JP2013181219A - Etchant regenerating apparatus and etchant regenerating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To regenerate an etchant including at least a copper ion, a sulfate ion, hydrogen peroxide, and one or more acids.SOLUTION: A copper-ion-concentration measuring device 2 serving as a copper-ion-concentration measuring means for measuring a copper ion concentration and a chelate resin tower 4 serving as a copper ion removal means for removing an copper ion in a used etchant 1 through the use of a chelate resin 36 are included, and sulfuric acid 10 is used as a regenerating solution to regenerate the chelate resin 36. As a result, waste solution is reduced as much as possible and mixing of impurities into the etchant and the sulfric acid 10 which causes the waste solution and causes regeneration to be difficult can be prevented. In addition, an apparatus and method can be provided for regenerating the etchant with a simple device and measuring instrument at low cost.

Description

  The present invention relates to an etching solution regeneration method and an etching solution regeneration apparatus.

  Conventionally, aluminum has been used for wiring such as flat display panels, but copper with lower electrical resistance has been used in order to solve problems such as signal delay with the increase in display size and resolution. Yes.

  When wet etching is used as a method for performing copper wiring for displays, an etching solution is required, but since fine processing accuracy is required for the copper wiring shape, it is conventionally used for etching printed circuit boards and the like. An etchant different from the etchant that has been developed has been developed (see, for example, Patent Document 1).

  In order to regenerate such an etching solution, it is necessary to remove copper in the etching solution and to replenish consumed chemical substances.

  As a conventional method, for example, in an etching solution mainly composed of ferric chloride, the etching solution is regenerated by adsorbing and removing the metal dissolved by the cation exchange resin (see, for example, Patent Document 2). ).

  Further, in the cuprous chloride-containing etching solution, copper is recovered at the cathode by the diaphragm electrolysis method, and the etching solution is regenerated by utilizing the chlorine gas generated at the anode (see, for example, Patent Document 3). ).

  In addition, an etching solution containing sulfuric acid and hydrogen peroxide is regenerated by decomposing hydrogen peroxide, electrodepositing dissolved copper, and collecting sulfuric acid (see, for example, Patent Document 4).

  In either case, the copper dissolved in the etching solution is removed by some means, and then the etching solution is regenerated by adding components as necessary.

JP 2002-302780 A JP-A 61-149485 Japanese Patent Laid-Open No. 5-117879 JP 2000-129472 A

  However, the etching solution for copper wiring used in flat panel displays is used to prevent reprecipitation of dissolved copper and to control the etching rate of copper, compared with the etching solution used for copper wiring on printed circuit boards. For this purpose, more diverse ingredients are included.

  In particular, as a method for controlling the etching rate of copper, in the etching solution in which the etching rate is reduced by containing copper ions in the etching solution from the start of use, the etching solution is reduced by the conventional method or the like. It is not easy to regenerate.

  For example, when a cation exchange resin is used as in Patent Document 1, in order to remove and remove a certain amount of copper ions in the etching solution, the flow rate of the etching solution passing through the cation exchange resin is used. Since it must be changed according to the concentration of the used etching solution and the amount of copper adsorbed on the cation exchange resin, there is a problem that a certain amount of etching solution cannot be regenerated per time.

  Even if copper is removed by an electrodeposition method as in Patent Document 2, there is a problem that the dissolved copper cannot be removed because of oxidative dissolution by etching.

  In the method of electrodepositing copper after decomposing an oxidizing agent as in Patent Document 3, the oxidizing agent is wasted, so that there is a problem that it is inefficient as an etching solution regeneration.

  As described above, the etching solution for copper wiring used in the flat panel display has a problem that the conventional method cannot remove the dissolved copper with high efficiency and it is difficult to regenerate the etching solution. ing.

  Therefore, in the present invention, in a copper etching solution containing at least copper ion, sulfate ion, hydrogen peroxide and one or more acids, the dissolved copper is removed with high efficiency, and a means for removing copper is easily regenerated, An object of the present invention is to provide an etching solution regenerating apparatus and an etching solution regenerating method that reduce waste liquid and the like as much as possible.

  In order to solve the above-described conventional problems, an etching solution regenerating apparatus according to the present invention is an etching solution regenerating apparatus that regenerates a copper etching solution containing at least copper ions, sulfate ions, hydrogen peroxide, and one or more acids. And a copper ion concentration measuring means for measuring the copper ion concentration in the etching solution, and a copper ion removing means for removing the copper ion in the etching solution using a chelate resin. An etching solution regenerating apparatus that regenerates the copper ion removing means using sulfuric acid when the measured copper ions in the etching solution have a concentration higher than a preset value.

  With this configuration, excess copper ions after etching from an etchant containing at least copper ions, sulfate ions, hydrogen peroxide, and one or more acids are removed with a chelate resin, and the chelate resin is regenerated with sulfuric acid. This makes it possible to regenerate the etching solution and regenerate the chelate resin that removes copper ions.

