KR20160010258A - Etching solution managing apparatus, etching solution managing method and concentration measuring method for component of etching solution - Google Patents

Abstract

The present invention provides an etching solution management apparatus, an etching solution management method and a component concentration of an etching solution measurement method proximately and constantly maintaining and managing performance as an etching solution of an oxalic-based etching solution and restraining precipitation of solid particles. The present invention comprises: a conductivity meter (17) measuring a conductivity value of the etching solution and a densimeter (18) measuring a density value of the etching solution; and a supplement solution transfer liquid control means controlling a transfer liquid of a supplement solution supplied to the etching solution based on a correlation between oxalic acid concentration of the etching solution and the conductivity value and a measurement value of the conductivity meter (17) and based on the correlation between dissolved solution concentration of the etching solution and the density value and the measurement result of the densimeter (18).

Description

TECHNICAL FIELD [0001] The present invention relates to an etching solution processing apparatus, an etching solution management method, and a method for measuring a component concentration of an etching solution.

The present invention relates to an etchant management apparatus, an etchant management method, and a method of measuring the concentration of an etchant, and more particularly, to an etchant management apparatus, an etchant management method, and an etchant management method for adjusting the concentration of an etchant varying in concentration over time, And a method for measuring the concentration of a component.

In the etching process in the semiconductor or liquid crystal substrate fabrication process, an etchant having a liquid composition appropriately prepared according to an object to be etched is circulated or stored in an etching bath and repeatedly used. (Hereinafter referred to as an " ITO film "), an indium zinc oxide film (hereinafter referred to as an " IZO film "), or an indium gallium oxide film (Hereinafter referred to as " IGO film ") or an oxide semiconductor film such as an In-Ga-Zn-O system oxide semiconductor film containing indium, gallium and zinc An oxalic acid aqueous solution containing oxalic acid in an amount of about 3.4% or a solution obtained by adding an additive such as a surfactant thereto (hereinafter, an etchant containing oxalic acid as a main component thereof is referred to as an "oxalic acid etchant"). Are used.

When an ITO film, an IZO film, an IGO film, or an IGZO film is etched with such an oxalic acid-based etching solution, indium or zinc from the ITO film or indium or zinc from the ITO film or indium or zinc from the IZO film, Metal components such as indium or gallium or zinc are eluted from the IGZO film into the etching solution. Therefore, the metal components eluted from the etched film accumulate in the etching solution as the etching process progresses. However, since the metal components accumulated in the etching liquid tend to suppress leaching of the metal component from the etching film, if the etching liquid is not appropriately controlled, the etching rate decreases with the progress of the etching process, This deteriorates.

Among the metal components eluted from the ITO film, the IZO film, the IGO film, and the IGZO film in the oxalic acid-based etching solution, gallium or indium is particularly liable to precipitate as a solid with a low solubility in an oxalic acid-based etching solution. As a result, gallium or indium accumulated in the etchant by etching has precipitated as solid matter to generate etch residue, thereby causing deterioration of quality.

In addition, as the etching process progresses, the etching solution is consumed by the etching reaction and its main component is reduced by the etching reaction. In addition, since the etching chamber is sucked and exhausted so that the noxious gas does not leak to the outside, some components such as moisture and acid volatilize from the etching solution due to the exhaust gas. For this reason, the liquid composition of the etching solution fluctuated with time and was not stabilized, and the dissolved metal was increased and the etching performance was deteriorated.

In order to prevent deterioration of quality due to precipitation of solid matter, for example, the following Patent Document 1 discloses a method in which an etching liquid is filtered with an NF membrane (Nanofiltration Membrane membrane) to remove solid particles precipitated in the etching liquid and regenerated Device is described.

[Patent Document 1] JP-A-2006-013158

However, the method and apparatus disclosed in Patent Document 1 are for recovering metal from the etchant after use, and the metal concentration of the etchant in use has not been studied. In addition, although the solid particles to be deposited can be removed by providing the NF film, the etching performance of the etching solution is not improved because the metal concentration in the etching solution is high.

An object of the present invention is to provide an etchant management apparatus, an etchant management method and an etchant management method, which are capable of substantially maintaining and managing the performance of an oxalic acid etchant as an etchant and suppressing precipitation of solid particles, And a method thereof.

In order to achieve the above object, the present invention provides an etchant management apparatus for managing an etchant used for etching an etched film containing oxalic acid, the etchant including at least one of indium, gallium, and zinc, A concentration meter for measuring the density value of the etchant, and a concentration meter for measuring the oxalic acid concentration based on the correlation between the oxalic acid concentration and the conductivity value of the etchant and the measurement result of the conductivity meter, the indium concentration, the gallium concentration or the zinc concentration The concentration of the etching solution is controlled so that the concentration of the etching solution is within a concentration range in which there is a correlation between one concentration and the density value and the correlation between the density value and the concentration of either the indium concentration, Based on the results, at least one of the indium concentration, gallium concentration or zinc concentration is below the threshold of the administered concentration To provide an etching solution administration device, it characterized in that it includes a replenisher liquid feed control means for controlling the liquid feeding of the replenishing solution (送 液) is loaded in the etching solution.

According to the present invention, since the oxalic acid concentration of the etchant has a correlation with the conductivity in the oxalic acid concentration region including the control range of the oxalic acid concentration of the etchant, if the correlation between the oxalic acid concentration and the etch rate of the etchant is obtained in advance, It is necessary to control the concentration of oxalic acid in the etchant based on the conductivity value of the etchant measured by the rate meter to a concentration range in which there is a correlation between the concentration value and either the indium concentration, the gallium concentration or the zinc concentration of the etchant. The liquid amount of the replenishing liquid can be calculated. Thus, by replenishing the calculated replenishing liquid to the etchant, the concentration of oxalic acid in the etchant is controlled within a concentration range in which there is a correlation between one of the indium concentration, the gallium concentration, or the zinc concentration and the density value of the etchant, The concentration can be controlled to a substantially constant value. When indium is eluted from the etched film into the etching solution, the indium concentration and density of the etching solution in the indium concentration region including the control range of the indium concentration of the etching solution in which the oxalic acid concentration is controlled within the predetermined concentration range The relationship between the indium concentration of the etchant and the density can be obtained in advance so that the indium concentration of the etchant is determined based on the density value of the etchant measured by the density meter, Value "), the liquid amount of the replenishing liquid necessary for controlling the concentration can be calculated. Therefore, the indium concentration of the etchant can be made to be equal to or lower than the threshold value by replenishing the calculated replenisher of the liquid amount into the etchant. Therefore, the concentration of indium dissolved in the etching solution can be controlled without saturating, so that the solid particles derived from indium can be prevented from precipitating in the etching solution. Furthermore, since the oxalic acid concentration of the etching liquid can be controlled to be substantially constant and the indium solubility of the etching liquid can be maintained, the etching performance of the etching liquid can be maintained in a good state. When gallium or zinc is eluted not only from indium but also gallium or zinc from the etched film through etching of the IGZO film, a correlation is previously obtained between the indium concentration, the gallium concentration and the zinc concentration and the density in the same manner, It is possible to replenish the replenishing liquid of the required liquid amount based on the density value of the etchant measured by the system and to set the gallium concentration and the zinc concentration of the etchant to be equal to or less than the threshold value in addition to the indium concentration of the etchant, It is possible to prevent precipitation of particles and to maintain the etching performance of the etching solution in a good state.

