Patent ID: 7696617

Claim:
An interposer interposed between a semiconductor element and a package having a portion for mounting said semiconductor element to electrically connect a plurality of electrode terminals of the semiconductor element to a plurality of pad portions of the package, said interposer comprising a plate-like interposer body obtained by sticking together a first plate forming an upper exposed surface of the interposer to which the semiconductor element is connected, being made of silicon and having a first coefficient of linear thermal expansion the same as, or close to, that of silicon constituting a principal material of said semiconductor element, and a second plate forming a lower exposed surface of the interposer to which the package is connected and being made of a material having a second, different coefficient of linear thermal expansion the same as, or close to, that of an insulating resin constituting a principal material of said package, a plurality of first terminals protruding from a surface of the first plate of said interposer body and joined to the plurality of electrode terminals of said semiconductor element, and a plurality of second terminals protruding from a surface of the second plate of said interposer body and joined to said plurality of pad portions of said package.