JP2009049330A - Substrate processing equipment, method for processing substrate and device for controlling concentration of processing liquid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate processing equipment that accurately controls the concentration of a processing liquid circulating through a circulating route when processing a substrate by allowing the processing liquid to circulate and supply to the substrate during conveyance thereof. <P>SOLUTION: The substrate processing equipment having a concentration monitor 14 for measuring the concentration of the processing liquid circulating through the circulation route calculates the volume of the processing liquid which is bonded to the substrate W being processed while being conveyed by a conveyance roller 24 in a processing tank 18 to the outside thereof, based on the processing liquid supplied to one sheet of the substrate and the number of the substrate being processed. The equipment calculates the volume of the chemical to be replenished on the way of the circulating route, and fills the way of the circulating route with the calculated volume of the chemical, based on the calculated volume of the processing liquid being used and concentration thereof measured by the concentration monitor 14. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention performs processing such as etching on various substrates such as semiconductor wafers, glass substrates for liquid crystal display devices, glass substrates for plasma display (PDP), magnetic disk substrates, optical disk substrates, and photomask glass substrates. The present invention relates to a substrate processing apparatus and a substrate processing method, and a concentration management apparatus that manages the concentration of a processing solution such as an etching solution that is used while being circulated when processing such as etching is performed on a substrate.

  For example, in a semiconductor device manufacturing process, substrates are sequentially carried into a processing tank one by one, and are arranged in a processing tank while supporting the substrate by a plurality of transport rollers in the processing tank and transporting it horizontally. In a substrate processing apparatus that supplies a processing solution such as an etching solution, a stripping solution, a developing solution, and a cleaning solution from the discharge nozzle to the surface of the substrate and performs processing such as etching, resist film peeling, development, and cleaning on the substrate, the discharging nozzle The processing liquid supplied from the substrate to the substrate is collected in the storage tank and circulated. That is, the recovery pipe is connected to the bottom of the processing tank, the recovery pipe is connected to the storage tank, and the bottom of the storage tank and the discharge nozzle in the processing tank are connected to each other through the supply pipe. A processing liquid is supplied from the storage tank to the discharge nozzle by a supply pump inserted in the middle of the piping, and the processing liquid is discharged from the discharge nozzle to the surface of the substrate. Then, the processing liquid supplied from the discharge nozzle to the surface of the substrate and flowing down from the substrate surface to the bottom of the processing liquid or the processing liquid discharged from the discharge nozzle and flowing down to the bottom of the processing liquid as it is is collected from the bottom of the processing liquid. It collects in a storage tank through piping, and it is made to use it, circulating the processing liquid. In addition, the storage tank is configured to be appropriately replenished with processing liquid (see, for example, Patent Document 1).

By the way, when etching a metal film formed on a substrate, such as an aluminum film, for example, a mixed solution of nitric acid, acetic acid, phosphoric acid and pure water is used as an etching solution, and the etching solution is circulated. Supply to the substrate. Thus, since the etching solution is used while being circulated, the composition of the etching solution gradually changes as the number of substrates processed increases. More specifically, as the number of substrates processed increases, the concentrations of nitric acid and acetic acid in the etching solution gradually decrease, while the concentration of phosphoric acid increases and pure water slightly decreases. As a result, for example, when the concentration of nitric acid decreases, the viscosity of the etching solution increases and the etching characteristics become unstable. Therefore, the concentration of nitric acid in the etching solution is measured at regular intervals, and the chemical solution such as nitric acid is replenished as needed to the etching solution according to the measured concentration so that the concentration of each component in the etching solution becomes the target concentration. Need to manage. In this case, the conventional concentration management system uses the measured concentration value and the value (constant value) of the total capacity of the storage tank, and the amount of chemical solution required to return the concentration of the processing liquid in the storage tank to the target concentration And the calculated amount of the chemical solution was replenished.
JP-A-10-74726 (page 3, FIG. 1)

  However, during the processing of the substrate, a part of the processing liquid supplied from the discharge nozzle to the substrate carried into the processing tank remains on the surface of the substrate and is transported from the processing tank. It is taken out of the processing tank together. As a result, the amount of the processing liquid in the circulation path decreases little by little, and the liquid level of the processing liquid in the storage tank gradually decreases. For this reason, if the replenishment amount of the chemical liquid is calculated using the value of the total capacity of the storage tank as in the conventional concentration management system, the concentration of the processing liquid in the storage tank does not return to the target concentration due to the replenishment of the chemical liquid. There is a problem such as.

  The present invention has been made in view of the circumstances as described above. The substrates are sequentially carried into the processing tank one by one, and the processing liquid is supplied to the substrate while transporting the substrates in the horizontal direction in the processing tank. A substrate processing apparatus and a substrate processing method capable of accurately managing the concentration of a processing solution circulating through a circulation path when a substrate is processed while being supplied while being circulated, and a substrate after processing is carried out from a processing tank. An object of the present invention is to provide a treatment liquid concentration management apparatus capable of accurately managing the concentration of the treatment liquid circulating through the circulation path.

