TW201604324A - Apparatus for managing an etching solution, method for managing an etching solution and method for measuring concentration of components in an etching solution - Google Patents

Abstract

The present invention provides an apparatus for managing an etching solution, a method for managing an etching solution and a method for measuring concentration of components in an etching solution, in which the function of an oxalic acid based etching solution used as an etching solution is maintained and managed to keep approximately constant and solid particles are inhibited from precipitation. The solution provided by the present invention is a device or a method, comprising: a conductivity meter 17 which is used to measure the conductivity of the etching solution; a densimeter 18 which is used to measure the density of the etching solution; and a mechanism for controlling the transport of a replenishing solution, which controls the transport of the replenishing solution supplied into the etching solution depending on the relationship between the concentration of oxalic acid and the conductivity value of the etching solution and the result measured by the conductivity meter 17, and on the relationship between the concentration of solved metal and the density value of the etching solution and the result measured by the densimeter 18.

Description

Etching liquid management device, etching liquid management method, and method for measuring component concentration of etching liquid

The present invention relates to an etching liquid management device, an etching liquid management method, and a method for measuring a component concentration of an etching liquid, and more particularly to an etching liquid management device and etching for adjusting a concentration of an etching liquid whose concentration changes with time due to an etching process. Liquid management method and method for measuring component concentration of etching solution.

In the etching of the process of the semiconductor or the liquid crystal substrate, the etching liquid composed of the liquid appropriately conditioned by the etching target is circulated or stored in the etching bath, and is repeatedly used. When the etching target is an indium oxide-based transparent conductive film, for example, an indium tin oxide film (hereinafter referred to as "ITO film"), an indium zinc oxide film (hereinafter referred to as "IZO film"), or an indium gallium oxide film (hereinafter referred to as "IGO") When a film, or an oxide semiconductor film, for example, an In-Ga-Zn-O-based oxide semiconductor film containing indium, gallium or zinc (hereinafter referred to as "IGZO film"), etc., 3.4% or so of oxalic acid is often used. An aqueous solution of oxalic acid or a liquid to which an additive such as a surfactant is added (hereinafter, an etching solution containing oxalic acid as a main component is referred to as an "oxalic acid-based etching liquid").

Etching of ITO film and IZO film by such oxalic acid etching solution , IGO film or IGZO film, as the etching process proceeds, the indium or tin metal component is eluted from the ITO film into the etching solution, the indium or zinc metal component is eluted from the IZO film into the etching solution, and the indium is dissolved from the IGO film. The metal component of gallium is transferred into the etching solution, and the metal component of indium or gallium or zinc is eluted from the IGZO film into the etching solution. Therefore, as the etching process proceeds, the metal component eluted from the film to be etched accumulates in the etching liquid. However, the metal component accumulated in the etching liquid tends to suppress further elution of the metal component from the film to be etched, and if the etching liquid is not properly managed, the etching rate is lowered as the etching process proceeds. Deterioration.

Further, in the oxalic acid-based etching liquid, in the metal component eluted from the ITO film, the IZO film, the IGO film, or the IGZO film, in particular, the solubility of gallium or indium in the oxalic acid-based etching liquid is small, and it is easy to be a solid matter. Precipitate. Therefore, gallium or indium which is eluted into the etching liquid by the etching treatment and precipitated as a solid matter precipitates, and an etching residue or the like is generated, which causes deterioration in quality.

Further, as the etching process proceeds, the main component of the etching liquid is reduced by the etching reaction. Further, since the etching tank is sucked and exhausted so that the harmful gas does not leak to the outside, a part of the components such as moisture or acid are lost from the etching liquid due to the exhaust gas. Therefore, the liquid composition of the etching liquid changes with time and is unstable, and the dissolved metal increases, resulting in a decrease in the performance of the etching liquid.

In order to prevent deterioration of the quality of the solid matter, for example, Patent Document 1 below discloses a method or apparatus for removing and regenerating solid particles deposited in an etching solution by filtering an etching solution by a NF membrane (Nanofiltration Membrane). .

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2006-013158

However, in the method and apparatus described in Patent Document 1, the metal is recovered from the etching liquid after use, and the metal concentration of the etching liquid in use is not reviewed. Further, by providing the NF film, the deposited solid particles can be removed. However, since the metal concentration in the etching liquid is still high, the etching performance of the etching liquid is not improved.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an etching liquid management device, an etching liquid management method, and an etching method for maintaining and managing the performance of an oxalic acid-based etching liquid as an etching liquid while substantially fixing the precipitation of solid particles. Method for determining the concentration of a component of a liquid.

In order to achieve the above object, the present invention provides an etching liquid management device which is an etching liquid management device for managing an etching liquid, which is an etching solution containing oxalic acid and is used for containing at least one of indium, gallium or zinc. The etching of the etching film is characterized by comprising: a conductivity meter for measuring the conductivity value of the etching solution; a density meter for measuring the density value of the etching solution; and a correlation between the oxalic acid concentration of the etching solution and the conductivity value and The measurement result of the conductivity meter is such that the concentration of oxalic acid is within a concentration range which is correlated with the concentration of the indium concentration, the gallium concentration or the zinc concentration of the etching solution, and the concentration of the indium according to the etching solution. The correlation between the concentration of the gallium concentration and the zinc concentration and the density value and the measurement result of the densitometer, wherein at least one of the indium concentration, the gallium concentration, or the zinc concentration is equal to or less than the threshold of the managed concentration. A replenishing liquid delivery control means for controlling the delivery of the replenishing liquid to the etching liquid.

According to the present invention, in the oxalic acid concentration range including the management range of the oxalic acid concentration of the etching liquid, since the oxalic acid concentration of the etching liquid has a correlation with the electrical conductivity, if the correlation between the oxalic acid concentration and the electrical conductivity of the etching solution is obtained in advance, Then, based on the conductivity value of the etching liquid measured by the conductivity meter, the oxalic acid concentration for controlling the etching solution can be controlled between the concentration of the indium concentration, the gallium concentration, or the zinc concentration of the etching solution. The amount of replenishing liquid necessary for the concentration range of the correlation. Therefore, by adding the calculated liquid amount of the replenishing liquid to the etching liquid, the oxalic acid concentration of the etching liquid can be controlled between the density value of any one of the indium concentration, the gallium concentration, or the zinc concentration of the etching liquid. The concentration of oxalic acid is managed to a substantially fixed value within the concentration range of the correlation. Further, when indium is eluted from the film to be etched into the etching liquid, the indium concentration range in which the concentration of the oxalic acid is managed within a specified concentration range and the concentration of the indium concentration of the etching solution is included is determined by the indium concentration and density of the etching solution. In the correlation, if the correlation between the indium concentration and the density of the etching solution is obtained in advance, the concentration for controlling the indium concentration of the etching solution to be within the management range can be calculated from the density value of the etching liquid measured by the densitometer. The amount of the replenishing liquid required for the concentration below the upper limit (hereinafter referred to as "pre-limit"). Therefore, by adding the calculated liquid amount of the replenishing liquid to the etching liquid, the indium concentration of the etching liquid can be made equal to or less than the threshold value. Therefore, by Since the concentration of indium dissolved in the etching solution can be saturated and managed, it is possible to prevent solid particles derived from indium from being deposited in the etching liquid. Further, since the oxalic acid concentration of the etching liquid can be managed to be substantially constant and the solubility of indium in the etching liquid is maintained, the etching performance of the etching liquid can be maintained in a good state. Further, as in the etching of the IGZO film, when not only indium but also gallium or zinc is eluted from the film to be etched into the etching liquid, similarly, the indium concentration, the gallium concentration, or the zinc concentration and the density between the etching liquids are obtained in advance. According to the correlation value, the replenishing liquid of the necessary liquid amount is supplied to the etching liquid according to the density value of the etching liquid measured by the densitometer, and the indium concentration of the etching liquid can be made not only the gallium concentration or the zinc concentration of the etching liquid but also the etching solution. Since it is less than the threshold value, precipitation of solid particles derived from gallium or zinc can be prevented, and the etching performance of the etching liquid can be maintained in a good state.

