| 摘要 |
PURPOSE:To expose the inorganic fillers by O2 plasma ashing the second solder resist layer surface. CONSTITUTION:Inorganic fillers 5 are mixed with one another in the second solder resist layer 32. As for the inorganic fillers 5, calcium carbonate is used as an acid soluble filler. The mixed amount of the inorganic filler shall not exceed 50wt%. Accordingly, most of the inorganic fillers existing in the second solder resist layer 32 are to be hardly exposed in the surface. Since the O2 plasma ashing step is performed from the surface of the second solder resist layer 32, the layer 32 only comprising organic material is to be scraped off by the ashing step leaving the inorganic fillers 5 intact. Thus, the inorganic fillers 5 near the surface are to be exposed in the ashing surface of the second solder resist layer 32. Accordingly, the inorganic fillers 5 can be exposed in the whole surface of the second solder resist layer 32 evenly and in high density. |
