| 摘要 |
PROBLEM TO BE SOLVED: To improve the yield of a built-up substrate by forming a thermosetting resin film on metallic foil and forming an embossed shape with not less than specified depth and with the pitch of a specified range. SOLUTION: Resin 2 being the inter-layer insulating film of built-up layer is loaded on copper foil or an organic film 1 to be a carrier, and an embossed shape with the depth of not less than 0.005 mm and with the pitch of 0.05 mm to 20 mm is formed on the surface of the resin film 2. It is brought into contact with the copper pattern 4 of a printed wiring board 3, is placed in vacuum, is sufficiently exhausted and is pressurized/heated. Since flatness after formation can be secured by making the width of a groove to be smaller than a distance where resin 2 circulates at the time of heating, the yield of the built-up substrate can be improved. |
