Customer demand for AI and HPC processors is driving a much greater use of advanced packaging technologies, particularly TSMC's chip-on-wafer-on-substrate (CoWoS) services. As things stand, TSMC is just barely meeting the current demand for this packaging method – never mind future demand – which is why last year the company announced plans to more than double CoWoS capacity by the end of 2024. But as it turns out, just doubling capacity once won't be enough, and the world's largest contract maker of chips is going to have to keep scaling up at a rapid pace.

At its European Technology Symposium last week TSMC announced plans to expand CoWoS capacity at a compound annual growth rate (CAGR) of over 60% till at least 2026. As a result, TSMC's CoWoS capacity will more than quadruple from 2023 levels by the end of that period. And keeping in mind that TSMC is prepping additional versions of CoWoS (namely CoWoS-L) that will enable building system-in-packages (SiPs) of up to eight reticle sizes, increasing CoWoS capacity by four-fold in three years may still not be enough. The good news is that the various third-party off-site assembly and testing (OSAT) providers are also expanding their CoWoS-like capacity, so the demand for advanced packing isn't a problem that TSMC is facing (or resolving) on their own.

And CoWoS isn't the only advanced packaging technology line whose capacity TSMC is looking to rapidly expand. The company also has its system-on-integrated chips (SoIC) 3D stacking technology which adoption is poised to grow in the coming years. To meet demand for its SoIC packaging methods TSMC will expand SoIC capacity at a 100% compound annual growth rate by the end of 2026. As a result, SoIC capacity will grow by eight-fold from 2023 levels by late 2026.

Overall, TSMC itself expects leading-edge SiPs for demanding applications like AI and HPC will adopt both CoWoS and SoIC 3D stacking technologies in the coming years, which is why it needs to increase capacity for both methods to be able to build those highly-complex processors.