A method for etching of sub-quarter micron openings in insulative layers for contacts and vias is described. The method uses hardmask formed of carbon enriched titanium nitride. The hardmask has a high selectivity for etching contact and via openings in relatively thick insulative layers. The high selectivity requires a relatively thin hardmask which can be readily patterned by thin photoresist masks, making the process highly desirable for DUV photolithography. The hardmask is formed by MOCVD using a metallorganic titanium precursor. By proper selection of the MOCVD deposition conditions, a controlled amount of carbon is incorporated into the TiN film. The carbon is released as the hardmask erodes during plasma etching and participates in the formation of a protective polymer coating along the sidewalls of the opening being etched in the insulative layer. The protective sidewall polymer inhibits lateral chemical etching and results in openings with smooth, straight, and near-vertical sidewalls without loss of dimensional integrity.