Conductive Glue PUF for IC Substrate Authentication

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

It is difficult to verify the authenticity of the assembly of integrated circuits and their substrates in electronic devices, such as smart cards, making them susceptible to tampering.

Innovation Solution

The use of conductive glue with quasi-randomly distributed particles to create a physical unclonable function (PUF), where drive currents flow through the glue to a receiving electrode, allowing for unique identification of each assembly by measuring the proportion of currents, thereby verifying the authenticity of the IC-substrate assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cryptographic capabilities are embedded in secure elements, then security is improved, but the ability to verify authenticity of the IC-substrate assembly is worsened

Engineering Contradiction:
ImprovesecurityVSAvoidauthenticity verification
Core Design Contradiction:
ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies preliminary action by creating a physical unclonable function (PUF) based on the random distribution of conductive particles in the glue layer during the manufacturing process. This PUF serves as a pre-established authentication mechanism that is inherently tied to the specific IC-substrate assembly, enabling future authenticity verification without requiring additional cryptographic infrastructure.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary measurement mechanism that uses the glue layer with conductive particles as a mediator between the IC and substrate. By measuring electrical properties (such as resistance or conductance) through the glue layer, the system creates a unique signature that authenticates the specific assembly, thus bridging the gap between the secure element and the substrate for verification purposes.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If conventional authentication methods are used, then verification capability is improved, but cost and resource consumption are worsened

Engineering Contradiction:
Improveauthentication capabilityVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent applies self-service by utilizing the glue layer, which is already present and necessary for the mechanical assembly of the IC to the substrate, to also serve as the authentication medium. The random distribution of conductive particles in the glue creates a unique electrical signature that can be measured and used for authentication, eliminating the need for separate authentication components or additional manufacturing steps.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent demonstrates multi-functionality by making the glue layer serve dual purposes: (1) providing mechanical bonding between the IC and substrate, and (2) creating a physical unclonable function for authentication. This eliminates the need for separate authentication hardware or materials, reducing overall system complexity and manufacturing cost while maintaining strong authentication capabilities.

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 method provides a cost-effective and resource-efficient means to uniquely identify each assembly, enhancing security by utilizing the inherent variability in the manufacturing process to create a unique signature for authentication.

Implementation Method 1

the glue comprises conductive particles which electrically connect the receiving electrode, the counter electrode and at least a part of the set of driving electrodes, such that, if drive currents are provided to said set of driving electrodes, at least a part of the drive currents flows to the receiving electrode through the conductive particles and the counter electrode

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3193281B1Electronic device
Publication Date: 2019.11.13 NXP BV
  • EP3193281B1 patent drawingFigure 1~2
  • EP3193281B1 patent drawingFigure 3~4
  • EP3193281B1 patent drawingFigure 5~6

AI summary

According to a first aspect of the present disclosure, an electronic device is provided which comprises: a substrate; an integrated circuit; a layer of glue between the substrate and the integrated circuit; a set of driving electrodes coupled to the glue and to the integrated circuit; a receiving electrode coupled to the glue and to the integrated circuit; a counter electrode coupled to the glue and to the substrate; wherein the glue comprises conductive particles which electrically connect the receiving electrode, the counter electrode and at least a part of the set of driving electrodes, such that, if drive currents are provided to said set of driving electrodes, at least a part of the drive currents flows to the receiving electrode through the conductive particles and the counter electrode. According to a second aspect of the present disclosure, a corresponding method of manufacturing an electronic device is conceived.