Browse Prior Art Database

Enhancement of Sputtered Vias

IP.com Disclosure Number: IPCOM000120299D
Original Publication Date: 1991-Mar-01
Included in the Prior Art Database: 2005-Apr-02
Document File: 1 page(s) / 35K

Publishing Venue

IBM

Related People

Anschel, M: AUTHOR [+4]

Abstract

Disclosed is a method to enhance electrical stability and reliability of vias used in MCP-type products. The method involves an annealing treatment of sputtered chromium and copper metallization.

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Enhancement of Sputtered Vias

      Disclosed is a method to enhance electrical stability and
reliability of vias used in MCP-type products.  The method involves
an annealing treatment of sputtered chromium and copper
metallization.

      Sputtered metallization contains more oxygen than evaporated
metallization due to distinctive features of both processes.  The
higher oxygen content of sputtered product produces high resistance
vias that are more sensitive to temperature and humidity stressing
(85oC at 80% humidity).

      An annealing treatment in forming gas (90% nitrogen and 10%
hydrogen) or in pure hydrogen at about 400oC, for about 45 to 60
minutes, reduces drift of sputtered vias.  A 35% improvement in via
resistance stability has been demonstrated after temperature and
humidity stressing for 500 hours.

      The annealing process is believed to reduce oxides at the Cr/Cu
interface and may also reduce residual organic contamination from
previous processes.  Also, annealing promotes diffusion of chromium
into the copper grain boundaries and at the via interfaces.  It is
also believed that these interfaces become less porous, and with
reduced oxygen content, the probability of moisture diffusion into
the interface is reduced.  This results in enhanced via resistivity
and reliability.

      Disclosed anonymously.