  According to the first aspect of the present invention, the substrates are sequentially carried into the processing tank one by one, and the substrate is processed by supplying the processing liquid to the substrate while circulating the substrate in the horizontal direction in the processing tank. In the substrate processing apparatus for carrying out the processed substrate from the processing tank, the concentration measuring means for measuring the concentration of the processing liquid circulating through the circulation path, and the processing attached to the processed substrate and taken out of the processing tank A carry-out amount calculating means for calculating the amount of the liquid from a carry-out amount of the processing liquid per substrate and the number of processed substrates; a concentration of the treatment liquid measured by the concentration measuring means; and the carry-out amount calculating means A replenishment amount calculating means for calculating the amount of the chemical solution to be replenished in the middle of the circulation path, a replenishment means for replenishing the chemical liquid in the middle of the circulation path, and the replenishment Liquid volume And control means for controlling said replenishing means to replenish the liquid medicine calculated replenishing amount in the middle of the circulation path by detecting means characterized by comprising a.

  According to a second aspect of the present invention, in the substrate processing apparatus according to the first aspect, in the calculation of the amount of processing liquid to be taken out by the carry-out amount calculating means, the value of the amount of processing liquid to be taken out per substrate is a processing liquid. The amount of the processing liquid that is naturally lost in the circulation path due to evaporation of the water is added and reset as appropriate.

  According to a third aspect of the present invention, in the substrate processing apparatus according to the first or second aspect, the processing liquid is an etching liquid made of a mixed solution of nitric acid, acetic acid, phosphoric acid and pure water, and the replenishing means It is characterized by supplementing with high concentrations of nitric acid and acetic acid, respectively.

  In the invention according to claim 4, the substrates are sequentially carried into the processing tank one by one, and the substrate is processed by supplying the processing liquid to the substrate while circulating the substrate in the processing tank in the horizontal direction. In the substrate processing method for carrying out the processed substrate from the processing tank, a concentration measuring step for measuring the concentration of the processing liquid circulating through the circulation path, and a process of attaching to the processed substrate and taking it out of the processing tank A carry-out amount calculating step for calculating the amount of the liquid from a carry-out amount of the processing liquid per substrate and the number of processed substrates; a concentration of the treatment liquid measured in the concentration measuring step; and the carry-out amount calculating step The replenishment amount calculating step for calculating the amount of the chemical solution to be replenished in the middle of the circulation path based on the carry-out amount of the processing liquid calculated in step (b), and the replenishment amount of the chemical solution calculated in the replenisher amount calculating step Refill in the middle of the circulation path A replenishing step that, characterized in that it comprises a.

  According to a fifth aspect of the present invention, in the substrate processing method according to the fourth aspect, in the calculation of the processing liquid take-out amount in the take-out amount calculating step, the value of the processing liquid take-out amount per substrate is a processing amount. The amount of the processing liquid that is naturally lost in the circulation path due to the evaporation of the liquid is added and reset as appropriate.

  The invention according to claim 6 is the substrate processing method according to claim 4 or claim 5, wherein the processing solution is an etching solution made of a mixed solution of nitric acid, acetic acid, phosphoric acid and pure water, and in the replenishing step. It is characterized by supplementing with high concentrations of nitric acid and acetic acid, respectively.

  The invention according to claim 7 is the concentration of the processing liquid for managing the concentration of the processing liquid supplied while being circulated to the substrate which is sequentially carried into the processing tank one by one and transported in the horizontal direction in the processing tank. In the management apparatus, the concentration measuring means for measuring the concentration of the processing liquid circulating through the circulation path, and the amount of the processing liquid that adheres to the processed substrate and is taken out of the processing tank, Based on the carry-out amount calculation means calculated from the carry-out amount and the number of processed substrates, the concentration of the treatment liquid measured by the concentration measurement means, and the treatment liquid carry-out amount calculated by the carry-out amount calculation means, A replenishment amount calculating means for calculating the amount of the chemical solution to be replenished in the middle of the circulation path, a replenishment means for replenishing the chemical liquid in the middle of the circulation path, and a replenishment amount of the chemical liquid calculated by the replenishment liquid amount calculation means Characterized by comprising a control means for controlling said replenishing means so as to replenish in the middle of the circulation path.

  According to an eighth aspect of the present invention, in the concentration management apparatus according to the seventh aspect, in the calculation of the amount of processing liquid to be taken out by the carry-out amount calculating means, the value of the amount of processing liquid to be taken per substrate is a processing liquid. The amount of the processing liquid that is naturally lost in the circulation path due to evaporation of the water is added and reset as appropriate.

