Patent ID: 8076181

Claim:
A method for packaging chips comprising: providing a lead frame sheet comprising an array of interconnected lead frames, each lead frame having leads, bottom surfaces of the leads being for bonding to pads of a circuit board; shorting the leads of a first lead frame of the array of interconnected lead frames to a second lead frame of the array of interconnected lead frames by a sacrificial interconnect structure, the sacrificial interconnect structure contacting top surfaces of the leads, wherein the step of shorting the leads together by the sacrificial interconnect structure further comprises shorting the leads to a body of the lead frame sheet by the sacrificial interconnect structure; mounting chips to the lead frames and electrically connecting pads on the chips to corresponding leads; masking at least portions of the bottom surfaces of the leads with a mask; after the step of masking, encapsulating the chips and portions of the lead frame sheet, but not encapsulating the at least portions of the bottom surfaces of the leads; removing the mask; after removing the mask, a first sawing step of sawing through the lead frame sheet along boundaries of the lead frames but not sawing through the sacrificial interconnect structure, the sawing exposing at least a portion of sides of the leads; after the first step of sawing, biasing the lead frame sheet with a bias voltage, wherein the sacrificial interconnect structure couples the bias voltage to the leads of the lead frames; after the step of biasing the lead from sheet with the bias voltage, electroplating exposed bottom and side surfaces of the leads with a solder-wettable metal; after the step of electroplating, a second sawing step of sawing completely thorough the encapsulant and sacrificial interconnect structure to singulate the lead frames and prevent the sacrificial interconnect structure from shorting the leads of the first lead frame to the leads of the second lead frame; and wherein the each lead frame forms a surface mount package, where the leads do not extend beyond a boundary of a lead frame package body.