Stress release for shallow trench isolation by single-wafer, rapid-thermal steam oxidation

Shallow trench isolation (STI) is the predominant isolation technology for advanced integrated circuits. Dislocations are often found at STI after repeated thermal cycles. For STI integrity, it is insufficient to have excellent STI patterning fidelity and rounded corners; it is also critical to have minimal thermal mismatch during oxidation and dislocation-free high-temperature annealing. Single-wafer, rapid-thermal steam oxide is found to be an excellent candidate for STI liner oxide and sacrificial oxide in that it provides lower thermal budget, rounded top and bottom corners, and significant improvement in stress release, the mechanism of which is also presented.