Patent ID: 8003428
Filing Date: 2011-08-23
Classification: H01L

Abstract:
1. A method of forming a semiconductor structure comprising: forming a silicon oxide layer on top of a metal interconnect structure; forming at least one metal structure having a top surface that is coplanar with a topmost surface of said silicon oxide layer within said silicon oxide layer; applying a positive tone photoresist on said silicon oxide layer; exposing said positive tone photoresist under a defocused illumination condition; developing said positive tone photoresist, wherein said positive tone resist has a continuous and concave profile in an exposed area after development; transferring said profile into said silicon oxide layer to form a concave cavity in said silicon oxide layer; and forming a flat-top convex-bottom lens comprising a dielectric material in said concave cavity, wherein a bottommost surface of said flat-top convex-bottom lens is located below a level of said topmost surface of said silicon oxide layer.