Study on Circle Defect Induced by TARC (Top Anti-Reflective Coating) Bubbles

Although TARC is widely used in semiconductor photolithography processes, the understandings of TARC related defects are still far from completeness. In this paper, the root causes and corrective actions of TARC related circle defect were studied. The results showed that the circle defect was induced by TARC bubbles and could be significantly decreased or totaly removed by using several different treatments. Among these treatments, the optimization of TARC coating process by adjusting the spin speed at the final dry step displayed more attractive results. In addition, the TARC thickness, profile, uniformity as well as the related wafer CD (critical dimension) uniformity by applying the new TARC coating recipe were carefully checked and did not show any deterioration.