Processing liquid supply system and its operating method

Abstract

To achieve high cleanliness and discharge accuracy with the smaller number of components even when using a chemical solution with high viscosity.SOLUTION: A treatment liquid supply system according to an embodiment of the present disclosure, comprises: a tank that accumulates treatment liquid supplied from a treatment liquid supply part; a circulation passage connected to the tank; a plurality of supply passages that is connected to the circulation passage, and supplies each treatment liquid to a plurality of liquid treatment parts that performs a liquid treatment on a substrate; a set of first pump filters that is a combination of the first pump and a plurality of first filters provided on downstream side thereof; and a set of second pump filters that is a combination of the second pump and a plurality of second filters provided on downstream side thereof. The set of first pump filters and the set of second pump filters are arranged in series on the circulation passage so that the set of first pump filters is positioned on an upstream side of the set of second pump filters.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a processing liquid supply system and an operation method thereof.

Background Art

[0002] In the manufacturing process of semiconductor devices, a process of supplying a predetermined processing liquid to a workpiece such as a semiconductor wafer and performing liquid processing such as cleaning or wet etching is included. In a liquid processing apparatus having a plurality of liquid processing units for performing such liquid processing, an example of a processing liquid supply system for supplying a processing liquid to the liquid processing units is described in Patent Document 1. The processing liquid supply system described in Patent Document 1 has a tank for storing the processing liquid and a circulation passage with both ends connected to the tank. The circulation passage has a main passage portion provided with a pump, a first branch passage portion and a second branch passage portion branched from the main passage portion, and the processing liquid flowing out of the tank passes through the main passage portion and then flows into each branch passage portion and is configured to return to the tank through each branch passage portion. The plurality of liquid processing units are grouped into a first processing unit group and a second processing unit group. The plurality of supply passages are grouped into a first passage group and a second passage group, and the liquid processing units belonging to the first processing unit group are each connected to the first branch passage portion via a supply passage belonging to the first passage group, and the liquid processing units belonging to the second processing unit group are each connected to the second branch passage portion via a supply passage belonging to the second passage group.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present disclosure provides a processing liquid supply technology capable of achieving high cleanliness and discharge accuracy of the processing liquid with a small number of parts even when using a chemical liquid with high viscosity. [Means for solving the problem]

[0005] A processing liquid supply system according to one embodiment of the present disclosure includes a tank for storing processing liquid supplied from a processing liquid supply unit, a circulation passage connected to the tank, a plurality of supply passages connected to the circulation passage for supplying processing liquid to a plurality of liquid processing units that perform liquid processing on a substrate, a first pump filter set which is a combination of a first pump and a plurality of first filters provided downstream of it, and a second pump filter set which is a combination of a second pump and a plurality of second filters provided downstream of it, wherein the first pump filter set and the second pump filter set are arranged in series in the circulation passage such that the first pump filter set is located upstream of the second pump filter set. [Effects of the Invention]

[0006] According to the embodiments described above in this disclosure, high cleanliness and dispensing accuracy can be achieved with a small number of parts, even when using highly viscous chemical solutions. [Brief explanation of the drawing]

[0007] [Figure 1] This is a piping diagram of a liquid processing device equipped with a processing liquid supply system according to one embodiment. [Figure 2] This is a piping diagram illustrating the drainage system provided for multiple filters arranged in parallel. [Figure 3] This is a time chart illustrating the first example of the operation method (startup procedure) for the processing liquid supply system. [Figure 4] This is a time chart illustrating the second example of the operation method (startup procedure) for the processing liquid supply system. [Modes for carrying out the invention]

[0008] Embodiments of the liquid processing apparatus will be described with reference to the attached drawings. In each drawing, the same or generally identical components are given the same reference numerals.

[0009] Figure 1 is a piping diagram (fluid circuit diagram) of a liquid processing apparatus equipped with a processing liquid supply system 1 according to the first embodiment. The liquid processing apparatus has a plurality of liquid processing units 60 (60A, 60B) to which processing liquid is supplied by the processing liquid supply system 1.

[0010] The liquid processing unit 60 is, for example, a single-wafer rotary liquid processing unit. The rotary liquid processing unit has a substrate rotation and holding mechanism (called a spin chuck, etc.) that holds a substrate such as a semiconductor wafer in a horizontal position and rotates it around a vertical axis, and at least one nozzle that supplies processing liquid supplied from the processing liquid supply system 1 to the substrate held by the substrate rotation and holding mechanism. Since the configuration of such a rotary liquid processing unit is well known in the field of semiconductor manufacturing equipment, a detailed explanation will be omitted.

[0011] The processing liquid supply system 1 includes a tank 10 for storing processing liquid supplied from a processing liquid supply unit 70 that supplies raw material liquids (for example, one or more chemical solutions and diluents such as pure water) or pre-mixed processing liquids for mixing processing liquids, and a circulation passage 20 connected to the tank 10. The processing liquid supply unit 70 may include a tank (a tank separate from tank 10) for storing pre-mixed processing liquids. The processing liquid supply unit 70 may supply processing liquids that are mixtures of multiple components, or it may supply processing liquids that are single components.

[0012] The circulation passage 20 has an upstream main passage section (trunk pipe section) 22 and a plurality of (two in the illustrated example) downstream branch passage sections (branch pipe sections) 24A, 24B (hereinafter also referred to as "first branch passage section 24A" and "second branch passage section 24B").

[0013] It is not necessarily required to branch the circulation passage 20 into multiple branch passage sections; the main passage section 22 may extend directly to the tank 10.

