MEMS (Micro-Electro-Mechanical Systems) fabrication requires ultra-fine feature processing at micron scale. Laser etching for MEMS is a non-contact subtractive manufacturing technique that uses focused high-energy laser beam to selectively ablate substrate materials, forming precise microstructures without physical cutting force. It is widely used for rapid prototyping and low-to-medium volume production of MEMS devices, complementing traditional photochemical etching and deep reactive ion etching.

Process Flow

1. Substrate preparation: Clean silicon, glass, quartz or metal wafer to remove surface contaminants.
2. CAD pattern programming: Import MEMS design drawing into laser control system, set laser power, pulse frequency and scanning speed.
3. Laser ablation: Focused laser scans the workpiece surface, vaporizes or melts targeted material to create micro channels, cavities and alignment marks.
4. Post-treatment: Ultrasonic cleaning to remove residual debris; optional surface polishing to reduce edge burrs.
5. Inspection: Use microscope and profilometer to verify feature size, depth and surface roughness.

Core Advantages

1. Non-contact processing: No mechanical stress on delicate thin substrates, avoiding deformation and cracking of fragile MEMS wafers.
2. High flexibility: Quick pattern change by updating digital files, ideal for MEMS R&D prototype iteration.
3. Wide material compatibility: Works with silicon, borosilicate glass, fused silica, stainless steel and nickel thin sheets.
4. Fine micro features: Achieve micron-level line width, suitable for micro channels, diaphragm patterns and alignment markers.
5. No mask required: Save photomask cost and lead time for small batch MEMS development.

Application Fields

• MEMS pressure sensors, acceleration sensors and gyroscope micro structural parts
• Microfluidic chips for biomedical MEMS
• MEMS optical switches and optical attenuator components
• Micro nozzles and micro filters for MEMS aerosol devices
• Wafer alignment marks and packaging interconnection structures

Design Considerations

1. Laser etching has thermal-affected zone on material edge; avoid ultra-fine dense structures that are sensitive to heat.
2. Feature depth control depends on laser parameters; deep through structures usually require multi-pass scanning.
3. For mass production of high-density MEMS arrays, DRIE or photochemical etching often delivers better uniformity than laser etching.
4. Material thickness will limit minimum achievable line width; thin substrates perform better for micro patterns.