WIRING SUBSTRATE AND METHOD FOR MANUFACTURING THE SAME

摘要

A wiring substrate includes a core substrate, and a build-up layer including conductor layers and insulating layers alternately laminated on the substrate and via conductors formed in the insulating layers, each insulating layer having a coating layer and a support layer stacked on the coating layer such that the support layer has surface on which a conductor layer is laminated and the coating layer is covering a conductor layer, each via conductor connecting two conductor layers through an insulating layer. The coating layer has a thickness greater than that of the support layer and includes inorganic filler at content rate of 65 to 85% by mass, and the support layer includes inorganic filler at different content rate such that thermal expansion coefficient of the coating layer is smaller than that of the support layer and the coefficients of the coating and support layers have difference of 30 ppm/° C. or less.

主权项

1. A wiring substrate, comprising:
a core substrate; and a build-up layer formed on the core substrate and comprising a plurality of conductor layers, a plurality of insulating resin layers and a plurality of via conductors such that the conductor layers and the insulating resin layers are alternately laminated on the core substrate and that the via conductors are formed in the insulating resin layers, each of the insulating resin layers being a two-layer insulating layer comprising a coating insulating layer and a support insulating layer stacked on a surface of the coating insulating layer such that the support insulating layer has a surface on which a respective one of the conductor layers is laminated and that the coating insulating layer is covering a respective one of the conductor layers on an opposite side with respect to the support insulating layer, each of the via conductors being penetrating through the two-layer insulating layer and connecting two of the conductor layers through a respective one of the insulating resin layers, wherein the coating insulating layer has a thickness which is greater than a thickness of the support insulating layer and includes inorganic filler at a content rate in a range of from 65% by mass to 85% by mass , and the support insulating layer includes inorganic filler at a content rate different from the content rate of the coating insulating layer such that a thermal expansion coefficient of the coating insulating layer is smaller than a thermal expansion coefficient of the support insulating layer and that the thermal expansion coefficients of the coating and support insulating layers have a difference of 30 ppm/° C. or less.