TECHNOLOGIES: permanganate cleaning of holes in multi layer boards ÏÎ 400
The permanganate cleaning removes resin smears from the ends of inner contact pads in MLBs as well as generates on the hole-wall a rough surface topography which is a critical requirement to provide a perfewct adhesion of the metallization barrel to the hole wall.
ÏÎ 400 The Basic Process Stages and Materials Used
¹ |
Operation |
Òåmperature, ºÑ |
Treatment time, min. |
Note |
1
|
Sensitization
(ÏÎ 401)
|
65 - 70
|
8-10
|
Efficiently removes residues after drilling as well as both sensitize and conditions the hole-wall to attain the optimum processing in the following permanganate tank. |
2
|
Permanganate processing (ÏÎ 402)
|
65 - 70
|
8-10
|
Produces the irregular microrough surface topography for a better catalyst absorption. It considerably increases the copper/hole-wall adhesion and eliminates voids, blisters, pull-away due to the resin smears available after drilling. |
3
|
Neutralization
(ÏÎ 403)
|
38 - 43
|
3-5
|
The full neutralization and the removal of manganese residues from the holes occur.
The availability of a glass-etching component assures the optimum matting of glass fiber and thus promotes the copper to glass-part-of-wall adhesion. |
ÏÎ 400 treatment fails to show any significant occurrence of excessive etching of resin and the exposed fiber glass fabric as the result, therefore there is no evidence for such defect as the metal penetration along glass fibers.
