Flux composition and soldering method for high density arrays

• Main Authors: Henderson, Donald, Bernier, William, Spalik, James
• Format: Patent
• Language: English
• Published: 30.05.2002

The invention is a single phase flux composition suitable for use with high density arrays, that comprises dicarboxylic acid in an amount sufficient to react with the oxidized surface area in a high-density array, a first organic solvent, and a second organic solvent having a higher evaporation temperature than that of said first organic solvent. Preferred dicarboxylic acids are adipic, pimelic, suberic, azelaic and sebacic acids. Preferably, the composition comprises greater than 6% dicarboxylic acid, more preferably greater that 6% to about 15%, and even more preferably from about 8% to about 10% of the dicarboxylic acid. Preferred amounts of the first organic solvent are in the range of from about 25% to about 75% by weight and preferred amounts of the second organic solvent are from about 10% to about 35% by weight. Preferably, the ratio of the first organic solvent to the second organic solvent is about 3:1. The invention is also a method for using the inventive composition to solder high density arrays which, for eutectic lead/tin solder, involves heating at extended dwell times and high temperature relative to typical compositions.