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Via Rich Thin Film Wiring Scheme for Electronic Packaging

IP.com Disclosure Number: IPCOM000108236D
Original Publication Date: 1992-May-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 2 page(s) / 91K

Publishing Venue

IBM

Related People

Luethje, SB: AUTHOR [+2]

Abstract

Disclosed is a wiring scheme for multilevel thin film technologies which doubles the number of via connections between levels, loosens alignment tolerances, and maintains wiring density. In these structures the new wiring scheme creates a sufficient number of vias to wire high density structures (3 lines per channel).

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Via Rich Thin Film Wiring Scheme for Electronic Packaging

       Disclosed is a wiring scheme for multilevel thin film
technologies which doubles the number of via connections between
levels, loosens alignment tolerances, and maintains wiring density.
In these structures the new wiring scheme creates a sufficient number
of vias to wire high density structures (3 lines per channel).

      Typical circuitry designs for multilevel thin film structures
consist of running multiple parallel lines between vias placed in a
straight orthogonal array.  In the 3 lines per channel design (Fig.
1) there are three unit length lines and one via per unit cell.
Wirability vias, additional vias within the array, must be small and
connect directly into lines.  The equipment for making the small vias
with tight alignment tolerances ( 0.5 micron) is complex and
costly.

      The thin film wiring scheme shown in Fig. 2 has much better
utilization of the wiring space.  An additional via is added at the
center of the unit cell and lines are placed diagonally with respect
to the original via grid.  In the new unit cell there are 2.8 unit
lengths of wiring compared to 3 unit lengths in the typical design.
However, there are now 2 vias per unit cell, double the via density
of the original design.  The new via position at the center of the
cell replaces the small wirability via in the original design.  This
new wirability via is larger in size which allows looser level to
level al...