Substrate processing apparatus and processing liquid replenishment method

Abstract

To prevent a tank from being replenished with a processing liquid containing contaminants such as particles.SOLUTION: A substrate processing apparatus includes: a processing unit configured to perform a liquid processing on a substrate using a processing liquid; a tank configured to store the processing liquid before being supplied to the processing unit; a replenishment line configured to supply the processing liquid from a processing liquid supply source to the tank; a replenishment opening / closing valve configured to open and close the replenishment line; a first drain line branched from the replenishment line on an upstream side of the replenishment opening / closing valve; a first drain opening / closing valve configured to open and close the first drain line; and a control part. The control part controls an operation of the replenishment opening / closing valve and the first drain opening / closing valve to perform a preliminary disposal operation of draining the processing liquid flowing from the processing liquid supply source into the replenishment line through the first drain line before the replenishment of the processing liquid from the processing liquid supply source to the tank through the replenishment line is started.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a substrate processing apparatus and a processing liquid replenishment method. [Background technology]

[0002] The manufacturing process of semiconductor devices includes a liquid processing step in which a chemical liquid (processing liquid) is supplied to a substrate to perform chemical cleaning or wet etching. In a substrate processing system that performs such a liquid processing step, a processing liquid supply system that supplies processing liquid to multiple liquid processing units has a tank that stores the processing liquid and a circulation line that is connected to the tank at both ends and through which the processing liquid circulates. The processing liquid is supplied to the multiple liquid processing units via multiple branch lines that are connected to the circulation line. When the processing liquid in the tank decreases due to repeated substrate processing, the tank is replenished with new processing liquid. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-175552 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique for preventing a tank from being replenished with a processing liquid containing contaminants such as particles. [Means for solving the problem]

[0005] According to one embodiment of the present disclosure, there is provided a substrate processing apparatus comprising: a processing unit that performs liquid processing on a substrate using a processing liquid; a tank that stores the processing liquid before it is supplied to the processing unit; a replenishment line that supplies the processing liquid from a processing liquid supply source to the tank; a replenishment valve that opens and closes the replenishment line; a first drainage line that branches off from the replenishment line upstream of the replenishment valve; a first drainage valve that opens and closes the first drainage line; and a control unit, wherein the control unit controls the operation of the replenishment valve and the first drainage valve to perform a preliminary disposal operation in which the processing liquid flowing from the processing liquid supply source into the replenishment line is drained through the first drainage line before replenishment of the processing liquid from the processing liquid supply source through the replenishment line is started to the tank. [Effects of the Invention]

[0006] According to the above embodiment, it is possible to prevent the tank from being replenished with processing liquid containing contaminants such as particles. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic cross-sectional view of a substrate processing system according to an embodiment of the substrate processing apparatus. [Figure 2] FIG. 1 is a piping diagram showing an example of a configuration of a sulfuric acid supply mechanism among the processing liquid supply mechanisms included in the substrate processing system, and is a piping diagram showing a first embodiment of a sulfuric acid replenishment mechanism included in the sulfuric acid supply mechanism. [Figure 3] 10 is a flowchart illustrating an example of a flow related to a spare discard operation. [Figure 4] 10 is a flowchart showing another example of the flow related to the spare discard operation. [Figure 5] FIG. 10 is a piping diagram showing a second embodiment of a sulfuric acid replenishment mechanism. [Figure 6] FIG. 10 is a piping diagram showing a third embodiment of a sulfuric acid replenishment mechanism. [Figure 7] 10 is a flowchart showing yet another example of the flow related to the spare discard operation. [Figure 8]FIG. 10 is a piping diagram showing a fourth embodiment of a sulfuric acid replenishment mechanism. [Figure 9] FIG. 10 is a piping diagram showing a fifth embodiment of a sulfuric acid replenishment mechanism. DETAILED DESCRIPTION OF THE INVENTION

[0008] A schematic configuration of a substrate processing system 1 (an example of a liquid processing apparatus) according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing the schematic configuration of the substrate processing system 1 according to an embodiment. In the following, to clarify the positional relationship, mutually orthogonal X-axis, Y-axis, and Z-axis are defined, and the positive direction of the Z-axis is defined as the vertically upward direction.

[0009] As shown in FIG. 1, the substrate processing system 1 includes a loading / unloading station 2 and a processing station 3.

[0010] The loading / unloading station 2 includes a carrier mounting section 11 and a transport section 12. A plurality of carriers C are mounted on the carrier mounting section 11, each of which accommodates a plurality of substrates W (semiconductor wafers in this embodiment) to be processed in a horizontal position.

[0011] The transport section 12 is provided with a substrate transport device 13 and a transfer section 14. The substrate transport device 13 can transport the substrate W between the carrier C and the transfer section 14.

[0012] The processing station 3 includes a transport section 15 and a plurality of processing units 16 arranged side by side on both sides of the transport section 15 .

[0013] The transfer section 15 is provided with a substrate transfer device 17. The substrate transfer device 17 can transfer the substrate W between the delivery section 14 and any of the processing units 16.

[0014] The processing unit 16 supplies a processing fluid (processing liquid) to the substrate W, thereby performing liquid processing on the substrate W.

[0015] The processing liquid may be any processing liquid used in the technical field of semiconductor device manufacturing. Specific examples include chemical liquids such as DHF, SC1, and SC2, rinse liquids such as DIW (pure water), and low-surface-tension organic replacement liquids such as IPA (isopropyl alcohol). In an exemplary embodiment described below, SPM (sulfuric acid / hydrogen peroxide), SC1, two-fluid (DIW spray), and IPA are sequentially supplied to the substrate W in the processing unit 16.

