Polishing mechanism of single-crystal silicon in fixed-abrasive chemical mechanical polishing with different solutions

XZ Yang and SL Zhang and FM Lian and X Yang and K Yamamura and ZD Jiang, APPLIED SURFACE SCIENCE, 705, 163494 (2025).

DOI: 10.1016/j.apsusc.2025.163494

Chemical mechanical polishing (CMP) is a widely used polishing technique for Si wafers, but cost and environmental concerns have always been open questions. This study proposed a novel fixed-abrasive CMP (FACMP) using environmentally friendly salt solutions to improve polishing efficiency while reducing polishing costs. The surface modification of the Si surface in three kinds of salt solutions, i.e., ultrapure water, NaCl and Na2CO3 aqueous solutions, was investigated via three modification experiments and molecular dynamics (MD) simulations. Surface modification, mainly oxidation of the Si surface, occurred in these three liquids. Na2CO3 aqueous solution was found to be an effective liquid for modifying the Si surface, in which the highest modification rate was obtained. Etching of the Si surface occurred in the Na2CO3 aqueous solution, and CO32-ions were involved in the modification and etching of the Si surface; an etching rate of 0.14 mu m/h was observed. In addition, FACMP of 4-inch Si wafers was conducted in these three liquids, and the highest material removal rate of 4.252 mu m/h was obtained in the Na2CO3 aqueous solution. This study provides a possible way to realize a low-cost, high-efficiency, and environmentally friendly polishing method for Si wafers and even other semiconductor materials.

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