Liquid supply device and liquid supply method

A liquid supply device includes: a storage tank configured to store a processing liquid including a first processing liquid (sulfuric acid) and a second processing liquid (hydrogen peroxide solution); a circulation path having a first pipeline through which the processing liquid passes in a horizontal direction, and configured to circulate the processing liquid stored in the storage tank; a branch path configured to supply the processing liquid to a processing unit; and a branching part having an opening for allowing the processing liquid to flow out from the first pipeline to the branch path, wherein the opening is formed in the branching part and formed below a periphery of the first pipeline when the first pipeline is viewed in section.

This is a National Phase Application under 35 U.S.C. 371 as a national stage of PCT/JP2018/011742, filed Mar. 23, 2018, an application claiming the benefit of priority from Japanese Patent Application No. 2017-076297, filed on Apr. 6, 2017, and Japanese Patent Application No. 2018-029284, filed on Feb. 22, 2018, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a technique for supplying a processing liquid to a substrate processing apparatus.

BACKGROUND

A substrate processing apparatus that processes a substrate such as a semiconductor wafer or a glass substrate using a liquid mixture obtained by mixing a first processing liquid and a second processing liquid stored in tanks and supplied from the tanks is known in the related art.

In this type of substrate processing apparatus, in some cases, the first processing liquid may be recovered and reused by returning the used liquid mixture to the tank that stores the first processing liquid. The first processing liquid recovered in the tank is mixed with the second processing liquid again through a circulation path and supplied to the substrate (see Patent Document 1).

PRIOR ART DOCUMENTS

Patent Documents

However, by returning the used liquid mixture, not only the first processing liquid but also the second processing liquid is contained in the tank. A mixture of the first processing liquid and the second processing liquid may be foamed due to reaction of the two liquids, the influence of heat, or the like. In order to improve the performance of substrate processing, it is preferable to supply a processing liquid that does not include foams.

The present disclosure provides some embodiments of a liquid supply device and a liquid supply method capable of preventing foams from being included in a processing liquid supplied to a substrate processing apparatus.

SUMMARY

A liquid supply device according to one aspect of embodiment is a liquid supply device for supplying a processing liquid to a substrate processing apparatus. The liquid supply device includes: a storage configured to store a processing liquid including a first processing liquid and a second processing liquid; a circulation path having a first pipeline through which the processing liquid passes in a horizontal direction, and configured to circulate the processing liquid stored in the storage; a branch path configured to supply the processing liquid to the substrate processing apparatus; and a branching part having an opening for allowing the processing liquid to flow out from the first pipeline to the branch path. The opening is formed in the branching part and formed below a periphery of the first pipeline when the first pipeline is viewed in section.

According to one aspect of the embodiment, it is possible to achieve an effect of preventing foams from being included in a processing liquid supplied to a substrate processing apparatus.

DETAILED DESCRIPTION

Embodiments of a liquid supply device and a liquid supply method disclosed in the present disclosure will now be described in detail with reference to the accompanying drawings. It is noted that the present disclosure is not limited by embodiments described below.

First Embodiment

FIG.1is a view illustrating a schematic configuration of a substrate processing system according to a first embodiment. In the following, in order to clarify the positional relationship, an X axis, a Y axis, and a Z axis that are orthogonal to one another are defined, and it is assumed that the positive direction of the Z axis is an upward vertical direction.

As illustrated inFIG.1, the substrate processing system1includes a loading/unloading station2and a processing station3. The loading/unloading station2and the processing station3are arranged adjacent to each other.

The loading/unloading station2includes a carrier stage11and a transfer part12. A plurality of carriers C in which a plurality of wafers W (substrates) is accommodated in a horizontal position is mounted on the carrier stage11.

The transfer part12is disposed adjacent to the carrier stage11and includes a substrate transfer device13and a delivery part14therein. The substrate transfer device13includes a substrate holding mechanism that holds the wafers W. Further, the substrate transfer device13can move in a horizontal direction and the vertical direction and rotate around the vertical axis. The substrate transfer device13transfers the wafers W between the carriers C and the delivery part14by using the substrate holding mechanism.

The processing station3is disposed adjacent to the transfer part12. The processing station3includes a transfer part15and a plurality of processing units16. The processing units16are arranged side by side in both sides of the transfer part15.

The transfer part15includes a substrate transfer device17therein. The substrate transfer device17includes a substrate holding mechanism that holds the wafers W. Further, the substrate transfer device17can move in the horizontal direction and the vertical direction, and can rotate around the vertical axis. The substrate transfer device17transfers the wafers W between the delivery part14and the processing unit16by using the substrate holding mechanism.

The processing unit16performs predetermined substrate processes on the wafers W transferred by the substrate transfer device17.

The substrate processing system1further includes a controller4. The controller4is, for example, a computer and includes a control part18and a storage part19. The storage part19stores a program for controlling various processes executed in the substrate processing system1. The control part18controls the operation of the substrate processing system1by reading and executing the program stored in the storage part19.

