Stress analysis of shallow trench isolation for 256MDRAM and beyond

The stress generation of the shallow trench isolation has been systematically investigated using the stress simulation and the experiment. It is found that the scale-down of the isolation pitch causes a remarkable stress generation due to the overlap of the stress from both trench sides. Therefore a small isolation pith causes the crystal defects generation with ease. We carried out the stress analysis against the various process parameters in detail. The high temperature sacrificial oxidation can effectively eliminate the stress generation. It was confirmed that enough isolation characteristics can maintain up to 0.1 mu m regime to give a careful consideration of the stress reduction.