KR101545245B1 - Device for regeneration of etchant and copper recovery using rgb color sensor and orp sensor - Google Patents

Abstract

The etching solution regeneration and copper recovery apparatus using the algebra color sensor and the arsenic sensor according to the present invention is an etching solution regeneration and copper recovery apparatus for regenerating an etching solution containing copper by electrolysis and recovering copper, A regeneration tank for regenerating the waste etchant generated in the etch tank; a recovery tank for recovering copper deposited in the regeneration tank; and a control unit for controlling the etching tank, the regeneration tank and the recovery tank, The regeneration tank may include an alibi color sensor and an ORP sensor.
According to the present invention, as the etching proceeds in the etching bath, the aged etching solution is transported to the regeneration bath and is regenerated in an electrolytic manner in real time, thereby preventing the generation of the waste etching solution.
In addition, by collecting copper in real time simultaneously with the progress of the etching process, there is no downtime for stopping the etching process or performing a separate operation, thereby increasing the operating rate of the etching process and increasing the productivity of copper.
Further, by adjusting the copper concentration of the anode actual liquid through the color information of the anode actual fluid contained in the cathode chamber, optimal copper recovery efficiency can be realized.

Description

TECHNICAL FIELD [0001] The present invention relates to an etching solution regeneration and copper recovery device using an alibi color sensor and an alkaline sensor,

More particularly, the present invention relates to a method and apparatus for regenerating a ferric chloride solution and recovering copper from the etchant by transferring a spent etchant aging as the etching progresses in an etch bath to a regeneration bath and real- And the copper concentration in the cathode chamber of the electrolysis tank is controlled constantly by using the color sensor and the ORP sensor in order to automatically separate and collect the copper mixed with the cathode solution of the poisonous concentrated hydrochloric acid, Recovering the iron chloride solution and recovering the copper chloride.

Etching is performed in the circuit formation of electronic parts and precision parts such as PCB (Printed Circuit Board), TAB (Tape Automated Bonding), BGA (Ball Grid Array), COF (Chip On Flexible Printed Circuit) , And copper and copper alloys are selectively removed, leaving only the circuit.

Generally, in the etching mechanism, the etching solution first oxidizes the surfaces of the copper and the copper alloy to become a metal oxide, and the process of dissolving the metal oxide is repeated.

The waste etchant generated by such an etching process is toxic, and various methods such as chemical dilution, precipitation, and substitution of a waste etchant are used in order to treat the waste.

However, the use of a large amount of neutralizing agent and oxidizing reducing agent to treat the waste etchant causes secondary pollutants, and there is a problem that the sludge produced by chemical treatment must be treated again.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide a method and apparatus for transferring waste etchant aging as etching progresses in an etching bath to a regeneration bath, And to provide an etching liquid regeneration and copper recovery apparatus that prevents an etching liquid from being generated.

It is a further object of the present invention to provide a method for automatically separating and recovering copper mixed with a catholyte solution of poisonous concentrated hydrochloric acid by uniformly controlling the copper concentration in the electrolysis bath cathode compartment by using an unknown color sensor and an ORP sensor And to provide an etchant regeneration and copper recovery apparatus that can reliably and efficiently recover copper.

It is still another object of the present invention to provide a copper plating method and a copper plating method which can recover copper in real time at the same time as the etching process is carried out so that the etching process can be stopped or downtime for performing a separate operation can be eliminated to increase the operating rate of the etching process, And an apparatus for recovering an etchant and recovering copper.

It is still another object of the present invention to provide an etching liquid regeneration and copper recovery apparatus capable of realizing optimal copper recovery efficiency by controlling the copper concentration of the anode actual liquid through the color information of the anode actual fluid contained in the cathode chamber.

In order to accomplish the above object, there is provided an etching solution regeneration and copper recovery apparatus using an algae color sensor and an alkaline sensor according to the present invention for regenerating an etching solution containing copper by electrolysis and regenerating an etching solution for recovering copper, A regeneration tank for regenerating a waste etchant generated in the etch tank; a recovery tank for recovering copper precipitated in the regeneration tank; and a regeneration tank for regulating the etchant, the regeneration tank and the recovery tank, And the regeneration tank includes an alibi color sensor and an ORP sensor.

