Browse Prior Art Database

Via Holes in Quartz Coatings

IP.com Disclosure Number: IPCOM000088025D
Original Publication Date: 1977-Apr-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 49K

Publishing Venue

IBM

Related People

Sarkary, HG: AUTHOR [+2]

Abstract

Zero overlap vias on planarized quartz is a significant requirement for current high-density, multilevel metallurgy LSI (large-scale integration) circuits.

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

Via Holes in Quartz Coatings

Zero overlap vias on planarized quartz is a significant requirement for current high-density, multilevel metallurgy LSI (large-scale integration) circuits.

To achieve a total planarization of quartz without any step or peak, over a 200 micro-inch metal land width and 9500 angstroms of metal thickness, with about 24,000 angstroms of sputtered quartz, is almost impossible.

Today's sputtering processes leave a peak height of quartz of about 4000 angstroms - 8000 angstroms depending upon metal and quartz thickness variation.

As shown in Figs. 1 and 2, the conventional design of a crossover or "T" has disadvantages as quartz results in a high "peak" or "step" and, as such, to open via, a considerable over-etching is required, which inadvertently over-etches the regular vias on 200 micro-inch single land patterns to an extent that there is a metal-to-metal short.

The approach herein is directed to a circuit layout design to overcome the problems depicted in Figs. 1 and 2. The main feature of this new design is to avoid opening of via holes, as conventionally done, directly over the metallization. Figs. 1 and 2 show these prior positions of the vias over the underlying pattern.

The present method eliminates these problems because of the first-level metal design considerations. The whole metal pattern layout comprises a via access layout which leaves a break in the continuity of the metal pattern, which is to be connected during second-level...