Such a program may be recorded on a computer-readable storage medium and may be installed in the storage part19of the controller4from the storage medium. Examples of the computer-readable storage medium may include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnetic optical disk (MO), a memory card, and the like.

In the substrate processing system1configured as described above, first, the substrate transfer device13of the loading/unloading station2takes out a wafer W from the carrier C mounted on the carrier stage11and places the taken-out wafer W on the delivery part14. The wafer W placed on the delivery part14is taken out from the delivery part14by the substrate transfer device17of the processing station3and is loaded into the processing unit16.

The wafer W loaded into the processing unit16is processed by the processing unit16. Then, the wafer W is unloaded from the processing unit16by the substrate transfer device17, and placed on the delivery part14. Then, the processed wafer W placed on the delivery part14is returned to the carrier C of the carrier stage11by the substrate transfer device13.

Next, a schematic configuration of the processing unit16will be described with reference toFIG.2.FIG.2is a view illustrating a schematic configuration of the processing unit16.

As illustrated inFIG.2, the processing unit16includes a chamber20, a substrate holding mechanism30, a processing fluid supply40, and a recovery cup50.

The chamber20accommodates the substrate holding mechanism30, the processing fluid supply40, and the recovery cup50. A fan filter unit (FFU)21is installed on the ceiling of the chamber20. The FFU21forms a down flow in the chamber20.

The substrate holding mechanism30includes a holder31, a support pillar32, and a driver33. The holder31holds the wafer W in a horizontal position. The support pillar32extends in the vertical direction, and has proximal end rotatably supported by the driver33and a distal end supporting the holder31in a horizontal position. The driver33rotates the support pillar32around a vertical axis. The substrate holding mechanism30rotates the holder31by rotating the support pillar32using the driver33, thereby rotating the wafer W held by the holder31.

The processing fluid supply40supplies a processing fluid to the wafer W. The processing fluid supply40is connected to a processing fluid supply source70.

The recovery cup50is arranged so as to surround the holder31and collects a processing liquid scattered from the wafer W by the rotation of the holder31. A liquid drain port51is formed at the bottom of the recovery cup50, and the processing liquid collected by the recovery cup50is discharged from the liquid drain port51to the outside of the processing unit16. Further, an exhaust port52for discharging a gas supplied from the FFU21to the outside of the processing unit16is formed at the bottom of the recovery cup50.

Next, a specific configuration of a processing liquid supply system in the substrate processing system1according to the embodiment will be described with reference toFIG.3.FIG.3is a view illustrating a specific configuration of a processing liquid supply system in the substrate processing system1according to the embodiment.

The following description will be given with a configuration of the processing liquid supply system in a case where sulfuric acid is used as a first processing liquid, hydrogen peroxide solution is used as a second processing liquid, and a sulfuric acid hydrogen peroxide mixture (SPM), which is a mixture of the first and second liquids, is supplied to the wafer W.

As illustrated inFIG.3, the processing fluid supply source70includes a sulfuric acid supply system including a storage tank102that stores sulfuric acid, a circulation path104that exits from the storage tank102and returns to the storage tank102, and a plurality of branch paths112that branch from the circulation path104and is connected to the respective processing units16(substrate processing apparatus).

The processing liquid supply system of the first embodiment is to recover and reuse the SPM supplied to the wafer W, as will be described later. To this end, not only sulfuric acid but also hydrogen peroxide solution is stored in and passed through the sulfuric acid supply system. Therefore, in the first embodiment, a liquid stored in and passed through the sulfuric acid supply system is defined as a processing liquid containing sulfuric acid (the first processing liquid) and hydrogen peroxide solution (the second processing liquid), which will be described below.

In the circulation path104, a pump106, a filter part108, a heater109, a defoamer301, and a gas discharger302are arranged in this order from the upstream side. The pump106forms a circulation flow that exits from the storage tank102, passes through the circulation path104, and returns to the storage tank102. The filter part108removes unnecessary substances such as particles contained in sulfuric acid. The heater109is controlled by the control part18to heat the sulfuric acid circulating through the circulation path104to a set temperature.

The circulation path104includes a first pipeline104athrough which the processing liquid passes in the horizontal direction (positive direction of the X axis), and a second pipeline104b, which is located in the downstream of the first pipeline104aand through which the processing liquid passes in the downward direction (negative direction of the Z axis). Details of the defoamer301and the gas discharger302will be described later.

The plurality of branch paths112are connected to the first pipeline104ain the circulation path104. The branch paths112are respectively connected to a mixer45(which will be described later) of the respective processing units16and supply sulfuric acid flowing through the circulation path104to the respective mixer45. Each branch path112is provided with a valve113. Each branch path112is also provided with a flow meter303for measuring the flow rate of the processing liquid flowing through the pipeline. Each branch path112is branched at a branching part112afrom the circulation path104. Details of the branching part112awill be described later.

