Semiconductor Device With Local Electromagnetic Shielding
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Solution Overview
Problem
Conventional RF switches suffer from signal distortions due to electron capture and emission at the interface between the substrate and the buried oxide layer, leading to radio frequency and intermodulation distortions, which cannot be sufficiently suppressed by existing trap rich layers, and the use of quartz substrates is costly.
Innovation Solution
A semiconductor device with a circuit substrate featuring an insulating film layer, a semiconductor layer, and a locally provided electromagnetic shield layer in the insulating film layer, electrically separated from the semiconductor substrate, which cuts noise generated by inversion electrons at the interface, thereby reducing signal distortions without increasing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If quartz substrate is used to suppress distortion generation, then distortion suppression is improved, but manufacturing cost increases
Solution Approach 1:
The invention changes the structural parameters of the device by introducing additional functional layers (electromagnetic shield layer and trap rich layer) rather than changing the fundamental substrate material from silicon to quartz. This parameter change approach maintains compatibility with conventional silicon substrate manufacturing processes while achieving distortion suppression performance comparable to or better than quartz substrates, thereby avoiding the significant cost increase associated with quartz substrate adoption.
Solution Approach 2:
The electromagnetic shield layer is formed using conventional conductive materials and deposition techniques that are already part of standard CMOS fabrication processes. This approach uses readily available, cost-effective materials and processes rather than requiring expensive quartz substrates, making the solution economically viable for mass production while achieving the desired distortion suppression performance.
2Reliability
If electromagnetic shield layer is provided to cut noise from inversion electrons, then signal distortion is suppressed, but device structure becomes more complex
Solution Approach 1:
The electromagnetic shield layer is segmented into multiple regions corresponding to different passive elements (capacitors and inductors) in the LC tank circuit. Each shield layer portion is positioned directly beneath or adjacent to the specific passive element it needs to protect, rather than providing a continuous shield across the entire device. This segmented approach reduces the total amount of conductive material required and simplifies the fabrication process while maintaining effective noise suppression at each critical location.
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 semiconductor device effectively suppresses signal distortions and maintains low manufacturing costs by using an electromagnetic shield layer to shield noise caused by inversion electrons, enhancing the reliability of RF switches.
Implementation Method 1
an electromagnetic shield layer locally provided in the insulating film layer corresponding to a portion where at least one of the plurality of passive elements is provided, the electromagnetic shield layer and the semiconductor substrate being electrically separated from each other
Data Source
AI summary
To more reliably suppress deterioration in characteristics due to signals (distortions) other than input and output waves while suppressing manufacturing cost. A semiconductor device according to the present disclosure includes a circuit substrate including an insulating film layer located above a predetermined semiconductor substrate and a semiconductor layer located above the insulating film layer, a plurality of passive elements provided on the circuit substrate and electrically connected with one another, and an electromagnetic shield layer locally provided in the insulating film layer corresponding to a portion where at least one of the plurality of passive elements is provided, and the electromagnetic shield layer and the semiconductor substrate are electrically separated from each other.