MEMS Physical Quantity Sensor with Shield Layer Observation Space
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Solution Overview
Problem
Existing physical quantity sensors using MEMS technology face challenges in nondestructively observing and confirming defects in minute structures while maintaining a shield effect, as the shield structure prevents visual inspection and can lead to noise interference and water intrusion issues.
Innovation Solution
A physical quantity sensor with a two-layer structure featuring a fixed substrate and an electrode substrate, where a shield layer with an inside observation space is formed around the surface electrodes to block electromagnetic noise and allow for nondestructive observation of the internal structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a shield structure is formed to surround the detecting element, then noise shielding effect is improved, but the ability to observe and confirm defects in the minute structure deteriorates
Solution Approach 1:
The shield structure is segmented into multiple parts: a first shield portion surrounding the detecting element, a second shield portion surrounding the through wiring, and a third shield portion on the surface electrode. This segmentation allows different regions to serve different functions - noise shielding and defect observation - simultaneously, resolving the contradiction between shielding effectiveness and observability.
2Difficulty of detecting and measuring
If a through hole is formed for observation, then defect confirmation is improved, but water intrusion risk and wiring deterioration increase
Solution Approach 1:
Instead of forming a physical through hole that compromises structural integrity, the invention extracts the shielding function from the observation function. The shield structure includes transparent or semi-transparent portions that allow optical observation without creating physical openings, thereby maintaining water tightness while enabling defect confirmation.
3Object-affected harmful factors
If a complete shield layer is formed on the electrode substrate surface, then noise shielding is improved, but the ability to nondestructively observe internal structure deteriorates
Solution Approach 1:
The shield layer exhibits local quality variations: it is formed in regions requiring noise shielding while being omitted or made transparent in regions requiring observation. This spatial differentiation of shield layer properties allows simultaneous achievement of noise protection and optical access without compromising either function.
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 enables the removal of noise and confirmation of defects in the sensor structure, providing a highly reliable physical quantity sensor with improved accuracy and reduced risk of water intrusion.
Implementation Method 1
a shield layer formed on an electrode substrate surface with a plan view, wherein an inside observation space is provided in the shield layer
Implementation Method 2
Such a minute movable structure can be driven by a static electricity
Data Source
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AI summary
For a small sensor produced through a MEMS process, when an electrode pad, wiring, or a shield layer is formed in a final step, it is difficult to nondestructively investigate whether a structure for sensing a physical quantity has been processed satisfactorily. In the present invention, in a physical quantity sensor formed from an MEMS structure, in a structure in which a surface electrode having through wiring is formed on the surface of an electrode substrate and the periphery thereof is insulated, forming a shield layer comprising a metallic material on the surface of the electrode substrate in a planar view and providing a space for internal observation inside the shield layer makes it possible to check for internal defects.