Substrate Processing Method and Substrate Processing Apparatus

Abstract

To provide a substrate processing method capable of suppressing a contamination of an air into a processing liquid.SOLUTION: In a substrate processing method, a processing liquid is exhausted from an inner tank 110, an outer tank 120, and a circulation pipe 141 (a first exhaust liquid step S1). After the exhaust of the processing liquid, the processing liquid is newly supplied to the inner tank 110 via a new liquid supply port 185 (a first supply step S2). After the supply of the new processing liquid into the inner tank 110, the processing liquid accumulated in the inner tank 110 is exhausted up to an inner tank lower limit level LVL (a second exhaust liquid step S3). After the exhaust of the processing liquid up to the inner tank lower limit level LVL, the new processing liquid is supplied to the inner tank 110 via the new liquid supply port 185 (a second supply step S4). The inner tank lower limit level LVL indicates a liquid level higher than a position of a circulation liquid introduction port 132 arranged to the inner part of the inner tank 110, and indicates the liquid level higher than the position of the new liquid supply port 185 arranged into the inner part of the inner tank 110.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a substrate processing method and a substrate processing apparatus.

Background Art

[0002] The substrate processing apparatus described in Patent Document 1 performs a predetermined process on a substrate by immersing the substrate in a processing liquid containing one or more chemical solutions and pure water. The substrate processing apparatus includes a processing tank and a processing liquid exchange unit. In the processing tank, a processing liquid for performing a predetermined process on the substrate is stored. The processing liquid exchange unit exchanges the processing liquid when the lifetime of the processing liquid in the processing tank has elapsed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the substrate processing apparatus described in Patent Document 1, air may be mixed into the processing liquid during the exchange of the processing liquid. For example, air in the circulation line for circulating the processing liquid may be mixed into the processing liquid during the exchange of the processing liquid. Or, for example, when discharging the chemical solution from the chemical solution discharge port of the chemical solution line and discharging the pure water from the pure water discharge port of the pure water line into the processing tank to exchange the processing liquid, air may be mixed into the processing liquid.

[0005] As a result of intensive research, the inventor of the present application has found that if air is mixed into the processing liquid, it may affect the processing of the substrate.

[0006] An object of the present invention is to provide a substrate processing method and a substrate processing apparatus capable of suppressing air from being mixed into the processing liquid.

Means for Solving the Problems

[0007] According to one aspect of the present invention, in the substrate processing method, the processing liquid is circulated in the inner tank by introducing the processing liquid that has overflowed from the inner tank storing the processing liquid into the inner tank through a circulation pipe and a circulation liquid inlet from an outer tank into which the processing liquid flows. The substrate processing method processes a substrate with the processing liquid in the inner tank. The substrate processing method includes a first drainage step, a first supply step, a second drainage step, and a second supply step. In the first drainage step, the processing liquid is discharged from the inner tank, the outer tank, and the circulation pipe. In the first supply step, after discharging the processing liquid in the first drainage step, a new processing liquid is newly supplied to the inner tank through a new liquid supply port, and the new processing liquid is newly stored in the inner tank. In the second drainage step, after newly supplying the processing liquid to the inner tank, the processing liquid stored in the inner tank is discharged to a lower limit level of the inner tank. In the second supply step, after discharging the processing liquid to the lower limit level of the inner tank, a new processing liquid is newly supplied to the inner tank through the new liquid supply port, and the processing liquid is newly stored in the inner tank. The lower limit level of the inner tank indicates a liquid level higher than the position of the circulation liquid inlet disposed inside the inner tank and also indicates a liquid level higher than the position of the new liquid supply port disposed inside the inner tank.

[0008] In one aspect of the present invention, it is preferable to execute the second drainage step and the second supply step a plurality of times respectively.

[0009] In one aspect of the present invention, it is preferable to determine the number of executions of the second drainage step and the second supply step according to the dissolved oxygen concentration in the processing liquid stored in the inner tank.

[0010] In one aspect of the present invention, in the second drainage step, it is preferable not to discharge the processing liquid stored in the outer tank.

[0011] In one aspect of the present invention, when the processing liquid in the inner tank is discharged to the lower limit level of the inner tank in the second liquid discharge step, it is preferable to stop the pump that is in operation. When the processing liquid is supplied to at least the upper limit level of the inner tank in the second supply step, it is preferable to circulate the processing liquid in the inner tank through the circulation pipe by driving the pump. The upper limit level of the inner tank preferably indicates a liquid level higher than the lower limit level of the inner tank in the inner tank.

[0012] In one aspect of the present invention, the processing liquid is preferably alkaline.

[0013] According to another aspect of the present invention, a substrate processing apparatus includes an inner tank, an outer tank, a circulating liquid introduction member, a circulation pipe, a drain pipe, a drain valve, a pump, a fresh liquid supply pipe, a supply valve, and a control unit. The inner tank stores a processing liquid. The outer tank is disposed outside the inner tank and into which the processing liquid overflowing from the inner tank flows. The circulating liquid introduction member has a circulating liquid inlet and introduces the processing liquid supplied from the outer tank through the circulating liquid inlet into the inner tank. The circulation pipe circulates the processing liquid stored in the inner tank by supplying the processing liquid from the outer tank to the circulating liquid introduction member. The drain pipe branches from the circulation pipe and discharges the processing liquid. The drain valve opens and closes the flow path of the drain pipe. The pump is disposed in the circulation pipe upstream of the drain pipe and sends out the processing liquid in the circulation pipe. The fresh liquid supply pipe has a fresh liquid supply port and newly supplies a processing liquid into the inner tank through the fresh liquid supply port. The supply valve opens and closes the flow path of the fresh liquid supply pipe. The control unit controls the drain valve, the pump, and the supply valve. The control unit controls the drain valve and the pump to discharge the processing liquid from the inner tank, the outer tank, and the circulation pipe. After discharging the processing liquid, the control unit controls the supply valve to newly supply the processing liquid into the inner tank. After newly supplying the processing liquid, the control unit controls the drain valve and the pump to discharge the processing liquid stored in the inner tank to a lower limit level of the inner tank. After discharging the processing liquid to the lower limit level of the inner tank, the control unit controls the supply valve to newly supply a processing liquid into the inner tank. The lower limit level of the inner tank indicates a liquid level higher than a position of the circulating liquid inlet disposed inside the inner tank and also indicates a liquid level higher than a position of the fresh liquid supply port disposed inside the inner tank.

Effect of the Invention

[0014] According to the present invention, it is possible to provide a substrate processing method and a substrate processing apparatus that can suppress air from being mixed into the processing liquid.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and the description will not be repeated. Also, in the drawings, for ease of understanding, the X-axis, Y-axis, and Z-axis are appropriately illustrated. The X-axis, Y-axis, and Z-axis are orthogonal to each other, the X-axis and Y-axis are parallel in the horizontal direction, and the Z-axis is parallel in the vertical direction.

[0017] Referring to FIGS. 1 to 13, the substrate processing apparatus 100 according to an embodiment of the present invention will be described. First, referring to FIGS. 1 to 3, the substrate processing apparatus 100 will be described. FIG. 1 is a schematic cross-sectional view showing the substrate processing apparatus 100. The substrate processing apparatus 100 shown in FIG. 1 is of a batch type and processes a plurality of substrates W collectively with a processing liquid LQ. The substrate processing apparatus 100 can also process a single substrate W.

[0018] The substrate processing apparatus 100 includes an inner tank 110, an outer tank 120, a substrate holding portion 125, a circulating liquid introduction portion 130, a circulation portion 140, and a control device CTL.

[0019] The inner tank 110 stores the processing liquid LQ in which a plurality of substrates W are immersed. The inner tank 110 can accommodate a plurality of substrates W. The inner tank 110 immerses a plurality of substrates W in the processing liquid LQ and processes the plurality of substrates W.

[0020] The processing liquid LQ is, for example, an etching liquid. For example, the polysilicon film formed on the substrate W is etched with the processing liquid LQ. In the present embodiment, as an example, the processing liquid LQ is alkaline. For example, the processing liquid LQ (etching liquid) may be an aqueous solution in which hydroxides of alkali metals such as sodium and potassium are dissolved (an aqueous solution of NaOH or an aqueous solution of KOH), or may be an aqueous solution in which a quaternary ammonium hydroxide such as TMAH (tetramethylammonium hydroxide) is dissolved. The quaternary ammonium hydroxide may be at least one of TMAH, TBAH (tetrabutylammonium hydroxide), TPeAH (tetrapentylammonium hydroxide), THAH (tetrahexylammonium hydroxide), TEAH (tetraethylammonium hydroxide), TPAH (tetrapropylammonium hydroxide), and choline hydroxide, or may be other than these. All of these are included in organic alkalis. Note that in this paragraph, TMAH represents an anhydride, not an aqueous solution. The same applies to other quaternary ammonium hydroxides such as TBAH.

