Document:
1. Introduction
Diamond, known as the hardest material in nature, possesses extremely high thermal conductivity, excellent optical transparency (especially from ultraviolet to far-infrared wavelengths), good chemical stability, and an extremely low coefficient of friction. Consequently, it holds irreplaceable application value in high-end industrial and technological fields. Single-crystal or thin-film diamond is widely used in cutting tools, thermal management substrates, optical windows, heat dissipation for high-power devices, quantum sensing, and biomedical equipment.
Hemei Company has profound technical expertise in the processing and polishing of ultra-hard materials. It has developed a systematic, high-precision polishing and surface treatment process specifically for diamond materials. This process enables full-process control from rough machining to nanoscale surface finish, ensuring that diamond materials meet the requirements for "device-grade" or "optical-grade" applications.
2. Application Requirements
The objectives for polishing and processing diamond materials include:
Total Thickness Variation (TTV) controlled within ±1.5 micrometers.
Surface Roughness (Ra) reduced to less than 1 nanometer.
Surface free of micro-cracks and sub-surface damage, meeting the requirements for optical coating or device integration.
Maintaining good crystal integrity and edge integrity.
To achieve these objectives, the Hemei process employs a combination of specialized bonding systems, multi-step lapping, and chemical mechanical polishing, ensuring geometric accuracy and surface quality during processing.
3. System Specifications
Hemei's modular polishing system can flexibly adapt to diamond samples of different sizes and forms (including single crystal, polycrystalline thin films, and irregular shapes). The core system includes:
HSM-UHP Series Ultra-Hard Material Lapping Equipment:
Used for initial shaping and thickness control of diamond, equipped with a high-rigidity spindle and diamond-specific lapping plates.
HSM-DCMP Series Diamond-specific Chemical Mechanical Polishing (CMP) System:
Used for achieving ultra-precision polishing of diamond surfaces, capable of nanoscale surface flatness and low-damage control.
Key Subsystems:
Diamond-specific Bonding Unit (DBU):
Provides high-strength, low-stress temporary bonding, adaptable to diamond samples of different thicknesses and shapes.
D-ASJ Series High-Rigidity Polishing Fixtures:
Specifically designed for diamond, ensuring stable clamping and preventing edge chipping.
High-Speed Drive Head Polishing System:
Enables uniform material removal under high rotational speed and pressure, improving processing efficiency.
4. Processing Flow
4.1 Mounting, Fixing, and Lapping
Bonding: Use the Hemei bonding unit to temporarily bond the diamond sample to a ceramic or glass substrate. The system automatically compensates for thickness differences to ensure initial parallelism.
Clamping: Mount the bonded assembly onto the vacuum chuck of the ASJ series polishing fixture.
Lapping: Place the fixture onto the lapping plate of the HSM equipment. The system operates at speeds up to 120 rpm, while delivering a diamond microparticle slurry through a precision fluid supply system. This stage aims to rapidly remove material and control overall thickness and flatness.
4.2 Mounting, Fixing, and Polishing
Transfer and Cleaning: After lapping, clean the sample and remove it from the support plate.
Precision Polishing:
Option A (Optical-grade Surface): Use the Hemei HSM-CMP system. The diamond is fixed directly via a custom-designed polishing head. The system supports real-time adjustment of multiple parameters (pressure, rotational speed, polishing fluid composition, etc.) to achieve low-damage, high-flatness polishing.
Option B (High-Efficiency Mass Production): Load the diamond into a fixture equipped with a dedicated holder for high-speed polishing. Suitable for applications requiring high surface quality but not necessarily optical-grade levels.
5. Results
Using the Hemei polishing system to process diamond materials yields an extremely high-quality surface state, ready for subsequent coating, bonding, or device fabrication. The system achieves excellent surface integrity while ensuring high efficiency.
By optimizing process parameters (such as pressure, rotational speed, and polishing fluid composition), the Hemei process can achieve a stable Material Removal Rate (MRR) of 0.8-2 μm/h for diamond, striking an optimal balance between processing efficiency and surface quality.
The following data is based on results measured from a batch of 8 pieces of 10x10 mm² single-crystal diamond processed on the HSM-DCMP system:
|
Parameter |
After Lapping (Initial) |
After Polishing (Final) |
Target Specification |
|
Surface Roughness (Ra) |
~150 nm |
<1 nm |
Ra < 2 nm |
|
Total Thickness Variation (TTV) |
- |
< ±1.2 μm |
TTV < ±2 μm |
|
Material Removal Rate (MRR) |
- |
0.8-2 μm/h |
- |
|
Edge Integrity |
- |
No chipping, no edge breakage |
Passes visual and microscopic inspection |
The above parameter results are from Hemei Semiconductor (Suzhou) laboratory only.
Typical Diamond Processing Results
Sample Type: Single-crystal / Polycrystalline diamond (size customizable)
Material Removal Rate (MRR): 0.8-2 μm/h
Final Ra Value: <1 nm
Flatness (TTV): < ±1.2 μm
Edge Condition: Intact, undamaged
The above parameter results are from Hemei Semiconductor (Suzhou) laboratory only.
Summary:
The polishing solution provided by Hemei Company for diamond materials integrates high-rigidity equipment, specialized fixtures, and process optimization. It can stably and reproducibly achieve nanoscale surface finish and micron-level geometric precision, strongly supporting the industrial application of diamond in high-end optics, power devices, quantum technology, and other fields.
If further addition of specific equipment models, process parameter comparisons, or processing differences for various diamond types is needed, I can continue to supplement.