  According to the present invention, the regeneration of an etchant containing at least copper ions, sulfate ions, hydrogen peroxide, and one or more acids reduces the waste liquid as much as possible, and the etching and sulfuric acid make it difficult to cause and regenerate the waste liquid. It is possible to prevent contamination of impurities.

Block diagram of the etching solution regeneration apparatus of the first embodiment Block diagram of the etching solution regenerating apparatus of the second embodiment Schematic of the etching solution regenerating apparatus of Embodiment 3 The figure which shows the copper ion density | concentration of the used etching liquid of Embodiment 3. Figure showing the concentration of copper ions in sulfuric acid during regeneration

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 shows a block diagram of an etching solution regenerating apparatus according to the present invention.

  There are many types of etchants for etching copper, such as ferric chloride, cupric chloride, and ammonium peroxodisulfate. The inventors of the present invention include at least copper ions, sulfate ions, hydrogen peroxide. For an etchant containing one or more acids, it is possible to use a chelate resin as a means for removing copper ions from the used etchant after etching, and to use sulfuric acid as a regenerating solution for regenerating the chelate resin to minimize waste liquid. In addition, the present inventors have found that the cause of waste liquid and the etching that makes it difficult to regenerate and the contamination of sulfuric acid are prevented.

  In the first embodiment, a case will be described in which the copper concentration in the used etching solution increases while the concentration of the chemical solution described later does not change significantly until the etching performance is lowered.

  The used etching solution here does not mean that it is unsuitable as an etching solution, but an etching solution that passes through the etching process even once and has a concentration slightly higher than the copper ion concentration of the initial etching solution. In the case where the copper ion concentration is lower than the preset concentration, it is not necessary to remove the copper ion, and an etching solution in which the copper ion needs to be removed when it is higher is shown.

  The chemical solution is a component excluding copper ions contained in the etching solution, and maintains etching performance such as hydrogen peroxide, sulfate ions, one or more acids, chelating agents, and hydrogen peroxide decomposition inhibitors. It is a necessary ingredient for this.

  The spent etching solution 1 is a chelate resin as a copper ion removing means by a flow rate splitter 3 that can adjust the flow rate of a plurality of flow paths after measuring copper ions with a copper ion concentration measuring device 2 as a copper ion concentration measuring means. The flow path A that does not pass through the tower 4 and the flow path B that passes through the chelate resin tower 4 are divided.

  The chelate resin packed in the chelate resin tower 4 includes styrene and styrene-divinylbenzene copolymer as a base material, and chelate species include iminodiacetic acid, polyamine, aminocarboxylic acid, amine phosphate, and amide. There is an oxime type or the like, but any chelate resin may be used as long as it selectively removes copper ions and does not cause deterioration in performance or deterioration due to components such as hydrogen peroxide and acid. In particular, iminodiacetic acid-based and aminocarboxylic acid-based chelating resins are excellent in copper ion removal selectivity, have high removal performance, and are not easily deteriorated.

  The used etching solution 1 flowing through the flow path B passes through the chelate resin tower 4, then passes through the copper ion concentration measuring device 5, and is mixed with the used etching solution 1 that has passed through the flow path A in the mixing tank 6. The The mixing tank 6 may be any means as long as it can mix the etching solution flowing from the flow path A and the flow path B, and the means is not limited.

  In the mixing tank 6, a used etching solution having a high copper ion concentration and a used etching solution from which copper ions have been removed are mixed, and the copper ion concentration of the etching solution when the respective flow rates adjusted by the flow rate splitter 3 are mixed is set. The concentration is set so that the concentration is the same (such as the copper ion concentration of the etchant when new). Therefore, the solution discharged from the mixing tank 6 becomes the regenerated etching solution 7 and is used in the etching process.

  In the chelate resin tower 4, the copper ion removal performance is reduced, and the copper ion concentration measured by the copper ion concentration measuring device 5 of the effluent of the chelate resin tower 4, that is, the etching liquid from which copper ions have been removed, is higher than the preset concentration. When the concentration is too high, the flow splitter 3 stops the flow of the used etching solution 1 into the chelate resin tower 4 as the flow path B, or stops the flow path A. Thereafter, water 8 is allowed to flow into the chelate resin tower 4 and the chelate resin is washed with water.

  This washing with water is performed to wash away the components of the etching solution remaining in the chelate resin tower 4, and the solution discharged from the chelate resin tower 4 at that time is stored in the waste liquid tank 9 and discarded. However, if the amount of water is small and there are no problems such as impurities, it is possible to flow into the mixing tank 6.

  Next, sulfuric acid 10 is allowed to flow into the chelate resin tower 4 to regenerate the chelate resin, and the sulfuric acid 10 containing high-concentration copper ions after regeneration is stored in the electrodeposition tank 11. Alternatively, it can be discarded.

  Immediately after the sulfuric acid 10 has flowed into the chelate resin tower 4, only the water remaining in the chelate resin tower 4 is discharged and the copper ion concentration is low, so the discharged solution may be discarded or regenerated. It can also be used as sulfuric acid.

