Patent attributes
A method of applying encapsulant to a die mounted to a support structure by providing a die mounted to the support structure, the die having a back surface in contact with the support structure and an active surface opposing the back surface, the active surface having electrical contact pads, positioning a barrier proximate the electrical contact pads and spaced from the active surface to define a gap and, depositing a bead of encapsulant onto the electrical contact pads such that one side of the bead contacts the barrier and a portion of the bead extends into the gap and onto the active surface. Placing a barrier over the active surface so that it defines a narrow gap allows the geometry of the encapsulant front (the line of contact between the encapsulant and the active surface) can be more closely controlled. Any variation in the flowrate of encapsulant from the needle tends to cause bulges or valleys in the height of the bead and or the PCB side of the bead. The fluidic resistance generated by the gap between the barrier and the active surface means that the amount of encapsulant that flows into the gap and onto the active surface is almost constant. The reduced flow variations make the encapsulant front closely correspond to the shape of the barrier. Greater control of the encapsulant front allows the functional elements of the active surface of the die to be closer to the contact pads.
