Abstract: A flip-chip device and process for fabricating the device employs a multilayer encapsulant that includes a first portion encapsulant having a coefficient of thermal expansion of at most 30 ppm/° C. and an elastic modulus of 2-20 GPa and a second portion comprising a polymer flux having a coefficient of thermal expansion that may exceed 30 ppm/° C.

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; (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. 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.

Abstract: A simplified process for flip-chip attachment of a chip to a substrate is provided by pre-coating the chip with an encapsulant underfill material having separate discrete solder columns therein to eliminate the conventional capillary flow underfill process. Such a structure permits incorporation of remeltable layers for rework, test, or repair. It also allows incorporation of electrical redistribution layers. In one aspect, the chip and pre-coated encapsulant are placed at an angle to the substrate and brought into contact with the pre-coated substrate, then the chip and pre-coated encapsulant are pivoted about the first point of contact, expelling any gas therebetween until the solder bumps on the chip are fully in contact with the substrate. There is also provided a flip-chip configuration having a complaint solder/flexible encapsulant understructure that deforms generally laterally with the substrate as the substrate undergoes expansion or contraction.

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) a carboxylic acid neutralizing agent; (c) optionally, a crosslinkable diluent; (d) optionally, a source of free radical initiators; and (e) optionally, a resin. 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.

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; (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. 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.

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.