Single-Substrate MEMS Microphone and Accelerometer Integration
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Solution Overview
Problem
The existing method of fabricating MEMS devices separately increases time, cost, and complexity, and can cause damage due to multiple bonding processes, reducing the structural integrity of MEMS devices.
Innovation Solution
Concurrently forming a first MEMS device, such as a microphone, and a second MEMS device, such as an accelerometer, on a single substrate, reducing the number of processing steps and bonding processes, and enhancing structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If MEMS devices are fabricated separately on different substrates, then each device can be optimized independently, but the fabrication time, cost, and complexity increase due to multiple bonding processes
Solution Approach 1:
The patent combines multiple MEMS device fabrication processes into a single integrated process on one substrate. Different MEMS devices (such as accelerometers, gyroscopes, and microphones) are formed simultaneously using shared processing steps including depositing sacrificial layers, forming structural layers, and performing release etching, thereby eliminating the need for separate bonding processes and reducing fabrication time and complexity
2Adaptability or versatility
If multiple bonding processes are used to assemble separate MEMS devices, then device functionality is achieved, but structural integrity is reduced due to potential damage from repeated bonding
Solution Approach 1:
The patent forms multiple MEMS devices in a single integrated fabrication process on one substrate, eliminating the need for multiple bonding steps. The devices share common structural layers and processing steps, resulting in a monolithic structure that maintains high structural integrity without the damage associated with repeated bonding operations
3Adaptability or versatility
If MEMS devices are fabricated separately, then each device can be independently designed, but the overall complexity of the manufacturing process increases
Solution Approach 1:
The patent integrates the fabrication of multiple different MEMS devices into a single unified manufacturing process. The process uses shared processing steps including depositing sacrificial layers (such as silicon dioxide or silicon nitride), forming structural layers, and performing release etching to simultaneously create accelerometers, gyroscopes, and other MEMS devices on one substrate, thereby reducing manufacturing complexity while maintaining design flexibility
Solution Approach 2:
The patent employs universal processing steps and materials that can be used to fabricate multiple types of MEMS devices. The same sacrificial layers, structural layers, and release processes are applied across different device types, allowing independent device design within a standardized, multi-functional fabrication framework that reduces overall process complexity
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 approach decreases fabrication time and cost while improving the structural integrity and performance of MEMS devices by integrating them on a single substrate, allowing for efficient and reliable operation.
Implementation Method 1
the first MEMS device comprises a diaphragm and a backplate spaced apart to form a capacitor
Implementation Method 2
the second MEMS device comprises a movable element and a backplate spaced apart to form a capacitor
Data Source
AI summary
Various embodiments of the present disclosure are directed towards an electronic device that comprises a semiconductor substrate having a first surface opposite a second surface. The semiconductor substrate at least partially defines a cavity. A first microelectromechanical systems (MEMS) device is disposed along the first surface of the semiconductor substrate. The first MEMS device comprises a first backplate and a diaphragm vertically separated from the first backplate. A second MEMS device is disposed along the first surface of the semiconductor substrate. The second MEMS device comprises spring structures and a moveable element. The spring structures are configured to suspend the moveable element in the cavity. A segment of the semiconductor substrate continuously laterally extends from under a sidewall of the first MEMS device to under a sidewall of the second MEMS device.