ELECTROPOLISHING ELECTROLYTE AND METHOD FOR PLANARIZING A METAL LAYER USING THE SAME

摘要

The present electropolishing electrolyte comprises an acid solution and an alcohol additive having at least one hydroxy group, wherein the contact angle of the alcohol additive is smaller than the contact angle of the acid solution on a metal layer under electropolishing. The alcohol additive is selected from methanol, ethanol and glycerol, and the acid solution comprises phosphoric acid. The volumetric ratio of glycerol to phosphoric acid is between 1:50 and 1:200, and is preferably 1:100. The volumetric ratio is between 1:100 and 1:150 for methanol to phosphoric acid, and between 1:100 and 1:150 for ethanol to phosphoric acid. In addition, the acid solution further comprises an organic acid selected from the group consisting of acetic acid and citric acid. The concentration is between 10000 and 12000 ppm for the acetic acid, and between 500 and 1000 ppm for citric acid.