Semiconductor Cavity Adsorption Layer Non-Overlap Design
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Solution Overview
Problem
In semiconductor devices with microelectromechanical systems (MEMS) and inductors, coupling effects between the inductor and other elements reduce the quality factor, affecting stability and yield, particularly due to the overlap of adsorption layers with conductive materials like titanium.
Innovation Solution
A semiconductor device design where an adsorption layer is strategically positioned on the top substrate to form a cavity with the MEMS device and inductor, ensuring the adsorption layer and inductor do not overlap vertically, thereby reducing coupling effects and enhancing the quality factor by using a trench and specific material configurations like titanium for the adsorption layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an adsorption layer is disposed on the top substrate facing the front-end device, then the vacuum-like environment is maintained, but the coupling effect between the inductor and adsorption layer reduces the quality factor
Solution Approach 1:
The patent applies dimensionality change by transitioning from a two-dimensional planar adsorption layer to a three-dimensional trench structure. The adsorption layer is positioned within a trench that extends vertically into the top substrate, creating a non-planar configuration. This spatial transformation allows the adsorption layer to maintain contact with the cavity volume for vacuum maintenance while reducing overlapping area with the inductor in the horizontal plane, thereby minimizing coupling effects and preserving quality factor.
Solution Approach 2:
The trench structure serves as an intermediary element between the adsorption layer and the inductor. By introducing this intermediate spatial feature, the patent enables the adsorption layer to perform its vacuum maintenance function while physically separating it from direct overlap with the inductor. The trench acts as a mediator that reconciles the conflicting requirements of vacuum environment maintenance and quality factor preservation.
2Reliability
If the adsorption layer and inductor overlap in vertical direction, then the adsorption layer can maintain vacuum environment, but coupling effects reduce device performance
Solution Approach 1:
The patent resolves the manufacturing precision issue by changing the geometric configuration from a flat, two-dimensional adsorption layer to a three-dimensional trench-based structure. This dimensional transformation allows precise control over the spatial relationship between the adsorption layer and inductor, enabling manufacturers to maintain the hermetic environment while avoiding performance degradation through careful trench depth and positioning control.
3Loss of energy
If a trench is formed in the top substrate to position the adsorption layer, then coupling effects are reduced, but device structure becomes more complex
Solution Approach 1:
The patent applies merging by combining multiple functions into the trench structure. The trench simultaneously serves as: (1) a spatial container for the adsorption layer, (2) a structural feature that reduces coupling effects, and (3) an integral part of the cavity formation process. By merging these functions into a single structural element, the patent reduces overall device complexity compared to having separate components for each function.
Solution Approach 2:
The trench structure exhibits multi-functionality, serving both as a mechanical feature for positioning the adsorption layer and as an electromagnetic isolation structure to reduce coupling effects. This universal design approach allows a single structural element to address multiple performance requirements, thereby reducing the need for additional separate components and simplifying the overall device architecture.
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 configuration improves the stability and yield of semiconductor devices by minimizing coupling effects between the inductor and adsorption layers, maintaining a vacuum-like environment, and ensuring the performance of the semiconductor device.
Implementation Method 1
an adsorption layer disposed on a portion of the top substrate facing the front-end device
Data Source
AI summary
A semiconductor device includes a bottom substrate, wherein a front-end device including a microelectromechanical systems (MEMS) device and an inductor is disposed on the bottom substrate, and a top substrate bonded to the bottom substrate so as form a cavity enclosing the front-end device. The semiconductor device further includes an adsorption layer disposed on a portion of the top substrate facing the front-end device, wherein the adsorption layer and the inductor do not overlap in a vertical direction.