DAP GROUND BOND ENHANCEMENT

摘要

A variety of semiconductor package arrangements and packaging methods are described that improve the reliability of bonding wires that down bond a die to a die attach pad. In one aspect, selected portions of the top surface of a lead frame (which may be in panel form) are plated (e.g., silver plated) to facilitate wire bonding. The plating covers some, but not all of a die attach surface of the die attach pad. In some preferred embodiments, the plating on the die attach pad is arranged as a peripheral ring that surrounds an unplated central region of the die support surface. In other embodiments, the plating on the die attach pad takes the form of bars or other geometric patterns that do not fully cover the die support surface. Unplated portions of the die support surface are roughened to improve the adherence of the die to the die attach pad, thereby reducing the probability of die attach pad delamination and the associated risks to down bonded bonding wires. The described lead frames may be used in a variety of packages. Most commonly, a die is attached to the die support surface of the die attach pad and electrically connected to the lead frame leads by wire bonding as appropriate. At least one of the die's bond pads (typically the ground bond pad(s)) is down bonded to the die attach pad. The die, the bonding wires and at least portions of the lead frame are then typically encapsulated with a plastic encapsulant material while leaving a contact surface of the die attach pad exposed to facilitate electrically coupling the die attach pad to an external device.