With the rapid development of pcb industry, PCB gradually towards the direction of high precision fine lines, small aperture, high aspect ratio (6:1-10:1), hole copper requirements of 20-25Um, of

which DF line distance ≤4MIl board, the general production of pcb companies have electroplating clip film problems. The following small series to say in detail about the causes of plating clip film in

the process of multi-layer pcb proofing and how to improve the treatment.

The cause of plating clip film in the process of multilayer pcb proofing

1. the plate graphic distribution is not uniform, isolated several lines in the graphic plating process, due to high potential, the coating exceeds the film thickness, the formation of clip film caused by

short circuit.

2. the anti-coating layer is too thin, electroplating because the coating exceeds the film thickness, the formation of PCB clip film, especially the smaller the line spacing, the easier it is to cause short

circuit of clip film.

Improving method of plating clip film in the process of multilayer pcb proofing

1. increase the thickness of the coating: choose the appropriate thickness of the dry film, if it is a wet film can be printed with a low mesh screen, or by printing two wet films to increase the film

thickness.

2. the plate graphic distribution is not uniform, can be appropriate to reduce the current density (1.0~1.5A) plating. In daily production, for the reason of ensuring the output, we usually control the

plating time as short as possible, so the current density used is generally between 1.7 and 2.4A.

In this way, the current density obtained on the isolated area will be 1.5 to 3.0 times that of the normal area, which often causes the coating height to exceed the film thickness in the small distance

on the isolated area, the film is not clean after the film is removed, and the phenomenon of anti-coating on the edge of the line will appear in severe cases, resulting in short circuit of the clip film,

and the welding resistance thickness on the line will be thin.