The use of different barrier slurries for copper chemical mechanical planarization (CMP) creates a challenge for post-CMP cleaning.Differences in barrier slurries include,but are not limited to,pH,the abrasive particle material and size,and copper corrosion inhibitor(s).Cleaning tests were conducted to observe the interaction between the barrier slurry and the cleaning process.The barrier slurries differed in pH and all contained benzotriazole (BTA) as a copper inhibitor.The pH of a solution containing BTA will determine the properties of the BTA-Cu complex and the subsequent conditions for removing this film in the cleaning process.Therefore,the cleaning process was varied to study the effect of pH,chemical components,and chemical sequence on the removal of the BTA-Cu complexes left by the barrier slurry on copper surfaces.It was found that the pH of the barrier slurry did affect the efficacy of various cleaners.Also,the use of certain additives and 2-step chemical cleaning improved cleaning performance on barrier slurries of varying pH.The results of this work indicate that,for optimum results,the cleaning process should be tuned to the barrier slurry.
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