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Photoreactive Polyimide Etch-Back Process

IP.com Disclosure Number: IPCOM000059712D
Original Publication Date: 1986-Jan-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Kent, JP: AUTHOR [+2]

Abstract

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 10Πwith respect to the surface of substrate 12. This low angle of incidence minimizes the light penetration into the polyimide region 16 in trench 10.

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Photoreactive Polyimide Etch-Back Process

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 10OE 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. After photoreactive polyimide layer 18 has been exposed, a standard wet etch is used to remove layer 18 with any known laser endpoint detection technique used to monitor the removal of the polyimide. This procedure produces a smooth planar surface, as indicated in Fig. 2. The polyimide in region 16 may now be cured at, e.g., 400OEC. It should be noted, as indicated in Fig. 3, which is a top view of a wafer, that within the plane of the surface of the wafer or substrate 12, beam 20 has a preferred direction of 45OE with respect to the centerline or length of trench
10.

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