Abstract: A microelectronic assembly (10) includes an integrated circuit die (12) mounted onto a substrate (14) by solder bump interconnections (32). The die (12) and the substrate (14) are spaced apart by a gap (30) that is filled with a polymeric encapsulant (16). The die (12) includes a die perimeter (24) and a face (27) facing away from the substrate (14). A polymeric reinforcement (18) is disposed onto the die face (27) to protect the die (12) and to reduce the effects of thermally induced stresses on the die (12) and the solder bump interconnections (32). The polymeric reinforcement (18) is spaced apart from the die perimeter (24) to maintain a desired peripheral fillet geometry of the encapsulant (16).

Abstract: A printed circuit board (10) comprises a polymeric coating (30) and a metal circuit trace (26) applied to a substrate (22). The coating defines an opening (32) whereat the substrate is uncoated. The metal circuit trace includes a runner section (28) that is covered by the polymeric coating and a bond pad (20) integrally formed to the runner section at the opening and having an upper surface (40) that includes lip (36) overlying the polymer coating to facilitate positioning of a component for solder bonding to the pad. The bond pad preferably also includes a surface accessible within the opening to enhance solder bonding to the bond pad.

Abstract: An improved encapsulant for an electronic component package is composed of an inorganic powder dispersed in a polycyanurate resin binder. The encapsulant is formed by applying a curing mixture of the powder and a liquid vehicle composed predominantly of a blend of one or more multifunctional cyanate ester compounds that are curable to form the binder. The blend includes a cyanate ester substituted bisphenol derivative compound having the formula ##STR1## wherein R.sub.1 and R.sub.2 are members of the group consisting of hydrogen, methyl and ethyl. Preferably, the blend includes a second cyantophenylene compound having the formula ##STR2## wherein R.sub.3 is a hydrocarbon chain including an aryl link.

Abstract: An improved method is provided for assembling an integrated circuit component to a substrate by a solder bump interconnection that is reinforced by a polymer film. The component is attached to a region of the substrate by a plurality of solder bump interconnections that create a gap between the component interface and the substrate region. A polymer dam is applied to the region encircling the attached component spaced apart therefrom. A liquid polymer precursor material is applied to the region including the gap and is confined by the dam to prevent indiscriminate flow across the substrate. In one aspect of this invention, gas is vented from the gap through a passage in the substrate to enhance fill by the precursor liquid. In another aspect of this invention, the precursor liquid is injected into the gap through a passage in the substrate and spread outwardly therefrom.