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Alternative Materials and Structure of Chemical-Mechanical Polishing Technology for Advanced CMOS Products

IP.com Disclosure Number: IPCOM000113567D
Original Publication Date: 1994-Sep-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 71K

Publishing Venue

IBM

Related People

Aboelfotoh, MO: AUTHOR [+4]

Abstract

Disclosed are materials and structure enabling development of the Damascene chem-mech polishing process for multilevel Al metallization to be used in advanced CMOS devices. This technology eliminates the problems of aluminum chem-mech polishing, via contact resistance, limitations on copper content in the alloy, mass flux divergences at stud/line combinations, and the high stress of tungsten studs. Here the novel properties of copper germanide (Cu[3]Ge) enable the solution of the above problems.

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Alternative Materials and Structure of Chemical-Mechanical Polishing
Technology for Advanced CMOS Products

      Disclosed are materials and structure enabling development of
the Damascene chem-mech polishing process for multilevel Al
metallization to be used in advanced CMOS devices.  This technology
eliminates the problems of aluminum chem-mech polishing, via contact
resistance, limitations on copper content in the alloy, mass flux
divergences at stud/line combinations, and the high stress of
tungsten studs.  Here the novel properties of copper germanide
(Cu[3]Ge) enable the solution of the above problems.

      Copper germanide, formed by either thin film or or chemical
vapor deposition has a very low electrical resistivity (1), excellent
chemical and oxidation resistance, and good adhesion to metals and
silicon oxide.  The material is easily polished by CMP using the
current copper CMP slurry and pads.  Thus Al-alloy lines capped with
this material can be polished, solving the problems of smearing,
corrosion, and pitting associated with aluminum CMP, as well as
metal-RIE problems with Al, especially with high copper content for
electromigration resistance.  Finally, it has been shown (2) that
copper readily diffuses through Cu[3]Ge, thus lines and studs could
be capped while still allowing copper flow to maintain
electromigration hardness of the stud/line combination, in contrast
to tungsten stud/aluminum line structures.

      The new CMP structure/p...