Browse Prior Art Database

Selective Chemical-Mechanical Polishing Process for Removal of Copper

IP.com Disclosure Number: IPCOM000103862D
Original Publication Date: 1993-Feb-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Carr, JW: AUTHOR [+2]

Abstract

Disclosed is a general method for combining fast chemical mechanical removal of Copper films with low removal rates of underlying semiconductor films to facilitate achieving endpoint. The approach is to use known Copper passivants, such as the azoles to form a thin but soft protective layer selectively on the Copper but not on the underlying insulating films. This concept allows removal rates of the Copper during Chemical-Mechanical Polishing (CMP), where the protective layers are continuously reformed, to be maximized while removal rates ofthe underlying films are minimal, thus resulting in high etch rate ratios.

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Selective Chemical-Mechanical Polishing Process for Removal of Copper

      Disclosed is a general method for combining fast chemical
mechanical removal of Copper films with low removal rates of
underlying semiconductor films to facilitate achieving endpoint.  The
approach is to use known Copper passivants, such as the azoles to
form a thin but soft protective layer selectively on the Copper but
not on the underlying insulating films.  This concept allows removal
rates of the Copper during Chemical-Mechanical Polishing (CMP), where
the protective layers are continuously reformed, to be maximized
while removal rates ofthe underlying films are minimal, thus
resulting in high etch rate ratios.

      Prior art references include a chem mech polish process for
Nickel in which the continuous formation of a passivating oxide
surface layer [1]  on the metal is thought to be the process
mechanism.  In addition, Benzotriazole is disclosed in [2]  as an
additive for mechanical polishing of Copper to prevent the surface
from oxidizing.  Finally, Benzotriazole, in the presence of an acid
aqueous solution of peroxide, is disclosed in [3]  as a chemical
surface treatment for Cu yielding superior surface quality.  In none
of the prior art was there disclosed a method similar to that of the
present invention.

      Properties of Cu surface modified layers important in the
present invention include the following:  Rapid formation, thickness
less than 100nm, provides ex...