Segmented MEMS Electrode for Stress-Induced Bending
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Solution Overview
Problem
The existing MEMS devices with movable electrodes suffer from reduced capacitance density and tuning range due to stress differences between the mechanical and intermediate layers, leading to bending of the second electrode and decreased effective contact area.
Innovation Solution
The second electrode is segmented into independent sections with separate vertical interconnects to the mechanical layer, reducing stress and bending, and enhancing capacitance density, while allowing for independent optimization of the front and back ends of the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the second electrode is made as a single continuous layer in the intermediate layer, then the mechanical stability is maintained, but the stress difference between layers causes bending of the electrode, reducing the effective contact area and capacitance density
Solution Approach 1:
The second electrode is divided into multiple independent sections within the intermediate layer, each connected to the mechanical layer by separate vertical interconnects. This segmentation prevents stress-induced bending by isolating each section, allowing them to maintain planarity independently while collectively forming the complete electrode structure.
2Stability of the object's composition
If the vertical interconnect diameter is reduced to minimize stress, then the bending is reduced, but the mechanical strength of the connection may be compromised
Solution Approach 1:
The vertical interconnects are designed with optimized local dimensions where the diameter is specifically sized to balance stress reduction with mechanical strength requirements. The interconnect structure may vary in cross-section or material properties at different locations to simultaneously achieve minimal bending and sufficient connection strength.
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 configuration increases capacitance density, improves thermal stability, and allows for miniaturization of the device, while reducing actuation voltage and damping, thereby enhancing the performance and competitiveness of the MEMS element as a tunable capacitor or switch.
Implementation Method 1
there is a stress difference built up between the mechanical layer and the intermediate layer, even in the case that these layers comprise the same metal or alloy
Implementation Method 2
each of which is mechanically connected by a separate vertical interconnect to the mechanical layer
Implementation Method 3
the first electrode does not make electrical contact with the second electrode in its closed position, but forms a capacitor therewith
Data Source
AI summary
The electronic device comprising a micro-electromechanical systems (MEMS) element at a first side of a substrate. The MEMS element includes a first electrode and a second electrode, that is part of a movable element and movable towards and from the first electrode between a first and a second position. The second electrode is separated from the first electrode by an air gap in its first position. The movable element includes a mechanical layer and an intermediate layer, in which the second electrode is defined. The second electrode is constituted by a plurality of sections in the intermediate layer, each of which is mechanically connected by a separate vertical interconnect to the mechanical layer.