In order to achieve the above object, the present invention provides an etchant management apparatus for managing an etchant used for etching an etched film containing oxalic acid, the etchant including at least one of indium, gallium, and zinc, The concentration of oxalic acid in the etchant and the concentration of indium in the etchant were measured by a multivariate analysis method based on the conductivity meter which measures the density of the etchant, the density meter which measures the density of the etchant, the conductivity value measured by the conductivity meter, , A concentration of gallium or a concentration of zinc, a concentration concentration calculation means for calculating a concentration of oxalic acid in the etching solution calculated by the concentration calculation means, A replenishment liquid replenished to the etchant so that the concentration of at least one of the concentrations is less than or equal to a threshold value of the controlled concentration Provides an etching solution administration device, it characterized in that it includes a replenisher liquid feed control means for controlling the liquid feeding (送 液).

According to the present invention, at least one of the concentration of oxalic acid in the etching solution, the indium concentration in the etching solution, the gallium concentration or the zinc concentration can be calculated with high accuracy by the multivariate analysis method from the conductivity value and the density value of the etching solution. And the concentration of oxalic acid in the etching solution is controlled to be within the controlled concentration range based on at least one of the concentration of oxalic acid in the etching solution, the concentration of indium in the etching solution, the concentration of gallium or the concentration of zinc, A replenishing liquid of a required liquid amount can be supplied to the etching liquid so that the concentration of at least one of the liquids is equal to or less than the threshold value. Therefore, it is possible to manage the concentration of oxalic acid in the etching liquid to a substantially constant value, and to manage the etching liquid with an indium concentration, a gallium concentration, or a zinc concentration in which solid particles derived from indium, gallium-derived or zinc do not precipitate in the etching solution The etching performance of the etching solution can be maintained in a good state.

The present invention provides an etchant management method for managing an etchant used for etching an etched film containing oxalic acid, the etchant including at least one of indium, gallium, and zinc, Based on the correlation between the oxalic acid concentration and the conductivity value of the etchant and the measurement result of the conductivity measurement process, the oxalic acid concentration is a concentration and a density value of either the indium concentration, the gallium concentration or the zinc concentration of the etchant (Liquid feed) of the replenishing liquid replenished to the etching liquid so that the concentration of oxalic acid is controlled within the concentration range by the replenishment liquid feeding control step for oxalic acid concentration A density measurement step of measuring a density value of the etchant, an indium concentration of the etchant, Or zinc concentration and the density measurement value of at least one of the indium concentration, the gallium concentration or the zinc concentration on the basis of the correlation between the concentration and the density value and the measurement result of the density measurement process, And a replenishment liquid replenishment control for a metal concentration for controlling the replenishment of the replenishment liquid replenished to the etchant.

According to the present invention, since the oxalic acid concentration of the etchant has a correlation with the conductivity in the oxalic acid concentration region including the control range of the oxalic acid concentration of the etchant, if the correlation between the oxalic acid concentration and the conductivity is obtained in advance , The concentration of oxalic acid in the etchant measured based on the conductivity value of the etchant measured by the conductivity measuring step is adjusted such that the concentration of the indium, gallium, or zinc in the etchant has a correlation It is possible to calculate the liquid amount of the replenishing liquid necessary for control within the range. Therefore, by replenishing the calculated replenishing liquid to the etchant, the concentration of oxalic acid in the etchant is controlled within a concentration range in which there is a correlation between one of the indium concentration, the gallium concentration, or the zinc concentration in the etchant and the density value The concentration of oxalic acid can be controlled to a substantially constant value. Further, in the case where indium is eluted from the etched film into the etching solution, in the indium concentration region including the control range of the indium concentration of the etching solution in which the oxalic acid concentration is controlled within the predetermined concentration range, the indium concentration and density of the etching solution It is necessary to obtain a correlation between the indium concentration and the density of the etchant in advance so as to control the indium concentration of the etchant below the threshold value based on the density value of the etchant measured by the density measurement step The liquid amount of the replenishing liquid can be calculated. Therefore, the indium concentration of the etchant can be made to be equal to or lower than the threshold value by replenishing the calculated replenisher of the liquid amount into the etchant. Therefore, since the concentration of indium dissolved in the etching solution can be controlled without being saturated, the solid particles derived from indium can be prevented from precipitating in the etching solution. In addition, since the oxalic acid concentration of the etching solution can be controlled to be substantially constant and the indium solubility of the etching solution can be maintained, the etching performance of the etching solution can be maintained in a good state. When gallium or zinc is eluted not only from indium but also from gallium or zinc from the etched film by etching of the IGZO film, a correlation between the gallium concentration of the etchant and the zinc concentration and the density is obtained in advance, It is possible to prevent the precipitation of the gallium-derived or zinc-derived solid particles from occurring and to prevent the precipitation of the etchant from the etchant, The etching performance can be maintained in a good state.

The present invention provides an etchant management method for managing an etchant used for etching an etched film containing oxalic acid, the etchant including at least one of indium, gallium, and zinc, A density measurement step of measuring the density value of the etchant, a density measurement step of measuring the oxalic acid concentration of the etchant by the multivariate analysis method based on the conductivity value measured by the conductivity measurement step and the density value measured by the density measurement step, A concentration concentration calculation step of calculating a concentration of at least one of an indium concentration, a gallium concentration and a zinc concentration of the etching solution; a concentration concentration calculation step of calculating a concentration concentration of oxalic acid in the etching solution, Even if the concentration of at least one of the gallium concentration or the zinc concentration is less than or equal to the threshold value of the managed concentration And a replenishment liquid sending-out control step of controlling the sending-out (feeding) of the replenishing liquid replenished to the lock etchant.

According to the present invention, the oxalic acid concentration of the etchant, the indium concentration of the etchant, the gallium concentration or the zinc concentration, at least one of the concentration and the concentration of zinc is determined from the conductivity value and the density value of the etchant measured by the conductivity measuring step and the density measuring step Can be calculated with high accuracy. And the concentration of oxalic acid in the etching solution is controlled to be within the controlled concentration range based on at least one of the concentration of oxalic acid in the etching solution, the concentration of indium in the etching solution, the concentration of gallium or the concentration of zinc. A replenishing liquid having a necessary liquid amount can be supplied so that at least one concentration is equal to or less than the threshold value. Therefore, it is possible to manage the concentration of oxalic acid in the etching liquid to a substantially constant value and to manage the etching liquid with the indium concentration, gallium concentration or zinc concentration in which solid particles derived from indium, gallium-derived or zinc do not deposit in the etching solution, It is possible to maintain the etching performance in a good state.

In order to achieve the above object, the present invention provides an etching solution containing oxalic acid, which comprises a conductivity measuring step of measuring an electric conductivity value of an etching liquid used for etching an etching film containing at least one of indium, gallium or zinc, The concentration of oxalic acid in the etching solution, the concentration of indium in the etching solution, the concentration of gallium or the concentration of zinc in the etchant based on the conductivity value measured by the conductivity measuring step and the density value measured by the density measuring step by the multivariate analysis method And a concentration calculating step of calculating a concentration of at least one of the concentration of the etching solution and the concentration of the etching solution.

