MEMS Movable Mass Structuring via Sacrificial Stator Electrode
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Solution Overview
Problem
The manufacturing of micromechanical components, particularly in silicon-on-insulator (SOI) configurations, often requires complex and costly processes involving multiple etching steps and additional semiconductor layers, which can lead to mechanical stresses and increased production costs.
Innovation Solution
A manufacturing method that structures the movable mass and spring directly from the substrate without the need for additional semiconductor layers, allowing only front-side processes and eliminating the necessity for back-side etching, thereby reducing costs and mechanical stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If additional semiconductor layers are deposited on insulating/sacrificial layers to form the movable mass, then the movable mass can be structured, but mechanical stresses occur and manufacturing complexity increases
Solution Approach 1:
The patent extracts and eliminates the insulating/sacrificial layer from the conventional SOI structure, allowing the movable mass to be formed directly from the substrate without requiring additional semiconductor layers. This removes the source of mechanical stress and simplifies the manufacturing process while maintaining the ability to structure the movable mass precisely.
Solution Approach 2:
Instead of following the conventional approach of depositing semiconductor layers on insulating layers to form the movable mass, the patent inverts the process by forming the movable mass directly from the substrate and using the stator electrode as the sacrificial element. This reversal eliminates the need for complex layer deposition and reduces manufacturing steps.
2Manufacturing precision
If multiple etching and deposition steps are performed to form stator electrodes and movable mass, then proper electrode structure is achieved, but manufacturing costs increase
Solution Approach 1:
The patent merges the formation of the movable mass and stator electrode into a unified process where both structures are created from the substrate in sequence without requiring separate deposition of semiconductor layers. The stator electrode serves dual purposes as both a structural element and a sacrificial layer, reducing the total number of manufacturing steps and costs.
Solution Approach 2:
The stator electrode is designed as a disposable sacrificial element that is formed, used for structuring the movable mass, and then removed. This approach eliminates the need for expensive additional semiconductor layers and complex deposition processes, reducing manufacturing costs while achieving the required electrode structure.
3Manufacturing precision
If back-side etching processes are used to structure the movable mass, then proper release is achieved, but process complexity and time increase
Solution Approach 1:
The patent inverts the conventional approach by performing all structuring and release operations from the front side only. The movable mass is structured and released using front-side etching processes targeting the stator electrode as sacrificial material, eliminating the need for back-side etching and reducing manufacturing cycle time.
Solution Approach 2:
The patent segments the manufacturing process into distinct front-side operations: forming the stator electrode, structuring the movable mass using the stator electrode as mask, and releasing the movable mass by removing the stator electrode. This segmentation allows all critical steps to be completed from the front side without requiring back-side processing.
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 simplifies the manufacturing process, reduces costs, and maintains good mechanical and electrical properties of both silicon-based and metal-based MEMS sensors, enabling the production of high-capacity acceleration and magnetic field sensors with improved accuracy and reduced mechanical stress.
Implementation Method 1
a variable with regard to a capacitance of at least one capacitor formed from the at least one stator electrode and the at least one actuator electrode
Implementation Method 2
In another specific embodiment it is possible to mount/provide a coil on the movable mass. In this case the micromechanical component according to the present invention may be used as a sensitive element of a magnetic field sensor.
Data Source
AI summary
A micromechanical component is described having a substrate which has a movable mass which is connected via at least one spring to the substrate so that the movable mass is displaceable with respect to the substrate, and at least one fixedly mounted stator electrode. The movable mass and the at least one spring are structured from the substrate. At least one separating trench which at least partially surrounds the movable mass is formed in the substrate. The at least one stator electrode is situated adjacent to an outer surface of the movable mass which is at least partially surrounded by the separating trench, with the aid of at least one supporting connection which connects the at least one stator electrode to an anchor situated on the substrate and spans a section of the separating trench. Also described is a manufacturing method for a micromechanical component.