Abstract
With the development of ultra-large scale integrated circuits, chemical mechanical planarization (CMP) has been one of the most critical processes to achieve global planarization. The ionic strength of slurry is one of the key factors influencing the material removal rate and surface quality during CMP process. In this paper, potassium nitrate was used to enhance ionic strength in baseline slurry, and the removal mechanism of copper and TEOS (tetraethylorthosilicate) were investigated. The results showed that, when the potassium ionic strength was 100mM, TEOS and copper removal rate can reach 768Å/min and 395Å/min respectively, and the removal rate selectivity ratio was 1.98 which can match well with the industrial production requirement. On pattern wafer, after polishing 60s, the dishing and erosion were amended to be 570 ± 50Å and 195 ± 30Å respectively, and the number of total defects was about 9. Such results provide guiding significance for industrial production.
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