Chemical copper plating pretreatment process for printed wiring board

Abstract

The invention discloses a chemical copper plating pretreatment process for a printed wiring board. The process comprises the following steps that 1, the printed wiring board is drilled at first and burrs at a drilled hole are removed; 2, the printed wiring board is put into a swelling agent aqueous solution to be soaked for 3-10 minutes; 3, the printed wiring board is put into a potassium permanganate strong alkali solution to be soaked for 5-25 minutes; 4, the printed wiring board is put into an aqueous solution of a reducing agent and a complexing agent to be soaked for 1-10 minutes; 5, the printed wiring board is put into an alkali oil removing solution with the concentration of 0.1-100 ml / L and containing polymer cationic surface active agents to be soaked for 5 minutes; 6, a microetching solution containing sulfuric acid and oxidizing agents is used for microetching, and bite etching is conducted under the acid condition; 7, the printed wiring board obtained after microetching enters a pre-dip solution; 8, the printed wiring board is transferred to 45-DEG C active fluid containing colloidal palladium to be soaked for 5 minutes from the pre-dip solution; and 9, the activated printed wiring board is subjected to dispergation through acid or alkaline or oxidized accelerating fluid with the concentration of 0.001-5 mol / L.

Description

technical field [0001] The invention relates to the field of surface treatment of printed circuit boards, in particular to the pretreatment process of electroless copper plating for through holes of printed circuit boards, the pretreatment process for electroless copper plating of printed circuit boards for obtaining coatings with good bonding force with substrates and its application. Background technique [0002] During the drilling of the via hole of the printed circuit board, a large amount of heat is generated due to the friction between the drill bit and the hole wall substrate while the drill rotates at high speed, so that the resin cut by the drill bit melts and adheres to the hole wall of the via hole, in order to ensure the subsequent metallization process. The electrical conductivity between the metal of the printed circuit board and the inner layer of the printed circuit board and the bonding force with the hole wall need to thoroughly clean the above-mentioned r...

AI Technical Summary

Problems solved by technology

[0003] For multi-layer printed circuit boards with more than two layers, if the residual glue residue in the via hole (drilling hole) is not cleaned cleanly, it will cause poor connection, or even electrical interconnection problems such as open circuit in the inner layer

In addition, when the glue is removed excessively on the via hole, a very rough hole wall will be produced, and the "wick" effect will be obvious. In severe cases, the copper layer on the hole wall will be rough, and a "copper tumor" will be generated that will affect the subsequent assembly of electronic components and electrical conduction.