Multilayer Isolation for Magnetic Inductor Stacks

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Solution Overview

Problem

On-chip magnetic inductor stacks face issues with magnetic losses due to pinhole formation in low-temperature deposited dielectric materials, leading to unwanted electrical connections and eddy currents.

Innovation Solution

A multilayer isolation scheme is employed using alternating layers of different dielectric materials or different deposition processes for the dielectric layers between magnetic layers, which are discontinuous and prevent eddy current losses while maintaining a low temperature and high throughput process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If low temperature dielectric deposition is used to preserve magnetic material properties, then magnetic properties are maintained, but pinhole formation occurs causing electrical connections between magnetic layers

Engineering Contradiction:

Improvedeposition temperatureVSAvoidelectrical isolation

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The single dielectric layer is segmented into multiple thin dielectric layers deposited at different times. This segmentation ensures that even if pinholes form in individual layers, they will not align to create continuous electrical pathways between magnetic layers, thus maintaining electrical isolation while using low temperature deposition processes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The solution transitions from a single-dimensional (one-layer) dielectric structure to a multi-dimensional (multiple-layer) structure. By adding the layer dimension, the patent creates a more robust electrical isolation barrier that accounts for pinhole formation in any single layer, effectively solving the reliability issue without increasing deposition temperature.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Loss of energy

If thicker dielectric layers are used to prevent eddy currents, then magnetic losses are reduced, but film thickness increases and aspect ratio worsens

Engineering Contradiction:

Improvemagnetic lossesVSAvoidfilm thickness

Core Design Contradiction:

Loss of energyVSLength of moving object

Solution Approach 1:

Instead of using one thick dielectric layer, the patent segments the isolation function across multiple thin layers. This achieves the same or better eddy current prevention (by ensuring complete electrical isolation) while keeping each individual layer thin, thus reducing overall film thickness and improving aspect ratio for downstream processing.

Inventive Principle:

Principle #1Segmentation

3Device complexity

If single layer dielectric material is used for isolation, then process complexity is reduced, but pinhole formation causes electrical connections

Engineering Contradiction:

Improvedielectric layer structureVSAvoidelectrical isolation

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The dielectric isolation function is segmented into multiple layers, which increases structural complexity but dramatically improves reliability by preventing pinhole-induced electrical connections. The segmentation transforms a single point of failure into multiple independent barriers.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs composite dielectric structures with multiple layers that may have different material compositions or deposition characteristics. This composite approach enhances electrical isolation reliability by ensuring that pinholes in one layer do not compromise overall isolation, while still maintaining compatibility with low temperature processing.

Inventive Principle:

Principle #40Composite materials

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 reduces magnetic losses by ensuring electrical isolation between magnetic layers, allowing for thinner film thickness and lower aspect ratios, facilitating easier downstream processing and improved performance in on-chip power converters and RF circuits.

Implementation Method 1

a multilayered insulating material enclosing the metal lines, wherein the multilayered insulating material is intermediate adjacent magnetic material layers

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Implementation Method 2

The dielectric material used in the magnetic inductor stacks is generally deposited at low temperatures in order not to destroy the magnetic properties of the magnetic material

Methodology Applied

Scientific EffectLow temperature deposition: Deposition (physical)

Data Source

PatentUS10177213B2Magnetic inductor stacks with multilayer isolation layers

Publication Date: 2019.01.08 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

A magnetic laminating structure and process includes alternating layers of a magnetic material and a multilayered insulating material, wherein the multilayered insulating material is intermediate adjacent magnetic material layers and comprises a first insulating layer abutting at least one additional insulating layer, wherein the first insulating layer and the at least one additional insulating layer comprise different dielectric materials and/or are formed by a different deposition process, and wherein the layers of the magnetic material have a cumulative thickness greater than 1 micron.