[0014] In this specification, the reference numeral ending in "A" is used for components attached to the first branch passage section 24A, and the reference numeral ending in "B" is used for components attached to the second branch passage section 24B. The components attached to the first branch passage section 24A and the components attached to the second branch passage section 24B are either identical or substantially identical to each other. When there is no need to distinguish between the components attached to the first branch passage section 24A and the components attached to the second branch passage section 24B, the trailing letters "A" and "B" may be omitted (for example, 40A and 40B may be written as 40). Furthermore, components whose reference numeral ending in "A" may be referred to as "the first (of) (component name)," and components whose reference numeral ending in "B" may be referred to as "the second (of) (component name)." In addition, "the first (of)" and "the second (of)" may be omitted.

[0015] The main passage section 22 is provided with two sets of pump filter sets (meaning sets of pumps and filters), namely the first pump filter set 30 on the upstream side and the second pump filter set 40 on the downstream side. The first pump filter set 30 consists of a first pump 31 and a plurality of first filters 32 installed in parallel downstream of the first pump 31. The second pump filter set 40 consists of a second pump 41 and a plurality of second filters 42 installed in parallel downstream of the second pump 41. The filters (32, 42) remove contaminants such as particles contained in the processing liquid. A temperature sensor 21P is provided in the main passage section 22 between the first pump 31 and the plurality of first filters 32 of the first pump filter set 30.

[0016] In one preferred embodiment, the first pump 31 and the second pump 41 are rotary centrifugal pumps of the same specifications, such as magnetically levitated bearingless centrifugal pumps. Magnetically levitated bearingless centrifugal pumps are suitable for use in the processing liquid supply system of semiconductor manufacturing equipment because, despite being rotary pumps, they generate almost no pump-derived particles. Furthermore, connecting two rotary pumps in series is advantageous in constructing the processing liquid supply system 1 shown in Figure 1 because one pump will hardly adversely affect the other.

[0017] However, it is also possible to use pumps of a type other than those described above. For example, by arranging multiple reciprocating pumps (diaphragm pumps, bellows pumps, etc.) in parallel, it is possible to construct a single pump assembly in which pulsation is substantially eliminated. If pulsation is substantially eliminated, two such pump assemblies can be used instead of the first pump 31 and the second pump 41. If the first pump 31 and the second pump 41 are reciprocating pumps, it is possible to connect the first pump 31 and the second pump 41 in series by providing a buffer tank or accumulator between the first pump filter assembly 30 and the second pump filter assembly 40.

[0018] At a branching point (first branching point) 29 set between the first pump filter assembly 30 and the second pump filter assembly 40, a return passage 80 branches off from the main passage section 22 and extends to the tank 10. The return passage 80 is equipped with an on-off valve 81, a flow meter 82, and a back pressure valve 83, in that order from the upstream side.

[0019] The main passage section 22 branches into a first branch passage section 24A and a second branch passage section 24B at a branching point (second branching point) 23 located downstream of the second pump filter assembly 40, which is at its downstream end. The treated liquid discharged from the tank 10 passes through the main passage section 22, then flows into the first branch passage section 24A and the second branch passage section 24B, and returns to the tank 10 through the first branch passage section 24A and the second branch passage section 24B.

[0020] The liquid treatment units 60 are grouped into the same number (two in the illustrated example) of groups as the number of the branch passage portions (24A, 24B). The liquid treatment unit 60A belonging to the first group is supplied with the treatment liquid from the first branch passage portion 24A. For this reason, a plurality of supply passages 62 (62A) branch off in parallel from the first branch passage portion 24A and are connected to any one of the liquid treatment units 60A belonging to the first group. The liquid treatment unit 60B belonging to the second group is supplied with the treatment liquid from the second branch passage portion 24B. For this reason, a plurality of supply passages 62 (62B) branch off in parallel from the second branch passage portion 24B and are connected to any one of the liquid treatment units 60B belonging to the second group. The number of the liquid treatment units (60A, 60B) belonging to each group is the same as each other. In one embodiment, a plurality of liquid treatment units 60A belonging to the first group are arranged on the left side of a substrate transfer area (not shown) of the processing block of the liquid treatment apparatus, and a plurality of liquid treatment units 60B belonging to the second group are arranged on the right side of the transfer area.

[0021] For simplification of the drawing, FIG. 1 depicts an example in which three liquid treatment units 60 belong to one group, but the number of the treatment units belonging to one group is not limited to this. The number of the treatment units belonging to one group can be, for example, about 6 to 10.

[0022] Each supply passage 62 is provided with a flow control device 64 indicated by a symbol of a white rectangle. The flow control device 64 is configured by appropriately combining devices such as an on-off valve, a flow control valve, a flow meter, and a liquid flow controller. The downstream end of the supply passage 62 is connected to a nozzle (not shown) that supplies the treatment liquid to the substrate W. Therefore, it is possible to supply the treatment liquid from the nozzle to the substrate W loaded in the liquid treatment unit 60 at a controlled flow rate.

[0023] In the branch passage section 24A, the following components are provided in order from the upstream side: a temperature control unit 50 (50A), a temperature sensor 21Q (21QA), a flow meter 25 (25A), an on-off valve 26 (26A), an on-off valve 27 (27A), and a back pressure valve 28 (28A). Similarly, in the branch passage section 24B, the following components are provided in order from the upstream side: a temperature control unit 50 (50B), a temperature sensor 21Q (21QB), a flow meter 25 (25B), an on-off valve 26 (26B), an on-off valve 27 (27B), and a back pressure valve 28 (28B).

[0024] The back pressure valve 28 is provided to maintain a constant pressure of the processed liquid flowing through the region where multiple liquid processing sections 60 (60A, 60B) (supply passages 62 (62A, 62B)) of the branch passage sections 24A and 24B are connected. Any type of variable-opening valve can be used instead of the back pressure valve 28, as long as its opening degree can be controlled to perform this role.