According to the present invention, at least one concentration of the oxalic acid concentration of the etchant, the indium concentration of the etchant, the gallium concentration or the zinc concentration is determined by the multivariate analysis method from the conductivity value and the density value of the etchant measured by the conductivity measuring step and the density measuring step It is possible to measure at least one of the oxalic acid concentration of the etching solution, the indium concentration of the etching solution, the gallium concentration, or the zinc concentration with high accuracy.

According to the etching liquid management device, the etching liquid management method, and the method of measuring the component concentration of the etching liquid of the present invention, it is possible to supply an appropriate amount of the replenishing liquid to the etching liquid based on the measured concentration values or physical property values. The concentration can always be controlled to a substantially constant value within the concentration range to be managed. In addition, the concentration of metal components such as indium, gallium, and zinc dissolved in the etching solution can be controlled to be not more than the threshold value of the always-managed concentration. Therefore, deterioration of the etching performance of the etching liquid can be prevented, liquid performance of the etching liquid is stabilized, and the life of the liquid is prolonged. In addition, precipitation of solid particles derived from metal components can be suppressed, and solid particles adhered to the etched film can be prevented from deteriorating in quality.

In addition, since the etchant is automatically maintained at the optimum liquid performance at all times, the downtime of the production apparatus can be reduced and the productivity can be improved. In addition, it is possible to prevent the generation of etching residue due to the precipitation of the molten metal as the etching process progresses, and to improve the product yield ratio.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a systematic view of an etching processing apparatus including an etching liquid management apparatus according to a first embodiment of the present invention,
2 is a graph showing the relationship between the concentration of oxalic acid in the etchant and the conductivity,
3 is a graph showing the relationship between the density of the dissolved metal and the density of the etching solution.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. However, the shapes, relative positions, and the like of the constituent devices described in this embodiment are not limited to the scope of the present invention, and are merely illustrative examples, unless otherwise specified.

[First Embodiment]

1 is a statistical view of an etching processing apparatus 100 including an etchant management apparatus according to a first embodiment of the present invention.

The etching solution management apparatus of the present embodiment is an etching solution for etching a metal film or a metal compound film which is an etching film mainly containing at least one of indium, gallium or zinc, wherein the etching solution is an aqueous solution containing oxalic acid, And when management of the dissolved metal concentration is important. 1 schematically shows an etching treatment section A including an etching treatment tank 1 which is connected to the etching solution management apparatus of the present invention and is maintained at a predetermined concentration of components and in which an etching solution is stored, A replenishing liquid supply section 21 to 23 for storing various replenishment liquids, and a replenishment liquid supply section 21 to 23, which is provided in the replenishment liquid supply line and is controlled to open and close by flow control valves 25 to 28, for circulating and stirring the etchant, A measurement section E for measuring the conductivity or density of the etchant correlated to the concentration of oxalic acid in the etchant and the concentration of the dissolved metal, and a computer 30 for performing various calculations and controls. The etchant management apparatus of the present invention is constituted by the measurement section E, the computer 30 and the flow control valves 25, 26, 27 and 28 in the replenishment liquid supply section D.

≪ Etching Process Part (A) >

The etching treatment section A is for spraying an etching solution onto the surface of the substrate to be transferred, thereby etching the surface of the substrate.

As shown in Fig. 1, the etching treatment section A includes an etching treatment tank 1 in which an etching solution is stored, an overflow tank 2 for receiving an etching solution in which overflow occurs from the etching treatment tank 1, A roller leveler 3 for measuring the level of the etching liquid in the etching treatment tank 1, an etching sephold 4 and a roller conveyor 5 for conveying the substrate 6 disposed above the etching treatment tank 1 conveyer, an etchant spray 7, and the like.

The etching treatment tank 1 and the etchant spray 7 are connected to each other by a circulation line 10 provided with a liquid feed pump 8 and a filter 9 for removing fine particles and the like of the etching liquid.

The etching liquid stored in the etching tank 1 is supplied to the etchant spray 7 through the circulation line 10 and sprayed from the etchant spray 7. Whereby the surface of the substrate 6 conveyed by the roller conveyer 5 is etched. On the other hand, the surface of the substrate 6 is covered with a metal film or a metal compound film and a registration film.

The etchant after the etching falls into the etching treatment tank 1, is stored again, is supplied to the etchant spray 7 through the circulation duct 10 as described above, and is sprayed from the etchant spray 7.

≪ Etching solution circulating part (B) >

The etching liquid circulating section B is mainly for circulating and stirring the etching liquid stored in the etching treatment tank 1.

The bottom of the etching treatment tank 1 is connected to the side of the etching treatment tank 1 by a circulation line 12 provided with a circulation pump 11 in the middle. The circulating pump 11 is operated to circulate the etchant stored in the etching tank 1 through the circulation line 12. The etching liquid is returned from the side of the etching treatment tank 1 through the circulation line 12 to the etching treatment tank 1 to stir the etchant stored therein.

When the replenishment liquid flows into the circulation duct 12 through the confluent channel 29, the introduced replenishment liquid is supplied into the etching treatment tank 1 while being mixed with the circulating etching liquid in the circulation duct 12.

≪ Replenisher supply part (D) >

The replenishing liquid supply unit (D) is for supplying the replenishing liquid into the etching treatment tank (1). Examples of the replenisher include an etching solution, an etching solution (fresh solution), a solution of oxalic acid, a pure water, and an etching regenerating solution. These are not necessarily all required, and the optimum replenishing liquid and the supplying device are selected depending on the composition of the etching liquid, the degree of concentration change, the equipment conditions, the operating conditions, the availability of the replenishing liquid, and the like.

The replenishing liquid supply unit D is provided with an etchant stock solution feeder 21, an etching fresh solution feeder 22, an oxalic acid stock solution feeder 23 and a pure water feeder And piping. However, the supply cylinders 21 to 23 are merely shown as an example, and the number of the supply cylinder and the kind of the replenishing liquid as the contents of the supply cylinder may be appropriately selected depending on the above-mentioned conditions.

Flow rate control valves 25 to 28, which are opened and closed by a computer 30, are installed in the piping pipes for supplying the replenishing liquid from the feed cylinders 21 to 23 and the pure water supplying unit, Are collected in the confluent conduit (29) before they are connected to the circulating conduit (12). On the other hand, in the present embodiment, the computer 30 and the flow rate control valves 25 to 28 correspond to the replenishing liquid supply control means. In each of the feed cylinders 21 to 23, N ₂ And the gas supply pipes 24 are connected to the supply pipes 21 to 23. The supply pipes 21 to 23 are pressurized by the N ₂ gas supplied from the pipe 24. Therefore, when at least one of the flow control valves 25 to 28 is controlled to be opened by the computer 30, the replenishment liquid corresponding to the controlled flow control valve is supplied to the liquid feed conduit (liquid feed conduit) And the circulation duct 12, as shown in Fig. On the other hand, a controller such as a sequencer may be used in place of the computer 30 to control opening and closing of the flow rate control valves 25 to 28. [

For example, when the flow rate control valve 25 (etchant replenishment valve) is controlled to be opened by the computer 30, the etchant stock solution stored in the etchant stock solution feeder 21 flows into the feed pipe (feed pipe) And is sent to the etching treatment tank 1 through the duct 29 and the circulation duct 12. Pure water is supplied from the pre-installed pipe to the liquid feed conduit (conduit conduit) 29 and the confluent conduit 29 from the pre-installed conduit, if the flow control valve 28 (pure water) And the circulation duct 12 to the etching treatment tank 1.

