However, in order to ensure the yield rates of the new fingerprint sensors, TSMC is also expected to handle the backend wafer level-chip scale packaging (WL-CSP) process in house, instead of subcontracting the packaging process to IC backend service firms as done previously, the sources revealed.

TSMC has been fabricating the fingerprint sensors for iPhone 5s at its 8-inch fabs, while outsourcing the backend services to Xintec, China Wafer Level CSP and Advanced Semiconductor Engineering (ASE).

Due to limited packaging capacity, TSMC may switch part of packaging orders for Qualcomm's chips to STATS ChipPAC, the sources added.

The report concludes by stating that their source notes that TSMC will soon begin producing application processors using a 20nm process and that production will be ramped up significantly starting in the third quarter.