[0025] The temperature control unit 50 (50A, 50B) adjusts the temperature of the processing liquid passing through it. The temperature control unit 50 may consist of a single temperature control module or of multiple temperature control modules arranged in parallel. The temperature control module may be a module that performs only heating, such as a resistance heater or a lamp heater, or it may be a heating / cooling module that is capable of both heating and cooling and is equipped with a temperature control element (e.g., a Peltier element). The number of temperature control modules belonging to one temperature control unit 50 can be determined by considering the required temperature control capacity of the temperature control unit 50 and the allowable pressure drop in the temperature control unit 50.

[0026] The liquid processing device has a control unit 100. The control unit 100 is, for example, a computer and has a control calculation unit 101 and a storage unit 102. The storage unit 102 stores a program that controls various processes performed in the liquid processing device. The control calculation unit 101 controls the operation of various components of the liquid processing device by reading and executing the program stored in the storage unit 102. The program may have been recorded on a storage medium readable by the computer and installed from that storage medium to the storage unit 102 of the control unit 100. Examples of storage mediums readable by the computer include hard disks (HDs), flexible disks (FDs), compact disks (CDs), magnetic optical disks (MOs), and memory cards.

[0027] The control unit 100 controls the temperature control operation (heating and / or cooling operation) of the temperature control unit 50A based on the temperatures detected by the temperature sensor 21P near the outlet of the pump 31, the temperature sensor 21QA near the outlet of the temperature control unit 50A, and the temperature sensor 21RA located just upstream of the connection area of ​​the supply passage 62A of the first branch passage section 24A, thereby maintaining the temperature of the processing liquid supplied from the first branch passage section 24A to the liquid processing section 60A at a target value.

[0028] Similarly, the control unit 100 controls the temperature control operation (heating and / or cooling operation) of the temperature control unit 50B based on the temperatures detected by the temperature sensor 21P near the outlet of the pump 31, the temperature sensor 21QB near the outlet of the temperature control unit 50B, and the temperature sensor 21RB located just upstream of the connection area of ​​the supply passage 62B of the second branch passage section 24B, thereby maintaining the temperature of the processing liquid supplied from the second branch passage section 24B to the liquid processing section 60B at a target value.

[0029] According to the above embodiment, the processing liquid sent out by the first pump 31 of the upstream first pump filter set 30 passes through the (multiple) first filters 32, causing a pressure drop. This pressure-reduced processing liquid is then pressurized by the second pump 41 of the downstream second pump filter set 40 and sent out, passing through the (multiple) second filters 42. In this way, the pressure is repeatedly increased by the pump and decreased by the filter. By arranging multiple sets (two sets in the illustrated example) of pump filter sets 30 and 40 in series, the processing liquid can be flowed through the circulation passage 20 at a precisely controlled desired flow rate, even when the viscosity of the processing liquid is high. Furthermore, when performing multi-stage filtration, it is possible to operate with ample margin in terms of the differential pressure tolerance of each filter. In addition, since multi-stage filtration can be performed without problems, the cleanliness of the processing liquid can be increased.

[0030] Increasing the number of parallel-arranged filters belonging to a single pump-filter system can increase the flow rate of the treated liquid that passes through that single pump-filter system.

[0031] The number of pump filter sets (30,40) is not limited to 2; it can be 3 or more.

[0032] Another pump or another pump filter set may be provided downstream of the most downstream pump filter set (30, 40).

[0033] Next, the operating method of the liquid treatment apparatus's treatment liquid supply system 1 (in particular, the procedure for starting up the treatment liquid supply system 1 from a stopped state) will be described.

[0034] First, the initial startup procedure will be explained with reference to the time chart in Figure 2. In the time chart in Figure 2, from top to bottom, the rotational speed of the first pump 31 (0, low rotational speed L, or high rotational speed H), the rotational speed of the second pump 41 (0, low rotational speed L, or high rotational speed H), the state of the on-off valve 81 (open or closed), the control state of the back pressure valve 83 (fully open (WO) or primary side pressure control (CTRL)), and the state of the on-off valve 26A (open or closed (CLOS)). E)) shows the state of the on / off valve 26B (open or closed), the state of the temperature control unit 50A (energized or not energized), the state of the temperature control unit 50B (energized or not energized), the control state of the back pressure valve 28A (fully open (WO) or primary side pressure control (CTRL)), and the control state of the back pressure valve 28B (fully open (WO) or primary side pressure control (CTRL)).

[0035] At a point slightly before time t1 in Figure 2, the excitation of the first pump 31 and the second pump 41 is started. Subsequently, the excitation of the first pump 31 and the second pump 41 continues until the processing liquid supply system 1 is completely stopped. The excitation causes the rotor (vanes) of the magnetically levitated bearingless centrifugal pump to levitate, putting the rotor into a standby state where it can start rotating at any time.

[0036] At time t1, the back pressure valve 28A of the first branch passage section 24A is opened (WO), and the on-off valves 26A and 27A are opened (OPEN). The back pressure valve 83 of the return passage 80 is opened (WO), and the on-off valve 81 is opened (OPEN). The on-off valves 26B and 27B of the second branch passage section 24B are kept closed (CLOSE). In this state, the operation (rotation) of the first pump 31 is started. The first pump 31 is initially rotated at an initial rotational speed (for example, a low rotational speed (L) of about 2000 rpm) to discharge the processed liquid at a relatively small flow rate. After that, the rotational speed of the first pump 31 is increased to the normal operating speed (for example, a high rotational speed (H) of about 7000 to 8000 rpm) to discharge the processed liquid from the first pump 31 at a relatively large flow rate.

[0037] The initial rotational speed mentioned above is, for example, the minimum rotational speed required to draw liquid into the first pump 31. Since it takes some time for the first pump 31 to increase in speed from the initial rotational speed to the normal operating speed due to liquid resistance, the line showing the pump's rotational speed during the speed-increasing process is sloped.