Since each flow control valve is controlled to flow a predetermined amount of liquid when it is opened, the required amount of supplemental liquid is supplemented by controlling the time at which the computer 30 opens each flow control valve.

In Fig. 1, each of the replenishing liquids flows into the circulation line 12 through each of the liquid feed pipes and the confluent pipeline 29, and is supplied into the etching treatment tank 1 while being mixed with the circulating circulating liquid in the circulation duct 12. It is also possible to supply the replenishing liquid by directly connecting each of the transfer pipes to the circulation pipe 12 or the etching treatment tank 1 without passing through the merging pipe 29. [

On the other hand, a liquid discharge pump 20 for discharging the etchant stored in the etching treatment tank 1 is provided. This is used in the initial cleaning or liquid exchange in the etching treatment tank 1.

In the replenishing liquid supply section (D), the replenishing liquid is replenished based on the oxalic acid concentration of the etchant obtained from the conductivity value measured by the conductivity meter (17) of the measuring section (E) described below. The replenishing liquid is replenished on the basis of the indium concentration, the gallium concentration or the zinc concentration of the etchant obtained from the density value measured by the density meter 18. With respect to the concentration of oxalic acid, the computer 30 compares the value of the oxalic acid concentration of the obtained etching liquid with the value of the controlled oxalic acid. When the oxalic acid concentration is insufficient, the oxalic acid concentration is increased. When the oxalic acid concentration is excessive, At least one of the etchant solution, etchant solution, etchant regeneration solution, oxalic acid stock solution, and water is replenished as a replenishing solution to control the concentration of oxalic acid to a substantially constant value within a controlled concentration range. The indium concentration, the gallium concentration, or the zinc concentration of the etchant is compared with the indium concentration, the gallium concentration, or the zinc concentration obtained, and the indium concentration, the gallium concentration, or the zinc concentration, At least one of an etchant solution, an etching solution, an etching regenerant solution, an oxalic acid solution, and water is replenished as a replenishing solution so as to lower the indium concentration, the gallium concentration, or the zinc concentration when the gallium concentration or the zinc concentration is equal to or higher than the threshold value, The indium concentration, the gallium concentration or the zinc concentration is controlled to be equal to or lower than the threshold value of the managed concentration. On the other hand, in the present invention, the "replenisher" is a solution that can be used to adjust the components of the etchant. It is a generic term for the etchant solution, etchant solution, etchant regeneration solution, oxalic acid stock solution and water. The replenishing liquid may be mixed before replenishing a plurality of liquids, or may be replenished separately.

The control of the component concentration of the etching solution is not limited to the control by comparing the concentration of oxalic acid, the concentration of indium, the concentration of gallium or the concentration of zinc with the control value, Or an integral value or a derivative value of the change over time of the concentration of oxalic acid obtained based on the value may be used. Or a control in which these are appropriately combined. It is possible to control the concentration of oxalic acid in the etchant to fall within a predetermined range based on the oxalic acid concentration of the etchant by interlocking the control device capable of realizing such control with the conductivity meter 17 and the flow rate control valves 25 to 28. [ Similarly, with respect to the metal concentration, it is also possible to use an integrated value or differential value over time of the indium concentration, gallium concentration, or zinc concentration that can be obtained based on the density value of the etching liquid, which is always monitored by the density meter 18. Alternatively, these may be appropriately combined. A control device capable of realizing the above-described control is interlocked with the density meter 18 and the flow rate control valves 25 to 28 so that the metal concentration of the etching liquid is controlled to be equal to or less than a managed threshold value based on the indium concentration, As shown in FIG.

In the above description, the replenishing liquid is adjusted based on the oxalic acid concentration of the etchant, the indium concentration of the etchant, the gallium concentration, or the zinc concentration. However, the replenishing liquid is measured by the conductivity meter 17 and the density meter 18 By setting the conductivity value and the density value within the range of the conductivity value corresponding to the concentration range in which the oxalic acid concentration is managed and the density value corresponding to the threshold value at which at least one of the indium concentration, Oxalic acid concentration, and indium concentration, gallium concentration, or zinc concentration.

≪ Measurement section (E) >

The measuring portion E measures at least one of the concentration of oxalic acid in the sampled etching solution, the concentration of indium dissolved in the etching solution, the concentration of gallium or the concentration of zinc.

The measuring section E includes a conductivity meter 17 for measuring the conductivity value of the sampled etchant which is connected to the sampling pump 32 for sampling the etchant from the circulation duct 10 and the sampling pipe 31, A density meter 18 for measuring the density value of the etching solution, and a return pipe 33 for returning the sampled etching solution. On the other hand, the sampling pipe 31 and the return pipe 33 may be connected directly to the etching treatment tank 1.

Since the concentration of oxalic acid in the etchant is correlated with the conductivity value in the oxalic acid concentration region including the managed concentration range, a correlation between the oxalic acid concentration and the conductivity value of the etchant is obtained in advance and the correlation is used. The oxalic acid concentration can be obtained more than the conductivity value measured by the method of the present invention. Since the concentration of dissolved metal in the etching solution is correlated with the density value in the dissolved metal concentration region including the control range of the dissolved metal concentration of the etchant in which the oxalic acid concentration is controlled within the predetermined concentration range, The correlation between any one of the concentration of gallium or the concentration of zinc and the density value is obtained. Using this correlation, the density value measured by the density meter 18 is higher than the indium concentration, the gallium concentration or the zinc concentration At least one of the concentrations can be obtained.

On the other hand, when a plurality of metals dissolve in the etching solution, for example, when the ITO film is etched, indium and tin are eluted and when the IZO film is etched, indium and zinc are eluted. When the IGO film is etched, indium and gallium are eluted , And when the IGZO film is etched, indium, gallium and zinc are eluted. In this case, the density value of the etchant depends on the concentration of indium, which is mainly used in atomic mass among these metal components. As for the dissolution ratio of other metal components in the etching solution, the indium oxide: tin oxide is about 90 to 95: 10 to 5% by mass in the case of the ITO film, and about 90 to 95: 10 to 5% by mass in the case of the ITO film. In the case of the IGZO film, Gallium: zinc = 1: 1: 1 mol. Therefore, the concentration of indium dissolved in the etching solution can be obtained by measuring the density value when a plurality of metals are dissolved in the etching solution, and the concentration of indium dissolved in the etching solution can be obtained by the composition of the film 0 for other metals.

The conductivity meter 17 and the density meter 18 are connected to the computer 30 so that measurement results and the like are communicated.

The correlation between the oxalic acid concentration of the etchant and the conductivity value measured by the conductivity meter 17 may well be a simple function of a polynomial, an exponential function, an algebraic function, , And more preferably a linear relationship.

