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Improved Adhesion of Multilayered Metallurgies in Semiconduct or Fabrication

IP.com Disclosure Number: IPCOM000074106D
Original Publication Date: 1971-Mar-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 24K

Publishing Venue

IBM

Related People

Beaudouin, PL: AUTHOR [+3]

Abstract

Most metals used in thin-film high-conductivity metallurgies have poor adhesion to dielectric layers used in semiconductor fabrication processes. Where aluminum cannot be utilized, metal such as copper, gold or silver are deposited on a thin layer of chromium to improve the metal dielectric mechanical bond.

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Improved Adhesion of Multilayered Metallurgies in Semiconduct or Fabrication

Most metals used in thin-film high-conductivity metallurgies have poor adhesion to dielectric layers used in semiconductor fabrication processes. Where aluminum cannot be utilized, metal such as copper, gold or silver are deposited on a thin layer of chromium to improve the metal dielectric mechanical bond.

To improve adhesion of chromium or all other high-stress materials used under other metals, the layer of chromium should be kept thinner than 500 angstroms. The bonds between metal and dielectric have a certain mechanical strength which is determined by deposition conditions and substrate cleaning procedures. These bonds must support all the strains which tend to separate the film from its substrate during processing and actual use, plus strains due to the films. The latter are by no means negligible. For an equal thickness, they are two orders of magnitude larger in a chromium layer than in a silver or copper film. Eventually, such strains can be large enough to cause the film to peel from the substrates spontaneously.

The curve shows the force necessary to peel a chromium-copper-chromium layer from a sputtered quartz substrate versus the thickness of the first chromium layer. The curve shows that a decrease in chromium underlayer thickness should greatly increase the mechanical integrity of the chromium-copper bond to a sputtered quartz layer. Thus, where 1000 angstroms of chromium...