  The invention according to claim 9 is the concentration management apparatus according to claim 7 or claim 8, wherein the treatment liquid is an etching liquid made of a mixed solution of nitric acid, acetic acid, phosphoric acid and pure water, and the replenishing means It is characterized by supplementing with high concentrations of nitric acid and acetic acid, respectively.

In the substrate processing apparatus according to the first aspect of the present invention, the recirculation path is based on the concentration of the processing liquid measured by the concentration measuring means and the carry-out amount of the processing liquid calculated by the carry-out amount calculating means by the replenishment amount calculating means. The replenishment amount of the chemical solution is calculated, and the replenishment unit is controlled by the control unit, so that an appropriate amount of the chemical solution is replenished in the circulation path, so that the concentration of the processing liquid circulating through the circulation path is more accurately set to the target concentration. Retained.
Therefore, when the substrate processing apparatus according to the first aspect of the present invention is used, the concentration of the processing liquid circulating through the circulation path can be accurately managed, and the substrate can be processed stably.

  In the substrate processing apparatus according to the second aspect of the present invention, the amount of the processing liquid remaining on the surface of the substrate during processing of the substrate and taken out of the processing tank together with the substrate is increased in the circulation path by evaporation of the processing liquid. By adding the amount of processing liquid that is lost naturally, the amount of processing liquid taken out per substrate is reset as appropriate, so that the concentration of the processing liquid circulating through the circulation path is more accurately maintained at the target concentration. can do.

  In the substrate processing apparatus according to the third aspect of the present invention, the concentration of each component of the etchant circulating through the circulation path is managed by replenishing the circulation path with high concentrations of nitric acid and acetic acid, respectively.

According to the substrate processing method of the invention according to claim 4, the replenishment amount of the chemical solution to the circulation path is calculated based on the measured value of the concentration of the treatment liquid and the calculated value of the carry-out amount of the treatment liquid, and is appropriate in the circulation path. Since the amount of the chemical solution is replenished, the concentration of the processing solution circulating through the circulation path is more accurately maintained at the target concentration.
Therefore, when the substrate processing method of the invention according to claim 4 is used, it is possible to accurately manage the concentration of the processing liquid circulating through the circulation path and to stably process the substrate.

  In the substrate processing method of the invention according to claim 5, in the circulation path by evaporation of the processing liquid, the amount of the processing liquid remaining on the surface of the substrate during the processing of the substrate and taken out of the processing tank together with the substrate. By adding the amount of processing liquid that is lost naturally, the amount of processing liquid taken out per substrate is reset as appropriate, so that the concentration of the processing liquid circulating through the circulation path is more accurately maintained at the target concentration. can do.

  In the substrate processing method according to the sixth aspect of the invention, the concentration of each component of the etching solution circulating through the circulation path is managed by replenishing the circulation path with high concentrations of nitric acid and acetic acid, respectively.

In the concentration management apparatus according to the first aspect of the present invention, the recirculation path is based on the concentration of the processing liquid measured by the concentration measuring means and the amount of the processing liquid taken out by the amount-of-taking-out calculating means. The replenishment amount of the chemical solution is calculated, and the replenishment unit is controlled by the control unit, so that an appropriate amount of the chemical solution is replenished in the circulation path, so that the concentration of the processing liquid circulating through the circulation path is more accurately set to the target concentration. Retained.
Therefore, when the concentration management apparatus of the invention according to claim 1 is used, the concentration of the processing liquid circulating through the circulation path can be accurately managed.

  In the concentration management apparatus according to the second aspect of the present invention, the amount of the processing liquid remaining on the surface of the substrate during the processing of the substrate and taken out of the processing tank together with the substrate is increased in the circulation path by evaporation of the processing liquid. By adding the amount of processing liquid that is lost naturally, the amount of processing liquid taken out per substrate is reset as appropriate, so that the concentration of the processing liquid circulating through the circulation path is more accurately maintained at the target concentration. can do.

  In the concentration management apparatus according to the third aspect of the present invention, the concentration of each component of the etchant circulating through the circulation path is managed by replenishing the circulation path with high-concentration nitric acid and acetic acid, respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the best embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows an example of an embodiment of the present invention, and is a diagram showing a schematic configuration of a substrate processing apparatus provided with a processing liquid concentration management apparatus. In this embodiment, a substrate processing apparatus for etching a metal film formed on a substrate, for example, an aluminum film, using an etching solution made of a mixed solution of nitric acid, acetic acid, phosphoric acid and pure water will be described as an example. To do.

  The substrate processing apparatus includes an apparatus main body 12 having an etching processing unit 10 and a concentration monitor 14 that measures the concentration of components in the etching solution, for example, nitric acid, and manages the concentration of the etching solution that circulates through the circulation path. 16. The etching processing unit 10 includes a processing tank 18 having a substrate carry-in port 20 and a substrate carry-out port 22, and a plurality of transfer rollers 24 that support the substrate W loaded into the process tank 18 in a horizontal posture and transfer the substrate W in the horizontal direction. , And a plurality of discharge nozzles 26 for supplying an etching solution to the surface of the substrate W transported by the transport roller 24.

