Chemical-Mechanical Polishing For III-V Wafer Bonding Applications: Polishing, Roughness, And An Abrasive-Free Polishing Model

Chemical mechanical polishing (CMP) of III-V (and other materials) is an important component of subsequent wafer bonding or epitaxial growth. For example, transferred exfoliated layers possess roughness on the order of tens of nanometers and epitaxial layers may possess surface roughness that prevents subsequent bonding. Standard polishing processes are too aggressive and remove material at rates on the order of microns per minute. This paper develops a more controlled CMP process for Indium Phosphide (InP), which removes the RMS roughness to below 1 nm with a removal rate of 5 nm per minute. The technique is characterized at different time intervals and roughness values. A model for abrasive-free CMP is also developed to expand upon current models