Reliability Performance of Advanced Organic Interposer (CoWoS®-R) Packages

Organic interposer (CoWoS®-R) is one of the most promising heterogeneous integration platform solutions for high-speed and artificial intelligence applications. Components such as chiplets, high-bandwidth memory, and passives can be integrated into an organic interposer with excellent yield and reliability. This paper presents reliability results for advanced organic interposer packages. Multiple redistribution layers (RDLs) form an effective stress buffer for reducing the stress induced in the C4 joint and its underfill from the mismatch between the top dies and substrate. Four RDL lines with a minimum line width/spacing of 2/2 μm exhibited excellent robustness, ensuring the long functional lives of highperformance computing products. We successfully demonstrated the outstanding fatigue performance of the C4 joint reliability. Various large packages passed stringent reliability tests, specifically TCC (-65°C to 150°C) up to 1300 cycles for heterogeneous integration package and TCG (-40°C to 125°C) up to 2500 cycles for chiplet integration package. The results of the sanity cross-sectional check indicate no interfacial delamination or crack. In addition, an in-depth analysis conducted using finite-element modeling revealed that the packages had superior reliability performance compared with a large monolithic flip-chip package.