Effective Improvement of Chemical Mechanical Polishing for Silicon Wafers Using Nitrogen-Containing Heterocyclic Compounds Slurry

Abstract

Silicon wafers are widely used in system on chip (SoC) manufacturing, and accelerating the material removal rate (MRR) of silicon wafers in chemical mechanical polishing (CMP) has become a research hotspot. Here, four nitrogen-containing heterocyclic compounds additives, piperazine, imidazole, 1,2,4-triazole, and benzotriazole, were added to the polishing slurry to improve the MRR of silicon wafers, and their effects and mechanisms were investigated. Results showed that imidazole, 1,2,4-triazole, and benzotriazole effectively increased the MRR of silicon wafers, while piperazine did not improve the MRR, imidazole and benzotriazole increased by 42.6% and 20%, with 1,2,4-triazole showing a particularly significant effect, with a 50% increase. When the concentration of 1,2,4-triazole was 0.06 mol l −1 , the MRR increased by 100%, reaching 343.347 nm min −1 , and the surface roughness declined from 1.06 to 0.806 nm. In addition, the polishing slurry maintained good dispersibility. The polishing mechanism was analyzed using X-ray photoelectron spectroscopy, revealing that nitrogen atoms bond with silicon to form Si-N bonds, accelerating the hydrolysis of silicon wafer surface, and enhances the interaction of the abrasive with the silicon surface. This study provides new insights into the interaction between polishing slurry and silicon wafer surfaces, offering innovative CMP strategies for expanding the production of silicon wafers.