Partially patterned lead frames and methods of making and using the same in semiconductor packaging

Abstract

A method of making a lead frame and a partially patterned lead frame package with near-chip scale packaging (CSP) lead-counts is disclosed, wherein the method lends itself to better automation of the manufacturing line as well as to improving the quality and reliability of the packages produced therefrom. This is accomplished by performing a major portion of the manufacturing process steps with a partially patterned strip of metal formed into a web-like lead frame on one side, in contrast with the conventional fully etched stencil-like lead frames, so that the web-like lead frame, which is solid and flat on the other side is also rigid mechanically and robust thermally to perform without distortion or deformation during the chip-attach and wire bond processes, both at the chip level and the package level. The bottom side of the metal lead frame is patterned to isolate the chip-pad and the wire bond contacts only after the front side, including the chip and wires, is hermetically sealed with an encapsulant. The resultant package being electrically isolated enables strip testing and reliable singulation without having to cut into any additional metal. The use of the instant partially patterned lead frame in making ELP, ELPF and ELGA-type CSPs is also disclosed.