| abstract |
Methods of etching silicon nitride material, and more particularly, etching nitride selective to silicon dioxide or silicide, are disclosed. The methods include exposing a substrate having silicon nitride thereon to a plasma including at least one fluorohydrocarbon and a non-carbon containing fluorine source such as sulfur hexafluoride (SF 6 ). The plasma may also include oxygen (O 2 ) and the fluorohydrocarbons may include at least one of: trifluoromethane (CHF 3 ), difluoromethane (CH 2 F 2 ), and methyl fluoride (CH 3 F). In an alternative embodiment, the plasma includes one of hydrogen (H 2 ) and nitrogen trifluoride (NF 3 ) and one of tetrafluoromethane (CF 4 ) and octafluorocyclobutane (C 4 F 8 ). The methods are preferably carried out using a low bias voltage, e.g. <100 V. |