Preferably, the regeneration tank includes a cathode chamber including a cathode electrode to which a predetermined power source is applied, an anode chamber to which the waste etchant is fed, and a cathode electrode to which a predetermined power source is applied, And an ion exchange membrane disposed between the positive and negative electrodes, wherein the positive electrode and the negative electrode are disposed opposite to each other.

The regeneration bath may further include a scraper for scraping copper precipitated in crystals into the cathode electrode by electrolysis and ion exchange of the anode chamber and the cathode chamber.

Here, the scraper may be installed on both sides of the cathode electrode.

Preferably, the cathode electrode comprises either graphite or a titanium component.

Further, the ion exchange membrane may be provided as a porous polytetrafluoroethylene nonwoven fabric.

The anode electrode may be formed in a mesh shape.

Preferably, a conveying screw for conveying a negative electrode actual liquid containing precipitated copper to the recovery tank is disposed below the cathode chamber.

The regeneration bath may include a negative electrode fluid circulation tank for supplying the negative electrode fluid into the negative electrode chamber.

Preferably, the regeneration tank may include a cathode chamber provided on both sides of the cathode chamber and a cathode chamber provided in a "spiral" shape, and a cathode fluid circulation tank disposed below the cathode chamber.

In addition, the recovery tank may include a transfer hopper for transferring the negative electrode actual liquid containing copper from the cathode chamber, and a recovery basket for receiving the negative electrode actual liquid supplied from the transfer hopper.

Further, the recovery basket may include a filter member for separating copper from the anode solution containing copper.

Preferably, the bottom of the recovery basket is filled with the anode actual fluid having passed through the filter member and the copper is separated, and the cathode actual fluid separated from the copper is transferred to the anode fluid returning bath through the cathode fluid returning line.

Meanwhile, the etchant circulation line is provided in the etching tank and the anode chamber, the waste etchant generated in the etchant through the etchant circulation line is transferred to the anode chamber, and the etchant recovered through electrolysis in the anode chamber is transferred to the etchant Can be transported to the bath.

In addition, the cathode chamber may include a cathode fluid circulation line for circulating the cathode actual fluid accommodated in the lower portion of the cathode chamber to the upper portion of the cathode chamber.

Preferably, a cooler for controlling the temperature of the negative electrode actual fluid to be circulated is installed in the negative electrode fluid inlet circulation line.

Here, the cooler may maintain the temperature of the circulating anode fluid at 40 ° C to 50 ° C.

In addition, the alibi color sensor and the alkaline sensor may be installed in the anode real liquid circulation line.

Preferably, the algebraic color sensor senses red color information (RValue) of a circulating anode real liquid, and the algebraic color sensor detects color information of the cathode actual liquid in a range of 0 (black) to 999 (white) A red, green, and blue combination of red color information (R value), and when the red color information (R value) is out of the range of 400 to 500, an abnormal detection signal is transmitted to the control unit.

According to the present invention, as the etching proceeds in the etching bath, the aged etching solution is transported to the regeneration bath and is regenerated in an electrolytic manner in real time, thereby preventing the generation of the waste etching solution.

In addition, it is possible to automatically separate and recover the copper mixed with the anode actual solution of the poisonous concentrated hydrochloric acid, and then extract the hydrochloric acid liquid by the pressing method to recover the copper in a lump form, thereby protecting the operator from the poisonous environment.

In addition, by collecting copper in real time simultaneously with the progress of the etching process, there is no downtime for stopping the etching process or performing a separate operation, thereby increasing the operating rate of the etching process and increasing the productivity of copper.

Further, by adjusting the copper concentration of the anode actual liquid through the color information of the anode actual fluid contained in the cathode chamber, optimal copper recovery efficiency can be realized.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
1 is a schematic view of an etching liquid regeneration and copper recovery apparatus according to the present invention,
2 is a configuration diagram of the etching solution regeneration and copper recovery apparatus according to the present invention.

Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings.

Prior to this, the terms used in the specification and claims should not be construed in a dictionary sense, and the inventor may, on the principle that the concept of a term can be properly defined in order to explain its invention in the best way And should be construed in light of the meanings and concepts consistent with the technical idea of the present invention.

