| abstract |
An etching gas for plasma etching a channel hole, a gate trench, a stator case contact, a capacitor hole, a contact hole and the like in a Si-containing layer on a substrate and a plasma etching method using the same are disclosed. The etching gas is trans-1,1,1,4,4,4-hexafluoro-2-butene; Cis-1,1,1,4,4,4-hexafluoro-2-butene; Hexafluoroisobutene; Hexafluorocyclobutane (trans-1,1,2,2,3,4-); Pentafluorocyclobutane (1,1,2,2,3-); Tetrafluorocyclobutane (1,1,2,2-); Or hexafluorocyclobutane (cis-1,1,2,2,3,4-). The etching gas improves selectivity between the Si-containing layer and the mask material, lessens damage to the channel region, provides a linear vertical etch profile, and reduces warpage in the patterned high aspect ratio structure. |