In order to achieve the above object, the present invention provides an etching liquid management device which is an etching liquid management device for managing an etching liquid, which is an etching solution containing oxalic acid and is used for containing at least one of indium, gallium or zinc. The etching of the etching film is characterized by comprising: a conductivity meter for measuring the conductivity value of the etching solution; a density meter for measuring the density value of the etching solution; and a conductivity value measured by the conductivity meter and measured by a densitometer a density value, a component concentration calculation means for calculating an oxalic acid concentration of the etching solution, and at least one of an indium concentration, a gallium concentration, or a zinc concentration of the etching solution by multivariate analysis; and The calculated oxalic acid concentration of the etching liquid is within the range of the controlled concentration, and the supply of the etching liquid to the etching liquid is controlled so that at least one of the indium concentration, the gallium concentration, or the zinc concentration of the etching liquid becomes equal to or less than the threshold value of the controlled concentration. Replenishment fluid delivery Send control means.

According to the present invention, at least one of the oxalic acid concentration of the etching liquid and the indium concentration, the gallium concentration, or the zinc concentration of the etching liquid can be accurately calculated by the multivariate analysis method from the conductivity value and the density value of the etching liquid. Further, depending on the oxalic acid concentration of the etching solution and at least one of the indium concentration, the gallium concentration, or the zinc concentration of the etching solution, the oxalic acid concentration of the etching solution is within a controlled concentration range, and the indium concentration of the etching solution is used. At least one of the gallium concentration and the zinc concentration is equal to or less than the threshold value, and the replenishing liquid of the necessary liquid amount is supplied to the etching liquid. Therefore, the oxalic acid concentration of the etching solution can be managed to a substantially fixed value, since the etching liquid can be managed in an indium concentration, gallium in a manner in which solid particles derived from indium, gallium derived or zinc-derived are not precipitated in the etching liquid. Since the concentration or the zinc concentration is used, the etching performance of the etching solution can be maintained in a good state.

In order to achieve the above object, the present invention provides an etching liquid management method for managing an etching liquid etchant containing an etchant solution of oxalic acid and for containing at least one of indium, gallium or zinc. The etching of the etching film is characterized by: a conductivity measuring step of measuring a conductivity value of the etching liquid; a correlation between the oxalic acid concentration and the conductivity value of the etching solution and a measurement result of the conductivity measuring step, and an oxalic acid concentration In the concentration range in which the concentration of the indium concentration, the gallium concentration, or the zinc concentration of the etching solution is correlated with the density value, the oxalic acid concentration for controlling the supply of the replenishing liquid supplied to the etching liquid is controlled by the replenishing liquid. a step of measuring a density value of a density value of an etching solution in which a concentration of oxalic acid is controlled within a concentration range by using a supplemental liquid transport control step of oxalic acid concentration; and, depending on an indium concentration and a gallium concentration of the etching solution Or the relationship between the concentration of the zinc concentration and the density value and the measurement result of the density measuring step, such that at least one of the indium concentration, the gallium concentration, or the zinc concentration of the etching solution becomes below the threshold of the managed concentration. The metal concentration for controlling the supply of the replenishing liquid supplied to the etching liquid is controlled by the replenishing liquid.

According to the present invention, in the oxalic acid concentration range including the management range of the oxalic acid concentration of the etching solution, since the oxalic acid concentration of the etching liquid has a correlation with the electrical conductivity, if the correlation between the oxalic acid concentration of the etching liquid and the electrical conductivity is obtained in advance, The oxalic acid concentration for controlling the etching solution can be calculated between the density value of any one of the indium concentration, the gallium concentration, or the zinc concentration of the etching solution, based on the conductivity value of the etching liquid measured through the conductivity measuring step. The amount of replenishing liquid necessary for the concentration range of the relevant relationship. Therefore, the oxalic acid concentration of the etching liquid and the etching liquid supplied to the etching liquid and the etching liquid are controlled to have a correlation with the density value of any one of the indium concentration, the gallium concentration, or the zinc concentration of the etching liquid. The concentration of oxalic acid can be managed to a substantially fixed value within the concentration range. Further, when indium is eluted from the film to be etched into the etching liquid, the indium concentration range in which the concentration of the oxalic acid is managed within a specified concentration range and the concentration of the indium concentration of the etching solution is included is determined by the indium concentration and density of the etching solution. Correlation, if the correlation between the indium concentration and the density of the etching solution is obtained in advance, the indium concentration of the etching solution can be calculated to be below the threshold value based on the density value of the etching liquid measured through the density measuring step. The amount of liquid of the replenishing liquid necessary for the concentration. Therefore, by adding the calculated liquid amount of the replenishing liquid to the etching liquid, the indium concentration of the etching liquid can be made equal to or less than the threshold value. Therefore, since the dissolved indium in the etching solution is not allowed Since the concentration is saturated and managed, it is possible to prevent solid particles derived from indium from being deposited in the etching liquid. Further, since the oxalic acid concentration of the etching liquid can be managed to be substantially constant and the solubility of indium in the etching liquid is maintained, the etching performance of the etching liquid can be maintained in a good state. Further, as in the etching of the IGZO film, when not only indium but also gallium or zinc is eluted from the film to be etched into the etching liquid, similarly, the correlation between the gallium concentration of the etching liquid or the density of the zinc concentration is obtained in advance, according to The replenishment liquid of the necessary liquid amount is supplied to the etching liquid by the density value of the etching liquid measured by the density measuring step, and since the gallium concentration or the zinc concentration of the etching liquid can be equal to or less than the threshold value, it is possible to prevent the source of gallium or the source from being removed. The deposition of solid particles of zinc maintains the etching performance of the etching solution in a good state.

In order to achieve the above object, the present invention provides an etching liquid management method for managing an etching liquid etchant containing an etchant solution of oxalic acid and for containing at least one of indium, gallium or zinc. The etching of the etching film is characterized by: a conductivity measuring step of measuring a conductivity value of the etching liquid; a density measuring step of measuring a density value of the etching liquid; and a conductivity value measured by the conductivity measuring step and a density measurement a density value measured in the step, a component concentration calculation step of calculating an oxalic acid concentration of the etching solution, and at least one of an indium concentration, a gallium concentration, or a zinc concentration of the etching solution by a multivariate analysis method; and The calculated oxalic acid concentration of the etching liquid is within the range of the controlled concentration, and the supply of the etching liquid to the etching liquid is controlled so that at least one of the indium concentration, the gallium concentration, or the zinc concentration of the etching liquid becomes equal to or less than the threshold value of the controlled concentration. The replenishing liquid delivery control step of the delivery of the replenishing liquid.

According to the present invention, the oxalic acid concentration of the etching solution and the indium concentration of the etching solution can be accurately calculated by the multivariate analysis method from the conductivity value and the density value of the etching liquid measured by the conductivity measuring step and the density measuring step. At least one of a gallium concentration or a zinc concentration. Further, depending on the oxalic acid concentration of the etching solution and at least one of the indium concentration, the gallium concentration, or the zinc concentration of the etching solution, the oxalic acid concentration of the etching solution is within a controlled concentration range, and the indium concentration of the etching solution is used. At least one of the gallium concentration or the zinc concentration is equal to or less than the threshold value, and the replenishing liquid of the necessary liquid amount is supplied. Therefore, the oxalic acid concentration of the etching solution can be managed to a substantially fixed value, since the etching liquid can be managed in an indium concentration, gallium in a manner in which solid particles derived from indium, gallium derived or zinc-derived are not precipitated in the etching liquid. Since the concentration or the zinc concentration is used, the etching performance of the etching solution can be maintained in a good state.

