US Patent 8476146 Reducing wafer distortion through a low CTE layer

Provided is a method of fabricating a semiconductor device. The method includes forming a first layer on a first side of a first silicon wafer. The first silicon wafer has a second side opposite the first side. The first layer has a coefficient-of-thermal-expansion (CTE) that is lower than that of silicon. The method includes bonding the first wafer to a second silicon wafer in a manner so that the first layer is disposed in between the first and second silicon wafers. The method includes removing a portion of the first silicon wafer from the second side. The method includes forming a second layer over the second side of the first silicon wafer. The second layer has a CTE higher than that of silicon.