  Of course, in this case, it is necessary to prepare the sulfuric acid 10 at a concentration suitable for regeneration. Since the sulfuric acid 10 having a high copper ion concentration becomes a copper sulfate solution with few impurities, it is stored in the electrodeposition tank 11, and then metal copper is deposited on the electrode plate by electrodeposition for recovery as metal copper. Since the solution after electrodeposition is sulfuric acid 10 having a low copper ion concentration, it can be used again as sulfuric acid 10 for regeneration.

  The concentration of the sulfuric acid 10 for regeneration used here determines an optimum concentration according to the characteristics, volume and flow rate of the chelate resin. Usually, 1 to several mol / L is used. In addition, when the water 8 and the sulfuric acid 10 are allowed to flow in, although not shown, it is performed by a device that can adjust the flow rate using a pump, a solenoid valve or the like.

  For an etchant containing at least copper ions, sulfate ions, hydrogen peroxide, and one or more acids, a chelate resin that selectively removes copper ions is used as a means for removing copper ions from the used etchant after etching. Therefore, components other than copper ions contained in the etching solution are difficult to be removed or decomposed by the chelate resin, and since there is no elution from the chelate resin, etching components other than copper ions can be retained, and impurities Can also be prevented.

  Moreover, since sulfuric acid is used as a regenerating solution for regenerating the chelate resin, the components of the regenerated solution are basically water, sulfate ions, hydrogen ions, and copper ions, and therefore are components contained in the etching solution. In addition to having little effect on etching performance, copper can be easily recovered by electrodeposition of the regenerated solution, and some copper ions remain in the solution after electrodeposition. It can be reused by mixing with sulfuric acid.

  Therefore, at least copper ions, sulfate ions, hydrogen peroxide, an etchant containing one or more acids, a chelate resin, a combination of sulfuric acid, or a combination of electrodeposition reduces the waste liquid as much as possible when regenerating the etchant. In addition, the present inventors have found that the effects of waste liquid and the etching that makes it difficult to regenerate and the mixing of impurities into sulfuric acid can be prevented, and the cost and cost can be reduced with a simple apparatus and measuring instrument.

  For example, even if hydrochloric acid is used as the chelating resin regeneration solution, the chelating resin can be regenerated. However, since hydrochloric acid contains chlorine ions, and hydrochloric acid remains in the chelate resin tower after regeneration of the chelate resin, there is a risk that chlorine ions will be mixed into the etchant when the etchant is run unless sufficient water washing is performed. If mixed, it may adversely affect the etching performance.

  For this purpose, not only a copper ion concentration measuring device but also a chlorine ion concentration measuring device capable of measuring to an extremely low concentration is required. Alternatively, if electrodeposition is performed with hydrochloric acid containing copper ions after regeneration, chlorine gas may be generated. For example, combinations other than those shown above take a very long time for washing with water, and extra measurements. Equipment is required and the method of recovering final copper is also costly and can only be done with limited methods, resulting in equipment complexity and cost.

  In the block diagram of the etching solution regenerating apparatus described above, the etching solution flowing through the flow path A passes through the copper ion concentration measurement step → the flow rate setting step → the mixing step, and the etching solution flowing through the flow channel B is the copper ion concentration measurement step. → Flow rate setting process → Copper ion removal process → Copper ion concentration measurement process → Mixing process, during regeneration, the water flowing through the channel B is washed with the chelate resin tower 4 in the water washing process → Copper ion concentration measurement process → Waste liquid process, then Also, the etching solution regeneration method in which the sulfuric acid flowing through the flow path B passes through the regeneration step of the chelate resin tower 4 → the copper ion concentration measurement step → the copper recovery step (electrodeposition step) is also shown.

  That is, the flow rate is adjusted in the flow rate setting step in which the flow rate of the etching solution when the copper ion measured in the copper ion measurement step is equal to or higher than the preset concentration flows in two or more according to the concentration. Then, one channel flows to the mixing step, one channel flows to the copper ion removal step which is a chelate resin tower, and the etching solution from which the copper ions have been removed flows to the mixing step to remove the copper ions. Mix with not etchant.

  A copper ion concentration measurement step is provided downstream of the copper ion removal step, and when the copper ion concentration of the etching solution discharged from the copper ion removal step exceeds a preset concentration, the copper ion removal is performed in the flow rate setting step. The flow of the etching solution to the process is stopped, water is allowed to flow into the chelate resin tower 4 from another flow path, and the chelate resin tower 4 is washed with water and the solution discharged from the chelate resin tower 4 at the time of water washing A copper ion concentration measuring step for measuring the copper ion concentration and a waste liquid step for discarding the solution are provided.

