Sensor Module Dual Cavity Back Volume Design
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Solution Overview
Problem
Existing sensor modules, particularly micro-electro-mechanical microphones, face challenges in maximizing sensitivity without increasing the height or active membrane area, as the back volume directly impacts the sensitivity and signal-to-noise ratio.
Innovation Solution
The introduction of a second cavity in fluid connection with the first cavity, formed by recesses on the semiconductor chip, which can be hermetically sealed or not, allows for increased back volume without heightening the sensor module, achieved through etching processes and specific recess designs that maintain or enhance the membrane's functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the back volume is increased to improve sensitivity and signal-to-noise ratio, then the sensitivity improves, but the overall module height increases
Solution Approach 1:
The patent transitions from a single-cavity design to a dual-cavity configuration, utilizing the third dimension (depth) more effectively. The first cavity is formed in the semiconductor chip and the second cavity is formed in the carrier, creating a stacked arrangement that increases back volume without proportionally increasing the overall height. This dimensional optimization allows the back volume to expand while maintaining compact module dimensions.
Solution Approach 2:
The patent implements a nested cavity structure where the first cavity (in the semiconductor chip) and second cavity (in the carrier) are positioned to overlap or nest vertically. The recess in the semiconductor chip and the recess in the carrier are aligned to create an integrated back volume that is more space-efficient than separate cavities, thereby increasing back volume without linearly increasing module height.
2Measurement precision
If the back volume is increased by enlarging the active membrane area, then the sensitivity improves, but the device area increases
Solution Approach 1:
Instead of increasing the membrane area in the planar direction (two dimensions), the patent exploits the vertical dimension by creating deep recesses in both the semiconductor chip and carrier. This allows the back volume to increase primarily in the depth direction, enabling sensitivity improvement without expanding the device footprint.
Solution Approach 2:
The back volume is segmented into two distinct cavities: the first cavity formed in the semiconductor chip and the second cavity formed in the carrier. This segmentation allows the back volume to be distributed across multiple components, increasing total back volume without requiring a single large membrane area, thereby maintaining compact device dimensions.
3Measurement precision
If a second cavity is added to increase back volume, then the sensitivity improves, but the device complexity increases
Solution Approach 1:
The carrier serves multiple functions: it provides mechanical support for the semiconductor chip, forms the second cavity to increase back volume, and provides the recess that couples with the chip recess. By making the carrier multi-functional, the patent avoids adding separate components for each function, thereby reducing overall device complexity despite the dual-cavity configuration.
Solution Approach 2:
The patent merges the formation of the two cavities into an integrated structure where the recess in the semiconductor chip and the recess in the carrier work together as a unified back volume system. The coupling channel connects these cavities, creating a seamless fluid communication path that functions as a single integrated acoustic volume rather than two separate systems, thereby simplifying the overall device architecture.
Data Source
AI summary
A sensor module and semiconductor chip. One embodiment provides a carrier. A semiconductor chip includes a first recess and a second recess and a main surface of the semiconductor chip. The semiconductor chip is mounted to the carrier such that the first recess forms a first cavity with the carrier and the second recess forms a second cavity with the carrier. The first cavity is in fluid connection with the second cavity.