[0021] The outer tank 120 is disposed outside the inner tank 110. The outer tank 120 surrounds the inner tank 110. The processing liquid LQ that has overflowed from the inner tank 110 flows into the outer tank 120. The height of the upper edge of the outer tank 120 is higher than the height of the upper edge of the inner tank 110.

[0022] The substrate holding unit 125 holds a plurality of substrates W. The substrate holding unit 125 can also hold a single substrate W. The substrate holding unit 125 immerses a plurality of substrates W arranged at intervals in the processing liquid LQ stored in the inner tank 110. The circulating liquid introduction unit 130 introduces the processing liquid LQ stored in the outer tank 120 into the inner tank 110. The circulating liquid introduction unit 130 is disposed inside the inner tank 110. The circulation unit 140 circulates the processing liquid LQ stored in the inner tank 110 by supplying the processing liquid LQ from the outer tank 120 to the circulating liquid introduction unit 130.

[0023] Continuing with reference to FIG. 1, the details of each component will be described. The circulating liquid introduction unit 130 includes a plurality of circulating liquid introduction members 131. In the example of FIG. 1, the circulating liquid introduction unit 130 includes two circulating liquid introduction members 131. However, the number of the circulating liquid introduction members 131 is not particularly limited and may be three or more. Also, the circulating liquid introduction unit 130 may include one circulating liquid introduction member 131.

[0024] The plurality of circulating liquid introduction members 131 are disposed inside the inner tank 110. Specifically, the plurality of circulating liquid introduction members 131 are disposed on the bottom side of the inner tank 110 inside the inner tank 110. Each of the plurality of circulating liquid introduction members 131 is, for example, a tube extending linearly.

[0025] Each of the plurality of circulating liquid introduction members 131 has a plurality of circulating liquid inlets 132. The circulating liquid inlet 132 is a through hole provided in the circulating liquid introduction member 131. The circulating liquid introduction member 131 introduces the processing liquid LQ supplied from the outer tank 120 through the circulating liquid inlet 132 into the inner tank 110. That is, the circulating liquid inlet 132 discharges the processing liquid LQ supplied from the outer tank 120 by the circulation unit 140 into the inner tank 110. Note that each of the plurality of circulating liquid introduction members 131 may have one circulating liquid inlet 132.

[0026] In the example of FIG. 1, the circulating liquid inlet 132 opens upward vertically. However, the direction of the circulating liquid inlet 132 is not particularly limited. For example, the circulating liquid inlet 132 may open obliquely upward and outward, or may open obliquely upward and inward. Also, for example, the circulating liquid inlet 132 may open obliquely downward and outward, or may open obliquely downward and inward. Also, for example, the circulating liquid inlet 132 may open downward vertically, or may open horizontally outward, or may open horizontally inward. Further, in each of the plurality of circulating liquid introduction members 131, the directions of the plurality of circulating liquid inlets 132 may be different. Also, between the plurality of circulating liquid introduction members 131, the directions of the circulating liquid inlets 132 may be different. Further, the heights of the plurality of circulating liquid introduction members 131 may be different.

[0027] The circulation section 140 includes a circulation pipe 141, a pump 142, a heater 143, a filter 144, an adjustment valve 145, and a valve 146. The pump 142, the heater 143, the filter 144, the adjustment valve 145, and the valve 146 are arranged in this order from the upstream to the downstream of the circulation pipe 141.

[0028] The circulation pipe 141 extends from the outer tank 120 to the circulating liquid introduction member 131. Then, the circulation pipe 141 circulates the processing liquid LQ stored in the inner tank 110 by supplying the processing liquid LQ from the outer tank 120 to the circulating liquid introduction member 131. Specifically, the upstream end of the circulation pipe 141 is located in the outer tank 120, and the downstream end of the circulation pipe 141 is connected to each circulating liquid introduction member 131. The circulation pipe 141 has an inlet 141x. The inlet 141x is located at the downstream end of the circulation pipe 141. The inlet 141x faces vertically downward. However, the direction of the inlet 141x is not particularly limited. The processing liquid LQ in the outer tank 120 enters the circulation pipe 141 from the inlet 141x. Note that, for example, the downstream end of the circulation pipe 141 may be connected to the bottom of the outer tank 120, and the inlet 141x may face vertically upward.

[0029] The pump 142 sends the processing liquid LQ in the circulation pipe 141 toward each circulation liquid introduction member 131. Therefore, the processing liquid LQ is supplied from the circulation pipe 141 to each circulation liquid introduction member 131. As a result, each circulation liquid introduction member 131 discharges the processing liquid LQ supplied from the circulation pipe 141 into the inner tank 110 from each circulation liquid inlet 132. The heater 143 heats the processing liquid LQ flowing through the circulation pipe 141 to adjust the temperature of the processing liquid LQ. The filter 144 filters the processing liquid LQ flowing through the circulation pipe 141. The adjustment valve 145 adjusts the opening degree of the circulation pipe 141 to adjust the flow rate of the processing liquid LQ supplied to the circulation liquid introduction member 131. The valve 146 opens and closes the circulation pipe 141. When circulating the processing liquid LQ, the valve 146 is open to open the flow path of the circulation pipe 141.

[0030] The control device CTL controls each component of the substrate processing apparatus 100. The control device CTL may include an input device and a display device.

[0031] Specifically, the control device CTL includes a control unit A1 and a storage unit A2. The control unit A1 includes a processor such as a CPU (Central Processing Unit). The storage unit A2 includes a storage device and stores data and computer programs. The processor of the control unit A1 executes the computer program stored in the storage device of the storage unit A2 to control each component of the substrate processing apparatus 100. Specifically, the control unit A1 controls the substrate holding unit 125 and the circulation unit 140. Also, for example, the storage unit A2 includes a main storage device such as a semiconductor memory and an auxiliary storage device such as a semiconductor memory and a hard disk drive. The storage unit A2 may include a removable medium such as an optical disk. The storage unit A2 is, for example, a non-transitory computer-readable storage medium.

[0032] Next, the substrate holding unit 125 will be described with reference to FIG. 2. FIGS. 2(a) and 2(b) are schematic perspective views of the substrate processing apparatus 100 before and after the substrate W is loaded into the inner tank 110. Note that in FIGS. 2(a) and 2(b), the processing liquid LQ is omitted for simplification of the drawing.

[0033] As shown in FIG. 2(a), the substrate holding part 125 includes a main body plate 126 and holding bars 127. The main body plate 126 is a plate extending in the vertical direction D. The holding bars 127 extend from one main surface of the main body plate 126 in a predetermined direction D10. The predetermined direction D10 is substantially parallel to the horizontal direction and substantially orthogonal to the main body plate 126. A plurality of substrates W are held in an upright posture (vertical posture) by the plurality of holding bars 127 in a state of being aligned at intervals.

[0034] In FIG. 2(a), the substrate holding part 125 is located above the inner tank 110. The substrate holding part 125 descends along the vertical direction D while holding a plurality of substrates W. Thereby, the plurality of substrates W are put into the inner tank 110. As shown in FIG. 2(b), when the substrate holding part 125 descends to the inner tank 110, the plurality of substrates W are immersed in the processing liquid LQ in the inner tank 110.

[0035] Note that, as shown in FIG. 1, the substrate holding part 125 may further include a lifting unit 128. The lifting unit 128 raises and lowers the main body plate 126 between a processing position (the position shown in FIG. 2(b)) where the plurality of substrates W held by the substrate holding part 125 are located in the inner tank 110 and a retracted position (the position shown in FIG. 2(a)) where the plurality of substrates W held by the substrate holding part 125 are located above the inner tank 110.

[0036] FIG. 3 is a schematic diagram showing the substrate processing apparatus 100. Note that, in FIG. 3, for simplification of the drawing, the substrate holding part 125, the adjustment valve 145, and the valve 146 are omitted. Further, in FIG. 3, a cross section along line III-III in FIG. 2(a) is shown for the inner tank 110 and the outer tank 120.

[0037] As shown in FIG. 3, the substrate processing apparatus 100 further includes an inner tank drainage unit 150, a drainage unit 160, a tank 170, a fresh liquid supply unit 180, a tank cleaning unit 190, an inner tank level sensor 210, an outer tank level sensor 220, and a sensor cleaning unit 230. The substrate processing apparatus 100 may further include a dissolved oxygen meter 240. The dissolved oxygen meter 240 measures the dissolved oxygen concentration of the processing liquid LQ and outputs information indicating the dissolved oxygen concentration to the control unit A1. The dissolved oxygen meter 240 measures the dissolved oxygen concentration of the processing liquid LQ by, for example, the diaphragm polarograph method.

