Chemical mechanical polishing slurry and method for polishing metal/oxide layers

US6294105A · kind A · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Paul M. Feeney · South Burlington, US
• Timothy C. Krywanczyk · South Burlington, US
• Lawrence D. David · Durham, US
• Matthew T. Tiersch · South Burlington, US
• Eric J. White · Vergennes, US

Key dates

• Filing date: Dec 23, 1997
• Grant date: Sep 25, 2001
• Expiry date: Dec 23, 2017

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L21/3212
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

A ferric nitrate-alumina based slurry useful for Chemical-Mechanical-Polishing of tungsten metallurgy and silica based oxides on semiconductor substrates in which the suspension and stability of abrasive material in the slurry is essentially stable. The slurry formulation is balanced to provide low residue of foreign material after polishing and due to its reduced ferric nitrate concentration will be less corrosive than prior art slurries. The recipe for the slurry includes of a 30% wt silica suspension, about 800 ml of 40% by wt ferric nonahydrate and enough 70% wt nitric acid to adjust the pH of the slurry to about 1.2 to 1.4.