The processing fluid supply source70further includes a hydrogen peroxide solution supply system including a hydrogen peroxide solution supply path160, a valve161, and a hydrogen peroxide solution supply source162. One end of the hydrogen peroxide solution supply path160is connected to the hydrogen peroxide solution supply source162via the valve161, and the other end thereof is connected to the mixer45(which will be described later) of the processing unit16. The processing fluid supply source70supplies hydrogen peroxide solution, which is supplied from the hydrogen peroxide solution supply source162, to the mixer45of the processing unit16via the hydrogen peroxide solution supply path160.

The processing fluid supply source70further includes a supply path170, a valve171, and a sulfuric acid supply source172. One end of the supply path170is connected to the sulfuric acid supply source172via the valve171, and the other end thereof is connected to the storage tank102. The sulfuric acid supply source172supplies sulfuric acid. The processing fluid supply source70supplies sulfuric acid, which is supplied from the sulfuric acid supply source172, to the storage tank102via the supply path170. The storage tank102is provided with a liquid level sensor (not shown). When it is detected by the liquid level sensor that the liquid level of the storage tank102has reached a lower limit value, a predetermined amount of sulfuric acid is replenished into the storage tank102via the supply path170. As a result, the concentration and amount of liquid in the storage tank102are kept constant.

Although not shown, the processing fluid supply source70further includes a rinse liquid supply path for supplying a rinse liquid to the processing unit16. For example, de-ionized wafer (DIW) may be used as the rinse liquid.

The processing unit16includes the mixer45. The mixer45mixes the sulfuric acid supplied from the branch path112and the hydrogen peroxide solution supplied from the hydrogen peroxide solution supply path160to generate an SPM which is a liquid mixture, and supplies the generated SPM to the processing fluid supply40(seeFIG.2). The mixer45may be integrated into the processing fluid supply40.

The liquid drain port51of each processing unit16is connected to a discharge path54via a branch path53. The SPM used in each processing unit16is discharged from the liquid drain port51to the discharge path54via the branch path53.

Here, the supply of the SPM and the supply of the rinse liquid are performed using the processing fluid supply40. However, the processing unit16may include a separate processing fluid supply for supplying the rinse liquid.

The substrate processing system1further includes a switch80, a recovery path114, and a discard path115. The switch80is connected to the discharge path54, the recovery path114, and the discard path115and switches an inflow destination of the used SPM flowing through the discharge path54between the recovery path114and the discard path115according to control of the control part18.

The recovery path114has one end connected to the switch80and the other end connected to the storage tank102. In the recovery path114, a recovery tank116, a pump117, and a filter118are arranged in this order from the upstream side. The recovery tank116temporarily stores the used SPM. The pump117forms a flow of the used SPM stored in the recovery tank116to the storage tank102. The filter118removes contaminants such as particles contained in the used SPM.

The discard path115is connected to the switch80and discharges the used SPM, which inflows from the discharge path54via the switch80, to the outside of the substrate processing system1.

Next, the contents of substrate processing executed by the processing unit16according to the first embodiment will be described with reference toFIG.4.FIG.4is a flowchart illustrating an example of a substrate processing procedure executed by the processing unit16according to the first embodiment. The processing procedure illustrated inFIG.4is executed under control of the control part18.

First, in the processing unit16, a wafer (W) loading process is performed (step S101). Specifically, a wafer W is loaded into the chamber20(seeFIG.2) of the processing unit16by the substrate transfer device17(seeFIG.1) and is held by the holder31. Thereafter, the processing unit16rotates the holder31at a predetermined rotation speed (for example, 50 rpm).

Subsequently, in the processing unit16, an SPM supplying process is performed (step S102). In the SPM supplying process, an SPM is supplied from the processing fluid supply40to the upper surface of the wafer W by opening the valve113and the valve161for a predetermined period of time (for example, 30 seconds). The SPM supplied to the wafer W is spread on the surface of the wafer W by a centrifugal force generated by the rotation of the wafer W.

In such an SPM supplying process, for example, a resist formed on the upper surface of the wafer W is removed using the strong oxidizing power of Caro's acid contained in the SPM and the reaction heat of sulfuric acid and hydrogen peroxide solution.

The flow rates of sulfuric acid and hydrogen peroxide solution are determined depending on the mixing ratio between sulfuric acid and hydrogen peroxide solution. Since the ratio of sulfuric acid in SPM is higher than that of hydrogen peroxide solution, the flow rate of sulfuric acid is set to be higher than that of hydrogen peroxide solution.

When the SPM supplying process in step S102is completed, the processing unit16performs a rinsing process (step S103). In the rinsing process, a rinse liquid (for example, DIW) is supplied from the processing fluid supply40to the upper surface of the wafer W. The DIW supplied to the wafer W is spread on the surface of the wafer W by a centrifugal force generated by the rotation of the wafer W. As a result, the SPM remaining on the wafer W is washed away by the DIW.