Therefore, the embodiments shown in the present specification and the drawings are only exemplary embodiments of the present invention, and not all of the technical ideas of the present invention are presented. Therefore, various equivalents It should be understood that water and variations may exist.

FIG. 1 is a schematic view of an etching liquid regeneration apparatus and a copper recovery apparatus according to the present invention, and FIG. 2 is a configuration diagram of an etching liquid regeneration apparatus and a copper recovery apparatus according to the present invention.

1 and 2, an etching solution regeneration and copper recovery apparatus according to the present invention is an etching solution regeneration and copper recovery apparatus for regenerating an etching solution containing copper by electrolysis and recovering copper, wherein an etching process is performed (10); A regeneration tank 20 for regenerating the waste etchant generated in the etching tank 10; A recovery tank (30) for recovering copper deposited in the regeneration tank (20); And a control unit 40 for controlling the etching tank 10, the regeneration tank 20 and the recovery tank 30. The regeneration tank 20 includes an alibi color sensor 72 for sensing the color of the received etchant, And an arpeggiator 73. [0033]

That is, the etching solution regeneration and copper recovery apparatus according to the present invention mainly comprises an etching tank 10, a regeneration tank 20, a recovery tank 30, and a control unit 40, The anode chamber 22 and the cathode chamber 24 are disposed to receive the waste etching solution transferred from the etching bath 10 by piping connection with the etching bath 10.

The waste etchant may be acidic iron chloride, and the main material of the apparatus frame, particularly, the apparatus forming the frame to be in contact with the solution may be composed of a chemical resistant synthetic resin such as PVC, PP, or PVDF , Preferably HT-PVC material in consideration of workability and heat stability.

First, when a PCB substrate is put in an etching solution containing a ferric chloride solution in an etching bath, copper is oxidized to divalent copper and trivalent iron is reduced to divalent iron.

Further, in the anode chamber, the bivalent iron is oxidized to trivalent iron, and in the cathode chamber, the bivalent copper is reduced and the trivalent iron is reduced to the bivalent iron.

The regeneration tank 20 includes an anode chamber 22 to which predetermined power is applied and an anode chamber 22 to which the waste etchant is transferred and a cathode electrode A cathode chamber 24 including an anode chamber 23 and an ion exchange membrane 25 disposed between the anode chamber 22 and the cathode chamber 24.

Also, as shown in FIGS. 1 and 2, the anode electrode 21 and the cathode electrode 23 are disposed to be opposed to each other, so that ion exchange according to electrolysis can be performed.

Here, the negative electrode 23 tends to become more corrosive to hydrochloric acid and chloride, so nickel or iron is generally unsuitable and carbon is less likely to corrode, but copper precipitation can occur in the pores of the carbon surface, It is preferable to use non-porous graphite having good conductivity when carbon is used. More preferably, the cathode electrode 23 is made of graphite or a titanium component. do.

The anode electrode 21 is preferably a metal electrode resistant to an aqueous solution of hydrochloric acid, and an insoluble DSA (Dimensionally Stable Anode) electrode coated with ruthenium oxide or iridium oxide on a titanium surface is used, So that rapid cyclic contact of the etchant can be achieved.

Here, although the current flows through the ion exchange membrane 25, it should be provided so as to completely block the liquid mixing between the anode chamber 22 and the cathode chamber 24, and may be provided as a porous polytetrafluoroethylene nonwoven fabric .

On the other hand, the regeneration tank 20 is provided with a scraper 26 for scraping copper precipitated in crystals into the cathode electrode 23 by electrolysis and ion exchange between the anode chamber 22 and the cathode chamber 24 May be included.

The regeneration tank 20 may further include a negative electrode fluid circulation tank 28 for supplying negative electrode fluid to the negative electrode chamber 24.

2, the regeneration tank 20 includes a cathode chamber 24 provided in a shape of "ㅗ", an anode chamber 22 disposed on both sides of the cathode chamber 24, and a cathode chamber 24 disposed on both sides of the cathode chamber 24, And a negative electrode actual fluid circulation tank 28 disposed at a lower portion thereof.

In this case, since the cathode electrode 23 is ion-exchanged with the anode electrode 21 disposed on both sides, the scraper 26 for scraping off copper precipitated on the cathode electrode 23 is electrically connected to the cathode electrode 21, (Not shown).

