Patent ID: 8546264

Claim:
A method of etching radical reduced, gas chopped deep reactive ion etching comprising: a) conditioning a chamber comprising: i) discharging an etchant and a passivator in the chamber, wherein the passivator is polytetrafluoroethane (PTFE), and ii) ionizing at least some of the etchant and passivator in a plurality of passivation-etching cycles; such that the inside of the chamber comprises CF 2 and CF x , wherein x is 1, 2, or 3, having a CF 2 /CF x ratio higher than if the chamber was not conditioned, wherein subsequent steps b) to d) take place inside said chamber; b) etching a material using a means for gas chopped ion etching comprising: i) the etchant; and ii) the passivator; c) ionizing at least some of the etchant and passivator of step b); and d) controlling a concentration of radicals produced by the ionizing of the etchant; such that a smooth sidewall is produced on the material being etched, wherein the smooth sidewall has a surface roughness of less than 5 nm RMS.