3D Magnetic Core Inductors for Compact High-Density Integration

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Solution Overview

Problem

Existing solutions for high-value inductors in integrated circuits face challenges such as large footprint, high cost, and limited inductor density due to their two-dimensional structure, which leads to increased surface area requirements and power loss issues.

Innovation Solution

The development of three-dimensional magnetic core devices with helical coils and laminated magnetic structures that minimize surface footprint, enhance inductor density, and improve Q-factor values by using conductive traces and magnetic shells with insulator layers, allowing for high-energy density inductors with reduced energy loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If two-dimensional metal patterns or surface mount inductors are used, then inductors can be integrated into circuits, but the footprint and surface area increase

Engineering Contradiction:
Improveinductor integrationVSAvoidsurface footprint
Core Design Contradiction:
Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent transitions from two-dimensional planar inductor structures to three-dimensional vertical structures by stacking multiple metal layers and using via connections to form helical or spiral coil patterns in the vertical dimension. This allows the inductor to achieve higher inductance values and better performance while occupying less surface area on the PCB or substrate.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If non-magnetic medium surrounds the conductor turns, then on-die or on-substrate inductors can be realized, but the inductance value becomes limited and cost increases

Engineering Contradiction:
Improveon-die inductor fabricationVSAvoidinductance value
Core Design Contradiction:
Ease of manufactureVSQuantity of substance

Solution Approach 1:

The patent employs composite material structures combining magnetic core materials with conductor windings in a three-dimensional configuration. The magnetic core material is strategically placed within and around the coil structure to concentrate magnetic flux, thereby achieving high inductance values in a compact footprint suitable for on-die or on-substrate integration without requiring large surface areas.

Inventive Principle:
Principle #40Composite materials

3Quantity of substance

If magnetic core inductors are placed side-by-side on PCB or substrate, then high value inductors can be realized, but the packaging substrate size increases

Engineering Contradiction:
Improveinductance valueVSAvoidpackaging substrate area
Core Design Contradiction:
Quantity of substanceVSArea of stationary object

Solution Approach 1:

The patent utilizes vertical stacking of multiple conductor layers separated by insulating layers, with via connections forming three-dimensional coil patterns. This vertical configuration allows high-value inductors to be realized within a compact footprint on the packaging substrate, eliminating the need for large side-by-side placements while maintaining high inductance values through optimized magnetic flux paths.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Adaptability or versatility

If air core inductors are used on TSI RDL metals, then integration is achieved, but Q-factor decreases and cost increases

Engineering Contradiction:
ImproveTSI integrationVSAvoidQ-factor
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces magnetic core materials into the inductor structure to replace air cores, thereby concentrating magnetic flux and improving the Q-factor. The composite structure combines magnetic materials with conductor traces on the TSI substrate, achieving both high Q-factor performance and compatibility with existing TSI manufacturing processes while reducing the need for costly deep via etching and filling operations.

Inventive Principle:
Principle #40Composite materials

5Adaptability or versatility

If planar spiral inductors are used, then integration is achieved, but manufacturing cost increases

Engineering Contradiction:
Improveinductor integrationVSAvoidmanufacturing cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent employs three-dimensional vertical coil structures formed by stacking multiple metal layers with via connections, replacing costly planar spiral inductor fabrication. This vertical configuration allows inductors to be integrated using standard multi-layer PCB or substrate manufacturing processes, significantly reducing manufacturing costs while maintaining design flexibility and integration capabilities.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 approach enables the creation of compact, high-density inductors with improved Q-factor values, reducing energy loss and cost while maintaining high current handling capabilities, suitable for applications like voltage regulator circuits and RF circuits.

Implementation Method 1

the value of the inductance is directly proportional to the amount of the magnetic field coupled to the turns of the conductor

Methodology Applied
Scientific EffectMagnetic flux coupling: Magnetic Field

Implementation Method 2

Magnetic core material is used in surface mount discrete inductors

Methodology Applied
Scientific EffectFerromagnetism: Ferromagnetism

Implementation Method 3

laminated magnetic structures that minimize surface footprint, enhance inductor density, and improve Q-factor values

Methodology Applied
Scientific EffectEddy current reduction through lamination: Eddy Currents

Implementation Method 4

An inductor usually contains one or more turns of a conductor, around an air core or magnetic core, and the value of the inductance is directly proportional to the amount of the magnetic field coupled to the turns of the conductor due to an alternating current flowing through that conductor

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2940700B1Magnetic-core three-dimensional (3D) inductors and packaging integration
Publication Date: 2020.06.10 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD
  • EP2940700B1 patent drawingFigure 1A~1B
  • EP2940700B1 patent drawingFigure 1C~1D
  • EP2940700B1 patent drawingFigure 2A~2C

AI summary

A 3-dimensinal (3-D) magnetic core device includes a substrate, a first magnetic shell formed on the substrate, and a first group of conductive traces embedded in a first insulator layer formed on the first magnetic shell. A magnetic core plane is formed on the first insulator layer, and a second group of conductive traces are embedded in a second insulator layer formed on the magnetic core plane. A second magnetic shell is formed on the second insulator layer, and the first and second group of conductive traces are conductively coupled by using conductive vias.