Stacked RF Filter Structure Without Large Inductors
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Solution Overview
Problem
Conventional RF signal filters require large inductors, which restrict layout design and increase area occupancy, posing challenges in miniaturization and cost-effectiveness in integrated circuits.
Innovation Solution
A radiofrequency filter design incorporating a dielectric layer between conductive structures with contact structures forming low and high impedance paths, eliminating the need for large inductors, and integrating with transistor manufacturing processes to reduce area and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional RF signal filter uses a large inductor to achieve signal filtering, then the filtering effect is improved, but the area occupied by the inductor increases, restricting layout design
Solution Approach 1:
The patent transitions from planar inductor structures to a three-dimensional capacitor-based filter design using stacked conductive plates separated by dielectric layers. This vertical stacking approach utilizes the third dimension (height) to achieve the filtering function, thereby reducing the horizontal footprint on the substrate while maintaining effective signal filtering capability
Solution Approach 2:
The patent changes the fundamental filtering mechanism from inductance-based to capacitance-based operation. By adjusting capacitance values through varying plate area, plate spacing, and dielectric material properties, the filter achieves the desired frequency selection without requiring large inductors, thus resolving the area occupancy issue while preserving filtering effectiveness
2Reliability
If large inductors are used in RF filters, then signal filtering is achieved, but the layout design flexibility is reduced and manufacturing cost increases
Solution Approach 1:
By stacking conductive plates vertically with dielectric layers in between, the filter structure utilizes the vertical dimension to achieve capacitance values that would otherwise require large planar areas. This dimensional transition provides greater layout flexibility as the horizontal footprint is significantly reduced, allowing more freedom in circuit arrangement and integration
Solution Approach 2:
The patent employs composite structures combining conductive plates (metal layers) with dielectric materials (insulating layers) to form capacitor units. This composite approach enables precise control of capacitance values through material selection and geometric parameters, simplifying the design process and reducing manufacturing complexity compared to traditional inductor-based filters
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 filter achieves effective signal filtering with reduced area occupancy, enhancing design flexibility and lowering manufacturing costs by utilizing dielectric and conductive layers to create impedance paths without large inductors.
Implementation Method 1
a dielectric layer is disposed between an electrically conductive structure and a patterned electrically conductive film
Data Source
AI summary
A radiofrequency filter includes a substrate, an isolation structure, an electrically conductive structure, a spacer structure, a dielectric layer, a patterned electrically conductive film, a first contact structure, and a second contact structure. The isolation structure is disposed in the substrate. The electrically conductive structure is disposed on the isolation structure. The spacer structure is disposed on the substrate and located on a sidewall of the electrically conductive structure. The dielectric layer is disposed on the electrically conductive structure. The patterned electrically conductive film is disposed on the dielectric layer. At least a part of the dielectric layer is located between the electrically conductive structure and the patterned electrically conductive film in a vertical direction. The first contact structure and the second contact structure are disposed on and electrically connected with the patterned electrically conductive film.