China-based SJ Semi, a middle-end-of-line foundry offering a 12-inch wafer bumping and testing service, raised a $340M Series C extension at a $1.8B valuation
Stephanie Li / DealStreetAsia :
Context & Ripple Effects
China's chip buildout has so far been funded through public-market mega-rounds for the big foundries: SMIC's $6.62B Shanghai debut in 2020 and Hua Hong's ~$2.5B Shanghai IPO approval for its Wuxi plant last year. Both point the same direction Beijing has been pushing — mature nodes like 65nm–40nm rather than sub-14nm.
SJ Semi's raise extends that arc into the private market and into a different layer of the stack: middle-end-of-line services like 12-inch wafer bumping and testing, which sit between fab output and final assembly. As export controls squeeze access to front-end advanced tooling, the mid/back-end is where Chinese capacity can still be built with fewer chokepoints.
First-order effects
- SJ Semi gains $340M to scale its 12-inch bumping and testing lines at a $1.8B valuation, validating middle-end-of-line services as a fundable category alongside the foundry names.
Second-order effects
- The new capacity feeds directly off the mature-node wafer volume Hua Hong and SMIC are adding, easing a potential back-end bottleneck for their 12-inch output while competing with existing OSAT players for bumping equipment and test capacity.
Third-order effects
- If private capital keeps following the public money down the stack, China's semiconductor ecosystem becomes progressively self-sufficient at trailing nodes — front-end fabs, middle-end services, and packaging — precisely the layers US-led controls hit least directly.
The trend: China's semiconductor financing is migrating from headline foundry listings toward the mid- and back-end of the line, building out mature-node self-sufficiency around export-control chokepoints.