Indexer PVD platform — The key enabler for high productivity and low contact resistance for next-generation WLP applications

This work analyzes the key performance of two different multi-chamber PVD systems used in volume WLP manufacturing. These are the Cluster-type and the Indexer-type platforms, respectively. It is emphasized how the faster wafer handling, which is a unique characteristic of the Indexer concept, results in throughput of production flows exceeding 50 wafers/hour. Moreover, the strategies of degas, cooling and sputter-etch implemented in the process-of-records executed by Indexer allow for wafer processing at lower temperature regimes and result in 50% lower contact resistance baseline. This work reports Rc values well below 1.0 mOhm measured on single-contact Kelvin structures. The Indexer system presented promotes itself as the ideal high-productivity PVD platform capable to tackle the ever-increasing manufacturing challenges arising from the progressive shrinkage of the critical device dimensions of next-generation WLCSP and FOWLP.