[0016] The substrate processing system 1 includes a control device 4. The control device 4 is, for example, a computer, and includes a control calculation unit 18 and a storage unit 19. The storage unit 19 stores programs for controlling various processes executed in the substrate processing system 1. The control calculation unit 18 controls the operation of the substrate processing system 1 by reading and executing the process recipes and control programs stored in the storage unit 19.

[0017] The processing recipe and control program may be recorded on a computer-readable storage medium and installed from the storage medium into the storage unit 19 of the control device 4. Examples of computer-readable storage media include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnetic optical disk (MO), and a memory card.

[0018] In the above-described substrate processing system 1, first, the substrate transport device 13 in the loading / unloading station 2 takes out the substrate W from the carrier C placed on the carrier placement section 11, and places the taken-out substrate W on the transfer section 14. The substrate W placed on the transfer section 14 is then taken out of the transfer section 14 by the substrate transport device 17 in the processing station 3, and carried into the processing unit 16.

[0019] The substrate W carried into the processing unit 16 is processed by the processing unit 16, and then carried out of the processing unit 16 by the substrate transfer device 17 and placed on the transfer section 14. Then, the processed wafer W placed on the transfer section 14 is returned by the substrate transfer device 13 to the original carrier C on the carrier placement section 11.

[0020] [Configuration of processing liquid supply mechanism] Next, a processing liquid supply mechanism that supplies processing liquid to each processing unit 16 will be described with reference to FIG. 2. Processing liquids include various liquids, such as chemical liquids, rinse liquids such as DIW (pure water), and organic solvents such as IPA (isopropyl alcohol). Here, only the chemical liquid supply mechanism of the processing liquid supply mechanism, particularly the sulfuric acid supply mechanism 100 of the SPM supply mechanism that supplies SPM (sulfuric acid / hydrogen peroxide mixture, which is a mixture of sulfuric acid and hydrogen peroxide) as the chemical liquid, will be described. As for other processing liquid supply mechanisms, known mechanisms in the technical field of semiconductor manufacturing equipment can be appropriately selected and used, and illustrations and descriptions of these mechanisms will be omitted.

[0021] The sulfuric acid supply mechanism 100 includes a tank 102 (storage tank) for storing sulfuric acid and a circulation line 104. The tank 102 contains:

[0022] The circulation line 104 includes, in order from the side closest to the tank 102 (upstream side), a pump 106 and A filter 108, an on-off valve 110, a heater (in-line heater) 112, a flow meter 114, an on-off valve 116, and a back pressure valve 118 are provided.

[0023] The circulation line 104 is provided with a branch supply line connection area 120. In the branch supply line connection area 120, a plurality of branch supply lines 122 branch off from the circulation line 104. In Figure 2, only one of the plurality of branch supply lines 122 is shown in its entirety, and only the upstream ends of the other two branch supply lines 122 are indicated by arrows.

[0024] The branch supply line 122 is provided with, in order from the upstream side, a flow meter 124, a flow control valve 126, and an on-off valve 128. A nozzle 130 is provided at the downstream end of the branch supply line 122 within the processing unit 16. The processing unit 16 is provided with a spin chuck 161 (substrate holding and rotating unit) that holds the substrate W in a horizontal position and rotates it about a vertical axis. The nozzle 130 is supported by a nozzle arm (not shown) and can dispense a chemical solution (in this embodiment, SPM, a mixture of sulfuric acid and hydrogen peroxide) to any radial position of the substrate W held and rotated by the spin chuck 161. The processing unit 16 also has one or more nozzles for dispensing other processing solutions (such as the aforementioned SC1, IPA, and DIW), but these nozzles are not shown. The configuration of the processing unit 16 is well known in the technical field of semiconductor manufacturing equipment, and therefore a detailed description thereof will be omitted.

[0025] A branch return line 132 branches off from the branch supply line 122 between the flow control valve 126 and the on-off valve 128. The number of branch return lines 132 is the same as the number of branch supply lines 122 (i.e., the same as the number of processing units 16). Each branch return line 132 is provided with an on-off valve 134. The multiple branch return lines 132 join with a main return line 136 at a branch return line joining region 138 provided in the main return line 136. The main return line 136 is connected to the tank 102. In FIG. 2, only one of the multiple branch return lines 132 is shown in its entirety, and only the downstream ends of the other two branch return lines 132 are indicated by arrows.

[0026] Downstream of the branch supply line connection region 120, the circulation line 104 is provided with an on-off valve 116 and a constant pressure valve 118. The constant pressure valve 118 maintains the pressure of the sulfuric acid in the branch supply line connection region 120 at a substantially constant level, thereby facilitating control of the flow rate of the sulfuric acid flowing through each branch supply line 122.

[0027] Downstream of the branch return line junction area 138, the main return line 136 is provided with an on-off valve 144 and a constant pressure valve 146.

[0028] When SPM is not being supplied to the substrate W from the nozzle 130, the on-off valve 128 is closed and the on-off valve 134 is opened, so that the hot sulfuric acid always flows through a part of the branch supply line 122 and the branch return line 132. This prevents the sulfuric acid from cooling in the branch supply line 122, and reduces the amount of liquid required for pre-dispensing to restore the temperature.

