Silicon Carbide (SiC)
Silicon Carbide (SiC) is a third-generation wide-bandgap semiconductor material characterized by its high breakdown electric field, high thermal conductivity, high electron saturation drift velocity, and excellent chemical and thermal stability. It is widely used in power electronics, RF devices, electric vehicles, 5G communication, industrial power supplies, aerospace, and other fields. Its hard and brittle nature makes precision machining a critical step in manufacturing high-performance devices.
Hemei Company possesses profound technical expertise in the precision machining of hard and brittle materials. We have developed an efficient and stable polishing and planarization process specifically for SiC materials. This process enables fully controllable machining from substrate preparation to device-level surface finishing, meeting the stringent surface quality requirements for SiC in high-end applications such as power modules and microwave RF devices.
Application Requirements
The objectives for polishing and surface treatment of SiC materials include:
Reducing surface roughness (Ra) to < 0.5 nm.
Achieving surface flatness (TTV) ≤ 1 μm, with local flatness (LTV) being superior to this value.
Producing surfaces free of scratches, micro-cracks, and sub-surface damage to meet device-level electrical performance requirements.
Compatibility with various polytypes such as 4H-SiC and 6H-SiC, supporting wafer processing from 4-inch to 8-inch diameters.
To achieve these goals, Hemei's process employs customized bonding systems and multi-step polishing procedures, ensuring geometric accuracy and surface integrity during processing.
System Specifications
Hemei's modular polishing systems support the processing of SiC wafers/crystals of various sizes and shapes. The core systems include:
HSM-L/LP Series lapping Equipment: Used for initial material removal and thickness control.
HSM-CMP Series Chemical Mechanical Polishing Systems: Used for achieving ultra-smooth, damage-free surfaces.
Key Subsystems:
Wafer/Crystal-specific Bonding Unit (WB).
SJ/ASJ Series Precision Polishing Fixtures.
C-ASJ Drive Head High-Speed Polishing System.
Process Flow
Bonding and Mounting: The SiC sample is temporarily bonded to a carrier plate using the WB bonding unit and then mounted onto the polishing fixture.
Rough and Intermediate Polishing: Controlled grinding is performed on the HSM-L equipment to remove the process-affected layer.
Fine Polishing: The final polishing is conducted using the HSM-CMP system. Parameters such as pressure, rotation speed, and slurry flow rate are adjusted in real-time to achieve nano-level surface smoothness.
Typical Results
Surface Roughness Ra < 0.5 nm.
Total Thickness Variation (TTV) ≤ 1 μm, Local Thickness Variation (LTV) ≤ 0.3 μm.
Material Removal Rate: 0.5 - 2 μm/min (adjustable).
Suitable for SiC wafers with diameters ≤ 8 inches, supporting common polytypes like 4H/6H-SiC.
Summary
Hemei Company provides a complete and reliable polishing and planarization solution for Silicon Carbide materials. This solution consistently delivers nano-level surface quality and high electrical performance, thereby supporting the industrialization and enhancement of device performance for SiC in high-end fields such as power electronics, RF communication, and new energy vehicles.
