| 摘要 |
PURPOSE:To reduce generation of a smear and to improve reliability of a multilayer printed circuit board and yield of a product by providing an air gap in a hole between layers of a multilayer plates when a plurality of multilayer plates are superposed and a hole is opened. CONSTITUTION:A plurality of multilayers 1 in which a metal foil circuit layer and a resin layer made of resin immersed base material, etc., are laminated are superposed, and a spacer 2 is interposed between the respective multilayer plates 1. A hole is opened at a predetermined position by a drill 3 in this state. In this case, a hole 4 corresponding to the opening part is formed at the spacer 2. The diameter D of the hole 4 is desirably larger than the diameter (d) of the hole formed at the multilayer plate 1 by the drill 3. An air gap is formed by the hole 4 formed at the spacer 2 to effectively suppress the generation of a smear and to easily post-treat cutting chips. |
