off valves V13, and the fourth on-off valve V14 are open. Then, the second pump is not driven, and the first pump 102 is driven.

As a result, the first pump 102 simultaneously sucks in and pumps out the resist liquid, and the resist liquid circulates through a circulation path including the return line 160 and part of the supply line 150 while being filtered by the filter 103. Specifically, the resist liquid circulates through a circulation path including the return line 160a and part of the supply line 150a, a circulation path including the return line 160b and part of the supply line 150b, a circulation path including the return line 160c and part of the supply line 150c, and a circulation path including the return line 160d and part of the supply line 150d while being filtered by the filter 103.

During circulation, the first pump 102 pumps out the resist solution so that the measurement result of the flow meter 104 becomes a desired value. Also, during circulation, the opening of the corresponding third on-off valve V13 may be adjusted to adjust the flow rate of the resist solution in each return pipe line 160 so that the measurement result of each flow meter 106 becomes a desired value.
During circulation, the resist solution also passes through the second pump 105, but the second pump is not operated and serves as a conduit through which the resist solution flows.

The above-described circulation is also performed when starting up the processing liquid supply device 100. In this case, the above-described circulation is performed so that the resist liquid is filtered multiple times by the filter 103.

By circulating the resist liquid in this manner, particles adhering to the filter 103, etc., can be prevented from becoming mixed into the resist liquid due to stagnation.

<Discharge>
In the processing liquid supply device 100, for example, the resist liquid is supplied to only one of the multiple discharge nozzles 1a to 1d, and the resist liquid is discharged from that one nozzle. During discharge from the discharge nozzle 1a, for example, the on-off valves V1a and V2a are opened, as shown in FIG. 3 . The first on-off valve V11, the on-off valve V15, and the second on-off valve V12a corresponding to the discharge nozzle 1a are opened, while the second on-off valves V12b to V12d corresponding to the other discharge nozzles 1b to 1d, which are not the target nozzles to receive the resist liquid, are closed. In this state, the resist liquid bottle 101a is pressurized with inert gas from the gas supply source 110a, and the first pump 102 is driven.
As a result, the resist liquid that has been sent from the first pump 102 and filled in the supply pipe 150a corresponding to the discharge nozzle 1a and that has passed through the filter 103 is supplied to the discharge nozzle 1a.

Furthermore, the third on-off valve V13a corresponding to the discharge nozzle 1a is opened, and the third on-off valves V13b to V13d and the fourth on-off valve V14 corresponding to the other discharge nozzles 1b to 1d that are not the target of the resist solution supply are closed, and the second pump 105 is driven.
As a result, the resist liquid that has been sent from the second pump 105 and filled in the return pipe 160a corresponding to the discharge nozzle 1a is supplied to the discharge nozzle 1a. In other words, the resist liquid flows in a direction opposite to that during the above-mentioned circulation, and is supplied to the discharge nozzle 1a via the return pipe 160a.

Therefore, when the resist liquid is discharged from the discharge nozzle 1a, the resist liquid discharged from the first pump 102 and the resist liquid discharged from the second pump 105 toward the above-mentioned one end of the return pipe 160a are mixed and supplied to the discharge nozzle 1a.
The resist liquid in the return pipe 160 has also passed through the filter 103 .

The third on-off valve V13 corresponding to the discharge nozzle 1 to which the resist liquid is supplied may be opened first, and then the corresponding second on-off valve V12 may be opened. This allows the discharge pressure of the resist liquid from the discharge nozzle 1 to be stabilized.

By the way, the filter 103 has an appropriate range for the flow rate of the resist liquid passing through the filter 103. For example, if the flow rate of the resist liquid passing through the filter 103 is too low, there is a risk that particles in the resist liquid may become partially retained within the filter 103. Furthermore, if the flow rate of the resist liquid passing through the filter 103 is high, there is a risk that particles adhering to the membrane of the filter 103 or the like may become mixed into the resist liquid.

In this regard, in this embodiment, when the resist liquid is discharged from the discharge nozzle 1a, the first pump 102, which is composed of a magnetically levitated centrifugal pump or the like, pumps out the resist liquid so that the measurement result of the flow meter 104 reaches the desired value. Therefore, it is possible to prevent the cleanliness of the resist liquid from decreasing.