In order to achieve the above object, the present invention provides a method for measuring a component concentration of an etching solution, comprising: a conductivity measuring step of measuring a conductivity value of an etching solution, wherein the etching solution contains an etchant of oxalic acid and is used for containing indium, Etching of an etched film of at least one of gallium or zinc; a density measuring step of measuring a density value of the etching solution; and a density value measured by the conductivity measuring step and a density value measured by the density measuring step A component concentration calculation step of calculating at least one of an oxalic acid concentration of the etching solution and an indium concentration, a gallium concentration, or a zinc concentration of the etching solution by a multivariate analysis method.

According to the present invention, since the conductivity value and the density value of the etching liquid measured by the conductivity measuring step and the density measuring step are obtained, the oxalic acid concentration of the etching solution and the etching liquid are calculated by multivariate analysis. The component concentration calculation step of at least one of the indium concentration, the gallium concentration, or the zinc concentration can accurately measure at least one of the oxalic acid concentration of the etching liquid and the indium concentration, the gallium concentration, or the zinc concentration of the etching liquid.

According to the etching liquid management apparatus, the etching liquid management method, and the component concentration measuring method of the etching liquid of the present invention, an appropriate amount of the replenishing liquid can be supplied to the etching liquid based on the measured concentration value or physical property value of each component. The oxalic acid concentration of the etchant can be frequently managed to a substantially fixed value over the range of concentrations being managed. Further, the concentration of the metal component such as indium, gallium, and zinc dissolved in the etching solution can be constantly managed below the threshold of the concentration to be managed. Therefore, the etching performance of the etching liquid can be prevented from being lowered, and the liquid property of the etching liquid can be immobilized while the liquid life becomes long. Further, precipitation of solid particles derived from the metal component can be suppressed, and the adhesion of the solid particles to the film to be etched can be suppressed, and the quality can be lowered.

Further, by constantly maintaining the etching liquid at the most suitable liquid property, the downtime of the production apparatus can be reduced, and productivity can be improved. Further, it is possible to prevent the occurrence of etching residue caused by the deposition of dissolved metal as the etching process proceeds, and it is possible to improve the yield of the product.

1‧‧‧etching tank

2‧‧‧Overflow trough

3‧‧‧Level gauge

4‧‧‧ etching chamber cover

5‧‧‧Roller conveyor

6‧‧‧Substrate

7‧‧‧etching liquid sprayer

8‧‧‧ Liquid pump

9‧‧‧Filter

10,12‧‧‧Circulation pipeline

11‧‧‧Circulating pump

17‧‧‧Electrometer

18‧‧‧density meter

20‧‧‧Liquid discharge pump

21‧‧‧ Etching stock solution supply tank ((replenishment liquid) supply tank)

22‧‧‧ etching new liquid supply tank ((replenishment liquid) supply tank)

23‧‧‧oxalic acid stock solution supply tank ((replenishment liquid) supply tank)

24‧‧‧Pipe

25, 26, 27‧‧‧ flow control valve

28‧‧‧Flow regulating valve (pure water supply valve)

29‧‧‧Confluence pipeline

30‧‧‧ computer

31‧‧‧Sampling piping

32‧‧‧Sampling pump

33‧‧‧Reflow piping

100‧‧‧etching mechanism

A‧‧‧ etching processing department

B‧‧‧ Etching liquid circulation department

D‧‧‧Replenishment Supply Department

E‧‧‧Determination Department

Fig. 1 is a system diagram of an etching processing mechanism including an etching liquid management device according to a first embodiment of the present invention.

Fig. 2 is a graph showing the relationship between the concentration of oxalic acid and the conductivity of the etching solution.

Fig. 3 is a graph showing the relationship between the dissolved metal concentration of the etching solution and the density.

[Formation of the Invention]

Hereinafter, suitable embodiments of the present invention will be described in detail with reference to the drawings. However, the shapes of the constituent devices described in the above embodiments, the relative arrangement thereof, and the like, are not intended to limit the scope of the present invention to the only examples, and are merely illustrative examples.

[First Embodiment]

Fig. 1 is a system diagram of an etching processing mechanism 100 including an etching liquid management device according to a first embodiment of the present invention.

The etching liquid management apparatus according to the present embodiment is mainly applied to an etching treatment for etching a metal film or a metal compound film containing an etching film of at least one of indium, gallium or zinc, and the etching liquid is an aqueous solution containing oxalic acid. The management of the oxalic acid concentration and the dissolved metal concentration of the etching solution is important. The system diagram of Fig. 1 includes an etching treatment unit A for storing an etching treatment tank 1 that is connected to an etching liquid management device of the present invention and that maintains an etching liquid having a concentration of a specified component, and is stored in an etching treatment tank. The etchant circulation portion B in which the etching liquid in 1 is circulated and stirred, the replenishing liquid supply tanks 21 to 23 in which various replenishing liquids are stored, and the flow regulating valves 25 to 28 which are controllable switches attached to the replenishing liquid supply line are supplemented. The liquid supply unit D measures a measurement unit E that measures the conductivity or density of the etching liquid in relation to the oxalic acid concentration or the dissolved metal concentration of the etching solution, and a computer 30 that performs various calculations or controls. Further, the etching liquid management device of the present invention is used in the measuring unit E, the computer 30, and the replenishing liquid supply unit D. The flow regulating valves 25, 26, 27, 28 are formed.

<etching processing unit A>

The etching treatment portion A is for ejecting an etching liquid onto the surface of the substrate to be transported, thereby etching the surface of the substrate.

As shown in Fig. 1, the etching processing unit A includes an etching treatment tank for storing an etching liquid, an overflow tank for receiving an etching liquid overflowed from the etching processing tank 1, and an etching liquid for measuring the etching liquid in the etching processing tank 1. The liquid level level gauge 3, the etching chamber cover 4, the roll conveyor 5 for transporting the substrate 6 disposed above the etching processing tank 1, the etching liquid sprayer 7, and the like.

The etching treatment tank 1 and the etching liquid atomizer 7 are connected by a circulation line 10 in which a liquid supply pump 8 and a filter 9 for removing fine particles of an etching liquid are provided in the middle.

When the liquid feeding pump 8 is operated, the etching liquid stored in the etching processing tank 1 is supplied to the etching liquid atomizer 7 via the circulation line 10, and is ejected from the etching liquid atomizer 7. Thereby, the surface of the substrate 6 conveyed via the roller conveyor 5 is etched. Further, the surface of the substrate 6 is covered with a metal film or a metal compound film and a resist film.

The etching liquid after the etching is dropped into the etching treatment tank 1 and stored again, and is supplied to the etching liquid atomizer 7 via the circulation line 10 in the same manner as described above, and is then ejected from the etching liquid atomizer 7.

<etching liquid circulation part B>

The etching liquid circulation portion B is mainly used to circulate and stir the etching liquid stored in the etching treatment tank 1.

The bottom of the etching treatment tank 1 is connected to the side portion of the etching treatment tank 1 by a circulation line 12 in which the circulation pump 11 is provided on the way. If When the circulation pump 11 is operated, the etching liquid stored in the etching treatment tank 1 is circulated through the circulation line 12. The etching liquid is returned from the side of the etching treatment tank 1 to the etching treatment tank 1 via the circulation line 12, and the stored etching liquid is stirred.