Normally, the conductivity value of the etching solution is continuously and smoothly changed in accordance with the variation of the concentration of oxalic acid. Therefore, as the concentration of oxalic acid in the etching solution shows a gentle change with time, the conductivity value also shows a continuous gradual change over time. Therefore, the above-described correlation can be obtained between the conductivity value of the etching solution and the oxalic acid concentration in the oxalic acid concentration range including the management range of the oxalic acid concentration of the etching liquid. By using this correlation, the oxalic acid concentration of the etching liquid can be obtained from the conductivity value of the etching liquid measured by the conductivity meter 17.

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 density meter 18 may be uniquely correlated with each other, Is a relation that can be approximated by a simple function such as a polynomial, an exponential function, and an algebraic function, more preferably a linear relation.

Normally, the density value of the etchant changes continuously and smoothly with the change of the concentration of the dissolved metal. Therefore, as the concentration of the dissolved metal in the etchant shows a gradual change over time, the density value also shows a gradual gradual change over time. Therefore, in the concentration range including the concentration of indium dissolved in the etching solution, the concentration of dissolved gallium, or the concentration range of zinc concentration, it is preferable that the density of the etching solution and the concentration of either the indium concentration, the gallium concentration or the zinc concentration The same correlation as the above can be obtained. Using this correlation, at least one of the concentration of indium dissolved in the etching liquid, the concentration of gallium or the concentration of zinc can be obtained from the density value of the etching liquid measured by the density meter 18.

The supply amount of the replenishing liquid is controlled by the replenishment liquid supply control means so that the molten metal concentration value is equal to or less than the threshold value of the managed concentration by comparing the molten metal concentration value thus obtained with the management value.

It is preferable that the value at which the molten metal concentration is controlled is a molten metal concentration value at or below the upper limit of the concentration range in which the molten metal concentration is controlled. It is preferable to set the value at which the dissolved metal concentration is controlled in advance, but it may be appropriately adjusted during operation of the apparatus.

[Method for measuring oxalic acid concentration and dissolved metal concentration]

Next, one example of a method of measuring the oxalic acid concentration and the dissolved metal concentration of the etching solution will be described. In the following description, oxalic acid is used as the acid, the oxalic acid concentration of the etchant is 3.4%, and the dissolved metal in the etchant is indium. However, the present invention is not limited to this, It can also be a value.

As the etching solution, a 3.4% oxalic acid aqueous solution used for etching an ITO film, a transparent conductive film such as an IZO film or an IGO film, or an oxide semiconductor film such as an IGZO film, which is a kind of metal oxide film, Solution. The electric conductivity and the density of the simulated sample liquid were measured, and the correlation between the oxalic acid concentration and the indium concentration was examined.

A sample was prepared by measuring a predetermined amount of oxalic acid dihydrate and indium oxide and dissolving the sample in pure water to prepare samples of various concentrations. Table 1 shows the relationship between the prepared oxalic acid concentration (wt%), indium concentration (ppm), conductivity (mS / cm) and density (g / cm ³ ). 10 samples of A series (A-1 to A-10), 10 samples of B series (B-1 to B-10) and 14 samples of C series (C-1 to C-14) The conductivity and the density were measured for each. The C series sample is a sample simulating a situation in which the concentration of oxalic acid is controlled to be around 3.4%. On the other hand, the oxalic acid concentration and the indium concentration of the sample are values calculated from the measurement values of the reagents measured for the sample preparation. The concentration of oxalic acid is the concentration converted into anhydrate. The temperature at the time of measurement was the entire sample measurement temperature of 25 占 폚.

Sample
No.              Weight adjustment value                 Measurement result  Concentration of oxalic acid (wt%)     Indium concentration (ppm)    Conductivity (mS / cm)      Density (g /)  A-1              3.4                   0           54.90050            1.013258  A-2              3.7                 100           58.09550            1.014863  A-3              3.1                 100           51.74878            1.012157  A-4              3.3                 200           53.87667            1.013259  A-5              3.5                 200           56.05467            1.014004  A-6              3.9                 300           59.97350            1.015858  A-7              2.9                 300           49.27683            1.011436  A-8              3.6                 400           56.70939            1.014291  A-9              3.9                 400           59.72589            1.015759  A-10              3.2                 500           52.32689            1.012460  B-1              3.5                   0           55.92256            1.013966  B-2              3.0                 100           50.59261            1.011763  B-3              3.6                 150           57.02933            1.014672  B-4              4.0                 150           60.90344            1.016514  B-5              3.2                 175           52.78144            1.012851  B-6              4.5                 175           65.74339            1.018869  B-7              2.1                 200           39.71483            1.007763  B-8              4.5                 250           65.75661            1.018988  B-9              2.9                 250           49.45389            1.011475  B-10              3.8                 275           59.07256            1.015918  C-1           3.3853                   0           54.71689            1.013515  C-2           3.4191                  25           55.07344            1.013743  C-3           3.3992                  40           54.86711            1.013657  C-4           3.3764                  55           54.65772            1.013637  C-5           3.4318                  70           55.23944            1.013847  C-6           3.3400                  80           54.26733            1.013472  C-7           3.3587                 105           54.45883            1.013604  C-8           3.4583                  85           55.49522            1.014024  C-9           3.4500                 185           55.44239            1.014149  C-10           3.4388                 225           55.34056            1.014151  C-11           3.3561                 235           54.47461            1.013749  C-12           3.3876                 140           54.84544            1.013849  C-13           3.4100                 170           55.08317            1.013948  C-14           3.3867                 220           54.83614            1.013866

Figures 2 and 3 are graphs of the results of Table 1. 2 is a graph plotting measurement results of conductivity values of all samples in a coordinate system in which the axis of abscissas is the oxalic acid concentration (wt%) of the sample and the axis of ordinate is the conductivity (mS / cm) of the sample. As is apparent from Fig. 2, it can be confirmed that the concentration of oxalic acid and the conductivity of the aqueous oxalic acid solution in which indium is dissolved are in a linear relationship. Therefore, it can be confirmed that the oxalic acid concentration of the oxalic acid aqueous solution can be obtained by detecting the conductivity of the oxalic acid aqueous solution in the oxalic acid concentration region where this linear relationship is obtained based on this relationship.

3 is a graph plotting density measurement results of all samples in a coordinate system in which the abscissa indicates the indium concentration (ppm) of the sample and the ordinate indicates the density (g / cm ³ ) of the sample. As is clear from Fig. 3, it can be confirmed that the indium concentration and the density are in a linear relationship in the C series sample imitating the case where the concentration of oxalic acid is controlled at a substantially constant value. Therefore, when the concentration of oxalic acid is almost constant based on this relationship, it can be confirmed that the concentration of indium dissolved in the aqueous oxalic acid solution can be obtained by detecting the density of the aqueous oxalic acid solution.

As described above, the inventors of the present invention have found by experiment that there is a linear relationship between the concentration of oxalic acid in the etching liquid and the conductivity of the etching liquid, and based on this linear relationship, it is possible to measure the acid concentration of the etching liquid by detecting the conductivity of the etching liquid I will.

When the concentration of oxalic acid is controlled to be substantially constant by experiments, the present inventors found that there is a linear relationship between the dissolved metal concentration of the etching solution and the density of the etching solution, and based on this linear relationship, the density of the etching solution The dissolved metal concentration of the etching solution can be measured.

