JP2015046443A - Apparatus for treating liquid, method for correcting concentration, and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for correcting a concentration of a treatment liquid, capable of feeding a treatment liquid adjusted to a desired concentration to a treating unit immediately after the start of correcting a concentration.SOLUTION: When a concentration of a treatment liquid present in a tank (102) and a circulation line (104) is out of a predetermined range, the concentration of the treatment liquid flowing through the circulation line is corrected by injecting a treatment liquid component into the circulation line at an injection position to mix with the treatment liquid flowing through the circulation line, using a concentration correction section (117), where the injection position is in the downstream side from the outlet of the tank and in the upstream side from a connection region to which a liquid treating unit is connected.

Description

  The present invention relates to a technique for correcting the concentration of a processing liquid in a tank for storing the processing liquid and a liquid processing apparatus in which the processing liquid is supplied to the liquid processing unit via a circulation line that leaves the tank and returns to the tank.

  The manufacturing process of a semiconductor device includes a liquid processing process in which a processing liquid such as a chemical liquid is supplied to a substrate such as a semiconductor wafer to perform a liquid processing such as an etching process and a cleaning process on the substrate. Such a liquid processing step is executed by a liquid processing apparatus (liquid processing system) including a plurality of liquid processing units.

  In such a liquid processing apparatus, processing liquid is supplied from a common processing liquid supply mechanism to a plurality of liquid processing units. The processing liquid supply mechanism has a tank and a circulation line that exits from the tank and returns to the tank. A plurality of branch lines are connected in parallel to the circulation line, and the processing liquid is supplied from each branch line to the corresponding liquid processing unit.

  The concentration of the treatment liquid existing in the circulation system composed of the tank and the circulation line changes due to evaporation, decomposition, etc. of the treatment liquid constituents that occur with time. In order to maintain the concentration of the processing liquid within a range appropriate for the liquid processing, the concentration is regularly adjusted. As described in Patent Document 1, concentration adjustment can be performed, for example, by introducing a new treatment solution having a high concentration into the tank.

  The high-concentration new processing liquid charged in the tank is mixed with the processing liquid already existing in the circulation system including the tank and the circulation line mainly by diffusing in the tank. However, the flow rate of the processing liquid in the tank is low, the flow rate distribution is non-uniform, and there are places where the processing liquid remains in the tank. Therefore, it takes a relatively long time until the new processing liquid and the existing processing liquid are completely mixed. If a part of the new high-concentration processing liquid flows out to the circulation line before sufficiently diffusing in the tank, a relatively high-concentration processing liquid may be supplied to the liquid processing unit. For this reason, there is a possibility that the processing result may vary even within the allowable range for a while after the start of the concentration adjustment of the processing liquid.

JP 2007-109738 A

  The present invention provides a treatment liquid concentration correction technique capable of supplying a treatment liquid adjusted to a desired concentration to a liquid treatment unit immediately after the start of concentration correction.

  In a preferred embodiment, the present invention is set in a tank for storing a processing liquid, a circulation line that exits from the tank and returns to the tank, a pump that circulates the processing liquid in the circulation line, and the circulation line. A branch line connected to the circulation line in the connected area, a liquid processing unit for processing the substrate using the processing liquid flowing into the branch line from the circulation line, and a downstream side of the outlet of the tank. In addition, at the injection position set upstream of the connection region, the processing liquid constituents are injected into the circulation line and mixed with the processing liquid flowing through the circulation line. Provided is a liquid processing apparatus including a concentration correction unit that corrects the concentration.

  In another preferred embodiment, the present invention includes a tank for storing a processing liquid, a circulation line that exits from the tank and returns to the tank, a pump that circulates the processing liquid in the circulation line, and the circulation line. In a liquid processing apparatus comprising: a branch line connected to the circulation line in a connection region set to a liquid processing unit; and a liquid processing unit for processing a substrate using a processing liquid flowing into the branch line from the circulation line. In the method for correcting the concentration of the liquid, when the concentration of the processing liquid existing in the tank and the circulation line is out of a predetermined range, it is downstream from the outlet of the tank and upstream from the connection region. At the injection position set on the side, by injecting treatment liquid components into the circulation line and mixing with the treatment liquid flowing through the circulation line, the circulation It provides a density correction method characterized by comprising a correction step of correcting the concentration of the treatment liquid flowing in.

