Abstract: A via 42 is formed in an ILD layer 40 of a semiconductor device 30, using an etch chemistry which is highly selective to an underlying transition metal oxy-nitride film 38. In one form, film 38 is a TiO.sub.x N.sub.y film which is graded in nitrogen and oxygen concentration, being nitrogen rich at the bottom and oxygen reach at the top of the film. One method for forming TiO.sub.x N.sub.y is to sputter deposit a titantium layer 34 onto the semiconductor device using a titanium target 52. Using the same target, a TiN layer 36 is deposited by flowing nitrogen into the deposition chamber. Consequently, a TiN layer 58 is deposited onto target 52. The TiN layer 58 is then sputtered off the target onto the semiconductor device until eventually pure titanium is again being sputtered onto the device. The resulting deposited film has a grade titanium concentration, which is then oxidized to form the graded TiO.sub.x N.sub.y film.