Research on the Chemical Mechanical Polishing Process of Aluminum Alloy Wafers with Acidic Slurry

Abstract

Aluminum alloy has low density, good thermal conductivity, and low resistivity, which has been widely used in the fields of the defense industry, aerospace, and machinery manufacturing. As technology advances, there is a growing demand for high-precision parts and green processing. In this paper, a green chemical mechanical polishing (CMP) slurry for aluminum alloy is developed to optimize the rotational speed and pressure and improve the quality of polished aluminum alloy surface. The influence of CMP slurry composition on the quality of aluminum alloy surface and its mechanism are analyzed. Orthogonal experiments and single-factor experiments are used to investigate the effects of CMP slurry composition and process parameters on the surface quality of polished aluminum alloy. A green chemical mechanical polishing slurry consisting of deionized water, 6 wt.% SiO2, 2 wt.% H2O2, and citric acid to adjust pH=3 was proposed, with the pressure of 24 kPa and rotational speed of 90 r/min. After the CMP of aluminum alloy, surface roughness was reduced from 45.587 nm to 0.876 nm in the scan range of 70 μm × 50 μm. The mechanism was analyzed by X-ray photoelectron spectroscopy (XPS).