The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 19, 2011
Filed:
Oct. 20, 2006
Wolfgang Schmitt, Rodgau, DE;
Christian Loosz, Langenselbold, DE;
Frank Breer, Mespelbrunn, DE;
Jurgen Hornung, Grundau, DE;
Thomas Krebs, Doernsteinbach, DE;
Joerg Trodler, Erlensee, DE;
Wolfgang Schmitt, Rodgau, DE;
Christian Loosz, Langenselbold, DE;
Frank Breer, Mespelbrunn, DE;
Jurgen Hornung, Grundau, DE;
Thomas Krebs, Doernsteinbach, DE;
Joerg Trodler, Erlensee, DE;
W.C. Heraeus GmbH, Hanau, DE;
Abstract
According to the invention, a resin-free solder paste made from a metal powder, particularly soft solder and a gel, is prepared, wherein the gel according to the invention leaves no residue on the metal surface during the remelting of the metal powder. The gel according to the invention is based on a mixture that is stable during storage and that comprises carboxylic acid(s), amine(s), and solvent(s). Important uses are the application of soft solder pastes on power-modules, die-attach, chip-on-board, SiP (System-in-Package), for wafer-bumping, particularly on UBM's (Under-Bump-Metallization), and SMT (Surface Mounted Technology), particularly coated circuits. With the use of resin-free soft solder pastes according to the invention, cleaning is eliminated before a protective coating process after the soldering of an electrical connection, and the formation of pores in solder bumps deposited on UBM's is reduced to less than 20 vol. %.