Further, when the replenishing liquid flows into the circulation line 12 through the merging line 29, the inflowing replenishing liquid is supplied into the etching treatment tank 1 while being mixed with the etching liquid circulating in the circulation line 12.

<Replenishing liquid supply unit D>

The replenishing liquid supply unit D is for supplying the replenishing liquid to the etching treatment tank 1 . As the replenishing liquid, there are an etching stock solution, an etching new liquid, an oxalic acid raw liquid, pure water, and an etching regeneration liquid. Since these are not necessarily completely required, the most suitable replenishing liquid and supply device are selected in accordance with the composition of the etching liquid, the degree of concentration change, equipment conditions, operating conditions, and the state of acquisition of the replenishing liquid.

The replenishing liquid supply unit D includes an etching stock solution supply tank 21 for storing each replenishing liquid, an etching new liquid supply tank 22, an oxalic acid raw material supply tank 23, and an existing piping for supplying pure water. However, the supply tanks 21 to 23 are only an example, and the number of the supply tanks or the type of the replenishing liquid of the contents thereof may be appropriately selected in accordance with the above-described conditions and the like.

The liquid supply piping for supplying the replenishing liquid from each of the supply tanks 21 to 23 and the existing piping for supplying pure water are provided with flow rate adjusting valves 25 to 28 that are controlled by the switch of the computer 30, and are collected before the flow rate adjusting valve. The flow line 29 is connected to the circulation line 12. Furthermore, in the present embodiment, the computer 30 and the flow rate adjusting valves 25 to 28 correspond to the replenishing liquid delivery control means. Each of the supply tanks 21 to 23 is connected to a pipe 24 for supplying N ₂ gas, and each of the supply grooves 21 to 23 is pressurized by the N ₂ gas supplied from the pipe 24 . Therefore, if at least one of the flow regulating valves 25 to 28 is opened by the control of the computer 30, the replenishing liquid corresponding to the controlled flow regulating valve passes through the liquid supply line, the confluent line 29, and the circulation line. 12 is pressurized and transported into the etching treatment tank 1. Further, in the switching control of the flow rate adjusting valves 25 to 28, a controller such as a sequencer may be used instead of the computer 30.

For example, when the flow rate adjusting valve 25 (etching stock solution valve) is opened by the control of the computer 30, the etching stock solution stored in the etching stock solution supply tank 21 is passed through the liquid supply line, the joining line 29, and the circulation line 12. It is pressurized and sent to the etching treatment tank 1. Similarly, when the flow rate adjustment valve 28 (pure water supply valve) is opened by the control of the computer 30, the pure water from the existing piping is supplied through the liquid supply line, the junction line 29, and the circulation line 12. It is supplied into the etching treatment tank 1.

Since each flow regulating valve is adjusted to flow a specified amount of liquid when it is opened, the time for opening each flow regulating valve can be controlled by the computer 30, and only the necessary amount of necessary replenishing liquid can be replenished.

In the first drawing, each of the replenishing liquids flows into the circulation line 12 through the respective liquid supply piping and the joining line 29, and is supplied into the etching treatment tank 1 while being mixed with the etching liquid circulating in the circulation line 12. The replenishing method of the replenishing liquid is not limited thereto, and the replenishing liquid may be replenished by directly connecting each of the liquid feeding pipes to the circulation line 12 or the etching treatment tank 1 without passing through the joining line 29.

Furthermore, an etchant to be stored in the etching bath 1 is provided The liquid discharge pump 20 is discharged. This is used when the initial cleaning or liquid exchange in the etching treatment tank 1 is used.

In the replenishing liquid supply unit D, the replenishing liquid is replenished based on the oxalic acid concentration of the etching liquid obtained from the conductivity value measured by the conductivity meter 17 of the measuring unit E described below. Further, the replenishment liquid is replenished based on the indium concentration, the gallium concentration, or the zinc concentration of the etching liquid obtained from the density value measured by the densitometer 18. Regarding the oxalic acid concentration, the computer 30 compares the value of the oxalic acid concentration of the obtained etching liquid with the value of the oxalic acid concentration to be managed, and if the oxalic acid concentration is insufficient, the oxalic acid concentration is increased, and if the oxalic acid concentration is too large, the oxalic acid concentration is lowered. In one embodiment, at least one of the etching stock solution, the etching new liquid, the etching regeneration liquid, the oxalic acid raw liquid, and the water is supplied as a replenishing liquid, and the oxalic acid concentration is controlled to a substantially constant value within the controlled concentration range. Further, regarding the indium concentration, the gallium concentration, or the zinc concentration of the etching solution, the computer 30 compares the obtained value of the indium concentration, the gallium concentration, or the zinc concentration with the threshold value of the managed indium concentration, gallium concentration, or zinc concentration, when indium When the concentration, the gallium concentration, or the zinc concentration is equal to or greater than the threshold value, at least one of the etching stock solution, the etching new liquid, the etching regeneration liquid, the oxalic acid raw liquid, and the water is supplied as a replenishing liquid to reduce the indium concentration, the gallium concentration, or the zinc concentration. The indium concentration, the gallium concentration, or the zinc concentration is controlled below the threshold of the managed concentration. In addition, the "replenishment liquid" in the present invention is a liquid used for adjusting the components of the etching liquid, and is a general term for liquids such as etching stock solution, etching new liquid, etching regeneration liquid, oxalic acid raw liquid, and water. The replenishing liquid system may mix a plurality of liquids before replenishing, or may separately replenish a plurality of liquids separately.

Further, the control of the concentration of the etching liquid is not limited to The control of comparing the oxalic acid concentration and the indium concentration, the gallium concentration or the zinc concentration with the management value may also use the integral value of the obtained oxalic acid concentration over time according to the conductivity value of the etching liquid frequently monitored by the conductivity meter 17. Or a differential value, or a combination of such controls. By enabling the control device thus controlled to operate in conjunction with the conductivity meter 17 and the flow rate adjusting valves 25 to 28, the oxalic acid concentration of the etching liquid can be controlled within a specified range in accordance with the oxalic acid concentration of the etching liquid. Similarly, regarding the metal concentration, the integrated value or the differential value of the obtained indium concentration, the gallium concentration, or the zinc concentration may be used according to the density value of the etching liquid frequently monitored by the densitometer 18, or may be The appropriate combination has such control. By enabling the control device thus controlled to operate in conjunction with the densitometer 18 and the flow regulating valves 25-28, the metal concentration of the etching solution can be controlled to the managed threshold according to the indium concentration, the gallium concentration or the zinc concentration of the etching solution. Below the value.

Further, in the above, the replenishing liquid is adjusted according to at least one of the oxalic acid concentration of the etching liquid, the indium concentration of the etching liquid, the gallium concentration, or the zinc concentration, and may be passed through the conductivity meter 17 and the densitometer 18. The measured conductivity value and the density value are within a range of the conductivity value corresponding to the concentration range in which the oxalic acid concentration is managed, and at least one of the indium concentration, the gallium concentration, or the zinc concentration is equal to the managed threshold value. Below the density value, at least one of oxalic acid concentration and indium concentration, gallium concentration or zinc concentration is controlled.

<Measurement section E>

The measuring unit E is for measuring at least one of the oxalic acid concentration of the sampled etching liquid, the concentration of dissolved indium in the etching solution, the concentration of gallium, or the concentration of zinc.

