Self-Conditioning Fixed Abrasive Pad in CMP

It has been known that overpolishing in chemical mechanical polishing (CMP) depends on pattern selectivity as a function of density and pitch, and use of a fixed abrasive pad is one method which can improve the pattern selectivity. This paper introduces the fixed abrasive pad using the swelling characteristic of hydrophilic polymers, which can acquire self-conditioning during CMP. When applied to tungsten blanket wafers, the fixed abrasive pad showed better pattern selectivity compared to the general polishing process, and, also, erosion was measured for ∼20 nm or less at even 100% overpolishing.