Reactive Ion Etch Slope Control for Images Formed in Silicon Nitride
Original Publication Date: 1986-Jan-01
Included in the Prior Art Database: 2005-Mar-08
Effective tailoring of plasma enhanced CVD (chemically vapor deposited) silicon nitride via sidewall slopes during reactive ion etching (RIE) with argon ion implant of the nitride insulator is described in this article. By reducing the sidewall slope of the inter-metal contact hole, reliability is enhanced through the elimination of metal discontinuities in the second metal layer. The utilization of a low energy (30 KeV) argon ion implant creates a faster etching of nitride (approximately 500 A thick) at the film surface, without radiation-induced device effects. The use of reactive ion etching maintains the small etched image bias and tolerances values required in advanced semiconductor products. Modification of a nitride slope during RIE from 59 degrees to 39 degrees may be achieved by low energy argon ion implant before RIE.