| 摘要 |
PURPOSE: Purified carboxylic acids and their derivatives and in particular purified citric acid, malonic acid, oxalic acid and ammonium citrate are provided to be use in cleaning after chemical mechanical polishing of integrated circuits. CONSTITUTION: Citric acid compositions have less than 100 ppb iron cations, 20 ppb calcium cations, and 100 ppb barium cations, preferably less than 10 ppb for a cationic impurity. The citric acid is prepared by exposing technical grade citric acid in deionized water to a styrene-divinyl benzene cation exchange resin having sulfonic acid or hydrochloric acid functionality and collecting said ion exchanged effluent.
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