This invention enables the creation of hinged MEMS diaphragms with deep comb fins that provide high capacitance and strong mechanical stability. A controlled release sequence protects fragile structures during fabrication, resulting in more reliable devices with higher sensitivity, reduced damping, and improved performance for advanced sensing and actuation applications.
Background:
MEMS devices that rely on out of plane rotational motion often suffer from low capacitance, high viscous damping, and structural failure during fabrication. Shallow comb fingers limit sensitivity and parallel plate designs are prone to collapse under bias. In addition, stress during processing can crack thin hinge supports, reducing device reliability and manufacturing yield. Existing fabrication methods cannot produce deep, robust comb fins while preserving delicate structures. A solution that improves capacitance, reduces damping, and enhances fabrication reliability is needed for high-performance MEMS devices.
Technology Overview:
The invention forms trenches in a substrate, coats them with a sacrificial layer, and deposits a structural layer that extends into the trenches. The structural layer is patterned to create a hinged diaphragm with deep interdigitated comb fins and stiffeners. During release, the sacrificial material under the planar structure is removed first while the sacrificial material in the trench region remains temporarily to support fragile features. This timed sequence enables successful release of deep fins and hinges, producing a robust, high aspect ratio structure with improved capacitance and stiffness. The method ensures reliable fabrication of complex MEMS geometries with enhanced performance characteristics.
Advantages:
• High aspect ratio deep fins increase capacitance and sensing performance • Reduced air damping using interdigitated comb structures • Improved mechanical stiffness and hinge protection during fabrication • Sequential sacrificial release improves yield and avoids cracking • Higher bias voltage tolerance without collapse • More linear capacitance change through overlap modulation
Applications:
• Directional acoustic sensing • MEMS micromirrors for optical systems and LiDAR • High fidelity directional MEMS microphones • MEMS resonators and timing components • MEMS RF switches • Precision micro actuators for microfluidics • MEMS energy harvesters
Intellectual Property Summary:
• United States 9,554,213 • United States 9,906,869
Stage of Development:
Prototype
Licensing Status:
This technology is available for licensing.
Licensing Potential:
Strong potential for MEMS manufacturers, sensor developers, and microfabrication companies seeking high-sensitivity, reliable, and scalable solutions for advanced sensing, actuation, and RF applications.
Additional Information:
Information available upon request.
Inventors: Ronald Miles, Weili Cui
Alternate NCS Title: Robust High Sensitivity Mems Diaphragm Using Deep Comb Fins and Controlled Release Fabrication