Random Connection Track PUF Layout for Stable IC Authentication

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Solution Overview

Problem

Existing physical unclonable functions (PUFs) in integrated circuits are sensitive to environmental variations and aging, leading to reduced robustness and increased volatility, necessitating costly post-processing circuits for security.

Innovation Solution

A method involving the creation of a network of random connection tracks using phase-separated materials during manufacturing, forming a non-clonable physical function that is insensitive to environmental conditions without additional post-processing, by utilizing block copolymers like PS-PMMA to form a unique and unclonable PUF.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing PUF techniques operate at the limits of electronic constraints to achieve unique identification, then authentication capability is improved, but sensitivity to environmental variations increases leading to reduced robustness

Engineering Contradiction:
Improveauthentication capabilityVSAvoidsensitivity to environmental variations
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the fundamental operating parameters from electrical signal propagation (sensitive to temperature, voltage, aging) to optical interference patterns (robust to environmental conditions). By using visible light wavelengths and measuring optical path differences through etalon cavities, the system achieves environmental insensitivity while maintaining authentication capability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent substitutes electrical/electronic measurement mechanisms with optical measurement mechanisms. Instead of using electrical signals that propagate through conductors and are affected by resistance and timing variations, the system uses optical interference phenomena where light waves interact with physical cavity structures, providing immunity to electrical environmental variations.

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

2Reliability

If PUF circuits operate at electronic constraints limits to produce unique responses, then identification uniqueness is improved, but aging defects cause response changes over time

Engineering Contradiction:
Improveidentification uniquenessVSAvoidcircuit lifetime stability
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent transitions from electrical parameter-based identification (propagation time, resistance) to optical parameter-based identification (optical path length, interference patterns). Optical parameters in the etalon cavities remain stable over the circuit's lifetime, preventing the drift and defects that plague electrical PUF implementations during aging.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If post-processing circuits are added to compensate for environmental sensitivity, then robustness is improved, but device complexity and cost increase

Engineering Contradiction:
Improveenvironmental robustnessVSAvoidpost-processing circuit complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent converts the inherent technological dispersions and manufacturing variations, which traditionally harm electrical PUF performance, into beneficial random optical path differences. The uncontrolled variations in etalon cavity dimensions during manufacturing create unique interference patterns that are environmentally stable, eliminating the need for complex post-processing compensation circuits.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

4Reliability

If unique identifiers are stored in databases for authentication, then authentication capability is improved, but vulnerability to emulation attacks increases

Engineering Contradiction:
Improveauthentication capabilityVSAvoidvulnerability to emulation attacks
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent transforms manufacturing imperfections and technological dispersions into beneficial random optical path variations. These uncontrolled variations create unique, unclonable interference patterns for each circuit, providing physical unclonability that prevents emulation attacks while maintaining authentication capability.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes from storing electrical identifiers in databases (vulnerable to replay and emulation) to using optical interference patterns as physical unclonable functions. The optical parameters embedded in the physical structure of each circuit cannot be easily copied or emulated, providing superior security against attacks.

Inventive Principle:
Principle #35Parameter changes

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 ensures robust authentication against replay attacks and environmental variations, making cloning extremely difficult and maintaining circuit identity throughout its life cycle.

Implementation Method 1

creation in said security zone of a network of random connection tracks by a controlled introduction of a phase-separated material

Methodology Applied
Scientific EffectPhase separation: Phase Change

Data Source

PatentEP3418936B1Method for securing an integrated circuit during the production thereof using random connecting trakcs
Publication Date: 2025.09.03 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP3418936B1 patent drawingFigure 1~2
  • EP3418936B1 patent drawingFigure 3A~3D
  • EP3418936B1 patent drawingFigure 3E~3H

AI summary

The invention relates to a method for securing an integrated circuit when it is produced on a plate, said method comprising the following steps: -delimitation of said plate of the integrated circuit (1) in a first zone called the standard zone (5a) and in a second zone called the security zone (5b), and -creation in the said security zone (5b) of a network of random connection tracks (7b) configured to interconnect a set of conductive nodes (9b) thus forming a function non-cloneable physics modeled by a random electrical continuity that can be interrogated via said set of conductive nodes by a challenge-response authentication protocol.