POLISHING SLURRY CONTAINING RARE EARTH ADDITIVE OF DUAL ATOMIC VALENCY

摘要

PROBLEM TO BE SOLVED: To obtain a polishing slurry which enables a refractory metal to act as a polish stop member by incorporating a suspension contg. abrasive particles and rare earth ions of a dual atomic valency or a colloidal hydroxide thereof into the slurry. ;SOLUTION: This slurry contains a suspension contg. 0.2-20 wt.% abrasive particles having a particle size of 10-1,000 nm and selected from among alumina, silica, ceria, etc., and 0.05-2 wt.% rare earth ions having a dual atomic valency (e.g. Ce4+ or Pr4+) or colloidal hydroxide thereof having a particle size of 5-100 nm. On the top of an SiO2 substrate 1 having a pattern formed thereon, an Nb liner 3 is placed as a polish stop member and thereon is formed an Al layer 2. The Al layer 2 is polished at a certain polishing rate with the polishing slurry. Since the Al layer of the patternized part is thinner than the other parts, it is polished faster. When the polishing reaches the Nb liner 3, the rare earth ions in the slurry are oxidized into Nb2O5, which stops the polishing process. Then, Nb2O5 is removed with a silica slurry.;COPYRIGHT: (C)2000,JPO