  An etching solution recovery pipe 28 is connected to the bottom of the processing tank 18, and the recovery pipe 28 is connected to a storage tank 30. An etching solution supply pipe 32 communicates with and is connected to the bottom of the storage tank 30. A supply pump 34 is interposed in the supply pipe 32, and the supply pipe 32 is connected to the discharge nozzle 26 in a flow path. Then, the substrate processing unit 10 supplies the etching liquid from the discharge nozzle 26 to the surface of the substrate W while sequentially transporting the substrates W one by one, and etches the aluminum film formed on the substrate W into a predetermined pattern. . The etching solution that is supplied from the discharge nozzle 26 to the surface of the substrate W and flows down from the substrate W to the bottom of the processing bath 18 and the etching solution that is discharged from the discharge nozzle 26 and flows down to the bottom of the processing bath 18 as it is. 18 flows into the storage tank 30 through the recovery pipe 28 from the bottom of 18 and is recovered. The etching solution 36 stored in the storage tank 30 is supplied to the discharge nozzle 26 through the supply pipe 32 by the supply pump 34 and is discharged from the discharge nozzle 26. In this way, the etching solution is supplied to the substrate W in the processing tank 18 while circulating through the bottom of the processing tank 18, the recovery pipe 28, the storage tank 30, the supply pipe 32 and the discharge nozzle 26. .

  A circulation pipe 38 is connected to the bottom of the storage tank 30 in communication. A circulation pump 40 is inserted into the circulation pipe 38, and the circulation pipe 38 is connected to the upper portion of the storage tank 30. A replenishment pipe 42 is connected in the middle of the circulation pipe 38, and the replenishment pipe 42 is connected to the chemical liquid replenishment unit 44. Then, the chemical liquid supplied from the chemical liquid replenishment unit 44 through the replenishment pipe 42 is joined to the etching liquid flowing through the circulation pipe 38 as needed, so that the chemical liquid is replenished to the etching liquid 28 in the storage tank 30. It is configured.

  The supply pipe 32 is provided with a sampling pipe 46 branched in the middle. The sampling pipe 46 is connected to the concentration monitor 14 in a flow path. The concentration monitor 14 includes, for example, a sampling pump and an absorptiometer (not shown). Then, by operating the sampling pump every time a certain time, for example, 30 minutes, a part of the etching liquid flowing in the supply pipe 32 is taken out as a sampling liquid and introduced into the concentration monitor 14 through the sampling pipe 46. The The introduced sampling solution is guided into the quartz cell of the absorptiometer, and the absorbance at a specific wavelength, for example, 220 nm is measured. The measurement operation in the concentration monitor 14 is controlled by the personal computer 48 for concentration management, and the absorbance signal measured by the concentration monitor 14 is sent to the personal computer 48. Then, in the personal computer 48, the concentration of nitric acid in the sampling solution and hence in the etching solution flowing in the supply pipe 32 is calculated from the absorbance measured by the concentration monitor 14.

  Further, as schematically shown in FIG. 2, the storage tank 30 is turned on when the liquid level of the etching solution 36 in the storage tank 30 is equal to or higher than the highest position, and is turned off when the level is below the highest position. Upper liquid level sensor 50a such as a float switch and lower liquid such as a float switch that is turned on when the liquid level of the etching liquid 36 in the storage tank 30 is equal to or higher than the lowest position and turned off when the liquid level falls below the lowest position. A surface sensor 50b is attached. In FIG. 2, A indicates the entire capacity of the storage tank 30, and the newly replaced storage tank 30 is filled with the etching liquid for the entire capacity (A). In FIG. 2, B indicates the maximum capacity, and C indicates the minimum capacity. As an example of numerical values, A = 1200L, B = 1000L, and C = 250L.

  The personal computer 48 for density management is connected to the personal computer 52 for device management by the TCP / IP protocol, for example. An upper liquid level sensor 50a and a lower liquid level sensor 50b attached to the storage tank 30 are electrically connected to the personal computer 52 for device management. In the personal computer 52 for managing the apparatus, the amount of the etching solution per substrate that adheres to the processed substrate W and is taken out of the processing tank 18 together with the substrate W is set in advance and stored in the memory. deep. In the personal computer 52 for managing the apparatus, the number of substrates etched and taken out per substrate when all of the etching solution is updated to a new solution, that is, when the storage tank 30 is replaced with a new one. The amount of etching solution taken out is calculated from the set value of the amount, and information indicating the calculation result is sent from the personal computer 52 for device management to the personal computer 48 for concentration management. In the concentration management personal computer 48, the chemical solution to be replenished in the middle of the circulation path based on the information on the amount of the etchant carried out from the apparatus management personal computer 52 and the measured value of the nitric acid concentration in the etching solution. The control signal based on the calculation result is output from the personal computer 48 for concentration management and sent to the chemical solution replenishment unit 44. The chemical solution replenishment unit 44 replenishes the etching solution flowing through the circulation pipe 38 with an appropriate amount of required chemical liquid (high concentration nitric acid and acetic acid) through the replenishment pipe 42 by a control signal from the personal computer 48. Note that a storage tank 30 switching signal, a quantitative replenishment signal in the storage tank 30, a temperature signal of the storage tank 30, and the like are also sent from the apparatus management personal computer 52 to the concentration management personal computer 48.