It is also preferable that the flow rate of the resist liquid passing through the filter 103 is constant. This is because if the flow rate of the resist liquid passing through the filter 103 is not stable, the membrane of the filter 103 will move as the liquid passes through, causing foreign matter to be generated from the membrane.

In this regard, in this embodiment, the first pump 102 is configured, for example, as a magnetically levitated centrifugal pump, which simultaneously sucks in and pumps out the resist liquid when it is discharged from the discharge nozzle 1a.

Here, consider a case where the first pump 102, unlike this embodiment, is composed of a single diaphragm pump and is unable to simultaneously suck and dispense resist liquid. In this case, the first diaphragm pump dispenses resist liquid without suctioning it. Specifically, when discharging from the discharge nozzle 1a, the diaphragm pump displaces the resist liquid from the storage chamber formed by the diaphragm by deforming the storage chamber to reduce its volume, rather than sucking resist liquid into it. However, with this method, in order to achieve the desired flow rate of resist liquid, the pressure of the resist liquid (specifically, the pressure applied to the diaphragm) must be changed depending on the amount of resist liquid in the storage chamber. Therefore, if the first pump 102, unlike this embodiment, is composed of a single diaphragm pump and is unable to simultaneously suck and dispense resist liquid, it will be impossible to dispense resist liquid at the desired flow rate and at a constant pressure.

In contrast, in this embodiment, as described above, the first pump 102 can simultaneously suck in and discharge the resist liquid when discharging it from the discharge nozzle 1a, so there is no need to change the pressure of the resist liquid in order to discharge the resist liquid at the desired flow rate.
Therefore, in this embodiment, when the resist liquid is discharged from the discharge nozzle 1a, the first pump 102 can send out the resist liquid at a desired flow rate and at a constant pressure. That is, the flow rate of the resist liquid passing through the filter 103 can be set to a desired value, while the pressure of the resist liquid can be kept constant. Therefore, the cleanliness of the resist liquid can be further improved.

However, if the resist solution is pumped from the first pump 102 at a flow rate suitable for the filter 103, the amount of the resist solution discharged from the discharge nozzle 1a per predetermined time may become insufficient.
In this regard, in this embodiment, when the resist solution is discharged from the discharge nozzle 1a, it is sent out not only from the first pump 102 but also from the second pump 105, and the resist solution that flows in a reverse direction through the circulation path including the return pipe 160a corresponding to the discharge nozzle 1a is supplied to the discharge nozzle 1a as an auxiliary supply. Therefore, even if the resist solution is sent out from the first pump 102 at a flow rate suitable for the filter 103, the amount of the resist solution discharged from the discharge nozzle 1a per predetermined time will not be insufficient.

When the resist solution is discharged from the discharge nozzle 1a, the second pump 105 sends out the resist solution so that the measurement result of the flow meter 106a corresponding to the discharge nozzle 1a becomes a desired value, that is, a set value.
The set flow rate of the resist liquid delivered from the second pump 105 (i.e., the target value of the measurement result by the flow meter 106a) may be determined for each discharge nozzle 1. This allows the discharge amount from the discharge nozzle 1 per predetermined time to be set to a desired value, for example, to be equalized between the discharge nozzles 1, regardless of the installation state of the processing liquid supply device 100 (e.g., the distance from the discharge nozzle 1 at the supply destination to the second pump 105, the height position of the discharge nozzle at the supply destination, etc.).

<Replenishment>
In the processing liquid supply apparatus 100, after the resist liquid is discharged from the discharge nozzle 1, the second pump 105 is replenished with the resist liquid. Specifically, as shown in Fig. 4, for example, the on-off valves V1a and V2a are opened. Also, the first on-off valve V11, the on-off valve V15, and one of the third on-off valves V13 are opened, and the other third on-off valves V13, all of the second on-off valves V12, and the fourth on-off valve V14 are closed. In this state, the inside of the resist liquid bottle 101a is pressurized with inert gas from the gas supply source 110a, and the first pump 102 is driven without driving the second pump 105.
This causes the second pump to be replenished with resist liquid. After the replenishment is completed, the circulation operation described above is carried out.