[0038] By performing the above procedure, a circulating flow of the processed liquid is formed, which starts from tank 10 and flows through a sub-circulation path that returns to tank 10 via the first pump filter assembly 30 and the return passage 80. This circulating flow is continuously present during the operation of the processed liquid supply system 1. The presence of this circulating flow increases the flow rate of the processed liquid per unit time passing through the first filter 32, thereby improving the cleanliness of the processed liquid. At this time, since the second pump 41 is not yet rotating, little to no processed liquid flows out to the downstream side of the second pump filter assembly 40.

[0039] Next, at time t2, the operation (rotation) of the second pump 41 is started, and the back pressure valve 83 is switched from the fully open state (WO) to the primary side pressure control state (CTRL), so that the flow rate of the processed liquid flowing through the return passage 80 is controlled to a predetermined flow rate lower than when it is fully open. Accordingly, the primary side pressure of the second pump 41 is also maintained at a predetermined pressure. The primary side setting pressure of the back pressure valve 83 at this time should be determined considering the filtration efficiency of the first filter 32.

[0040] The fully open state (WO) of the back pressure valve 83 means that the opening degree of the back pressure valve 83 is fixed to fully open regardless of the primary side pressure of the back pressure valve 83, and the primary side pressure control state (CTRL) means that the back pressure valve 83 is performing its function as a back pressure valve by controlling its primary side pressure to a predetermined pressure. The same applies to the other back pressure valves 28A and 28B. In the fully open state (WO), the opening degree of the back pressure valve 83 is not limited to being completely fully open, but may be a large opening degree close to fully open. In controlling the back pressure valve 83, an opening degree larger than the maximum opening degree that the back pressure valve 83 can take in the primary side pressure control state (CTRL) may be used instead of the fully open opening degree. The same applies to the other back pressure valves 28A and 28B.

[0041] The second pump 41 is initially rotated at an initial rotational speed (for example, a low rotational speed of about 2000 rpm (L)) to discharge the processed liquid at a relatively small flow rate, and this state is continued for about 30 seconds. After that, the rotational speed of the second pump 41 is increased to the normal operating speed (for example, a high rotational speed of about 7000-8000 rpm (H)) to discharge the processed liquid at a relatively large flow rate. The increase in rotational speed from the initial rotational speed to the normal operating speed is carried out over a period of about 10 minutes, for example.

[0042] When the first pump 31 and the second pump 41 are operating (rotating) simultaneously, the rotational speed (discharge flow rate) of the first pump 31 should be the same as or slightly higher than the rotational speed (discharge flow rate) of the second pump 41 (slightly higher is preferable). If the rotational speed (discharge flow rate) of the first pump 31 is lower than that of the second pump 41, there is a risk that the liquid supply to the primary side (suction side) of the second pump 41 will be interrupted.

[0043] By performing the above procedure, the processing liquid, driven by the second pump 41, flows into the first branch passage section 24A after passing through the second filter 42. In other words, a circulating flow of processing liquid is formed that starts from the tank 10, passes through the main passage section 22 and the first branch passage section 24A of the circulation passage 20, and returns to the tank 10. The flow rate of this circulating flow increases as the rotational speed of the second pump 41 increases.

[0044] Next, at time t3 (after the second pump 41 has stabilized at its normal operating speed), the on-off valves 26A and 27A of the first branch passage section 24A are closed (CLOSE), and the back pressure valve 28B of the second branch passage section 24B is fully opened (WO), opening the on-off valves 26B and 27B (OPEN). This creates a circulating flow of the processed liquid that starts from the tank 10, passes through the main passage section 22 and the second branch passage section 24B of the circulation passage 20, and returns to the tank 10. At this time, the second branch passage section 24B is filled with processed liquid, but the flow stops.

[0045] Next, at time t4, the on-off valves 26A and 27A of the first branch passage section 24A are opened. This creates a flow of processed liquid that passes through the main passage section 22 of the circulation passage 20 and then returns to the tank 10 through both the first branch passage section 24A and the second branch passage section 24B. At this time, the flow of processed liquid is distributed to the first branch passage section 24A and the second branch passage section 24B, so the flow rate of processed liquid passing through each of the first branch passage section 24A and the second branch passage section 24B decreases.

[0046] At this point, the processing liquid that has left tank 10 is driven by the first pump 31 to pass through the first filter 32, and a portion of the processing liquid that has passed through the first filter 32 is returned to tank 10 through the return passage 80. Meanwhile, the remaining portion of the processing liquid that has passed through the first filter 32 is driven by the second pump 41 to pass through the second filter 42, and after passing through the first branch passage section 24A and the second branch passage section 24B, it is returned to tank 10.

[0047] Next, at time t5, once the flow of the processing liquid in the second branch passage section 24B has stabilized, the temperature control unit 50B starts controlling the temperature of the processing liquid (ON). Furthermore, at time t6, once the flow of the processing liquid in the first branch passage section 24A has stabilized, the temperature control unit 50A starts controlling the temperature of the processing liquid (ON). The temperature control units 50A and 50B may start controlling the temperature of the processing liquid simultaneously.

[0048] Next, at time t7, once the temperature of the processing liquid in the second branch passage section 24B has stabilized, the back pressure valve 28B of the second branch passage section 24B is switched from the fully open state (WO) to the primary side pressure control state (CTRL). Furthermore, at time t8, once the temperature of the processing liquid in the first branch passage section 24A has stabilized, the back pressure valve 28A of the first branch passage section 24A is switched from the fully open state (WO) to the primary side pressure control state (CTRL). As a result, the pressure in the portion of the first branch passage section 24A and the second branch passage section 24B connected to the supply passage 62 (62A, 62B) connected to the liquid processing section 60 (60A, 60B) is controlled to a pressure suitable for supplying processing liquid to the liquid processing section 60. Consequently, the flow rate of the processing liquid flowing through the first branch passage section 24A and the second branch passage section 24B decreases slightly. The transition of the back pressure valves 28A and 28B to the primary side pressure control state may be performed simultaneously.

