MEMS Sensor Particle Filtration for Contamination-Stable Pressure Sensing
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Solution Overview
Problem
MEMS pressure and acceleration sensors are prone to contamination and pollution from external particles and gases, leading to signal drifts and potential membrane destruction, especially in tire-mounted applications.
Innovation Solution
A semiconductor device with a MEMS chip protected by a glass-based substrate featuring perforation holes that act as a filter, combined with a second substrate and recesses to prevent contamination, using methods like LIDE and wet-chemical etching to create these features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an open access is provided to the sensitive membrane for pressure detection, then the sensor can detect pressure differences effectively, but the sensor becomes vulnerable to contamination by particles, gases, and liquids from the environment
Solution Approach 1:
The patent applies a glass-based substrate with a porous structure containing numerous perforation holes. This porous material allows pressure differences to be detected while simultaneously filtering out particles and contaminants from the environment, thus resolving the contradiction between measurement capability and contamination resistance
Solution Approach 2:
The glass-based substrate with perforation holes acts as an intermediary element between the external environment and the sensitive membrane. It mediates the interaction by allowing pressure transmission while blocking harmful particles and contaminants, thus protecting the membrane while maintaining detection functionality
2Device complexity
If particles and contaminants accumulate in the access opening region, then the sensor structure remains simple, but the sensor experiences signal drifts and potential membrane destruction
Solution Approach 1:
The porous glass substrate with controlled perforation holes provides a filtering function that prevents particle accumulation while maintaining structural simplicity. The uniform porous structure filters contaminants before they can reach the sensitive membrane, thus maintaining reliability without significantly increasing device complexity
Solution Approach 2:
The glass-based substrate with perforation holes is positioned in advance to prevent contaminant accumulation before it can cause harm. This preliminary protective action blocks particles and contaminants from reaching the access opening region, preventing signal drifts and membrane destruction before they occur
3Ease of manufacture
If the MEMS chip is directly exposed to the environment for pressure sensing, then the manufacturing process remains simple, but the sensor suffers from membrane sticking and signal offset due to centrifugal force accumulation of contaminants
Solution Approach 1:
The porous glass substrate with perforation holes is integrated into the sensor structure to provide filtration while maintaining manufacturing feasibility. The standardized porous structure allows for efficient production while preventing membrane sticking and signal offset caused by contaminant accumulation under centrifugal force
Solution Approach 2:
The glass-based substrate serves as an intermediary protective layer between the environment and the MEMS chip. It mediates the interaction by filtering contaminants before they can cause membrane sticking or signal offset, thus protecting the sensor while maintaining ease of manufacture through a relatively simple additive 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
The solution effectively filters out contaminants, maintaining sensor reliability and robustness by preventing membrane sticking and signal offset, while allowing for efficient electrical connections and reduced water adhesion.
Implementation Method 1
a first glass-based substrate, on which the MEMS chip is arranged by its first main surface, and a second substrate, which is arranged on the second main surface of the MEMS chip, wherein the MEMS chip has a first recess connected to the surroundings by way of a plurality of perforation holes arranged in the first substrate
Data Source
AI summary
A method for producing a semiconductor device includes providing a microelectromechanical system (MEMS) chip having a first main surface and a second main surface situated opposite the first main surface, wherein the first main surface of the MEMS chip has a recess; providing a first glass-based substrate, wherein the first glass-based substrate has a plurality of perforation holes; applying the first main surface of the MEMS chip onto the first glass-based substrate in such a way that the recess becomes located over the plurality of perforation holes; providing a second substrate, which is arranged on the second main surface of the MEMS chip; and applying the second substrate to the second main surface of the MEMS chip.