Next, the concentration management operation of the etching solution in the etching process using the substrate processing apparatus described above will be described with reference to the flowchart shown in FIG.
An etching liquid is supplied from the storage tank 30 through the supply pipe 32 to the discharge nozzle 26 by the supply pump 34, the etching liquid is discharged from the discharge nozzle 26, and the etching liquid flowing down to the bottom of the processing tank 18 is recovered. 28 is collected in the storage tank 30 and the etching solution is circulated through these circulation paths. In this state, the substrates W are sequentially carried into the processing tank 18 one by one, and the etching solution is supplied from the discharge nozzle 26 to the surface of the substrate W while transporting the substrates W in the processing tank 18 in the horizontal direction. The processed substrate W is carried out of the processing bath 18.

  An etching solution (sampling solution) is introduced into the concentration monitor 14 from the supply pipe 32 through the sampling pipe 46 every 30 minutes from the start of the treatment, and the concentration of nitric acid in the etching solution is monitored by the concentration monitor. 14 and the measurement result is sent to the personal computer 48 for density management. At the same time, in the personal computer 52 for managing the apparatus, the number of processed wafers (N) that have been etched and carried out of the processing tank 18 so far and the amount of etching solution carried out per substrate (D) are as follows. The amount of etching solution taken out (D × N) is calculated from the set value, and the remaining amount (V) of the etching solution in the storage tank 30 is calculated from the equation V = B (maximum capacity of the storage tank 30) −D × N. The calculation result is sent to the personal computer 48 for density management. After the chemical solution is replenished into the circulation path, the remaining amount of tank (V) needs to be calculated from V = B + (total amount of chemical solution replenishment) −D × N in consideration of the total amount of the supplemented chemical solution. There is. Explaining with a numerical example, when the amount of etching solution taken per substrate (D) = 100 cc and the interval at which the substrates W are discharged from the processing tank 18 one minute, the processing time for 30 minutes The amount of etching solution taken out is 100 cc × 30 sheets = 3 L. Accordingly, the remaining tank capacity (V) after 30 minutes has elapsed since the start of processing is V = 1000L-3L = 997L, and the remaining tank capacity (V) after one hour has elapsed is V = 1000L-6L. = 994L.

  When the remaining tank capacity (V) is calculated, it is determined whether or not the remaining tank capacity (V) is less than the minimum capacity (C), and the remaining tank capacity (V) is less than the minimum capacity (C). (V <C), a predetermined amount of an etching solution (new solution) composed of a mixed solution of nitric acid, acetic acid, phosphoric acid and pure water is introduced by a solution charging unit (not shown) and stored in the storage tank 30. The etching solution 36 having the maximum capacity (B) is stored in the storage. It should be noted that this constant amount of new liquid may be automatically supplied whenever the lower liquid level sensor 50b changes from the ON state to the OFF in response to the signal change. On the other hand, when the tank remaining amount (V) is equal to or greater than the minimum capacity (C) (V ≧ C), the replenishment amount of the chemical solution is calculated. Next, an example of a method for calculating the replenishment amount will be described.

  When the aluminum film formed on the substrate is etched using an etching solution made of a mixed solution of nitric acid, acetic acid, phosphoric acid and pure water, the etching solution in the storage tank 30 is processed during the processing of the substrate. The amount of 36 gradually decreases. At this time, the concentrations of nitric acid and acetic acid in the etching solution respectively decrease, while the concentration of phosphoric acid in the etching solution slightly increases, and the proportion of pure water increases. Slightly decrease. Therefore, a necessary amount of high-concentration nitric acid and acetic acid is replenished in the circulation path based on the concentration of nitric acid measured by the concentration monitor 14 so that each concentration of nitric acid and acetic acid in the etching solution becomes a target concentration. Accordingly, the concentration control of the etching solution is performed based on the basic concept that the concentration of phosphoric acid in the etching solution is relatively lowered to reach the target concentration. In addition, since the ratio between the nitric acid concentration and the acetic acid concentration in the etching solution hardly changes even if the respective concentrations are reduced as the substrate is processed, in this embodiment, only the nitric acid concentration is measured by the concentration monitor 14. However, it is also possible to measure the concentration of acetic acid and calculate the replenishment amount of nitric acid based on the measurement result.

