If the copper surface is not thoroughly cleaned, the metallization will be affected as follows:
1: The metal plating layer is peeled off from the object to be plated
2: The uneven metal coating and uneven gloss affect the appearance
3: The metallization of the plated material does not completely affect the quality
Therefore, only cleaning before metallization can obtain good electroplating effect.
The electroplating equipment and environment of the circuit board are not operated in a clean room, and external pollution such as dust in the external environment and fingerprints of operators is inevitable. However, these external factors are fatal damage to the quality of electroplating. After the circuit board is drilled, there will be bristles and powder residue on the board surface. Therefore, planning will be done before the deslagging process. The circuit board is physically cleaned using a brushing process, so that the copper surface can have a clean surface before it evolves into chemical copper.
The surface treatment before electroless copper plating is a chemical cleaning method. First, two processes of degreasing and pickling are carried out. The degreasing treatment adopts different methods such as organic solvents, water-soluble degreasing agents, and electrolytic degreasing. For environmental reasons, most industries currently use water-soluble and semi-water-soluble chemical solutions. The function of pickling is to remove oxides on the metal surface, exposing the fresh copper surface, and forming a good electroplating effect.
In terms of the acidic cleaning agents used, inorganic acids such as sulfuric acid and hydrochloric acid are the main ones. Part of the process planning is to avoid the influence of uneven oxidation of incoming circuit boards, and the micro-etching process is planned to do slight surface corrosion. It is desirable to use a larger amount of etch to remove the copper surface to a consistent level to ensure freshness of the plated surface. The commonly used micro-etching systems are: sodium persulfate, sulfuric acid hydrogen peroxide, etc. After micro-etching, pickling, water washing and other processes can be used to enter the metallization process.