MEMS Sensor Stress Decoupling Trenches
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Solution Overview
Problem
Mechanical stress transferred through chip packaging can cause offset, linearity, and hysteresis errors in MEMS pressure sensors, leading to incorrect measurements due to deformation of the sensor housing and stress components at the sensor surface.
Innovation Solution
A semiconductor device with a stress-relief mechanism featuring stress-decoupling trenches and particle filter trenches integrated into the substrate, which decouple mechanical stress from the MEMS element and protect against foreign particles, ensuring accurate sensor functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chip packaging is used to protect and mount the MEMS sensor, then the sensor is protected and mounted securely, but mechanical stress is transferred through the package to the sensor causing offset, linearity, and hysteresis errors
Solution Approach 1:
The substrate is segmented by creating stress-decoupling trenches that divide the continuous substrate into isolated regions. These trenches physically separate the sensor area from stress propagation paths, allowing the package to remain intact for protection while preventing stress transfer to the sensor element.
Solution Approach 2:
The stress-decoupling trenches act as intermediary structures between the package and the sensor. They serve as stress barriers that intercept and block mechanical stress before it reaches the sensor, while still allowing the package to fulfill its protective and mounting functions.
2Measurement precision
If stress-decoupling trenches are introduced to protect the sensor from mechanical stress, then measurement precision is improved, but device complexity and manufacturing steps increase
Solution Approach 1:
The substrate is segmented by creating stress-decoupling trenches that divide the continuous substrate into isolated regions. These trenches physically separate the sensor area from stress propagation paths, allowing the package to remain intact for protection while preventing stress transfer to the sensor element.
Solution Approach 2:
The stress-decoupling structure utilizes a trench-based porous or cavity structure in the substrate. This approach creates stress-blocking regions without requiring complete removal of material or complex multi-layer structures, simplifying manufacturing while maintaining stress isolation effectiveness.
3Measurement precision
If stress-decoupling trenches extend completely through the substrate, then stress isolation is maximized, but manufacturing complexity and risk of substrate damage increase
Solution Approach 1:
Instead of creating complete through-trenches, the patent applies partial action by extending stress-decoupling trenches only to a sufficient depth to block stress propagation paths. This partial depth is determined by stress analysis to be adequate for isolation, avoiding the excessive action of complete through-substrate trenching and its associated manufacturing risks.
Solution Approach 2:
The trench depth is carefully controlled to provide sufficient stress isolation while maintaining substrate integrity. This prior cushioning approach ensures that the substrate is not over-stressed during manufacturing, preventing damage while achieving the necessary stress decoupling effect.
Data Source
AI summary
A semiconductor device and a method of manufacturing the same are provided. The semiconductor device includes a substrate having a first surface and a second surface arranged opposite to the first surface; a stress-sensitive sensor disposed at the first surface of the substrate, where the stress-sensitive sensor is sensitive to mechanical stress; a stress-decoupling trench that has a vertical extension that extends from the first surface into the substrate, where the stress-decoupling trench vertically extends partially into the substrate towards the second surface although not completely to the second surface; and a plurality of particle filter trenches that vertically extend from the second surface into the substrate, wherein each of the plurality of particle filter trenches have a longitudinal extension that extends orthogonal to the vertical extension of the stress-decoupling trench.