RF Filter Capacitor Structure for Inductor-Free Signal Filtering
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Solution Overview
Problem
Conventional RF signal filters require large inductors, which occupy significant area and restrict layout design in micro-processor systems, limiting design flexibility and increasing manufacturing costs.
Innovation Solution
A radiofrequency filter design that incorporates a dielectric layer between an electrically conductive structure and a patterned electrically conductive film, with first and second contact structures forming low and high electrical resistance paths to achieve signal filtering without the need for large inductors.
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 occupied area increases and layout design flexibility is reduced
Solution Approach 1:
The patent transitions from a planar inductor design to a three-dimensional capacitor structure by stacking conductive layers with dielectric material between them. This vertical stacking approach (adding the Z-dimension) allows the filter to achieve the required electrical characteristics without expanding the horizontal footprint, thereby reducing the occupied area while maintaining filtering performance
Solution Approach 2:
The patent changes the fundamental electrical parameter from inductance to capacitance. By using a capacitor structure with adjustable capacitance values (achieved through varying conductive layer areas and dielectric thicknesses), the filter achieves the desired frequency selective behavior without requiring large inductors, thus resolving the area constraint while maintaining filtering effectiveness
2Reliability
If a conventional RF signal filter uses a large inductor, then signal filtering is achieved, but layout design flexibility is restricted
Solution Approach 1:
By stacking conductive layers vertically with dielectric material between them, the patent creates a three-dimensional capacitor structure that achieves the required electrical characteristics in the vertical dimension rather than expanding horizontally. This enables greater layout flexibility as the filter can be integrated into compact circuit designs without constraining the horizontal placement of other components
Solution Approach 2:
The capacitor structure serves multiple functions: it provides the frequency-selective filtering action, enables adjustable capacitance values for different frequency bands, and integrates seamlessly with standard semiconductor manufacturing processes. This multi-functionality enhances layout flexibility as the same structural approach can be adapted to various RF filter applications without requiring specialized large-area inductor designs
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
Reduces the occupied area, enhances design flexibility, and lowers manufacturing costs by eliminating the need for large inductors while maintaining effective signal filtering capabilities.
Implementation Method 1
A radiofrequency filter and a manufacturing method thereof are provided in the present invention. A dielectric layer is disposed between an electrically conductive structure and a patterned electrically conductive film
Implementation Method 2
a first contact structure and a second contact structure are disposed on the patterned electrically conductive film for forming a low electrical resistance (or low electrical impedance) path and a high electrical resistance (or high electrical impedance) path so as to realize signal filtering
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.