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ACIDIC/ALKALINE DIAMOND SLURRY FOR USE IN CHEMCIAL / MECHANICAL PLANARIZATION OF SEMI-CONDUCTOR WAFERS

IP.com Disclosure Number: IPCOM000010026D
Publication Date: 2002-Oct-09
Document File: 3 page(s) / 31K

Publishing Venue

The IP.com Prior Art Database

Abstract

A stable, well-dispersed suspension formulation comprising diamond micron powder with a specially formulated mixture of water and organic compounds for use in lapping applications for semiconductor wafers / the chemical mechanical planarization of semiconductor circuits, for superior removal rates and surface finishes relative to the currently available silicon and alumina slurries.

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ACIDIC/ALKALINE DIAMOND SLURRY FOR USE IN CHEMCIAL / MECHANICAL PLANARIZATION OF SEMI-CONDUCTOR WAFERS

 

BACKGROUND

        � � � � � � � � � � � Current CMP technology utilizes silica and alumina based slurries in high solids concentrations.� Diamond particles are much harder than those used in existing slurries.� Because of the increased hardness, the corresponding slurries will result in improved material removal rates and surface finishes of the semi-conductor wafer.

        � � � � � � � � � � � There is a need for new slurries comprising diamond micron powder, organic additives, and water to be used in the chemical / mechanical planarization of integrated circuit wafers.� �

        � � � � � � � � � � � We have found that the use of diamond micron powder in the slurry provides superior removal rates and surface finishes relative to the currently available silicon and alumina slurries.� Typically, diamond suspension under acidic conditions is not stable.� The organic additives stabilize the diamond dispersion and prevent the formation of diamond aggregates which cause scratches in the IC / semiconductor wafer.� This helps improve process cycle times and surface finish of semi-conductor wafers.

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DETAILED DESCRIPTION

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        � � � � � � � � � � � In this paper, we will describe the process wherein diamond powder is combined with a specially formulated mixture of water and organic compounds to produce a stable, well-dispersed suspension.� When used in lapping applications for semiconductor wafers, this formulation will result in superior lapping rates and surface finishes.

        � � � � � � � � � � � The new slurry formulations contain diamond micron powder, two non-ionic surfactants (one water soluble component, preferable polyethylene oxide sorbitan monolaurate and one oil soluble component, preferable sorbitan monooleate), and one polyglycol (preferably low molecular weight polypropylene glycol).� The formulation also includes a polymeric component (preferably ethylene oxide propylene oxide block copolymer) for better control of wettability.� The pH is adjusted with small amounts of acetic acid.� The invention produces a dispersible diamond slurry formulation with improved stability against aggregation and separation and ease of dispersibility.� It further increases stability against aggregation during storage after dilution with water.� � �

        � � � � � � � � � � � The diamond powder used is less than 5 microns in size with a mean size less than 1 micron.� The weight percent of diamond in the dilute slurry is between 0.1% and 5%.� The pH of the dilute slurry is between 8 and 12.

        � � � � � � � � � � � EXPERIMENTS.� � In the following experiment, the preparation of the slurry involved four main steps:

a)                 preparation of the surfactant composition

b)                 dispersion of the diamond particles in the liquid

c)                  dilution of the concentrated suspens...