| 摘要 |
PROBLEM TO BE SOLVED: To eliminate warping of a board and devise reliable inter-layer via- connections by heating an insulation layer for coupling circuit boards having connecting electrodes electrically connected to vias at specified temp. to lower the viscosity below specified leaving it in this temp. range to harden a thermosetting resin layer. SOLUTION: A Cu foil 102 is overlaid on a polyimide film 101 as an insulation sheet, a CO2 gas laser beam reduced in diameter to irradiated it through the polyimide film to form blind vias 103 with the surface Cu foil acting as a stopper, the vias 103 is filled with Cu to form Cu vias 104 with the surface Cu foil 102 used as an electroplating electrode, and electroplating 105 is made. On the back face a protective film 106 is pasted to leave a resist 107 at desired parts, the resist is stripped, the exposed Cu pattern 108 surface is electroless- plated 109, and adhesive 110 is applied on a film circuit surface and thermally compressed. |
