Browse Prior Art Database

Self Aligned Contact Holes

IP.com Disclosure Number: IPCOM000048542D
Original Publication Date: 1982-Feb-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Betz, PW: AUTHOR [+4]

Abstract

To provide interlevel metal contact holes, a raised portion of a first level metal is provided and covered with an insulating layer, such as polyimide, and then the insulating layer is etched until the upper surface of the raised portion of the first level metal is exposed, resulting in a self-aligned contact via.

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Self Aligned Contact Holes

To provide interlevel metal contact holes, a raised portion of a first level metal is provided and covered with an insulating layer, such as polyimide, and then the insulating layer is etched until the upper surface of the raised portion of the first level metal is exposed, resulting in a self-aligned contact via.

A riser-type element 10, shown in Fig. 1 and in cross-sectional views in Figs. 2 and 3, which may be made of a self-passivating material such as silicon or aluminum. or of an insulating material, is formed on a silicon substrate 12 by employing lift-off techniques. If desired, a hardened photoresist may be formed as element 10 defined by conventional photo-printing techniques. A first level metal is then deposited, e.g., by again using lift-off techniques, over the surface of the structure to form first and second metal strips 14 and 16, with metal strip 16 overlapping at least a portion of element 10. After metal strips 14 and 16 are formed, the structure is covered with a layer of silicon nitride 18, followed by a cured layer of planar polyimide 20, as indicated in Fig. 2.

An interlevel via mask (not shown) is then placed over polyimide layer 20 with an opening therein roughly aligned over the riser-type element 10 and the polyimide layer 20 is etched by, e.g., using reactive ion etching techniques to expose only the silicon nitride 18 located on metal strip 16 over element 10. The exposed silicon nitride 18 is etched with a...