Dual damascene etch processes

摘要

A dual damascene trench etching process includes a two-step BARC etching process, a first BARC etch step using a fluorocarbon-based plasma, and a second BARC etch step using an O₂/N₂-based plasma. The first BARC etch step removes a first portion of the BARC covering a dielectric stack using a fluorocarbon-based plasma. The second BARC etch step removes a second portion of the BARC covering the dielectric stack using a O₂/N₂ based plasma. The dual damascene trench etching process may further include a BARC etch back process to remove a further portion of the BARC not covering the dielectric stack. The dual damascene trench etching process further includes a low-k dielectric etching process that etches trenches in a low-k dielectric layer in the dielectric stack and that avoids the use of argon in order to prevent facet formation.