| 摘要 |
1325016 Welding by pressure WESTERN ELECTRIC CO Inc 6 Oct 1970 [7 Oct 1969] 47392/70 Heading B3R [Also in Division H1] An apparatus for handling beam lead devices comprises a tool having a vacuum pick-up head provided with electrical terminals between which a heating current pulse can be passed. As described the head (Fig. 2) consists of a conductive block 14 of titanium carbide welded between platinum strips 18, 19 which in turn are welded to nickel terminal lugs 20, 21 and is held in a clamp (Fig. 3, not shown). A bore 17 or supply of vacuum and gas under pressure extends through the block to a chamber 14a for the semi-conductor body, the edges 14b of which are rendered insulating by oxidation. In operation an X-Y table carrying a sapphire plate to which the beam lead devices are attached during manufacture by wax is moved to locate a device under the head. The head is lowered to engage the device and heated by a 1 second 100 amp. current pulse to locally melt the wax and tack bond the beam leads to the engaging edges 14b of the head. The applied vacuum helps to hold the device as the head is raised and moved to a testing station. After testing the head carries the device on the instructions of a control circuit linked to the testing circuit either to a reject bin where it is blown off, if defective, or to a bonding or storage station as required. On return of the head to the starting position the XY table is indexed to locate another device beneath it and the process repeated. At the bonding station the head presses the beam leads against conductive tracks on a substrate and a current pulse is passed to effect a bond, which may if desired be consolidated in a further step. In the bonding process the head may be rocked so as to contact the beam leads one at a time. At the storage station devices are pressed into wax on a carrier and the head heated and cooled to fix the device prior to withdrawal of the head, or simply pressed on to a tacky layer on the carrier. At the testing station the beam leads engage printed tracks on a compliant substrate, the tracks in turn engaging fingers connected to the test circuit. |