Subsequently, in the processing unit16, a drying process is performed (step S104). In the drying process, the wafer W is rotated at a predetermined rotation speed (for example, 1,000 rpm) for a predetermined period of time. As a result, the DIW remaining on the wafer W is removed and the wafer W is dried. Thereafter, the rotation of the wafer W is stopped.

Then, in the processing unit16, an unloading process is performed (step S105). In the unloading process, the wafer W held by the holder31is delivered to the substrate transfer device17. When this unloading process is completed, the substrate processing for one wafer W is completed.

Next, the contents of a used SPM recovery process will be described with reference toFIG.5.FIG.5is a flowchart illustrating an example of a recovery processing procedure.FIG.5illustrates a recovery processing procedure when the discharge path54and the discard path115are in communication at the start of the SPM supplying process. The processing procedure illustrated inFIG.5is controlled by the control part18.

As illustrated inFIG.5, the control part18determines whether or not a first time has elapsed from the start of the SPM supplying process (seeFIG.4) by the processing unit16(step S201). Here, the first time is set to a time longer than a time from when the valves113and161are opened to when the flow rates of sulfuric acid and hydrogen peroxide solution are stabilized.

In the first embodiment, the time when both the valve113and the valve161are opened is defined as the start time of the SPM supplying process. However, the definition of the start time of the SPM supplying process is not limited thereto. The start time of the SPM supplying process may be differently defined, for example, by a time when the control part18sends an opening instruction signal to the valves113and161, a time when the SPM reaches the wafer W and the like.

The control part18repeats the determining process of step S201until the first time elapses (“No” in step S201). At this time, since the discharge path54communicates with the discard path115, the used SPM is discarded from the discard path115to the outside.

Subsequently, when it is determined in step S201that the first time has elapsed (“Yes” in step S201), the control part18controls the switch80to switch the inflow destination of the used SPM from the discard path115to the recovery path114(step S202). As a result, the used SPM flows from the discharge path54into the recovery path114and is returned to the storage tank102.

Subsequently, the control part18determines whether or not a second time has elapsed after the first time has elapsed (step S203). The second time is set to a time when a recovery rate of the used SPM becomes a predetermined used SPM recovery rate X1. The control part18repeats the determining process of step S203until the second time elapses (“No” in step S203).

Subsequently, when it is determined in step S203that the second time has elapsed (“Yes” in step S203), the control part18switches the inflow destination of the used SPM from the recovery path114to the discard path115(step S204). As a result, the used SPM is discarded from the discard path115to the outside.

In this way, in the substrate processing system1according to the embodiment, the used SPM is recovered at a predetermined recovery rate except for a predetermined period after the start of the SPM supplying process and a predetermined period before the end of the SPM supplying process. As a result, the used SPM can be recovered at a stable concentration and flow rate, and the actual recovery rate of the used SPM can be matched with the predetermined recovery rate as much as possible. Therefore, according to the substrate processing system1according to the embodiment, it is possible to reduce consumption of sulfuric acid as much as possible.

In addition, when the discharge path54and the recovery path114are in communication with each other at the start of the SPM supplying process, the control part18may perform a process of switching the inflow destination of the used SPM from the recovery path114to the discard path115before the start of the SPM supplying process.

Next, a foam removing process of the first embodiment will be described. A processing liquid containing sulfuric acid (the first processing liquid) and hydrogen peroxide solution (the second processing liquid) is circulated in the circulation path104constituting the sulfuric acid supply system of the first embodiment. The reaction of sulfuric acid and hydrogen peroxide solution also occurs in the circulation path104, and the processing liquid foams at that time. Further, since the inside of the circulation path104is kept in a relatively high temperature state, the SPM and the contained hydrogen peroxide solution are foamed over time.

If the generated foam is not removed, the processing liquid containing the foam flows from the circulation path104into the branch path112and is supplied to the wafer W through the mixer45of the processing unit16. When the processing liquid containing the foam is supplied to the wafer W, discharge of the foam causes liquid scattering and mists, which affects the processing. In addition, erroneous measurement of the flow meter303in the branch path112is likely to occur. In the first embodiment, the branch path112is configured to perform a feedback adjustment of the flow rate based on the measurement results of the flow meter303. In such a feedback system, if the flow meter303produces erroneous measurements and outputs a significantly larger flow rate, control for reducing the flow rate is executed and there is a concern that an SPM of a desired amount and mixing ratio may not be supplied to the wafer W. Further, as illustrated in the flowchart ofFIG.5described above, in the first embodiment, the switching timing of the inflow destination of the used SPM is controlled on the premise that the SPM is accurately supplied to the wafer W according to a prescribed flow rate. Since a deviation in the feedback adjustment may occur even when the flow meter303produces minor erroneous measurements, the SPM is not accurately supplied to the wafer W according to the prescribed flow rate and there is a concern that the concentration of sulfuric acid in the storage tank102is also changed.

Since the above problems may occur, it is apparent that it is preferable to supply a processing liquid containing no foam in order to improve the performance of the SPM processing. In the first embodiment, a foam removing process using a plurality of foam removal parts is performed to prevent foams from being present in a processing liquid supplied to a substrate via a circulation path.

