Evaluation technique of gate oxide damage

Gate oxide damage by plasma processing was evaluated using structures with various antenna lengths. The gate oxide damage by plasma processing was found to be monitored quantitatively by measuring the charge to breakdown, Q/sub BD/. From the Q/sub BD/ measurements, we have confirmed that the degradation occurs during overetching, not in main etching. Plasma current was calculated from the decrease of Q/sub BD/ during the etching. The breakdown spot in the gate oxide was detected by photon emission and TEM. The LOCOS structure plays an important role for the degradation by plasma damage. In this paper, it is demonstrated that the Q/sub BD/ method is effective for realizing a highly reliable process against plasma damage.<
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