  In still another preferred embodiment, the present invention provides the liquid processing apparatus further comprising a control unit including a computer, wherein the liquid processing apparatus executes the concentration correction method when executed by the control unit. A storage medium storing a program for controlling a liquid processing apparatus is provided.

  According to the embodiment of the invention described above, the concentration of the treatment liquid for correcting the concentration in the circulation line in which the treatment liquid flows at a relatively high flow rate as compared with the case where a new treatment liquid having a high concentration is introduced into the tank. Since the components are injected, the injected processing liquid components are quickly mixed with the existing processing liquid flowing toward the injection position. For this reason, by injecting the processing liquid component having an appropriate concentration at an appropriate flow rate, the concentration of the processing liquid at a position downstream of the injection position can be quickly adjusted to a desired concentration, which is immediately adjusted. It can utilize for the process in a liquid processing unit.

The piping diagram which shows roughly the whole structure of a liquid processing apparatus. The piping diagram shown in detail about the structure of the tank vicinity of a liquid processing apparatus. Sectional drawing which shows the structure of the circulation line of the injection | pouring position vicinity. The time chart explaining density correction operation. The schematic piping figure explaining other embodiment of a liquid processing apparatus.

  Embodiments of the invention will be described below with reference to the accompanying drawings.

  As shown in FIG. 1, the liquid processing apparatus includes a plurality of processing units (liquid processing units) 16 that perform liquid processing on a substrate, and a processing fluid supply source 70 that supplies the processing liquid to the processing units 16. Yes.

  The processing fluid supply source 70 includes a tank 102 that stores the processing liquid, and a circulation line 104 that exits from the tank 102 and returns to the tank 102. The circulation line 104 is provided with a pump 106. The pump 106 creates a circulating flow that exits the tank 102, passes through the circulation line 104, and returns to the tank 102. A filter 108 for removing contaminants such as particles contained in the processing liquid is provided in the circulation line 104 on the downstream side of the pump 106. If necessary, auxiliary equipment (such as a heater) may be further provided in the circulation line 104.

  One or more branch lines 112 are connected to the connection area 110 set in the circulation line 104. Each branch line 112 supplies the processing liquid flowing through the circulation line 104 to the corresponding processing unit 16. Each branch line 112 can be provided with a flow rate adjusting mechanism such as a flow rate control valve, a filter, or the like, if necessary.

  The liquid processing apparatus includes a tank liquid replenishing unit 116 that replenishes the tank 102 with a processing liquid or a processing liquid constituent component. The tank 102 is provided with a drain unit 118 for discarding the processing liquid in the tank 102.

  As shown in FIG. 2, the liquid processing apparatus includes a control device 4. The control device 4 is a computer, for example, and includes a control unit 18 and a storage unit 19. The storage unit 19 stores a program for controlling various processes executed in the liquid processing apparatus. The control unit 18 controls the operation of the liquid processing apparatus by reading and executing the program stored in the storage unit 19.

  Such a program may be recorded on a computer-readable storage medium, and may be installed in the storage unit 19 of the control device 4 from the storage medium. Examples of the computer-readable storage medium include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magnetic optical disk (MO), and a memory card.

  Next, the configuration in the vicinity of the tank 102 of the liquid processing apparatus shown in FIG. 1 will be described in more detail with reference to FIG. Although not shown in FIG. 2, a connection region 110 is set in the circulation line 104 as in FIG. 1, and one or a plurality of branch lines 112 are connected thereto, and the liquid processing unit 16 is connected to each branch line 112. Is connected. In the following description, the treatment liquid has a predetermined concentration obtained by diluting a high concentration chemical solution (CHM) such as 50% hydrofluoric acid (HF) with pure water (DIW) as a diluent, for example, a concentration of about 0.5%. It shall be dilute hydrofluoric acid (DHF).

