Patent ID: 7704869

Claim:
A method, comprising: (a) forming an etch stop layer on a top surface of a substrate; (b) forming a first dielectric layer on a top surface of said etch stop layer; (c) forming a profile modulation layer on a top surface of said first dielectric layer; (d) forming a second dielectric layer on a top surface of said profile modulation layer; (e) forming a photo-imaging layer on a top surface of said second dielectric layer; (f) forming an opening in said photo-imaging layer, a region of said top surface of said second dielectric layer exposed in a bottom of said opening; after (a) through (f), (g) performing a first reactive ion etching of said second dielectric layer using a first etch chemistry selective to said profile modulation layer to form an opening through said second dielectric layer; after (g), (h) performing a second reactive ion etching of said profile modulation layer using a second etch chemistry selective to said first and second dielectric layers to extend said opening through said profile modulation layer; after (h), (i) performing a third reactive ion etching of said first dielectric layer using a third etch chemistry selective to said profile modulation layer and selective to said etch stop layer to extend said opening through said first dielectric layer; after (i), (j) performing a fourth reactive ion etching of said etch stop layer using a fourth etch chemistry selective to said first and second dielectric layers to extend said opening through said etch stop layer; and after (j), (k) removing said photo-imaging layer, after said removing said photo-imaging layer, said opening extending from said top surface of said second dielectric layer, through said second dielectric layer, through said profile modulation layer, through said first dielectric layer and through said etch stop layer to said top surface of said substrate.