| 摘要 |
PURPOSE:To improve position accuracy of a small diameter hole and to enable a smooth through-hole by etching away a metallic layer at a specified hole processing position, making a hole smaller than the specified hole diameter minus 0.05mm by a laser, and drilling the hole to the specified diameter. CONSTITUTION:A base material is formed by forming a metallic layer 6 on both sides of an insulating board 5. The metallic layer 6 of a specified hole processing position 7 of the base material is removed by etching, etc. The base material is processed by laser to provide a preliminary hole 8 whose hole diameter is smaller than a specified hole diameter minus 0.05mm. Then, the hole 8 is drilled to the specified hole diameter. Thereby, it is possible to improve position accuracy of a small diameter hole, to improve life of a hole processing drill and to acquire a smooth through-hole 9. |