[0038] When discharging the processing liquid LQ from the inner tank 110, the inner tank drainage unit 150 supplies the processing liquid LQ in the inner tank 110 to the circulation unit 140. The circulation unit 140 supplies the processing liquid LQ supplied from the inner tank drainage unit 150 to the drainage unit 160. Alternatively, when discharging the processing liquid LQ from the outer tank 120, the circulation unit 140 supplies the processing liquid LQ in the outer tank 120 to the drainage unit 160. Alternatively, when discharging the processing liquid LQ remaining in the circulation unit 140, the circulation unit 140 supplies the processing liquid LQ remaining in the circulation unit 140 to the drainage unit 160. The drainage unit 160 discharges the processing liquid LQ supplied from the circulation unit 140 to the tank 170. The tank 170 stores the processing liquid LQ discharged through the drainage unit 160. The tank 170 is, for example, a cooling tank that cools the processing liquid LQ discharged through the drainage unit 160.

[0039] The fresh liquid supply unit 180 newly supplies the processing liquid LQ to the inner tank 110 or the outer tank 120. The tank cleaning unit 190 cleans the inner tank 110 and the outer tank 120 with cleaning water. The inner tank level sensor 210 detects the liquid level (liquid surface level) of the processing liquid LQ stored in the inner tank 110 and outputs the detection result to the control unit A1. The outer tank level sensor 220 detects the liquid level (liquid surface level) of the processing liquid LQ stored in the outer tank 120 and outputs the detection result to the control unit A1. The sensor cleaning unit 230 cleans the inner tank level sensor 210 and the outer tank level sensor 220 with a cleaning liquid. The cleaning liquid used by the tank cleaning unit 190 and the sensor cleaning unit 230 is, for example, deionized water, carbonated water, electrolyzed ion water, hydrogen water, ozone water, or hydrochloric acid water with a dilution concentration (for example, about 10 ppm to 100 ppm).

[0040] Specifically, the circulation section 140 further includes a valve 147 and a valve 148. The inner tank liquid discharge section 150 includes an inner tank liquid discharge pipe 151 and a valve 152. The circulation pipe 141 includes a first pipe 141a, a second pipe 141b, and a third pipe 141c. The liquid discharge section 160 includes a liquid discharge pipe 161 and a liquid discharge valve 162. The fresh liquid supply section 180 includes a fresh liquid supply pipe 181, a fresh liquid supply pipe 182, a supply valve 183, a supply valve 184, and a flow meter 186. The tank cleaning section 190 includes a pipe 191, a valve 192, and a flow meter 193. The inner tank level sensor 210 includes a sensor pipe 211, a sensor body 212, a valve 213, and a valve 214. The outer tank level sensor 220 includes a sensor pipe 221, a sensor body 222, a valve 223, and a valve 224. The sensor cleaning section 230 includes a pipe 231, a pipe 232, a valve 233, and a valve 234.

[0041] In the circulation section 140, the circulation pipe 141 extends from inside the outer tank 120 to the circulation liquid introduction member 131 via connection points B1 and B2. The first pipe 141a extends from inside the outer tank 120 to the connection point B1. The second pipe 141b extends from the connection point B1 to the connection point B2. The third pipe 141c extends from the connection point B2 to the circulation liquid introduction member 131. The pump 142 is disposed in the second pipe 141b. That is, the pump 142 is disposed in the circulation pipe 141 upstream of the liquid discharge pipe 161 and the liquid discharge valve 162. The valve 147, the heater 143, the filter 144, the adjustment valve 145 (FIG. 1), and the valve 146 (FIG. 1) are disposed in the third pipe 141c in this order from upstream to downstream.

[0042] Valve 148 is arranged in the first pipe 141a. Valve 148 opens and closes the flow path of the first pipe 141a. When valve 148 opens, the flow path of the first pipe 141a is opened. When valve 148 closes, the flow path of the first pipe 141a is blocked. Valve 147 is arranged between connection point B2 and heater 143. That is, valve 147 is arranged between pump 142 and heater 143 in the circulation pipe 141. Valve 147 opens and closes the flow path of the third pipe 141c. When valve 147 opens, the flow path of the third pipe 141c is opened. When valve 147 closes, the flow path of the third pipe 141c is blocked. By opening valves 147 and 148, closing valve 152 and the drain valve 162, and driving pump 142, the processing liquid LQ in the inner tank 110 circulates through the circulation pipe 141.

[0043] In the circulating liquid introduction part 130, the circulating liquid introduction member 131 extends along the predetermined direction D10. And in each circulating liquid introduction member 131, a plurality of circulating liquid inlets 132 (FIG. 1) are arranged at intervals along the predetermined direction D10.

[0044] In the inner tank drain part 150, one end of the inner tank drain pipe 151 is located inside the inner tank 110, and the other end of the inner tank drain pipe 151 is connected to the circulation pipe 141 at connection point B1. That is, the inner tank drain pipe 151 branches off at connection point B1 of the circulation pipe 141 and extends from connection point B1 to the inside of the inner tank 110. Valve 152 is arranged in the inner tank drain pipe 151. Valve 152 opens and closes the flow path of the inner tank drain pipe 151. When valve 152 opens, the flow path of the inner tank drain pipe 151 is opened. When valve 152 closes, the flow path of the inner tank drain pipe 151 is blocked.

[0045] In the liquid discharge section 160, one end of the liquid discharge pipe 161 is connected to the circulation pipe 141 at the connection point B2. The other end of the liquid discharge pipe 161 is connected to the tank 170. That is, the liquid discharge pipe 161 branches from the circulation pipe 141 at the connection point B2 and extends to the tank 170. Then, the liquid discharge pipe 161 discharges the processing liquid LQ into the tank 170. The liquid discharge valve 162 is arranged in the liquid discharge pipe 161. The liquid discharge valve 162 opens and closes the flow path of the liquid discharge pipe 161. When the liquid discharge valve 162 opens, the flow path of the liquid discharge pipe 161 is opened. When the liquid discharge valve 162 closes, the flow path of the liquid discharge pipe 161 is blocked.

[0046] By opening the liquid discharge valve 162 and the valve 152, closing the valves 147 and 148, and driving the pump 142, the processing liquid LQ in the inner tank 110 is discharged into the tank 170 through the inner tank liquid discharge pipe 151, the second pipe 141b, and the liquid discharge pipe 161. Also, by opening the liquid discharge valve 162 and the valve 148, closing the valves 147 and 152, and driving the pump 142, the processing liquid LQ in the outer tank 120 is discharged into the tank 170 through the first pipe 141a, the second pipe 141b, and the liquid discharge pipe 161.

[0047] In the fresh liquid supply section 180, the fresh liquid supply pipe 181 extends from the tank TA that stores the fresh liquid of the processing liquid LQ to the inside of the inner tank 110. The supply valve 183 is arranged in the fresh liquid supply pipe 181. The supply valve 183 opens and closes the flow path of the fresh liquid supply pipe 181. When the supply valve 183 opens, the flow path of the fresh liquid supply pipe 181 is opened. When the supply valve 183 closes, the flow path of the fresh liquid supply pipe 181 is blocked.

[0048] One end of the fresh liquid supply pipe 182 is connected to the fresh liquid supply pipe 181 at the connection point B3. The other end of the fresh liquid supply pipe 182 is located inside the outer tank 120. The supply valve 184 opens and closes the flow path of the fresh liquid supply pipe 182. When the supply valve 184 opens, the flow path of the fresh liquid supply pipe 182 is opened. When the supply valve 184 closes, the flow path of the fresh liquid supply pipe 182 is blocked.

[0049] By opening the supply valve 183 and closing the supply valve 184, the processing liquid LQ can be supplied to the inner tank 110 through the fresh liquid supply pipe 181. Specifically, the fresh liquid supply pipe 181 has a fresh liquid supply port 185. Then, the fresh liquid supply pipe 181 supplies the processing liquid LQ to the inner tank 110 through the fresh liquid supply port 185. For example, the fresh liquid supply pipe 181 newly supplies the processing liquid LQ to the inner tank 110 through the fresh liquid supply port 185. The fresh liquid supply port 185 is located at the downstream end of the fresh liquid supply pipe 181. The fresh liquid supply port 185 is disposed inside the inner tank 110. The fresh liquid supply port 185, for example, opens vertically downward. However, the orientation of the fresh liquid supply port 185 is not particularly limited. Also, the fresh liquid supply unit 180 may have a plurality of fresh liquid supply pipes 181 or may have a plurality of fresh liquid supply ports 185.

[0050] By opening the supply valve 184 and closing the supply valve 183, the processing liquid LQ can be supplied to the outer tank 120 through the fresh liquid supply pipe 182.

