Patent ID: 7910836

Claim:
A multilayered printed circuit board comprising: a substrate; a plurality of conductor circuits formed over the substrate and including an outermost conductor circuit; at least one resin insulating layer formed over the substrate and between the conductive circuits; and a solder resist layer comprising one of a photo-setting resin and a thermo-setting resin, the solder resist further comprising an inorganic filler comprising a plurality of inorganic particles, the inorganic particles being dispersed in the solder resist layer in an amount and a size sufficient to decrease a thermal expansion coefficient of the solder resist layer such that a stress generated in the solder resist layer due to thermal expansion is moderated, wherein the solder resist layer is formed over the conductor circuits and resin insulating layer and provided as an outermost layer with respect to the conductor circuits and resin insulating layer, and the outermost conductor circuit has a pad portion exposed by an opening of the solder resist layer and configured to be connected to an IC chip; wherein said solder resist layer contains an elastomer having a content in a range from 1% to 20% by weight.