Here, a conveying screw 27 for conveying a negative electrode actual liquid containing precipitated copper to the collection tank 30 may be disposed below the cathode chamber 24.

The recovery tank 30 is provided with a transfer hopper 32 for transferring a negative electrode actual fluid containing copper from the cathode chamber 24 and a recovery basket 34 for receiving the negative electrode actual liquid supplied from the transfer hopper 32 ).

In addition, the recovery basket 34 may further include a filter member 35 for separating copper from the anode solution containing copper, and the filter member 35 may be passed through the lower portion of the recovery basket 34 And the anode actual fluid from which the copper is separated may be transferred to the anode real fluid circulating tank 28 through the cathode actual fluid collecting line 50. [

2, a cathode chamber 24 provided in a substantially "ㅗ" shape in the center is disposed, two ion exchange membranes 25 are provided on both sides of the protruded cathode chamber 24, The anode chamber 22 is disposed on the side of the exchange membrane 25 and the anode fluid circulation tank 28 is disposed below the cathode chamber 24 to provide the regeneration tank 20.

Here, the cathode chamber 24 and the cathode fluid outlet circulation vessel 28 may be configured to be circulated at all times, and the liquid level may be maintained at the upper overflow height of the cathode chamber 24.

The scraper 26 is disposed at a close distance from the cathode 23 so as to scrape off copper deposited on the cathode 23 and control the setting of the scraping cycle according to the current density.

The scraper 26 is made of PTFE or its coating material which is electrically non-conductive and satisfies the requirements of chemical resistance and heat resistance. The scraper 26 is connected to a cylinder that performs reciprocating movement under control of the control unit 40, have.

The scraped copper is deposited on the lower portion of the cathode chamber 24 by the driving of the scraper 26 and is collected in the transport hopper 32 as the transporting screw 27 is driven.

Here, the feed screw 27 is driven by the control unit 40 under the control of the PVDF material, and is preferably controlled to rotate at 20 to 100 RPM.

A valve V is installed at an end of the transfer hopper 32. The valve V is automatically opened and closed in accordance with the time set by the control unit 40 to discharge the anode actual liquid containing copper .

Here, the discharged negative electrode actual liquid containing copper is accommodated in the recovering basket 34, and the negative electrode actual liquid containing copper by the filter member 35 provided in the recovering basket 34 is supplied to the positive electrode Separated.

Here, the filter member 35 may be formed of a filter net having a mesh size of 10 to 100 (탆) of polypropylene.

That is, the precipitated copper is collected on the filter member 35 and the catholyte solution is collected into the lower part of the recovery basket 34. The collected catholyte is supplied to the pump P Liquid is circulated through the venturi 29 provided in the cathode actual fluid collection line 50 to the anode fluid circulation tank 28 and the cathode liquid is supplied to the cathode chamber through the pump P provided in the anode fluid circulation tank 28. [ (24).

Thereafter, as the copper is accumulated in the filter member 35 of the recovery basket 34, the recovery basket 34 is replaced and the accumulated copper is further compressed to further separate the filtrate (water content less than 50%), And is recovered in a lump form.

The etchant circulation line 60 is provided in the etching tank 10 and the anode chamber 22 and the waste etchant generated in the etching tank 10 through the etchant circulation line 60 flows into the anode chamber 22, and the etchant recovered through electrolysis in the anode chamber 22 may be circulated to the etch bath 10.

2, the cathode chamber 24 further includes a cathode fluid circulation line 70 for circulating the cathode actual fluid accommodated in the lower portion of the cathode chamber 24 to the upper portion of the cathode chamber 24 .

In this case, a cooler 74 for controlling the temperature of the negative electrode fluid to be circulated may be installed in the negative electrode fluid inlet circulation line 70, and the cooler 74 may control the temperature of the circulating negative electrode fluid to 40 ° C to 50 ° C As shown in Fig.

When the temperature of the negative electrode liquid is less than 40 ° C, there is a problem that the electrolyte reaction of the negative electrode 23 is lowered and the recovery efficiency of copper is lowered. When the temperature of the negative electrode liquid exceeds 50 ° C, There is a problem in that the PVC frame constituting the frame of the frame 24 can not be stably supported.