[0051] The flow meter 186 is disposed in the fresh liquid supply pipe 181 upstream of the connection point B3. The flow meter 186 measures the flow rate of the processing liquid LQ flowing through the fresh liquid supply pipe 181 upstream of the connection point B3.

[0052] In the tank cleaning unit 190, the pipe 191 extends from the cleaning water tank TB to the inner tank 110. The valve 192 is disposed in the pipe 191. When the valve 192 opens, the flow path of the pipe 191 is opened, and the cleaning water is supplied to the inner tank 110. When the valve 192 closes, the flow path of the pipe 191 is blocked, and the supply of the cleaning water to the inner tank 110 is stopped. The flow meter 193 is disposed in the pipe 191 upstream of the valve 192. The flow meter 193 measures the flow rate of the processing liquid LQ flowing through the pipe 191.

[0053] In the inner tank level sensor 210, the tip of the sensor tube 211 is immersed in the processing liquid LQ stored in the inner tank 110. Then, the sensor body 212 detects the liquid level of the processing liquid LQ in the inner tank 110 by measuring the air pressure of the nitrogen gas in the sensor tube 211 while supplying nitrogen gas to the sensor tube 211 at a constant flow rate.

[0054] In the outer tank level sensor 220, the tip of the sensor tube 221 is immersed in the processing liquid LQ stored in the outer tank 120. Then, the sensor body 222 measures the air pressure of the nitrogen gas in the sensor tube 221 while supplying nitrogen gas to the sensor tube 221 at a constant flow rate, thereby detecting the liquid level of the processing liquid LQ in the outer tank 120.

[0055] In the sensor cleaning unit 230, one end of the pipe 231 is connected to the cleaning water tank TC, and the other end of the pipe 231 is connected to the sensor tube 211 at the connection point B4. The tank TC may be common to the tank TB. The valve 233 is disposed in the pipe 231. The valve 233 opens and closes the flow path of the pipe 231. When the valve 233 opens, the flow path of the pipe 231 is opened, and the cleaning water is supplied to the sensor tube 211. As a result, the sensor tube 211 is cleaned. When the valve 233 closes, the pipe 231 is blocked, and the supply of the cleaning water to the sensor tube 211 stops.

[0056] One end of the pipe 232 is connected to the pipe 231 at the connection point B6. The other end of the pipe 232 is connected to the sensor tube 221 at the connection point B5. The valve 234 is disposed in the pipe 232. The valve 234 opens and closes the flow path of the pipe 232. When the valve 234 opens, the flow path of the pipe 232 is opened, and the cleaning water is supplied to the sensor tube 221. As a result, the sensor tube 221 is cleaned. When the valve 234 closes, the pipe 232 is blocked, and the supply of the cleaning water to the sensor tube 221 stops.

[0057] The control unit A1 controls the valves 147, 148, 152, 192, 213, 214, 223, 224, 233, 234, the drain valve 162, and the supply valves 183, 184. Further, the control unit A1 controls the pump 142 and the heater 143.

[0058] Next, with reference to FIG. 4, the influence of air entrainment in the processing liquid LQ on the processing of the substrate W will be described. As an example, the dissolved oxygen concentration of the processing liquid LQ will be described. FIG. 4 is a graph showing the relationship between the dissolved oxygen concentration of the processing liquid LQ and the etching amount. The horizontal axis indicates the dissolved oxygen concentration (ppm) of the processing liquid LQ, and the vertical axis indicates the etching amount of the substrate W.

[0059] Also, FIG. 4 shows an example when an aqueous solution of TMAH is used as the alkaline processing liquid LQ. The concentration of TMAH was 0.31%. In the example, a polysilicon film (polysilicon layer) was formed on the substrate W. FIG. 4 shows the etching amount of the polysilicon film when the substrate W was immersed in TMAH. The etching amount is the value obtained by subtracting the thickness of the polysilicon film after immersion from the thickness of the polysilicon film before immersion in TMAH. The etching amount may be described as the "etching amount of the substrate W".

[0060] As shown in FIG. 4, the lower the dissolved oxygen concentration of the processing liquid LQ, the larger the etching amount (processing amount) of the substrate W. The etching amount (processing amount) was approximately directly proportional to the dissolved oxygen concentration. The proportionality constant was "negative".

[0061] As described above with reference to FIG. 4, for example, when the processing liquid LQ is alkaline, the processing amount of the substrate W is affected by the dissolved oxygen concentration of the processing liquid LQ. Therefore, when processing the substrate W, it is preferable that the dissolved oxygen concentration of the processing liquid LQ is lower.

[0062] That is, for example, when the processing liquid LQ is alkaline, air entrainment in the processing liquid LQ affects the processing of the substrate W. This is because air contains oxygen. Therefore, when processing the substrate W, it is preferable that less air is entrained in the processing liquid LQ.

[0063] Next, with reference to FIGS. 1 and 5 to 8, the substrate processing method according to this embodiment will be described. As shown in FIG. 1, in the substrate processing method, the substrate W is processed with the processing liquid LQ in the inner tank 110. Further, in the substrate processing method, the processing liquid LQ is introduced into the inner tank 110 through the circulation pipe 141 and the circulation liquid inlet 132 from the outer tank 120 into which the processing liquid LQ that has overflowed from the inner tank 110 storing the processing liquid LQ flows, so that the processing liquid LQ stored in the inner tank 110 can be circulated.

[0064] The substrate processing method includes a processing liquid exchange method. FIGS. 5 to 8 are schematic diagrams showing the processing liquid exchange method. As shown in FIGS. 5 to 8, the processing liquid exchange method includes steps S1 to S4. The processing liquid exchange method is executed after the lifetime of the processing liquid LQ has expired. The lifetime is the usage time at which it is determined that if the state of the processing liquid LQ changes and the use of the processing liquid LQ is continued, the processing itself cannot be sufficiently performed. That is, the lifetime is the usage time at which the processing performance of the processing liquid LQ cannot be maintained due to continuous use of the processing liquid LQ. The lifetime is determined experimentally and / or empirically.

[0065] Hereinafter, the processing liquid LQ whose lifetime has expired may be described as "used processing liquid LQ" or "old liquid". Also, the processing liquid LQ newly supplied in place of the processing liquid LQ whose lifetime has expired may be described as "unused processing liquid LQ" or "new liquid".

[0066] First, as shown in FIG. 5, in step S1, the processing liquid LQ is discharged from the inner tank 110, the outer tank 120, and the circulation pipe 141 to the tank 170. As a result, the inner tank 110, the outer tank 120, and the circulation pipe 141 become empty. The processing liquid LQ discharged in step S1 is, for example, the processing liquid whose lifetime has expired. Step S1 corresponds to an example of the "first drainage step" of the present invention.

[0067] In FIG. 5, the state ST11 indicates the state during the discharge of the processing liquid LQ. The state ST12 indicates the state in which the inner tank 110, the outer tank 120, and the circulation pipe 141 have become empty.

[0068] As an example, first, the processing liquid LQ in the inner tank 110 is discharged by the inner tank drain pipe 151, the second pipe 141b, and the drain pipe 161. Next, the processing liquid LQ in the outer tank 120 is discharged by the first pipe 141a, the second pipe 141b, and the drain pipe 161. Next, the processing liquid LQ is discharged from the circulation pipe 141 (the first pipe 141a to the third pipe section 25c).

[0069] Specifically, in step S1, the control unit A1 controls the drain valve 162, the valve 147, the valve 148, the valve 152, and the pump 142 so as to discharge the processing liquid LQ from the inner tank 110, the outer tank 120, and the circulation pipe 141 to the tank 170. In this case, the drain valve 162 is opened, the valve 147 and the supply valve 183 are closed, and the pump 142 is driven. When discharging the processing liquid LQ from the outer tank 120, the valve 148 is opened and the valve 152 is closed. When discharging the processing liquid LQ from the inner tank 110, the valve 152 is opened and the valve 148 is closed. Details of the control will be described later.

[0070] Next, as shown in FIG. 6, in step S2, by newly supplying the processing liquid LQ to the inner tank 110, the processing liquid LQ is newly stored in the inner tank 110. That is, after discharging the processing liquid LQ from the inner tank 110, the outer tank 120, and the circulation pipe 141 (after discharging the processing liquid LQ in step S1), by newly supplying the processing liquid LQ to the inner tank 110 through the new liquid supply pipe 181 and the new liquid supply port 185, the processing liquid LQ is newly stored in the inner tank 110. When the inner tank 110 is full of the processing liquid LQ, the processing liquid LQ overflows from the inner tank 110 and flows into the outer tank 120. As a result, the processing liquid LQ is stored not only in the inner tank 110 but also in the outer tank 120. Step S2 corresponds to an example of the "first supply step" of the present invention.