Even when refilling the second pump 105, the first pump 102 pumps out resist liquid so that the measurement result of the flow meter 104 reaches the desired value. Therefore, even when refilling the second pump 105, resist liquid does not accumulate in the filter 103.

In other words, in this embodiment, the resist liquid constantly passes through the filter 103 at the same flow rate during circulation, discharge from the discharge nozzle, and refilling to the second pump 105. This makes it possible to prevent the membrane inside the filter 103 from moving. For example, when switching from a discharge operation to a refilling operation to the second pump 105, or when switching from a refilling operation to the second pump to a circulation operation, it is possible to prevent the membrane inside the filter 103 from moving. As a result, it is possible to prevent foreign matter from being generated from the membrane.

<Major Effects>
As described above, in this embodiment, one end of the conduit is branched from the supply conduit 150 between the first pump 102 and the filter 103 and the second on-off valve V12, and the other end of the conduit is provided with the return conduit 160, which is connected downstream of the first on-off valve V11 in the supply conduit 150 and upstream of the first pump 102 and the filter 103. Therefore, the return conduit 160 and the portion of the supply conduit 150 including the first pump 102 and the filter 103 form a circulation path. Therefore, when the resist solution is not being discharged from the discharge nozzle 1, the resist solution can be circulated within the circulation path, thereby preventing the resist solution from stagnating and thereby reducing the cleanliness of the resist solution. Furthermore, in this embodiment, there is no need to discharge the resist solution from the discharge nozzle 1 or the like to prevent the cleanliness of the resist solution from deteriorating, thereby reducing the consumption of the resist solution. In other words, this embodiment allows the cleanliness of the resist solution to be improved while reducing the consumption of the resist solution.

In addition, in this embodiment, a first pump 102 configured to simultaneously suck in and discharge resist liquid is installed in the supply pipe 150. Therefore, as described above, when discharging from the discharge nozzle 1a, the resist liquid can be discharged from this first pump 102 at a desired flow rate and at a constant pressure. This makes it possible to maintain a constant pressure on the resist liquid while maintaining a desired flow rate of the resist liquid passing through the filter 103. This further improves the cleanliness of the resist liquid.

Furthermore, in this embodiment, a second pump 105 is provided to pump the resist liquid toward the one end of the return pipe line. Therefore, as mentioned above, even if the first pump 102 pumps out the resist liquid at a flow rate appropriate for the filter 103, the amount of liquid discharged from the discharge nozzle 1 per given time will not be insufficient.

Furthermore, in this embodiment, one processing liquid supply device 100 supplies resist liquid to multiple discharge nozzles 1. Therefore, the state of the resist liquid discharged from the discharge nozzles 1 can be made uniform between the discharge nozzles 1.

(Modification)
In the above example, the filter 103 is provided downstream of the first pump 102 in the supply pipe 150, but it may also be provided upstream.

Also, unlike the above example, the first pump 102 may be composed of multiple diaphragm pumps. For example, in the first pump 102, resist liquid may be pumped from the first diaphragm pump while resist liquid is pumped from the second diaphragm pump to the first diaphragm pump, and during this time, resist liquid may be replenished, i.e., resist liquid may be sucked into the third diaphragm pump. This also allows liquid to pass through the filter 103 at a constant flow rate and pressure during discharge operations, etc.

The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

1 (1a to 1d) Discharge nozzle 100 Processing liquid supply device 102 First pump 103 Filter 105 Second pump 150 (150a to 150d) Supply line 160 (160a to 160d) Return line V11 First on-off valve V12 (V12a to V12a) Second on-off valve V13 (V13a to V13d) Third on-off valve V14 (V14a to V14d) Fourth on-off valve W Wafer

Claims (11)