The plurality of foam removal parts in the first embodiment are the filter part108, the defoamer301, the branching part112a, and the gas discharger302. The details of each foam removal parts will be described below.

FIG.6is a view illustrating a configuration example of the filter part108. The filter part108is composed of two filters108awhich are arranged in parallel with respect to the circulation path104, as illustrated inFIG.3.

InFIG.6, a filtering member1081, which is made of a synthetic resin or the like, captures contaminants such as particles contained in the processing liquid, while passing the processing liquid only. A first processing liquid chamber1082is a closed region provided on the primary side of the filter108aand temporarily stores the processing liquid flowing in from the circulation path104on the side connected to the storage tank102. A second processing liquid chamber1083is a closed region provided on the secondary side of the filter108a, temporarily stores the processing liquid that has passed through the filtering member1081, and flows the processing liquid out to the circulation path104again.

A vent pipe1084for allowing a gas to pass therethrough is provided on the upper surface of the first processing liquid chamber1082. The vent pipe1084is provided with a throttle1085for adjusting the amount of gas passing, and the adjusted flow rate of the gas is discharged to a gas flow path304and is returned to the storage tank102.

By measuring the pressure of the pump106, the pressure loss due to the filtering member1081, and the like in advance and adjusting the throttle amount of the throttle1085based on the relationship therebetween, the foams contained in the processing liquid in the first processing liquid chamber1082can be directed upward without passing through the filtering member1081. The foams that have arrived at the top gather and are discharged from the vent pipe1084. In this way, the filter part108functions, during the supply or circulation of the processing liquid, as a first foam removal part that mainly removes foams from the processing liquid stored in the storage tank102and outflows the processing liquid, from which the foams are removed, toward the heater109.

In addition, in the first embodiment, by arranging the filters108ain parallel with respect to the circulation path104, a pressure acting on the filters108acan be distributed as compared with a case where only one filter108ais provided. In addition, the discard diameter of the vent pipe1084can be substantially widened. Thus, it is possible to efficiently remove the foams as a whole while suppressing a decrease in the flow rate of the processing liquid generated by the pump106.

FIG.7is a view illustrating a configuration example of the defoamer301. Although the processing liquid contains no foam immediately after passing through the filter part108, since the hydrogen peroxide solution remains in the processing liquid, the sulfuric acid and the hydrogen peroxide solution react to generate foams. Further, the heater109raises the temperature of the processing liquid and promotes the foaming. The defoamer301removes such foams of the processing liquid.

As illustrated inFIG.7, the defoamer301is composed of a defoaming chamber3011, an upper inlet3012connected to the circulation path104on the heater109side, a lower outlet3013connected to the circulation path104on the first pipeline104aside, and a gas discharge port3014.

The processing liquid that flowed into the defoaming chamber3011via the upper inlet3012is temporarily stored in the defoaming chamber3011. The stored processing liquid flows out to the circulation path104via the lower outlet3013.

Here, the defoaming chamber3011has a cylindrical shape, and has a sectional area larger than that of the circulation path104. Accordingly, the processing liquid that flowed into the defoaming chamber3011has a relatively reduced flow velocity and moves downward as a whirling flow. Here, the foams present in the processing liquid move upward against the traveling direction of the processing liquid, and gather at the upper portion of the defoaming chamber3011. The gathered foams are discharged as a gas to the gas flow path304through the gas discharge port3014. In this manner, the defoamer301functions, during the supply or circulation of the processing liquid, as a second foam removal part that removes the foams from the processing liquid heated by the heater109and outflows the processing liquid, from which the foams are removed, toward the first pipeline104a.

FIG.8is a view illustrating a configuration example of the branching part112a. As illustrated inFIG.8, the branching part112ahas an opening121through which the processing liquid flows out from the first pipeline104ato the branch path112. In the branching part112a, the opening1121is formed below the periphery of the first pipeline104awhen the first pipeline104ais viewed in section. The opening1121has the same sectional area as that of the branch path112.

Since the first pipeline104aextends in the horizontal direction, as the processing liquid passes through the first pipeline104a, the foams move upward in the pipeline and gather at the upper portion of the pipeline to form a gas region A. On the other hand, the foams do not move downward and do not enter the opening1121in the branching part112a. In this way, the branching part112afunctions, during the supply or circulation of the processing liquid, as a third foam removal part that removes relatively small foams from the processing liquid passing through the first pipeline104aand outflows the processing liquid, from which the foams are removed, toward the branch path112.

FIG.9is a view illustrating a configuration example of the gas discharger302. As illustrated inFIG.9, the gas discharger302is placed at the boundary between the first pipeline104aand the second pipeline104b. The gas discharger302includes a gas collection chamber3021, a processing liquid inlet3022, a processing liquid outlet3023, and a gas discharge port3024. The gas discharge port3024is formed on the upper surface (ceiling) of the gas collection chamber3021such that a gas is discharged from the circulation path104to the outside.