[0071] In FIG. 6, the state ST21 indicates a state in which the processing liquid LQ is being newly supplied to the inner tank 110. The state ST22 indicates a state in which the liquid level of the processing liquid LQ in the inner tank 110 reaches the inner tank fixed level LVI and the liquid level of the processing liquid LQ in the outer tank 120 reaches the outer tank fixed level LVO.

[0072] The inner tank quantitative level LVI indicates the liquid level at which the inner tank 110 is filled with the processing liquid LQ. That is, the inner tank quantitative level LVI indicates the upper limit of the liquid level of the processing liquid LQ to be stored in the inner tank 110. The inner tank quantitative level LVI corresponds to an example of the "inner tank upper limit level" of the present invention.

[0073] The outer tank quantitative level LVO indicates the liquid level corresponding to the storage amount of the processing liquid LQ in the outer tank 120 required to circulate the processing liquid LQ. That is, the outer tank quantitative level LVO indicates the upper limit of the liquid level of the processing liquid LQ to be stored in the outer tank 120. In this regard, the outer tank quantitative level LVO can also be described as the outer tank upper limit level. The outer tank quantitative level LVO is lower than the full level of the outer tank quantitative level LVO. The outer tank quantitative level LVO is determined experimentally and / or empirically.

[0074] Specifically, in step S 2, the control unit A1 controls the supply valve 183 so as to supply the processing liquid LQ newly to the inner tank 110 after discharging the processing liquid LQ from the inner tank 110, the outer tank 120, and the circulation pipe 141. Therefore, the processing liquid LQ is newly supplied from the new liquid supply pipe 181 to the inner tank 110. In this case, the supply valve 183 is opened, the valves 147, 148, 152, and the drain valve 162 are closed, and the pump 142 is stopped. Details of the control will be described later.

[0075] Further, when the inner tank 110 and the outer tank 120 are in the state ST 22, the control unit A1 controls the valve 147, the valve 148, the valve 152, the drain valve 162, and the pump 142 so that the processing liquid LQ in the inner tank 110 circulates through the circulation pipe 141. In this case, the valves 147 and 148 are opened, the valve 152, the supply valve 183, and the drain valve 162 are closed, and the pump 142 is driven. Details of the control will be described later.

[0076] Next, as shown in FIG. 7, in step S3, the processing liquid LQ stored in the inner tank 110 is discharged into the tank 170 until the lower limit level LVL of the inner tank. That is, after newly supplying the processing liquid LQ to the inner tank 110 (after step S2), the processing liquid LQ stored in the inner tank 110 is discharged into the tank 170 until the lower limit level LVL of the inner tank. In this case, the processing liquid LQ in the inner tank 110 is discharged into the tank 170 through the inner tank drain pipe 151, the second pipe 141b, and the drain pipe 161. On the other hand, in the present embodiment, the processing liquid LQ in the outer tank 120 is not discharged. Step S3 corresponds to an example of the "second drainage step" of the present invention.

[0077] In FIG. 7, the state ST31 indicates a state in the middle of discharging the processing liquid LQ from the inner tank 110. The state ST32 indicates a state in which the processing liquid LQ has been discharged from the inner tank 110 to the lower limit level LVL of the inner tank.

[0078] The lower limit level LVL of the inner tank indicates a liquid level higher than the position of the circulating liquid inlet 132 (FIG. 1) arranged inside the inner tank 110 and also indicates a liquid level higher than the position of the fresh liquid supply port 185 arranged inside the inner tank 110. Therefore, when the liquid level of the processing liquid LQ is at the lower limit level LVL of the inner tank, the fresh liquid supply port 185 and the circulating liquid inlet 132 (FIG. 1) of the circulating liquid introduction member 131 are located in the processing liquid LQ and are not exposed to the outside from the processing liquid LQ. Note that the inner tank fixed level LVI indicates a liquid level higher than the lower limit level LVL in the inner tank 110.

[0079] Specifically, in step S3, the control unit A1 controls the drain valve 162, the valve 147, the valve 148, the valve 152, and the pump 142 so that after newly supplying the processing liquid LQ to the inner tank 110, the processing liquid LQ stored in the inner tank 110 is discharged until the lower limit level LVL of the inner tank. In this case, the drain valve 162 and the valve 152 are open, the valves 147, 148, and the supply valve 183 are closed, and the pump 142 is driven. Details of the control will be described later.

[0080] In the case where there are a plurality of fresh liquid supply ports 185, the lower limit level LVL of the inner tank indicates a liquid level higher than the position of the circulating liquid inlet 132 (FIG. 1) and higher than the position of the uppermost fresh liquid supply port 185. Further, in the case where there are a plurality of circulating liquid inlets 132, the lower limit level LVL of the inner tank indicates a liquid level higher than the position of the uppermost circulating liquid inlet 132 (FIG. 1) and higher than the position of the fresh liquid supply port 185. Furthermore, in the case where there are a plurality of fresh liquid supply ports 185 and a plurality of circulating liquid inlets 132, the lower limit level LVL of the inner tank indicates a liquid level higher than the position of the uppermost circulating liquid inlet 132 (FIG. 1) and higher than the position of the uppermost fresh liquid supply port 185.

[0081] Next, as shown in FIG. 8, in step S4, by newly supplying the treatment liquid LQ to the inner tank 110, the treatment liquid LQ is newly stored in the inner tank 110. That is, after discharging the treatment liquid LQ from the inner tank 110 to the lower limit level LVL of the inner tank (after step S3), the treatment liquid LQ is newly supplied to the inner tank 110 through the fresh liquid supply pipe 181 and the fresh liquid supply port 185, thereby newly storing the treatment liquid LQ in the inner tank 110. Step S4 corresponds to an example of the "second supply step" of the present invention.

[0082] In FIG. 8, the state ST41 indicates a state in which the treatment liquid LQ is being newly supplied to the inner tank 110. The state ST42 indicates a state in which the liquid level of the treatment liquid LQ in the inner tank 110 reaches the inner tank fixed level LVI and the liquid level of the treatment liquid LQ in the outer tank 120 reaches the outer tank fixed level LVO.

[0083] Specifically, in step S4, the control unit A1 controls the supply valve 183 so as to newly supply the treatment liquid LQ to the inner tank 110 after discharging the treatment liquid LQ from the inner tank 110 to the lower limit level LVL of the inner tank. Therefore, the treatment liquid LQ is newly supplied from the fresh liquid supply pipe 181 to the inner tank 110. In this case, the supply valve 183 is opened, the valves 147, 148, 152, and the drain valve 162 are closed, and the pump 142 is stopped. Details of the control will be described later.

[0084] Further, when the inner tank 110 and the outer tank 120 reach the state ST42, the control unit A1 controls the valve 147, the valve 148, the valve 152, the drain valve 162, and the pump 142 so that the processing liquid LQ in the inner tank 110 circulates through the circulation pipe 141. In this case, the valves 147 and 148 are open, the valves 152, the supply valve 183, and the drain valve 162 are closed, and the pump 142 is driven. Details of the control will be described later.

[0085] As described above with reference to FIGS. 5 to 8, according to the present embodiment, the old liquid is replaced with the new liquid in steps S1 and S2. That is, in steps S1 and S2, the total liquid exchange of the processing liquid LQ is performed in the inner tank 110 and the outer tank 120.

[0086] After the total liquid exchange of the processing liquid LQ, in step S3, the processing liquid LQ is discharged to the lower limit level LVL of the inner tank, and in step S4, the new processing liquid LQ is newly supplied to the inner tank 110. In particular, in step S3, the new liquid supply port 185 and the circulating liquid introduction port 132 are located below the liquid level of the processing liquid LQ. Therefore, it is possible to suppress the entry of air from the new liquid supply port 185 into the new liquid supply pipe 181 and the entry of air from the circulating liquid introduction port 132 (FIG. 1) into the circulating liquid introduction member 131.

[0087] As a result, in step S4, it is possible to newly supply the processing liquid LQ to the inner tank 110 while suppressing the entry of air into the new liquid supply pipe 181 and the circulating liquid introduction member 131. In addition, in step S3, while suppressing the entry of air into the new liquid supply pipe 181 and the circulating liquid introduction member 131, it is possible to discharge the processing liquid LQ mixed with air in step S2 and discharge the air remaining in the circulation pipe 141. As a result, it is possible to suppress the entry of air into the processing liquid LQ. Therefore, the processing of the substrate W can be effectively performed.