[0029] During normal operation of the substrate processing system, sulfuric acid in the tank 102 circulates through the circulation line 104 and is heated by the heater 112 during circulation. Sulfuric acid is supplied to each processing unit 16 via a branch supply line 122 according to the processing schedule of the substrate processing system. As schematically indicated by the arrow labeled H2O2 in FIG. 2, hydrogen peroxide is supplied to the branch supply line 122 from the supply line of the hydrogen peroxide supply mechanism at a position before the nozzle 130. This hydrogen peroxide is mixed with sulfuric acid flowing through the branch supply line 122, thereby generating SPM, which is a mixture of sulfuric acid and hydrogen peroxide. The SPM is supplied from the nozzle 130 to the rotating substrate W, and the substrate W is subjected to SPM processing (chemical processing).

[0030] During normal operation of the substrate processing system, substrates W are processed one after another in each processing unit 16, and as a result, the amount of sulfuric acid in the tank 102 decreases. When the liquid level sensor 103 detects that the liquid level of the sulfuric acid in the tank 102 has dropped to a predetermined lower limit level, sulfuric acid is replenished into the tank 102. The configuration for replenishing the sulfuric acid (sulfuric acid replenishment mechanism 200) will be described below. It should be noted that the sulfuric acid replenishment mechanism (processing liquid replenishment mechanism) 200 is also used to supply new sulfuric acid to an empty tank.

[0031] The sulfuric acid replenishment mechanism 200 has a sulfuric acid replenishment line 204 connecting the sulfuric acid supply source 202 and the tank 102. The sulfuric acid supply source 202 is provided, for example, as a factory utility of the semiconductor device manufacturing factory in which the substrate processing system 1 is installed. In this case, the sulfuric acid supply source 202 is an auxiliary facility of the semiconductor device manufacturing factory and is not part of the substrate processing system 1. The sulfuric acid supply source 202 may be composed of a tank containing a processing liquid provided by a chemical liquid manufacturer, and a pressure-feeding mechanism that supplies pressurized inert gas to the tank and pumps sulfuric acid from the tank.

[0032] The sulfuric acid replenishment line 204 is provided with, in order from the upstream side, an on-off valve 206, a filter 208, a flow meter 210, and an on-off valve 212. A drainage line 216 branches off from the sulfuric acid replenishment line 204 at a branch point 214 on the secondary side of the filter 208, in other words, on the downstream side of the filter 208. The drainage line 216 is provided with an on-off valve 218. The downstream end of the drainage line 216 is connected to, for example, a factory waste liquid passage.

[0033] The operation of the sulfuric acid replenishment mechanism 200 will be described below. During normal operation of the substrate processing system, when the liquid level sensor 103 detects that the liquid level of sulfuric acid in the tank 102 has dropped to a predetermined lower limit, the on-off valves 206 and 212 in the processing liquid replenishment line 204 are opened while the on-off valve 218 in the drain line 216 is closed. This allows sulfuric acid to be supplied (replenished) to the tank 102 from the sulfuric acid supply source 202 via the sulfuric acid replenishment line 204. When the liquid level sensor 103 detects that the liquid level of sulfuric acid in the tank 102 has reached a predetermined upper limit, the on-off valves 206 and 212 are closed, and the replenishment of sulfuric acid to the tank 102 is stopped.

[0034] When the operation of the substrate processing system is restarted after being stopped for a relatively long time, the sulfuric acid that has accumulated in the sulfuric acid replenishment line 204 during the operation stoppage is temporarily discarded via the drain line 216, and then the tank 102 is replenished with sulfuric acid in response to a sulfuric acid replenishment request. In other words, the sulfuric acid that has accumulated in the sulfuric acid replenishment line 204 for a long time is discarded without being supplied to the tank 102. This operation is called a "preliminary discard operation."

[0035] If sulfuric acid remains in the sulfuric acid replenishment line 204 for a long period of time, contaminants such as particles trapped in the filter 208 (especially particles smaller than the pores that adhere to the surface of the filter element by a non-sieving mechanism) may become detached from the filter 208. Furthermore, contaminants adhering to the on-off valve 206 and the sulfuric acid replenishment line (piping) 204 may become detached or eluted into the sulfuric acid. Supplying sulfuric acid containing such contaminants to the tank 102 increases the amount of contaminants contained in the sulfuric acid flowing through the circulation line 104. While the filter 108 installed in the circulation line 104 can remove contaminants such as particles, it cannot completely remove them. This may increase the amount of particles adhering to the substrates W processed in the processing unit 16. Therefore, it is desirable to maintain high purity of the sulfuric acid supplied to the tank 102 via the sulfuric acid replenishment line 204. For this purpose, a preliminary disposal operation is performed.

[0036] An example of a specific flow related to the spare discard operation is shown in Figure 3.

[0037] Using a timer function attached to the control device 4, the elapsed time is measured from the end of the last refill of sulfuric acid into the tank 102 (step S301 in FIG. 3). When it is detected that the liquid level in the tank 102 has dropped to the lower limit liquid level, the control device 4 determines that it is necessary to refill (supply) sulfuric acid into the tank 102 (step S302). Next, the control device 4 determines whether the elapsed time exceeds a predetermined threshold value (step S303).

