The capex-meets-IP fact first: advanced packaging is not only about density — it is about reliability, because field failures and yield loss are real cost centers. US12347802B2, granted July 2025 to TSMC, patents removing die corners to suppress underfill cracks (CPC H01L 24/20).
Gloss it once. Underfill is a material injected between a die and its substrate to mechanically support the connections. As the package heats and cools, mechanical stress concentrates at the die corners, where the underfill can crack — leading to failures. Removing or shaping the die corners relieves that stress concentration, suppressing the cracks.
Why a capex desk reads it: reliability defects in advanced packages cause yield loss in the fab and, worse, failures in the field that carry warranty and reputational cost. A foundry that owns crack-suppression IP protects the economics of its packaging business on both ends. This is reliability as a cost-control investment, not a feature.
The period framing matters. By 2025, advanced packaging was central to high-value products, and reliability under thermal cycling was a serious concern for dense, high-power assemblies. A TSMC crack-suppression grant reflects the maturation of packaging from "can we build it" to "can we build it reliably at yield."
The caveat we attach: this is a packaging-reliability patent and a defensive asset. It evidences TSMC's focus on package reliability; it does not quantify yield or failure-rate improvement.
For the period investor, the durable point is that packaging reliability is a quiet cost center, and the IP that controls it protects margin. A 2025 underfill-crack grant is a marker of that less-visible side of the packaging business.