[0088] For example, the ability to suppress air from mixing into the processing liquid LQ corresponds to the ability to suppress oxygen from dissolving in the processing liquid LQ. Therefore, if air can be prevented from mixing into the processing liquid LQ, the dissolved oxygen concentration of the processing liquid LQ can be reduced. As a result, it is possible to suppress a decrease in the processing amount (etching amount) of the substrate W due to dissolved oxygen (Fig. 4). This is particularly effective when the processing liquid LQ is alkaline.

[0089] Also, in the present embodiment, in step S3, the control unit A1 closes the valve 148. Therefore, in step S3, the control unit A1 does not discharge the processing liquid LQ stored in the outer tank 120. Therefore, the inlet 141x of the circulation pipe 141 is located below the liquid level of the processing liquid LQ in the outer tank 120. That is, the inlet 141x of the circulation pipe 141 is located in the processing liquid LQ in the outer tank 120 and is not exposed to the outside of the processing liquid LQ. Therefore, it is possible to suppress air from entering the circulation pipe 141 from the inlet 141x. As a result, it is possible to further suppress air from mixing into the processing liquid LQ.

[0090] Furthermore, in the present embodiment, when the processing liquid LQ in the inner tank 110 is discharged to the inner tank lower limit level LVL in step S3, the control unit A1 stops the pump 142 that is operating. Therefore, it is possible to reliably suppress the liquid level of the processing liquid LQ from dropping below the inner tank lower limit level LVL. Also, when the processing liquid LQ is supplied to at least the inner tank fixed amount level LVI in step S4, the control unit A1 drives the pump 142 to circulate the processing liquid LQ in the inner tank 110 through the circulation pipe 141. Therefore, the air remaining in the circulation pipe 141 can be discharged. As an example, in the present embodiment, when the liquid level of the processing liquid LQ in the inner tank 110 reaches the inner tank fixed amount level LVI and the liquid level of the processing liquid LQ in the outer tank 120 reaches the outer tank fixed amount level LVO, the control unit A1 drives the pump 142.

[0091] Furthermore, in the present embodiment, step S3 and step S4 may be each executed once, or step S3 and step S4 may be each executed a plurality of times. When step S3 and step S4 are each executed a plurality of times, while suppressing the entry of air into the fresh liquid supply pipe 181 and the circulating liquid introduction member 131, the treatment liquid LQ mixed with air can be more effectively discharged, and the air remaining in the circulation pipe 141 can be more effectively discharged. Therefore, the entry of air into the treatment liquid LQ can be more effectively suppressed.

[0092] Here, the number of executions of each of step S3 and step S4 is described as "N". That is, when step S3 and step S4 are regarded as one set, N sets are executed. "N" represents an integer of 1 or more.

[0093] For example, when the volume of the treatment liquid LQ at the inner tank fixed level LVI is "V1", the volume of the treatment liquid LQ at the outer tank fixed level LVO is "V2", the capacity of the circulation pipe 141 is "V3", and the volume of the treatment liquid LQ discharged from the inner tank 110 in step S3 is "V4", "N" is determined by the following formula. Specifically, the volume V4 represents the volume of the treatment liquid LQ from the inner tank fixed level LVI to the inner tank lower limit level LVL. When "N" in the following formula has a decimal point, the value obtained by rounding up the decimal part or the value obtained by rounding down the decimal part may be set as the number of executions N.

[0094] N = (V1 + V2 + V3) / V4

[0095] According to this example, in the state ST22 (FIG. 6) in step S2, all of the "treatment liquid LQ mixed with air" present in the inner tank 110, the outer tank 120, and the circulation pipe 141 can be replaced with a new treatment liquid LQ in which the entry of air is suppressed.

[0096] Further, in the present embodiment, the control unit A1 may acquire information indicating the dissolved oxygen concentration of the treatment liquid LQ from the dissolved oxygen meter 240 (FIG. 3). Then, the control unit A1 may determine the respective number of executions N of step S3 and step S4 according to the dissolved oxygen concentration in the treatment liquid LQ stored in the inner tank 110. In this case, according to the dissolved oxygen concentration of the treatment liquid LQ, the respective number of executions N of step S3 and step S4 can be optimized. For example, the higher the dissolved oxygen concentration of the treatment liquid LQ, the greater the respective number of executions N of step S3 and step S4. The respective number of executions N of step S3 and step S4 may be 1 time or 2 times or more.

[0097] Next, with reference to FIG. 9, a treatment liquid replacement method will be described. FIG. 9 is a time chart showing the replacement sequence of the treatment liquid LQ in the treatment liquid replacement method according to the present embodiment. The horizontal axis indicates time. Further, FIG. 9 illustrates the case where the number of executions N = 2. Steps S1 to S4 in FIG. 9 respectively show steps S1 to S4 in FIGS. 5 to 8.

[0098] As shown in FIG. 9, step S1 (first drainage step) is started at time t1 and step S1 ends at time t2. Also, step S2 (first supply step) is started at time t2 and step S2 ends at time t3. Further, the first time step S3 (second drainage step) is started at time t4 and the first time step S3 ends at time t5. Further, the first time step S4 (second supply step) is started at time t5 and the first time step S4 ends at time t6. Further, the second time step S3 (second drainage step) is started at time t7 and the second time step S3 ends at time t8. Further, the second time step S4 (second supply step) is started at time t8 and the second time step S4 ends at time t9.

[0099] Note that in FIG. 9, the liquid replacement of steps S1 and S2 is described as "total liquid replacement". Also, the liquid replacement of steps S3 and S4 is described as "partial liquid replacement".

[0100] Next, with reference to FIGS. 2, 3, 10 to 12, the details of the substrate processing method according to the present embodiment will be described. FIG. 10 is a flowchart showing the substrate processing method according to the present embodiment.

[0101] As shown in FIG. 10, the substrate processing method includes steps S11 to S21. The substrate processing method is executed by the substrate processing apparatus 100.

[0102] As shown in FIGS. 2 and 10, first, in step S11, the control unit A1 controls the substrate holding unit 125 so as to immerse the substrate W in the processing liquid LQ in the inner tank 110. As a result, the substrate holding unit 125 lowers the substrate W and immerses the substrate W in the processing liquid LQ.

[0103] Next, in step S12, in the inner tank 110, the substrate W is processed by the processing liquid LQ.

[0104] Next, in step S13, the control unit A1 controls the substrate holding unit 125 so as to lift the substrate W from the processing liquid LQ in the inner tank 110. As a result, the substrate holding unit 125 raises the substrate W and lifts the substrate W from the processing liquid LQ.

[0105] Next, in step S14, the control unit A1 determines whether the replacement time of the processing liquid LQ has arrived. That is, the control unit A1 determines whether the lifetime of the processing liquid LQ has expired.

[0106] If it is determined in step S14 that the replacement time of the processing liquid LQ has not arrived (No), the process returns to step S11.

[0107] On the other hand, if it is determined in step S14 that the replacement time of the processing liquid LQ has arrived (Yes), the process proceeds to step S15. In this case, the process proceeds to step S15 on the condition that the tank 170 is empty.

[0108] Next, as shown in FIGS. 3 and 10, in step S15, the control unit A1 empties the outer tank 120 by discharging the processing liquid LQ from the outer tank 120 to the tank 170. Specifically, the control unit A1 opens the drain valve 162 and the valve 148, and closes the valves 147 and 152. In addition, the control unit A1 drives the pump 142. As a result, the processing liquid LQ is discharged from the outer tank 120 to the tank 170, and the outer tank 120 becomes empty. Specifically, the processing liquid LQ is discharged from the outer tank 120 to the tank 170 through the first pipe 141a, the second pipe 141b, and the drain pipe 161. In step S15, the control unit A1 closes the valves 192, 233, 235 and the supply valves 183, 184.

[0109] Next, in step S16, the control unit A1 empties the inner tank 110 by discharging the processing liquid LQ from the inner tank 110 to the tank 170. Specifically, the control unit A1 opens the drain valve 162 and the valve 152, and closes the valves 147 and 148. Also, the control unit A1 continues to drive the pump 142. As a result, the processing liquid LQ is discharged from the inner tank 110 to the tank 170, and the inner tank 110 becomes empty. Specifically, the processing liquid LQ is discharged from the inner tank 110 to the tank 170 through the inner tank drain pipe 151, the second pipe 141b, and the drain pipe 161. In step S16, the control unit A1 closes the valves 192, 233, 235 and the supply valves 183, 184.

[0110] Next, in step S17, the control unit A1 empties the circulation pipe 141 by discharging the processing liquid LQ from the circulation pipe 141 to the tank 170. Specifically, the control unit A1 opens the drain valve 162 and the valves 147 and 148. In addition, the control unit A1 stops the pump 142. As a result, the processing liquid LQ is discharged from the circulation pipe 141 to the tank 170 by the self-weight of the processing liquid LQ, and the circulation pipe 141 becomes empty. In step S17, the control unit A1 closes the valves 152, 192, 233, 235 and the supply valves 183, 184.

