Vertically Stacked Inductors With Ferromagnetic Core
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Solution Overview
Problem
Existing inductors and transformers face challenges in achieving high inductance density, high turns ratio, and current handling capability, particularly in planar designs which are costly and have limited coupling, while also being incompatible with advanced semiconductor processes.
Innovation Solution
The implementation of vertically stacked inductor and transformer structures using a redistribution layer (RDL) and back end of line (BEOL) wiring layers, with a ferromagnetic material in between, allowing for high inductance density and efficient energy transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If planar transformer designs are used to achieve high turns ratio, then voltage transformation is possible, but the area footprint increases and coupling is limited
Solution Approach 1:
The patent transitions from planar (2D) transformer designs to vertically stacked (3D) configurations. The primary and secondary windings are arranged in different vertical layers separated by a magnetic core, enabling high turns ratio transformation within a compact footprint by utilizing the vertical dimension for magnetic coupling.
2Ease of manufacture
If planar inductor designs are used, then manufacturing is simpler, but inductance density is limited
Solution Approach 1:
The inductor structure employs vertically stacked windings in multiple layers with magnetic core integration, transforming the design from 2D planar to 3D stacked architecture. This enables high inductance density while maintaining compatibility with standard semiconductor manufacturing processes through layer-by-layer fabrication.
Solution Approach 2:
The patent integrates ferromagnetic materials (such as nickel-iron alloy or cobalt-iron-boron) with conductor layers to form composite inductor structures. The magnetic core material enhances the inductance density by concentrating magnetic flux, while the conductor layers provide electrical pathways, creating a functional composite structure.
3Power
If existing high turns ratio transformers are used, then voltage transformation is achieved, but current handling capability is reduced
Solution Approach 1:
The vertically stacked transformer design distributes windings across multiple vertical layers, allowing current to flow through parallel pathways in different layers. This 3D arrangement increases the effective cross-sectional area for current flow, enhancing current handling capability while maintaining high turns ratio voltage transformation through magnetic coupling between layers.
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 results in high inductance density, improved coupling, and enhanced current handling capabilities, reducing manufacturing costs and enabling better performance in on-chip power amplifiers with lower insertion loss.
Implementation Method 1
a varying current in the transformer's primary winding creates a varying magnetic flux in the transformer core and a varying magnetic field impinging on the transformer's secondary winding. This varying magnetic field at the secondary winding induces a varying electromotive force (EMF) or voltage in the secondary winding due to electromagnetic induction.
Implementation Method 2
a ferro magnetic material between the first conductor and the second conductor
Data Source
AI summary
The present disclosure relates generally to semiconductor structures, and more particularly, to structures and methods for implementing high performance vertically stacked inductors and transformers. The structure includes: a first conductor composed of a redistribution line; a second conductor composed of a back end of line wiring layer, coupled to the redistribution line; and a ferro magnetic material between the first conductor and the second conductor.