Pipeline defects, which cause emitter-collector shorts, have been quite well known in bipolar processes. Such defects have been, however, rarely reported in CMOS processes. In our recent implementation of the new submicron CMOS26 process in which SWAMI isolation was used, pipeline defects in n-channel FET's were discovered. The pipelines were caused by enhanced phosphorus diffusion along dislocation lines. The cause of the dislocation lines and a model for the enhanced diffusion mechanism are discussed in this paper.