[0038] If it is determined that the threshold value is exceeded (Yes in step S303), a preliminary disposal operation is performed (step S304). In the preliminary disposal operation, the on-off valve 206 of the sulfuric acid replenishment line 204 and the on-off valve 218 of the drain line 216 are opened while the on-off valve 212 of the sulfuric acid replenishment line 204 is closed. As a result, new sulfuric acid flows from the sulfuric acid supply source 202 into the sulfuric acid replenishment line 204, and the sulfuric acid that has flowed in is discharged from the drain line 216. As a result, sulfuric acid containing contaminants such as particles that has accumulated upstream of the branch point 214 of the sulfuric acid replenishment line 204 is discharged via the drain line 216.

[0039] The preliminary discarding operation is performed for a predetermined time using the timer function. Alternatively, the preliminary discarding operation may be performed until the integrated flow rate of sulfuric acid during the preliminary discarding operation reaches a predetermined value. The integrated flow rate of sulfuric acid can be determined, for example, by integrating the detected value of the flow meter 210 provided in the sulfuric acid replenishment line 204 over time.

[0040] The predetermined time or the predetermined value of the integrated flow rate can be determined based on the amount of retained sulfuric acid (which roughly corresponds to the internal volume of the sulfuric acid replenishment line 204 upstream of the branch point 214, for example) and the discharge flow rate of sulfuric acid during the preliminary discard operation. For example, the conditions of the preliminary discard operation can be determined so that sulfuric acid in an amount, for example, five times the amount of retained sulfuric acid (this amount is determined based on a preliminary experiment, taking into account a safety margin) is discarded through the drain line 216.

[0041] After the preliminary discarding operation is completed, the on-off valve 218 of the drainage line 216 is closed, and the on-off valve 212 of the sulfuric acid replenishment line 204 is opened, and sulfuric acid is replenished into the tank 102 (step S305). When the required amount of sulfuric acid has been replenished, the on-off valves 206 and 212 of the sulfuric acid replenishment line 204 are closed (S306), the timer is reset, and the elapsed time is measured again from the reset point (S301).

[0042] If it is determined in step S303 that the threshold value is not exceeded (No), the on-off valves 206, 212 of the sulfuric acid replenishment line 204 are opened with the on-off valve 218 of the drainage line 216 closed, and sulfuric acid is replenished into the tank 102, without performing the above-described preliminary disposal operation. In this case as well, when the replenishment of sulfuric acid is completed, the on-off valves 206, 212 of the sulfuric acid replenishment line 204 are closed, the timer is reset, and the elapsed time is measured again starting from the reset point.

[0043] During the preliminary discard operation, the flow rate of the sulfuric acid flowing through the sulfuric acid replenishment line 204 may be changed. This can enhance the effectiveness of the preliminary discard operation in discharging contaminants such as particles. Such a change in flow rate can be achieved by providing a flow control valve upstream of the branch point 214 in the sulfuric acid replenishment line 204.

[0044] Another example of a specific flow is shown in Figure 4. This flow differs from the float in Figure 3, which determines whether or not a reserve disposal operation is necessary when it is determined that a chemical solution needs to be supplied, in that reserve disposal is performed periodically.

[0045] Using a timer function attached to the control device 4, the elapsed time is measured from the end of the last sulfuric acid replenishment or the end of the last preliminary disposal operation (step S311 in FIG. 4). If it is determined that the elapsed time exceeds a predetermined threshold (Yes in step S312), the on-off valve 212 of the sulfuric acid replenishment line 204 is closed, and the on-off valve 206 of the sulfuric acid replenishment line 204 and the on-off valve 218 of the drainage line 216 are opened, and the preliminary disposal operation is performed (step S313). At the end of the preliminary disposal operation, the timer is reset, and the elapsed time is measured again from the reset point. Every time the elapsed time reaches the predetermined threshold, the preliminary disposal operation is performed (a loop of steps S312 and S313).

[0046] If the liquid level sensor 103 detects that the liquid level in the tank 102 has dropped to the lower limit level when the elapsed time has not yet reached a predetermined threshold (No in step S312), the control device 4 determines that the tank 102 needs to be replenished with sulfuric acid (step S314). Then, the control device 4 opens the on-off valves 206 and 212 in the sulfuric acid replenishment line 204 while keeping the on-off valve 218 in the drainage line 216 closed, thereby replenishing the tank 102 with sulfuric acid (step S315). When the required amount of sulfuric acid has been replenished, the on-off valves 206 and 212 in the sulfuric acid replenishment line 204 are closed (step S316), the timer is reset, and the elapsed time is measured again starting from the reset point (step S311).

[0047] Next, another embodiment of the sulfuric acid replenishment mechanism (hereinafter also referred to as the second embodiment) will be described with reference to Figure 5. The second embodiment differs from the embodiment shown in Figure 2 (hereinafter also referred to as the first embodiment) in that an additional drainage line 222 is further provided, but is otherwise the same as the first embodiment. The same members as in the first embodiment are given the same reference numerals, and duplicate explanations will be omitted. When the sulfuric acid replenishment mechanism according to the second embodiment is used, the configuration of the sulfuric acid supply mechanism, excluding the sulfuric acid replenishment mechanism (not shown), is the same as that shown in Figure 2.

[0048] 5, the additional drain line 222 branches off from the sulfuric acid replenishment line 204 at a branch point 220 set on the primary side (upstream side) of the filter 208, more specifically, between the on-off valve 206 and the filter 208. The additional drain line 222 is provided with an on-off valve 224. In the following description, the drain line 216 will also be referred to as the first drain line 216, and the additional drain line 222 will also be referred to as the second drain line 222.

