| abstract |
A thermally curable adhesive composition that includes a fluxing agent that also acts as an adhesive is provided. The composition includes: (a) a fluxing agent represented by the formula RCOOH, wherein R comprises a moiety having two or more carbon-carbon double bonds wherein in one embodiment, at least one is within an acrylate or methacrylate group, and which may further contain at least one aromatic moiety; (b) optionally, an effective amount of a crosslinkable diluent; (c) optionally, an effective amount of a source of free radical initiators; and (d) optionally, an effective amount of a resin to react with remnant carboxylic acid moieties. By employing an acrylate, methacrylate, or phenol in the structure of the adhesive flux, the cure temperature and moisture absorption characteristics can be significantly improved. The composition can be applied directly onto the surface(s) of devices that are to be joined electrically and mechanically. These devices include, printed circuit substrates, connectors, components, cables, and other electrical devices having metallization patterns to be soldered together by means of a solder-bumped pattern on one or both surfaces. Alternatively, a solder paste, comprising solder powder mixed with the fluxing agent of the present invention can be used. During the reflow step, the fluxing agent promotes wetting of the solder to the metallization patterns and, simultaneously, the fluxing agent itself crosslinks to mechanically bond and encapsulate the surfaces and their metallizations. The compositions can also be used to formulate sinterable conductive inks. |