[0049] Once the flow rate of the processing liquid in the first branch passage section 24A and the second branch passage section 24B stabilizes, the liquid processing section 60 (60A, 60B) becomes ready to perform processing. This completes the series of startup procedures for the processing liquid supply system 1. Time points t7 and t8 may be the same time.

[0050] Subsequently, the substrate is treated with liquid in the liquid treatment unit 60 according to a predetermined processing schedule.

[0051] Next, the second startup procedure will be explained with reference to the time chart in Figure 3. In the time chart in Figure 3, the intermediate rotational speed M is added to the rotational speed of pumps 31 and 41.

[0052] At a time slightly before time t11 in Figure 3, the excitation of the first pump 31 and the second pump 41 is started. The excitation causes the first pump 31 and the second pump 41 to enter a rotational standby state.

[0053] Furthermore, at time t11, the back pressure valve 28A of the first branch passage section 24A is opened (WO), and the on-off valves 26A and 27A are opened (OPEN), and the back pressure valve 83 of the return passage 80 is opened (WO), and the on-off valve 81 is opened. The on-off valves 26B and 27B of the second branch passage section 24B are kept closed (CLOSE). In this state, the operation (rotation) of the first pump 31 is started. The first pump 31 is initially rotated at an initial rotational speed (for example, a low rotational speed (L) of about 2000 rpm) to discharge the processed liquid at a relatively small flow rate. After that, the first pump 31 is increased in speed to an intermediate rotational speed (M) (for example, about 6400 rpm) which is lower than the normal operating rotational speed (for example, a high rotational speed (H) of about 7000 to 8000 rpm), so that the processed liquid is discharged at a moderate discharge flow rate.

[0054] This creates a circulating flow (sub-circulating flow) of the processed liquid that starts from tank 10 and flows through the first pump filter assembly 30 and the return passage 80 (first return passage 80) back to tank 10.

[0055] Next, at time t12, the operation (rotation) of the second pump 41 is started, and the back pressure valve 83 is switched to the primary side pressure control state. This controls the pressure in the return passage 80 to a predetermined pressure, and also controls the primary side pressure of the second pump 41 to a predetermined pressure. The second pump 41 is also initially rotated at an initial rotational speed (for example, a low rotational speed (L) of about 2000 rpm) to discharge the processed liquid at a relatively small flow rate. After that, the rotational speed of the second pump 41 is increased to an intermediate rotational speed (M) (for example, about 6400 rpm) which is lower than the normal operating rotational speed (for example, a high rotational speed (H) of about 7000 to 8000 rpm), so that the processed liquid is discharged at a moderate discharge flow rate.

[0056] In this second procedure, as in the first procedure, when the first pump 31 and the second pump 41 are operating simultaneously, the rotational speed (discharge flow rate) of the first pump 31 is set to be equal to or greater than the rotational speed (discharge flow rate) of the second pump 41.

[0057] As a result, the processing liquid, driven by the second pump 41, flows into the first branch passage section 24A after passing through the second filter 42. In other words, a circulating flow of processing liquid is formed that starts from the tank 10, passes through the main passage section 22 and the first branch passage section 24A of the circulation passage 20, and returns to the tank 10. The flow rate of this circulating flow increases as the rotational speed of the second pump 41 increases.

[0058] Next, at time t13, the back pressure valve 28B of the second branch passage section 24B is opened (WO), and the on / off valves 26B and 27B are opened (OPEN). As a result, the processed liquid flows from the main passage section 22 of the circulation passage 20 into both the first branch passage section 24A and the second branch passage section 24B, and flows toward the tank 10.

[0059] Next, at time t14, the on-off valves 26A and 27A of the first branch passage section 24A are closed. As a result, while the processing liquid flows into the second branch passage section 24B, the first branch passage section 24A is filled with the processing liquid and the flow stops. The time between time t13 and time t14 can be short. It is sufficient to eliminate the possibility of a moment when on-off valves 26A and 26B are closed simultaneously.

[0060] Next, at time t15, the on-off valves 26A and 27A of the first branch passage section 24A are opened. As a result, the processed liquid flows again from the main passage section 22 of the circulation passage 20 into both the first branch passage section 24A and the second branch passage section 24B, and flows towards the tank 10.

[0061] In other words, at this point, the processed liquid that has left tank 10 is driven by the first pump 31 to pass through the first filter 32, and a portion of the processed liquid that has passed through the first filter 32 is returned to tank 10 through the return passage 80. Meanwhile, the remaining portion of the processed liquid that has passed through the first filter 32 is driven by the second pump 41 to pass through the second filter 42, and after passing through the first branch passage section 24A and the second branch passage section 24B, it is returned to tank 10.

[0062] The advantages of the procedure at time points t13 to t15 will be explained. In the first startup procedure described above, the opening of valves 26B and 27B and the closing of valves 26A and 27A occur almost simultaneously. In this case, especially when the viscosity of the processing liquid is low, a water hammer phenomenon may occur, which may result in damage to the upstream component of valve 26A. Furthermore, if the closing of valve 26A precedes the opening of valve 26B, the impact pressure caused by the water hammer phenomenon becomes more pronounced. For example, if the temperature control unit 50A consists of a lamp heater using a quartz tube, the heater may be damaged.

[0063] In contrast, in the second startup procedure, the opening of valves 26B and 27B (time t13) precedes the closing of valves 26A and 27A (time t14). In other words, by the time valve 26A is closed, the flow rate (pressure) of the processing liquid flowing through the first branch passage section 24A has decreased significantly compared to before. Therefore, even if the water hammer phenomenon described above occurs, the resulting equipment damage is greatly suppressed.

[0064] Furthermore, in the second startup procedure, the rotational speeds of the first pump 31 and the second pump 41 when the on-off valves 26B and 27B are opened and the on-off valves 26A and 27A are closed are lower than the rotational speeds of the first pump 31 and the second pump 41 when performing similar operations in the first startup procedure. Therefore, even if the water hammer phenomenon described above occurs, the resulting equipment damage is significantly suppressed.

