Browse Prior Art Database

PLANAR-STANDARD COMPOSITE OF SPUTTERED SiO2 LAYER FOR ZERO OVERLAP VIA COVERAGE

IP.com Disclosure Number: IPCOM000047054D
Original Publication Date: 1983-Sep-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 67K

Publishing Venue

IBM

Related People

Gajda, JJ: AUTHOR [+3]

Abstract

This is a technique for eliminating leakage paths between the second and third level metallizations in an integrated circuit structure. Logic and memory integrated circuits are designed with several hundred first and second zero overlapped vias (Fig. 1) and terminal vias etched over them. Missing metal or holes in the third level land permit the terminal via etch solution to etch a hole in the second interlay glass (Fig. 2). Subsequent evaporation of the pad metal into the hole causes a leakage path between the third and second level metallizations. A CVD (chemical vapor deposited) or a standard sputtered glass layer has been used for the second interlay glass. Deposition of the standard glass results in poor coverage over the first and second metal composite within a zero overlapped via (Fig. 3).

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 65% of the total text.

Page 1 of 2

PLANAR-STANDARD COMPOSITE OF SPUTTERED SiO2 LAYER FOR ZERO OVERLAP VIA COVERAGE

This is a technique for eliminating leakage paths between the second and third level metallizations in an integrated circuit structure. Logic and memory integrated circuits are designed with several hundred first and second zero overlapped vias (Fig. 1) and terminal vias etched over them. Missing metal or holes in the third level land permit the terminal via etch solution to etch a hole in the second interlay glass (Fig. 2). Subsequent evaporation of the pad metal into the hole causes a leakage path between the third and second level metallizations. A CVD (chemical vapor deposited) or a standard sputtered glass layer has been used for the second interlay glass. Deposition of the standard glass results in poor coverage over the first and second metal composite within a zero overlapped via (Fig. 3). The glass is severely cusped, and the resulting stress produces fissures in the second glass extending down to the second metal. This severe surface geometry, coupled with mouseholes at the via, permits the entrapment of processing contaminants at both levels. The contaminants are transferred between levels through the fissures by capillary action so that the third level Al-Cu metal over the cusp becomes porous from chemical attack (Fig. 4). This technique proposes a change from the single sputtered deposited glass layer to a composite layer comprising a planar glass about 1 mm thick followe...