  A regeneration step of stopping the inflow of water when the copper ion concentration exceeds a preset concentration and allowing sulfuric acid to flow into the chelate resin tower 4 from another flow path to regenerate the chelate resin that removes copper ions. And a copper ion concentration measuring step for measuring the copper ion concentration of the solution discharged from the chelate resin tower 4 during regeneration, and a copper recovery step for recovering metallic copper from the solution, and the copper discharged from the chelate resin tower 4 When the ion concentration becomes equal to or lower than a preset concentration, the inflow of sulfuric acid is stopped, and an etching solution having a first preset copper ion concentration is allowed to flow, and the above steps are repeated.

  In such a method of regenerating an etchant containing at least copper ions, sulfate ions, hydrogen peroxide, and one or more acids, the copper ion removal step of removing copper ions uses a chelate resin, It is important to use sulfuric acid as a regenerating solution for regenerating the chelate resin.

  Although the above-described regenerating apparatus and regenerating method both have a copper ion removing means or a chelate resin tower which is a copper ion removing process, one case has been described. The tower can be washed and regenerated. Further, after the regeneration, a means or a process may be added for further flowing water through the chelate resin tower and washing it with water to wash away impurities contained in sulfuric acid, thereby preventing impurities from being mixed into the etching solution.

  Although the copper ion concentration measuring device 2 shown in the drawing is shown as an in-line measuring device, it may be measured offline by sampling the etching solution flowing through the flow path B at a constant interval.

  For example, off-line measurement is preferable when the copper ion concentration is stable, and in-line measurement is preferable when the copper concentration is unstable. Only one sample ring is used downstream of the used etching solution by using one copper ion concentration measuring device. You may provide in the downstream of the side and a copper ion removal apparatus.

  In addition, the copper ion concentration is measured, and the adjustment of the flow rate of the etching solution and the subsequent washing and regeneration are controlled according to the set concentration. If it is known, the time may be controlled.

Proportions spent etchant 1 is divided by the flow splitter 3, the flow path after passing through the copper ion concentration C _x0 spent etching solution 1, the copper ion concentration C _x1 playback etching solution 7, a copper ion removal device If the ratio of flowing through the flow path A is represented by r _xA, which is determined by the copper ion concentration C _xB of B, the ratio of flowing through the flow path B can be represented by 1−r _xA . Since the flow rate splitter 3 can adjust the flow rates of the plurality of flow paths, it can automatically or manually adjust the flow rates flowing through the flow paths A and B from the calculated ratio.

  Further, these relationships can be expressed by Equation 1.

The copper ion concentration C _x1 of the regenerative etching solution 30 is a constant value and is therefore always constant. Therefore, the copper ion concentration C _x0 of the used etching solution 1 and the copper ion concentration C _xB of the flow path B after passing through the copper ion removing device 4 are measured by the copper ion concentration measuring device 2 and the copper ion concentration measuring device 5, respectively. By doing so, the ratio r _xA flowing through the flow path A can be controlled.

The concentration of the regenerated etching solution 30 in the first embodiment is controlled by the flow rate splitter 3, and the copper concentration C _x0 of the used etching solution 1 and the copper concentration C _xB of the flow path B after passing through the copper removing device. Using the measured values, the flow rate through the flow path A and the flow path B is set by controlling the opening of the valve or the like so that the flow rate through the flow path A calculated in Equation 1 becomes r _A. ing.

In particular, when a chelate resin is used for the copper ion removing device 4, the copper ion concentration C _xB of the flow path B after passing through the chelate resin tower 4 becomes a constant value of 0 or C _x0 >> C _xB. Therefore, the regenerated etching solution 30 can be obtained only by accurately grasping the copper concentration C _x0 of the used etching solution 1.

(Embodiment 2)
FIG. 2 is a block diagram including adjustment of the chemical solution of the etching solution regenerating apparatus of the present invention. The same reference numerals are used for configurations having the same effects as those of the first embodiment, and detailed description thereof is omitted. Moreover, since the apparatus and process which wash and recycle | regenerate the copper ion removal apparatus which is a chelate resin tower are the same as the content shown in Embodiment 1, illustration and description are abbreviate | omitted.

  In the second embodiment, when the copper ion concentration in the used etching solution is increased and the hydrogen peroxide concentration is decreased, that is, by adding a reduced amount of hydrogen peroxide, other than copper ions and hydrogen peroxide. This is a case where the chemical concentration decreases and the etching performance is lowered.

  The used etching solution 21 passes through the chemical concentration measuring device 22 and the copper ion concentration measuring device 2, and then the flow path A that does not pass through the chelate resin tower 4 and the flow path that passes through the chelate resin tower 4 by the flow rate splitter 3. And B. The etching solution flowing through the channel B passes through the chelate resin tower 4, then passes through the copper ion concentration measuring device 5, and is mixed with the etching solution that has passed through the channel A in the mixing tank 6. Thereafter, each chemical solution is removed by the chemical solution adding device 23 excluding hydrogen peroxide so that the chemical solution excluding hydrogen peroxide that has passed through the chemical concentration measuring device 22 and lost in the etching step of the etching solution has a predetermined concentration. Hydrogen peroxide that has been added at a rate and lost in the subsequent stage by the hydrogen peroxide adding device 24 is added by the etching step of the etching solution, and the regenerated etching solution 30 is obtained.

