Patent ID: 6551863
Filing Date: 2003-04-22
Classification: H01L,Y10T

Abstract:
A method for encapsulating and underfilling a flip chip, the method comprising the steps of:providing a flip chip having projections of conductive material on one side of the flip chip, the projections having a proximate end attached to the flip chip and a distal end opposite the proximate end; immersing the flip chip in a polymer bath, wherein the polymer bath covers the flip chip and part of the projections up to a point between the proximate end of the projection and the distal end of the projection; removing the flip chip from the polymer bath such that a coating of polymer adheres to the flip chip and the part of the projections covered by the polymer bath to form a coated flip chip having the distal ends of the projections uncoated; applying ultraviolet light or heat to the coated flip chip such that an outer layer of the coating cures to form a skin-cured flip chip; placing the skin-cured flip chip on a substrate board to form an assembly; heating the assembly such that: (i) the conductive material forms an electrical junction between the flip chip and the substrate; (ii) the polymer from the polymer coating on the flip chip underfills and encapsulates the flip chip; and, (iii) the polymer from the coating cures.