SU773063A1 - Solution for removing tin-lead plating from copper base - Google Patents

Description

one

FIELD: technology. chemical processing of metals and is intended for use in electroplating and the production of printed circuit boards.

A known solution for removing lead-bearing coatings containing hydrofluoric acid and hydrogen peroxide 1.

This solution allows you to remove 10 Å lead-lead coatings at high speed (3-6 µm / min), however, causes intense etching of the substrate surface and the formation of a sludge film.

The closest to the above is a solution for removing tin-lead coatings containing bortochloric acid, copper boron fluoride in an amount of 2-50 g / l 20 (in terms of metal), ferrofluoric iron and water (2,

This solution also causes etching of the substrate surface.

The purpose of the invention is to prevent 25 etching of the substrate surface.

This goal is achieved in that a solution containing acid, copper boron and water is added. as acid nitric acid, 30

2

as well as non-ionic detergent in the following ratio of components, g / l:

Nitric acid 350-450

Boron fluoride copper

in terms of

metal0,5-1,0

Non-ionic detergent

substance1-10

Water up to 1 l

while as a non-ionic substance, the solution contains polyethylene glycol ethers of higher fatty alcohols and polyethylene glycol ethers of alkylphenols.

The nitric acid contained in the solution provides a high removal rate of the coating (2.5-5 µm / min), as it is a strong oxidizing agent and forms soluble compounds with lead and tin. Acid content above 450 g / l causes etching of the base; below 350 g / l reduces the rate of removal of the coating. The boron fluoride performs a double function. Copper ions accelerate the dissolution of the tin-lead coating due to the contact release of copper on it. However, the copper content is above 1 g / l.

Claims (2)

Claim 1, A solution for removing tin-lead coatings from a copper base, containing acid, copper boron fluoride and water, characterized in that, in order to prevent the surface of the base from being etched, as an acid, it loads parts into a bath with a solution at 15-30 ° C . Prepare several compositions of the solution, g / l: Nitric acid, 350 Copper boron fluoride per metal1 A mixture of polyethylene glycol esters of higher fatty alcohols (OS-20 preparation) 1 holds nitric acid ^ and additionally contains a nonionic detergent in the following ratio of components, g / l: Nitric acid Borofluoride copper in terms of metal Nonionic ^: detergent 350-450 0.5-1.0 Nitric Acid 400 Copper boron fluoride per metal 0.5 A mixture of polyethylene glycol ethers of alkyl phenols with the number of hydroxyethyl groups 6-8 (preparation OP-7) 5 substance Water 2. A solution according to item n and a with the fact that 1.0-10.0 Up to 1 liter 1, I distinguish as a non45 ionic detergent it contains polyethylene glycol ethers Nitric acid 450 Borftoya: flock of copper in terms of metal 0.75 5 of higher fatty alcohols and polyethylene glycol ethers of alkyl phenols.