| 摘要 |
<p>PROBLEM TO BE SOLVED: To realize high density of a wiring pattern and improve adherence between ball pads and a resin board, by specifying the thicknesses of a first conducting layer for forming a wiring pattern and a second conducting layer for forming ball pads, and the surface roughness of the surfaces of the first and second conducting layers. SOLUTION: Copper foils 4, 5 are laminated on both surfaces of a prepreg 1, and a base board 6 is formed by vacuum press. Through holes 2 are formed on the base board 6 and filled with conductive resin 3. After that, the copper foils 4, 5 are etched, a wiring pattern 7 is formed on a chip component mounting surface 1a side, and ball pads 8 are formed on a mother board bonding surface 1b side. A copper foil having a thickness of d1 less than thickness d2 of the copper foil 5 laminated on the mother board bonding surface 1b and/or a copper foil having surface roughness of a sticking surface 4a smaller than that of a sticking surface 5a of the copper foil 5 are used as the copper foil 4 laminated on the chip component mounting surface 1a.</p> |
