Communication-Fluorinated Plasma Treatments Using PTFE Substrates for Room-Temperature Silicon Wafer Direct Bonding

We introduced polytetrafluoroethylene (PTFE) substrates and silicon wafers into oxygen plasma to form fluorinated oxide layers on the silicon surfaces, similar to sputtering processes. After a short plasma treatments (similar to 60 s), fluorinated oxide layers were formed and could be controlled by adjusting the size of the PTFE substrates. Two wafers were brought into contact at room temperature (similar to 25 degrees C), and the surface energy was significantly improved to similar to 1.8 J/m(2), even without employing heating. This surface energy is sufficiently high to withstand subsequent mechanical processing. No defects or nanopores were observed in the bonding interface. (C) 2016 The Electrochemical Society. All rights reserved.