High-density memories and high-speed CPUs are usually realized by reduction of the size of semiconductor cells in Large Scale Integrations (LSIs). Representative length scale of Ultra Large Scale Integration (ULSI) cells is going to be in nano-meter order. Dislocation accumulation during the production process in the electron channel of semiconductor device is one of the most serious problems. Dislocation accumulation has an enormous effect on the electronic state of the device. Therefore, the evaluation and suppression of dislocation accumulation are crucially important for the design and development of semiconductor device structure. In this study, we numerically analyze the suppression of dislocation accumulation in the shallow trench isolation type ULSI cells. Accumulation of dislocations is analyzed by employing a technique of crystal plasticity analysis and we evaluate the dislocation density distribution and total length of dislocations in the silicon substrate. Possibilities for the suppression of dislocation accumulation are discussed.