发明授权
US06277700B1 High selective nitride spacer etch with high ratio of spacer width to deposited nitride thickness 失效
高选择性氮化物间隔物蚀刻,间隔物宽度与沉积的氮化物厚度的高比率

High selective nitride spacer etch with high ratio of spacer width to deposited nitride thickness
摘要:
A method of etching silicon nitride spacers beside a gate structure comprising: providing a gate electrode over a gate oxide layer on a substrate. A liner oxide layer is provided over the substrate and the gate electrode. A silicon nitride layer is provided over the liner oxide layer. The invention's nitride etch recipe is performed in a plasma etcher to anisotropically etch the silicon nitride layer to create spacers. The nitride etch recipe comprises a main etch step and an over etch step. The main etch step comprises the following conditions: a Cl2 flow between 35 and 55 molar %, a He flow between 35 and 55 molar %, a backside He pressure between 4 and 10 torr; and a HBr flow between 7.5 and 12.5 molar %; a pressure between 400 to 900 mTorr; at a power between 300 and 600 Watts. The etch recipe provides a spacer width to nitride layer thickness ratio of about 1:1 and does not pit the Si substrate surface.
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