Method of encapsulating wire bonds

Abstract

A method encapsulating wire bonds that extend between a die and conductors on a supporting substrate, by contacting an edge of a profiling blade with the encapsulant material to form a bead of the encapsulant on the edge, positioning the edge such that the bead contacts the die and, moving the profiling blade relative to the die to cover the wire bonds with the encapsulant. Wiping the encapsulant over the wire bonds with a profiling blade provides control of the encapsulant front as well as the height of the encapsulant relative to the die. The movement of the profiling surface relative to the die can closely controlled to shape the encapsulant to a desired form. Using the example of a printhead die, the encapsulant can be shaped to present an inclined face rising from the nozzle surface to a high point over the wire bonds. This can be used by the printhead maintenance facilities to maintain contact pressure on the wiping mechanism. However, it will be appreciated that the encapsulant can be shaped to have ridges, gutters, grooves and so on by using a particular shape of profiling blade edge and relative movement with the die.