Embedded Magnetic Core Inductor with Protective Ring in Package Substrate

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Solution Overview

Problem

Existing integrated device packages with external inductors are too large and thick for mobile and wearable computing devices, making them unsuitable for these applications due to space constraints.

Innovation Solution

An integrated device package is designed with a magnetic core inductor and protective ring embedded in the package substrate, where the inductor is positioned to partially surround the magnetic core, and some interconnects serve both as part of the inductor and protective ring, reducing eddy currents and increasing inductance and quality factor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an external inductor is mounted on the PCB, then the inductor can function properly, but the device form factor becomes too large and thick for mobile and wearable devices

Engineering Contradiction:
Improveinductor functionVSAvoiddevice form factor
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent merges the inductor with the package substrate by embedding the inductor structure directly into the substrate layers. The interconnects are configured to form both the inductor windings and protective rings, integrating multiple functions into a single structure that resides within the package substrate rather than being a separate external component.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The inductor is nested within the package substrate structure. The interconnects are routed through multiple layers of the substrate, with the inductor windings formed by interconnects that pass through dielectric layers and are surrounded by protective rings, creating a nested configuration where the inductor is contained within the substrate volume.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Volume of moving object

If the inductor is integrated into the package substrate, then the device form factor is reduced, but the inductance and quality factor may be affected

Engineering Contradiction:
Improvedevice form factorVSAvoidinductance and quality factor
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

A magnetic core is introduced as an intermediary element embedded within the package substrate at the center of the inductor structure. The magnetic core enhances the inductance of the embedded inductor, compensating for the potential reduction in inductance that would result from the compact integrated design. The magnetic core acts as a mediator that improves the electromagnetic properties of the inductor within the constrained substrate environment.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The protective rings are formed as part of the interconnect structure before the inductor windings are completed. The protective rings are created by routing interconnects around the magnetic core location in advance, establishing a protective structure that prevents eddy currents before the full inductor is assembled. This preliminary formation of protective rings ensures optimal inductance and quality factor are achieved.

Inventive Principle:
Principle #10Preliminary action

3Loss of energy

If protective rings are added around the magnetic core, then eddy currents are reduced, but the device complexity increases

Engineering Contradiction:
Improveeddy currentsVSAvoidstructure complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The same interconnects that form the inductor windings are also configured to form the protective rings around the magnetic core. By routing the interconnects to serve dual purposes—as both the inductor windings and the protective rings—the patent eliminates the need for separate protective ring structures, thereby reducing device complexity while still providing eddy current protection.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 design enhances the inductance and quality factor of the inductor while reducing its size, allowing for a more compact form factor suitable for mobile and wearable devices.

Implementation Method 1

a magnetic core in the dielectric layer, a first inductor that includes a plurality of first interconnects. The first inductor is positioned in the package substrate to at least partially surround the magnetic core

Methodology Applied
Scientific EffectMagnetic core: Ferromagnetism

Implementation Method 2

The first protective ring comprises at least one interconnect from the plurality of first interconnects of the first inductor

Methodology Applied
Scientific EffectEddy current reduction: Eddy Currents

Data Source

PatentEP3254309B1Integrated device package comprising a magnetic core inductor with protective ring embedded in a package substrate
Publication Date: 2021.01.13 QUALCOMM INC
  • EP3254309B1 patent drawingFigure 1
  • EP3254309B1 patent drawingFigure 2
  • EP3254309B1 patent drawingFigure 3

AI summary

An integrated device package includes a die and a package substrate. The package substrate includes at least one dielectric layer (e.g., core layer, prepeg layer), a magnetic core in the dielectric layer, a first plurality of interconnects configured to operate as a first protective ring, and a second plurality of interconnects configured to operate as a first inductor. The second plurality of interconnects is positioned in the package substrate to at least partially surround the magnetic core. At least one interconnect from the second plurality of interconnects is also part of the first plurality of interconnects. In some implementations, the first protective ring is a non-contiguous protective ring. In some implementations, the first inductor is a solenoid inductor. In some implementations, the magnetic core includes a carrier, a first magnetic layer, and a second magnetic layer.