Patent ID: 8481861

Claim:
A printed circuit board comprising: a board having a substrate formed of a first material having a first coefficient of thermal expansion, and having circuit traces; a die secured to said board, said die having circuit traces electrically connected to said board circuit traces, and said die having a base formed of a second material having a second coefficient of thermal expansion different than said first coefficient of thermal expansion; an interposer material positioned between said die and said board, said interposer having an electrical connection connecting said die circuit traces to said board circuit traces, said interposer being formed of a third material having a coefficient of thermal expansion intermediate said first and second coefficients of thermal expansion; wherein said interposer includes a base material with a plurality of openings, said openings receiving a conductive material to connect said die to said board; and wherein said interposer is formed of a polyimide of bismuth telluride.