Thermal Neutron Absorber Layer for Soft Error Mitigation

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Solution Overview

Problem

Integrated circuits are prone to soft errors due to thermal neutrons, which are not effectively addressed by conventional packaging methods that avoid alpha particle emitters, as these methods do not account for neutron-induced errors.

Innovation Solution

Incorporating thermal neutron absorbers, such as boron-10, gadolinium-157, or cadmium-113, into packaging layers at least 50 µm from the integrated circuit surface to absorb thermal neutrons and reduce radiation-related soft errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional packaging methods are used that avoid alpha particle emitters, then alpha particle radiation damage is reduced, but thermal neutron-induced soft errors are not addressed

Engineering Contradiction:
Improvealpha particle radiation damageVSAvoidresistance to thermal neutron-induced soft errors
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The packaging structure is segmented into multiple functional layers: an alpha particle emitter-free molding compound layer and a separate thermal neutron absorber layer. This segmentation allows each layer to specifically address one type of radiation hazard without interfering with the other, resolving the contradiction between protecting against alpha particles while also protecting against thermal neutrons

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A thermal neutron absorber layer is introduced as an intermediary component between the integrated circuit and the external environment. This intermediary layer specifically absorbs thermal neutrons before they can reach the circuit, while not interfering with the alpha particle protection provided by the molding compound, thus resolving the contradiction

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If thermal neutron absorbers are incorporated into packaging layers, then soft errors from thermal neutrons are reduced, but the packaging structure becomes more complex

Engineering Contradiction:
Improveresistance to thermal neutron-induced soft errorsVSAvoidpackaging structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The thermal neutron absorber is merged with the existing molding compound structure by incorporating it as a distinct layer within the same packaging assembly. This merging approach integrates the new functionality into the existing structure rather than adding completely separate protective systems, thereby reducing the perceived complexity while maintaining reliability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The packaging structure is designed with multi-functionality by incorporating layers that address multiple radiation types (alpha particles and thermal neutrons) within a single integrated packaging system. This universal approach protects against both radiation types simultaneously, reducing the need for separate protective measures and simplifying the overall system

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

The use of thermal neutron absorbers in packaging layers significantly reduces soft errors by effectively absorbing thermal neutrons, enhancing the reliability and data integrity of integrated circuits.

Implementation Method 1

a thermal neutron absorber layer disposed over the film layer. The thermal neutron absorber layer includes at least 0.5% by weight of a thermal neutron absorber

Methodology Applied
Scientific EffectNeutron absorption: Absorption (EM radiation)

Data Source

PatentEP3780090A1Soft error resistant circuitry
Publication Date: 2021.02.17 INFINEON TECHNOLOGIES LLC
  • EP3780090A1 patent drawingFigure 1~2
  • EP3780090A1 patent drawingFigure 3
  • EP3780090A1 patent drawing

AI summary

An assembly includes an integrated circuit, a film layer disposed over the integrated circuit and having a thickness of at least 50 microns, and a thermal neutron absorber layer comprising at least 0,5% thermal neutron absorber. The thermal neutron absorber layer can be a glass layer or can include a molding compound.