[0049] The operation of the sulfuric acid replenishment mechanism 200 of the second embodiment will be described below. During normal operation of the substrate processing system, when the liquid level sensor 103 detects that the liquid level of sulfuric acid in the tank 102 has dropped to a predetermined lower limit, the on-off valves 206 and 212 in the sulfuric acid replenishment line 204 are opened while the on-off valve (first drainage on-off valve) 218 ​​in the first drainage line 216 and the on-off valve (second drainage on-off valve) 222 in the second drainage line 222 are closed. This allows sulfuric acid to be supplied (replenished) to the tank 102 from the sulfuric acid supply source 202 via the sulfuric acid replenishment line 204. When the liquid level sensor 103 detects that the liquid level of sulfuric acid in the tank 102 has reached a predetermined upper limit, the on-off valves 206 and 212 in the sulfuric acid replenishment line 204 are closed, and the replenishment of sulfuric acid to the tank 102 is stopped.

[0050] When sulfuric acid remains in the sulfuric acid replenishment line 204 for a long period of time, a preliminary discarding operation is carried out as in the first embodiment. The preliminary discarding operation in the second embodiment comprises a first preliminary discarding operation that is carried out first, and a second preliminary discarding operation that is carried out subsequent to the first preliminary discarding operation.

[0051] When performing the first preliminary discard operation, the on-off valve 218 of the first drain line 216 and the on-off valve 212 of the sulfuric acid replenishment line 204 are closed, and the on-off valve 224 of the second drain line 222 is opened. Then, new sulfuric acid flows from the sulfuric acid supply source 202 into the sulfuric acid replenishment line 204, and the inflowing sulfuric acid is discharged from the second drain line 222. As a result, sulfuric acid containing contaminants such as particles that have been retained upstream of the branch point 220 of the sulfuric acid replenishment line 204 (on the primary side of the filter 208) is discharged.

[0052] For example, if the sulfuric acid supply source 202 is a factory utility, contaminants such as particles may be released or eluted into the sulfuric acid if sulfuric acid stagnates at the connection with the sulfuric acid replenishment line 204 of the factory utility or in the sulfuric acid flow path upstream of the connection. Also, contaminants such as particles may be released or eluted into the sulfuric acid in the upstream portion of the filter 208 of the sulfuric acid replenishment line 204. By performing the first preliminary disposal operation, it is possible to discharge the sulfuric acid containing such contaminants.

[0053] The first preliminary discard operation is performed for a predetermined time using the timer function described above. The first preliminary discard operation may be performed until the integrated flow rate of sulfuric acid during the preliminary discard operation reaches a predetermined value. In the configuration of FIG. 5, the integrated flow rate during the first preliminary discard operation cannot be measured using the flow meter 210. Therefore, if it is desired to measure the integrated flow rate, the position of the flow meter 210 may be changed to a position where the flow rate of sulfuric acid discharged through the second drain line 222 can be measured (for example, a position upstream of the branch point 220 of the sulfuric acid replenishment line 204), or another flow meter may be provided in the second drain line 222.

[0054] When the first preliminary discarding operation is completed, the second preliminary discarding operation is started. To perform the second preliminary discarding operation, the on-off valve 212 of the sulfuric acid replenishment line 204 is kept closed, the on-off valve 224 of the second drainage line 222 is closed, and the on-off valve 218 of the first drainage line 216 is opened. Then, new sulfuric acid flows from the sulfuric acid supply source 202 into the sulfuric acid replenishment line 204, and the sulfuric acid that has flowed in is discharged from the first drainage line 216. As a result, sulfuric acid containing contaminants such as particles that have been retained in the filter 208 of the sulfuric acid replenishment line 204 and downstream of the filter 208 is discharged.

[0055] The second preliminary discarding operation is performed for a predetermined time using the timer function described above. The second preliminary discarding operation may be performed until the integrated flow rate of sulfuric acid during the preliminary discarding operation reaches a predetermined value.

[0056] When performing the above-mentioned first spare discard operation and second spare discard operation, the operations can be performed according to the flowcharts of Figures 3 and 4. In this case, "spare discard (operation)" in the flowcharts can be read as "first spare discard (operation)" and "second spare discard (operation)."

[0057] Next, still another embodiment of the sulfuric acid replenishment mechanism (hereinafter also referred to as the third embodiment) will be described with reference to FIG. 6. The second embodiment differs from the first embodiment shown in FIG. 2 in that a liquid particle counter (particle detector) 240 (hereinafter referred to as "LPC") is provided in the sulfuric acid replenishment line 204, but is otherwise the same as the first embodiment. The same members as those in the first embodiment are designated by the same reference numerals, and duplicated explanations will be omitted. Even when the sulfuric acid replenishment mechanism according to the third embodiment is used, the configuration of the sulfuric acid supply mechanism, excluding the sulfuric acid replenishment mechanism (not shown), is the same as that shown in FIG. 2.

[0058] As shown in FIG. 6, the LPC 240 is provided on the sulfuric acid replenishment line 204 on the secondary side (downstream side) of the filter 208 and upstream of the branch point 214 of the drain line 216.

[0059] A specific example of operation related to the spare discard operation in the third embodiment will be described below.

