A novel NF/sub 3/-HDP-CVD process for STI-filling in sub-90 nm DRAM and beyond

A complete filling of the shallow trench isolations (STI) in sub-90 nm DRAM is realized with the novel NF/sub 3/-HDP-CVD process. The gap-fill capability of the NF/sub 3/-HDP-CVD increased dramatically as NF/sub 3/ gas is added to the conventional SiH/sub 4//O/sub 2/ chemistry of HDP-CVD process. The effect of the NF/sub 3/-HDP-CVD processed STI is investigated by analyzing the transistor characteristics and yield in 512 M DRAM.