In the measurement unit E, the sampling pump 32 for sampling the etching liquid from the circulation line 10 is connected to the sampling pipe 31, and includes a conductivity meter 17 for measuring the conductivity value of the sampled etching liquid, and is used for the measurement unit. The density meter 18 of the density value of the sampled etching liquid returns the reflux pipe 33 to return the sampled etching liquid. Further, the sampling pipe 31 and the return pipe 33 may be directly connected to the etching treatment tank 1.

The oxalic acid concentration of the etching solution is related to the conductivity value in the range of the oxalic acid concentration including the concentration range managed therein, so that the correlation between the oxalic acid concentration and the conductivity value of the etching solution can be obtained in advance, and if the correlation is utilized, For the relationship, the oxalic acid concentration can be obtained from the conductivity value measured by the conductivity meter 17. Further, the dissolved metal concentration of the etching solution is related to the density value in the range of the dissolved metal concentration including the management range of the dissolved metal concentration of the etching liquid in which the concentration of the oxalic acid is controlled within the specified concentration range, so that the etching can be performed in advance. The correlation between any one of the dissolved indium concentration, the concentration of gallium, or the concentration of zinc in the liquid, and if the correlation is used, the concentration of indium can be obtained from the density value measured by the densitometer 18. At least one of a gallium concentration or a zinc concentration.

Further, when a plurality of metals are dissolved in the etching solution, for example, indium and tin are eluted when the ITO film is etched, indium and zinc are eluted when the IZO film is etched, indium and gallium are eluted when the IGO film is etched, and indium and gallium are etched when the IGZO film is etched. Zinc is eluted, but in this case, the density value of the etching solution is determined by the concentration of indium which is a large atomic amount among the metal components. Further, the ratio of the solubility of other metal components in the etching solution can be naturally understood by the film of the film to be etched, and the case of the ITO film is indium oxide: tin oxide is about 90 to 95:10 to 5% by mass, IGZO The condition of the film is indium: gallium: zinc=1 : 1:1 mol or so. Therefore, when a plurality of metals are dissolved in the etching solution, the concentration of the dissolved indium in the etching solution can be determined by measuring the density value, and the other metal can be obtained from the film composition.

The conductivity meter 17 and the density meter 18 are connected to the computer 30, and transmit measurement results and the like.

The correlation between the oxalic acid concentration of the etching solution and the conductivity value measured by the conductivity meter 17 may be a single corresponding relationship, and a simple function such as a polynomial, an exponential function, a logarithmic function or the like is preferably approximated. The relationship of performance is better for a straight line relationship.

Generally, since the conductivity value of the etching liquid continuously and smoothly changes with the change of the oxalic acid concentration, the conductivity value also shows a continuous gentle change with time as the oxalic acid concentration of the etching liquid shows a gentle change with time. Therefore, in the oxalic acid concentration range including the management range of the oxalic acid concentration of the etching liquid, the correlation relationship between the conductivity value of the etching liquid and the oxalic acid concentration can be obtained as described above. Further, when this correlation is used, the oxalic acid concentration of the etching solution can be obtained from the conductivity value of the etching liquid measured by the conductivity meter 17.

Further, the correlation between the concentration of indium dissolved in the etching solution, the concentration of gallium or the concentration of zinc and the density value measured by the densitometer 18 may be a single correspondence relationship, and preferably a polynomial, The relationship between the exponential function, the logarithm function, and the like is approximated by a linear function.

Generally, since the density value of the etching liquid continuously and smoothly changes with the change of the dissolved metal concentration, the density value also shows continuous gentleness as the dissolved metal concentration of the etching liquid shows a gentle change with time. Change over time. Therefore, in the concentration range of the concentration of dissolved indium in the inclusion etching solution, the concentration of dissolved gallium or the concentration of zinc, the density value of the etching solution and the concentration of indium, gallium or zinc can be used. The correlation between any of the concentrations is as described above. Further, when this correlation is used, at least one of the concentration of the dissolved indium in the etching solution, the concentration of gallium, or the concentration of zinc can be obtained from the density value of the etching liquid measured by the densitometer 18.

The dissolved metal concentration value thus obtained is compared with the management value, and the supply amount of the replenishing liquid is controlled by the replenishing liquid delivery control means so that the dissolved metal concentration value becomes equal to or less than the threshold value of the managed concentration.

The value of the dissolved metal concentration is preferably controlled so that the dissolved metal concentration becomes a dissolved metal concentration value below the upper limit of the managed concentration range. Further, the value of the concentration of the dissolved metal is preferably set in advance, but may be appropriately adjusted during the operation of the apparatus.

[Method for determination of oxalic acid concentration and dissolved metal concentration]

Next, an example of a method of measuring the concentration of oxalic acid and the concentration of dissolved metal in the etching solution will be described. In the following description, the acid portion is oxalic acid, the management value of the oxalic acid concentration of the etching solution is 3.4%, and the dissolved metal in the etching solution is indium. However, the present invention is not limited. This is limited by other materials and other management values.

As the etching liquid, a 3.4% aqueous solution of oxalic acid used for etching an oxide semiconductor film such as an ITO film, an IZO film, an IGO film, or the like, or an oxide semiconductor film such as an IGZO film is used as the etching liquid, and indium is used as a dissolved metal to prepare a solution. Simulate the sample solution. The conductivity and density of the simulated sample solution were measured, and the correlation with the concentration of oxalic acid and the concentration of indium was investigated.

The preparation of the sample was carried out by weighing a specified amount of oxalic acid dihydrate and indium oxide, and dissolving in pure water to prepare samples of various concentrations. Table 1 shows the relationship between the oxalic acid concentration (wt%) and the indium concentration (ppm), and the electrical conductivity (mS/cm) and the density (g/cm ³ ). The sample system is prepared with 10 types of A series samples (A-1~A-10), 10 types of B series samples (B-1~B-10), and 14 types of C series samples (C-1~C-14). Conductivity and density. The C series samples are samples that mimic the condition that the oxalic acid concentration is managed at around 3.4%. Further, the oxalic acid concentration and the indium concentration of the sample were calculated from the weighing value of the reagents weighed at the time of sample preparation. Further, the concentration of oxalic acid is converted into the concentration of the anhydrate. The temperature at the time of measurement was that the measurement temperature of all the samples was 25 °C.

Figures 2 and 3 plot the results of Table 1 as a graph. Fig. 2 is a graph in which the measurement results of the conductivity values of all the samples are plotted in a coordinate system in which the horizontal axis represents the oxalic acid concentration (wt%) of the sample and the vertical axis represents the conductivity (mS/cm) of the sample. . It can be clearly confirmed from Fig. 2 that the concentration of oxalic acid and the conductivity of the aqueous solution of oxalic acid in which indium is dissolved are linearly closed. system. Therefore, based on this relationship, it was confirmed that the oxalic acid concentration of the aqueous oxalic acid solution was obtained by detecting the conductivity of the aqueous oxalic acid solution in the range of the oxalic acid concentration obtained by the linear relationship.

Fig. 3 is a graph in which the measurement results of the density of all the samples in the coordinate system in which the horizontal axis represents the indium concentration (ppm) of the sample and the vertical axis represents the density (g/cm ³ ) of the sample. As is apparent from Fig. 3, in the C series samples in which the oxalic acid concentration was managed to a substantially fixed value, the indium concentration and the density were linear. Therefore, based on this relationship, it was confirmed that the concentration of indium dissolved in the aqueous oxalic acid solution was obtained by detecting the density of the aqueous oxalic acid solution when the oxalic acid concentration was managed to be substantially fixed.

As a result, the inventors discovered by experiment that there is a linear relationship between the oxalic acid concentration of the etching solution and the conductivity of the etching liquid, and it is found that the etching can be determined by detecting the conductivity of the etching liquid according to the linear relationship. The acid concentration of the liquid.

