树脂绝缘层和导体层，能够充分确保之间的粘附力，提供了极好的多层布线基板的连接可靠性。 多层布线板（10）具有通过层叠多个树脂绝缘层的（33至36）和多个导电层（42）交替的多层化的组装结构。 树脂绝缘层（33至36），从下绝缘层（51）设置在下部绝缘层（51）和（52）上的上绝缘层制成，所述上绝缘层的表面上（52） 形成导电层（42）。 上绝缘层（52）形成为比下部绝缘层（51）薄，二氧化硅填料占据上绝缘层（52）的体积比为二氧化硅填料和玻璃布占据下部绝缘层（51） 小于的体积比。

The adhesion between the resin insulating layer and the conductor layer can be sufficiently secured, provides excellent multilayer wiring board in connection reliability.
Multilayer wiring board (10) has a built-up structure in which multilayered by stacking a plurality of resin insulation layer (33-36) and a plurality of conductive layers (42) alternately. Resin insulating layer (33-36) is made from the lower insulating layer (51) an upper insulating layer provided on the lower insulating layer (51) and (52), on the surface of the upper insulating layer (52) conductor layer (42) is formed. The upper insulating layer (52) is formed thinner than the lower insulating layer (51), the volume rate of the silica filler occupying the upper insulating layer (52) is a silica filler and glass cloth occupying the lower insulating layer (51) less than the volume percentage of.