Confined Laser Heating and the Formation of Bird's Beak-Free Recessed Oxide Isolation
Original Publication Date: 1981-Aug-01
Included in the Prior Art Database: 2005-Feb-12
In order to improve IC packing density and performance, methods of forming "bird's beak"-free recessed oxide isolation (ROI) have long been sought. A laser reflective masking pattern is herein used to confine laser heating to areas where ROI regions are formed. ROI formed by this method is free of or nearly free of the unwanted "bird's beak" structure. The method is as follows: 1. A thin layer 10 of thermal silicon dioxide is first grown on the silicon substrate 11. The layer 10 is then coated with a layer 12 of polyimide, other suitable organic or dielectric film of a desired thickness. A heat treatment may be carried out to increase the layer's thermal stability and surface smoothness. 2.