Composite Passivation Layer for Harsh Environments

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Solution Overview

Problem

Existing passivation layers for integrated circuits, such as silicon mononitride and silicon carbide, are not robust enough to protect against all environmental conditions and require high deposition temperatures, which can be incompatible with certain devices, influencing their operation and limiting their application in harsh environments.

Innovation Solution

A thin and robust passivation layer is formed using atomic layer deposition with a matrix of insulating material and noble metal nanoparticles, allowing for low-temperature deposition (less than 300°C) and providing excellent protection against disruptive environments, suitable for a wide range of integrated circuits and sensors, including MEMS devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thick films of silicon mononitride or silicon carbide are used as passivation layers, then barrier protection against environmental conditions is improved, but deposition temperatures greater than 500°C are required which are incompatible with certain devices

Engineering Contradiction:
Improvebarrier protectionVSAvoiddeposition temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent uses a composite passivation layer structure combining silicon oxide and silicon nitride deposited by ALD. This composite structure achieves superior barrier properties and environmental protection while being compatible with low-temperature deposition processes (below 500°C), resolving the contradiction between protection quality and deposition temperature requirements.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the deposition temperature parameter from traditional high temperatures (>500°C) to low temperatures (below 500°C) by using atomic layer deposition technology. This parameter change enables the formation of high-quality passivation layers that are compatible with temperature-sensitive devices while maintaining excellent barrier properties.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If traditional passivation layers are used, then electrical stability is provided, but they are not robust enough to protect against all environmental conditions including harsh environments

Engineering Contradiction:
Improveenvironmental protectionVSAvoidenvironmental conditions
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent employs a composite passivation structure with silicon oxide and silicon nitride layers. This composite material approach provides enhanced protection against diverse environmental conditions including moisture, chemicals, and harsh environments, overcoming the limitations of single-material passivation layers.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent adds a dimensional aspect by creating a multi-layered passivation structure rather than relying on a single thick layer. This layered approach provides comprehensive environmental protection by addressing different protection requirements at different layers, enhancing robustness against various harmful environmental factors.

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

3Manufacturing precision

If high deposition temperatures are used to achieve high quality passivation films, then film quality is improved, but compatibility with temperature-sensitive devices and circuits is reduced

Engineering Contradiction:
Improvefilm qualityVSAvoiddevice compatibility
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The patent fundamentally changes the deposition temperature parameter from high (>500°C) to low (below 500°C) by adopting atomic layer deposition technology. This enables the formation of high-quality films with excellent conformality and control while maintaining compatibility with temperature-sensitive devices and circuits.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces traditional thermal deposition mechanisms with atomic layer deposition, a more precise chemical vapor deposition method. This substitution allows for superior film quality control at lower temperatures, enhancing device compatibility while maintaining manufacturing precision.

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

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 solution provides a high-quality, conformal passivation layer that prevents electrical short circuits and protects devices from harsh environments, enabling the use of integrated circuits and sensors in challenging conditions while being compatible with various materials and devices, including bio-compatible and optical elements.

Implementation Method 1

forming a first insulating layer on an upper surface of the sensor layer using atomic layer deposition (ALD)... forming a second insulating layer on portions of the upper surface of the first insulating layer and on the first plurality of noble metal nanoparticles by ALD

Methodology Applied
Scientific EffectAtomic layer deposition: Chemical Vapour Deposition

Data Source

PatentEP2973662B1Passivation layer for harsh environments and methods of fabrication thereof
Publication Date: 2021.06.02 ROBERT BOSCH GMBH
  • EP2973662B1 patent drawingFigure 1~2
  • EP2973662B1 patent drawingFigure 3~4
  • EP2973662B1 patent drawingFigure 5~8

AI summary

A method of fabricating a passivation layer and a passivation layer for an electronic device. The passivation layer includes at least one passivation film layer and at least one nanoparticle layer. A first film layer is formed of an insulating matrix, such as aluminum oxide (Al2O3) and a first layer of a noble metal nanoparticle layer, such as a platinum nanoparticle layer, is deposited on the first film layer. Additional layers are formed of alternating film layers and nanoparticle layers. The resulting passivation layer provides a thin and robust passivation layer of high film quality to protect electronic devices, components, and systems from the disruptive environmental conditions.