On June, 2024, Mipox Corporation successfully completed an innovative chamfering and notch polishing test for 8-inch silicon carbide (SiC) wafers. Utilizing Mipox's specialized polishing film technique, the company achieved superior chamfer quality and processing efficiency, setting a new benchmark in wafer polishing.
Purpose and Methodology of the Test
The goal was clear: demonstrate the capability and efficiency of the polishing film method in edge and notch chamfering for 8-inch SiC wafers. With no existing standardized methods for notches, Mipox customized processing conditions specifically tailored to the wafers provided by the client company. Polishing tests were carried out using:
- Edge polishing equipment (Semi-automatic machine: SFF-200)
- Notch polishing equipment (Prototype machine: 450RD) Precision measurements were recorded using advanced digital microscopes (KEYENCE VHX-500), edge profilers (Yuhi Electronics EPRO212EN), and digital calipers for accurate diameter assessments.
Key Results and Observations
Mipox successfully demonstrated that their polishing film method effectively chamfers and polishes wafer edges and notches, outperforming traditional grinding techniques. Key advantages identified include:
- High-Quality Chamfering: Excellent chamfer quality with minimal risk of chipping, significantly reducing wafer defects.
- Enhanced Efficiency: Polishing speed up to three times faster than grinding methods, greatly improving production throughput.
- Consistency and Stability: High reproducibility with minimal variation between individual wafers.
- Flexibility and Versatility: No need for multiple grinding wheels; the film can adapt to different edge profiles efficiently.
Comparative Advantages Over Other Methods
Compared to traditional grinding methods:
- The polishing film method eliminates concerns about grindstone wear.
- Ensures stable processing conditions with fewer variations.
- Significantly faster throughput.
Against laser cutting methods:
- Reduced equipment maintenance costs.
- Superior processing speed and higher throughput.
- More mature and reliable compared to the still-developing laser chamfering method.
Versus slurry polishing methods:
- Capable of precise chamfering, something challenging with slurry polishing.
- Comparable surface finish quality achievable without the use of harsh chemicals, thus eliminating the need for additional cleaning.
Applications and Future Proposals
The Mipox film polishing method is not only ideal for new wafers but also highly suitable for reclaiming SiC wafers. It enables precise edge repair and the removal of unnecessary films with minimal impact on wafer diameter. For mass production scenarios, Mipox recommends its fully automatic NME-68-SiC machine, while smaller production volumes could efficiently utilize the semi-automatic SFF-200 system.
Conclusion
Mipox Corporation's innovative polishing film method sets a new industry standard for SiC wafer chamfering and notch polishing, providing unmatched efficiency, precision, and flexibility in semiconductor manufacturing.