UHV-Wafer Bonding
Abstract
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S. Senz
Wafers are chemically cleaned, terminated by hydrogen and pre-bonded in a clean-room. The wafer pairs are transferred into the UHV system via a load-lock. Inside the UHV system the pairs are separated by knifes inserted at the rim. Heating up to about 450ºC releases the hydrogen termination. The resulting surface has a high density of dangling bonds and can bond at room temperature with covalent bonds directly to a second wafer. Compared to hydrophilic and hydrophobic bonding the thermal budget of this process is lower. The schematic drawing shows bonding of silicon to silicon, but UHV wafer bonding can be performed with all chemically reactive and sufficiently flat surfaces.
