Abstract: A self-aligning method and apparatus for magnetically transferring semiconductor chips to corresponding fingers of a conductive lead frame for bonding thereto. A chip having a plurality of soft ferromagnetic integral leads on one face thereof is positioned face up, below overlying soft ferromagnetic fingers of the lead frame. A magnetic field is applied generally perpendicular to the underside of the chip and the fingers to produce lead-finger engagement. While producing this engagement, the chip is concurrently automatically oriented by the magnetic field to precisely align chip leads with corresponding lead frame fingers. In a preferred embodiment, a semiconductor flip chip having soft ferromagnetic contact bumps is placed face up on a tip of a soft iron probe extending from an electromagnet. The probe raises to position the chip into close proximity with the overlying lead frame fingers.

Abstract: A method and apparatus for positioning semiconductor flip chips onto one end of a transfer probe which automatically magnetically aligns the chips with an overlying lead frame structure for bonding thereto. The flip chips are placed into one end of an elongated groove in a positioning apparatus and conveyed between guide rails thereof to successively locate the chips over an opening at the opposite end of the groove. A magnetic force is transmitted through a soft ferromagnetic probe which extends through the opening to engage the back side of the chip thereover. The probe raises the chip from the positioning apparatus and carries it into close proximity with overlying corresponding fingers of a conductive lead frame structure. The magnetic force automatically orients the flip chip contact bumps with their corresponding fingers and simultaneously raises the chip up from the probe into precisely aligned engagement with the lead frame fingers so that it can be bonded thereto.