Patent ID: 7723815
Filing Date: 2010-05-25
Classification: H01L

Abstract:
1. A composite structure for matching a coefficient of thermal expansion of a read out integrated circuit ROIC to a coefficient of thermal expansion of an infrared detector chip in order to provide a thermally matched hybridized semiconductor chip assembly, comprising: the ROIC having a top and a bottom surface, said ROIC having a coefficient of thermal expansion which is different than the coefficient of thermal expansion of the infrared detector chip; a substrate having a surface that is direct wafer bonded to a bottom surface of the ROIC chip to form a direct wafer bonded composite structure, where the substrate surface is in direct physical contact with the bottom surface of the ROIC chip; and wherein said direct wafer bonded composite structure has a coefficient of thermal expansion that at least substantially matches the coefficient of thermal expansion of the infrared detector chip, thereby providing thermal matching between the ROIC and the infrared detector chip; wherein said composite structure is comprised of three direct wafer bonded layers, with a first layer being said ROIC being comprised of a first semiconductor material, wherein said coefficient of thermal expansion of the ROIC is less than said coefficient of thermal expansion of said infrared detector chip, a second layer comprising a second semiconductor material with a coefficient of thermal expansion greater than said coefficient of thermal expansion of said infrared detector chip, and a third layer comprising a third semiconductor material with a coefficient of thermal expansion less than said coefficient of thermal expansion of said infrared detector chip, and wherein the second layer is disposed between the ROIC and the third layer.