Chip transfer method and apparatus

Abstract

In a chip transferring apparatus a wafer () and a lead frame () are positioned. A first chip () is picked up from the wafer () by a transfer head (-) in a chip pick-up position, while bonding a second chip to the lead frame () by another transfer head in a chip bonding position. The first chip () is then transferred by said one of the transfer heads from the chip pick-up position to the chip bonding position. Next, the first chip () is bonded on the lead frame () by said one of the transfer heads (-) in the chip bonding position, while another one of the transfer heads picks up a third chip from the wafer () in the chip pick-up position. Each transfer head (-) comprises a collet (-) which, through a mechanical coupling, is coupled to another collet for compensating radial forces exerted on the collet relative to said axis of rotation. Vacuum is transferred to the collet from a stationary pressure source by groove sections () in a transfer assembly stator () communicating through a gap () between the rotatable transfer assembly () and the transfer assembly stator () with gas ducts in the transfer head (-) and the corresponding collet (-). A chip () is picked up from a wafer () by a needle mechanism ().