Patent ID: 7709942

Claim:
A semiconductor package comprising: a base plate having a first surface and a second surface; at least one semiconductor constructing body including: (i) a semiconductor substrate which is formed on said first surface of the base plate and which has a plurality of connection pads formed on one surface thereof, (ii) a plurality of columnar external connection electrodes which are electrically connected to the connection pads, (iii) a plurality of interconnections, which are formed over said one surface of the semiconductor substrate, each of the interconnections having a first end connected to one of the connection pads and a second end connected to one of the columnar external connection electrodes, such that each of the interconnections is positioned between and electrically connects one of the connection pads and one of the columnar external connection electrodes, and (iv) a sealing film which is provided around the columnar electrodes and which covers the interconnections and said one surface of the semiconductor substrate, wherein an upper surface of the sealing film is flush with upper surfaces of the columnar electrodes; an insulating layer which is formed on said first surface of the base plate and covers a peripheral surface of the semiconductor constructing body, wherein an upper surface of the insulating layer is flush with the upper surface of the sealing film; a first upper insulating film which covers the entire upper surface of the insulating layer and an upper surface of the semiconductor constructing body except for a central portion of the upper surface of each of the columnar external connection electrodes, wherein the first upper insulating film has a flat upper surface, and wherein the first upper insulating film comprises a sheet of a build-up material or a prepreg material including a thermosetting resin which has been placed in a semi-set state on the upper surfaces of the insulating layer and the semiconductor constructing body and which has then been pressed and heated by a heating plate on an upper surface of the sheet so as to set the thermosetting resin and form the flat upper surface of the first upper insulating film; a plurality of upper interconnections, each of which is formed on the first upper insulating film and over the insulating layer and includes at least one interconnection layer, at least some of the upper interconnections being connected to the external connection electrodes of the semiconductor constructing body; and a plurality of lower interconnections, each of which is formed on said second surface of the base plate and includes at least one interconnection layer, at least some of the lower interconnections being electrically connected to the upper interconnections.