NVIDIA's ambitious Rubin Ultra GPU design, intended as a next-generation AI accelerator, is encountering severe manufacturing hurdles. Global Semi Research reports the company's next-gen packaging technology, CoWoS-L, is struggling to support the 2+2 die package with four silicon dies and sixteen HBM4E modules. The core issue: warping in the substrate causes compute dies to lose contact with the underlying board, jeopardizing performance. NVIDIA had planned mass production for 2027, but TSMC's current packaging limitations now threaten this timeline. CoPoS (Chip-on-Panel-on-Substrate) is emerging as a potential alternative, though its pilot lines won't launch until 2026 at the earliest.

This shift could delay Rubin Ultra's debut beyond 2027. The standard Rubin GPUs are already shipping, but the Ultra variant's packaging woes highlight the immense technical challenges in scaling next-gen chip designs. This setback underscores the critical role of packaging technology in realizing cutting-edge AI hardware ambitions.