Stacked Stop Element for MEMS Electrode Protection
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Solution Overview
Problem
MEMS and NEMS devices face challenges with sticking of mobile elements due to Van der Waals forces and electrostatic interactions, leading to potential micro-arcing and damage during vibrations or shocks, especially when elements are close and differently polarized.
Innovation Solution
Implementing an additional electrically insulated layer with mobile elements that are mechanically integral with the primary electrodes, ensuring they do not come into direct contact and are designed to interrupt relative movement before a risky proximity is reached, thereby preventing micro-arcing and maintaining mechanical and electrical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If mobile elements are placed close together to minimize device size, then device miniaturization is achieved, but the risk of electrostatic discharge and micro-arcing increases
Solution Approach 1:
An intermediate stop element is introduced between the first and second mobile elements. This stop element serves as a mediator that prevents direct contact between the differently polarized mobile elements, thereby eliminating the electrostatic discharge pathway while allowing the elements to remain in close proximity for miniaturization
Solution Approach 2:
The mobile element is segmented into multiple parts: the first mobile element, the stop element, and the second mobile element. This segmentation allows the stop element to be positioned between the other two elements, physically separating them and preventing direct contact while maintaining compact overall dimensions
2Strength
If abutment elements are implemented to prevent contact between mobile elements, then mechanical strength is improved, but electrostatic discharge risk remains if stops are electrically connected to mobile elements
Solution Approach 1:
The stop element acts as an electrical intermediary that is mechanically connected to both mobile elements but electrically isolated from them. This allows the stop element to provide mechanical support and prevent contact while breaking the electrical pathway that would enable electrostatic discharge
Solution Approach 2:
The electrical connection between mobile elements is replaced with a mechanical connection through the stop element. The stop element provides mechanical support and positioning without creating an electrical pathway, substituting the mechanical function for the electrical connection that would otherwise exist
3Volume of moving object
If mobile elements are made fragile to achieve miniaturization, then device size is reduced, but vulnerability to damage from vibrations or shocks increases
Solution Approach 1:
The stop element is positioned in advance between the mobile elements to cushion them against each other during vibrations or shocks. This pre-positioned element absorbs and distributes mechanical stresses before they can reach the fragile mobile elements, protecting them from damage while allowing miniaturized dimensions
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 solution effectively prevents direct contact and electrostatic discharge between differently polarized elements, ensuring the mechanical and electrical integrity of the devices even during vibrations or shocks, while minimizing risks associated with electrostatic interactions in miniaturized devices.
Implementation Method 1
One of the main failure modes of MEMS or NEMS electromechanical devices is the sticking of mobile elements, in particular by Van der Waals forces
Implementation Method 2
electrostatic interaction of differently polarized mobile elements
Implementation Method 3
bringing a stop having a certain polarity into contact with an element of different polarity can generate a through current and an electrostatic discharge
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
The invention relates to a sensor-type or actuator-type MEMS or NEMS device provided with a stacked stop element comprising - a first flat layer having a first flat electrode intended to be at a first electric potential and a second flat electrode intended to be at a second electric potential different from the first potential, said first flat electrode being movable relative to the second flat electrode in a first direction parallel to the first flat layer, - a second flat layer placed on top of the first flat layer and electrically insulated from the first flat layer by at least one intermediate layer made of an insulating material, the second flat layer comprising a first flat element that is mechanically secured to the first flat electrode, and a second flat element that is mechanically secured to the second flat electrode, characterized in that it further comprises at least one stop element extending from the first flat element or the second flat element in the first direction and projecting from said flat element in the first direction, the stop element extending from one of the flat elements being intended to be at the same potential as an opposite surface belonging to the other flat element, and the stop element and the electrodes further being designed for the stop element to come into contact with the opposite surface and to stop the two flat electrodes from moving towards each other in the first direction when under stress.