  The tank liquid replenishment unit 116 includes a high concentration chemical solution supply unit 116A and a diluent supply unit 116B. The high-concentration chemical solution supply unit 116A includes a high-concentration chemical solution supply source 161a that stores the high-concentration chemical solution, and a high-concentration chemical solution supply line 162a that connects the high-concentration chemical solution supply source 161a and the tank 102. A pump 163a, an on-off valve 164a, a flow meter 165a, and a flow rate control valve 166a are provided in this order from the upstream side in the high concentration chemical solution supply line 162a. The diluent supply unit 16B has a diluent supply source 161b, and a diluent supply line 162b that connects the diluent supply source 161b and the tank 2. A pump 163b, an on-off valve 164b, a flow meter 165b, and a flow control valve 166b are provided in this order from the upstream side in the diluent supply line 162b. The tank liquid replenishment unit 116 can supply the high-concentration chemical liquid and the diluting liquid to the tank 102 at flow rates controlled independently of each other. The tank liquid replenishing unit 116 is used when periodically replacing all or most of the processing liquid, or when replenishing the processing liquid in the tank 2 that has been reduced by the liquid processing.

  The drain part 118 includes a drain line 181 connected to the tank and an open / close valve 182 interposed in the drain line 181.

  The liquid processing apparatus further includes a line liquid concentration correction unit 117 not shown in FIG.

  The line liquid concentration correction unit 117 includes a high concentration chemical solution supply unit 117A and a diluent supply unit 117B. The high-concentration chemical supply unit 117A of the line liquid concentration correction unit 117 includes a high-concentration chemical supply source 161a and a pump 163a that are shared with the high-concentration chemical supply unit 116A of the tank liquid replenishment unit 116 described above. The dilution liquid supply unit 117B of the line liquid concentration correction unit 117 also includes a dilution liquid supply source 161b and a pump 163b that are shared with the dilution liquid supply unit 116B of the tank liquid replenishment unit 116.

  The high concentration chemical liquid supply unit 117A of the line liquid concentration correction unit 117 includes a high concentration chemical liquid supply line 171a. The high concentration chemical liquid supply line 171a branches from the high concentration chemical liquid supply line 162a of the high concentration chemical liquid supply unit 116A between the pump 163a and the on-off valve 164a. The high concentration chemical solution supply line 171a is connected to the circulation line 104 at a position Pi (injection position) downstream of the outlet of the tank 102 and upstream of the pump 106. The high-concentration chemical supply line 171a is provided with an open / close valve 178a, a flow meter 172a, a flow control valve 173a, and an open / close valve 174a in this order from the upstream side. At a position between the flow control valve 173a and the on-off valve 174a, a drain line 175a branches from the high concentration chemical liquid supply line 171a. The drain line 175a is provided with an on-off valve 176a.

  The diluent supply unit 117B of the line solution concentration correction unit 117 has a diluent supply line 171b. The diluent supply line 171b branches from the diluent supply line 162b of the diluent supply part 16B between the pump 163b and the on-off valve 164b. The dilution liquid supply line 171b is connected to the high concentration chemical liquid supply line 171a at a position downstream of the on-off valve 174a. The diluent supply line 171b is provided with an open / close valve 178b, a flow meter 172b, a flow control valve 173b, and an open / close valve 174b in this order from the upstream side. A drain line 175b branches from the diluent supply line 171b at a position between the flow control valve 173b and the on-off valve 174b. The drain line 175b is provided with an on-off valve 176b.

  A return line 120 (not shown in FIG. 1) for returning a part of the processing liquid flowing through the circulation line 104 to the tank 102 is connected to the filter 108. The return line 120 can be used for bleeding the filter 108. The return line 120 is provided with a densitometer 122 that measures the concentration of the processing liquid. The position where the densitometer 22 is provided is not limited to the return line 120, but may be any position where the concentration of the processing liquid existing in the circulation system including the tank 102 and the circulation line 104 can be measured. be able to. In addition, a liquid level meter 124 that detects the liquid level of the processing liquid in the tank 102 is provided in the tank 102.

