trailing edge / mature node

Trailing edge or mature nodes are older, larger process technologies (typically 28nm and above) that remain in high-volume production for cost-sensitive and specialty applications. Mature node range: 180nm, 130nm, 90nm, 65nm, 40nm, 28nm—fully depreciated fabs with stable, well-characterized processes. Applications: (1) Automotive—MCUs, power management, sensors (reliability-proven, long lifecycle); (2) Industrial—motor controllers, PLCs, power conversion; (3) IoT—connectivity chips, microcontrollers (cost-sensitive); (4) Analog/mixed-signal—ADCs, DACs, RF transceivers (don't benefit from scaling); (5) Power—GaN/SiC drivers, IGBT controllers; (6) Display—driver ICs, timing controllers. Why not scale further: (1) Analog circuits don't improve with smaller transistors; (2) High-voltage devices need larger geometries; (3) Cost—advanced node mask sets ($15M+) vs. mature ($100K-$1M); (4) Design cost—advanced node design $100M+ vs. mature $1-10M; (5) Sufficient performance—many applications don't need cutting-edge speed. Economics: depreciated fabs have lower cost per wafer, high margins for foundries. Mature node foundries: TSMC, UMC, GlobalFoundries, SMIC, Hua Hong, Tower Semiconductor, Dongbu HiTek. Supply concerns: 2021 chip shortage highlighted dependence on mature nodes—automotive, industrial severely impacted. New investment: CHIPS Act and geopolitical factors driving new 28nm+ fab construction (previously underinvested). Market size: mature nodes represent ~50% of total wafer production volume. Strategic importance increasingly recognized as essential infrastructure alongside leading-edge production.