The management range of the 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 changing the concentration of oxalic acid to a substantially constant value, it is possible to suppress the change in the density value due to the influence of the change in the concentration of oxalic acid, so that the change in the concentration of indium can be correlated to the change in density of the etching solution. Therefore, the concentration of indium dissolved in the solution can be accurately measured.

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

1, the conductivity meter 17 and the density meter 18 are provided separately from the etching treatment tank 1, and the etching solution is sampled through the sampling pipe 31. However, the conductivity meter 17 and the density By providing the measurement section of the system 18 in the etching treatment tank 1, the acid concentration and the dissolved metal concentration of the etching solution can be obtained.

≪ Computer 30 >

The computer 30 is electrically connected to the conductivity meter 17, the density meter 18, the flow rate control valves 25 to 28, and the like. The computer 30 not only emits an operation command to these connected devices and controls them but also acquires measurement data of concentration of indium dissolved in the etching solution, gallium concentration or zinc concentration data, such as oxalic acid concentration, . In addition, there are various functions such as an input / output function, an arithmetic function, and an information storage function.

1, the computer 30 controls the concentration of oxalic acid in the etching solution, the concentration of indium dissolved in the etching solution, the concentration of gallium, or the concentration of zinc. However, the control device for controlling the dissolved metal concentration and the control device for controlling the concentration of oxalic acid May be separately installed. It is preferable to maintain the oxalic acid concentration and the dissolved metal concentration by a single control device from the viewpoint of simplifying the arrangement of the apparatus with a simpler space saving. More preferably, It is preferable that the present invention be performed by a computer incorporated in the present etching liquid management apparatus capable of collectively processing input functions for inputting setting values and displaying various information such as measurement data and calculation results.

[Operation Example] (Etching solution management method)

Next, the operation of the etching apparatus having the above-described configuration will be described. Hereinafter, an example of using an oxalic acid aqueous solution, which is often used for etching an oxide semiconductor film such as an ITO film, an IZO film, an IGO film, or the like, or an IGZO film, as an etching liquid, will be described.

The etching liquid stored in the etching tank 1 is supplied to the etchant spray 7 through the circulation line 10 and sprayed from the etchant spray 7 while operating the liquid transfer pump 8. Whereby the surface of the substrate 6 conveyed by the roller conveyer 5 is etched. The etching solution is maintained at, for example, 35 DEG C to maintain a predetermined etching rate.

The etchant after the etching drops into the etching tank 1 and is again stored and supplied to the etchant spray 7 through the circulation duct 10 as described above and is sprayed from the etchant spray 7.

For example, when the etchant maintained at 35 占 폚 is sprayed, water is preferentially evaporated. Therefore, the concentration of oxalic acid in the etching solution increases. Oxalic acid dissolves indium to be consumed as oxalic acid ion and indium ion. Nevertheless, since the evaporation amount of moisture is large, oxalic acid is concentrated and the etching rate is increased. In addition, by repeating the etching, indium eluted by etching from the substrate surface is accumulated as the dissolved metal in the etching solution. When the concentration of the dissolved metal in the etching solution increases, dissolution of the metal component on the surface of the substrate is suppressed, so that deterioration of the etching performance of the etching solution is invited. Such etching causes variations in the etching performance due to an increase in the acid concentration of the etching solution and an increase in the concentration of the dissolved metal. Therefore, the following control is performed to prevent the fluctuation of the etching solution.

First, the conductivity value, which is a physical property value correlated to the concentration of oxalic acid in the etchant, is measured in the measurement part E (conductivity measurement step). The etchant used repeatedly in the etching process is continuously sampled continuously by the sampling pipe 31 and the sampling pump 32 and supplied to the measuring section E. The electric conductivity value of the etching liquid is detected by the conductivity meter 17 in the sampled etching liquid.

The conductivity meter 17 receives the command from the computer 30 and repeats the measurement at a predetermined interval to detect the conductivity value of the etchant and returns measurement data to the computer 30. [ In the computer 30, a 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 the oxalic acid concentration of the etching liquid is calculated based on the correlation value from the detected conductivity value.

In the computer 30, the concentration of oxalic acid in the etchant, which is always monitored, is compared with its control value and maintained at a predetermined control value to control replenishment of the replenishment liquid (replenishment control process for oxalic acid concentration).

The control may employ various control methods such as proportional control, integral control and differential control, but it is preferable to use PID (Proportional Integral Derivative) control in which these control methods are combined. When the appropriate PID parameters are set in the computer 30, the oxalic acid concentration is controlled so as to be appropriately maintained at a predetermined management value.

When the concentration of oxalic acid in the etching solution has decreased, the flow rate control valve 27 provided in the middle of the piping from the oxalic acid stock solution supply cylinder 23 is opened to supply, for example, the oxalic acid stock solution by the control command calculated by the computer 30, The necessary amount of undiluted solution is supplied. In the case where the concentration of oxalic acid in the etching solution has risen, the flow control valve 28 installed in the middle of the pure water pipe installed in the base is opened to supply, for example, pure water by the control command calculated by the computer 30, (Pure water) is supplied to the required amount. In this way, the oxalic acid concentration of the etchant is controlled so as to be returned to the control value when the oxalic acid concentration deviates from the control value while being constantly monitored, and is controlled to be maintained at the predetermined control value.

When the concentration of oxalic acid in the etchant does not decrease, the oxalic acid stock solution feeder 23 and the flow control valve 27 are unnecessary, and when there is no increase in the concentration of oxalic acid, And the flow control valve 28 are unnecessary.

In the state where the concentration of oxalic acid is maintained at a predetermined management value, a density value corresponding to the dissolved metal concentration is measured (density measurement step). On the other hand, as described above, since the replenishing liquid is supplied so that the etchant is continuously sampled continuously at a predetermined management value, the oxalic acid concentration is always maintained at a predetermined management value. The etching liquid is continuously sampled continuously by the sampling piping 31 and the sampling pump 32 and supplied to the measuring section E to measure the density value by the density meter 18. The density meter 18 measures the density value of the etching liquid The density value is detected.

The density meter 18 receives the command from the computer 30 and repeats the measurement at a predetermined interval to detect the density value of the etchant and returns measurement data to the computer 30. [ The computer 30 has a correlation (for example, a linear relationship) between the concentration and the density value of any one of the indium concentration, gallium concentration, or zinc concentration of the etchant in which the concentration of oxalic acid previously obtained is maintained at the control value At least one of the indium concentration, the gallium concentration or the zinc concentration of the etching solution is calculated from the detected density value held as the calibration curve based on the correlation.

In the computer 30, control is performed to replenish the replenishing liquid so that the concentration of indium, gallium, or zinc dissolved in the etchant that is always monitored is below the threshold value of the managed concentration compared with their control value Concentration replenishment liquid feeding control process).

In the case where the dissolved metal concentration of the etching liquid has risen, the flow control valve 26 from the etching fresh fluid feed cylinder 22 is opened to supply, for example, an etching fresh fluid by a control command calculated by the computer 30, (Fresh liquid) is supplied as needed. In this way, the concentration of the metal dissolved in the etching solution is controlled so that the concentration of the metal dissolved in the etching solution is kept below the threshold value when the concentration of the dissolved metal exceeds the controlled threshold while being constantly monitored.

