MEMS Membrane Transducer Gap Design for Stress Reduction
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Solution Overview
Problem
Existing MEMS-transducers face challenges in achieving high robustness against mechanical loads and stresses, particularly due to the lack of effective mechanisms to manage deflection and stress distribution in the membrane structure.
Innovation Solution
The proposed MEMS-transducer incorporates a membrane structure with a substrate structure that overlaps only in a specific edge region, creating a gap between the membrane and the substrate. This gap extends from an inner region to an outer region, allowing for reduced mechanical load during deflection and enhancing robustness. Additionally, a carbon layer is arranged on the membrane surface in an outer region adjacent to the gap, providing further structural support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the substrate structure fully overlaps with the membrane structure for strong mechanical support, then the mechanical strength is improved, but the mechanical stress and peeling forces on the membrane increase during deflection
Solution Approach 1:
The patent segments the overlap region between substrate and membrane into two distinct zones: a first edge region with full overlap for mechanical support, and a second edge region with no overlap (gap) to reduce stress. This spatial segmentation allows different regions to serve different functions - support versus stress reduction.
Solution Approach 2:
The patent applies local quality by providing different structural configurations at different locations of the membrane-substrate interface. The first edge region has substrate overlap for strength, while the second edge region has a gap for stress relief, allowing each local region to optimize for its specific function.
2Strength
If the substrate structure fully overlaps with the membrane structure, then the mechanical support is improved, but the robustness against mechanical load deteriorates due to increased peeling forces
Solution Approach 1:
The overlap region is segmented into two parts: a first edge region providing mechanical support through substrate overlap, and a second edge region providing robustness through a gap that eliminates peeling forces. This segmentation resolves the contradiction between support and robustness.
Solution Approach 2:
Different local configurations are implemented: full substrate overlap in the first edge region for support, and a gap in the second edge region for robustness. This local differentiation allows the structure to simultaneously achieve both mechanical support and high robustness.
3Reliability
If a gap is introduced between the membrane and substrate to reduce mechanical stress, then the robustness is improved, but the structural support is weakened
Solution Approach 1:
The patent segments the edge regions into two zones: one with gap for robustness and one with overlap for structural support. This ensures that introducing a gap does not compromise overall structural integrity, as support is maintained in the overlap region.
Solution Approach 2:
The gap is introduced locally in the second edge region rather than across the entire membrane-substrate interface. This localized gap provides robustness where needed while maintaining structural support in the first edge region through overlap.
Data Source
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AI summary
A MEMS-transducer comprises a membrane structure having a first main surface and a second main surface opposing the first main surface. A substrate structure is configured to hold the membrane structure, wherein the substrate structure overlaps with the first main surface of the membrane structure in a first edge region being adjacent to a first inner region of the first main surface. A gap is formed between the membrane structure and the substrate structure in the first edge region and extends from the first inner region into the first edge region.