Browse Prior Art Database

Nitride/Polyimide Isolation Enhancement

IP.com Disclosure Number: IPCOM000043561D
Original Publication Date: 1984-Sep-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Leipold, WC: AUTHOR [+3]

Abstract

In this enhanced process for fabricating dual-dielectric nitride/polyimide passivated IGFET devices the silicon nitride layer is made much thinner than it is in conventional devices of this type and is entirely covered by a thin polyimide layer that is formed prior to the formation of the usual thicker polyimide layer, which only partially overlies the nitride layer. The composite nitride/polyimide layer is much less susceptible to stress cracking and the effects of pinholes, cusps and foreign materials than the conventional thicker nitride layer. The occurrence of metal-to-metal vertical shorts and the amount of interlevel metal-to-metal capacitance are greatly reduced. The structures produced by the old and new processes are contrasted in Figs. 1 and 2.

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Nitride/Polyimide Isolation Enhancement

In this enhanced process for fabricating dual-dielectric nitride/polyimide passivated IGFET devices the silicon nitride layer is made much thinner than it is in conventional devices of this type and is entirely covered by a thin polyimide layer that is formed prior to the formation of the usual thicker polyimide layer, which only partially overlies the nitride layer. The composite nitride/polyimide layer is much less susceptible to stress cracking and the effects of pinholes, cusps and foreign materials than the conventional thicker nitride layer. The occurrence of metal-to-metal vertical shorts and the amount of interlevel metal-to-metal capacitance are greatly reduced. The structures produced by the old and new processes are contrasted in Figs. 1 and 2. The new process can be implemented without extra masking steps inasmuch as the composite nitride/polyimide layer can be etched by reactive ion etching (RIE) in a single step. The thin nitride layer is less subject to cracking caused by internal stress, and any pinholes, cusps and foreign materials in it are covered by the overlying thin polyimide layer. Production yield is greatly improved because of this. Interlevel metal-to-metal capacitance is reduced, and vertical short circuits occur with far less frequency. The detailed steps of the enhanced process are listed below: Apply and define first-level metal 1. 1. Deposit 0.32 micron of silicon nitride 2. 2. Apply adhesion...