[0060] (Operation example 1) When the liquid level sensor 103 detects that the level of the sulfuric acid in the tank 102 has dropped to the lower limit level, the control device 4 determines that it is necessary to supply the chemical solution. Then, the control device 4 opens the on-off valve 206 of the sulfuric acid replenishment line 204 and the on-off valve 218 of the drain line 216 while keeping the on-off valve 212 of the sulfuric acid replenishment line 204 closed, and performs a preliminary drain operation to drain the sulfuric acid that has accumulated in the sulfuric acid replenishment line 204. During this draining process, the LPC 240 detects the amount of particles contained in the sulfuric acid passing through it.

[0061] Alternatively, the LPC 240 may detect the particle amount in real time, and the control device 4 may determine in real time whether the particle amount exceeds a predetermined threshold. Alternatively, the LPC 240 may sample data at predetermined time intervals, and the control device 4 may determine whether the particle amount exceeds a predetermined threshold based on the average value of multiple sampled data. Alternatively, the LPC 240 may sample data at predetermined time intervals, and the control device 4 may determine whether the particle amount exceeds a predetermined threshold based on a moving average of the sampled data. Hereinafter, in this specification, the particle amount compared with the threshold may be any of the above-mentioned real-time measurement value, average value, and moving average.

[0062] When it is detected that the amount of particles has fallen below a predetermined threshold, the control device 4 stops the preliminary disposal operation and starts replenishing the tank 102 with sulfuric acid. That is, the control device 4 closes the on-off valve 218 of the drain line 216 and opens the on-off valve 212 of the sulfuric acid replenishing line 204 while leaving the on-off valve 206 of the sulfuric acid replenishing line 204 open. When the liquid level sensor 103 detects that the level of sulfuric acid in the tank 102 has reached a predetermined upper limit level, the on-off valves 206 and 212 of the sulfuric acid replenishing line 204 are closed, and the replenishing of sulfuric acid to the tank 102 is stopped.

[0063] If the amount of particles detected by the LPC 240 exceeds a predetermined threshold value (due to some abnormality) while the tank 102 is being replenished with sulfuric acid, the control device 4 closes the on-off valve 212 of the sulfuric acid replenishment line 204 and opens the on-off valve 218 of the drainage line 216. This stops the replenishment of sulfuric acid into the tank 102, and the preliminary drainage operation is performed again.

[0064] (Operation example 2) A second example of operation related to the spare discard operation in the third embodiment will be described with reference to the flowchart of FIG.

[0065] After the previous replenishment of sulfuric acid into the tank 102 is completed, when the time for the next replenishment approaches, the LPC 240 measures the amount of particles in the sulfuric acid remaining in the sulfuric acid replenishment line 204. During normal operation of the substrate processing system, the liquid in the tank 102 decreases at a generally constant pace. Therefore, the approaching time for the next replenishment can be detected by the timer described above based on the elapsed time since the end of the sulfuric acid replenishment. If the liquid level detection device attached to the tank 102 is configured to detect that the liquid level in the tank 102 is slightly higher than the lower limit liquid level, the liquid level detection device can detect that the time for the next replenishment is approaching.

[0066] When the sulfuric acid is stationary in the sulfuric acid replenishment line 204, the LPC 240 cannot meaningfully measure the particle amount. This is because the problematic particles diffuse into the sulfuric acid when the sulfuric acid starts moving. For this reason, the measurement of the particle amount in the sulfuric acid (step S321 in FIG. 7) is performed while the sulfuric acid is moving, in this case, while preliminary discarding is being performed. As in the first embodiment, preliminary discarding is performed by opening the on-off valves 206 and 218 while the on-off valve 212 is closed.

[0067] The amount of particles measured by the LPC 240 is compared with a predetermined threshold value (step S322).

[0068] If the amount of particles is greater than the threshold value (Yes in step S322), a preliminary discard operation is performed (step S323). If a moving average is being measured as described above, the preliminary discard operation is continued as is. After the timer detects that the preliminary discard operation has been performed for a predetermined time (or after it is confirmed that a predetermined amount of sulfuric acid has been discarded from the drain line 216 based on the detection value of the flow meter 210), the amount of particles measured by the LPC 240 is compared with a predetermined threshold value (step S324).

[0069] If the amount of particles becomes smaller than a predetermined threshold value (Yes in step S324), the control device 4 recognizes that there is no problem in refilling sulfuric acid into the tank 102. If the determination result in step S322 is No, the control device 4 also recognizes that there is no problem in refilling sulfuric acid into the tank 102, and the flow proceeds to step S325.

[0070] In this state, when the liquid level sensor 103 detects that the liquid level of sulfuric acid in the tank 102 has dropped to the lower limit liquid level, the control device 4 determines that sulfuric acid should be replenished to the tank 102 (step S325). The control device 4 closes the on-off valve of the discharge line 216 and opens the on-off valves 206 and 212 of the sulfuric acid replenishment line 204, and starts replenishment of sulfuric acid to the tank 102 (step S326). When the liquid level sensor 103 detects that the liquid level of sulfuric acid in the tank 102 has reached a predetermined upper limit liquid level, the on-off valves 206 and 212 of the sulfuric acid replenishment line 204 are closed, and the replenishment of sulfuric acid to the tank 102 is stopped (step S327).

[0071] If the determination result in step S324 is No, it is determined whether the total execution time of the preliminary discard operation is less than a predetermined time (step S328). If the determination result in step S328 is Yes, the preliminary discard operation continues to be performed until the particle amount becomes smaller than a predetermined threshold (a loop of steps S323, S324, and S328).

