IC Attack Detection via Stray Capacitance Trenches
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Solution Overview
Problem
Integrated circuit chips are vulnerable to attacks such as fault injection and local etching, which existing detection solutions fail to reliably prevent or detect, leading to potential exposure of critical data.
Innovation Solution
The integration of parallel wells of alternated conductivity types with trenches filled with conductive material and a circuit that detects modifications in stray capacitance, preventing fault injection and detecting local etching attempts by modifying the chip's substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If logic integrity tests are introduced into calculations to detect attacks, then detection capability is improved, but chip response times increase due to additional calculation steps
Solution Approach 1:
The patent replaces logic-based integrity tests with a physical sensing mechanism. A sensor detects physical parameters (temperature, voltage, current) that change during laser attacks, enabling attack detection without additional calculation steps. This substitutes computational detection with direct physical measurement, resolving the contradiction between detection reliability and response time.
2Reliability
If physical sensors sensitive to temperature or radiation are implemented to detect attacks, then detection capability is improved, but device complexity and silicon surface area increase
Solution Approach 1:
The patent makes existing chip components multi-functional by enabling them to serve both their primary function and attack detection. For example, existing temperature sensors or circuit elements are configured to detect both operational parameters and attack-induced anomalies. This eliminates the need for dedicated sensor structures, reducing device complexity while maintaining detection capability.
3Measurement precision
If the chip substrate is thinned to improve laser attack efficiency detection, then attack detection sensitivity is improved, but chip structural strength and protection are reduced
Solution Approach 1:
The patent implements protective measures before the chip undergoes thinning. Reinforcement structures or protective layers are integrated into the chip design prior to substrate thinning, ensuring that the weakened substrate maintains sufficient mechanical strength. This preliminary reinforcement allows the chip to be thinned for improved attack detection sensitivity while preventing structural failure.
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 solution effectively prevents fault injection and detects local etching attempts, enhancing security without increasing the silicon surface area and addressing the limitations of existing solutions.
Implementation Method 1
a circuit capable of detecting a modification of the stray capacitance formed between said conductive material and a region of the chip
Implementation Method 2
preventing fault injection and detecting local etching attempts by modifying the chip's substrate
Data Source
AI summary
An integrated circuit chip including a plurality of parallel wells of alternated conductivity types formed in the upper portion of a semiconductor substrate of a first conductivity type, and a device of protection against attacks including: between the wells, trenches with insulated walls filled with a conductive material, said trenches extending from the upper surface of the wells to the substrate; and a circuit capable of detecting a modification of the stray capacitance formed between said conductive material and a region of the chip.