JP3597250B2 - Etching solution regeneration method and etching solution regeneration device - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to an etchant regenerating method and an etchant regenerating apparatus for regenerating an etchant having a changed composition by corroding a metal to a re-etchable composition.
[0002]
[Prior art]
When an etching solution is etched on a printed circuit board or the like on which a pattern resist is formed, the composition changes by reacting with the corroded metal. Since etching cannot be performed with an etching solution having a changed composition, a regeneration aid is added to the etching solution having a changed composition to regenerate the composition of the etching solution to an etchable composition. For example, in the case of etching iron, when an iron (III) chloride solution is used as an etching solution, the composition of the iron (III) chloride solution as an etching solution changes as follows by etching.
4FeCl ₃ + 2Fe → 6FeCl ₂
That is, the iron (III) chloride solution reacts with iron, which is an etched metal, to change its composition to an iron (II) chloride solution.
[0003]
Then, a regeneration aid is added to the etching solution having a changed composition in the iron (II) chloride solution to regenerate it into the iron (III) chloride solution. (1), (2) and (3) shown below are generally used as regeneration aids. Also, the reaction formulas of the regeneration aid and the iron (II) chloride solution are shown simultaneously.
[0004]
{Circle around (1)} When chlorine gas is used as a regeneration aid, it is regenerated into an iron (III) chloride solution by a reaction of 6FeCl ₂ + 3Cl ₂ → 6FeCl ₃ .
[0005]
{Circle around (2)} When sodium chlorate and hydrochloric acid are used as regeneration aids, the solution is regenerated to an iron (III) chloride solution by a reaction of 6FeCl ₂ + NaClO ₃ + 6HCl → 6FeCl ₃ + 3H ₂ O + NaCl.
[0006]
{Circle around (3)} When ozone and hydrochloric acid are used as a regeneration aid, the solution is regenerated to an iron (III) chloride solution by a reaction of 2FeCl ₂ + O ₃ + 2HCl → 2FeCl ₃ + H ₂ O + O ₂ ↑.
[0007]
In this way, the composition of the etching solution can be regenerated to the iron (III) chloride solution by adding the regeneration aid to the etching solution whose composition has changed to the iron (II) chloride solution. Of course, it is needless to say that etching can be performed again with the regenerated etching solution.
[0008]
[Problems to be solved by the invention]
However, chlorine gas used as a regeneration aid in the above method (1) is dangerous to human life if inhaled by humans, so safety equipment is required in case of accident. Was huge.
In addition, the method (2) has a problem that sodium chloride is generated as an impurity, and the sodium chlorate reacts with an organic substance and burns. ing.
Furthermore, in the method ( ₃₎ , the equipment for generating O ₃ is expensive, and the running cost of the power and the electrodes is also effective. Was.
[0009]
SUMMARY OF THE INVENTION An object of the present invention is to provide an etching solution regenerating method and an etching solution regenerating apparatus that do not require equipment costs for safety and have no danger, and that reduce the cost of regenerating the etching solution. .
[0010]
[Means for Solving the Problems]
The method of reproducing the etching solution of the invention, first by mixing a hydrogen peroxide solution of a predetermined amount of hydrochloric acid and the hydrochloric acid in the same amount or small amount in the mixer, the liquid mixture in the mixer performs the corrosion of metal It is characterized in that it is charged into a regeneration tank of an iron chloride etching solution having a changed composition.
[0011]
An etching solution regenerating apparatus according to the present invention comprises a first storage means for storing hydrochloric acid, a second storage means for storing hydrogen peroxide solution, and an iron chloride etching apparatus whose composition has been changed by corroding a metal from an etching machine. a regeneration tank where the liquid is discharged, first, after mixing the hydrogen peroxide solution of hydrochloric acid and the hydrochloric acid in the same amount or small amount being stored in the second storage means, the reproduction of this mixture A mixer to be added to the iron chloride etching solution in the tank.
[0014]
[Action]
In the reproducing method of the etching solution of the present invention, the regeneration tank that altered iron chloride etching solution having a composition by performing the corrosion of metal is discharged, the hydrochloric acid and the hydrogen peroxide solution of hydrochloric acid in the same amount or small amount Mixing is performed by a mixer, and a mixed liquid mixed by the mixer is supplied . That is, since hydrogen peroxide and hydrochloric acid are mixed into the iron chloride etching solution after being mixed, the hydrogen peroxide and the hydrochloric acid are charged, so that the decomposition of the hydrogen peroxide does not occur, and an explosion or the like occurs in the process of regenerating the etching solution. It is not. In addition, since the unit price of the hydrogen peroxide solution and hydrochloric acid is low, the cost for regenerating the etching solution is also low.