[0072] If the determination result in step S328 is No, the control device 4 determines that there is some factor (for example, an abnormality in the sulfuric acid supply source 202 as a factory utility) that prevents the particle amount from being reduced to less than the predetermined threshold by the preliminary discard operation. Then, the control device 4 generates an alarm using the user interface of the substrate processing system 1 to prompt the operator to perform an inspection.

[0073] 6, when the amount of particles detected by the LPC 240 exceeds a predetermined threshold while the tank 102 is being replenished with sulfuric acid, the on-off valve 212 may be immediately closed and the on-off valve 218 may be opened. This makes it possible to prevent contaminated sulfuric acid from being supplied to the tank 102 even if the amount of particles suddenly increases.

[0074] If the LPC 240 is configured to be able to detect the amount of particles for each particle size, a criterion (threshold) for determining the amount of particles may be set for each particle size.

[0075] Next, still another embodiment of the sulfuric acid replenishment mechanism (hereinafter also referred to as the fourth embodiment) will be described with reference to Fig. 8. The fourth embodiment differs from the first embodiment in that a preliminary discard operation is performed using heated sulfuric acid, but is otherwise the same as the first embodiment.

[0076] In the fourth embodiment, a bypass line 263 for heating is connected to connection points 261, 262 set between the on-off valve 206 and the filter 208 of the sulfuric acid replenishment line 204. An on-off valve 264 and a heater 265 are provided in the bypass line 263, in this order from the upstream side. An on-off valve 267 is provided between the on-off valve 206 and the filter 208 of the sulfuric acid replenishment line 204 (hereinafter, for convenience of explanation, also referred to as the "main line portion 266"). By switching the on-off valves 264, 267, sulfuric acid supplied from the sulfuric acid supply source 202 can be made to flow only through either the main line portion 266 or the bypass line 263.

[0077] In the fourth embodiment, the determination of whether or not the preliminary disposal operation is necessary is made in the same manner as in the first embodiment. In the fourth embodiment, when the preliminary disposal operation is performed, the on-off valves 206, 264, and 218 are opened while the on-off valves 267 and 212 are closed, and the heater 265 is turned on (energized). At this time, the sulfuric acid that has flowed from the sulfuric acid supply source 202 into the sulfuric acid replenishment line 204 flows into and passes through the bypass line 263, and then flows back into and down the sulfuric acid replenishment line 204 and then is discharged through the drain line 216.

[0078] As the sulfuric acid passes through the bypass line 263, it is heated by the heater 265, and the heated sulfuric acid passes through the filter 208. This causes particles adhering to the surface of the filter element to detach from the filter element by the non-sieving mechanism described above and flow out of the filter 208. In other words, the preliminary disposal operation can actively clean the filter 208, thereby extending the life of the filter.

[0079] This pre-disposal operation involving cleaning the filter 208 with heated sulfuric acid does not have to be performed every time a pre-disposal operation is performed. For example, it may be performed once every 10 pre-disposal operations. Alternatively, it may be performed when maintenance is performed on the processing liquid supply mechanism. When performing a normal pre-disposal operation (not using heated sulfuric acid), it is sufficient to open the on-off valves 206, 267, and 218 while keeping the on-off valves 264 and 212 closed.

[0080] It is preferable to make the flow resistance of the bypass line 263 greater than the flow resistance of the main line portion 266. This is because the heating efficiency increases when the flow rate of sulfuric acid passing through the heater 265 is reduced. For this purpose, the pipe diameter of the bypass line 263 may be reduced, or an appropriate throttle may be provided in the bypass line 263. The on-off valve 264 may be replaced with a needle valve having a full-closing function.

[0081] Next, still another embodiment of the sulfuric acid replenishment mechanism (hereinafter also referred to as the fifth embodiment) will be described with reference to Fig. 9. The fifth embodiment differs from the first embodiment in that a preliminary discard operation is performed using heated sulfuric acid, but is otherwise the same as the first embodiment.

[0082] In the fifth embodiment, the filter 208 is provided with a heater (heating device) that heats the filter 208 or a vibration device that applies vibration to the filter 208. The heating device or vibration device is schematically indicated by a dashed square box labeled with reference numeral 280. By heating the filter 208 or applying vibration to the filter 208, particles adhering to the filter element surface are more likely to detach from the filter element by the non-sieving mechanism described above. Heating the filter 208 or applying vibration to the filter 208 may be performed simultaneously with the preliminary discarding operation or may be started slightly before the preliminary discarding operation. In the latter case, the preliminary discarding operation can be performed more efficiently and the time required for the preliminary discarding operation can be shortened. In this fifth embodiment, the filter cleaning effect can also extend the filter's lifespan.

[0083] According to the above embodiment, it is possible to prevent the processing liquid containing contaminants such as particles from flowing into the tank 102. As a result, it is possible to suppress a decrease in the cleanliness of the processing liquid supplied to the substrate W in each processing unit 16, and it is possible to prevent the level of particle contamination of the substrate W from worsening.

