International Business Machines Corporation

John F Harmuth

John Ulrich Knickerbocker

Krishna Gandhi Sachdev

Glenn A Pomerantz

Candace A Sullivan

Michael E Cropp

Donald W Diangelo

James C Utter

Daniel S Mackin

Bruce E Tripp

David E Speed

David Clifford Long

Jon Alfred Casey

James N Humenik

Robert J Sullivan

John T Butler

Raschid Jose Bezama

Jason Scott Miller

Randall Jason Werner

John P Gauci

Gerald S Andris

Chris T Kapogiannis

An apparatus in which opposed nozzle assemblies are utilized to clean residual material, such as a metallic paste, from an article, such as a screening mask. Each of the nozzle assemblies has a first set of nozzles for spraying a cleaning agent onto the article in a first pattern to first chemically and mechanically remove residual material from the article. At least one of the nozzle assemblies has a second set of nozzles for spraying a cleaning agent onto the article in a second pattern while simultaneously applying a voltage between the second set of nozzles and the article to then chemically and electrolytically remove the remaining residual material from the article.

Apparatus for cleaning residual material from an article

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.

Aqueous quaternary ammonium hydroxide as a screening mask cleaner

A cleaning method and related apparatus for cleaning semiconductor screening masks using an aqueous alkali detergent solution applied under high pressure simultaneously from both sides of the mask, followed by a drying step that uses air knives to blow off the mask surface any residual cleaner solution.

System for cleaning residual paste from a mask

Optimized in-line mask cleaning system

A software asynchronous communication protocol between two computers allows the roles of master and slave to be switched between the computers, depending on the nature and direction of the communication. In order to avoid truncating bit strings transmitted between the computers due to a difference in the write/read cycles of the computers, the software incorporates a dwell to accommodate the slowest computer in the system.

Asynchronous serial communication system for delaying with software

An apparatus and method for screening a pattern of material onto a surface including detection of the instant of separation of the mask from the surface after screening. Particularly as applied to a process for making a multi-layer ceramic device with an automated apparatus, the screening process is speeded by initiating high speed movement immediately when the separation of the mask from the surface is complete. In a preferred embodiment, a shock absorber is used to limit the rate of change of motion of the mask and a sensor is placed directly on a portion of the shock absorber structure. Noise reduction is accomplished through differential sensing and thresholding to improve detection.

Thick film mask separation detection system

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Pleasant Valley, NY, United States of America

John F Harmuth