[0065] Furthermore, at time t15, along with the opening of the on-off valves 26A and 27A, the rotational speeds of the first pump 31 and the second pump 41 are increased from an intermediate rotational speed (M) (for example, around 6400 rpm) to a normal operating rotational speed (for example, a high rotational speed (H) of around 7000-8000 rpm), so that the processed liquid is discharged from the first pump 31 and the second pump 41 at a relatively large flow rate.

[0066] Next, at time t16, once the flow of the processing liquid in the first branch passage section 24A and the second branch passage section 24B has stabilized to a certain extent, the temperature control units 50A and 50B start controlling the temperature of the processing liquid (ON).

[0067] Next, at time t17, once the temperature of the processing liquid in the first branch passage section 24A and the second branch passage section 24B has stabilized, the back pressure valve 28A of the first branch passage section 24A and the back pressure valve 28B of the second branch passage section 24B are switched to the primary side pressure control state (CTRL). As a result, the pressure in the portion of the first branch passage section 24A and the second branch passage section 24B connected to the supply passage 62 (62A, 62B) connected to the liquid processing section 60 (60A, 60B) is controlled to a pressure suitable for supplying processing liquid to the liquid processing section 60. Consequently, the flow rate of the processing liquid flowing through the first branch passage section 24A and the second branch passage section 24B decreases slightly.

[0068] The transition of back pressure valves 28A and 28B from the fully open state (WO) to the primary pressure control state (CTRL) is performed gradually, for example, over a period of about 30 seconds. To achieve this gradual transition, it is preferable to use a back pressure valve that can receive an external primary pressure setting command, or a back pressure valve that can receive an external opening command independently of the primary pressure control. When using a back pressure valve that can receive an external primary pressure setting command, for example, the transition from the fully open state to the primary pressure control state can be made gradual by gradually increasing the primary pressure setting value of the back pressure valve so that it approaches the final pressure setting value.

[0069] The back pressure valves used in this disclosure are not structurally limited, as long as they can control the primary pressure to a desired pressure. For example, a variable-opening valve that controls the primary pressure to a desired pressure by feedback control of the opening degree based on a detection signal from a pressure sensor that detects the primary pressure also falls under the category of a back pressure valve in this disclosure. Furthermore, for example, a valve that mechanically controls the primary pressure according to the air pressure supplied to a pilot port by an electro-pneumatic regulator also falls under the category of a back pressure valve in this disclosure.

[0070] If the back pressure valves 28A and 28B are abruptly switched from the fully open state (WO) to the primary side pressure control state (CTRL), the pressure in the first branch passage section 24A and the second branch passage section 24B will increase rapidly. This rapid pressure increase, like the water hammer phenomenon described above, may damage components located upstream of the back pressure valves 28A and 28B, and therefore should be avoided.

[0071] Once the flow rate of the processing liquid in the first branch passage section 24A and the second branch passage section 24B stabilizes, the liquid processing section 60 (60A, 60B) becomes ready to perform processing. This completes the series of startup procedures for the processing liquid supply system 1.

[0072] Subsequently, the substrate is treated with liquid in the liquid treatment unit 60 according to a predetermined processing schedule.

[0073] In the two startup procedures described above, the second pump 41 is started after the first pump 31 reaches its normal operating speed, but this is not the only option. For example, the second pump 41 may be started after a predetermined delay time has elapsed following the start of the first pump 31. In this case, for example, the second pump 41 may be started around the time when the first pump 31 finishes operating at its initial speed and transitions to acceleration, and then the acceleration of the second pump 41 may be started after a delay of the predetermined delay time compared to the start of acceleration of the first pump 31. In this case, for example, the processing liquid will begin to flow into the first branch passage section 24A while the first pump 41 and the second pump 42 are simultaneously accelerating, but this does not pose a problem.

[0074] The processing liquid supply system 1 may be provided with a second return passage 80', as shown by the dashed line in Figure 1. This second return passage 80' may also be equipped with an on / off valve, a flow meter, and a back pressure valve, in order from the upstream side. By returning the processing liquid to the tank 10 via the second return passage 80', the flow rate of the processing liquid passing through the second filter 42 per unit time can be increased, thereby further improving the cleanliness of the processing liquid. It should be noted that the processing liquid supply system 1 can operate normally even without the first return passage 80 and the second return passage 80', so the processing liquid supply system 1 does not necessarily need to be equipped with the first return passage 80 and the second return passage 80'.

[0075] Next, referring to Figure 4, the drain piping associated with the multiple (six in Figure 4) first filters 32 arranged in parallel will be described. Each filter 32 is provided with, in detail, a primary main port M1, a secondary main port M2, a primary drain port D1, a secondary drain port D2, and a gas venting port G. The multiple first filters 32 shown in Figure 4 are connected in parallel as shown in Figure 1, where only the primary main port M1 and the secondary main port M2 are visible.

[0076] A primary side branch drain line 91i is connected to the primary side drain port D1 of each filter 32. Multiple primary side branch drain lines 91i merge to form a primary side main drain line 91. The primary side main drain line 91 extends to the tank 10. At connection point 91b, located slightly downstream of connection point 91a with the primary side branch drain line 91i at the downstream end of the primary side main drain line 91, a drain line 93 is connected to the primary side main drain line 91. An on / off valve 94 is provided in the drain line 93. Downstream of connection point 91b, an orifice ORF is provided in the primary side main drain line 91.

