Abstract: A solution (20) is dispensed onto bond pads (18) on a substrate (14). An integrated circuit component (12) that includes solder bumps (16) formed on component bond pads (30) is superposed onto the substrate (14) such that the solder bumps (16) rest against the bond pads (18). The solution (20) includes an anhydride compound that acts as a fluxing agent. The subassembly (11) is heated to a temperature sufficient to bond the solder bumps (16) to the bond pads (18) to form solder bump interconnections (26). During the bonding process, the fluxing agent substantially vaporizes and leaves virtually no residue on the substrate (14) to allow the component (12) to be effectively underfilled with a polymeric encapsulant (24).

Abstract: A microelectronic assembly (10) includes an integrated circuit die (12) mounted onto a substrate (14) and spaced apart by a gap (30). Solder bump interconnections (32) extend across the gap (30) and physically attach and electrically connect an electrical circuit on the substrate (14) to an electrical circuit on the integrated circuit die (12). The gap (30) is filled with a transparent encapsulant (16) to protect the solder bump interconnections (32). The transparent encapsulant (16) is composed of a polymeric matrix and filler particles dispersed in the matrix. The polymeric matrix and the filler particles have substantially similar indices of refraction, thereby making the encapsulant (16) transparent. The integrated circuit die (12) includes light emitting diodes (18) that transmit light toward the transparent substrate (14) to form a display.