As described above, the foams of the processing liquid flowing through the first pipeline104amove upward, and the foams gather at the upper portion form the gas region A. The gas region A and the processing liquid containing some foams flow into the gas collection chamber3021via the processing liquid inlet3022.

The gas that flowed into the gas collection chamber3021immediately gathers at the upper portion of the gas collection chamber3021. The processing liquid that flowed into the gas collection chamber3021flows under the influence of gravity toward the processing liquid outlet3023. In this course, the foams present in the processing liquid move upward of the gas collection chamber3021against the flow direction and gather in the upper portion of the gas collection chamber3021.

The gas gathering in the upper portion of the gas collection chamber3021is discharged to the gas flow path304via the gas discharge port3024. In this way, the gas discharger302functions, during the supply or circulation of the processing liquid, as a fourth foam removal part that removes the foams from the processing liquid that has passed through the first pipeline104aand removes the gas, which has already been separated from the processing liquid, and outflows the processing liquid, from which the foams are removed, toward the second pipeline104b.

As described above, the filter part108functions as the first foam removal part, the defoamer301functions as the second foam removal part, the branching part112afunctions as the third foam removal part, and the gas discharger302functions as the fourth foam removal part. With such a configuration, it is possible to achieve a superposed effect of removing foams by the plurality of foam removal parts during the circulation or supply of the processing liquid.

The arrangement of the foam removal parts also provides individual effects of the foam removal parts. First, there is an effect that foams are less likely to flow into the heater109due to the removal of foams by the filter part108, and heating abnormalities are accordingly less likely to occur. In addition, there is an effect that it is possible to prevent foams generated by the heating operation of the heater from flowing into the branch path due to the removal of foams by the defoamer301. In addition, since the branching part112ais disposed near the flow meter303, erroneous measurement of the flow meter303caused by relatively small foams does not occur. In addition, since the first pipeline104aextends horizontally, there is an effect that foams and liquid can be separated from each other to some extent before flowing into the subsequent gas discharger302and the removal performance of the gas discharger302is improved. In addition, there is an effect that the foams of the processing liquid in the storage tank102can be reduced in advance prior to recirculation due to the removal of foams by the gas discharger302.

As described above, according to the first embodiment, the processing liquid supplied to the processing unit does not contain foams. As a result, liquid scattering and mists caused by relatively large foams at the time of supply of the processing liquid to the wafer W are not generated, and a reduction in accuracy of recovery control due to erroneous measurement of the flow meter can be avoided, thereby achieving further high performance of wafer processing.

Next, modification of the first embodiment will be described with reference toFIGS.10A and10B.FIG.10Ais a view illustrating a modification of the opening1121formed in the first pipeline104a.FIG.10Bis a view illustrating a modification of the first pipeline104a.

In the first embodiment described above, the position of the opening1121formed in the first pipeline104ais not limited to the directly-below position as illustrated inFIG.8. For example, as illustrated inFIG.10A, the position of the opening1121may be any lower position where relatively small foams do not enter, such as an oblique position.

Further, the first pipeline104ais not limited to the horizontal direction as illustrated inFIG.3, but may be inclined obliquely as long as the gas and the processing liquid can be separated from each other, as illustrated inFIG.10B. Moreover, the second pipeline104bconnected to the gas discharger302may also be connected at an oblique position instead of a position directly below, and the second pipeline104bitself may be inclined as long as the processing liquid can flow by the action of gravity.

Second Embodiment

A second embodiment shows another configuration example of the first pipeline.FIG.11is a view illustrating a configuration example of the first pipeline according to the second embodiment.

As illustrated inFIG.11, a first pipeline104alincludes a first portion201and a second portion202. The first portion201is a portion having a first sectional area in the first pipeline104a1. The second portion202is provided in the middle of the first portion201and has a second sectional area larger than the first sectional area. The sectional area as used herein refers to the area of a section obtained by cutting the first pipeline104alalong the radial direction. That is, the second portion202is a portion having a larger diameter than the first portion201.

The opening1121of the branch path112is formed below the periphery of the second portion202.

As described above, since the foams move in the upper portion of the first pipeline104al, as the diameter of the first pipeline104alis increased, the foams will be located away from the opening1121formed below the periphery of the first pipeline104a1(the second portion202). Therefore, by providing the second portion202in the first pipeline104a1and forming the opening1121below the periphery of the second portion202, it is possible to suppress the foams from entering the opening1121. That is, it is possible to remove the foams from the processing liquid passing through the first pipeline104al.

The first portion201includes an upstream first portion211provided in the upstream of the second portion202and a downstream first portion212provided in the downstream of the second portion202. As illustrated inFIG.11, the downstream first portion212is disposed at a position higher than the upstream first portion211. In this way, by disposing the downstream first portion212at a position higher than the upstream first portion211, it may be possible to suppress the foams from staying in the upper portion of the second portion202.

The second portion202includes an intermediate portion221, an upstream second portion222, and a downstream second portion223.

