Analysis of a fence-free platinum etch process

Abstract

In a previous study we describe a high flow. Cl2-rich dry etch (DE) process which yields fence-free Pt etch structures. In that work we identify the existence of a transient fence defect, and show that it can cause the formation of an extremely shallow sidewall in the fully etched structure. We now expand upon this effort by documenting how several of the key DE parameters individually influence the sidewall profile. Through a series of four experiments, we found that: (a) the inclusion of Ar into the Cl2/CF4 gas mix promotes the formation of fencing; (b) insufficient total gas flow induces DE cone formation localized to the sidewalls of the etched Pt electrodes; (c) the inclusion of CF4 in the gas mix is unnecessary; and (d) the choice of self-bias voltage influences the critical dimension control and sidewall angle of the etched Pt electrodes.