MEMS Bumper Offset Design for Stiction Resistance
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Solution Overview
Problem
Micro-Electro-Mechanical System (MEMS) switches face issues with actuated stiction due to residual stress variability, temperature-induced changes, and process variations, leading to misalignment of bumpers with dummy landing structures, which affects the reliability and lifetime of MEMS beams.
Innovation Solution
A method is developed to design and manufacture MEMS structures with a dummy landing structure that is laterally offset from the bumper, taking into account process variations and operating conditions, ensuring alignment with the bumper at any given operating temperature, thereby compensating for stress and temperature-induced changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the dummy landing structure is aligned with the bumper at the nominal position, then the manufacturing process is simple, but residual stress variability and temperature-induced changes cause misalignment and stiction
Solution Approach 1:
The dummy landing structure is deliberately positioned at an offset location during manufacturing, anticipating the beam's lateral displacement caused by residual stress and temperature changes. This preliminary positioning ensures that when the beam actuates, the bumper will align with the dummy landing structure despite process variations and thermal effects.
Solution Approach 2:
The design accounts for parameter changes in beam position due to residual stress and temperature by incorporating an offset in the dummy landing structure's position. This offset compensates for the expected displacement, maintaining alignment under varying operating conditions.
2Reliability
If the dummy landing structure is offset from the bumper, then alignment is maintained under process variations and temperature changes, but the structure becomes more complex
Solution Approach 1:
The dummy landing structure's position is adjusted by an offset parameter that compensates for beam displacement due to residual stress and temperature. This single parameter change maintains alignment without requiring complex active control systems.
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
This approach significantly improves the resistance to actuated MEMS beam stiction, resulting in a factor of 5× improvement in actuated beam lifetime by ensuring proper alignment of the bumper with the dummy landing structure, even under varying operational conditions.
Implementation Method 1
The voltage required to pull the suspended electrode to the fixed electrode by electrostatic force is called pull-in voltage
Implementation Method 2
temperature-induced changes, and process variations, leading to misalignment of bumpers with dummy landing structures
Data Source
AI summary
Dummy Micro-Electro-Mechanical System (MEMS) structures, methods of manufacture and design structures are disclosed. The method includes forming a bumper extending from a Micro-Electro-Mechanical System (MEMS) beam structure provided within a cavity structure. The method further includes forming a dummy landing structure on an opposing side of the cavity structure from the MEMS beam, which is laterally offset from the bumper when the MEMS beam is in a non-actuated state.