Single-side grinding of silicon carbide crystal rods
Single-side grinding of silicon carbide ingots is a crucial process in silicon carbide substrate manufacturing for the precision machining of ingot end faces or the surfaces of wafers after cutting. Unlike external cylindrical grinding, single-side grinding focuses on achieving high planarity, low surface roughness, and precise thickness control on a single surface, providing a foundation for subsequent wafer polishing or device manufacturing.
Precision Single-Side Grinding Machine:
1. High-rigidity structure: Resists the enormous cutting forces during silicon carbide grinding.
2. Air hydrostatic spindle/high-precision spindle: Drives the diamond wheel at high speed (typically > 1,500 rpm), ensuring smooth and vibration-free operation.
3. Vacuum chuck or special fixture: Flatly adheres the wafer/ingot, preventing deformation and slippage during clamping (especially crucial for thin wafers).
4. Online thickness measurement system: Monitors wafer thickness and TTV in real time, enabling closed-loop control.
5. Multi-axis CNC system: Precisely controls parameters such as the wheel path, feed rate, and speed.
Process (using wafer grinding as an example):
Loading: The wafer is vacuum-adhered to a precision ceramic chuck to ensure no loosening.
Rough grinding: High feed rate removes most of the material (e.g., removing the cutting damage layer of 30μm), quickly reaching the vicinity of the target thickness.
Fine grinding: Reduces the feed rate, using multiple passes of progressive grinding to optimize planarity (TTV < 2μm) and surface roughness (Ra < 0.2μm).
Online measurement and compensation: The thickness sensor provides real-time feedback, automatically adjusting the wheel position to compensate for wear.
Cleaning and drying: Removes surface debris and coolant residue.
