Structure-Performance Relationships of Complexing Agents on the Chemical Mechanical Polishing of 6063 Aluminum Alloy

Abstract

Aluminum alloy has wide applications in many industries due to its unique properties. Chemical mechanical polishing (CMP) is commonly used to treat aluminum alloy to generate mirror-finish surface. In this study, the effects of pH and H2O2 concentration on the CMP of 6063 aluminum alloy were studied. Better CMP performance was obtained in basic media with 1.0 wt% H2O2. Moreover, complexing agents with different structures and functional groups were evaluated for the CMP of Al-alloy, and their structure-performance relationship was systematically studied. It was found that complexing power, steric hindrance, and electrostatic repulsion of complexing agents were important factors determining material removal rate and surface roughness. The complexing agent with high complexing power can favor the dissolution and Al substrate. The complexing agent with large steric hindrance and high charge density can form a stable boundary layer on the surface of substrate and improve its dispersion ability, thereby improving MRR and surface quality. In addition, the amino functional groups of complexing agents exist in the form of neutral molecules at pH 10, which is inferior to carboxyl complexing agents due to their poor static repulsion. X-ray photoelectron spectroscopy analysis confirmed the anchoring of carboxylate anions on the sample surface.

Experimental Investigation on Chemical Mechanical Polishing of ZA27 Alloy Considering Galvanic Corrosion at Zn/Al Interface

“…Sun et al 8 investigated the effect of the complexing agent glycine in a polishing slurry at pH 7.5 on the MRR of the aluminum alloy CMP, and found that glycine and TAZ synergistically formed a weak passive layer on the surface of Al, which protected the surface of Al from the effects of chemical dissolution as well as achieved a high polishing rate. Li et al 9 investigated the effect of complexing agents with different structures and functional groups on the MRR and surface roughness Ra of the aluminum alloy CMP, and found that complexing power, steric hindrance, and electrostatic repulsion of complexing agents were the important factors in determining the MRR and surface roughness Ra. In summary, the pH, H 2 O 2 concentration, and complexing agents of the polishing slurry play an important role in the MRR and surface roughness Ra of the alloy CMP.…”