Dual Substrate MEMS Plate Switch for Compact Durability
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Solution Overview
Problem
Existing microelectromechanical systems (MEMS) switch devices, particularly those with cantilevered designs, face challenges in durability and compactness due to the need for a thin, delicate upper substrate that is susceptible to damage and limited in spacing and flexibility, which affects the stiffness and placement of switch contacts.
Innovation Solution
The development of an electrostatic MEMS plate switch using dual substrates, where a deformable plate with shunt bars is formed on one substrate and electrical contacts on another, allowing for a hermetic seal and flexible spring beams to support the plate, enabling stronger restoring forces and compact design without impacting plate dimensions, and allowing multiple switches on a single plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a thin upper substrate is used to enable electrostatic deflection, then the switch can be activated, but the substrate becomes delicate and susceptible to damage
Solution Approach 1:
The device is divided into two separate substrates: a first substrate that provides mechanical support and a second substrate that is thin and movable. This segmentation allows the thin substrate to be flexible enough for actuation while the thicker first substrate provides durability and protection against damage.
2Ease of operation
If the upper substrate is made thin for moveability, then electrostatic deflection is enabled, but the spacing and placement of switch contacts is limited
Solution Approach 1:
By separating the device into two substrates, the design decouples the mechanical support function from the movable contact function. This allows the second substrate to be thin for deflection while the first substrate can accommodate various contact spacings and configurations without compromising structural integrity.
3Ease of operation
If a cantilevered beam design is used, then the switch can function, but the device size is increased and compactness is reduced
Solution Approach 1:
The invention transitions from a traditional cantilevered beam design to a parallel plate configuration where the movable contact is a plate parallel to the fixed substrate. This dimensional change allows for a more compact arrangement, reducing the overall device volume while maintaining switching functionality through electrostatic attraction between the parallel plates.
4Speed
If the restoring force stiffness is increased, then the switch response is improved, but the plate dimensions must be reduced
Solution Approach 1:
The patent allows for adjustment of the restoring force stiffness by modifying parameters such as the spring constant of the support structure or the electrostatic field strength, independent of plate dimensions. This enables optimization of switch response speed without necessarily reducing plate size, as the stiffness can be tuned through material properties or geometric parameters of the support structure.
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 design enhances the durability and compactness of the MEMS switch, providing adjustable stiffness, increased spacing options for contacts, and improved resistance to vibrations and contamination, while maintaining high switching speed and reliability across a wide frequency range.
Implementation Method 1
an electrostatic electrode disposed adjacent to the deformable plate and on the second substrate. Upon applying a voltage between the deformable plate and the electrostatic electrode, the electrostatic force deforms the deformable plate
Data Source
AI summary
Systems and methods for forming an electrostatic MEMS plate switch include forming a deformable plate on a first substrate, forming the electrical contacts on a second substrate, and coupling the two substrates using a hermetic seal. The deformable plate may have at least one shunt bar located at a nodal line of a vibrational mode of the deformable plate, so that the shunt bar remains relatively stationary when the plate is vibrating in that vibrational mode. The hermetic seal may be a gold/indium alloy, formed by heating a layer of indium plated over a layer of gold. Electrical access to the electrostatic MEMS switch may be made by forming vias through the thickness of the second substrate.