| TENG Kang,CHEN Guo-mei,NI Zi-feng,QIAN Shan-hua,BAI Ya-wen.Effect of Catalyst Concentration on Chemical Mechanical Polishing Performance of Si Surface of 6H-SiC Wafer[J],48(3):291-296 |
| Effect of Catalyst Concentration on Chemical Mechanical Polishing Performance of Si Surface of 6H-SiC Wafer |
| Received:August 22, 2018 Revised:March 20, 2019 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2019.03.039 |
| KeyWord:silicon carbide chemical mechanical polishing catalyst material removal rate surface roughness particle size distribution |
| Author | Institution |
| TENG Kang |
1. School of Mechanical Engineering, Jiangnan University, Wuxi , China |
| CHEN Guo-mei |
2. School of Mechanical and Electrical Engineering, Wuxi Vocational Institute of Commerce, Wuxi , China |
| NI Zi-feng |
1. School of Mechanical Engineering, Jiangnan University, Wuxi , China |
| QIAN Shan-hua |
1. School of Mechanical Engineering, Jiangnan University, Wuxi , China |
| BAI Ya-wen |
3. Taihu University of Wuxi, Wuxi , China |
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| Abstract: |
| The work aims to improve the material removal rate (MRR) and the surface quality of the Si-face 6H-SiC wafer by chemical mechanical polishing (CMP). CMP was performed on the Si-face of 6H-SiC wafer with a polishing slurry including the different concentrations of Cu2+ and glycine as catalysts and the hydrogen peroxide (H2O2) as an oxidant. The SiC wafer was weighed by a precision balance to calculate the MRR before and after polishing. AFM was used to observe the surface of the SiC wafer and the surface roughness (Ra) was measured. The Zeta potential and particle size distribution of the nano-silica abrasive particles were measured by a Zeta potential meter at different concentrations of Cu2+. The friction and wear tester was used to measure the friction coefficient of SiC wafer with different concentrations of Cu2+. The effects of different pressures and rotational speeds on the MRR and Ra of SiC during CMP were compared. With the increase of Cu2+ concentrations, the MRR increased firstly and then decreased. When the Cu2+ concentration was 300 μmol/L, the MRR had a maximum of 82 nm/h, and in this case, the Ra was 0.156 nm. In contrast, the MRR was 62 nm/h and the Ra was 0.280 nm without the addition of the Cu2+-glycine complex. At the same time, with the increase of the Cu2+ concentrations, on the one hand, the absolute values of the zeta potential of the abrasive particles in the slurry decreased, but was still higher than the absolute value of the zeta potential without the addition of the Cu2+-glycine complex; on the other hand, the average particle diameters of the abrasive particles gradually increased, but was still smaller than the average particle diameters (104.0 nm) without the addition of the Cu2+-glycine complex. In addition, as the Cu2+ concentration increased, the friction coefficient of the SiC wafer firstly increased and then decreased, reaching a maximum of 0.6137 at 300 μmol/L. Finally, as the pressure increased, the MRR increased gradually, but the Ra increased when the pressure was too high. With the increase of the polishing plate speed, the MRR increased firstly and then decreased, but there was no significant changes in the Ra. At the speed of 120 r/min, the MRR had a maximum of 96 nm/h with the Ra of 0.161 nm. As a catalyst, the Cu2+-glycine complex can accelerate the chemical oxidation rate in the CMP of SiC to increase the MRR, and can improve the dispersion stability of the slurry to make the surface quality of the SiC wafer better. In addition, increasing the polishing pressure can enhance the mechanical grinding effect and magnify the MRR, but if the pressure is too high, the wafer surface will be damaged. An increase in the rotational speed of the polishing plate can also increase the MRR, but if the speed is too high, the polishing solution will splash out, lowering the chemical effect and resulting in a decrease of the MRR. |
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