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Selective Metal Deposition by a Resistless Liftoff Process

IP.com Disclosure Number: IPCOM000038762D
Original Publication Date: 1987-Mar-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Maier, WF: AUTHOR [+3]

Abstract

There are many steps in microelectronic device processing when the selective deposition of metals becomes a critical limiting issue.

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Selective Metal Deposition by a Resistless Liftoff Process

There are many steps in microelectronic device processing when the selective deposition of metals becomes a critical limiting issue.

Selectivity is generally very difficult to achieve, always requiring special approaches. For example, a laser can be used to initiate growth in a selected area. Another method is to carefully control process variables so as to maximize nucleation in one area (e.g., silicon oxide). Very often, blanket metal depositions combined with lithography and liftoff steps are necessary to achieve the desired metal pattern. A simple and inexpensive method to carry out selective metal deposition is described herein. Many metals (Pd, Ni, Fe, V, Nb, Ta, Ti, Mn, Ag, Lu, Er, and their alloys, among others) are known to undergo lattice expansion in the presence of hydrogen due to the facile diffusion of hydrogen into the bulk metal and the formation of a hydride phase. This lattice expansion is used to selectively break weaker metalsubstrate interactions (like those to oxides and other nonmetallic materials), while strong interactions such as metalmetal or metalsemiconductor (e.g., formation of a metal silicide) remain intact and unaffected. This technique, which is a very general one, is demonstrated by selectively depositing metal onto a pattern of etched holes in silicon dioxide films on silicon wafers. As an example, a thin palladium film (25 nm) is deposited by evaporation onto a patterned SiO...