Browse Prior Art Database

Self-Aligned Double-Layer Insulator Process

IP.com Disclosure Number: IPCOM000100008D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2005-Mar-15
Document File: 3 page(s) / 66K

Publishing Venue

IBM

Related People

Koblinger, O: AUTHOR

Abstract

This invention concerns a double-layer insulation for multilayer wirings, wherein an organic insulator is arranged underneath an inorganic one. Metal is deposited on this double-layer insulation. It is essential for the structured metal lines to be used as an etch mask to remove the inorganic insulation from areas not covered by metal. This eliminates problems, such as blistering, cracking, etc., which occur in covered organic layers.

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Self-Aligned Double-Layer Insulator Process

       This invention concerns a double-layer insulation for
multilayer wirings, wherein an organic insulator is arranged
underneath an inorganic one.  Metal is deposited on this double-layer
insulation.  It is essential for the structured metal lines to be
used as an etch mask to remove the inorganic insulation from areas
not covered by metal.  This eliminates problems, such as blistering,
cracking, etc., which occur in covered organic layers.

      Example Compared with the state of the art, the second
inorganic insulator, for example, nitride, is applied to the second
polyimide (underlying the third metal) (Fig. 1A).  In the subsequent
via etch step for the metal-2/metal-3 connections, the double-layer
insulation nitride/ polyimide is etched in a single-mask step (Fig.
1B).  Etching is effected such that a steep resist mask produces a
flattened profile of the vias through both insulation layers, so that
the via dimensions are readily controllable.  Another advantage is
that the polyimide is preplanarized, so that the structure of the
nitride shows only slightly on top of the underlying metal line.

      Upon completion of via etching, the third metallization is
applied either by lift-off technique or dry etching. During the
subsequent definition of the metal lines by dry etching, the nitride
acts as an etch stop (Fig. 1C).  The nitride is removed immediately
afterwards in a further dry etch step (Fig. 1D)....