Moreover, the inventors have found through experiments that when the concentration of oxalic acid is managed to be substantially fixed, there is a linear relationship between the dissolved metal concentration of the etching solution and the density of the etching solution, and it is found that the linear relationship is detected and detected. The density of the etching solution determines the dissolved metal concentration of the etching solution.

The management range of oxalic acid concentration is within ±0.1% of the management target value (3.4% in Table 1), preferably within ±0.05% of the management target value. By setting the concentration of oxalic acid to a substantially constant value, the change in the density value due to the influence of the change in the concentration of oxalic acid can be suppressed, so that the change in the concentration of indium can be correlated with the change in the density of the etching solution. Therefore, the concentration of dissolved indium in the solution can be accurately determined.

Based on such knowledge, in the measuring unit E, by measuring the conductivity of the etching liquid, the oxalic acid concentration of the etching liquid can be obtained from the linear relationship between the oxalic acid concentration of the etching liquid and the electrical conductivity. Further, by detecting the density of the etching liquid, the dissolved metal concentration of the etching liquid can be obtained from the linear relationship between the dissolved metal concentration and the density of the etching liquid.

Further, in Fig. 1, the conductivity meter 17 and the densitometer 18 are provided separately from the etching processing tank 1, and the etching liquid is sampled through the sampling pipe 31, and is set by the measuring unit of the conductivity meter 17 and the density meter 18. In the etching treatment tank 1, the acid concentration and the dissolved metal concentration of the etching liquid are obtained.

<computer 30>

The computer 30 is electrically connected to the conductivity meter 17, the density meter 18, and the flow rate adjusting valves 25-28. The computer 30 is controlled by issuing an operation command to the connected device, and also obtains measurement data such as the concentration of oxalic acid or the concentration of dissolved indium in the etching solution, the concentration of gallium, or the concentration of zinc, and the like. Send and receive information. In addition, it has various functions such as input and output functions, computing functions, and information memory functions.

In Fig. 1, the computer 30 performs control of the concentration of oxalic acid in the etching solution, the concentration of dissolved indium in the etching solution, the concentration of gallium, or the concentration of zinc. However, a control device capable of controlling the concentration of dissolved metal may be separately provided. A control device that controls the concentration of oxalic acid. From the viewpoint of more easily realizing the configuration of the device in a space-saving manner, it is preferable to maintain the management of the oxalic acid concentration and the dissolved metal concentration by the integrally formed control device, but it is more preferable to perform calculation functions of various calculations, Memory function for holding measurement data, etc., input of set value, measurement data, or calculation result The output functions such as display of various information can be completed by a computer built in the etching liquid management device in batch processing.

[Operation example] (etching liquid management method)

Next, the operation of the etching processing apparatus having the above configuration will be described. In the following, an oxalic acid aqueous solution is used as an etchant for etching a metal oxide film, an ITO film, an IZO film, a transparent conductive film such as an IGO film, or an oxide semiconductor film such as an IGZO film.

When the liquid feeding pump 8 is operated, the etching liquid stored in the etching processing tank 1 is supplied to the etching liquid atomizer 7 via the circulation line 10, and is ejected from the etching liquid atomizer 7. Thereby, the surface of the substrate 6 conveyed via the roller conveyor 5 is etched. The etchant is maintained at 35 ° C, for example, to maintain a specified etch rate.

The etching liquid after the etching is dropped into the etching treatment tank 1 and stored again, and is supplied to the etching liquid atomizer 7 via the circulation line 10 in the same manner as described above, and is ejected from the etching liquid atomizer 7 from this.

For example, if the etching liquid maintained at 35 ° C is sprayed, the water preferentially evaporates. Therefore, the oxalic acid concentration of the etching solution rises. Oxalic acid dissolves indium and becomes oxalic acid ions and indium ions, which are consumed. However, due to the large amount of evaporation of water, oxalic acid is concentrated and the etching rate is increased. Further, by repeating the etching, indium which is eluted from the surface of the substrate by etching is accumulated as a dissolved metal in the etching liquid. When the concentration of the dissolved metal in the etching solution rises, the elution of the metal component from the surface of the substrate is suppressed, so that the etching performance of the etching solution is lowered. As a result, by etching, the etching performance changes due to an increase in the acid concentration of the etching liquid and an increase in the dissolved metal concentration. Therefore, in order to prevent corrosion For the change of the engraving, the following control is performed.

First, in the measurement unit E, the conductivity value (conductivity measurement step) of the physical property value related to the oxalic acid concentration of the etching liquid is measured. The etching liquid used in the etching process is continuously sampled continuously by the sampling pipe 31 and the sampling pump 32, and supplied to the measuring unit E. The sampled etchant is used to detect the conductivity value of the etchant by the conductivity meter 17.

The conductivity meter 17 receives the command from the computer 30, repeatedly detects the conductivity value of the etching liquid at a predetermined interval, and returns the measurement data to the computer 30. In the computer 30, the correlation (for example, a linear relationship) between the oxalic acid concentration and the conductivity value of the etching liquid obtained in advance is held as a calibration curve, and based on the correlation, the oxalic acid of the etching liquid is calculated from the detected conductivity value. concentration.

In the computer 30, the oxalic acid concentration of the etching liquid which is constantly monitored in this manner is controlled by the replenishment replenishing liquid to be maintained at a predetermined management value (the oxalic acid concentration replenishing liquid transportation control step) in comparison with the management value.

The control system may employ various control methods such as proportional control, integral control, and differential control, but it is preferable to combine PID (Proportional Integral Derivative) control. As long as the appropriate PID parameters are set in the computer 30, the oxalic acid concentration can be appropriately maintained and managed at a designated management value.

When the oxalic acid concentration of the etching liquid is lowered, the flow rate adjusting valve 27 provided in the middle of the piping for supplying the oxalic acid raw liquid from the oxalic acid raw material supply tank 23 is opened in accordance with a control command calculated by the computer 30, and the necessary amount of the acid liquid is supplied. . When the oxalic acid concentration of the etching solution rises, The control command calculated by the computer 30, for example, opens the flow rate adjusting valve 28 provided in the middle of the existing pure water pipe for supplying pure water, and supplies a necessary amount of pure water. As a result, the oxalic acid concentration of the etching solution is constantly monitored, and when the management value is deviated, control can be performed to return to the management value, and the control is maintained at the designated management value.

When the oxalic acid concentration of the etching liquid is not lowered, the oxalic acid raw material supply tank 23 and the flow rate adjusting valve 27 are not required, and when the oxalic acid concentration does not rise, the piping for supplying pure water and the flow rate adjusting valve 28 are not required.

The density value (density measurement step) related to the dissolved metal concentration is measured while maintaining the oxalic acid concentration at a predetermined management value. Further, as described above, since the etching liquid is continuously sampled continuously to supply the replenishing liquid so as to have a predetermined management value, the oxalic acid concentration is constantly maintained at a predetermined management value. In the measurement of the density value by the densitometer 18, the etching liquid is continuously sampled continuously through the sampling pipe 31 and the sampling pump 32, and is supplied to the measuring unit E, and the density value of the etching liquid is detected by the densitometer 18.

The density meter 18 receives an instruction from the computer 30 to repeatedly detect the density value of the etching liquid at a predetermined interval, and returns the measurement data to the computer 30. In the computer 30, the correlation between the concentration of the oxalic acid previously obtained and the concentration of the indium concentration, the gallium concentration, or the zinc concentration of the etching solution maintained at the management value (for example, a linear relationship) is maintained as a calibration curve. Based on the correlation, at least one of the indium concentration, the gallium concentration, or the zinc concentration of the etching solution is calculated based on the detected density value.

