1:40 PM - 1:42 PM
[SO-PS-03-06] Chemical Mechanical Polishing for Indium Bond Pad Damascene Processing
In this paper chemical mechanical polishing (CMP) of indium is investigated, with the goal of obtaining high quality indium via bond pads for later cryo-3D integration of quantum computing chips, through bonding between these via pads and indium bumps. Higher removal rates were obtained with soft CMP pads than with hard pads. The latter led to deep scratching, while this effect was much more limited for soft pads. For soft pad CMP on patterned wafers, indium is cleared well from the Si field in structured areas, leading to relatively high-quality indium surfaces inside pads, suitable for 3D die-to-die and wafer-to-wafer bonding.