  Specifically, the maximum capacity (B) of the storage tank 30 is 100 L, and the initial concentration values of nitric acid, acetic acid, phosphoric acid and pure water in the etching solution are 5 w / v%, 10 w, respectively. / V%, 70 w / v%, and 15 w / v%, first, the total volume ratio (%) of each component, that is, how much volume each component occupies in 100 L of etching solution. calculate. Assuming that the specific gravity of nitric acid = 1.41, the specific gravity of acetic acid = 1.04, the specific gravity of phosphoric acid = 1.68, and the specific gravity of pure water = 1, the volume ratio of nitric acid = 5 / 1.41 from the concentration value / specific gravity. = 3.546%, volume ratio of acetic acid = 10 / 1.04 = 9.615%, volume ratio of phosphoric acid = 70 / 1.68 = 41.667%, volume ratio of pure water = 15/1 = 15 %, And the sum of the volume ratio of each component is 3.546 + 9.615 + 14.1667 + 15 = 69.828%. When the volume ratio of each component is converted to 100% and the total volume ratio (%) is obtained, the total volume ratio of nitric acid = (3.546 / 69.828) × 100 = 5.078%, the total volume ratio of acetic acid = (9.615 / 69.828) × 100 = 13.770%, Total volume ratio of phosphoric acid = (41.667 / 69.828) × 100 = 59.671%, Total volume ratio of pure water = ( 15 / 69.828) × 100 = 21.481%. Therefore, the volume of each component in the 100 L etching solution stored in the storage tank 30 in the initial stage is as follows: nitric acid: 5.078 L, acetic acid: 13.770 L, phosphoric acid: 59.671 L, pure water: 21.482 L It becomes.

  The etching process of the substrate W is sequentially performed, the amount of the etching solution 36 in the storage tank 30 is reduced, and the tank remaining amount (V) becomes 99 L. The concentration of nitric acid, acetic acid, phosphoric acid, and pure water in the etching solution is reduced. Assuming that the values become 4 w / v%, 8 w / v%, 72 w / v% and 16 w / v%, respectively, the volume ratio of nitric acid = 4 / 1.41 = 2.737%, the volume ratio of acetic acid = 8 / 1.04 = 7.692%, volume ratio of phosphoric acid = 72 / 1.68 = 42.857%, volume ratio of pure water = 16/1 = 16%, and the total volume ratio of each component is 2 837 + 7.692 + 42.857 + 16 = 69.386%. When the volume ratio of each component is converted to 100% to determine the total volume ratio (%), the total volume ratio of nitric acid = (2.837 / 69.386) × 100 = 4.089%, the total volume ratio of acetic acid = (7.692 / 69.386) × 100 = 11.086%, Total volume ratio of phosphoric acid = (42.857 / 69.386) × 100 = 61.766%, Total volume ratio of pure water = ( 16 / 69.386) × 100 = 23.059%. Accordingly, the volume of each component (hereinafter referred to as “total volume”) in the remaining amount of tank (V) = 99 L is as follows: nitric acid: 4.048 L, acetic acid: 10.975 L, phosphoric acid: 61.148 L, Pure water: 22.828L.

The total volume ratio of nitric acid in the initial state = 5.078% is set as the target nitric acid volume ratio, and the total volume ratio of acetic acid = 13.770% is set as the target acetic acid volume ratio. The replenishment amounts of the nitric acid solution and the acetic acid solution are respectively expressed by the following equations.
Target nitric acid volume ratio = [(total volume of nitric acid in etching solution + pure nitric acid volume of nitric acid to be replenished)
/ (Tank remaining amount + replenishment amount of nitric acid solution + replenishment amount of acetic acid solution)] x 100%
Target acetic acid volume ratio = [(total volume of acetic acid in etching solution + pure acetic acid volume of acetic acid solution to be supplemented)
/ (Tank remaining amount + replenishment amount of nitric acid solution + replenishment amount of acetic acid solution)] x 100%
Here, assuming that the nitric acid concentration in the nitric acid solution to be replenished (nitric acid + pure water, specific gravity = 1.41) is 70 w / v%, the volume ratio of nitric acid in the nitric acid solution = 70 / 1.41 = 49.645%, The volume ratio of pure water = 30/1 = 30%, and the total volume ratio is 49.645 + 30 = 79.645%. Then, when the volume ratio of nitric acid is converted to 100% and the total volume ratio (%) is obtained, (49.645 / 79.645) × 100≈62.3%. Further, when the acetic acid concentration of the acetic acid solution to be replenished (acetic acid + pure water, specific gravity = 1.04) is 99 w / v%, the volume ratio of acetic acid in the acetic acid solution = 99 / 1.04 = 95.192%, pure The volume ratio of water = 1/1 = 1%, and the total volume ratio is 95.192 + 1 = 96.192%. Then, when the volume ratio of acetic acid is converted to 100% and the total volume ratio (%) is obtained, (95.192 / 96.192) × 100≈99.0%.

