METHOD OF PRINTED CIRCUIT BOARD HOLD DOWN FOR WIREBONDING AND DISPENSING

MOTOROLA INC. Technical Developments Volume Ia March 1993

Ml3HOD OF PRINTED CIRCUIT BOARD HObD DOWN FOR WIREBONDING AND DISPENSING

by Marc Papageorge, &idiu Neiconi and Kenneth Wasko

BACKGROUND

  In the past, manual workholders to hold down ceramic substrates for wirebonding has shown to be ben- eficial to obtain proper wirebonding results. Improving on prior art, a new flexible workholder was developed for various types of PCB substrates. The PC board arrays, used for glob top chip carriers, have different routing patterns due to the chip carrier size. The past workholders were not flexible to remove and accommodate the vari- ous arrays used during processing. This publication will describe a new technique in obtaining a flexible workholder that can be used with various routed arrays, providing increased reliability in wirebond integrity and reducing change over time.

DESCRlPTlON

The flexible work holder contains a heater block, hold down clamps, vacuum plates, and release clamps

(See Figure). The heater iblock is integrated with the workholder that remains on the wirebonder. The heater block contains a vacuum port that mates with various vacuum plates that are d&&d with vacuum holes under each chip carrier site on the array. These thin vacuum plates (0.250 inches) allows quick change overtime with- out removing the entire w&holder. The vacuum plates are sealed with an O-rink and screws. For additional array stability and accuracy hold down clamps and guide pins a...