Handling of ultra-thin dies with fine pitch micro-bumps for advanced packaging applications

The next generation of semiconductor devices is driving advances in packaging to achieve greater miniaturization, improved integration and higher performance. This is also achieved, amongst other technologies, through the use of ultra-thin dies, typically lower than 50μm in thickness. However, the resulting fragility and flexibility of such components, together with increased complexity such as the presence of metal layers and ultra-fine pitch micro-bumps on the device, require specially designed handling solutions which lead to a stable and reliable process that meets the high yield and productivity requirements of high volume manufacturing. Different ejection systems were used and optimized to cater for different die types and wafer carrier tapes. Several design of experiments were carried out, using input parameters such as wafer tape type, ejection system type, die thickness, and bump configuration. The monitored success criteria were throughput, yield and die condition after ejection, in order to determine the most suitable setup for high volume production for a given material set. The experiment results show that stable and reliable picking of ultra-thin dies can be achieved with high throughputs greater than 3000 units per hour, using a variety of ejection technologies. Furthermore, it was also observed that the choice of the wafer tape also plays a major role in the ejection process by virtue of the release mechanism of each specific wafer tape. Several ejection hardware, material and process combinations were found which are able to support high volume manufacturing.