Patent ID: 6432318
Filing Date: 2002-08-13
Classification: H01L

Abstract:
A method of plasma etching an oxide layer to have striations below a first selected value and to have a loss of critical dimensions below a second selected value, comprising the steps of:flowing a gas mixture into a plasma reactor containing a substrate containing an oxide layer overlaid by a patterned photoresist layer, said gas mixture comprising a non-zero first amount of a first gas consisting of hexafluorobutadiene, a non-zero second amount of a second gas selected from the group of fluorocarbons and hydrofluorocarbons other than hydrogen-free flurocarbons having F/C ratios of less than two, a third amount of a third gas selected from the group of oxygen-containing compounds consisting of oxygen and carbon monoxide, and a non-zero fourth amount of a noble diluent gas, said first, second, and third amounts being chosen so that a compositional ratio of (Fâ€”H)/(Câ€”O) is at least 1.5 and no more than 2.0, wherein F, H, C, and O are respective atomic amounts of fluorine, hydrogen, carbon, and oxygen in said first, second, and third amounts of said first, second, and third gases respectively; and exciting said gas mixture into a plasma to etch said oxide layer to have striations below said first selected value and to have said loss of critical dimensions below said second selected value.