MEMS Microphone Package Structure for Miniaturization
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Solution Overview
Problem
The miniaturization of MEMS microphone package structures leads to a reduction in the volume ratio of the back chamber to the front chamber, adversely affecting the sensitivity of the microphone, as the total thickness of the package is reduced to meet miniaturization demands.
Innovation Solution
The MEMS package structure incorporates a first substrate with a through hole and a transducer unit, where the transducer unit includes a base and a membrane located between the through hole and the base, and a second substrate attached to the first substrate defining a cavity, allowing the transducer unit and semiconductor chip to be disposed in the cavity, thereby maintaining a large volume ratio of the back chamber to the front chamber even with reduced total thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the total thickness of the MEMS package structure is reduced to meet miniaturization demands, then the device size is reduced, but the volume of space between the substrate and the lid is reduced, adversely affecting the sensitivity of the MEMS microphone
Solution Approach 1:
The patent transitions from a conventional single-substrate planar layout to a three-dimensional stacked architecture with multiple substrates (first substrate, second substrate, lid) arranged in vertical layers. This dimensional reorganization allows the back chamber to extend through multiple substrate layers, effectively increasing the back chamber volume without increasing the horizontal footprint or overall package thickness, thereby resolving the contradiction between miniaturization and sensitivity.
Solution Approach 2:
The patent implements a nested structure where the first substrate contains a through-hole, the second substrate is positioned within the cavity formed by the first substrate, and the transducer unit is nested within the back chamber. The multiple substrates and chambers are arranged in concentric, space-efficient configurations that maximize the back chamber volume within the constrained package thickness, maintaining sensitivity while achieving miniaturization.
2Volume of stationary object
If the volume ratio of the back chamber to the front chamber is maintained, then the sensitivity of the MEMS microphone is improved, but the total thickness of the package structure increases
Solution Approach 1:
The patent divides the package structure into multiple functional segments: first substrate with through-hole, second substrate with cavity, lid, transducer unit, back chamber, and front chamber. Each segment is optimized independently to contribute to the overall back chamber volume while maintaining compact thickness. The segmentation allows the back chamber to utilize space across multiple substrate layers, achieving high volume ratio without proportionally increasing total thickness.
Solution Approach 2:
The patent extends the back chamber volume in the vertical dimension by arranging multiple substrates and chambers in a stacked configuration. The back chamber spans across the first substrate, second substrate, and lid layers, effectively utilizing the vertical space to increase volume without increasing the horizontal footprint. This dimensional approach allows maintaining high sensitivity while controlling package thickness.
Data Source
AI summary
A microelectromechanical systems package structure includes a first substrate, a transducer unit, a semiconductor chip and a second substrate. The first substrate defines a through hole. The transducer unit is electrically connected to the first substrate, and includes a base and a membrane. The membrane is located between the through hole and the base. The semiconductor chip is electrically connected to the first substrate and the transducer unit. The second substrate is attached to the first substrate and defines a cavity. The transducer unit and the chip are disposed in the cavity, and the second substrate is electrically connected to the transducer unit and the semiconductor chip through the first substrate.