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Test for Determining Amount of Large Conductive Metal Particles in Screening Pastes

IP.com Disclosure Number: IPCOM000046049D
Original Publication Date: 1983-May-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Leung, WC: AUTHOR

Abstract

This flow test will determine whether or not abnormally large amounts of platelets and other large conductive metal particles are present in a sample of screening paste. The flow test measures the degree of clogging of a screen by particles in a paste solution while the solution is forced through the screen by its own weight.

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Test for Determining Amount of Large Conductive Metal Particles in Screening Pastes

This flow test will determine whether or not abnormally large amounts of platelets and other large conductive metal particles are present in a sample of screening paste. The flow test measures the degree of clogging of a screen by particles in a paste solution while the solution is forced through the screen by its own weight.

In the semiconductor packaging technology, and in particular the fabrication of multilayer ceramic substrates, conductive circuit patterns are deposited on substrates or green ceramic sheets by screening a conductive paste through a screen. As the packages become more sophisticated and dense, the screening patterns, and particularly the via holes and line widths, are becoming increasingly smaller. Difficulty is experienced when screening metal conductive paste containing platelets and other large particles because the masks become clogged, open and unfilled vias result, producing pattern voids and poor definition in the metallurgy.

In this flow test, the conductive paste to be analyzed is first dissolved in a solvent system, typically methyl alcohol and TEXANOL* or perchlorylethylene, and then allowed to flow through a small porous medium screen. The apparatus consists of a separatory funnel 10, a screen holder 12, a screen 14 typically a 170-mesh screen, a graduated cylinder 16, and a stop watch. About 15 grams of the paste to be analyzed are dissolved in 16...