公开(公告)号：US3887997A

公开(公告)日：1975-06-10

申请号：US41427473

申请日：1973-11-09

Applicant: GEN MOTORS CORP

Inventor： HARTLEROAD RONALD J ,  KRAJEWSKI JAMES C ,  RAYON RONALD G

IPC: H01L21/60 ,  H01L21/00 ,  B01J17/00

CPC classification number: H01L21/67144 ,  H01L24/75 ,  H01L2224/75704 ,  H01L2924/01322 ,  H01L2924/14 ,  Y10T29/41 ,  Y10T29/49121 ,  Y10T29/53178 ,  Y10T29/53196 ,  H01L2924/00

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. A magnetic force from the electromagnet is then transmitted through the probe to raise the chip up off the probe and simultaneously rotate it horizontally into precise aligned engagement with the fingers so that it can be bonded thereto.