Browse Prior Art Database

Oxidation Barrier for Multi-Layer Metal-Polyimide Devices

IP.com Disclosure Number: IPCOM000121201D
Original Publication Date: 1991-Jul-01
Included in the Prior Art Database: 2005-Apr-03
Document File: 1 page(s) / 38K

Publishing Venue

IBM

Related People

Shih, DY: AUTHOR [+2]

Abstract

Described is the use of an oxidation barrier layer to improve the interface contact resistance in a multi-layer metal-polyimide devices.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 90% of the total text.

Oxidation Barrier for Multi-Layer Metal-Polyimide Devices

      Described is the use of an oxidation barrier layer to improve
the interface contact resistance in a multi-layer metal-polyimide
devices.

      The utilization of Cr/Cu/Cr as the wiring metallurgy used in
thin film multi-layer circuit board structures has required the
control of both the top and bottom Cr thickness in order to obtain a
good initial contact interface and to survive reliability tests with
minimum degradation.

      The concept described herein is designed to use a thin, but
continuous top Cr, so as to achieve both low initial contact
resistance and to meet stringent reliability tests. However, the thin
Cr layer does not offer a broad process window, especially when
processing larger modules because it requires the use of extended
reactive ion etching (RIE) over-etching to guarantee the opening of
all via contact areas in every layer.  However, the top Cr layer can
be easily sputtered away during RIE with the Cu underlayer exposed to
O2 of CF4/O2 atmosphere at the elevated temperature and becomes
oxidized.  Another concern is with the use of an etch stop layer
which may require two RIE steps to open up the contact area as this
will further narrow down the process window on top of the Cr.

      The concerns can be significantly reduced if we insert a low
contact resistance but high oxidation resistance layer between Cr and
Cu. Therefore, we can achieve the goals of still using t...