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Browse Prior Art Database

Doublecoat Planar Polyimide Process

IP.com Disclosure Number: IPCOM000043125D
Original Publication Date: 1984-Jul-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 57K

Publishing Venue

IBM

Related People

Kent, JP: AUTHOR

Abstract

Multilevel metallization is provided on a substrate, such as a semiconductor substrate, by using two thin polyimide insulation coats or layers on a metal pattern to form a smooth, planar insulating surface and then providing vias with a reflow resist technique. As indicated in Fig. 1, a substrate 10 has a first metal pattern 12 formed thereon. A first coat or layer 14 of polyimide is formed over and between the segments of the first metal pattern 12, followed by a second coat or layer 16 of polyimide formed over the first layer 14. It can be seen that the surface of the first polyimide layer 14 will be somewhat uneven or rough, but the surface of the second polyimide layer 16 is smooth and planar. To provide vias through the polyimide layers 14 and 16 to the first metal pattern 12, the reflow resist technique is employed.

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Doublecoat Planar Polyimide Process

Multilevel metallization is provided on a substrate, such as a semiconductor substrate, by using two thin polyimide insulation coats or layers on a metal pattern to form a smooth, planar insulating surface and then providing vias with a reflow resist technique. As indicated in Fig. 1, a substrate 10 has a first metal pattern 12 formed thereon. A first coat or layer 14 of polyimide is formed over and between the segments of the first metal pattern 12, followed by a second coat or layer 16 of polyimide formed over the first layer 14. It can be seen that the surface of the first polyimide layer 14 will be somewhat uneven or rough, but the surface of the second polyimide layer 16 is smooth and planar. To provide vias through the polyimide layers 14 and 16 to the first metal pattern 12, the reflow resist technique is employed. A photoresist layer 18 is formed over the second polyimide layer 16 having openings 20 therein. By baking the photoresist layer 18 at 100-150 C, the slopes at the photoresist openings 20 are drawn into a curved profile, as indicated by the dashed lines 22 in Fig. 2. With these reflow resist vias provided on top of the polyimide layer 16, the photoresist layer 18 and the polyimide layers 14 and 16 are etched, by a reactive ion etch, to form the curved slopes 24 in polyimide layer vias 26, as indicated in Fig. 3. A second metal pattern 28 is then formed on the polyimide layer 16 which is in contact with the firs...