The alibi color sensor 72 and the ORP sensor 73 sense the color information of the anode actual liquid and the strength (potential) of the redox force to determine the etching solution regeneration and copper recovery device As a component for optimizing the copper recovery rate, it may preferably be installed in the negative electrode liquid-pumped circulation line 70 as shown in FIG.

In this case, the density of the resin crystals of the precipitated copper is relatively low, so that the copper tends to float in the actual solution of the negative electrode. In this case, the optimum copper recovery rate in the actual positive copper recovery is in the range of 8 to 12 g / There is a problem in that it is not applied to the automatic copper recovery apparatus of the present invention because the raped copper does not deposit smoothly.

Therefore, it is necessary to increase the current density of the cathode electrode 23 so as to be applicable to the automatic copper recovery apparatus, and to increase the copper concentration in the anode actual liquid to make the density of the precipitated copper to be more than a certain level, have.

As described above, the optimum copper recovery rate calculated by deducing the density of copper at a high density is a copper concentration of 13 g / L to 17 g / L in the cathode actual solution, and the range of the copper concentration is the R value Value) is in the range of 400 to 500.

When the R value is less than 400, the copper concentration of the anode actual solution is too high to lower the copper recovery rate due to re-dissolution. When the R value exceeds 500, the copper concentration of the anode actual solution becomes relatively low, Is not easy to settle.

On the other hand, the waste iron chloride etchant contains the ferric chloride and the ferric chloride ions in addition to the copper, unlike the purged copper chloride etching solution. They have different colors in darkness and have a color (red) other than the color Therefore, it is necessary to set additional control variables as a measure of the concentration change between the iron ions 2 and the iron ions 3 because the color sensor does not easily control the real solution of the negative electrode due to the change in color upon the reduction of iron chloride ions by electrolysis .

The ORP value of the catholyte solution, which depends on the ratio of Fe2 + and Fe3 + ions, depends on the copper recovery rate and should be properly controlled.

Here, the ORP value in the cathode chamber is preferably controlled in the range of 300 to 600 mV.

Therefore, the copper recovery apparatus according to the present invention includes the alibi color sensor 72 and the arsenic sensor 73 to sense the R value and the ORP value of the anode actual liquid and perform control according to the situation, May be stably provided so as to maintain the copper concentration and the bivalent iron ion concentration.

Here, the algebraic color sensor 72 is configured to detect the color information of the anode real liquid separately in a range of 0 (black) to 999 (white) by a combination of red, green, and blue.

When the red color information (R value) is out of the range of 400 to 500 or the off-peak value is out of the range of 300 to 600 mV, the alibi color sensor (72) and the arpeggiator (73) 40 as shown in FIG.

When the abnormality detection signal is received from the algebraic sensor 72 and the arsenic sensor 73, the control unit 40 automatically determines whether the negative electrode actual liquid is replenished in the negative electrode real liquid circulation tank 28 The control signal is transmitted to adjust the red color information and the opalescence value of the actual cathode liquid to be in the above range, thereby stably managing the copper concentration of the cathode actual liquid.

While the present invention has been described with reference to the exemplary embodiments and the drawings, it is to be understood that the technical scope of the present invention is not limited to these embodiments and that various changes and modifications will be apparent to those skilled in the art. Various modifications and variations may be made without departing from the scope of the appended claims.

10: etching tank 20: regeneration tank
21: anode electrode 22: anode chamber
23: cathode electrode 24: cathode chamber
25: ion exchange membrane 26: scraper
27: Feed screw 28: Cathode real fluid circulation tank
29: Venturi 30: Recovery tank
32: Feed hopper 34: Return basket
35: filter member 40:
50: cathode actual fluid collection line 60: etchant circulation line
70: cathode real fluid circulation line 72: algae color sensor
73: Ophthalmic sensor 74: Cooler
P: Pump V: Valve

Claims (20)

