MEMS Switch Beam Anchor Design for Thermal Distortion Control
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Solution Overview
Problem
Micro-electro-mechanical systems (MEMS) devices experience distortion due to thermal expansion differences between materials like gold and silicon, leading to performance issues and potential device failure, particularly when subjected to high temperatures during manufacturing and operation.
Innovation Solution
Incorporating voids in the anchor behind the hinge and reducing the anchor's mass, along with using cross connection members and anchor slots, to minimize thermal expansion effects and maintain structural integrity and alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the MEMS device is made from gold and silicon to achieve good electrical conducting properties and integrated circuit fabrication suitability, then the device can be manufactured with standard processes, but thermal expansion differences cause distortion in the structure when subjected to excessive heat
Solution Approach 1:
The patent applies local quality by creating a non-uniform anchor structure with varying thickness. The anchor is thicker at certain regions and thinner at others, specifically designed to compensate for thermal expansion differences between gold and silicon. This localized structural variation allows different parts of the anchor to expand differently, counteracting the overall thermal distortion and maintaining beam alignment during temperature changes.
2Stability of the object's composition
If the anchor mass is reduced and voids are incorporated to minimize thermal expansion effects, then beam distortion is reduced, but the structural strength and rigidity of the anchor may be compromised
Solution Approach 1:
The patent incorporates voids or porous regions within the anchor structure. These voids reduce the overall mass of the anchor while strategically positioned to maintain structural integrity. The voids allow for thermal expansion compensation without significantly compromising the anchor's strength, as the remaining material is distributed to provide necessary structural support while enabling controlled thermal deformation.
3Stress or pressure
If the beam is allowed to deflect freely to accommodate thermal expansion, then thermal stress is reduced, but the tip contact precision and switching performance deteriorate
Solution Approach 1:
The patent explicitly utilizes thermal expansion principles by designing the anchor with specific geometric features that expand or contract in response to temperature changes. The anchor's non-uniform structure is engineered to expand in a controlled manner that compensates for the beam's thermal deflection, thereby maintaining the tip's contact precision with the drain while accommodating thermal stress through controlled expansion rather than unrestricted deflection.
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
The solution effectively reduces distortion and mechanical stress in MEMS devices, ensuring consistent operation and preventing electrical short-circuits by allowing for thermal expansion while maintaining structural stability and alignment.
Implementation Method 1
When subject to excessive heat, the gold and silicon from which a MEMS device are made expand at different rates, which can cause distortion in the structure of the MEMS device
Data Source
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AI summary
Disclosed is a micro-electro-mechanical switch, including a substrate having a gate connection, a source connection, a drain connection and a switch structure, coupled to the substrate. The switch structure includes a beam member, an anchor, an anchor beam interface and a hinge. The beam member having a length sufficient to overhang both the gate connection and the drain connection. The anchor coupling the switch structure to the substrate. The anchor beam interface coupling the anchor to the hinge. The hinge coupling the beam member to the anchor at a respective position along the anchor's length, the hinge to flex in response to a voltage differential established between the gate and the beam member. The switch structure having gaps between the substrate and the anchor in regions proximate to the hinges.