Integrated MEMS Microphone and Pressure Sensor on Shared Substrate
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Solution Overview
Problem
The existing packaging process for MEMS microphones and pressure sensors on PCBs is limited in reducing the size of electronic components, making it difficult to meet the size requirements for consumer electronics.
Innovation Solution
A manufacturing method that integrates a MEMS microphone and a pressure sensor on a shared substrate by depositing insulating and polycrystalline silicon layers, etching to form vibrating diaphragms and electrodes, and eroding sacrificial layers to create cavities, allowing for shared material and process usage and reduced overall size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure sensor and a MEMS microphone are packaged on a PCB as two independent single bodies, then the packaging process is mature and reliable, but the size of the product becomes larger
Solution Approach 1:
The patent combines the pressure sensor and MEMS microphone into a single integrated structure by forming both devices on the same substrate. The substrate includes a first cavity for the pressure sensor and a second cavity for the MEMS microphone, with both devices sharing common structural elements and processing steps, thereby reducing overall product size while maintaining packaging reliability
Solution Approach 2:
The substrate serves multiple functions simultaneously: it acts as the base for both the pressure sensor and MEMS microphone, provides structural support for both devices, and contains both cavities. This multi-functional design eliminates the need for separate packaging structures, reducing size while preserving process maturity
2Manufacturing precision
If the process capability approaches the limit to further reduce chip size, then manufacturing precision is maintained, but the ability to reduce size further is constrained
Solution Approach 1:
By integrating both sensors on a single substrate using unified processing steps (depositing layers, forming cavities, creating electrodes), the patent achieves size reduction without requiring beyond-current manufacturing capabilities. The shared substrate and common processing maintain precision while enabling compact form factor
3Adaptability or versatility
If two independent sensors are packaged separately, then each sensor can be optimized independently, but production efficiency decreases
Solution Approach 1:
The patent enables simultaneous fabrication of both pressure sensor and MEMS microphone on the same substrate through coordinated processing steps. Different regions of the substrate are patterned and processed to create both devices, allowing parallel production that improves efficiency while maintaining independent optimization capability through region-specific design
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
This method enables the integration of MEMS microphone and pressure sensor capacitance structures on a shared substrate, significantly reducing the size of the packaging structure and improving production efficiency while maintaining functionality.
Implementation Method 1
depositing an insulating layer and a first polycrystalline silicon layer in sequence on a shared substrate of the MEMS microphone and the pressure sensor
Implementation Method 2
eroding parts of the sacrificial layer to form containing a cavity of the MEMS microphone and a cavity of the pressure sensor
Data Source
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AI summary
The present invention discloses a manufacturing method of an integrated structure of a MEMS microphone and a pressure sensor, which comprises the following steps: depositing an insulating layer, a first polycrystalline silicon layer, a sacrificial layer and a second polycrystalline silicon layer in sequence on a shared substrate; etching the second polycrystalline silicon layer to form a vibrating diaphragm and an upper electrode; eroding the sacrificial layer to form a containing cavity of a microphone and a pressure sensor, and etching the sacrificial layer between the microphone and the pressure sensor; etching the first polycrystalline silicon layer to form a back electrode of the microphone and a lower electrode of the pressure sensor; etching a position of the shared substrate below a back electrode of the microphone to form a back cavity; and etching away the region of the insulating layer below the back electrode. A capacitance structure of a MEMS microphone and that of a pressure sensor are integrated on a shared substrate, improving integration of a MEMS microphone and a pressure sensor, and greatly reducing a size of a whole packaging structure; in addition, a microphone and a pressure sensor can be simultaneously manufactured on a shared substrate to improve the efficiency of production.