Enhancing wire bonding capabilities for advanced module assembly
Fig. 1: Butterfly Module without wire bond connection between pins and circuit board.
Fig. 2: Module wire bonder WB300U viewed through the system microscope and coaxial camera, illustrating the visibility issue.
Fig. 3: Successful implementation of wire bond connection from pins to the circuit board using the coaxial camera.
The Mounting and Assembling Department at FBH has extended its wire bonding spectrum. In addition to the existing manual, semi-automatic, and fully automatic wire bonders, a new semi-automatic wire bonder, the “WB 300 U” from UniTemp, has been put into operation. This system offers an innovative solution to challenges arising from visibility restrictions during wire bonding.
In manual and semi-automatic systems, wire bonding is typically monitored through a microscope pitched to a viewing angle of approximately 120°. This allows operators to work ergonomically at the machine and handle most applications without visibility restrictions. Challenges arise, however, when wire bonds need to be placed directly behind tall components, such as in complex modules or behind a housing wall. Fig. 1 illustrates a module where wire bonds must be placed directly behind a housing wall, connecting the pin to the printed circuit board (PCB).
While our fully automatic wire bonders offer both the angled microscope view and a coaxial camera system for wire connections, our existing manual and semi-automatic bonders reach their limits with advanced modules due to the lack of an integrated coaxial view. In practice, however, using a fully automatic system is often neither practical nor efficient for constantly evolving modules in small quantities with frequently changing layouts.
Our new semi-automatic wire bonder combines the advantages of both existing systems. Together with the manufacturer, we further developed and optimized it to meet our specific R&D requirements. The system now allows flexible and rapid wire bonding without the need for time-consuming program creation. With a live image view on a PC screen, precise placement of wire bonds even in areas with visibility restrictions can be assured, which was not possible with our previous manual and semi-automatic systems. Fig. 2 demonstrates the benefit of using a coaxial camera system: with a conventional microscope, wire bonding is not possible because the housing wall obstructs the view of the bonding tool. The coaxial camera, however, enables a direct view of both the pin and the PCB. By aligning the bonding tool with the integrated crosshair – indicating its exact center – wire bonds can be placed with micrometer accuracy. Fig. 3 shows the resulting wire bonds from pin to PCB, successfully executed using this system.
The new capabilities represent a significant advancement for our research and development projects. They allow us to respond more quickly and flexibly to increasingly complex modules with visibility restrictions, further improving the quality and reliability of our results.
This work was supported by the Federal Ministry of Economic Affairs and Climate Action under grant Nr. 50WP1704.