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Blind hole manufacturing process of HDI PCB

1. When the blind hole is designed without stacking holes and the inner layer is completed with a copper thickness of 17.1 mm: inner layer patterning - pressing - browning - laser drilling - debrowning - copper sinking - whole board filling and electroplating - slicing Analysis - Inner Layer Patterning - Inner Layer Etching - Inner Layer AOI - Post Process.

2. Blind hole stacking design, and the inner layer is completed with a copper thickness of 17.1 mm: inner layer pattern production - pressing - browning - laser drilling - debrowning - copper sinking - whole board filling and electroplating - slice analysis - Copper reduction - inner layer patterning - inner layer etching - inner layer AOI - post process.

3. When the inner layer is completed with a copper thickness of 17.1 mm, the inner layered holes and non-stacked holes are designed, and the blind holes are made by filling and leveling: inner layer pattern production - browning - pressing - browning - laser drilling - debrowning - Copper Immersion - Hole Filling Electroplating - Slice Analysis - Inner Layer Pattern - Inner Layer Etching - Inner Layer AOI - Post Process.

It can be seen from the above analysis that when the inner layer blind hole is designed as a stacked hole, in order to ensure the filling of the blind hole, a larger filling parameter must be used to fill the blind hole, and then the surface copper should be reduced to the required thickness. Therefore, in the above three processes, the thickness of the surface copper is controlled according to the adjustment of the hole filling parameters. At present, the common hole filling processes include resin plug hole and electroplating hole filling. The resin plug hole is filled with epoxy resin by plating copper on the wall of the via hole, and finally copper plating on the surface of the resin, the effect is that the hole can be turned on. And there are no dents on the surface, which does not affect the welding. Electroplating fills the vias directly by electroplating, without voids, which is good for welding, but requires high process capabilities.