Patent ID: 8404597
Filing Date: 2013-03-26
Classification: H01L

Abstract:
1. A device for stopping an etching process, the device comprising: an etch layer comprising a first material and an etch layer thickness; an intermediate layer comprising a second material and an intermediate layer thickness; and a stop layer comprising a third material, the stop layer having a stop layer thickness, wherein the intermediate layer thickness is such that a ratio of the etch layer thickness to the intermediate layer thickness is at most 3 times a first etch selectivity for a fluorocarbon etchant between the first material and the second material, wherein the first and second materials are such that the first etch selectivity for the fluorocarbon etchant between the first and second materials is at least a ratio of 5:1, wherein the second and third materials are such that a second etch selectivity for a fluoro-methane etchant between the second and third materials is at least a ratio of 5:1, wherein the etch layer comprises an inclusion in a region to be etched for forming a via contact, and wherein the inclusion has an etching rate different than the etching rate of the first material when exposed to the fluorocarbon etchant.