The mechanical strength of hydrogen-annealed Czochralski silicon (H-2-annealed) wafers was investigated with emphasis on the generation of slip dislocations by oxide precipitates. Thermal stress, which was far larger than that generated in actual device processes, was applied to H-2-annealed wafers after thermal simulation of a low-temperature process (low-temperature simulation) or a high-temperature process (high-temperature simulation). It was found that slip generation by oxide precipitates did not occur in the case of the low-temperature simulation, while many slip dislocations were generated in the case of the high-temperature simulation. The:experimental results can be explained by the effect of precipitate size on slip generation. It was concluded that H-2-annealed wafers have no mechanical strength problems during actual low-temperature processes.