Process Challenges During CVD Oxide Deposition on the Backside of $20-\mu m$ Thin 300-mm Wafers Temporarily Bonded to Glass Carriers

A temporary carrier system is evaluated during several backside processing steps on ultra-thin wafers, down to
$20\ \mu\mathrm{m}$
, with the main focus centered on chemical vapor deposited (CVD) oxides. Such wafers hold the risk of deformation and even delamination during the deposition step. A step-by-step investigation reveals the deformation/delamination mechanism to be highly dependent on the oxide deposition conditions rather than the deposition temperatures. Controlling the stress in the oxide layer enables both high temperature and low temperature oxides to be successfully deposited on the backside of ultra-thin wafers. The experimental results are corroborated with finite element simulations.