Aqueous quaternary ammonium hydroxide as a screening mask cleaner

US6351871B1 · kind B1 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Krishna G. Sachdev · Wappingers Falls, US
• John T. Butler · Hopewell Junction, US
• Michael E. Cropp · Lagrangeville, US
• Donald W. DiAngelo · Fishkill, US
• John F. Harmuth · Pleasant Valley, US
• James N. Humenik · Lagrangeville, US
• John U. Knickerbocker · Wappingers Falls, US
• Daniel S. Mackin · Pleasant Valley, US
• Glenn A. Pomerantz · Kerhonkson, US
• David E. Speed · Newtown, US
• Candace A. Sullivan · Pleasant Valley, US
• Bruce E. Tripp · Rhinebeck, US
• James C. Utter · Fishkill, US

Key dates

• Filing date: Jun 17, 1999
• Grant date: Mar 5, 2002
• Expiry date: Jun 17, 2019

Classification

• Technology area (CPC H): Electricity
• CPC primary: H05K2203/122
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

This invention relates to the cleaning of objects that relate to semiconductor printing, such as, for example, screening masks. This invention is basically directed to removing, for example, an organic polymer-metal composite paste from screening masks used in printing conductive metal patterns onto ceramic green sheets in the fabrication of semiconductor packaging substrates. More particularly, this invention is concerned with the automated in-line cleaning of paste screening masks with an aqueous alkaline solution of a quaternary ammonium hydroxide as a more environmentally friendly alternative to non-aqueous organic solvents-based cleaning in screening operations for the production multilayer ceramic (MLC) substrates.