MEMS Acoustic Sensor Etching via Segmented Sacrificial Layers
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Solution Overview
Problem
Conventional manufacturing methods for micro-electromechanical system acoustic sensors face challenges with poor etching accuracy and complexity, leading to insufficient or excessive etching, which affects the yield and reliability of the finished products due to difficulties in the flow of etching solutions through small vias.
Innovation Solution
A manufacturing method involving the use of sacrificial layers and recesses to facilitate easy flow of etching solutions, with the formation of second electrodes and an acoustic flow channel between first and second electrodes, allowing for precise etching and reducing the risk of electrode breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If small vias are used in the conventional manufacturing method, then the device size is reduced, but the etching solution cannot flow in and out properly, causing poor etching accuracy
Solution Approach 1:
The patent segments the etching process into two distinct stages: first etching through the first oxide layer via small vias, then etching through the second oxide layer through larger openings. This segmentation allows each etching step to use appropriately sized openings for its specific purpose, resolving the contradiction between small device size and adequate etching solution flow.
Solution Approach 2:
The patent performs preliminary etching of the first oxide layer through small vias before forming the larger openings for the second oxide layer etching. This preliminary action prepares the structure in advance, allowing the etching solution to access and remove the first oxide layer, and subsequently the second oxide layer, with controlled precision at each stage.
2Ease of manufacture
If the conventional manufacturing method is used, then the process can be completed, but the steps are complicated and yield is poor
Solution Approach 1:
The patent divides the manufacturing process into clearly defined sequential steps with distinct purposes: forming small vias for first oxide layer etching, then forming larger openings for second oxide layer etching. This segmentation simplifies the overall process by making each step's function explicit and controllable, reducing complexity and improving yield through better process management.
3Manufacturing precision
If excessive etching is performed, then the oxide layers can be removed, but the insulating layer and electrode are damaged, causing product failure
Solution Approach 1:
The patent performs preliminary etching of the first oxide layer through small vias before creating larger openings for the second oxide layer. This preliminary action allows precise removal of the first oxide layer with minimal risk to underlying structures, and subsequent etching of the second oxide layer through larger openings with better solution flow control, preventing excessive etching damage to the insulating layer and electrode.
Solution Approach 2:
The patent segments the oxide layer removal into two controlled stages, each with its own opening size and etching parameters. This segmentation enables precise control over the etching depth and rate at each stage, ensuring complete oxide layer removal while protecting the insulating layer and electrode from excessive etching damage.
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 simplifies the manufacturing process, improves etching accuracy, and prolongs the service life of the micro-electromechanical system acoustic sensors by ensuring easy flow and removal of etching solutions and adjustable sacrificial layer thickness, thereby enhancing the yield and performance of the finished products.
Implementation Method 1
an etching solution is poured into the plurality of vias H, so as to etch the first oxide layer 94 and the second oxide layer 95
Data Source
AI summary
A manufacturing method of a micro-electromechanical system acoustic sensor includes: forming an insulating layer and two first electrodes on a base plate, the two first electrodes being spaced apart from each other; arranging a first sacrificial layer on the insulating layer and the two first electrodes, and forming at least one first recess in the first sacrificial layer respectively above the two first electrodes; arranging a second sacrificial layer on the first sacrificial layer and the at least two first recesses, forming two second recesses spaced apart in the second sacrificial layer, and making the two second recesses respectively communicate with the corresponding at least one first recess to form two recess spaces; filling the two recess spaces respectively with a material to form two second electrodes; and removing all the first sacrificial layer and the second sacrificial layer.