[0015]
Further, in the etching solution regenerating apparatus of the present invention, after the hydrochloric acid and the hydrogen peroxide solution are mixed at a predetermined mixing ratio from the first and second storage means in the mixer, the mixed solution is mixed with the iron chloride etching solution in the regenerating tank. Add. By adding this to the iron chloride etchant were mixed with hydrochloric acid and hydrogen peroxide can be rapid decomposition of hydrogen peroxide to the stable reaction does not occur.
[0017]
【Example】
FIG. 1 is a diagram showing a schematic configuration of an etching system to which a method for regenerating an etchant according to an embodiment of the present invention is applied. The etching system includes a tank 1 for storing a hydrogen peroxide solution, a tank 2 for storing a hydrochloric acid, a mixer 3 for mixing the hydrogen peroxide solution and the hydrochloric acid stored in the tank 1 and the tank 2, and an etching system. An etching machine 4 for performing etching and a regeneration tank 5 for regenerating an etchant used in the etching machine 4 and having a reduced etching ability due to a change in composition. In this embodiment, the etching solution is an iron (III) chloride solution, and the etching machine 4 etches iron. Since the tanks 1 and 2 store the hydrogen peroxide solution and the hydrochloric acid alone, the hydrogen peroxide and the hydrochloric acid are hardly separated in the tanks 1 and 2, so that the capacity of the tanks 1 and 2 can be increased and Hydrogen peroxide and hydrochloric acid can also be stored across. In this way, the number of operations for replenishing the tanks 1 and 2 with hydrogen peroxide solution and hydrochloric acid can be reduced.
[0018]
The composition of the iron (III) chloride solution used in the etching machine 4 changes as follows as iron is etched.
4FeCl ₃ + 2Fe → 6FeCl ₂
That is, the iron (III) chloride solution, which is an etching solution, changes into a iron (II) chloride solution by corroding iron. The etching machine 4 discharges the etching liquid having the composition changed as described above to the regeneration tank 5 using a pump (not shown).
[0019]
The hydrogen peroxide solution and the hydrochloric acid stored in the tank 1 and the tank 2 are respectively discharged to the mixer 3, and the hydrogen peroxide solution and the hydrochloric acid are mixed in the mixer 3. There is neither rapid decomposition of hydrogen peroxide nor reaction with hydrochloric acid in the mixer 3. In the mixed solution, HCl and H ₂ O ₂ are mixed at a ratio of HCl: H ₂ O ₂ = 2: 1. Note that this ratio is a ratio of the molar quantity of HCl and H ₂ O ₂ that is part of the solution in the mixer 3, not the ratio of the amount of solution to be introduced from the tank 1 and tank 2. Depending on the concentration of H ₂ O ₂ in the tank 1 and the concentration of HCl in the tank 2, the ratio of the amount of the solution to be charged is changed. Further, this solution contains HCl twice as much as H ₂ O _{2 in} molar amount, but it may be 2.5 times or 3 times as long as the amount is twice or more. That is, the molar amount of HCl may be at least twice the molar amount of H ₂ O ₂ . The reason for setting such a ratio will be described later.
[0020]
Then, a solution containing hydrogen peroxide and hydrochloric acid mixed in the mixer 3 is added to the regeneration tank 5. That is, hydrogen peroxide and hydrochloric acid are added simultaneously to the iron (II) chloride solution in the regenerating tank 5, and the iron (II) chloride, hydrogen peroxide, and hydrochloric acid start a reaction in the regenerating tank 5. I do. The reaction formula at this time is shown below.
2FeCl ₂ + H ₂ O ₂ + 2HCl → 2FeCl ₃ + 2H ₂ O
As is apparent from this chemical formula, the iron (II) chloride solution changes to an iron (III) chloride solution when a solution containing hydrogen peroxide and hydrochloric acid is added. The regeneration tank 5 is provided with an etching control device (for example, an etching control device described in the specification of Japanese Patent Application No. 7-48545) for detecting the concentration of the regenerated (III) iron chloride solution. This controls the amount of a solution containing hydrogen peroxide and hydrochloric acid to be charged from the mixer 3 so that the iron (III) chloride solution in the regeneration tank 5 has a predetermined concentration. Therefore, excessive HCl and H ₂ O ₂ are not charged into the regeneration tank 5. Further, since hydrogen peroxide and hydrochloric acid are simultaneously added to the iron (II) chloride solution, rapid decomposition of hydrogen peroxide in the regeneration tank 5 does not occur. Further, the reaction in the mixer 3 or the regeneration tank 5 can be further stabilized by introducing a negative catalyst (for example, urea) for reducing the reaction rate into the mixer 3 or the regeneration tank 5.
