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Planar Multilevel Structure Using Polyimide As Interlevel Insulator

IP.com Disclosure Number: IPCOM000035406D
Original Publication Date: 1989-Jul-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Schwartz, GC: AUTHOR

Abstract

A process has been developed which uses polyimide (PI) as an interlevel insulator when constructing structures for semiconductor devices. The procedure alleviates the attack of the lower layer of PI which may otherwise occur during reactive ion etch (RIE) when forming the stencil for the next metal layer.

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Planar Multilevel Structure Using Polyimide As Interlevel Insulator

A process has been developed which uses polyimide (PI) as an interlevel insulator when constructing structures for semiconductor devices. The procedure alleviates the attack of the lower layer of PI which may otherwise occur during reactive ion etch (RIE) when forming the stencil for the next metal layer.

In the polyimide planar process (PPP)[*] a trench occurs around via studs when the subsequent level is processed. RIE of the next PI layer subjects the PI layer below to possible etching. The proposed process serves to eliminate the unintentional etch without the need for a separate masking step.

The suggested process is initiated after the S stud has been embedded in the oxide. For the Metal I level + PI (I), PI is spin- coated and cured which step is followed by the spin coating of an organic release layer which is baked. Plasma- enhanced chemical vapor deposition (PECVD), or a similar process, is used to deposit a barrier layer upon which resist is applied and baked. This level is exposed and developed for the Metal I pattern. RIE steps are used on the barrier, stencil and PI followed by an in-situ sputter clean. Metal I is evaporated into the slots formed above in the PI. A lift-off step removes the stencil.

For stud I + PI (II), a thin coat of PI is applied to fill gaps between Metal I and the walls of the slot in PI (I) and then cured. This is etched back to expose the top of Metal I, and...