Floating-gate-type Flash memories are fabricated on Czochralski ͑CZ͒ silicon wafers. A large amount of residual misalignment in reticle shots at the photolithography process step and the programing failure are observed in the low oxygen concentration wafer. To investigate the origin of misalignment and programing failure, X-ray topography, optical microscope observation followed by preferential etching and laser scattering tomography observation are performed. Slip propagation from wafer edge to wafer center and surface dislocation are observed in the area where misalignment and programing failure are occurred. Misalignment and programing failure are explained by the plastic deformation of wafer by the relaxation of internal stress during the processes. In the high Oi wafer, we observed that oxygen precipitates ͑OPs͒ prevent the propagation of slip. We conclude that the OPs have a strong effect on the suppression of slip propagation, i.e., Flash memory characteristics.

In order to improve the yield enhancement speed, we adopt data mining analysis. The root cause of crack in silicon substrate induced by scrubber tool was found by data mining approach. It could not be detected by conventional knowledge-based pre-filtering approach. As a countermeasure, we switched the scrubber from high pressure clean tool to moderate pressure clean tool.

Floating-gate type Flash memories are fabricated on Czochralski (CZ) silicon wafers. A large amount of residual misalignment in reticle shots at photolithography process step and the programming failure are observed in the low oxygen concentration wafer. The above are explained by the plastic deformation of wafer by the relaxation of internal stress during the processes.