When the replenishment amount of nitric acid solution is x and the replenishment amount of acetic acid solution is y, the above formulas are respectively
5.078 = [(4.048 + 0.623x) / (99 + x + y)] × 100
13.770 = [(10.975 + 0.990y) / (99 + x + y)] × 100
When x and y are obtained from both equations, x = 2.02L and y = 3.44L are obtained. That is, the etching solution circulating through the circulation path may be supplemented with 2.02 L of nitric acid solution and 3.44 L of acetic acid solution. As a result, the concentrations of nitric acid and acetic acid in the etching solution are increased, the concentration of phosphoric acid is decreased, the proportion of pure water is slightly increased, and the etching solution can be almost returned to the initial state.

Next, a method for appropriately resetting the amount of the processing liquid taken out per substrate in the calculation of the amount of the etching liquid taken out will be described with reference to the flowchart shown in FIG.
The etching solution 36 in the storage tank 30 remains on the substrate W during the processing of the substrate and is gradually reduced by being taken out of the processing tank 18 together with the substrate W. Since the temperature control function is usually equipped, the etching solution evaporates, and as a result, the etching solution is naturally lost in the circulation path. For this reason, even if chemical liquid is replenished in the circulation path as needed, the liquid level of the etching liquid in the storage tank 30 gradually decreases. Therefore, in calculating the amount of etching solution to be taken out, the amount of etching solution naturally lost in the circulation path is added to appropriately reset the amount of processing solution to be taken out per substrate.

  The etching process of the substrate is started in a state where the etching liquid 36 for the entire capacity (A) is stored in the storage tank 30, and the liquid level of the etching liquid in the storage tank 30 gradually decreases as the number of processed substrates increases. Then, it is assumed that the remaining amount (V) of the tank changes from the total capacity (A) to the maximum capacity (B) and from the maximum capacity (B) to the minimum capacity (C) (see FIG. 2). At the beginning of substrate processing, the amount of etching solution taken out is calculated using a value (D) preset and input as the amount of etching solution taken out per substrate. When the number of substrates processed increases and the upper liquid level sensor 50a provided in the storage tank 30 changes from ON to OFF (V <B), the apparatus management personal computer 52 receives the signal and An operation based on a calculation formula of D = [(A−B) + (total amount of chemicals replenished up to that time)] / (the number of substrates processed up to that time) is performed. The value of D calculated by this calculation is the amount of etching solution that remains on the substrate W during processing of the substrate and is taken out of the processing tank 18 together with the substrate W, and the amount of etching solution that is naturally lost by evaporation. It is included. The calculated value (D) is reset as the amount of etching liquid taken out per substrate. Further, when the number of processed substrates increases and the lower liquid level sensor 50b attached in the storage tank 30 changes from ON to OFF (V <C), the apparatus management personal computer 52 receives the signal and receives it. , D = [(AC) + (total amount of chemicals replenished up to that time)] / (number of substrates processed up to that time) is calculated. Then, the calculated value (D) is set again as the amount of etching liquid taken out per substrate. In this way, by resetting the amount (D) of the processing liquid taken out per substrate, the concentration management of the etching liquid can be performed more accurately.

  In the above-described embodiment, the example in which the nitric acid concentration in the etching solution is measured and nitric acid and acetic acid are supplemented to the etching solution circulating through the circulation path has been described. However, not only nitric acid but also the concentration of acetic acid may be measured. Moreover, the etching solution is not limited to the mixed solution of nitric acid, acetic acid, phosphoric acid and pure water, and the method of replenishing the chemical solution is not limited to that described in the above embodiment. In the above-described embodiment, the case where the substrate is etched has been described. However, the present invention can be widely applied to other substrate processing.

It is a figure which shows one example of embodiment of this invention and shows schematic structure of the substrate processing apparatus provided with the concentration management apparatus of the process liquid. It is a schematic diagram of the storage tank which is one of the components of the substrate processing apparatus shown in FIG. 6 is a flowchart for explaining an etching solution concentration management operation in an etching process using the substrate processing apparatus shown in FIG. 1. 1 is a diagram for explaining a method for resetting the amount of the processing liquid to be taken out per substrate in the calculation of the amount of the etching liquid to be taken when the concentration of the etching liquid is controlled using the substrate processing apparatus shown in FIG. It is a flowchart.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Etching process part 12 Apparatus main body 14 Concentration monitor 16 Etching liquid concentration management apparatus 18 Processing tank 24 Conveyance roller 26 Discharge nozzle 28 Etching liquid collection | recovery piping 30 Reservation tank 32 Etching liquid supply piping 34 Supply pump 36 Etching liquid 38 Circulation pipe 40 Circulation pump 42 Replenishment pipe 44 Chemical solution replenishment unit 46 Sampling pipe 48 Concentration control personal computer 50a Upper liquid level sensor 50b Lower liquid level sensor 52 Equipment management personal computer W Substrate A Total capacity of storage tank B Storage Maximum capacity of tank C Minimum capacity of storage tank

