An ultraprecision pitch calibration system with a deep ultraviolet (DUV) laser diffractometer for rulers with the pitch of down to 97 nm has been newly constructed in collaboration with Japan Quality Assurance Organization (JQA). A built-in scanning interferometer-based DUV wavelengthmeter and a high-resolution optical diffractometer make every calibration of rulers traceable to the unit of length. Calibrated 100-nm rulers with an expanded uncertainty of 0.04 nm will be used as standards in the inspection of the size of next-generation nanodevices in advanced semiconductor production lines. With the extremely low uncertainty and pitch size comparable with the devices, the rulers will contribute to the improvement of the production yield.