In the computer 30, the concentration of dissolved indium in the etching solution so frequently monitored, the concentration of gallium or the concentration of zinc are managed by them. The value comparison is performed so as to control the replenishment replenishment (the replenishment liquid supply control step for metal concentration) so as to be equal to or less than the threshold value of the managed concentration.

When the dissolved metal concentration of the etching liquid rises, the flow rate adjusting valve 26 for supplying the fresh liquid supply tank 22 for supplying the etching liquid is opened in accordance with a control command calculated by the computer 30, and a necessary amount of the etching liquid is supplied. As a result, the concentration of the dissolved metal in the etching solution is constantly monitored, and when the threshold value is exceeded, the control is set to be below the threshold to maintain the threshold below the managed concentration. Take control.

The oxalic acid concentration of the etching liquid in the etching treatment tank 1 and the concentration of the dissolved metal can be managed within a certain range by the control of the above computer 30. For example, even if the oxalic acid concentration in the etching or the concentration of the dissolved metal increases due to the etching treatment portion A, the oxalic acid concentration and the dissolved metal concentration of the etching liquid in the etching treatment tank 1 can be managed within a certain range.

[etched film]

As the film to be etched used in the present embodiment, a film containing at least one of indium, gallium or zinc can be used. For example, an ITO film, an IZO film, an IGO film or an IGZO film can be used.

[etching solution]

As the etching liquid used in the embodiment, an etching solution containing at least oxalic acid can be used.

[Second embodiment]

The etching liquid management device according to the second embodiment of the present invention is measured by the conductivity meter 17 of the etching liquid management device according to the first embodiment. The conductivity value and the density value measured by the densitometer 18 are calculated by a multivariate analysis method (for example, multiple regression analysis) to calculate the oxalic acid concentration of the etching solution, the concentration of dissolved indium in the etching solution, the concentration of gallium, or The calculation function (component concentration calculation means) of at least one concentration of zinc concentration. The etching processing mechanism including the etching liquid management device of the second embodiment can be the same as the etching processing mechanism of the first embodiment shown in Fig. 1.

The etching liquid containing a metal component or the like eluted from the film to be etched is usually composed of various components such as an acid component, a dissolved metal component, and an additive component such as a surfactant. Therefore, in the etching liquid management apparatus according to the first embodiment, even if the concentration of oxalic acid is maintained at a predetermined value, the concentration of the indium concentration, the gallium concentration, or the zinc concentration of the etching solution is equal to or higher than the density value. In the specified concentration range, the correlation of the linear relationship or the like can be obtained approximately. Generally, it is not the physical property value of the measured etching liquid that is only related to the concentration of the specific component. The conductivity value of the etching liquid associated with the oxalic acid concentration is strictly affected by other electrolyte components even if it is strongly dependent on the oxalic acid concentration. Further, the density value of the etching liquid relating to the concentration of the dissolved metal in the etching liquid is strictly influenced by the other components even if it is strongly dependent on the dissolved metal concentration. Therefore, from the viewpoint of more precisely managing the concentration of the component of the etching liquid, the physical property value of the measured etching liquid is regarded not only in relation to the concentration of the specific component detected by the etching liquid but also in relation to the concentration of other components. To deal with, it is necessary and must not be lacking. In this regard, by using a multivariate analytical method, such as multiple regression analysis, the measured physical properties of the etchant can be determined from a plurality of samples. To more accurately calculate the concentration of each component that affects this.

The etching liquid management apparatus of the present embodiment is mainly applied to the measurement, control, and management of the oxalic acid concentration and the dissolved metal concentration of the etching liquid in the etching process, and the oxalic acid concentration and the dissolved metal concentration in the etching liquid. Multivariate analysis methods (for example, multiple regression analysis) are used in the calculation method. In the first embodiment, the oxalic acid concentration of the etching solution is set to a controlled concentration range, and at least one of the concentration of dissolved indium in the etching solution, the concentration of gallium, or the concentration of zinc is measured. However, in the present embodiment, By multivariate analysis (for example, multiple regression analysis) to determine the concentration of the etching solution, the oxalic acid concentration and the indium concentration, the gallium concentration or the zinc concentration of the etching solution can be obtained from the conductivity value and the density value. At least one concentration (component concentration calculation step). Therefore, in the second embodiment, according to the oxalic acid concentration and at least one of the indium concentration, the gallium concentration, or the zinc concentration, the oxalic acid concentration is in the range of the controlled concentration, and the indium concentration and the gallium are The concentration or the zinc concentration is controlled to be the delivery of the replenishing liquid (the replenishing liquid delivery control step) in such a manner as to be below the threshold of the managed concentration. The control and other configurations of the replenishing liquid are omitted in the same manner as in the first embodiment.

[Multi-component operation method]

The inventors have learned from experiments that when indium is dissolved in an aqueous solution of oxalic acid, the measured values of the conductivity and density of the aqueous oxalic acid solution do not correspond to only one component of the oxalic acid concentration or the dissolved indium concentration, but each has Associated, the concentration can be more accurately determined by multiple regression analysis.

In addition, the inventors of the present invention conducted research and analysis on the correlation, and found that the linear value can be obtained from the two types of characteristic values (the conductivity value and the density value of the aqueous oxalic acid solution in which at least one of indium, gallium, and zinc are dissolved). Regression analysis method (MLR-ILS) (Multiple Linear Regression-Inverse Least Squares) to calculate the component concentration (oxalic acid concentration, and dissolution) of a more accurate etching solution (aqueous solution of oxalic acid in which at least one of indium, gallium, and zinc is dissolved) At least one concentration of indium, gallium, and zinc).

Here, the arithmetic expression of the multiple regression analysis is exemplified. Multiple regression analysis consists of two phases of correction and prediction. In the multiple regression analysis of the n component system, m calibration standard solutions were prepared. C _ij represents the concentration of the component of the jth number present in the solution of the i-th. Here, i=1~m, j=1~n. For m standard solutions, p characteristic values (for example, absorbance or conductivity or density at a certain wavelength) A _ik (k = 1 to p) were measured. The concentration data and the characteristic value data can each be collectively represented in the form of an array (C, A).

The array associated with these arrays is referred to as a correction array, and is represented here by the symbol S (S _kj ; k = 1 to p, j = 1 to n).

C=A. S

From the known C and A (the content of A is not only a homogeneous measured value but also a heterogeneous measured value may be mixed. For example, conductivity and density Degree), the S-system correction phase is calculated by the array operation. At this time, it is necessary to p>=n and m>=np. Since each element of S is an unknown number, it is preferably m>np, and the case is as follows.

S=(A ^T A) ^-1 (A ^T C)

Herein, the superscript T system means a transposed array, and the superscript -1 means the opposite array.

For the sample liquid with unknown concentration, p characteristic values are measured. If they are regarded as Au (Au _k ;k=1~p), multiply them by S to obtain the desired concentration Cu (Cu _j ;j =1~n).

Cu=Au. S

This is the forecasting phase.

The present inventors used a sample liquid in which an aqueous solution of oxalic acid in which indium has been dissolved as described in Table 1 above, and selected one of a plurality of calibration standard solutions as an unknown sample, and obtained a corrected array from the remaining standard solution to calculate a hypothetical unknown. The concentration of the sample was calculated by the method of the Leave-One-Out method (go to a cross-validation method) which is compared with the known concentration (weight modulation value), and the calculation result is shown in Table 2. Table 2 shows the concentrations of oxalic acid and indium determined from the measured values of conductivity and density.

The correction array at this time is shown in Table 3.