[0111] Next, in step S18, the control unit A1 cleans the inner tank level sensor 210 and the outer tank level sensor 220 with cleaning water. Specifically, the control unit A1 opens valves 233 and 235 to clean the sensor tubes 211 and 221. After cleaning, the control unit A1 closes valves 233 and 235. Details are omitted. In FIG. 10, for simplicity of the drawing, the process corresponding to step S18 is omitted.

[0112] Next, in step S19, the control unit A1 cleans the inner tank 110 and the outer tank 120 with cleaning water. Specifically, the control unit A1 opens valve 192 to clean the inner tank 110 and the outer tank 120. After cleaning, the control unit A1 closes valve 192. Details are omitted. In FIG. 10, for simplicity of the drawing, the process corresponding to step S19 is omitted.

[0113] Next, in step S20, the control unit A1 newly stores the processing liquid LQ in the inner tank 110 and the outer tank 120. That is, the control unit A1 replaces the old liquid in the inner tank 110 and the outer tank 120 with new liquid. Details will be described later.

[0114] Next, in step S21, the control unit A1 adjusts the temperature of the processing liquid LQ to the target value. Specifically, the control unit A1 controls the heater 143 to adjust the temperature of the processing liquid LQ to the target value. After step S21, the process proceeds to step S11.

[0115] Note that steps S14 to S20 implement the processing liquid replacement method according to this embodiment.

[0116] FIGS. 11 and 12 are flowcharts showing the details of step S20 in FIG. 10. As shown in FIGS. 11 and 12, step S20 in FIG. 10 includes steps S201 to S214.

[0117] First, as shown in FIGS. 3 and 11, in step S201, the control unit A1 starts to newly supply the treatment liquid LQ to the inner tank 110. Specifically, the control unit A1 opens the supply valve 183 and closes the drain valve 162, valves 147, 148, 152, 192, 233, 235, and the supply valve 184 to start newly supplying the treatment liquid LQ to the inner tank 110. Specifically, the treatment liquid LQ is supplied to the inner tank 110 from the fresh liquid supply pipe 181 and the fresh liquid supply port 185. When the inner tank 110 is full of the treatment liquid LQ, the treatment liquid LQ overflows from the inner tank 110 and flows into the outer tank 120.

[0118] Next, in step S202, the control unit A1 determines whether or not the liquid level of the treatment liquid LQ stored in the outer tank 120 has reached the outer tank fixed level LVO (FIG. 6) based on the detection result of the outer tank level sensor 220.

[0119] If it is determined in step S202 that the liquid level of the treatment liquid LQ has not reached the outer tank fixed level LVO (No), the process of step S202 is repeated until the liquid level of the treatment liquid LQ reaches the outer tank fixed level LVO.

[0120] On the other hand, if it is determined in step S202 that the liquid level of the treatment liquid LQ has reached the outer tank fixed level LVO (Yes), the process proceeds to step S203.

[0121] Next, in step S203, the control unit A drives the pump 142. In this case, the control unit A1 opens the valves 147 and 148. As a result, the treatment liquid LQ in the inner tank 110 circulates through the circulation pipe 141.

[0122] Next, in step S204, the control unit A1 determines whether or not the liquid level of the treatment liquid LQ in the outer tank 120 has stabilized at the outer tank fixed level LVO based on the detection result of the outer tank level sensor 220. Specifically, the control unit A1 determines that the liquid level of the treatment liquid LQ has stabilized at the outer tank fixed level LVO when the liquid level of the treatment liquid LQ in the outer tank 120 continues at the outer tank fixed level LVO for a predetermined period.

[0123] When it is determined in step S204 that the liquid level of the processing liquid LQ is not stable at the outer tank fixed level LVO (No), the process of step S204 is repeated until the liquid level of the processing liquid LQ becomes stable at the outer tank fixed level LVO. For example, when the liquid level in the outer tank 120 drops due to the driving of the pump 142 (circulation of the processing liquid LQ) in step S203, the control unit A1 replenishes the processing liquid LQ into the outer tank 120 via the inner tank 110 from the fresh liquid supply pipe 181 and the fresh liquid supply port 185, and adjusts the liquid level in the outer tank 120 to be stable at the outer tank fixed level LVO.

[0124] On the other hand, when it is determined in step S204 that the liquid level of the processing liquid LQ is stable at the outer tank fixed level LVO (Yes), the process proceeds to step S205.

[0125] Next, in step S205, the control unit A1 stops the supply of the processing liquid LQ to the inner tank 110. Specifically, the control unit A1 closes the supply valve 183 to stop the supply of the processing liquid LQ to the inner tank 110.

[0126] Next, in step S206, the control unit A1 starts discharging the processing liquid LQ from the inner tank 110 to the tank 170 on the condition that the free capacity of the tank 170 is equal to or greater than the capacity capable of accommodating the drained liquid. That is, the discharge of the processing liquid LQ from the inner tank 110 is started on the condition that the free capacity of the tank 170 is equal to or greater than the capacity capable of accommodating the processing liquid LQ from the inner tank fixed level LVI to the inner tank lower limit level LVL. Specifically, the control unit A1 closes the valves 147 and 148, and opens the drain valve 162 and the valve 152 to start discharging the processing liquid LQ from the inner tank 110 to the tank 170. In this case, the processing liquid LQ is discharged from the inner tank 110 to the tank 170 through the inner tank drain pipe 151, the second pipe 141b, and the drain pipe 161. Also, since the valve 147 is closed, the circulation of the processing liquid LQ stops.

[0127] Next, in step S207, the control unit A1 determines whether or not the liquid level of the processing liquid LQ in the inner tank 110 has reached the inner tank lower limit level LVL based on the detection result of the inner tank level sensor 210.

[0128] When it is determined in step S207 that the liquid level of the processing liquid LQ has not reached the lower limit level LVL of the inner tank (No), the process of step S207 is repeated until the liquid level of the processing liquid LQ reaches the lower limit level LVL of the inner tank. That is, the discharge of the processing liquid LQ from the inner tank 110 is continued until the liquid level of the processing liquid LQ reaches the lower limit level LVL of the inner tank.

[0129] On the other hand, when it is determined in step S207 that the liquid level of the processing liquid LQ has reached the lower limit level LVL of the inner tank (Yes), the process proceeds to step S208.

[0130] Next, in step S208, the control unit A1 stops the pump 142. As a result, the discharge of the processing liquid LQ from the inner tank 110 to the tank 170 is stopped. Further, the control unit A1 closes the drain valve 162 and the valve 152.

[0131] Next, in step S209, the control unit A1 starts to newly supply the processing liquid LQ to the inner tank 110. Specifically, the control unit A1 starts to newly supply the processing liquid LQ to the inner tank 110 by opening the supply valve 183. Specifically, the processing liquid LQ is supplied to the inner tank 110 from the new liquid supply pipe 181 and the new liquid supply port 185.

[0132] Next, as shown in FIGS. 3 and 12, in step S210, the control unit A1 determines whether or not the liquid level of the processing liquid LQ stored in the inner tank 110 has reached the inner tank fixed amount level LVI (FIG. 8) based on the detection result of the inner tank level sensor 210. In addition, the control unit A1 determines whether or not the liquid level of the processing liquid LQ stored in the outer tank 120 has reached the outer tank fixed amount level LVO (FIG. 8) based on the detection result of the outer tank level sensor 220.

[0133] If it is determined in step S210 that the liquid level of the processing liquid LQ in the inner tank 110 has not reached the inner tank fixed level LVI (No), or if it is determined in step S210 that the liquid level of the processing liquid LQ in the outer tank 120 has not reached the outer tank fixed level LVO (No), the process of step S210 is repeated until the liquid level of the processing liquid LQ in the inner tank 110 reaches the inner tank fixed level LVI and the liquid level of the processing liquid LQ in the outer tank 120 reaches the outer tank fixed level LVO.

[0134] On the other hand, if it is determined in step S210 that the liquid level of the processing liquid LQ in the inner tank 110 has reached the inner tank fixed level LVI and it is determined in step S210 that the liquid level of the processing liquid LQ in the outer tank 120 has reached the outer tank fixed level LVO (Yes), the process proceeds to step S211.

[0135] Next, in step S211, the control unit A1 drives the pump 142. In this case, the control unit A1 opens the valves 147 and 148. As a result, the processing liquid LQ in the inner tank 110 circulates through the circulation pipe 141.

[0136] Next, in step S212, the control unit A1 determines whether or not the liquid level of the processing liquid LQ in the inner tank 110 has stabilized at the inner tank fixed level LVI based on the detection result of the inner tank level sensor 210. Specifically, the control unit A1 determines that the liquid level of the processing liquid LQ has stabilized at the inner tank fixed level LVI when the liquid level of the processing liquid LQ in the inner tank 110 has continued at the inner tank fixed level LVI for a predetermined period.