  FIG. 3 shows a structure of a connection portion (injection position Pi) between the high-concentration chemical solution supply line 171a and the circulation line 104 after joining with the diluent supply line 171b. A high-concentration chemical solution supply line 171a made of piping is inserted into a hole made in the circulation line 104 made of piping. The open end of the high-concentration chemical solution supply line 171a opens at the center of the cross section of the circulation line 104.

  Next, the operation of the liquid processing apparatus will be described. During operation of the liquid processing apparatus, the processing liquid is circulated through the circulation line 104 by the pump 106. If necessary, the processing liquid is sent from the circulation line 104 to the liquid processing unit 114 via the branch line 112 via an on-off valve and a flow rate control valve (not shown) provided on the branch line 112. The liquid processing unit 114 performs a predetermined liquid processing on the substrate using the sent processing liquid.

  The amount of the processing liquid in the tank 12 decreases with time due to the liquid processing performed in the processing unit 16. Therefore, when the processing liquid is reduced by a predetermined amount, the processing liquid is replenished into the tank 102 from the tank liquid replenishing unit 116. The liquid processing continues while the processing liquid is replenished. Further, the concentration of the processing liquid contained in the circulation system including the tank 102 and the circulation line 104 changes with time due to evaporation, decomposition, and the like of the solvent (diluent). For example, when the treatment liquid is DHF (dilute hydrofluoric acid), the HF concentration in DHF gradually decreases with time. Hereinafter, an operation for correcting the HF concentration in the DHF according to the present embodiment will be described with reference to FIG. The DHF concentration correction operation described below is performed under the control of the control device 4.

  The vertical axis of the upper graph in FIG. 4 indicates that the circulation line 104 is connected to the connection region 110 of the liquid processing unit 16 (see FIG. 5) downstream of the position where the high-concentration chemical supply line 171a is joined after joining the diluent supply line 171b. 1), the concentration of DHF flowing toward the head. Here, the detected value of the densitometer 122 of the return line 120 that can be regarded as being substantially equal to the concentration of DHF flowing toward the connection region 110 can be used. Also, the vertical axis of the lower graph in FIG. 4 represents the detected value (HF flow rate) of the flow meter 172a of the high concentration chemical solution supply line 171a and the detected value (DIW flow rate) of the flow meter 172b of the diluted solution supply line 171b, respectively. Show. The horizontal axis of the upper and lower graphs in FIG. 4 indicates the elapsed time.

  When the HF concentration in the DHF flowing through the circulation line 104 decreases with time and falls below the “correction start lower limit value” (see times t1 to t2), that is, when the HF concentration is out of a predetermined range, the circulation line 104 The concentration correction operation is started in a state where the circulation of the DHF and the substrate processing in the liquid processing unit 16 are continued. The “correction start lower limit (upper limit) value” is a value that triggers the start of the concentration correction operation, and is larger than an allowable upper limit (lower limit) value that is a criterion for determining whether or not the liquid processing unit 16 can be used. (Small) value.

  First, during the time t2, the on-off valve 182 of the drain part 118 is opened, and DHF in the tank 2 is discharged from the drain line 181. The discharge of DHF is performed while monitoring the liquid level in the tank 102 by the liquid level gauge 124, and the DHF remaining in the tank 102 is reduced to a predetermined amount (for example, an amount corresponding to 2/3 of the tank capacity). Can continue. While the liquid treatment is continued, the liquid level in the tank 102 fluctuates. However, by monitoring the liquid level in the tank 102, the liquid level in the tank 102 can be grasped. The amount of liquid can also be grasped.

