Rear-Side IC Substrate Tamper Detection by Resistive Monitoring

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Solution Overview

Problem

Integrated circuits, particularly those with sensitive memories, are vulnerable to fault injection attacks from the back side, which can compromise their integrity and data security, and existing protection methods are either complex or require significant surface area.

Innovation Solution

A detection system using contact points on the front face of the substrate to measure resistive values, comparing them to nominal values, and generating an alarm signal when deviations indicate tampering, such as removal or thinning of the substrate, to trigger countermeasures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the substrate is thinned from the rear face to enable fault injection attacks, then the effectiveness of attacks increases, but the security of the integrated circuit deteriorates

Engineering Contradiction:
Improveattack effectivenessVSAvoidcircuit security
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-installing a conductive plate within the coating layer before any attack can occur. This plate serves as a detection mechanism that is already in place, allowing the system to detect substrate thinning or coating openings as soon as an attacker begins their work, thereby preventing the attack from succeeding while maintaining the substrate's original thickness and security

Inventive Principle:
Principle #10Preliminary action

2Difficulty of detecting and measuring

If complex detection mechanisms are implemented to detect substrate attacks, then detection capability improves, but device complexity increases

Engineering Contradiction:
Improveattack detection capabilityVSAvoiddetection system complexity
Core Design Contradiction:
Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical or optical detection systems with an electrical measurement system. By using a conductive plate and measuring electrical resistance or conductivity changes, the system achieves high detection capability through simple electrical measurements rather than complex mechanical sensors or imaging systems

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

Solution Approach 2:

The conductive plate acts as an intermediary element between the substrate and the detection system. It converts physical changes in the substrate (thinning, openings) into measurable electrical signal changes, simplifying the detection process while maintaining high sensitivity to attack conditions

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If multiple contact points are used for resistive measurements, then measurement precision improves, but manufacturing complexity increases

Engineering Contradiction:
Improveresistive value measurement accuracyVSAvoidcontact points fabrication
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent segments the measurement system into multiple contact points distributed across the substrate surface. This segmentation allows precise localization of attacks and improves measurement accuracy by providing multiple data points, while the contact points can be fabricated using standard semiconductor processing techniques that are already integrated into the manufacturing flow

Inventive Principle:
Principle #1Segmentation

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

Effectively detects and responds to attacks by generating an alarm signal, allowing for timely protection of the integrated circuit without requiring a large surface area or complex implementation.

Implementation Method 1

said detection comprises a first measurement of a resistive value of the substrate between a set of n mutually electrically coupled and distributed contact points at the front face, and the electrically conductive plate

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentEP3525236B1Method of detecting violation of the integrity of a semi-conductor substrate of an integrated circuit from the rear surface thereof, and corresponding device
Publication Date: 2026.05.06 STMICROELECTRONICS (ROUSSET) SAS
  • EP3525236B1 patent drawingFigure 1~2
  • EP3525236B1 patent drawingFigure 3~4
  • EP3525236B1 patent drawingFigure 5~7

AI summary

Method for detecting damage to the integrity of a semiconductor substrate (P) of an integrated circuit (IC) protected by an encapsulation, the substrate comprising a front face (FV) and a rear face (FR), this damage being likely to be carried out from the rear face (FR) of the substrate, the method comprising detecting an opening in the encapsulation opposite the rear face of the substrate.