| 摘要 |
PROBLEM TO BE SOLVED: To provide a multilayered printed wiring board of a structure, wherein a via hole is hardly peeled from a conductor circuit on the lower layer, which is the layer under an upper layer of a bonding agent layer. SOLUTION: A board 20 formed with an opening 36 for via hole formation use is dipped in a chromic acid for one minute and epoxy resin particles (the mean particle diameter in the 7.2 pts.wt. of 1.0μm, and the mean particle diameter in the 3.09 pts.wt. of 0.5μm.) in the surface of a bonding agent layer 34 are removed by dissolving. Moreover, by removing through dissolving epoxy resin particles (the mean particle diameter in the 14.49 pts.wt. of 0.5μm.) in the surface of an insulating agent layer 32, which is the layer under this layer 34, the insulating agent layer 32, which has a mean particle diameter smaller than that in the layer 34 on the side of the upper layer, on the side of the lower layer is made to erode more than the layer 34 and the sidewall 36a of this opening 36 is made to bend toward the inside of the opening 36. After that, an electroless copper-plated film 40 and an electrolytic copper-plated film 44 are formed, whereby a via hole 47 is completed. |