The etching solution containing hydrogen peroxide consumes hydrogen peroxide and etches copper by the following chemical reaction, Chemical Formula 1 and Chemical Formula 2 (where A ⁻ is an anion of an acid pair).

  In addition to this reaction, hydrogen peroxide is consumed by a chemical reaction in which hydrogen peroxide self-decomposes, Chemical Formula 3.

Due to these chemical reactions, hydrogen peroxide is most consumed in the chemical solution contained in the etching solution, so that it is necessary to add hydrogen peroxide to regenerate the etching solution. In this case, by first measuring the hydrogen peroxide concentration with the chemical concentration measuring device 22, the hydrogen peroxide addition amount V _p is the amount V of the regenerated etching solution 30 and the hydrogen peroxide concentration C _p0 of the used etching solution 21. The hydrogen peroxide concentration C _p1 of the regenerated etching solution 30 and the hydrogen peroxide concentration C _{p2 to} be added can be expressed by _Equation 2.

Since the copper ion concentration C _y2 of the etching solution in the mixing tank 6 is diluted by the hydrogen peroxide addition amount V _p and becomes the copper ion concentration C _y1 of the regenerating etching solution 30, these relationships can be expressed by Equation 3. it can.

The ratio r _yA divided into the flow path A by the flow rate splitter 3 is the copper ion concentration C _y0 of the used etching solution 21, the copper ion concentration C _y2 of the etching solution in the mixing tank 6, and after passing through the chelate resin tower 4. determined by copper ion concentration C _yB of the flow path B, to represent the percentage of flow through the flow path a in r _yA, the proportion flowing through the channel B can be expressed by 1-r _yA, their relationships,

By combining with Equation 2 and Equation 3, it can be expressed as Equation 5.

As described above, the ratio of passing through the flow path A and the flow path B can be determined by the concentrations of copper ions and hydrogen peroxide at each location. Here, the copper ion concentration C _y1 , the hydrogen peroxide concentration C _p1 , and the added hydrogen peroxide concentration C _p2 of the regenerating etching solution 30 are always constant because they are specified values.

Therefore, the copper ion concentration C _y0 and the hydrogen peroxide concentration C _{p0 of} the used etching solution 1 and the copper ion concentration C _yB of the flow path B after passing through the chelate resin tower 4 are respectively obtained from the copper ion concentration measuring device 2 and the chemical solution. By measuring with the concentration measuring device 22 and the copper ion concentration measuring device 5, the ratio _ryA flowing through the flow path A can be controlled.

  Therefore, the copper ion concentration measuring means is at a position where the concentration of the used etching solution 1 and the flow path B after passing through the chelate resin tower 4 can be measured, and the chemical concentration measuring means is the concentration of the used etching solution 1. It is desirable to install at a position where it can be measured.

  In the second embodiment, hydrogen peroxide has been particularly described. However, if the concentration of copper ions changes depending on the amount of chemical solution to be added and affects the etching performance of the regenerated etching solution, an acid, a chelating agent, a peroxide is used. Any chemical solution such as a hydrogen decomposition inhibitor may be used.

  The position of the chemical solution adding device 23 and the hydrogen peroxide adding device 24 excluding hydrogen peroxide may be upstream of the mixing tank 6 in the flow path direction, but the chelate resin gives some change to the chemical solution of the etching solution. When there is a possibility, it is desirable to add at the same time when the flow path A and the flow path B are mixed in the mixing tank 6 or at the downstream side thereof.

  In particular, when the chemical solution to be added is hydrogen peroxide, the hydrogen peroxide adding device 24 is provided on the downstream side of the chemical solution adding device 23 excluding hydrogen peroxide in order to prevent the self-decomposition reaction due to chemical formula 3 as much as possible. It is preferable.

  In the block diagram of the etching solution regenerating apparatus described above, the etching solution flowing through the flow path A passes through the chemical solution concentration measuring step → the copper ion concentration measuring step → the flow rate setting step → the mixing step, and the etching solution flowing through the flow channel B is Chemical solution concentration measurement process-> Copper ion concentration measurement process-> Flow rate setting process-> Copper ion removal process-> Copper ion concentration measurement process-> Etching solution that passes through the mixing process and the flow path A and the flow path B mixed in the mixing process However, an etching solution regeneration method that passes through a chemical solution addition process excluding hydrogen peroxide → a hydrogen peroxide addition process is also shown.

  Although the copper ion concentration measuring device 2, the copper ion concentration measuring device 5, and the chemical concentration measuring device 22 shown in the second embodiment are shown as in-line measuring devices, they may be offline measuring means. It is not intended to limit. When hydrogen peroxide is added even when the concentration of chemicals other than copper ions and hydrogen peroxide decreases by reducing the chemicals other than hydrogen peroxide and the etching performance is reduced. The same effect can be obtained by calculating in the same manner. Even when the chemical solution is reduced by two or more components, it is possible to regenerate the etching solution by adding a calculation in the same way as in the second embodiment.

