Abstract: The invention is an encapsulated circuit assembly including a chip; a substrate; at least one solder joint which spans between the chip and the substrate forming an electrically conductive connection between the chip and the substrate; and an encapsulant formed adjacent the solder joint, wherein the encapsulant comprises a thermoplastic polymer formed by ring opening polymerization of a cyclic oligomer.

Abstract: The invention is an encapsulated circuit assembly including a chip; a substrate; at least one solder joint, wherein the solder joint spans between the chip and the substrate forming an electrically conductive connection between the chip and the substrate; and an encapsulant formed adjacent the solder joint, wherein the encapsulant comprises a hyperbranched polymer formed by the reaction of a monomer of the formula: (A).sub.n RB, wherein A is a coupling group reactive with B, B is a coupling group reactive with A, n is greater than 1, and R is a group selected from the group consisting of an aromatic group, an aliphatic group, and mixtures thereof.

Abstract: A cleavable epoxy resin composition suitable for encapsulating electronic chips and a method for making the composition comprises the cured reaction product of a diepoxide; a cyclic dicarboxylic anhydride curing agent mixture; a 1,3-diaza compound having two nitrogen atoms present with one nitrogen atom doubly bonded to the central carbon and singly bonded to one other carbon, and the other nitrogen atom singly bonded to the central carbon and singly bonded to another carbon and singly bonded to a hydrogen. The 1,3-diaza compound serves either as the sole catalyst or in combination with a tertiary amine catalyst different from the diaza compound. The composition may include an optional hydroxy functional compound capable of reacting with the cyclic anhydrides to form a half ester thereby initiating the reaction between the diepoxide and the cyclic dicarboxylic anhydride curing agent. The resin can be used for the encapsulation of electronic parts, but can be removed by a solvent.

Abstract: A C4 or flip chip reworkable electronic device is provided comprising an integrated circuit chip having conductive pads thereon which pads are electrically connected to corresponding pads on an interconnection substrate by solder connections, wherein the space between the chip and substrate is sealed using a specially defined thermoplastic resin such as polysulfone and polyetherimide.

Abstract: The present invention is an apparatus and method for mixing a plurality of materials in-situ to form an admixture and heating a localized portion of admixture upon dispense. The heat thereby primarily effects the speed of chemical reaction and curing of only the exiting reactants with little effect upon the admixture not dispensed. The apparatus and process are especially useful for encapsulating a plurality of workpieces at a high throughput. Advantageous configurations are described such as wherein the workpieces and/or the dispensing mechanism may be mounted on a carrier and fed by an assembly line. Alternative admixture chemistries are described.

Abstract: Strippable photoimageable compositions are provided that include a cycloaliphatic diepoxide and a photoactive compound. The compositions are especially useful for patterning a substrate.

Abstract: Reworkable encapsulant formulations are being developed to allow recovery of part-good microelectronic assemblies. According to this invention, a gelled form of the solvent is useful for removing the reworkable encapsulant from a specific region of the assemblies without affecting components on the assembly which do not need to be reworked. This novel method eliminates expensive tooling that would otherwise be required to handle the solvent.

Abstract: Structure for mounting electronic devices thereon. The structure is fabricated from a plurality of substrates each having a thermally and/or electrically conductive core surrounded by a dielectric material. The substrates can be adherently placed together with the electrically conductive cores providing ground and power planes or the substrates can be mounted together with connectors electrically interconnecting adjacent substrates and spacing the adjacent substrates apart providing a space through which a fluid can flow to extract heat generated by the electronic devices mounted thereon. The conductive cores provide both power and ground planes to the structure and a means for thermally dissipating the generated heat.

Abstract: Disclosed are charge transfer complexes based on a polyaniline in combination with an organic electron electron acceptor. The resulting conductive polymer possesses enhanced electrical, thermal and solubility properties over known conductive polymers. Also disclosed is a charge transfer based composition of matter whose electrical conductivity, chemical and physical properties are further enhanced by doping with protonic acid. The composition is prepared by a simple method and has widespread application in the printed circuit field, and in various other devices.

Abstract: A C4 or flip chip reworkable electronic device is provided comprising integrated circuit chip having conductive pads thereon which pads are electrically connected to corresponding pads on an interconnection substrate by solder connections, wherein the space between the chip and substrate is sealed using a specially defined thermoplastic resin such as polysulfone and polyetherimide.