  Since DHF circulates in the circulation line 104 as in normal operation, the total amount of DHF present in the circulation system including the tank 102 and the circulation line 104 at the time when drainage from the tank 102 is completed. Is grasped as the sum of the amount of the processing liquid in the tank 102 obtained from the above liquid level monitoring result and the total internal volume of the circulation line 104 that can be calculated from the pipe diameter and pipe length of the circulation line 104. be able to. Further, the concentration of DHF present in the circulatory system can be considered to be uniform and the same as the detection value of the densitometer 124. Therefore, the concentration of the DHF for concentration correction supplied to the circulation line 104 from the line liquid concentration correction unit 117 and the concentration necessary for setting the concentration of DHF existing in the circulation system to a target value (for example, the median value of the allowable range) and The total amount can be obtained by calculation. The concentration correction DHF supplied from the line liquid concentration correction unit 117 to the circulation line 104 is immediately mixed with the existing DHF flowing through the circulation line 104 and flows toward the connection region 110 of the liquid processing unit 16. The concentration and flow rate of the correction DHF are adjusted so that the DHF concentration after mixing is immediately within the predetermined range (between the correction start upper limit value and the lower limit value), preferably the target value described above. It is obtained by calculation in consideration of the concentration and flow rate of the existing DHF flowing toward the injection position Pi. In addition, since the flow rate of the liquid discharged from the pump 106 to the downstream side during the rated operation is constant and known, the flow rate of the existing DHF flowing into the pump 106 (this is the flow rate of the existing DHF flowing toward the injection position Pi). Is equal to the value obtained by subtracting the flow rate of the DHF for concentration correction supplied from the line liquid concentration correction unit 117 to the circulation line 104 from the discharge flow rate of the pump 106, and the above calculation is performed. Good. Note that a flow meter for measuring the flow rate of the existing processing liquid flowing through the circulation line 104 toward the injection position Pi may be provided, and the above calculation may be performed based on the detected value of the flow meter. The above calculation is executed by the control device 4.

  A high concentration (for example, 50%) of HF is supplied via the high concentration chemical supply line 171a so that the concentration correction DHF is supplied from the line concentration correction unit 117 to the circulation line 104 at the calculated concentration and flow rate. DIW is supplied from the diluent supply line 171b to the circulation line 104 at a predetermined flow rate and flow rate ratio.

  First, the on-off valves 164a, 164b, 174a, 174b are closed, and the on-off valves 176a, 176b, 178a, 178b are opened. Further, the opening degree of the flow rate adjusting valves 173a and 173b is feedback controlled using the detected values of the flow meters 172a and 172b so that the pumps 163a and 163b are operated and the HF flow rate and DIW flow rate obtained by calculation are realized. Is done. Since the flow rate does not stabilize for a while from the start of the pumps 163a and 163b, HF and DIW are discarded from the drain lines 175a and 175b and wait until the flow rate is stabilized. This operation is performed during time t2.

  When the flow rate of HF flowing through the high-concentration chemical supply line 171a and the flow rate of DIW flowing through the diluent supply line 171b are stabilized, the open / close valves 174a and 174b are opened and the open / close valves 176a and 176b are opened. Then, the HF that has flowed through the high-concentration chemical supply line 171a and the DIW that has flowed through the diluent supply line 171b are mixed at a predetermined ratio, and the existing flow that flows through the circulation line 104 as shown in FIG. Added (injected) into the DHF. The DHF for concentration correction is immediately mixed with the existing DHF flowing through the circulation line 104, so that the DHF having substantially reached the target concentration flows toward the connection region 110 of the liquid processing unit 16.

  The supply of the density correction DHF is terminated when the previously calculated total supply quantity of the density correction DHF (total supply quantity of HF + total supply quantity of DIW) has been supplied to the circulation line 4 (end of time t3). ). The fact that the total supply amount of the concentration correction DHF has reached the calculated value can be detected based on, for example, the time integration value of the detection values of the flow meters 172a and 172b. The supply of the density correction DHF may be terminated when the detection value of the densitometer 122 exceeds a predetermined value.

  By the way, since the concentration of DHF circulating in the circulation line 104 gradually increases during the time t3, if the concentration correction DHF having the same concentration is continuously supplied from the line liquid concentration correction unit 117, the DHF ( The concentration of this is supplied to the connection region 10 of the liquid processing unit 16 as it is) gradually increases. If this is unacceptable, the concentration of DHF for concentration correction may be gradually decreased by changing the mixing ratio of HF and DIW based on the detected value of the concentration meter 122. . On the other hand, if such a concentration increase is acceptable, the concentration of the concentration correction DHF supplied from the line liquid concentration correction unit 117 to the circulation line 104 during time t3 may be constant.

