BONDING ELECTRICAL LEADS.

摘要

1,238,335. Welding by fusion. WESTERN ELECTRIC CO. Inc. 27 Aug., 1968 [31 Aug., 1967], No. 40922/68. Heading B3R. [Also in Divisions G2 and H1] In a method of bonding electrical leads 21 extending from a workpiece to other leads 73, a beam of electromagnetic wave radiant energy is shaped with a pattern extending over the lead portions only at the locations to be bonded, the locations being external of the workpiece, and said pattern is applied simultaneously to said lead portions to effect bonding. In welding a plurality of leads 21 of a semi-conductor device to areas 73 on a substrate, a collimated energy beam 33 is shaped into four lines 24 circumscribing the perimeter of the body of the device, whereby the energy is focused and concentrated simultaneously only on the regions to be welded. The beam may be so shaped to any desired configuration using a lens 26 which comprises a member of cylindrical portions 31 each of which brings energy incident upon it to a line focus. The desired configurations may be, e.g. square, rectangular, triangular or polygonal. The cylindrical portions may be mutually spaced so that the desired configuration of the beam on the workpiece will be discontinuous, and in such cases a mask or masks may be used to prevent damage to the work or device by the non-focused parts of the beam. The size of the desired configuration of the beam on the workpiece may, for a given lens, be altered by the use of spherical lenses arranged between the lens 26 and the work to reduce or magnify the focused beam. The workpiece may be correctly positioned below the apparatus, and subsequently monitored, by closed circuit TV. In another embodiment (Fig. 10, not shown), the composite lens 26 is replaced by a mask (82) which shapes, but does not focus, the beam. The apparatus (Fig. 7) includes a rotatable holder 63 containing a number of different shapes of cylindrical lenses 26 any one of which may be selected for a particular application, and a further rotatable holder 61 carrying different lenses for altering the size of the desired configuration of the beam on the workpiece. The beam 33 may originate from a laser or from sources of infra-red or ultra-violet, or an incandescent arc or plasma source may be used.