Conformal ALD Insulation for High-Voltage Magnetic Sensors

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Solution Overview

Problem

Existing insulation methods for sensitive electronic components in high-current and high-field environments, such as current sensors, suffer from adhesion issues and potential discharge risks, which compromise sensitivity and device integrity.

Innovation Solution

Implementing a conformal insulating layer using atomic layer deposition (ALD) between substrates, particularly with metal oxides like alumina, to ensure precise control of distance and effective insulation, reducing dielectric breakdown and partial discharge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If adhesive tape is used for insulation between circuits, then discharge is reduced, but adhesion issues arise and discharge may still occur around the tape

Engineering Contradiction:
Improveinsulation reliabilityVSAvoidadhesion quality
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces the mechanical adhesive tape system with a conformal insulating layer deposited by atomic layer deposition (ALD). This deposition process creates a continuous, adherent insulating film that eliminates the adhesion problems of tape while providing complete coverage without gaps where discharge could occur.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the insulating material from polyimide adhesive tape to metal oxide (such as alumina) deposited by ALD. This material substitution provides superior adhesion, higher breakdown voltage, and conformal coverage that eliminates the discharge paths present around tape edges.

Inventive Principle:
Principle #35Parameter changes

2Volume of moving object

If components are placed closer together to reduce device size, then device compactness is improved, but the risk of discharge and damage increases

Engineering Contradiction:
Improvedevice sizeVSAvoiddischarge risk
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent uses metal oxide materials (such as alumina) with significantly higher breakdown voltages compared to conventional polyimide tape. This material parameter change enables safe placement of components at closer distances while maintaining insulation reliability, thus reducing device size without increasing discharge risk.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The conformal ALD deposition process creates a uniform, gap-free insulating layer that provides reliable electrical isolation even at reduced component spacing. This replaces the inadequate mechanical tape system with a precise thin-film deposition approach that maintains insulation integrity at smaller dimensions.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If polyimide adhesive tape is used for isolation, then insulation is provided, but the presence of the tape affects the sensitivity of the device

Engineering Contradiction:
Improveinsulation protectionVSAvoidsensor sensitivity
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent replaces polyimide tape with metal oxide materials that have superior electrical properties including higher breakdown voltage and lower dielectric loss. These material parameter changes improve insulation performance while minimizing interference with the electromagnetic field, thereby preserving sensor sensitivity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The conformal thin-film deposition creates a uniform insulating layer that is more electrically homogeneous than adhesive tape. This eliminates the non-uniform field distribution caused by tape edges and adhesive interfaces, reducing measurement errors and improving sensor sensitivity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Ease of manufacture

If conventional deposition methods are used for insulating layers, then insulation is provided, but trenches and gaps may be clogged and uncoated areas remain

Engineering Contradiction:
Improvedeposition processVSAvoidcoating uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent employs atomic layer deposition (ALD) which uses a self-limiting surface reaction mechanism to deposit conformal insulating layers. This deposition method automatically ensures uniform coating on complex three-dimensional structures including trenches and gaps, eliminating the clogging and uncoated areas problems associated with conventional deposition techniques.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The ALD process is self-limiting, meaning each deposition cycle automatically terminates when the surface is fully covered. This self-regulating mechanism ensures complete and uniform coating of all surfaces including deep trenches and high aspect ratio gaps without requiring external control or risking over-deposition that could cause clogging.

Inventive Principle:
Principle #25Self-service

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

The method enhances sensitivity by allowing components to be placed closer together without risking breakdown, providing robust insulation with high breakdown voltages and reduced thermal stresses, thus improving the reliability and compactness of electronic devices.

Implementation Method 1

providing, by atomic layer deposition, an insulating layer between the first substrate and the second substrate

Methodology Applied
Scientific EffectAtomic layer deposition: Physical Vapour Deposition

Implementation Method 2

ALD is based on a self-limiting reaction, allowing filling of trenches and/or gaps gradually without clogging them

Methodology Applied
Scientific EffectSelf-limiting reaction:

Implementation Method 3

providing an insulating layer between the first substrate and the second substrate... keeping good insulation

Methodology Applied
Scientific EffectDielectric insulation: Dielectric

Implementation Method 4

a sensing element for sensing magnetic field caused by current through a second substrate

Methodology Applied
Scientific EffectMagnetic field sensing: Magnetic Field

Data Source

PatentEP4187261B1Conformal deposition for high voltage isolation
Publication Date: 2025.08.13 MELEXIS TECHNOLOGIES SA
  • EP4187261B1 patent drawingFigure 1~3
  • EP4187261B1 patent drawingFigure 4
  • EP4187261B1 patent drawingFigure 5~6

AI summary

A method of manufacture of a sensor and a sensor for sensing a magnetic field generated by a current in a conductive substrate are provided. A first substrate comprising a sensing element for sensing magnetic field, and a second substrate is the conductive substrate. A conformal layer is provided by atomic layer deposition between the first substrate and the second substrate, thus protecting at least the sensing element from discharge from the second substrate.