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Functional 512K static random access memory (SRAM) devices containing more than 3.6 million transistors have been successfully fabricated in a 0.25 μm complementary metal–oxide semiconductor technology using compact storage ring x‐ray lithography. In this demonstration a comparison of critical dimension control was made between x‐ray and optical (i‐line and excimer laser) lithography by fabricating SRAM devices using both lithographic techniques. For the x‐ray fabricated devices the channel length, a key device performance parameter, was controlled to within 0.036 μm (3σ), demonstrating the excellent process robustness, and dimensional control available from x‐ray lithography. These SRAMs had excellent electrical characteristics, including cycle times of 1.8 ns and access times of 3.7 ns. The ability of the existing x‐ray lithography infrastructure to produce a fully functional (‘‘perfect’’) chip has been demonstrated in a companion device fabrication program. A 512K SRAM chip of a slightly different design, with 0.35 μm minimum channel length, was fabricated with 100% bit yield using x‐ray lithography. This article describes these device demonstrations, including the observed advantages of x‐ray lithography, as well as the status of IBM’s x‐ray lithography program and associated infrastructure.