[0137] If it is determined in step S212 that the liquid level of the processing liquid LQ has not stabilized at the inner tank fixed level LVI (No), the process of step S212 is repeated until the liquid level of the processing liquid LQ stabilizes at the inner tank fixed level LVI.

[0138] On the other hand, if it is determined in step S212 that the liquid level of the processing liquid LQ has stabilized at the inner tank fixed level LVI (Yes), the process proceeds to step S213.

[0139] Next, in step S213, the control unit A1 stops the supply of the processing liquid LQ to the inner tank 110. Specifically, the control unit A1 closes the supply valve 183 to stop the supply of the processing liquid LQ to the inner tank 110.

[0140] Next, in step S214, the control unit A1 determines whether steps S206 to S213 have been executed M times. M represents an integer of 1 or more. For example, M is determined experimentally and / or empirically. FIG. 10 shows the case where M = 2.

[0141] If it is determined in step S214 that steps S206 to S213 have not been executed M times (No), the process proceeds to step S206.

[0142] On the other hand, if it is determined in step S214 that steps S206 to S213 have been executed M times (Yes), the process proceeds to step S21 in FIG. 10.

[0143] As described above with reference to FIGS. 10 to 12, according to the substrate processing method according to the present embodiment, after the total liquid exchange of the processing liquid LQ in steps S15 to S19, the processing liquid LQ is discharged to the inner tank lower limit level LVL in steps S206 and S207, and a new processing liquid LQ is supplied to the inner tank 110 in step S209. In particular, in steps S206 and S207, the fresh liquid supply port 185 and the circulating liquid inlet 132 are located below the liquid level of the processing liquid LQ. Therefore, it is possible to suppress air from entering the fresh liquid supply pipe 181 from the fresh liquid supply port 185 and air from entering the circulating liquid introduction member 131 from the circulating liquid inlet 132 (FIG. 1).

[0144] As a result, in step S209, while suppressing air from entering the fresh liquid supply pipe 181 and the circulating liquid introduction member 131, the inner tank 110 can be newly supplied with the processing liquid LQ. In addition, in steps S206 and S207, while suppressing air from entering the fresh liquid supply pipe 181 and the circulating liquid introduction member 131, the processing liquid LQ mixed with air in steps S201 to S205 can be discharged, and the air remaining in the circulation pipe 141 can be discharged. As a result, air can be prevented from mixing into the processing liquid LQ. Therefore, the processing of the substrate W can be effectively executed.

[0145] Here, steps S15 to S17 in FIG. 10 correspond to an example of the "first drainage step" of the present invention. Further, steps S201 to S205 in FIG. 11 correspond to an example of the "first supply step" of the present invention. Furthermore, steps S206 to S208 in FIG. 11 correspond to an example of the "second drainage step" of the present invention. Furthermore, steps S209 to S213 in FIGS. 11 and 12 correspond to an example of the "second supply step" of the present invention.

[0146] In steps S3 in FIG. 7 and S206 in FIG. 11, the processing liquid LQ was discharged only from the inner tank 110, and not from the outer tank 120. However, in steps S3 in FIG. 7 and S206 in FIG. 11, as long as the inlet 141x (FIG. 3) of the circulation pipe 141 is located in the processing liquid LQ and not exposed to the outside of the processing liquid LQ, in addition to the inner tank 110, the processing liquid LQ may also be discharged from the outer tank 120. In this case, the discharge time of the processing liquid LQ can be shortened.

[0147] The embodiments of the present invention have been described above with reference to the drawings. However, the present invention is not limited to the above embodiments, and can be implemented in various forms without departing from the gist thereof. In addition, the plurality of components disclosed in the above embodiments can be modified as appropriate. For example, a component among all the components shown in a certain embodiment may be added to the components of another embodiment, or some of the components among all the components shown in a certain embodiment may be deleted from the embodiment.

[0148] Also, for the purpose of facilitating the understanding of the invention, the drawings schematically show each component mainly, and the thickness, length, number, interval, etc. of each illustrated component may be different from the actual ones for the convenience of drawing creation. Also, the configurations of each component shown in the above embodiments are merely examples and are not particularly limited. Needless to say, various changes can be made without substantially departing from the effects of the present invention.

Industrial Applicability

[0149] The present invention relates to a substrate processing method and a substrate processing apparatus and has industrial applicability.

Explanation of Reference Numerals

[0150] 100 Substrate processing apparatus 110 Inner tank 120 Outer tank 131 Circulating liquid introduction member 132 Circulating liquid inlet 141 Circulation pipe 142 Pump 161 Drain pipe 162 Drain valve 181 Fresh liquid supply pipe 183 Supply valve A1 Control unit LVI Inner tank fixed quantity level (inner tank upper limit level) LVL Inner tank lower limit level LVO Outer tank fixed quantity level (outer tank upper limit level) W Substrate

Claims

1. A substrate processing method for circulating the processing liquid stored in an inner tank by introducing the processing liquid that has overflowed from the inner tank storing the processing liquid into the inner tank through a circulation pipe and a circulation liquid inlet, and processing a substrate with the processing liquid in the inner tank, comprising: a first liquid discharge step of discharging the processing liquid from the inner tank, the outer tank, and the circulation pipe; a first supply step of newly storing the processing liquid in the inner tank by newly supplying the processing liquid to the inner tank through a fresh liquid supply port after discharging the processing liquid in the first liquid discharge step; a second liquid discharge step of discharging the processing liquid stored in the inner tank to the lower limit level of the inner tank after newly supplying the processing liquid to the inner tank; a second supply step of newly storing the processing liquid in the inner tank by newly supplying the processing liquid to the inner tank through the fresh liquid supply port after discharging the processing liquid to the lower limit level of the inner tank; and the lower limit level of the inner tank indicates a liquid level higher than the position of the circulation liquid inlet disposed inside the inner tank and higher than the position of the fresh liquid supply port disposed inside the inner tank. A substrate processing method.

2. The substrate processing method according to claim 1, wherein the second liquid discharge step and the second supply step are each executed a plurality of times.

3. The substrate processing method according to claim 1 or claim 2, wherein the number of executions of the second liquid discharge step and the second supply step is determined according to the dissolved oxygen concentration in the processing liquid stored in the inner tank.

4. The substrate processing method according to any one of claims 1 to 3, wherein in the second liquid discharge step, the processing liquid stored in the outer tank is not discharged.

5. When the processing liquid in the inner tank is discharged to the lower limit level of the inner tank in the second liquid discharge step, stop the pump in operation; When the processing liquid is supplied to at least the upper limit level of the inner tank in the second supply step, drive the pump to circulate the processing liquid in the inner tank through the circulation pipe; The upper limit level of the inner tank indicates a liquid level higher than the lower limit level of the inner tank in the inner tank. The substrate processing method according to any one of claims 1 to 4.

6. The substrate processing method according to any one of claims 1 to 5, wherein the processing liquid is alkaline.

7. an inner tank for storing a processing liquid; An outer tank disposed outside the inner tank, into which the processing liquid overflowing from the inner tank flows; A circulating liquid introduction member having a circulating liquid inlet, and introducing the processing liquid supplied from the outer tank through the circulating liquid inlet into the inner tank; A circulation pipe for circulating the processing liquid stored in the inner tank by supplying the processing liquid from the outer tank to the circulating liquid introduction member; A drain pipe branched from the circulation pipe for discharging the processing liquid; A drain valve for opening and closing the flow path of the drain pipe; A pump disposed in the circulation pipe upstream of the drain pipe for sending out the processing liquid in the circulation pipe; A fresh liquid supply pipe having a fresh liquid supply port for newly supplying the processing liquid into the inner tank through the fresh liquid supply port; A supply valve for opening and closing the flow path of the fresh liquid supply pipe; A control unit for controlling the drain valve, the pump, and the supply valve; Comprising; The control unit; Controls the drain valve and the pump so as to discharge the processing liquid from the inner tank, the outer tank, and the circulation pipe; After discharging the processing liquid, controls the supply valve so as to newly supply the processing liquid into the inner tank; After newly supplying the processing liquid, controls the drain valve and the pump so as to discharge the processing liquid stored in the inner tank to the lower limit level of the inner tank; After discharging the processing liquid to the lower limit level of the inner tank, controls the supply valve so as to newly supply the processing liquid into the inner tank; The lower limit level of the inner tank indicates a liquid level higher than the position of the circulating liquid inlet disposed inside the inner tank and also indicates a liquid level higher than the position of the fresh liquid supply port disposed inside the inner tank, a substrate processing apparatus.

Images