| 摘要 |
A plasma etch chemistry and etch methodology is provided to improve critical dimension control for openings formed into and/or through a semiconductor thin film. According to an embodiment, the plasma etch chemistry includes an etchant mixture comprising a first etchant of the formula CxHyFz (where x>=2, y>=1 and z>=2) and a second etchant other than the first etchant to form the openings. The relationship of x, y and z may be such that y+z equals an even number <=2x+2. According to an alternative embodiment, the plasma etch chemistry further includes strained cyclic (hydro)fluorocarbon. The plasma etch chemistry may be used to form openings in the layer in a single-etch step. In a further embodiment, the plasma etch chemistry described herein may etch less than the entire thickness of the layer, and a second plasma etch chemistry substantially free of the first etchant and strained cyclic (hydro)fluorocarbons etches the remainder of the layer to form the openings. Such an etch methodology advantageously reduces the risk of etching the materials underlying the layer.
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