MEMS Acoustic Element Layout Without Metal Cap Alignment
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Solution Overview
Problem
Existing MEMS acoustic elements face challenges in miniaturization, require expensive metal caps, and have difficulties in alignment during mounting due to complex configurations and structural constraints.
Innovation Solution
A MEMS acoustic element design that includes a first substrate with a through hole, a second substrate overlapping the first, a vibration layer spanning the through hole, a resin layer covering the vibration layer, and pad electrodes on the resin layer, eliminating the need for a metal cap and simplifying alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a cap is designed considerably larger than the sensor chip to ensure positional accuracy during mounting, then the positional accuracy is improved, but the size of the entire sensor module increases
Solution Approach 1:
The patent removes the cap component entirely from the sensor module structure. Instead of using a cap to cover and protect the sensor chip, the invention uses a flat board-like structure with the sensor chip mounted directly on it, eliminating the need for a cap and thereby reducing the overall module size while maintaining mounting precision through direct chip mounting techniques
Solution Approach 2:
The invention separates the cap function from the board structure. The board serves as both the mounting substrate and the protective element, with the sensor chip directly mounted on the board surface. This segmentation allows the board to be sized precisely to the chip requirements rather than requiring an oversized cap for positioning
2Reliability
If a metal cap is used to ensure durability and protection, then the reliability is improved, but the manufacturing cost increases
Solution Approach 1:
The patent replaces expensive metal caps with a cost-effective board structure that provides sufficient protection for the sensor chip. The board serves as a durable mounting substrate that protects the chip from physical damage and environmental factors, achieving the necessary reliability at a lower manufacturing cost by eliminating metal cap production and assembly
Solution Approach 2:
The invention changes the material parameter from metal to a board material (such as printed circuit board or other rigid substrate). This material substitution maintains the protective function while significantly reducing manufacturing cost, as board materials are generally more cost-effective than metal caps for this application
3Ease of manufacture
If space is provided for wires connecting MEMS chip and electronic circuit chip, then the electrical connection is enabled, but the size of the silicon microphone increases
Solution Approach 1:
The patent replaces the mechanical wire connection system with direct electrical contact through pad electrodes on the board. The sensor chip electrodes are directly connected to corresponding pad electrodes on the board surface, eliminating the need for wire routing spaces and associated structural elements, thereby reducing the overall device size while maintaining electrical connectivity
4Strength
If the electrode is disposed on the bottom surface of the substrate and the sound collector opening is formed on the opposite surface, then the structural integrity is maintained, but the alignment with housing becomes difficult
Solution Approach 1:
The patent inverts the conventional arrangement by placing both the electrodes and the sound collector opening on the same surface of the substrate. This allows the sound collector opening to be directly aligned with the housing opening from the same side, eliminating the need for complex through-hole alignment and making the mounting process simpler while maintaining structural integrity through alternative electrode positioning
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
The proposed design enables miniaturization of MEMS acoustic elements, reduces manufacturing costs by avoiding expensive metal caps, and facilitates easier alignment during mounting, thereby improving overall efficiency and cost-effectiveness.
Implementation Method 1
The vibration layer includes a piezoelectric layer, a first electrode layer disposed to overlap with a surface of the piezoelectric layer distant from the first substrate, and a second electrode layer disposed to overlap with a surface of the piezoelectric layer close to the first substrate
Data Source
AI summary
A device may include a first substrate provided with a first through hole. A device may include a second substrate arranged adjacent to the first through hole and configured to partially overlap with the first substrate on a second side of the first substrate. A device may include a vibration layer arranged adjacent to and overlap with the first substrate on a first side of the first substrate opposite the second substrate and configured to stride across the first through hole. A device may include a resin layer disposed to overlap with a portion of the vibration layer overlapping with the first substrate. A device may include a first pad electrode. A device may include a second pad electrode. A device may include the first pad electrode and the second pad electrode being disposed on a surface of the resin layer opposite from the vibration layer.