KR20080075148A - Recyclable etching solution - Google Patents

Abstract

The invention relates to an aqueous etching solution which is recyclable by reducing a copper concentration during operation, is used for copper etching, in particular for printed circuits and for producing copper articles and which generally comprises water, ammonium, copper carbonate and ammonium carbonate. The inventive etching solution also comprises bromoacetylbiphenyland the derivatives thereof in the form of an additional catalyst.

Description

Recyclable Etching Solution {RECYCLABLE ETCHING SOLUTION}

The present invention relates to a recyclable aqueous etching solution by reducing copper concentration. Such solutions are used for copper etching, especially in the printed circuit industry and the copper component industry. The solution generally consisted of ammonia, copper carbonate, ammonium carbonate and water.

Conventional solutions exist in many forms. So, this solution is particularly concerned with the etching of printed circuits. This acceleration of the etching process plays an important role in the manufacture of printed circuits. Fabrication of printed circuits requires an acceleration of copper recovery to equilibrate between the etched copper content and the recovered copper content. The stability of this process is an important factor for ensuring continuity in etching quality in order to obtain the same element.

In the method of manufacturing a printed circuit, the circuit image is masked with a silkscreen or by a photosensitive process to form a "resist image". The copper surface not covered by the mask is etched with a suitable etching solution.

In another manufacture of double-sided printed circuits, the metallized tracks and holes are protected by metal resists. The organic resist is stripped and the bare copper is etched by a suitable solution. In this way the metallized tracks and holes of conductance are protected by metal resists during the etching process which is operated with ammonia solution and a base of copper salt.

Disadvantages include limited etch rates, slow process recovery of etch solutions, and instability of chemical variables that directly affect production.

The present invention is based on the challenges of acceleration of etch rate, regeneration of used solutions, and reuse in etching processes with stability of chemical parameters.

In order to solve this problem, the etching solution includes bromoacetylbiphenyl and derivatives thereof as another catalyst.

The present invention has been found to accelerate this process because it supports the regeneration process of the etching solution used by bromoacetylbiphenyl as a catalyst. It also serves to suppress the interference of acceleration and to accelerate the recycling of copper.

In this way, bromoacetylbiphenyl is used as an accelerator and a cocatalyst in an amount of 5 to 200 mg / l of the etching solution, preferably in an amount of 70 mg / l.

Bromoacetyl-biphenyl, preferably 4-bromoacetyl-biphenyl C ₁₄ H ₁₁ BrO is in the reproduction in the reproducing process _{[Cu (NH 3) 2]} + in the complex _{[Cu (NH 3) 4]} ++ Supports oxidation to complexes. In this way, the regeneration process of the etching solution is accelerated. [Cu (NH ₃ ) ₂ ] ⁺ ions delay the etching process and increase copper recycling, which causes [Cu (NH ₃ ) ₂ ] ⁺ to oxidize to [Cu (NH ₃ ) ₄ ] ⁺⁺ in etching This is also because [Cu (NH ₃ ) ₂ ] ⁺ must be stabilized by stabilizers in the recycling process. The etching process follows the scheme below:

Cu + [Cu (NH ₃ ) ₄ ] ⁺⁺ → 2 [Cu (NH ₃ ) ₂ ] ⁺

The regenerated portion is carried out using NH ₄ ⁺ , NH ₃ and oxygen complexes by the reaction:

4 [Cu (NH ₃ ) ₄ ] ⁺⁺ + 4NH ₃ + 4NH ⁺ + O ₂ → 4 [Cu (NH ₃ ) ₄ ] ⁺⁺ + 2HO

The regeneration portion is carried out using a current by the reaction:

[Cu (NH ₃ ) ₂ ] ⁺ → ½Cu + ½ [Cu (NH ₃ ) ₄ ] ⁺⁺

_{[Cu (NH 3) 2]} + + e - → Cu + 2NH 3

_{[Cu (NH 3) 4]} ++ + 2e - → Cu + 4NH 3

Increasing the copper oxidation rate systematically restores the increase in etch rate during the process. Vanadium pentoxide or other vanadium compounds are used as catalysts to increase the etching rate.

