Isolated Semiconductor Well Detection for DFA and Substrate Thinning
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Solution Overview
Problem
Integrated circuits face challenges in detecting substrate thinning from the rear face and Differential Fault Analysis (DFA) attacks, which can compromise their security and functionality.
Innovation Solution
A method and integrated circuit design that incorporates a second semiconductor well insulated from the first well, with a detection device capable of detecting substrate thinning by measuring electrical resistance and fault injection, allowing for simultaneous protection against both threats without interfering with the components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate detection device for substrate thinning is implemented, then detection capability is improved, but device complexity and surface area increase
Solution Approach 1:
The patent combines substrate thinning detection and DFA attack detection into a single integrated detection device formed in the second semiconductor well. This merging of functions reduces device complexity and surface area while maintaining both detection capabilities through unified measurement of current flow in the isolated well
Solution Approach 2:
The detection device in the second semiconductor well serves multiple functions: it detects both substrate thinning attacks and DFA attacks by monitoring current flow. This multi-functional approach eliminates the need for separate detection devices, reducing overall system complexity
2Area of stationary object
If the detection device is placed close to components, then surface area is reduced, but interference effects from components increase
Solution Approach 1:
The detection device is extracted into an isolated second semiconductor well that is electrically separated from the first semiconductor well containing the circuit components. This spatial and electrical separation removes interference from components while keeping the detection device within the integrated circuit structure
Solution Approach 2:
The patent introduces an intermediate isolated well structure that acts as a mediator between the circuit components and the detection function. This intermediate structure provides electrical isolation through the substrate, blocking interference from components while allowing the detection device to function
3Measurement precision
If components are disabled during detection, then detection accuracy is improved, but productivity and ease of operation deteriorate
Solution Approach 1:
The detection device is extracted into an isolated second well that is electrically separated from the circuit components. This isolation allows continuous operation of components during detection without interference, eliminating the need to disable components and maintaining full productivity
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 detects substrate thinning and DFA attacks, reducing the surface area requirements and avoiding interference from integrated circuit components, thereby enhancing security and efficiency.
Implementation Method 1
detecting a thinning of the substrate via its rear face by a detection of the absence of current flowing in the second well
Implementation Method 2
in the case of detection of a non-thinning of the substrate, detecting a DFA attack by the detection of the flow of a current flowing in the second well
Data Source
AI summary
An integrated circuit includes a semiconductor substrate having a rear face. A first semiconductor well within the substrate includes circuit components. A second semiconductor well within the substrate is insulated from the first semiconductor well and the rest of the substrate. The second semiconductor well provides a detection device that is configurable and designed to detect a DFA attack by fault injection into the integrated circuit.