| 摘要 |
PURPOSE:To easily manufacture a viahole having high reliability even with high density by almost forming the opening of the viahole only by an exposing step with optically curable resin. CONSTITUTION:An optically curable resin film 30 is formed on one main surface of a board 10 formed with a lower layer interconnection 20, a mask 62 having a pattern capable of shielding a light only at a part corresponding to a position to be formed with a viahole, is aligned, and the resin layer is selectively exposed with a suitable light source having a curing wavelength of the resin. The residue of the layer 30 at a position to be formed with the viahole is removed by etching, and the opening of the viahole is completely formed. A conductive layer 40 is formed on the layer 30, and an inner wall conductor 41 of the viahole and an upper layer interconnection 42 are formed. Thus, the viaholes of a small diameter can be simultaneously accurately formed in high density in small number of steps for a short time. |
