Method for patterning a layer of silicon, and method for fabricating an integrated semiconductor circuit

Abstract

A hard mask made from polysilicon is used to etch a layer to be patterned. The hard mask is patterned using a resist mask. The etching of the hard mask is carried out in such a way that the openings which are etched into the hard mask have inclined sidewalls. This reduces the cross section of the openings, with the result that smaller openings can be formed in the layer that is to be patterned than the openings which have been predetermined by the resist mask. The hard mask is etched using only HBr. The inclination of the openings etched into the hard mask can be set by way of the TCP power and/or the bias power of a TCP etching chamber, and/or by way of the HBr flow rate.