  According to the above embodiment, the concentration correction DHF is supplied into the circulation line 104 in which the existing DHF flows at a relatively high flow rate as compared with a case where a new treatment liquid with a high concentration is introduced into the tank. Therefore, the existing DHF and the concentration correction DHF are quickly mixed, and the existing DHF and the concentration correction DHF are mixed in a very short time (the mixture reaches the connection region of the liquid processing unit 16). To a uniform intended concentration of DHF. For this reason, the liquid processing result in the liquid processing unit 16 does not vary due to fluctuations in the DHF concentration.

  In addition, in the present embodiment, since the injection position Pi of the concentration correction DHF is on the upstream side of the pump 106, mixing of the concentration correction DHF and the existing DHF is promoted when passing through the pump 106. Therefore, the above effect can be achieved more reliably. If the concentration correction DHF and the existing DHF are sufficiently mixed before the mixed solution reaches the connection region 110 of the liquid processing unit 16, the injection position Pi of the concentration correction DHF is set to It may be set downstream of the pump 106.

  In the above embodiment, some of the constituent members of the line liquid concentration correction unit 117 (part of the line, pump, supply source, etc.) are shared with the tank liquid replenishing unit 116. A dedicated line liquid concentration correction unit 117 may be provided.

  In the above embodiment, the line liquid concentration correction unit 117 injects a mixture of HF and DIW, which are constituent components of the processing liquid DHF, into the circulation line 104. However, HF and DIW are separately supplied to the circulation line. 104 may be injected.

  The on-off valves 174a and 176a (or on-off valves 174b and 176b) may be integrated into one three-way valve.

  In the above embodiment, the treatment liquid is DHF, and DHF having a higher concentration (a mixture of about 50% HF and DIW) is used as the concentration correction additive liquid, but is not limited thereto. In some cases, a stock solution of HF (about 50% HF) that has not been diluted with DIW may be used as an additive solution for concentration correction.

  In the above-described embodiment, the treatment liquid is a mixture of the chemical liquid component (HF) and the diluted component (DIW), and the chemical liquid component in the mixture is lost due to the change over time, and the treatment liquid concentration is reduced. However, it is not limited to this. The concentration correction can also be applied when the concentration of the processing solution increases due to the loss of diluted components due to the change over time. In this case, it is possible to use only a processing solution having a concentration lower than the normal processing solution concentration or a diluting component as an additive solution for concentration correction. In the above embodiment, the treatment liquid is substantially a two-component system (hydrofluoric acid and water), but the treatment liquid is a multi-component system (for example, a mixture of a plurality of types of acids, alkalis, and water). In this case, the concentration correction may be performed using an additive solution for concentration correction including one or more kinds of processing liquid constituent components.

  In the above embodiment, the liquid processing system has one circulation line 104 starting from the tank 102 and returning to the tank 102, and the liquid processing unit 16 is connected via the branch line 112 branched from the circulation line 104. However, the circulation line 104 is not limited to a single line from the start point to the end point. The circulation line 4 of the liquid processing apparatus may be branched into a plurality of lines along the way as shown in FIG.

  In FIG. 5, the same or similar components as those shown in FIG. In the liquid processing apparatus shown in FIG. 5, the circulation line 104 branches into a number of sub circulation lines 104 a, 104 b, 104 c corresponding to the number of liquid processing units 14. Each sub-circulation line is provided with an orifice 130 and a control valve 132. The control valve 132 controls the pressure of the processing liquid in the auxiliary circulation line between the orifice 130 and the control valve 132 by adjusting the flow rate of the processing liquid flowing downstream therethrough, thereby The flow rate supplied to the liquid processing unit 14 through the branch line 112 is controlled. The auxiliary circulation lines 104 a, 104 b, and 104 c merge into one line again and are connected to the tank 102. The auxiliary circulation lines 104a, 104b, and 104c may be individually connected to the tank 102. Also in this case, the same effect as the embodiment shown in FIGS. 1 and 2 can be obtained by injecting the concentration correction additive liquid into the circulation line 104 by the line liquid concentration correction unit 117.

