Photoreactive Polyimide Etch-Back Process
Original Publication Date: 1986-Jan-01
Included in the Prior Art Database: 2005-Mar-08
To provide a planar surface on a wafer or chip having polyimide-filled trenches, photoreactive polyimide disposed on the surface of the wafer is exposed at a shallow angle of 1 to 10 degrees. As indicated in Fig. 1, a trench 10 is formed in a semiconductor substrate 12 with photoreactive polyimide 14 deposited over substrate 12. A region 16 of polyimide 14 fills trench 10 and a region 18 of polyimide 14 forms a layer over the surface of substrate 12. Polyimide layer 18 is exposed with a grazing incidence light beam 20 having an angle of 1 to 10Œ with respect to the surface of substrate 12. This low angle of incidence minimizes the light penetration into the polyimide region 16 in trench 10.