MEMS Suspended Structure Layout to Prevent Electrostatic Stiction
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Solution Overview
Problem
MEMS devices face adhesion failures due to surface contact during motion, particularly in structures driven by static electricity, leading to functional failures.
Innovation Solution
The MEMS device design includes a first dielectric substrate with a first component that encloses a movable space, featuring protruding structures and openings arranged to prevent overlap and ensure the protruding structures' thickness is less than the movable space, formed through dry etching of a sacrificial layer using the component as a mask.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a suspending structure is driven by static electricity, then the device achieves actuation function, but surface contact and adhesion effect occur during motion
Solution Approach 1:
The patent applies curvature by forming protruding structures with rounded tips on the movable component. These curved protruding structures reduce the contact area and adhesion force between the movable component and the substrate during actuation, preventing stiction while maintaining the electrostatic actuation function.
Solution Approach 2:
The patent implements local quality by creating protruding structures at specific locations on the movable component where contact with the substrate is most likely to occur. These localized protruding structures modify the contact characteristics only in critical areas, preventing adhesion failure without affecting the overall actuation performance.
2Ease of manufacture
If the movable component is designed with simple structure, then manufacturing is easier, but adhesion failure occurs due to surface contact
Solution Approach 1:
The patent applies segmentation by dividing the movable component into regions with protruding structures and regions without. The protruding structures are formed by etching patterns on the movable component, creating a segmented structure that prevents adhesion in critical contact areas while maintaining simplicity in other areas. This segmented approach balances manufacturing ease with reliability.
3Reliability
If protruding structures are added to prevent adhesion, then reliability improves, but device complexity increases
Solution Approach 1:
The patent implements the taking out principle by removing material to form protruding structures on the movable component. These protruding structures are created by etching patterns that extract material from the movable component, forming three-dimensional features that prevent adhesion. This approach adds functionality without significantly increasing overall device complexity.
Solution Approach 2:
The patent applies preliminary action by forming the protruding structures during the manufacturing process before the device is assembled and operated. The protruding structures are created through etching patterns on the movable component during fabrication, ensuring adhesion prevention is built into the device structure from the beginning rather than requiring additional assembly steps.
4Manufacturing precision
If dry etching process is used to form protruding structures, then manufacturing precision improves, but process complexity increases
Solution Approach 1:
The patent replaces mechanical drilling or punching methods with a dry etching process to form protruding structures. The dry etching process uses chemical reactions to precisely remove material and create the desired three-dimensional protruding structures, achieving high manufacturing precision while avoiding complex mechanical tooling and assembly operations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents adhesion of the movable components to the substrate, enhancing the reliability and reducing failure risks in MEMS devices by minimizing contact area and utilizing cost-effective manufacturing processes.
Implementation Method 1
the sacrificial layer is etched by using dry etching to form the at least one protruding structure
Implementation Method 2
the suspending structure driven by static electricity may generate a surface contact in the motion process
Data Source
AI summary
The present disclosure provides an MEMS device, a method for manufacturing an MEMS device and an electronic device, and belongs to the field of Micro-Electro-Mechanical System technology. The MEMS device includes: a first dielectric substrate and a first component on the first dielectric substrate; the first component and the first dielectric substrate enclose a movable space; the first component has a first portion corresponding to the movable space; the first portion has at least one first opening, and at least one protruding structure is on a side of the first portion close to the first dielectric substrate; orthographic projections of the at least one protruding structure and the at least one first opening on the first dielectric substrate do not overlap with each other, and a thickness of each protruding structure is smaller than a height of the movable space.