The oxalic acid concentration of the etchant in the etching treatment tank 1 and the concentration of the dissolved metal can be controlled within a certain range by the control by the computer 30 described above. For example, it is possible to control the concentration of oxalic acid and the concentration of dissolved metal in the etching solution in the etching treatment tank 1 within a certain range, for example, when the concentration of oxalic acid increases and the concentration of dissolved metal increases during etching by the etching treatment section A It becomes.

[Etching membrane]

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

[Etching solution]

An etching solution containing at least oxalic acid may be used as the etching solution which can be employed in the present embodiment.

[Second Embodiment]

The etching solution management device of the second embodiment of the present invention is a device for managing the etching solution of the etching solution management device of the first embodiment from the conductivity value measured by the conductivity meter 17 and the density value measured by the density meter 18, (Component concentration calculation means) for calculating at least one concentration of the concentration of oxalic acid in the etching solution and the concentration of indium dissolved in the etching solution, the concentration of gallium or the concentration of zinc. The same etching treatment apparatus as that of the first embodiment shown in Fig. 1 can be used as the etching treatment apparatus including the etching solution management apparatus of the second embodiment.

The etching solution containing metal components eluted from the etching film is usually composed of various components such as an acid component, a molten metal component, and an additive component such as a surfactant. Therefore, like the etchant management apparatus described in the first embodiment, under the condition that the concentration of oxalic acid is maintained at a predetermined value, the indium concentration, the gallium concentration, or the zinc concentration, In general, the physical property values of the etchant to be measured do not correlate only to the concentrations of the specific components, although a correlation such as a linear relationship can be obtained within a predetermined concentration range. Although the conductivity value of the etchant correlated to the concentration of oxalic acid strongly depends on the concentration of oxalic acid, it is more strictly attributed to other electrolytic components. Further, even though the density value of the etching solution, which is dependent on the concentration of the metal dissolved in the etching solution, strongly depends on the concentration of the dissolved metal, it is more strictly also contributed by other components. Therefore, from the viewpoint of more precisely managing the component concentration of the etching solution, it is indispensable to treat the measured physical property value of the etching solution as not only the concentration of the specific component to be detected but also the concentration of the other component. By using this point multivariate analysis method, for example, the multiple regression analysis method, it is possible to more accurately calculate the concentration of each component that affects the physical properties of a plurality of measured etchants.

The etching solution management device of the present embodiment is mainly applied to the case where it is necessary to more precisely measure, control and manage the concentration of oxalic acid and the concentration of dissolved metal in the etching solution in the etching treatment. The concentration of oxalic acid and the concentration of dissolved metal A multivariate analysis method (for example, a multiple regression method) is employed in the calculation method. In the first embodiment, at least one of the concentration of indium dissolved in the etching solution, the concentration of gallium, or the concentration of zinc is measured while the concentration of oxalic acid in the etching liquid is a controlled concentration range. In the present embodiment, the multivariate analysis method (Multiple regression analysis method), the concentration of at least one of the oxalic acid concentration, the indium concentration, the gallium concentration or the zinc concentration of the etching liquid can be obtained from the conductivity value and the density value. Therefore, in the second embodiment, the indium concentration, the gallium concentration, or the zinc concentration is controlled so that the concentration of oxalic acid is controlled within the range of the oxalic acid concentration based on at least one of the oxalic acid concentration, the indium concentration, the gallium concentration, (Replenishment liquid feed control step) of the replenishing liquid so that the concentration of the replenishing liquid becomes equal to or less than the threshold value of the concentration of the replenishing liquid. Control of the replenishing liquid, and other constitutions are the same as those in the first embodiment, so that the description thereof will be omitted.

[Multicomponent operation method]

When the indium is dissolved in the oxalic acid aqueous solution by the experiment, the present inventor found that the measured values of the conductivity and the density of the oxalic acid aqueous solution are not as sensitive as one component of the oxalic acid concentration and the soluble indium concentration, It was found that the concentration can be obtained more accurately.

As a result of the research and analysis based on the correlation, the inventors of the present invention conducted linear least-likelihood analysis (MLR-I) from the two kinds of characteristic values (the conductivity value and the density value of the oxalic acid aqueous solution in which at least one of indium, gallium, (Concentration of oxalic acid and at least one concentration of dissolved indium, gallium, and zinc) of a more accurate etchant (an oxalic acid aqueous solution in which at least one of indium, gallium, and zinc is dissolved) by a multiple linear regression-inverse least squares (ILS) I found out that I can do calculations.

Here, the equation of the regression analysis is exemplified. Multiple regression analysis consists of two steps: calibration and prediction. In the multiple regression analysis of the n-component system, m calibration standard solutions shall be prepared. The concentration of the jth component in the i-th solution is denoted by C _ij . Here, i = 1 to m and j = 1 to n. For each of the m standard solutions, p characteristic values (for example, absorbance at any wavelength, conductivity or density) A _ik (k = 1 to p) are measured. Concentration data and characteristic value data can be represented by matrix type (C, A), respectively.

The relationship matrix of this matrix is represented by the calibration matrix and good, here the symbol S (S _kj ; k = 1 to p, j = 1 to n).

& Quot; (2 ) & quot ;

C = A · S

The known C and A (A contents may be mixed with heterogeneous measured values as well as identical measured values, for example, conductivity and density.) Calculating S by matrix operation is a correction step to be. In this case, p> = n, and m> = np. Since each element of S is unknown, it is preferable that m > np. In this case, the following least squares operation is performed.

& Quot; (3 ) & quot ;

Where T is the transpose matrix and -1 is the inverse matrix.

When the concentration of Cu (C _uj ; j = 1 to n), which is to be obtained by multiplying S by the value of p, is determined for Au ( _Auk ; k = 1 to p) Can be obtained.

& Quot; (4 ) & quot ;

Cu = Au · S

This is a prediction step.

The present inventor made one of a plurality of calibration standard solutions by using a sample solution simulating an indium-dissolved oxalic acid aqueous solution as shown in Table 1 above to obtain a calibration matrix in the remaining standard solution, and the concentration of the unknown sample And MLR-ILS calculation was performed by a method (one-out cross-validation method) in which the concentration was compared with the concentration (weight preparation value) of the known liquid. The calculation results are shown in Table 2. Table 2 shows the concentration of oxalic acid and indium obtained from measurements of conductivity and density.

Sample
No.         Weight Preparation Value   Leave-One-Out Predicted Value            Difference Oxalic acid concentration
(wt%) Indium concentration
(ppm) Oxalic acid concentration
(wt%) Indium concentration
(ppm) Oxalic acid concentration
(wt%) Indium concentration
(ppm)  A-1      3.4000       0.00       3.4029       -2.26       0.0029        -2.26  A-4      3.3000     200.17       3.3009      162.54       0.0009       -37.63  A-5      3.5000     200.17       3.5065      157.14       0.0065       -43.03  B-1      3.5000       0.00       3.4973       19.66      -0.0027        19.66  B-3      3.6000     150.13       3.5957      160.02      -0.0043         9.90  B-5      3.2000     174.94       3.1954      191.97      -0.0046        17.03  C-1      3.3853       0.00       3.3855      -16.33       0.0002       -16.33  C-2      3.4191      24.98       3.4173       36.00      -0.0018        11.02  C-3      3.3992      39.99       3.3979       33.47      -0.0013        -6.53  C-4      3.3764      55.01       3.3766       94.48       0.0002        39.47  C-5      3.4318      70.02       3.4328       43.31       0.0010       -26.71  C-6      3.3400      79.98       3.3401       87.45       0.0001         7.46  C-7      3.3587     105.01       3.3567      124.20      -0.0020        19.19  C-8      3.4583      84.99       3.4552       86.06      -0.0031         1.07  C-9      3.4500     184.99       3.4460      211.44      -0.0040        26.45  C-10      3.4388     224.98       3.4350      249.87      -0.0038        24.89  C-11      3.3561     234.99       3.3550      221.05      -0.0011       -13.94  C-12      3.3875     139.99       3.3921      169.30       0.0046        29.30  C-13      3.4100     169.98       3.4146      159.75       0.0046       -10.23  C-14      3.3861     220.02       3.3908      176.36       0.0042       -43.66   Standard Deviation       0.0032        24.04

The calibration matrix at this time is shown in Table 3.