An etching solution regeneration and copper recovery apparatus for regenerating an etching solution containing copper by electrolysis and recovering copper,
An etching bath on which an etching process is performed;
A regeneration tank for regenerating a waste etchant generated in the etching bath;
A recovery tank for recovering copper precipitated in the regeneration tank;
And a control unit for controlling the etching bath, the regeneration bath and the recovery bath,
The regeneration tank includes an alibi color sensor and an ORP sensor,
Wherein,
An anode chamber including an anode electrode to which a predetermined power source is applied, the anode chamber being fed with the waste etchant;
A cathode chamber including a cathode electrode to which a predetermined predetermined power source is applied;
An ion exchange membrane disposed between the anode chamber and the cathode chamber;
And a scraper for scraping copper precipitated on the cathode electrode by electrolysis and ion exchange of the anode chamber and the cathode chamber,
Wherein the anode electrode and the cathode electrode are disposed opposite to each other. The etching solution regeneration and copper recovery apparatus using the algae color sensor and the alkaline sensor. The method according to claim 1,
And the scraper is installed on both sides of the cathode electrode. The etching solution regeneration and copper recovery apparatus using the algae color sensor and the alkaline sensor. The method according to claim 1,
Wherein the cathode electrode comprises either graphite or a titanium component, and an etching liquid regeneration and copper recovery apparatus using the algae color sensor and the alkaline sensor. The method according to claim 1,
Wherein the ion exchange membrane is provided as a porous polytetrafluoroethylene nonwoven fabric. The method according to claim 1,
Wherein the anode electrode is formed in a mesh shape, and the etchant regeneration and copper recovery apparatus using the algae color sensor and the aperture sensor. The method according to claim 1,
And a transfer screw for transferring a negative electrode actual liquid containing precipitated copper to the recovery tank is disposed in the lower portion of the cathode chamber. The method according to claim 1,
Wherein the regeneration bath further comprises a negative electrode fluid circulation tank for supplying the negative electrode fluid to the negative electrode chamber. 8. The method of claim 7,
Wherein the regeneration bath comprises an anode chamber arranged on both sides of a cathode chamber and a cathode chamber provided in a "spiral" shape, and a cathode fluid circulating vessel arranged below the cathode chamber, Regeneration and copper recovery device. 9. The method of claim 8,
The recovery tank,
A transfer hopper for transferring a negative electrode actual liquid containing copper from the negative electrode chamber;
And a recovery basket for receiving the negative electrode actual liquid supplied from the transfer hopper. The apparatus for regenerating and recovering the etching solution using the algae color sensor and the aperture sensor. 10. The method of claim 9,
Wherein the recovery basket further comprises a filter member for separating copper out of the anode effluent containing copper. 11. The method of claim 10,
Wherein the negative electrode fluid is separated from the bottom of the recovery basket through the filter member and copper is separated from the bottom of the recovery basket, and the negative electrode actual fluid separated from the copper is transferred to the negative electrode actual fluid circulation tank through the negative electrode actual fluid collection line. Etching solution regeneration and copper recovery device using sensor and ophthalmic sensor. The method according to claim 1,
Wherein an etchant circulating line is provided in the etching tank and the anode chamber, and a waste etchant generated in the etching tank is transferred to the anode chamber through the etchant circulating line, and the etchant recovered through electrolysis in the anode chamber is transferred to the etching tank And an etching liquid regeneration and copper recovery device using an alabi color sensor and an alkaline sensor. 13. The method of claim 12,
Wherein the cathode chamber further comprises a cathode real fluid circulation line for circulating a cathode actual fluid accommodated in a lower portion of the cathode chamber to an upper portion of the cathode chamber. 14. The method of claim 13,
And a cooler for controlling the temperature of the negative electrode actual liquid circulated is installed in the negative electrode actual liquid circulation line, and an etching liquid regeneration and copper recovery device using the algae color sensor and the alkaline sensor. 15. The method of claim 14,
Wherein the cooler maintains the temperature of the circulating anode liquid at 40 ° C to 50 ° C, and an etching liquid regeneration and copper recovery apparatus using the algae color sensor and the alkaline sensor. 16. The method of claim 15,
Wherein the RGB color sensor and the arithmetic sensor are installed in the anode real fluid circulation line. 17. The method of claim 16,
Wherein the RGB color sensor senses the red color information (R Value) of the circulating anode real liquid. 18. The method of claim 17,
The aliasing color sensor is configured to detect the color information of the anode real liquid separately by a combination of red, green and blue in a range of 0 (black) to 999 (white), and when the red color information R value is 400 Wherein the controller sends an abnormality detection signal to the control unit when the temperature of the etching solution is out of the range of about 500 to about 500. delete delete

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