Floating Gate Transistor Attack Detection in Integrated Circuits
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Solution Overview
Problem
Integrated circuits, particularly those with sensitive information, face challenges in detecting and responding to attacks by beams of electrically charged particles during reverse engineering, as existing solutions are unreliable and incompatible with advanced technologies, leading to issues like current leaks and false-positive results.
Innovation Solution
Incorporating at least one electrically conductive body and a state transistor with a floating gate, configured to have an initial threshold voltage, which detects changes in threshold voltage due to charge collection during an attack, allowing for reliable detection and tracking of attacks using non-volatile memory with floating gate transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If invisible polarizing elements are used to create current variations for detection, then detection capability is provided, but current leakage and temperature-related instabilities occur leading to false-positive results
Solution Approach 1:
The patent extracts the detection function from the polarizing element approach and implements it directly through floating gate transistors that naturally store charge. The harmful polarizing elements are removed entirely, replaced by a simpler transistor-based detection mechanism that reads threshold voltage changes without generating current leakage or false positives.
Solution Approach 2:
The patent uses standard floating gate transistors that are already present in the circuit (often used for memory functions) rather than adding specialized long-lived polarizing elements. These transistors serve their primary function and simultaneously provide attack detection, eliminating the need for separate detection components that would require maintenance and calibration.
2Object-affected harmful factors
If metallic layers and transistors are used for protection against charged particle beams, then some protection is provided, but detection reliability is insufficient for advanced technologies
Solution Approach 1:
The floating gate transistors serve dual purposes: their primary function (memory or logic operation) and the detection function. The transistors automatically detect attacks through their inherent charge storage capability, eliminating the need for separate protection and detection systems. The detection is self-service because the same transistor structure that stores data also detects threshold voltage changes caused by charged particle attacks.
Solution Approach 2:
The patent makes the floating gate transistors multi-functional by having them perform both their original function (data storage or logic) and attack detection simultaneously. This universal approach eliminates the need for dedicated protection circuits in advanced technologies, as the existing transistor infrastructure is repurposed for dual functionality.
3Loss of information
If reverse engineering is performed on powered-off integrated circuits, then data recovery is enabled, but detection and preservation of attack evidence becomes difficult
Solution Approach 1:
The patent implements preliminary action by configuring the floating gate transistors with specific initial threshold voltages before the circuit is powered on. This preliminary configuration creates a baseline state that can be compared against later readings. When charged particles attack the circuit during reverse engineering, they alter the transistor thresholds, and this change is detected by comparing against the pre-established initial threshold, enabling evidence preservation even when the circuit is powered off during analysis.
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 enables reliable detection and tracking of attacks on integrated circuits by electrically charged particles, compatible with advanced technologies, and prevents attempts to circumvent detection by reconfiguring charges, ensuring effective countermeasures can be triggered when the circuit is powered.
Implementation Method 1
when an integrated circuit is struck by a beam of electrically charged particles, particularly in scanning electron microscopy or with a focused ion probe, the charges are collected by electrically conductive materials. The charges on the floating gates of the state-state transistors coupled to these electrically conductive materials vary relative to the quantity and polarization of the collected charges
Data Source
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AI summary
The method for detecting an attack on an integrated circuit (IC) by an electrically charged particle beam (IB) comprises: - an embodiment in the integrated circuit of at least one electrically conductive element (MPL) and at least one state transistor having a floating gate (FG) electrically coupled to said at least one electrically conductive element (MPL); - a configuration of said at least one state transistor (FGT) so as to impart to it an initial threshold voltage; and - a detection of said attack by detecting a threshold voltage of said at least one state transistor (FGT) different from the initial threshold voltage (FGT).