DESCRIPTION OF SYMBOLS 102 Tank 104 Circulation line 106 Pump 112 Branch line 16 Liquid processing unit 117 Concentration correction | amendment part 4 Control part (control apparatus)
Pi injection position

Claims (8)

A tank for storing the processing liquid;
A circulation line exiting the tank and returning to the tank;
A pump for circulating the treatment liquid in the circulation line;
A branch line connected to the circulation line in a connection region set to the circulation line;
A liquid processing unit for processing a substrate using the processing liquid flowing into the branch line from the circulation line;
Injecting treatment liquid components into the circulation line and mixing with the treatment liquid flowing through the circulation line at an injection position set downstream from the tank outlet and upstream from the connection region. A concentration correction unit for correcting the concentration of the treatment liquid flowing through the circulation line,
A liquid processing apparatus comprising:   The liquid processing apparatus according to claim 1, wherein the injection position is located downstream of the tank of the circulation line and upstream of the pump. A tank for storing the processing liquid; a circulation line that exits from the tank and returns to the tank; a pump that circulates the processing liquid in the circulation line; and a connection region that is set in the circulation line. In a liquid processing apparatus comprising a branch line and a liquid processing unit for processing a substrate using a processing liquid flowing into the branch line from the circulation line, a method for correcting the concentration of the processing liquid,
When the concentration of the processing liquid existing in the tank and the circulation line is out of a predetermined range, at the injection position set downstream from the outlet of the tank and upstream from the connection region, A concentration correction method comprising: a correction step of correcting the concentration of the processing liquid flowing through the circulation line by injecting the processing liquid constituents into the circulation line and mixing with the processing liquid flowing through the circulation line. .   The concentration correction method according to claim 3, wherein the injection position is located downstream of the tank and upstream of the pump in the circulation line.   The configuration of the processing liquid injected into the injection position based on the concentration of the processing liquid already existing in the tank and the circulation line and the flow rate of the processing liquid flowing in the circulation line toward the injection position A component of the processing liquid to be injected into the injection position so that the concentration of the liquid mixture of the component and the processing liquid flowing through the circulation line toward the injection position becomes a target value within the predetermined range immediately after mixing. 5. The concentration correction method according to claim 3, further comprising a calculation step of obtaining a concentration and an injection flow rate, wherein in the correction step, the processing liquid component is injected at the concentration and injection flow rate obtained by the calculation step.   In the calculation step, in the tank and the circulation line at the end of the correction step, based on the concentration and total amount of the treatment liquid existing in the tank and the circulation line before the start of the correction step. The total injection amount of the treatment liquid component necessary for setting the treatment liquid concentration of the existing treatment liquid to the target value within the predetermined range was calculated, and the total injection amount of the treatment liquid component was calculated in the correction step. The density correction method according to claim 5, which is terminated when it is detected that the value has been reached.   Further comprising a discarding step of discarding a part of the processing liquid in the tank and the circulation line so that a total amount of the processing liquid in the tank and the circulation line becomes a predetermined value before the start of the correction step; The concentration correction method according to claim 6, wherein the calculation of the total injection amount of the processing liquid component in the process is performed based on the total amount of the processing liquid existing in the tank and the circulation line after the disposal process is completed.   A tank for storing the processing liquid; a circulation line that exits from the tank and returns to the tank; a pump that circulates the processing liquid in the circulation line; and a connection region that is set in the circulation line. A branch line, a liquid processing unit for processing a substrate using the processing liquid flowing into the branch line from the circulation line, and a downstream side of the tank outlet and an upstream side of the connection region. A concentration correction unit that corrects the concentration of the processing liquid flowing through the circulation line by injecting a processing liquid component into the processing liquid flowing through the circulation line at the injection position, and a control unit that includes a computer. A storage medium storing a program for controlling the liquid processing apparatus, which is executed by a control unit comprising the computer. A storage medium wherein the liquid processing apparatus to perform the density correction process according to any one of claims 3 7.

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