Patent ID: 8742568

Claim:
A semiconductor device, comprising: a circuit board section; and a semiconductor chip, disposed over the circuit board section, and having a size substantially equivalent to the size of said circuit board section, viewed from the side of a substrate surface of said circuit board section; wherein said circuit board comprises: a first insulating layer, through which an electric conductor extends; a first circuit layer, provided in one side of said first insulating layer and coupled to said electric conductor; a second insulating layer, covering said first circuit layer and having an aperture formed over a portion of said first circuit layer; a second circuit layer, provided in the other side of said first insulating layer and coupled to said electric conductor; a third insulating layer, covering said second circuit layer; and a solder layer, provided in the aperture of said second insulating layer, and provided over said first circuit layer, wherein an average coefficient of thermal expansion (A) of said first insulating layer in the direction along the substrate surface in a temperature range from 25 degrees C. to its glass transition point is equal to or higher than 3 ppm/degrees C. and equal to or lower than 30 ppm/degrees C., wherein an average coefficient of thermal expansion (B) of said second insulating, layer in the direction along the substrate surface in a temperature range from 25 degrees C. to its glass transition point is equivalent to all average coefficient of thermal expansion (C) of said third insulating layer in the direction along the substrate surface in a temperature range from 25 degrees C. to its glass transition point, wherein the average coefficient of thermal expansion (B) of said second insulating layer in the direction along the substrate surface in the temperature range from 25 degrees C. to its glass transition point and the average coefficient of thermal expansion (C) of said third insulating layer in the direction along the substrate surface in the temperature range from 25 degrees C. to its glass transition point are larger than the average coefficient of thermal expansion (A) of said first insulating layer, wherein a difference between the average coefficient of thermal expansion (A) of said first insulating layer and the average coefficient of thermal expansion (B) of said second insulating layer, and a difference between the average coefficient of thermal expansion (A) of said first insulating layer and the average coefficient of thermal expansion (C) of said third insulating layer are equal to or higher than 5 ppm/degrees C. and equal to or lower than 35 ppm/degrees C., and wherein a side surface of said circuit board section and a side surface of said semiconductor chip are formed to be coplanar relation.