(Embodiment 3)
FIG. 3 shows a schematic diagram of the etching solution regenerating apparatus shown in the first embodiment. The same reference numerals are used for configurations having the same functions and effects as in the first and second embodiments, and detailed description thereof is omitted.

  The used etching solution 1 is placed in a used etching solution tank 31, pumped up by a pump 32 through a pipe, and divided into a flow path A and a flow path B by a flow rate splitter 3. The flow rate splitter 3 uses the variable flow rate valves 34 and 35 to change the flow rate after passing through the three-way branch valve 33. Any means can be used as long as the flow rate flowing through the flow path A and the flow path B can be controlled. The etching solution flowing in the flow path B passes through the chelate resin tower 4 filled with the iminodiacetic acid chelate resin 36 manufactured by Mitsubishi Chemical as copper ion adsorption means, and is sampled in time by the three-way branch valve 37 and collected in the sampling tank 38. To do. In addition, since the copper ion concentration of the actual used etching solution varies considerably, a three-way branch valve for sampling for measuring the copper ion concentration of the used etching solution is required on the upstream side of the flow rate splitter 3. This time, since a used etching solution having a constant copper ion concentration was used, it was omitted. The etching solution that has passed through the channel A and the channel B is mixed in the mixing tank 39.

  A pump 41 for flowing the water 8 stored in the water tank 40 to the chelate resin tower 4 for water washing is provided and connected to the flow path B through a solenoid valve 42 by piping. Similarly, a pump 44 for flowing the sulfuric acid 4 stored in the sulfuric acid tank 43 for regeneration is provided and connected to the flow path B through a solenoid valve 45 by piping. The solution discharged from the chelate resin tower 4 at the time of washing with water is branched from the flow path B, and is piped through the three-way branch valve 46 and stored in the waste liquid tank 9. Similarly, the solution discharged from the chelate resin tower 4 at the time of regeneration branches from the flow path B, and is piped through the three-way branch valve 47 and stored in the electrodeposition tank 11.

  In the above configuration, the operation of the etching solution regenerating apparatus will be described.

  A used etching solution 1 of an aqueous solution of 7.5% hydrogen peroxide, 7.7% citric acid, and 0.2% copper sulfate is caused to flow to the flow splitter 3 by the pump 32 and then to the flow path A and the flow path B, respectively.

  The respective flow rates flowing in the flow channel A and the flow channel B are calculated from the copper ion concentration of the used etching solution 1 described in the second embodiment and adjusted by the flow rate splitter 3, but the copper ion concentration is constant. In this embodiment, since a used etching solution 1 is used, it is not adjusted, and a certain amount is passed through the flow path A and the flow path B without measuring the copper ion concentration. The etching solution flows into the mixing tank 6.

  The copper ion concentration is preferably measured automatically by an in-line method. However, in this embodiment, the sample liquid sampled in a timely manner by the three-way branch valve 37 and collected in the sampling tank 38 is UV-visible by JASCO. Using a spectrophotometer V-650, diluted 10-fold with 0.05M EDTA solution, the absorbance at 732 nm was measured, and the copper ion concentration was quantified according to the Lambert-Beer law.

  The sample solution was taken out from the three-way branch valves 46 and 47 not only when copper ions were removed by the normal chelate resin tower 4 but also during washing and regeneration, and the copper ion concentration was measured each time.

  The spent etching solution 1 that has flowed to the flow path B passes through the chelate resin tower 4, and the copper ions are removed by the chelate resin 36. FIG. 4 shows the copper ion concentration of the used etching solution 1 discharged from the chelate resin tower 4 when flowing at an SV value of 5 with respect to the volume of the chelate resin 36.

  As shown in FIG. 4, almost no copper ions were detected in the initial stage after flowing the used etching solution 1, but after about 70 minutes, copper ions were detected and the copper ion concentration gradually increased. The copper ion concentration when the used etching solution 1 is stopped from flowing into the chelate resin tower 4 varies depending on the conditions, but the ratio of the copper ion concentration to the initial concentration is a relative value such as 0.1 or more or 0.2 or more. And the absolute value of the copper ion concentration is set in advance.

  When the copper ion concentration equal to or higher than the set value is indicated, it is determined that the adsorption performance of the chelate resin 36 is insufficient (breakthrough), and the chelate resin tower of the used etching solution 1 is determined by the flow rate splitter 3. Stop the inflow to 4.

  The copper ion concentration shown in FIG. 4 is the copper ion concentration of the used etching solution 1 discharged from the chelating resin tower 4 when the used etching solution 1 is flowed again after washing and regenerating the chelating resin 36 described later. As shown in the figure, the concentration curve (breakthrough curve) hardly changed even when it was repeated 5 times, and stable body ion removal performance was exhibited. Thus, when it shows stable performance, it is used to the chelate resin tower 4 based on the time grasped in advance without frequently measuring the copper ion concentration by performing verification confirmation in advance. Control of etching solution inflow, water washing, regeneration, etc. may be performed.