A processing liquid supply device that supplies a processing liquid to a discharge part that discharges the processing liquid onto a substrate,
a supply pipe connected to the discharge portion;
a first pump that is interposed in the supply pipe line, that simultaneously sucks in and delivers the treatment liquid so as to deliver the treatment liquid at a constant flow rate and a constant pressure , and that pressure-feeds the treatment liquid to the discharge portion;
a first on-off valve disposed in the supply line upstream of the first pump;
a filter disposed in the supply pipe line for filtering the treatment liquid;
a second on-off valve disposed in the supply line downstream of the first pump;
a return line having one end branched off from a portion of the supply line between the first pump and the filter and the second on-off valve, and having the other end connected to the supply line downstream of the first on-off valve and upstream of the first pump and the filter;
a second pump disposed in the return pipe line and pressure-feeding the treatment liquid toward the one end of the return pipe line;
a third on-off valve interposed between the one end of the return pipe and the second pump;
a fourth on-off valve interposed between the other end of the return pipe and the second pump. The processing liquid supply apparatus of claim 1, further comprising a control unit that controls the first on-off valve, the second on-off valve, the third on-off valve, the fourth on-off valve, the first pump, and the second pump. The processing liquid supply device of claim 2, wherein the control unit controls the first on-off valve, the second on-off valve, the third on-off valve, the fourth on-off valve, the first pump, and the second pump so that, during discharge from the discharge unit, the processing liquid delivered from the first pump and the processing liquid delivered from the second pump toward the one end of the return pipe are mixed and supplied to the discharge unit. The processing liquid supply device of claim 3, wherein the control unit, when discharging from the discharge unit, opens the third on-off valve and then the second on-off valve. the return pipe, together with a portion of the supply pipe including the first pump and the filter, constitutes a circulation path for the treatment liquid;
5. The processing liquid supply device according to claim 2, wherein the control unit controls the first on-off valve, the second on-off valve, the third on-off valve, the fourth on-off valve, the first pump, and the second pump so that the processing liquid circulates through the circulation path at times other than when the processing liquid is being discharged from the discharge unit. supplying the treatment liquid to the plurality of discharge portions;
the supply pipe line, the second on-off valve, the third on-off valve, and the return pipe line are provided for each of the discharge portions,
The supply pipelines join downstream to form a main supply pipeline,
The return pipes are joined at the other end to form a main return pipe,
the first on-off valve, the first pump, and the filter are interposed in the main supply line;
6. The processing liquid supplying apparatus according to claim 1, wherein the second pump and the fourth on-off valve are disposed in the main return line. The processing liquid supply device of claim 6, wherein each of the return lines, together with the corresponding supply line, forms a circulation path for the processing liquid. The processing liquid supply device according to claim 6 or 7, wherein when liquid is being discharged from one of the discharge portions, the second on-off valve and the third on-off valve for the other discharge portions are closed. The treatment liquid supply device according to any one of claims 6 to 8, wherein the set flow rate of the treatment liquid delivered from the second pump is determined for each discharge unit. The treatment liquid supply device described in any one of claims 1 to 9, wherein the discharge section is integrated with the second on-off valve. 1. A processing liquid supplying method for supplying a processing liquid to a discharge section that discharges the processing liquid onto a substrate using a processing liquid supplying device,
The processing liquid supply device
a supply pipe connected to the discharge portion;
a first pump that is interposed in the supply pipe line, that simultaneously sucks in and delivers the treatment liquid so as to deliver the treatment liquid at a constant flow rate and a constant pressure , and that pressure-feeds the treatment liquid to the discharge portion;
a first on-off valve disposed in the supply line upstream of the first pump;
a filter disposed in the supply pipe line for filtering the treatment liquid;
a second on-off valve disposed in the supply line downstream of the first pump;
a return line having one end branched off from a portion of the supply line between the first pump and the filter and the second on-off valve, and having the other end connected to the supply line downstream of the first on-off valve and upstream of the first pump and the filter;
a second pump disposed in the return pipe line and pressure-feeding the treatment liquid toward the one end of the return pipe line;
a third on-off valve interposed between the one end of the return pipe and the second pump;
a fourth on-off valve interposed between the other end of the return pipe and the second pump,
the return pipe, together with a portion of the supply pipe including the first pump and the filter, constitutes a circulation path for the treatment liquid;
When the treatment liquid is discharged from the discharge portion, the treatment liquid pressure-fed from the first pump and the treatment liquid pressure-fed from the second pump toward the one end of the return pipe line are mixed and supplied to the discharge portion;
The treatment liquid supply method includes causing the treatment liquid pressure-fed from the first pump to pass through the second pump and circulate through the circulation path at times other than when the treatment liquid is being discharged from the discharge portion.