[0021]
Incidentally, the hydrogen peroxide previously regeneration tank 5 was added, followed in the case of a so addition of hydrochloric acid, resulting decomposition of rapid hydrogen peroxide when added to the chloride (II) iron solution of hydrogen peroxide, explosion However, in this embodiment, as described above, the hydrogen peroxide solution and the hydrochloric acid are once mixed in the mixer 3, and the mixed solution is added to the iron (II) chloride solution in the regeneration tank 5. There is no such danger .
[0022]
Wherein the molar amount of HCl is equal twice the molar amount of _H 2 _{O 2,} HCl and _H 2 _{O 2} is decomposed all in the regeneration step. Therefore, there is no generation of gas containing HCl and no adverse effect on the human body. If the molar amount of HCl is larger than twice the molar amount of H ₂ O ₂ , HCl will remain in the regenerated etching solution, but H ₂ O ₂ is completely decomposed in the regenerating step. Therefore, there is no danger of the above explosion. Incidentally, if less than 2 times the molar amount of the molar amount of HCl H ₂ O _2, H ₂ O ₂ remains in the etching solution which has been reproduced, resulting in danger of explosion. Etching is possible even if an iron (III) chloride solution containing HCl is used as an etching solution, and if such an etching solution is used, the peroxide may be used depending on the amount of HCl contained in the etching solution. simply by introducing hydrogen water, it is possible to reproduce the etchant.
[0023]
As described above, iron (III) chloride changes into iron (II) chloride in the etching step, and hydrogen peroxide and hydrochloric acid are added in the regeneration step to regenerate iron (II) chloride into iron (III) chloride. By the way, in the etching step, 4 mol of iron (III) chloride is changed to 6 mol of iron (II) chloride as described above. Further, in the regeneration step, 2 mol of iron (II) chloride is changed to 2 mol of iron (III) chloride. That is, by performing the etching step and the regeneration step, 4 mol of (III) iron chloride is converted to 6 mol of (III) iron chloride, whereby 1.5 times (III) iron chloride can be obtained. Thus, increased iron (III) chloride can be used in other etching systems. In addition, iron (III) chloride increased by regeneration can be used for other purposes. For example, hydrochloric acid and hydrofluoric acid are currently used in the steel washing process for polishing the surface of iron. However, the steel washing process can be performed by using the increased iron (III) chloride.
[0024]
In the above embodiment, the corroding metal is iron. However, the iron (III) chloride solution can also be used for etching by corroding metals such as nickel and chromium. In this case as well, the etching solution can be regenerated by adding the above-mentioned hydrogen peroxide and hydrochloric acid, but this regeneration does not increase iron (III) chloride.
[0025]
【The invention's effect】
As described above, according to the present invention, when the etching solution is regenerated, rapid decomposition of hydrogen peroxide does not occur, and there is no danger of explosion or the like. In addition, since there is no use or generation of harmful gases such as chlorine gas, equipment costs and the like are reduced, and the regeneration of the etching solution is performed using hydrogen peroxide and hydrochloric acid. be able to.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of an etching system to which an etching liquid regenerating method according to an embodiment of the present invention is applied.
[Explanation of symbols]
1, 2-tank 3-mixer 4-etching machine 5-regeneration tank

Claims (2)

First, a predetermined amount of hydrochloric acid and hydrogen peroxide in the hydrochloric acid in the same amount or small amount mixed in a mixer, reproduction of altered iron chloride etching solution having a composition the liquid mixture in the mixer performs the corrosion of metal A method for regenerating an etching solution, which comprises introducing the solution into a tank . First storage means for storing hydrochloric acid;
Second storage means for storing hydrogen peroxide water;
A regeneration tank from which the iron chloride etchant whose composition has changed by corroding the metal from the etching machine is discharged,
First, after mixing the hydrogen peroxide solution of hydrochloric acid and the hydrochloric acid in the same amount or small amount being stored in the second storage means, a mixer adding the mixture to the iron chloride etchant of the regeneration tank When,
An etching liquid regenerating apparatus comprising:

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