A study of silicon etch process in memory process

With the shrinkage of pattern CD (Critical Dimension), pattern collapse, micro-loading effect and silicon to silicon dioxide selectivity become more challenging in STI (Shallow Trench Isolation) patterning. Pattern collapse is closely related to micro-loading effect. To enhance Si to SiO
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selectivity and suppress micro-loading effect, bias RF pulsing and cycle etch are used [1]. In this paper, the influence of space CD difference on micro-loading effect and bias RF pulsing function in silicon etch process is discussed.