[0077] A secondary branch drain line 92i is connected to the secondary drain port D2 of each filter 32. Multiple secondary branch drain lines 92i merge to form a secondary main drain line 92. The secondary main drain line 92 extends to the tank 10. At connection point 92b, located slightly downstream of connection point 92a with the secondary branch drain line 92i at the downstream end of the secondary main drain line 92, a drain line 95 is connected to the secondary main drain line 92. An on-off valve 96 is provided in the drain line 95. Downstream of connection point 92b, an orifice ORF is provided in the secondary main drain line 92.

[0078] A gas venting branch line 97i is connected to the gas venting port G of each filter 32. Multiple gas venting branch lines 97i merge to form a gas venting main line 97. The gas venting main line 97 extends to the tank 10. An orifice ORF is provided in each gas venting branch line 97i.

[0079] During normal operation of the processing liquid supply system 1, when processing liquid flows from the primary main port M1 to the secondary main port M2 of each filter 32, a small amount of processing liquid is discharged from the primary drain port D1 and the secondary drain port D2. In addition, air bubbles contained in the processing liquid that flowed in from the primary main port M1 are discharged from the gas venting port G along with a small amount of processing liquid.

[0080] In the configuration example shown in Figure 4, the on-off valves 94 and 96 are closed during normal operation of the processing liquid supply system 1. Therefore, the liquid discharged from the primary drain port D1 and secondary drain port D2 of each filter 32 flows to the tank 10 without any stagnation along the way. The only dead volumes in this drainage system are the section between the connection point 91b of the drainage line 93 and the on-off valve 94, and the section between the connection point 92b of the drainage line 95 and the on-off valve 96. Thus, in the configuration example shown in Figure 4, there are no other areas where liquid stagnates besides the dead volumes mentioned above. When the liquid in the tank 10 is changed, the on-off valves 94 and 96 are opened, and the liquid stagnates in the dead volumes is also discharged.

[0081] The advantages of the configuration example shown in Figure 4 will be explained in comparison with a conventional configuration example. In a conventional configuration example, a drain line with an on / off valve is connected to each of the primary drain port (D1) and secondary drain port (D2) of each filter (32). In a processing liquid supply system with such a configuration, the liquid discharged from the primary drain port D1 and secondary drain port D2 during normal operation remains in the drain line. Particles contained in the liquid also accumulate in the drain line. There is a risk that the liquid containing particles will be drawn into the filter through the drain line and mixed into the processing liquid passing through the filter.

[0082] According to the configuration example in Figure 4, such problems rarely occur. This is because the liquid discharged from the primary drain port D1 and the secondary drain port D2 is returned to the tank 10 and then properly passes through the filtration element of the filter 32. There are no other areas where liquid accumulates besides the aforementioned dead volume, the total volume of the dead volume is small, and there is almost no possibility of the accumulated liquid returning to the filter 32. Furthermore, according to the configuration example in Figure 4, the number of on-off valves can be significantly reduced, which can also reduce the equipment cost.

[0083] The configuration example in Figure 4 can also be applied to multiple second filters 42.

[0084] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The above embodiments may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the appended claims.

[0085] The substrate is not limited to semiconductor wafers, but may also be other types of substrates used in the manufacture of semiconductor devices, such as glass substrates or ceramic substrates. [Explanation of Symbols]

[0086] 1. Processing liquid supply system 10 tanks 20 Circulation passage 60 Liquid treatment 62 Supply passage 30. First pump filter assembly 31 Pump No. 1 32 First Filter 40. Second pump filter assembly 41. Pump No. 2 42. Second filter 70 Processing liquid supply unit

Claims

1. A tank for storing the processing liquid supplied from the processing liquid supply unit, A circulation passage connected to the aforementioned tank, Multiple supply passages connected to the aforementioned circulation passage, each supplying processing liquid to multiple liquid processing units that perform liquid processing on the substrate, A first pump filter set is a combination of a first pump and a plurality of first filters installed downstream of it, A second pump filter set, which is a combination of a second pump and a plurality of second filters installed downstream of it, Equipped with, A processing liquid supply system in which the first pump filter set and the second pump filter set are arranged in series in the circulation passage such that the first pump filter set is located upstream of the second pump filter set.

2. The processing liquid supply system according to claim 1, further comprising a first return passage that branches off from the circulation passage at a first branching point set between the first pump filter set and the second pump filter set, and returns the processing liquid flowing through the circulation passage to the tank.

3. The processing liquid supply system according to claim 1 or 2, wherein the circulation passage has a main passage portion provided with the first pump filter set and the second pump filter set, and a first branch passage portion and a second branch passage portion branching off from the main passage portion, and the processing liquid discharged from the tank passes through the main passage portion, flows into the first branch passage portion and the second branch passage portion, and returns to the tank through the first branch passage portion and the second branch passage portion.

4. A processing liquid supply system according to claim 3, which is dependent on claim 2, further comprising a second return passage that branches off from the circulation passage and returns the processing liquid flowing through the main passage to the tank, located downstream of the second pump filter assembly and upstream of the branching point where the main passage branches off to the first branch passage and the second branch passage.

5. The processing liquid supply system according to claim 3, further comprising: a first temperature control unit provided in the first branch passage portion for controlling the temperature of the processing liquid flowing through the first branch passage portion; and a second temperature control unit provided in the second branch passage portion for controlling the temperature of the processing liquid flowing through the second branch passage portion.

6. The plurality of liquid processing units are grouped into a first processing unit group to which the plurality of liquid processing units belong and a second processing unit group to which the plurality of liquid processing units belong, and the plurality of supply passages are grouped into a first passage group to which the plurality of supply passages belong and a second passage group to which the plurality of supply passages belong, The processing liquid supply system according to claim 3, wherein each liquid processing unit belonging to the first processing unit group is connected to the first branching passage portion via a supply passage belonging to the first passage group, and each liquid processing unit belonging to the second processing unit group is connected to the second branching passage portion via a supply passage belonging to the second passage group.

