A patterned organic masking layer is formed outwardly of a feature layer to be etched. It has at least one feature pattern having a minimum feature dimension of less than or equal to 0.3 micron. The feature layer has a thickness which is to be etched to form the one feature pattern in the feature layer. The feature pattern is plasma etched into the feature layer using the masking layer as a mask. The plasma etching comprises at least one etching segment where at least 30% of said thickness of the feature layer is etched using an etching gas comprising one gas compound comprising carbon, hydrogen and at least one halogen present at greater than or equal to 70% concentration by volume as compared to all carbon, hydrogen and halogen containing gas compounds in the etching gas. Such plasma etching is conducted under conditions effective to produce at least that portion of the one feature pattern in the feature layer formed during the one etching segment to have a sidewall taper, if any, of less than or equal to 5° and an organic masking layer top outer surface roughness proximate the feature pattern at a conclusion of the etching segment which is characterizable by an average value less than 100 Angstroms. Such value is determinable by scanning electron microscopy as an average maximum size of all surface discernible objects of the patterned masking layer as measured and averaged along any 0.3 micron length of top outer surface from the one feature pattern. Other implementations are also contemplated.