Claims (9)

The substrate is sequentially carried into the processing tank one by one, and the substrate is processed by circulating the processing liquid to the substrate while transporting the substrate in the horizontal direction in the processing tank to process the substrate, and the processed substrate is processed into the processing tank. In the substrate processing apparatus to be carried out from the inside,
A concentration measuring means for measuring the concentration of the processing liquid circulating through the circulation path;
A take-out amount calculating means for calculating the amount of the processing liquid that adheres to the substrate after processing and is taken out of the processing tank from the amount of processing liquid taken out per substrate and the number of processed substrates;
A replenishment amount for calculating the amount of the chemical solution to be replenished in the middle of the circulation path based on the concentration of the treatment liquid measured by the concentration measurement unit and the removal amount of the treatment liquid calculated by the carry-out amount calculation unit A calculation means;
Replenishment means for replenishing a chemical solution in the middle of the circulation path;
Control means for controlling the replenishment means to replenish the replenishment amount of the chemical solution calculated by the replenishment liquid amount calculation means in the middle of the circulation path;
A substrate processing apparatus comprising: In the calculation of the amount of processing liquid to be taken out by the take-out amount calculating means, the value of the amount of processing liquid to be taken out per substrate is added to the amount of processing liquid that is naturally lost in the circulation path due to evaporation of the processing liquid. The substrate processing apparatus according to claim 1, which is reset as appropriate. The substrate processing apparatus according to claim 1, wherein the processing liquid is an etching liquid made of a mixed solution of nitric acid, acetic acid, phosphoric acid and pure water, and the replenishing means replenishes high-concentration nitric acid and acetic acid, respectively. . The substrate is sequentially carried into the processing tank one by one, and the substrate is processed by circulating the processing liquid to the substrate while transporting the substrate in the horizontal direction in the processing tank to process the substrate, and the processed substrate is processed into the processing tank. In the substrate processing method carried out from the inside,
A concentration measurement step for measuring the concentration of the treatment liquid circulating through the circulation path;
A take-out amount calculating step of calculating the amount of the processing liquid that adheres to the substrate after processing and is taken out of the processing tank from the amount of processing liquid taken out per substrate and the number of processed substrates;
A replenishment amount for calculating the amount of the chemical solution to be replenished in the middle of the circulation path based on the concentration of the treatment liquid measured in the concentration measurement step and the removal amount of the treatment liquid calculated in the carry-out amount calculation step A calculation process;
A replenishment step of replenishing the replenishment amount of the chemical solution calculated in the replenishment amount calculation step in the middle of the circulation path;
A substrate processing method comprising: In the calculation of the amount of processing liquid to be taken out in the taking-out amount calculation step, the amount of processing liquid to be taken out per substrate is added to the amount of processing liquid that is naturally lost in the circulation path due to evaporation of the processing liquid. The substrate processing method according to claim 4, which is reset as appropriate. 6. The substrate processing method according to claim 4, wherein the processing liquid is an etching liquid made of a mixed solution of nitric acid, acetic acid, phosphoric acid and pure water, and replenishes nitric acid and acetic acid at high concentrations in the replenishing step, respectively. . In a processing liquid concentration management apparatus for managing the concentration of processing liquid supplied while being circulated to a substrate that is sequentially carried into the processing tank one by one and transported horizontally in the processing tank,
A concentration measuring means for measuring the concentration of the processing liquid circulating through the circulation path;
A take-out amount calculating means for calculating the amount of the processing liquid that adheres to the substrate after processing and is taken out of the processing tank from the amount of processing liquid taken out per substrate and the number of processed substrates;
A replenishment amount for calculating the amount of the chemical solution to be replenished in the middle of the circulation path based on the concentration of the treatment liquid measured by the concentration measurement unit and the removal amount of the treatment liquid calculated by the carry-out amount calculation unit A calculation means;
Replenishment means for replenishing a chemical solution in the middle of the circulation path;
Control means for controlling the replenishment means to replenish the replenishment amount of the chemical solution calculated by the replenishment liquid amount calculation means in the middle of the circulation path;
A treatment liquid concentration management apparatus comprising: In the calculation of the amount of processing liquid to be taken out by the take-out amount calculating means, the value of the amount of processing liquid to be taken out per substrate is added to the amount of processing liquid that is naturally lost in the circulation path due to evaporation of the processing liquid. The processing liquid concentration management apparatus according to claim 7, which is reset as appropriate. The treatment liquid according to claim 7 or 8, wherein the treatment liquid is an etching liquid composed of a mixed solution of nitric acid, acetic acid, phosphoric acid and pure water, and the replenishing means replenishes nitric acid and acetic acid at high concentrations. Concentration management device.

Images