In addition, the use of a catalyst comprising vanadium and a cocatalyst comprising acetylbiphenyl to increase the etching rate in the present invention increases the oxidation rate of the used etching solution and acts as a stabilizer to increase the recycle rate. Has been proven.

In this way, the regeneration rate as well as the etch rate of the used etch solution simultaneously increases the stability of the process and the increase in recycle rate.

A significant role in the manufacture of printed circuits or printed circuits is passed through etching equipment which serves to break the copper surface continuously or discontinuously.

The following solutions have been demonstrated to yield the best results:

Solution number 1 :

60 to 140 copper per liter, corresponding to 117 to 272 g of CuCO ₃ per liter,

62 to 156 g of carbonate per liter, corresponding to 100 to 250 g of (NH ₄ ) ₂ CO ₃ per liter,

0.4-0.8 L ammonia solution per 1 L,

0.4 to 0.6 L of water,

200-1500 mg vanadium pentoxide per liter

5-200 mg 4-bromoacetylbiphenyl per liter.

Solution number 2 :

100 g of copper per liter equal to 194 g of CuCO ₃ per liter,

109 g of carbonate per liter equal to 175 g of (NH ₄ ) ₂ CO ₃ per liter,

0.5 liter of ammonia solution per liter

0.5 L of water,

1,100 mg of vanadium pentoxide per liter

70 mg 4-bromoacetylbiphenyl per liter.

Claims (15)

As an electrolytically and chemically recyclable etching solution, particularly for copper etching in the copper parts industry and printed circuits, which are generally made up of water, ammonia, copper carbonate and ammonium carbonate, the etching solutions are bromoacetylbiphenyl as auxiliary catalysts and Etching solution comprising a derivative thereof. The etching solution of claim 1 wherein about 10-100 mg / l bromoacetylbiphenyl and derivatives thereof are added to the etching solution. The etching solution of claim 1 or 2, wherein the etching solution comprises about 40 mg / l bromoacetylbiphenyl. The etching solution according to any one of claims 1 to 3, wherein 4-bromoacetylbiphenyl C ₁₄ H ₁₁ BrO is used as a catalyst for the etching solution. 5. The etching solution according to claim 1, wherein the pH of the etching solution is about 7.8 to 9, in particular 8.2. 6. The etching solution according to any one of claims 1 to 5, wherein the etching solution contains 60 to 140 g / l Cu ions. The etching solution according to claim 1, wherein the etching solution comprises 117 to 272 g / l, in particular 194 g / l CuCO ₃ . 8. The composition of any one of the preceding claims comprising 62 to 156 g / l carbonate, in particular 109 g / l carbonate, corresponding to 100 to 250 g / l of (NH ₄ ) ₂ CO ₃ . An etching solution, characterized in that. 9. An etching solution according to any one of claims 1 to 8 comprising 0.3 to 0.6 l / l of 25% ammonia. 10. Etching solution according to any one of the preceding claims comprising 0.3 to 0.6 l / l of water. The etching solution according to any one of claims 1 to 10, comprising 200 to 1,500 mg / l of vanadium or other corresponding vanadium compound. The etching solution of claim 11 wherein the etching solution comprises about 1,100 mg / l vanadium pentoxide (V ₂ O ₅ ). The etching solution according to claim 1, wherein the etching solution comprises about 0.5 to 100 g / l, in particular 35 g / l, of nitrate. Etching solution according to any of the preceding claims, characterized in that it is vaporized with O ₂ or air continuously or discontinuously by selection. The etching solution according to claim 1, wherein the temperature of the etching solution is adjusted to 40 ° C. to 60 ° C., in particular 54 ° C. 16.