Patent ID: 8206515

Claim:
A solder composition which is lead-free, which is a cream and is printable, and which has stabilized viscosity and solderability, comprising: a metal powder consisting of a SnZn alloy; and a solder flux consisting of: an epoxy resin; microcapsules consisting of particles of organic carboxylic acid encapsulated with a resin selected from a group consisting of epoxy, polyimide, polycarbonate, polyamide, polyester, polyurea, polyolefin, and polysulfone resins; and a solvent which is a glycol, wherein the presence of the organic carboxylic acid encapsulated with a resin as microcapsules suppresses reactivity of zinc in the SnZn alloy with the organic carboxylic acid so that viscosity and solderability are stabilized.