7. It further includes a control unit, The processing liquid supply system according to claim 2, wherein the control unit operates the first pump when the processing liquid supply system starts operating to form a first circulating flow of processing liquid that returns from the tank to the tank through the circulation passage, the first branching point, and the first return passage, and thereafter operates the second pump while forming the first circulating flow to allow processing liquid to flow to the circulation passage downstream of the first branching point.

8. The system further comprises a control unit and a back pressure valve provided in the first return passage, The processing liquid supply system according to claim 2, wherein the control unit operates the first pump with the back pressure valve opening to a fixed degree when the processing liquid supply system starts operating, to form a first circulating flow of processing liquid that returns to the tank from the tank through the circulation passage, the first branching point and the first return passage, and thereafter operates the second pump with the back pressure valve in a pressure control state in which the primary side pressure of the back pressure valve is controlled to a desired pressure, and the fixed degree is the full opening of the back pressure valve, or at least a larger opening than the opening of the back pressure valve in the pressure control state.

9. The system further comprises a first on-off valve provided in the first branch passage portion, a second on-off valve provided in the second branch passage portion, and a control unit. The processing liquid supply system according to claim 3, wherein the control unit, when the processing liquid supply system starts operation, opens the first on-off valve and closes the second on-off valve, starts operation of the first pump at a first set flow rate, then starts operation of the second pump at a second set flow rate less than or equal to the first set flow rate, thereby flowing the processing liquid to the first branch passage, then operates the first pump at a first set flow rate and the second pump at a second set flow rate, closes the first on-off valve and opens the second on-off valve, thereby flowing the processing liquid to the second branch passage, and then opens both the first on-off valve and the second on-off valve, thereby flowing the processing liquid to both the first branch passage and the second branch passage.

10. The processing liquid supply system according to claim 9, wherein, with both the first on-off valve and the second on-off valve in an open state and processing liquid flowing through both the first branch passage portion and the second branch passage portion, the set flow rate of the first pump is increased to a third set flow rate which is greater than the first set flow rate, and the set flow rate of the second pump is increased to a fourth set flow rate which is greater than the second set flow rate and less than or equal to the third set flow rate.

11. The processing liquid supply system according to claim 9, wherein the control unit operates the first pump at a first set flow rate and the second pump at a second set flow rate, and when transitioning from a state in which the first on-off valve is closed and the second on-off valve is open to a state in which the first on-off valve is open and the second on-off valve is open, the control unit opens the second on-off valve before closing the first on-off valve.

12. A method for operating a processing liquid supply system, wherein the processing liquid supply system is A tank for storing the processing liquid supplied from the processing liquid supply unit, A circulation passage connected to the aforementioned tank, Multiple supply passages connected to the aforementioned circulation passage, each supplying processing liquid to multiple liquid processing units that perform liquid processing on the substrate, A first pump filter set is a combination of a first pump and a plurality of first filters installed downstream of it, A second pump filter set, which is a combination of a second pump and a plurality of second filters installed downstream of it, Equipped with, The first pump filter set and the second pump filter set are arranged in series in the circulation passage such that the first pump filter set is located upstream of the second pump filter set. The processing liquid supply system further includes a first return passage that branches off from the circulation passage at a first branching point set between the first pump filter set and the second pump filter set, and returns the processing liquid flowing through the circulation passage to the tank. The above operating method is an operating method in which, when the processing liquid supply system starts operating, the first pump is operated to form a first circulating flow of processing liquid that returns from the tank to the tank through the circulation passage, the first branching point and the first return passage, and thereafter, while forming the first circulating flow, the second pump is operated to allow the processing liquid to flow into the circulation passage downstream of the first branching point.

13. The processing liquid supply system further comprises a back pressure valve provided in the first return passage, The operating method according to claim 12, wherein, at the start of operation of the processing liquid supply system, the first pump is operated with the back pressure valve opening to a fixed degree to form a first circulating flow of processing liquid that returns to the tank from the tank through the circulation passage, the first branching point and the first return passage, and thereafter, the second pump is operated with the back pressure valve in a pressure control state in which the primary side pressure of the back pressure valve is controlled to a desired pressure, and the fixed degree is the full opening of the back pressure valve, or at least a larger opening than the opening of the back pressure valve in the pressure control state.

14. A method for operating a processing liquid supply system, wherein the processing liquid supply system is A tank for storing the processing liquid supplied from the processing liquid supply unit, A circulation passage connected to the aforementioned tank, Multiple supply passages connected to the aforementioned circulation passage, each supplying processing liquid to multiple liquid processing units that perform liquid processing on the substrate, A first pump filter set is a combination of a first pump and a plurality of first filters installed downstream of it, A second pump filter set, which is a combination of a second pump and a plurality of second filters installed downstream of it, Equipped with, The first pump filter set and the second pump filter set are arranged in series in the circulation passage such that the first pump filter set is located upstream of the second pump filter set. The circulation passage has a main passage portion where the first pump filter set and the second pump filter set are provided, and a first branch passage portion and a second branch passage portion branching off from the main passage portion. The treated liquid flowing out of the tank passes through the main passage portion, then flows into the first branch passage portion and the second branch passage portion, and is configured to return to the tank through the first branch passage portion and the second branch passage portion. The processing liquid supply system further comprises a first on-off valve provided in the first branch passage portion and a second on-off valve provided in the second branch passage portion. The above operating method is as follows: When the processing liquid supply system starts operating, the first on-off valve is opened and the second on-off valve is closed, and the first pump is started to operate at a first set flow rate; then the second pump is started to operate at a second set flow rate less than or equal to the first set flow rate, thereby flowing the processing liquid to the first branch passage; then, with the first pump operating at a first set flow rate and the second pump operating at a second set flow rate, the first on-off valve is closed and the second on-off valve is opened, thereby flowing the processing liquid to the second branch passage; and then, with both the first on-off valve and the second on-off valve open, the processing liquid flows to both the first branch passage and the second branch passage.

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