Arched MEMS Membrane Structure for Strength and Sensitivity
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Solution Overview
Problem
Existing MEMS devices with flat membranes face challenges in achieving both sensitivity and structural strength, as they are prone to stress and warpage.
Innovation Solution
The formation of an arched opening in MEMS devices through multiple etching processes, which includes a first etching process to reveal a membrane layer and a second etching process to form an arch, enhances the mechanical strength of the membrane and reduces warpage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the membrane is made thinner to improve sensitivity, then sensitivity is improved, but structural strength deteriorates
Solution Approach 1:
The patent applies curvature by forming an arched opening instead of a flat opening in the membrane structure. The arch shape distributes mechanical stress more effectively across the membrane, allowing thinner membranes to maintain both high sensitivity and adequate structural strength. The curved geometry provides inherent mechanical reinforcement without requiring increased material thickness.
2Measurement precision
If the membrane is made thinner to improve sensitivity, then sensitivity is improved, but resistance to stress deteriorates
Solution Approach 1:
The arched opening geometry provides inherent stress distribution that prevents stress concentration in thin membranes. The curvature creates a more robust load path that enhances reliability and stress resistance while maintaining the thin profile needed for sensitivity.
3Ease of manufacture
If a flat membrane structure is used, then manufacturing is simpler, but warpage occurs
Solution Approach 1:
The arched opening design inherently compensates for warpage by pre-establishing a curved stress distribution pattern. This curvature counteracts the natural tendency of thin membranes to warp, providing a self-correcting geometric solution that maintains structural stability.
4Adaptability or versatility
If the opening is made larger to improve membrane performance, then membrane performance is improved, but mechanical strength deteriorates
Solution Approach 1:
The arched opening allows for larger opening dimensions while maintaining mechanical strength through its curved geometry. The arch shape distributes the mechanical loads more effectively across the membrane structure, enabling larger openings without compromising the overall structural integrity.
Data Source
AI summary
A method includes bonding a supporting substrate to a semiconductor substrate of a wafer. A bonding layer is between, and is bonded to both of, the supporting substrate and the semiconductor substrate. A first etching process is performed to etch the supporting substrate and to form an opening, which penetrates through the supporting substrate and stops on the bonding layer. The opening has substantially straight edges. The bonding layer is then etched. A second etching process is performed to extend the opening down into the semiconductor substrate. A bottom portion of the opening is curved.