      Concentration of oxalic acid (wt%)        Indium concentration (ppm)         Conductivity            0.105932             -373          density            -27.1591            845610

By the calculation using the multiple regression analysis based on the above experiment, the present inventors found that when the conductivity of the etching solution is within a predetermined range (for example, 55.00 ± 2.5 (mS / cm)), the standard deviation of the dissolved indium concentration is about 24 And the standard deviation of oxalic acid concentration can be calculated with accuracy of about 32 (ppm).

On the other hand, in the present embodiment, the multi-component arithmetic operation method is realized by the arithmetic function of the computer 30. [ That is, if a computer 30 is provided with an operation program of a multivariate analysis method (for example, a multiple regression analysis method) in advance, the computer 30 is connected to the conductivity meter 17 and the density meter 18, The oxalic acid concentration and the dissolved metal concentration of the etching liquid can be calculated by the arithmetic program.

The operations after the oxalic acid concentration and the dissolved metal concentration of the etching liquid in this embodiment are calculated are the same as those in the first embodiment, and a description thereof will be omitted.

[Method for measuring concentration of ingredient]

The present embodiment can be used as a component concentration measuring method for measuring the component concentration in the etching solution.

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

The component concentration in the etching solution can be obtained with high accuracy by calculating the component concentration in the etching solution by the multi-component calculation method.

One… Etching treatment tank, 2 ... Overflow condition,
6 ... Substrate, 7 ... Etchant spray,
8… Pumping pump, 10, 12 ... Circulation duct,
11 ... Circulation pump, 17 ... Conductivity meter,
18 ... Density meter, 20 ... Liquid discharge pump,
21 ... An etchant stock solution feeder ((replenishment solution) feeder)
22 ... An etching fresh liquid supply tank ((replenishment solution) supply tank),
23 ... Oxalic acid stock solution supply bottle ((replenishment solution) supply bottle),
24 ... Piping, 25, 26, 27 ... Flow control valve,
28 ... Flow control valve (pure water supply valve), 29 ... Joining duct,
30 ... Computer, 31 ... Sampling piping,
32 ... Sampling pump, 33 ... Return pipe,
100 ... Etching processing mechanism

Claims (5)

1. An etchant management apparatus for managing an etchant containing oxalic acid, the etchant being used for etching an etched film containing at least one of indium, gallium, and zinc;
A conductivity meter for measuring a conductivity value of the etchant;
A density meter for measuring a density value of the etchant;
Based on the correlation between the oxalic acid concentration and the conductivity value of the etchant and the measurement result of the conductivity meter, the oxalic acid concentration is a correlation between the concentration and the density value of either the indium concentration, the gallium concentration or the zinc concentration of the etchant Based on the relationship between the concentration value of one of indium concentration, gallium concentration, or zinc concentration of the etchant and the density value, and the indium concentration, the gallium concentration Or liquid replenishment control means for controlling the replenishment of the replenishing liquid fed to the etchant so that the concentration of at least one of the zinc concentrations becomes equal to or less than a threshold value of the controlled concentration. 1. An etchant management apparatus for managing an etchant containing oxalic acid, the etchant being used for etching an etched film containing at least one of indium, gallium, and zinc;
A conductivity meter for measuring a conductivity value of the etchant;
A density meter for measuring a density value of the etchant;
A concentration of at least one of an oxalic acid concentration of the etchant and an indium concentration, a gallium concentration, or a zinc concentration of the etchant is determined by a multivariate analysis method based on the conductivity value measured by the conductivity meter and the density value measured by the density meter A component concentration calculating means for calculating the component concentration;
Wherein the concentration of oxalic acid in the etching solution calculated by the component concentration calculating means is within a controlled concentration range and the concentration of at least one of the indium concentration, Liquid replenishment control means for controlling the replenishment of the replenishment liquid fed to the etchant. 1. An etchant management method for managing an etchant containing oxalic acid, the etchant being used for etching an etched film containing at least one of indium, gallium, and zinc;
A conductivity measuring step of measuring a conductivity value of the etchant;
Based on the correlation between the concentration of oxalic acid in the etchant and the conductivity value and the measurement result of the conductivity measurement step, the concentration of oxalic acid is set to a value between the concentration and the density value of either the indium concentration, the gallium concentration or the zinc concentration of the etchant A liquid replenishment control step for controlling the liquid feed (replenishment) of the replenishing liquid replenished to the etchant so that the concentration of the oxalic acid is within the correlation range;
A density measurement step of measuring a density value of the etchant in which the concentration of oxalic acid is controlled within the concentration range by the replenishment liquid supply control step for the oxalic acid concentration;
At least one of the indium concentration, the gallium concentration, or the zinc concentration, based on a correlation between the density and the concentration of either the indium concentration, the gallium concentration, or the zinc concentration of the etchant and the measurement result of the density measurement process (Liquid feed) of the replenishing liquid replenished to the etchant so that the concentration of the replenishing liquid is controlled to be equal to or less than the threshold value of the controlled concentration. 1. An etchant management method for managing an etchant containing oxalic acid, the etchant being used for etching an etched film containing at least one of indium, gallium, and zinc;
A conductivity measuring step of measuring a conductivity value of the etchant;
A density measurement step of measuring a density value of the etchant;
Based on the conductivity value measured by the conductivity measuring step and the density value measured by the density measuring step, the concentration of oxalic acid in the etching solution and the concentration of at least one of the indium concentration, gallium concentration or zinc concentration of the etching solution A component concentration calculating step of calculating a concentration;
Wherein the concentration of oxalic acid in the etching solution calculated by the component concentration calculating step is within a controlled concentration range and the concentration of at least one of indium concentration, gallium concentration, or zinc concentration in the etching solution is not more than a threshold value And a replenishment liquid feeding control step of controlling the feeding of the replenishing liquid fed to the etching liquid. An electric conductivity measuring step of measuring an electric conductivity value of an etchant used for etching an etched film containing at least one of indium, gallium or zinc, the etchant containing oxalic acid;
A density measurement step of measuring a density value of the etchant;
Based on the conductivity value measured by the conductivity measuring step and the density value measured by the density measuring step, the concentration of oxalic acid in the etching solution and the concentration of at least one of the indium concentration, gallium concentration or zinc concentration of the etching solution And a component concentration calculating step of calculating a concentration of the component.

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