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:
Nov. 23, 1999
Filed:
Sep. 15, 1997
Joram Diamant, Moraga, CA (US);
Henry L Myers, San Jose, CA (US);
Sophia Systems Co., Ltd., Tokyo, JP;
Abstract
A polymer-based solder paste composition having the strength and corrosion resistance of joints produced by conventional solder technology and the environmental and processing advantages of ICA technology comprises a powdered solder metal with a single component (single package) polymerizable flux composition. In one embodiment the polymerizable flux composition includes 55-70% by weight of an epoxy such as epoxy novolac, the diglycidyl ethers of bisphenol A and F, and mixtures thereof, 0-15% by weight of a dicarboxylic acid, 3-5% by weight of an amine thermal curing agent, and the balance may include a polyalcohol, a chelating agent, a defoamer, a thixotrope and a surfactant. In another embodiment the polymerizable flux composition includes approximately 55-70% by weight of an epoxy such as trifunctional epoxide of p-aminophenol, approximately 20-30% by weight of a liquid organic acid such as a carboxy-acrylate, and approximately 4-10% by weight of an amine thermal curing agent. Organic solvents such as linear hydrocarbons and esters of lactic acid may be added to decrease the viscosity as necessary. Upon heating, the solder metal spontaneously segregates from the flux composition, fuses, and forms a metallurgical joint, while the single-component polymerizable flux composition encapsulates the fused metal in a polymer coating which remains firm but pliable at reflow temperatures.