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 hydroxyl 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 is. The alcohol additive is selected from methanol, ethanol and glycerol, and the acid solution comprising phosphoric acid. The volume ratio of glycerol to phosphoric acid is between 1:50 and 1: 200, and is preferably 1: 100. The volume 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 comprises an organic acid which is selected from the group consisting of acetic acid and citric acid. The concentration is 10,000 to 12,000 ppm for the acetic acid, and between 500 and 1000 ppm for citric acid.