The intermediate portion221has a lower surface221ahaving the same height position to the height position of a lower surface211aof the upstream first portion211, and an upper surface221bhaving the same height position to the height position of an upper surface212bof the downstream first portion212. The intermediate portion221extends along the horizontal direction.

The upstream second portion222is provided between the upstream first portion211and the intermediate portion221, and has an upper surface222binclined upward from an upper surface211bof the upstream first portion211toward the upper surface221bof the intermediate portion221. A lower surface222aof the upstream second portion222has the same height position to those of the lower surface211aof the upstream first portion211and the lower surface221aof the intermediate portion221.

The downstream second portion223is provided between the intermediate portion221and the downstream first portion212, and has a lower surface223ainclined upward from the lower surface221aof the intermediate portion221toward a lower surface212aof the downstream first portion212. An upper surface223bof the downstream second portion223has the same height position to those of the upper surface221bof the intermediate portion221and the upper surface212bof the downstream first portion212.

The opening1121of the branch path112is formed below the periphery of the intermediate portion221.

As described above, the upstream second portion222, which is a connection portion between the upstream first portion211and the intermediate portion221, and the downstream second portion223, which is a connection portion between the intermediate portion221and the downstream first portion212, are tapered. Thus, the sectional area of the first pipeline104alcan be gradually changed between the first portion201and the second portion202. Therefore, it may be possible to suppress turbulence in the flow of the processing liquid at the connection portion between the upstream first portion211and the intermediate portion221and at the connection portion between the intermediate portion221and the downstream first portion212.

Further, by tapering the upstream second portion222, which is the connection portion between the upstream first portion211and the intermediate portion221, it is possible to suppress a so-called “flow separation” in which the flow of the processing liquid is interrupted when the processing liquid flows from the upstream first portion211into the second portion202. When the flow separation occurs, foams may be generated at a separated portion. Therefore, by suppressing the flow separation, it is possible to suppress the foams from entering the opening1121of the branch path112.

In addition, since the flow of foams heading obliquely upward is formed in the upstream second portion222, the foams are less likely to move toward the opening1121formed below the periphery of the intermediate portion221. This also can suppress the foams from entering the opening1121of the branch path112.

Further, by disposing the lower surface211aof the upstream first portion211, the lower surface222aof the upstream second portion222, and the lower surface221aof the intermediate portion221at the same height position, it is possible to suppress the flow of the processing liquid directing downward from being formed in the second portion202. Therefore, it is possible to suppress the foams from being dragged by the flow of the processing liquid directing downward and approaching the opening1121.

Further, by disposing the upper surface221bof the intermediate portion221, the upper surface223bof the downstream second portion223, and the upper surface212bof the downstream first portion212at the same height position, it is possible to suppress the foams from staying in the upper portion of the second portion202.

As described above, with the first pipeline104a1according to the second embodiment, by providing the second portion202having a larger sectional area than that of the first portion201and forming the opening1121below the periphery of the second portion202, it is possible to suppress the foams from entering the opening1121.

The configurations of the first portion and the second portion are not limited to the examples described above. Modifications of the first pipeline in the second embodiment will be described below.FIGS.12to14are views illustrating configuration examples of the first pipeline according to first to third modifications of the second embodiment.

As illustrated inFIG.12, in a first pipeline104a2according to the first modification, the upstream first portion211and the downstream first portion212are disposed at the same height position. The second portion202extends uniformly and horizontally from the end portion on the upstream first portion211side to the end portion on the downstream first portion212side.

A lower surface202aof the second portion202is disposed at the height position lower than those of the lower surface211aof the upstream first portion211and the lower surface212aof the downstream first portion212. In addition, an upper surface202bof the second portion202is disposed at the height position higher than those of the upper surface211bof the upstream first portion211and the upper surface212bof the downstream first portion212. The opening1121of the branch path112is formed below the periphery of the second portion202.

As described above, by providing the second portion202having a larger sectional area than that of the first portion201in the first pipeline104a2and forming the opening1121below the periphery of the second portion202, it is possible to suppress the foams from entering the opening1121. That is, it is possible to remove the foams from the processing liquid passing through the first pipeline104a2.

Further, as illustrated inFIG.13, in a first pipeline104a3according to the second modification, like the first pipeline104a2according to the first modification, the upstream first portion211and the downstream first portion212are disposed at the same height position.

The second portion202includes the intermediate portion221, the upstream second portion222, and the downstream second portion223. The lower surface221aof the intermediate portion221is disposed at the height position lower than those of the lower surface211aof the upstream first portion211and the lower surface212aof the downstream first portion212. Further, the upper surface221bof the intermediate portion221is disposed at the height position higher than those of the upper surface211bof the upstream first portion211and the upper surface212bof the downstream first portion212. The opening1121of the branch path112is formed below the periphery of the intermediate portion221.