  Next, the chelate resin tower 4 is washed with water. The electromagnetic valve 42 is opened, and the water 8 is caused to flow into the chelate resin tower 4 with the SV value 10 by the pump 41. Since the chelate resin tower 4 is filled with the used etching solution 1 from which copper ions have been removed, hydrogen peroxide, citric acid, or the like, which is a component thereof, is prevented from being mixed into the regeneration solution during the next regeneration. Wash with water.

  The components of the used etching solution 1 in the chelate resin tower 4 can be removed by inflowing for 30 minutes, the electromagnetic valve 42 is closed, and the inflow of water 8 is stopped. The solution discharged from the chelate resin tower 4 at the time of washing with water is stored in a waste liquid tank 9 and then processed as a waste liquid. The smaller the waste liquid, the better. The shorter the time for flowing water, the smaller the flow rate, the better. However, optimization depends on conditions.

  When the water washing is completed, the chelate resin tower 4 is regenerated. The electromagnetic valve 45 is opened, and 1 mol of sulfuric acid 10 is caused to flow into the chelate resin tower 4 by the pump 44 at an SV value for 120 minutes. The chelate resin tower 4 immediately after washing with water is almost filled with water, but by flowing sulfuric acid 10, the copper ions removed by the chelate resin 36 are replaced with hydrogen ions of the sulfuric acid 10 and discharged from the chelate resin tower 4. The solution becomes a sulfuric acid solution containing copper ions, and the copper ion concentration of the solution is shown in FIG.

  As shown in FIG. 5, after flowing sulfuric acid 10, copper ions are not detected at first, but copper ions are detected after about 25 minutes, reach a peak after about 40 minutes, and copper ions are detected again after about 70 minutes. The concentration was not reached. That is, the regeneration time for allowing the sulfuric acid 10 to flow is about 70 minutes.

  The concentration of copper ions discharged from the chelate resin tower 4 at the time of regeneration when the above-described spent etching solution 1 is introduced and the process of removing the copper ions into the chelate resin tower 4 is repeated five times is almost the same. It can be seen that the chelate resin 36 is stably regenerated.

  The sulfuric acid 10 containing copper ions discharged from the chelate resin tower 4 at the time of regeneration is stored in an electrodeposition tank 11 for recovery as metallic copper. When regeneration is finished (when copper ions are no longer detected or at that time), the electromagnetic valve 45 is closed, the flow of sulfuric acid 10 is stopped, and the spent etching solution 1 is again chelated by the flow splitter 3. By flowing into the tower 4 and thereafter repeating the same operation, the etching solution can be regenerated by removing the copper ions from the etching solution and regenerating the chelate resin.

  When the regeneration is finished, the chelate resin tower 4 is filled with sulfuric acid 10 containing copper ions. However, even if the spent etching solution 1 is passed through the chelate resin tower 4 immediately after that, sulfuric acid with high purity is used. By doing this, the copper ions, sulfate ions, and hydrogen ions originally contained in the used etching solution 1 are only mixed in the used etching solution, and the effect of preventing impurities from being mixed into the etching solution is obtained. can get.

  Further, since the sulfuric acid 10 containing copper ions flowing into the electrodeposition tank 11 contains only copper ions, sulfate ions, and hydrogen ions, it is ideal for reducing copper by electrodeposition and recovering it as metallic copper. Solution.

  Of course, in order to perform electrodeposition, the higher the copper ion concentration, the better. Therefore, as explained in the graph shown in FIG. 5, the solution up to about 25 minutes in which copper ions are not detected is basically sulfuric acid. By using it again as sulfuric acid for regeneration, the amount of sulfuric acid used can be reduced, and the solution discharged by about 25 minutes to about 70 minutes can be used as a solution for electrodeposition. Therefore, it is possible to effectively perform the analysis, and it is possible to recover metallic copper with less power consumption.

  Of course, the electrodeposition tank 11 is not necessarily required, and it is possible to reduce the waste as much as possible by purchasing it as a valuable resource from a specialized supplier as a solution of sulfuric acid 10 containing copper ions.

  In the examples, one chelate resin tower is described, but two or more chelate resin towers may be provided. For example, in two cases, while one chelate resin tower is removing copper ions from the spent etching solution, the other chelate resin tower is washed with water, regenerated, and alternately performed. The used etching solution can be regenerated (copper ion removal).

  The etching solution regeneration apparatus and the regeneration method according to the present invention enable regeneration of an etching solution containing at least copper ions, sulfate ions, hydrogen peroxide, and one or more kinds of acids. It is useful for purchasing etchant used for wiring, reducing waste liquid treatment costs, and reducing environmental impact.

