THE ROLE OF POST-CMP CLEANING SOLUTION ADDITIVES IN MINIMIZING SILICA SLURRY ADHESION ON CU, TA, AND TEOS-DEPOSITED SIO_2 SURFACES

摘要

Adhesion forces between a silica particle and blanket Cu, Ta, and SiO_2 surfaces immersed in a series of commercially-available post-Cu CMP cleaning solutions were measured using the atomic force microscopy (AFM) force curve technique. The series consisted of high pH, TMAH-based cleans that differed in the identity of the additives they employed. The effect of the presence of additives on the magnitude of the measured adhesion was found to be substrate dependent. The silica-Cu interaction was significantly affected by the additives present, whereas the silica-TEOS interaction showed no adhesion in any of the solutions, including a TMAH control solution of similar pH and conductivity. Dip tests of blanket and patterned Cu, Ta, and SiO_2 samples in silica particle dispersions of each of the cleaning solutions showed good correlation between the measured adhesion forces and the residual particle density after dipping for all but one solution-substrate combination.