Cryogenic etching of porous material

Abstract

With the shrinkage of chip feature sizes, porous materials are widely used in microelectronics. However, they are facing severe challenges in plasma etching, as the reactive radicals can diffuse into the interior of material and damage the material, which is called plasma induced damage. In this paper, we review two kinds of etching processes based on low chuck temperature, i.e. cryogenic etching. By lowering the chuck temperature, either the etching by-products or the precursor gas can condense in the porous material, and thus preventing the radicals from diffusing and protect the material from being damaged by plasma. The technology of cryogenic filling inside the porous material is simple but effective, which allows it to have a good application prospect.