By using the operation of the multiple regression analysis based on the above experiment, the inventors have learned that if the conductivity of the etching solution is within a specified range (for example, 55.00 ± 2.5 (mS/cm)), the standard deviation can be 24 (ppm). The accuracy of the degree is calculated as the dissolved indium concentration, and the oxalic acid concentration is calculated with an accuracy of the standard deviation of 32 (ppm).

Further, in the present embodiment, the multi-component calculation method is realized by the arithmetic function of the computer 30. That is, if the calculation program of the multivariate analysis method (for example, multiple regression analysis method) is input in advance in the computer 30, since the computer 30 is connected to the conductivity meter 17 and the density meter 18, it is preferable. The conductivity value and the density value are obtained, and the oxalic acid concentration and the dissolved metal concentration of the etching solution are calculated by an arithmetic program.

Since the treatment of the oxalic acid concentration and the dissolved metal concentration of the etching liquid in the present embodiment is the same as that of the first embodiment, the description thereof will be omitted.

[Measurement method of component concentration]

This embodiment can be used as a component concentration measuring method for measuring the concentration of a component in an etching solution.

As a method of measuring the component concentration of the etching liquid, first, the conductivity value of the etching liquid (the conductivity measuring step) is measured by the conductivity meter 17. Further, the density value of the etching liquid (density measuring step) is measured by the densitometer 18. Based on the conductivity value measured by the conductivity meter 17 and the density value measured by the densitometer 18, the oxalic acid concentration of the etching solution and the concentration of dissolved indium in the etching solution are calculated, for example, by the multi-component calculation method described above. At least one of a concentration of gallium or a concentration of zinc (component concentration calculation step).

Since the component concentration in the etching liquid is calculated by the multi-component calculation method, the component concentration in the etching liquid can be accurately obtained.

1‧‧‧etching tank

2‧‧‧Overflow trough

3‧‧‧Level gauge

4‧‧‧ etching chamber cover

5‧‧‧Roller conveyor

6‧‧‧Substrate

7‧‧‧etching liquid sprayer

8‧‧‧ Liquid pump

9‧‧‧Filter

10,12‧‧‧Circulation pipeline

11‧‧‧Circulating pump

17‧‧‧Electrometer

18‧‧‧density meter

20‧‧‧Liquid discharge pump

21‧‧‧ Etching stock solution supply tank ((replenishment liquid) supply tank)

22‧‧‧ etching new liquid supply tank ((replenishment liquid) supply tank)

23‧‧‧oxalic acid stock solution supply tank ((replenishment liquid) supply tank)

24‧‧‧Pipe

25, 26, 27‧‧‧ flow control valve

28‧‧‧Flow regulating valve (pure water supply valve)

29‧‧‧Confluence pipeline

30‧‧‧ computer

31‧‧‧Sampling piping

32‧‧‧Sampling pump

33‧‧‧Reflow piping

100‧‧‧etching mechanism

A‧‧‧ etching processing department

B‧‧‧ Etching liquid circulation department

D‧‧‧Replenishment Supply Department

E‧‧‧Determination Department

Claims (5)

An etching liquid management device which is an etching liquid management device for managing an etching liquid, which is an etching solution containing oxalic acid and is used for etching an etched film containing at least one of indium, gallium or zinc, and is characterized by The method includes a conductivity meter for measuring a conductivity value of the etching solution, a density meter for measuring a density value of the etching solution, and a replenishing liquid delivery control device according to an oxalic acid concentration and a conductivity value of the etching solution. The correlation between the correlation and the measurement result of the conductivity meter is such that the concentration of the oxalic acid is within a concentration range which is related to the concentration of the indium concentration, the gallium concentration, or the zinc concentration of the etching solution. And a method according to the correlation between the concentration of the indium concentration, the gallium concentration or the zinc concentration of the etching solution and the density value and the measurement result of the density meter, and at least the indium concentration, the gallium concentration or the zinc concentration The delivery of the replenishing liquid supplied to the etching liquid is controlled in such a manner that one concentration becomes equal to or less than the threshold value of the managed concentration. An etching liquid management device which is an etching liquid management device for managing an etching liquid, which is an etching solution containing oxalic acid and is used for etching an etched film containing at least one of indium, gallium or zinc, and is characterized by A conductivity meter for measuring a conductivity value of the etching solution, a density meter for measuring a density value of the etching solution, and a component concentration calculation means for measuring a conductivity value measured by the conductivity meter and Calculating the oxalic acid concentration of the etching solution and the etching by multivariate analysis method through the density value measured by the densitometer At least one of an indium concentration, a gallium concentration, or a zinc concentration of the liquid; and a replenishing liquid transport control means, wherein the oxalic acid concentration of the etching liquid calculated by the component concentration calculating means is within a managed concentration range, and The supply of the replenishing liquid supplied to the etching liquid is controlled so that at least one of the indium concentration, the gallium concentration, and the zinc concentration of the etching liquid becomes equal to or less than a threshold value of the managed concentration. An etching liquid management method for managing an etching liquid for etching an etchant containing an etchant for oxalic acid and for etching an etched film containing at least one of indium, gallium or zinc, characterized in that And a conductivity measuring step of determining a conductivity value of the etching solution; and a oxalic acid concentration using a replenishing liquid conveying control step, wherein the correlation between the oxalic acid concentration and the conductivity value of the etching solution and the conductivity are determined according to the conductivity In the measurement result of the step, the oxalic acid concentration is adjusted to a concentration range in which the concentration of the indium concentration, the gallium concentration, or the zinc concentration of the etching solution is correlated with the density value, and the supply of the etching solution is supplemented. a liquid transporting step; a density measuring step of measuring a density value of the etching liquid in which the oxalic acid concentration is controlled within the concentration range by the supplemental liquid transport control step; and a metal concentration replenishing liquid transport controlling step, Correlation between the concentration of the indium concentration, the gallium concentration or the zinc concentration of the etching solution and the density value and the measurement of the density measuring step , Indium concentration of the etching solution, or the concentration of gallium in the zinc concentration to at least one The delivery of the replenishing liquid supplied to the etching solution is controlled in such a manner as to be below the threshold of the managed concentration. An etching liquid management method for managing an etching liquid for etching an etchant containing an etchant for oxalic acid and for etching an etched film containing at least one of indium, gallium or zinc, characterized in that The method includes a conductivity measurement step of measuring a conductivity value of the etching solution, a density measurement step of measuring a density value of the etching solution, and a component concentration calculation step of electrically conducting the conductivity according to the conductivity measurement step. a rate value and a density value measured by the density measuring step, and calculating at least one of an oxalic acid concentration of the etching solution and an indium concentration, a gallium concentration, or a zinc concentration of the etching solution by a multivariate analysis method; and a replenishing liquid delivery control a step of controlling the concentration of oxalic acid of the etching solution calculated by the component concentration calculation step to be within a controlled concentration range, and managing at least one of an indium concentration, a gallium concentration, or a zinc concentration of the etching solution The supply of the replenishing liquid supplied to the etching liquid is controlled in such a manner that the concentration is below the threshold value. A method for measuring a component concentration of an etching solution, comprising: a conductivity measuring step of measuring an electrical conductivity value of an etching solution containing an etchant of oxalic acid and containing at least at least one of indium, gallium or zinc Etching of the etched film; a density measuring step of measuring the density value of the etchant; and a component concentration calculating step based on the conductivity measured The conductivity value measured in the step and the density value measured by the density measurement step are used to calculate at least one of the oxalic acid concentration of the etching solution and the indium concentration, the gallium concentration, or the zinc concentration of the etching solution by a multivariate analysis method.