Browse Prior Art Database

Polyimide Layers Having Tapered Via Holes

IP.com Disclosure Number: IPCOM000089055D
Original Publication Date: 1977-Sep-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Hitchner, JE: AUTHOR [+2]

Abstract

Polyimide is a substitute for quartz as the insulating material on semiconductors requiring multiple levels of metallization. To reduce defects, it is desirable that the via holes in the polyimide be tapered rather than steep-walled. Tapering assures adequate continuity of the subsequently deposited metallization within and around the via holes.

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Polyimide Layers Having Tapered Via Holes

Polyimide is a substitute for quartz as the insulating material on semiconductors requiring multiple levels of metallization. To reduce defects, it is desirable that the via holes in the polyimide be tapered rather than steep-walled. Tapering assures adequate continuity of the subsequently deposited metallization within and around the via holes.

Referring to the figures, tapered via holes in polyimide are formed as follows: First, coat the underlay 2 with polyimide 4. After adequate baking, apply a coat of photoresist 5. The via pattern is formed with normal exposure and development techniques, as shown in Fig. 1. The wafer is etched in oxygen plasma in a reactive ion etcher. Because the photoresist mask is etched simultaneously with the polyimide, a tapered via hole 3 is formed. After completing the etching of polyimide 4, the remaining photoresist 5 may be removed by standard wet processing.

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