| 摘要 |
PROBLEM TO BE SOLVED: To avoid forming voids in a plating process when via-holes are formed. SOLUTION: Bottom-closed via-holes IVH(interstitial via-holes) 100 are composed of holes, ands 101, a panel plated layer 70 and an electrolytic plated layer 80. The holes are formed by drilling until reaching a sheet 10, using an NC drill. The opening of each hole, i.e., the land 101 is rounded like a circular arc and the inner diameter thereof gradually decreases toward the inner layer. |
