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Browse Prior Art Database

Hard on Soft Dielectric for Yield and Reliability Enhancements

IP.com Disclosure Number: IPCOM000109537D
Original Publication Date: 1992-Sep-01
Included in the Prior Art Database: 2005-Mar-24
Document File: 2 page(s) / 81K

Publishing Venue

IBM

Related People

Bergeron, RJ: AUTHOR [+4]

Abstract

By appropriately alternating hard and soft dielectric layers, e.g., silicon nitride or silicon nitride and polyimide, device degradation by process chemicals is avoided and resistance to mechanical damage offered by soft dielectrics is retained. Advantages are illustrated in a film structure which includes a wire bond pad.

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This is the abbreviated version, containing approximately 78% of the total text.

Hard on Soft Dielectric for Yield and Reliability Enhancements

       By appropriately alternating hard and soft dielectric
layers, e.g., silicon nitride or silicon nitride and polyimide,
device degradation by process chemicals is avoided and resistance to
mechanical damage offered by soft dielectrics is retained.
Advantages are illustrated in a film structure which includes a wire
bond pad.

      Referring to the figure, first metal is deposited on insulating
substrate 4 and defined as wiring 2a and wire bond pad 2b by
conventional processing.  Next, hard dielectric 6 is deposited
conformally.  Soft dielectric 8 is deposited and contact holes are
defined by photo masking and etched, stopping on layer 6.  Then,
photoresist is stripped before dielectric 6 is etched to expose metal
2 using dielectric 8 as the etch mask.  Second metal 10 is deposited
and etched to form wiring contacting metal 2a and a final wire bond
pad layer contacting metal 2b.  Then, hard dielectric layer 12 is
conformally deposited.  Next, soft dielectric layer 14, is deposited
and openings are defined and etched over the wire bond pad, using
hard dielectric 12 as an etch stop.  Then, photoresist is stripped
and, using layer 14 as the etch mask, layer 12 is removed to expose
metal 10 at the wire bond pad.

      By using this process, metal surfaces are not exposed to
processing chemicals used in photoresist development and stripping or
those used in etching soft dielectric layers.  ...