Tungsten etch process with high selectivity to photoresist

A process is disclosed for the etching of a tungsten layer on a semiconductor wafer through a photoresist mask to form a pattern of tungsten lines on the wafer. The process is characterized by a high selectivity to photoresist material and resistance to lateral etching or undercutting of the tungsten beneath the photoresist mask resulting in good profile control, i.e., low critical dimension loss in the etched tungsten pattern. The process comprises flowing SF6, N2, Cl2 gases into an etch chamber while maintaining a plasma in the chamber. In a preferred embodiment, the wafer in the etch chamber is immersed in a magnetic field during the etch to further enhance the selectivity of the etch to photoresist.