| 摘要 |
<p>A method of etching a dielectric layer (20) on a substrate (25) with high etching selectivity, low etch rate microloading, and high etch rates is described. In the method, the substrate (25) is placed in a process zone (55), and a plasma is formed from process gas introduced into the process zone (55). The process gas comprises (i) fluorocarbon gas for etching the dielectric layer (20) and for forming passivating deposits (46) on the substrate (25), (ii) carbon-oxygen gas for enhancing formation of the passivating deposits (46), and (iii) nitrogen-containing gas for etching the passivating deposits (46) on the substrate (25). The volumetric flow ratio of fluorocarbon:carbon-oxygen: nitrogen-containing gas is selected to provide a dielectric to resist etching selectivity ratio of at least 10:1, an etch rate microloading of < 10%, and a dielectric etch rate of at least 100 nm/min. Preferably, the volumetric flow ratio of fluorocarbon:carbon-oxygen:nitrogen-containing gas is selected so that the rate of formation of passivating deposits (46) on the sidewalls (48) of the freshly etched features (45) is approximately equal to the rate of removal of the passivating deposits (46). <IMAGE> <IMAGE></p> |
