Abstract
In today’s competitive semiconductor environment, product performance and market timing has never been more valuable. Design IP, speed to market, and taking advantage of the most advanced technology are three ways fabless companies can maintain an advantage over the competition. Foundries target these demands by offering superior support, competitive technology, and rapid development cycles. Using the advanced tool suites of SEM, FIB, TEM, and Atomic Force NanoProbing (AFP) the failure analysis community now has the ability to investigate and compare foundry performance on the device level. The 28 nm LP Qualcomm “SHELBY” die is dual-sourced from both Samsung and TSMC, and is the primary die in the MDM9215 4G/LTE modem used in several smartphones. This represents a unique case of leading technology, available to the public, to qualify for electrical performance on the device level using the AFP and the corresponding physical differences using SEM and TEM. These advanced FA techniques were employed and were able to identify manufacturing differences between foundries. They were then used to relate the physical variations with the electrical device performance. The HG11-N3877 fabricated by TSMC and the HG11-N9204 fabricated by Samsung were the subjects of this comparison (see Error! Reference source not found.). The investigation located spatial and geometric variations of the SRAM devices using cross sectioning and TEM imaging. This was followed by Electrical Characterization of multiple SRAM Cells using the AFP. The electrical measurements showed clear differences in device parameters. These differences highlight manufacturing process differences between the two companies that could directly relate to chip performance.
