Patent ID: 9466523
Filing Date: 2016-10-11
CPC Classification: H01L

Claim Text:
1. A method of forming contact holes through a dielectric layer comprising: forming an underlying dielectric layer over a substrate; subsequently depositing a first dielectric layer on the underlying dielectric layer, the first dielectric layer formed of a first dielectric material; subsequently forming a plurality of slits in the first dielectric layer by etching through the first dielectric layer and stopping on the underlying dielectric layer using an etch that etches the first dielectric layer at a higher rate than the underlying dielectric layer; subsequently depositing a second dielectric material into the plurality of slits to form a plurality of walls of the second dielectric material; subsequently forming an etch mask to define contact hole openings in the first dielectric material in areas between walls; and subsequently etching a plurality of contact holes in the first dielectric layer using a first etch that etches the first dielectric layer at a higher rate than the underlying dielectric layer and stops at the underlying dielectric layer and subsequently using a second etch to extend the plurality of contact holes through the underlying dielectric layer, an individual contact hole formed between a first wall and a second wall of the plurality of walls, the plurality of contact holes etched by a process that provides a higher etch rate of the first dielectric material than the second dielectric material.