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

[0085] The substrate to be processed is not limited to a semiconductor wafer, but may be a variety of substrates used in the field of semiconductor device manufacturing, such as a glass substrate, a ceramic substrate, etc. The processing liquid is also not limited to sulfuric acid, but may be any processing liquid used in semiconductor manufacturing, such as hydrogen peroxide solution or IPA. [Explanation of symbols]

[0086] W substrate 4. Control unit (control device) 16 Processing Unit 102 Tank 202 Processing liquid supply source 204 Refill Line 212 Refill on-off valve 216 First drainage line 218 First drainage on-off valve

Claims

1. a processing unit for performing liquid processing on a substrate using a processing liquid; a tank for storing the processing liquid before it is supplied to the processing unit; a replenishment line for supplying processing solution from a processing solution source to the tank; a refilling on-off valve that opens and closes the refilling line; a first drainage line branching from the refilling line upstream of the refilling on-off valve; a first drainage on-off valve that opens and closes the first drainage line; A control unit; Equipped with The control unit controls the operation of the replenishment on-off valve and the first drainage on-off valve to perform a preliminary disposal operation in which the processing liquid flowing from the processing liquid supply source into the replenishment line is drained through the first drainage line before replenishment of the processing liquid from the processing liquid supply source into the tank through the replenishment line begins.

2. 2. The substrate processing apparatus according to claim 1, wherein the refill line is provided with a filter, and the first drain line branches off from the refill line on a secondary side of the filter.

3. 2 . The substrate processing apparatus according to claim 1 , wherein the control unit causes the preliminary discarding operation to be performed when the processing liquid has not been continuously replenished into the tank through the replenishment line for more than a predetermined time.

4. 4. The substrate processing apparatus according to claim 3, wherein the control unit causes the preliminary disposal operation to be performed for a predetermined time or until a predetermined amount of the processing liquid is discharged from the first drain line.

5. 3. The substrate processing apparatus according to claim 2, further comprising a particle detector that detects an amount of particles contained in the processing liquid in the refill line, and wherein the control unit causes the preliminary discarding operation to be performed when the amount of particles detected by the particle detector exceeds a predetermined threshold.

6. The substrate processing apparatus according to claim 5 , wherein the control unit causes the preliminary discarding operation to be performed until the amount of particles detected by the particle detector becomes less than a predetermined threshold value.

7. a second drain line branching off from the refill line on the upstream side of the filter; a second drainage on-off valve that opens and closes the second drainage line; Furthermore, 3. The substrate processing apparatus of claim 2, wherein the control unit controls the operation of the replenishment on-off valve, the first drainage on-off valve, and the second drainage on-off valve to perform a first preliminary disposal operation in which the processing liquid flowing from the processing liquid supply source into the replenishment line is drained through the second drainage line before replenishment of the processing liquid from the processing liquid supply source through the replenishment line is started to the tank, and then performs a second preliminary disposal operation in which drainage through the second drainage line is stopped and the processing liquid is drained through the first drainage line.

8. 8. The substrate processing apparatus according to claim 7, wherein the control unit causes the first preliminary discarding operation and the second preliminary discarding operation to be performed when the processing liquid has not been continuously replenished to the tank via the replenishment line for more than a predetermined time.

9. 9. The substrate processing apparatus of claim 8, wherein the control unit causes a first preliminary discard operation to be performed for a predetermined time or until a predetermined amount of processing liquid is discharged from the second drain line, and thereafter causes a second preliminary discard operation to be performed for a predetermined time or until a predetermined amount of processing liquid is discharged from the second drain line.

10. 8. The substrate processing apparatus according to claim 7, further comprising a particle detector that detects an amount of particles contained in the processing liquid in the refill line, and wherein the control unit causes the first preliminary discarding operation and the second preliminary discarding operation to be performed when the amount of particles detected by the particle detector exceeds a predetermined threshold.

11. 11. The substrate processing apparatus according to claim 10, wherein the control unit causes the first preliminary discard operation to be performed for a predetermined time or until a predetermined amount of processing liquid is discharged from the second drain line, and thereafter causes the second preliminary discard operation to be performed until the amount of particles detected by the particle detector becomes less than a predetermined threshold.

12. 3. The substrate processing apparatus according to claim 2, wherein a heater is provided in the refill line upstream of the filter, and the control unit uses the heater to heat the processing liquid passing through the filter when the preliminary discarding operation is performed.

13. The substrate processing apparatus according to claim 2 , further comprising a heater for heating the filter, wherein the control unit heats the filter using the heater when the preliminary discarding operation is performed.

14. The substrate processing apparatus according to claim 2 , further comprising a vibrator that vibrates the filter, and the control unit vibrates the filter using the vibrator when the preliminary discarding operation is performed.

15. a processing unit for performing liquid processing on a substrate using a processing liquid; a tank for storing the processing liquid before it is supplied to the processing unit; a replenishment line for supplying processing solution from a processing solution source to the tank; a refilling on-off valve that opens and closes the refilling line; a first drainage line branching from the refilling line upstream of the refilling on-off valve; a first drainage on-off valve that opens and closes the first drainage line; In a substrate processing apparatus comprising the above, a processing liquid replenishment method for replenishing the processing liquid into the tank, comprising: A processing liquid replenishment method, comprising: a preliminary disposal operation for discharging the processing liquid flowing from the processing liquid supply source into the replenishment line through the first drain line before replenishment of the processing liquid from the processing liquid supply source into the tank through the replenishment line is started.

16. 16. The method for replenishing a processing liquid according to claim 15, wherein the replenishing line is provided with a filter, and the first drain line branches off from the replenishing line on the secondary side of the filter.

17. 16. The method of replenishing processing liquid according to claim 15, wherein the preliminary discarding operation is performed when the processing liquid has not been continuously replenished into the tank via the replenishment line for more than a predetermined time.

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