Lam Research Corporation
METHOD OF ACHIEVING HIGH SELECTIVITY FOR HIGH ASPECT RATIO DIELECTRIC ETCH

Abstract:

Various embodiments herein relate to methods and apparatus for etching a feature in a substrate. Often, the feature is etched in the context of forming a DRAM device. The feature is etched in dielectric material, which often includes silicon oxide. The feature is etched using chemistry that includes WF.sub.6. Although WF.sub.6 is commonly used as a deposition gas (e.g., to deposit tungsten-containing film), it can also be used during etching. Advantageously, the inclusion of WF.sub.6 in the etch chemistry can increase the etch rate of the dielectric material, as well as increase the selectivity of the etch. Unexpectedly, these benefits can be realized without any increase in capping.