Patent ID: 7768132

Claim:
A circuit device comprising: a substrate and a circuit element mounted on the substrate, the substrate comprising: a first wiring layer and a second wiring layer laminated while interposing an insulating layer therebetween, wherein the insulating layer is made of resin containing filler; a first connecting portion formed continuously from the first wiring layer and buried in the insulating layer, wherein the first connecting portion protrudes upward; a second connecting portion formed continuously from the second wiring layer and buried in the insulating layer, wherein the second connecting portion protrudes downward; and wherein the first connecting portion and the second connecting portion contact each other at a position within the insulating layer in a thickness direction of the insulating layer; wherein the first wiring layer and the first connecting portion are formed of one piece of metal; wherein the first wiring layer is formed on the bottom surface of the insulating layer; wherein the second wiring layer is formed on the upper surface of the insulating layer; wherein a planar size of the first connecting portion is smaller than the size of the first wiring layer; wherein a planar size of the second connecting portion is smaller than the size of the second wiring layer; wherein an upper surface of the first wiring layer and the lower surface of the insulating layer are located on a same plane as one another; and wherein a lower surface of the second wiring layer and the upper surface of the insulating layer are located on the same plane as one another.