Picosecond Laser-Assisted Chemical Mechanical Polishing (CMP): Aiming at the Si-Face of Single-Crystal 6H-SiC Wafer

Gao, Bin; Guo, Dan; Zhang, Xin; Chen, Gaopan; Pan, Guoshun

doi:10.1149/2162-8777/abf726

Cited by 8 publications

(4 citation statements)

References 29 publications

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“…[48] The laser irradiation method refers to the irradiation of a 4H-SiC wafer by an ultra-fast laser, including femtosecond laser, nanosecond laser, and picosecond laser. [56,57] Due to its high pulse frequency and high energy density, the ultrafast laser introduces micro-pits or deep grooves at the surface of 4H-SiC wafers, which increases the effective contact area between the surface of 4H-SiC wafer and the polishing slurry during CMP. Hence, the efficiency of CMP may be improved.…”

Section: Pre-processingmentioning

confidence: 99%

Chemical–Mechanical Polishing of 4H Silicon Carbide Wafers

Wang

et al. 2023

Adv Materials Inter

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Abstract4H silicon carbide (4H‐SiC) holds great promise for high‐power and high‐frequency electronics, in which high‐quality 4H‐SiC wafers with both global and local planarization are cornerstones. Chemical–mechanical polishing (CMP) is the key processing technology in the planarization of 4H‐SiC wafers. Enhancing the performance of CMP is critical to improving the surface quality and reducing the processing cost of 4H‐SiC wafers. In this review, the superior properties of 4H‐SiC and the processing of 4H‐SiC wafers are introduced. The development of CMP with chemical, mechanical, and chemical–mechanical synergistic approaches to improve the performance of CMP is systematically reviewed. The basic principle and processing system of each improvement approach are presented. By comparing the material removal rate of CMP and the surface roughness of CMP‐treated 4H‐SiC wafers, the prospect on the chemical, mechanical, and chemical–mechanical synergistic improvement approaches is finally provided.

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Section: Pre-processingmentioning

confidence: 99%

Chemical–Mechanical Polishing of 4H Silicon Carbide Wafers

Wang

et al. 2023

Adv Materials Inter

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“…Shearing force ensures that the workpiece surface material is removed. The method is suitable for polishing optical parts of any geometric shape, with high processing speed, high efficiency, and high processing precision, with the processed surface roughness reaching nanometer level [24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, due to the lack of effective damage precursor characterization methods, there is relatively little research on the correlation between damage precursor and damage in high-energy laser systems. Therefore, it is of great significance to develop a comprehensive damage precursor detection system for different damage precursor types [21][22][23][24][25][26][27]. The main objective of this study is to investigate the surface quality of single-crystal silicon optics fabricated with different polishing processes through laser-induced SC imaging and photothermal weak absorption imaging techniques [28].…”

Section: Introductionmentioning

confidence: 99%

Towards Investigating Surface Quality of Single-Crystal Silicon Optics Polished with Different Processes

et al. 2022

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A series of cleaning and etching experiments utilizing organic solvent or weak alkali solutions were performed on single-crystal silicon optics polished with different processes. Polishing-introduced fractured defects in the subsurface layer were systematically characterized using laser-induced scattering imaging and photothermal weak absorption imaging techniques. A white-light interferometer also measured the surface morphology and roughness of the samples to evaluate the surface quality of the optics. The results show that the organic solvent cleaning process can eliminate the surface contamination resulting from the environment and the near-surface polishing-introduced impurities but can not remove the fractured defects in the subsurface layer of the optics. By contrast, weak alkali solution can effectively expose the subsurface defects and decrease the concentration of the embedded absorbing impurities to some extent. The results also imply that the polishing process has a crucial effect on the surface quality (e.g., surface roughness and error) and optical performance (e.g., surface absorption) after the subsequent treatments such as cleaning or etching. The corresponding methodology of cleaning and characterization can serve as a predictive tool for evaluating the polishing level and laser damage resistance of the single-crystal silicon optics.

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“…[12][13][14][15] In order to improve chemical oxidation, KMnO 4 has become the most widely used oxidant. [14][15][16] However, KMnO 4 will be affected by many factors during the oxidation process, resulting in low efficiency of the polishing slurry and scratches, which will affect the quality of the wafer. The processing efficiency and quality of SiC substrates have always been the focus of some researchers.…”

mentioning

confidence: 99%

Effect of Ferric Nitrate on Semi-Insulating 4H-SiC (0001) Chemical Mechanical Polishing

Wang¹,

Liu²,

Zhang³

et al. 2022

ECS J. Solid State Sci. Technol.

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Semi-insulating 4H-SiC(0001) has high hardness and high chemical inertness, making it difficult to obtain high material removal rates during chemical mechanical polishing (CMP). In this paper, the role of chemical additive ferric nitrate in semi-insulating 4H-SiC(0001) CMP with α-alumina as abrasive and KMnO4 as oxidant is discussed. The results showed that 0.5 wt% ferric nitrate can increase the removal rate of semi-insulating 4H-SiC(0001) by 34%, while the semi-insulating 4H-SiC(0001) surface roughness Ra was reduced from 0.123 to 0.110 nm. The key point was that the coefficient of friction of the polishing slurry was effectively reduced, which was beneficial to the ploughing effect of the α-alumina abrasive with vermicular thin section morphology which had the highest removal rate. In addition，the chemical composition of 4H-SiC (0001) corrosion layer was analyzed by X-ray photoelectron spectroscopy under different corrosion conditions. Si 2P spectrum analysis showed that O atoms only attack C atoms to produce Si-C-O structure under acidic conditions, whereas, with the addition of ferric nitrate, O atoms not only attacked C atoms, but also attacked Si atoms to produce softer SiO2 and Si-Ox-Cy structures. The chemical mechanical polishing mechanism of Semi-insulating 4H-SiC (0001) is also given.

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Picosecond Laser-Assisted Chemical Mechanical Polishing (CMP): Aiming at the Si-Face of Single-Crystal 6H-SiC Wafer

Cited by 8 publications

References 29 publications

Chemical–Mechanical Polishing of 4H Silicon Carbide Wafers

Chemical–Mechanical Polishing of 4H Silicon Carbide Wafers

Towards Investigating Surface Quality of Single-Crystal Silicon Optics Polished with Different Processes

Effect of Ferric Nitrate on Semi-Insulating 4H-SiC (0001) Chemical Mechanical Polishing

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