MEMS Gas Sensor Mount Body With Capless Cavity Protection
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Solution Overview
Problem
The existing MEMS gas sensor mount bodies are limited in thinning due to the need for a cap to protect the insulating film, which covers the through hole of the base, thereby restricting further reduction in size.
Innovation Solution
A MEMS gas sensor mount body design that eliminates the need for a cap by using a MEMS gas sensor chip with a cavity covered by an insulating film and pads connected through micropores, grooves, or a metal mesh, allowing for easier thinning and protection of the gas sensing unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cap is provided to protect the insulating film covering the through hole, then the insulating film is protected from damage, but the MEMS gas sensor mount body cannot be thinned
Solution Approach 1:
The patent inverts the conventional structure by positioning the gas sensing unit above the cavity rather than having the cavity open to the top surface. The insulating film covers the cavity from below, and the gas sensing unit is protected from above by the base structure itself, eliminating the need for a cap while maintaining protection of the thin insulating film.
Solution Approach 2:
The patent changes the spatial arrangement by creating a cavity that extends downward from the base rather than having an open through hole. The insulating film is formed on the inner surface of the cavity, and the gas sensing unit is positioned above the cavity, utilizing the vertical dimension to achieve both protection and thinning.
2Length of moving object
If the insulating film is made very thin to cover the through hole, then the mount body can be thinned, but the insulating film becomes vulnerable to damage requiring a cap
Solution Approach 1:
Instead of having the insulating film cover an open through hole from one side, the patent inverts the structure so the insulating film lines the cavity from the base side, and the gas sensing unit is protected from the opposite direction by the base structure, allowing the film to be thin without compromising strength.
Solution Approach 2:
The base structure serves as a protective cushion for the thin insulating film by positioning the gas sensing unit above the cavity. The base provides mechanical support and protection before any potential damage can occur to the thin insulating film, eliminating the need for additional protective caps.
3Object-affected harmful factors
If a cap is used to prevent debris and oil from adhering to the gas sensitive material, then the gas sensitive material is protected, but the device complexity increases
Solution Approach 1:
The patent merges the protective function into the base structure itself. The cavity design and positioning of the gas sensing unit above the cavity allow the base to serve both as a structural support and as a protective element, eliminating the need for a separate cap component and reducing overall device complexity.
Solution Approach 2:
The base structure is designed to perform multiple functions: it provides mechanical support, defines the cavity structure, protects the insulating film, and prevents contamination of the gas sensing unit. This multi-functionality eliminates the need for separate protective components.
Data Source
AI summary
A MEMS gas sensor mount body includes a MEMS gas sensor chip and a printed circuit board. The MEMS gas sensor chip includes a base having a cavity, an insulating film having an opening portion, a gas sensing unit, and a plurality of pads. The printed circuit board includes a gas introduction path, and a plurality of connection terminals. The MEMS gas sensor chip is mounted on the printed circuit board to cover the opening portion, with the cavity and the gas introduction path overlapping in plan view, and with the plurality of pads electrically connected to the plurality of connection terminals. The gas introduction path is provided on the printed circuit board in a region other than a region on which the gas sensing unit is positioned.