DESCRIPTION OF SYMBOLS 1 Used etching liquid 2 Copper ion concentration measuring device 3 Flow rate splitter 4 Chelate resin tower 5 Copper ion concentration measuring device 6 Mixing tank 7 Regeneration etching liquid 8 Water 9 Waste liquid tank 10 Sulfuric acid 11 Electrodeposition tank 21 Used etching liquid 22 Chemical concentration Measuring device 23 Chemical solution addition device excluding hydrogen peroxide 24 Hydrogen peroxide addition device 30 Regenerated etchant 31 Used etchant tank 32 Pump 33 Three-way branch valve 34 Variable flow valve 35 Variable flow valve 36 Chelate resin 37 Three-way branch valve 38 Sampling Tank 39 Mixing tank 40 Water tank 41 Pump 42 Solenoid valve 43 Sulfuric acid tank 44 Pump 45 Solenoid valve 46 Three-way branch valve 47 Three-way branch valve

Claims (9)

An etching solution regenerating apparatus that regenerates a copper etching solution containing at least copper ions, sulfate ions, hydrogen peroxide, and one or more acids, and measures the copper ion concentration in the etching solution. And copper ion removing means for removing copper ions in the etching solution using a chelate resin, and sulfuric acid when the copper ions in the etching solution measured by the copper ion concentration measuring means are at or above a predetermined concentration. An etching solution regenerator that regenerates the copper ion removing means by using a metal. When the copper ions in the etching solution from which the copper ions have been removed by the copper ion removing unit are equal to or higher than a preset concentration, the etching solution is stopped from flowing into the copper ion removing unit, and water is removed from the copper ions. 2. An etching solution regenerating apparatus according to claim 1, wherein the solution flowing into the means and the solution discharged from the copper ion removing means after flowing in is discarded or mixed with the etching solution. When the copper ion concentration of the solution flowing into the sulfuric acid and discharged from the copper ion removing unit is equal to or lower than a preset concentration, the sulfuric acid is stopped flowing into the copper ion removing unit, and water is removed from the copper ion. The etching solution regenerating apparatus according to claim 1, wherein the solution flowing into the removing means and the solution discharged from the copper ion removing means after flowing in are mixed with sulfuric acid containing discarded or regenerated copper ions. 2. The etching according to claim 1, further comprising: a copper recovery unit that recovers the copper ion from the sulfuric acid containing copper ions discharged from the copper ion removal unit in order to regenerate the copper ion removal unit. Liquid regenerator. In a regeneration method for regenerating the etching solution when a copper etching solution containing at least copper ions, sulfate ions, hydrogen peroxide, one or more acids and copper ions have a concentration higher than a preset concentration, The copper ion concentration measuring step to be measured, the copper ion removing step of removing copper ions in the etching solution using a chelate resin, and the chelate from which copper ions have been removed in the copper ion removing step using sulfuric acid as a regenerating solution An etching solution regeneration method comprising a regeneration step of regenerating a resin. 6. The etching solution regeneration method according to claim 5, wherein a washing step of washing the chelate resin from which the copper ions have been removed with water instead of the etching solution is performed before the regeneration step. A water washing step of washing the chelated resin regenerated using water instead of sulfuric acid after the regeneration step, and mixing the solution discharged from the water washing step with sulfuric acid containing copper ions after disposal or regeneration. 5. The method for regenerating an etching solution according to 5. 6. The etching solution regeneration method according to claim 5, wherein a copper recovery step of recovering metallic copper from sulfuric acid containing copper ions discharged from the regeneration step is performed. Adjust the flow rate in the flow rate setting step, which sets the flow rate of the etchant when the copper ion measured in the copper ion measurement step is higher than the preset concentration, and flows in two or more flow paths according to the concentration. One channel is flowed to the mixing step, one channel is flowed to the copper ion removal step by the chelate resin tower using the chelate resin, and the etching solution from which the copper ions have been removed is flowed to the mixing step, Is mixed with an etching solution that has not been removed, and a copper ion concentration measurement step is provided downstream of the copper ion removal step so that the copper ion concentration of the etching solution discharged from the copper ion removal step exceeds a preset concentration. When the flow rate is set, the flow rate setting step stops flowing into the etching solution for the copper ion removal step, and water is flowed into the chelate resin tower from another flow path, and the chelate resin is washed with water. A washing step and a copper ion concentration measuring step for measuring the copper ion concentration of the solution discharged from the chelate resin tower at the time of washing and a waste liquid step for discarding the solution are provided, and the concentration of the copper ion concentration is set in advance. When the above is reached, stop the inflow of water, let sulfuric acid flow into the chelate resin tower from another flow path, and regenerate the chelate resin, and the solution discharged from the chelate resin tower at the time of regeneration When a copper ion concentration measuring step for measuring the copper ion concentration and a copper recovery step for recovering metal copper from the solution are provided, and when the copper ion concentration discharged from the chelate resin tower is equal to or lower than a preset concentration 6. The method of regenerating an etching solution according to claim 5, wherein the inflow of sulfuric acid is stopped and the first etching solution having a predetermined copper ion concentration is allowed to flow, and the above steps are repeated.

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