US Patent 7670927 Double-sided integrated circuit chips

A semiconductor structure and method of fabricating the structure. The method includes removing the backside silicon from two silicon-on-insulator wafers having devices fabricated therein and bonding them back to back utilizing the buried oxide layers. Contacts are then formed in the upper wafer to devices in the lower wafer and wiring levels are formed on the upper wafer. The lower wafer may include wiring levels. The lower wafer may include landing pads for the contacts. Contacts to the silicon layer of the lower wafer may be silicided.