The upstream second portion222includes the lower surface222ainclined downward from the lower surface211aof the upstream first portion211toward the lower surface221aof the intermediate portion221, and the upper surface222binclined upward from the upper surface211bof the upstream first portion211toward the upper surface221bof the intermediate portion221. The downstream second portion223includes the lower surface223ainclined upward from the lower surface221aof the intermediate portion221toward the lower surface212aof the downstream first portion212, and the upper surface223binclined downward from the upper surface221bof the intermediate portion221toward the upper surface212bof the downstream first portion212.

As described above, by providing the second portion202having a larger sectional area than that the first portion201in the first pipeline104a3and forming the opening1121below the periphery of the second portion202, it is possible to suppress the foams from entering the opening1121. Further, the upstream second portion222, which is a connection portion between the upstream first portion211and the intermediate portion221, and the downstream second portion223, which is a connection portion between the intermediate portion221and the downstream first portion212, are tapered. Thus, the sectional area of the first pipeline104a3can be gradually changed between the first portion201and the second portion202. Therefore, it is possible to suppress turbulence in the flow of the processing liquid, for example, at the connection portion between the upstream first portion211and the intermediate portion221and at the connection portion between the intermediate portion221and the downstream first portion212.

Further, by tapering the upstream second portion222which is the connection portion between the upstream first portion211and the intermediate portion221, it is possible to suppress a flow separation.

Further, as illustrated inFIG.14, in a first pipeline104a4according to the third modification, the upstream first portion211and the downstream first portion212are disposed at the same height position.

The second portion202includes the intermediate portion221, the upstream second portion222, and the downstream second portion223. The lower surface221aof the intermediate portion221is disposed at the height positon lower than those of the lower surface211aof the upstream first portion211and the lower surface212aof the downstream first portion212. Further, the upper surface221bof the intermediate portion221is disposed at the same height position to those of the upper surface211bof the upstream first portion211and the upper surface212bof the downstream first portion212. The opening1121of the branch path112is formed below the periphery of the intermediate portion221.

The upstream second portion222includes the lower surface222ainclined downward from the lower surface211aof the upstream first portion211toward the lower surface221aof the intermediate portion221. The downstream second portion223includes the lower surface223ainclined upward from the lower surface221aof the intermediate portion221toward the lower surface212aof the downstream first portion212. The upper surface222bof the upstream second portion222and the upper surface223bof the downstream second portion223are disposed at the same height position to those of the upper surface211bof the upstream first portion211, the upper surface221bof the intermediate portion221, and the upper surface212bof the downstream first portion212.

As described above, by providing the second portion202having a larger sectional area than that of the first portion201in the first pipeline104a4and forming the opening1121below the periphery of the second portion202, it is possible to suppress the foams from entering the opening1121. Further, the upstream second portion222, which is a connection portion between the upstream first portion211and the intermediate portion221, and the downstream second portion223, which is a connection portion between the intermediate portion221and the downstream first portion212, are tapered. Thus, the sectional area of the first pipeline104a4can be gradually changed between the first portion201and the second portion202. Therefore, it is possible to suppress turbulence in the flow of the processing liquid, for example, at the connection portion between the upstream first portion211and the intermediate portion221and at the connection portion between the intermediate portion221and the downstream first portion212. Further, the upper surface211bof the upstream first portion211, the upper surface222bof the upstream second portion222, the upper surface221bof the intermediate portion221, the upper surface223bof the downstream second portion223, and the upper surface212bof the downstream first portion212are disposed at the same height position. Therefore, it is possible to suppress the foams from staying in the first pipeline104a4.

Each of the first pipelines104a1to104a4has a plurality of second portions202corresponding to a plurality of branching parts112a. In addition, an upstream first portion211provided in the upstream of one second portion202corresponds to a downstream first portion212provided in the downstream of another second portion202provided in the upstream of the one second portion202. Similarly, a downstream first portion212provided in the downstream of one second portion202corresponds to an upstream first portion211provided in the upstream of another second portion202provided in the downstream of the one second portion202. The upstream first portion211provided in the upstream of the second portion202provided in the most upstream side among the plurality of second portions202is connected to the defoamer301via a pipeline, which is provided in the upstream of each of the first pipelines104alto104a4in the circulation path104and through which the processing liquid passes downward. Further, the downstream first portion212provided in the downstream of the second portion202provided in the most downstream side among the plurality of second portions202is connected to the gas discharger302.

The modifications of the first embodiment can be also applied to the second embodiment. In other words, in the second embodiment, the position of the opening1121formed in each of the first pipelines104alto104a4is not limited to the directly-below position, but may be any lower position where relatively small foams do not enter, such as an oblique position. Further, the first pipelines104alto104a4are not limited to the horizontal direction, but may be inclined obliquely as long as the gas and the processing liquid can be separated from each other.

Further effects and modifications can be easily derived by those skilled in the art. Thus, the broader aspects of the present disclosure are not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications can be made without departing from the spirit or scope of the general inventive concepts as defined by the appended claims and equivalents thereof.

EXPLANATION OF REFERENCE NUMERALS