Gettering Area for Laser Attack Protection in Integrated Circuits
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Solution Overview
Problem
Existing methods for protecting integrated circuit chips against laser attacks are inadequate, as they either fail to detect attacks before critical data is compromised or require complex and unreliable physical detection solutions, and existing attack detection systems are not perfectly reliable, allowing attackers to obtain sensitive information before detection.
Innovation Solution
A method involving the formation of a gettering area in the semiconductor substrate with a high concentration of metal impurities, such as iron, to scatter and attenuate laser beams, preventing them from reaching the active chip components, and extending this area under the active portion of the chip to a depth of 5-50 μm from the surface, using techniques like deep implantation of rare gases and anneal steps to create sites that retain metal impurities and diffract laser beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If logical attack detection solutions are implemented, then attack detection capability is improved, but chip response times increase due to additional calculation steps
Solution Approach 1:
The patent replaces logical/software-based attack detection mechanisms with a physical/optical detection mechanism. A detector sensitive to laser radiation is integrated into the chip, enabling direct physical detection of laser attacks without requiring complex logical analysis or calculation steps, thus maintaining fast response times while improving detection capability.
2Reliability
If physical attack detection solutions with sensors are implemented, then attack detection capability is improved, but device complexity and silicon surface area increase
Solution Approach 1:
The patent uses a thin-film detector structure that can be integrated into the chip substrate. This thin-film approach reduces the physical footprint and complexity compared to bulk sensor implementations, allowing effective laser attack detection while minimizing impact on chip architecture and manufacturing complexity.
3Ease of operation
If substrate thinning is performed to improve laser attack efficiency, then laser beam accessibility to components is improved, but chip security against laser attacks deteriorates
Solution Approach 1:
The patent introduces an intermediary layer between the laser beam and the active components. A gettering layer containing metal impurities (such as iron) is positioned between the substrate surface and the active region, serving as a mediator that scatters and absorbs laser radiation, thereby protecting components while still allowing the substrate to be thinned for attack detection purposes.
Solution Approach 2:
The patent converts the harmful effect of metal impurities (which typically degrade semiconductor performance) into a beneficial security feature. By intentionally introducing metal impurities into a gettering layer, the patent creates a protective barrier against laser attacks, transforming what is normally considered a defect into a security enhancement.
4Object-affected harmful factors
If gettering area with metal impurities is formed, then laser beam scattering and attenuation is improved, but manufacturing process complexity increases
Solution Approach 1:
The patent merges the security function (laser protection via gettering layer) with existing semiconductor manufacturing processes. The gettering layer is formed using standard implantation and annealing techniques already employed in CMOS fabrication, combining security enhancement with manufacturing simplicity and avoiding the need for entirely new process equipment or methods.
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 significantly increases the power required for an attacker to inject faults into the chip, making it easier to detect attacks and preventing unauthorized access to critical data, while being compatible with existing manufacturing processes and not increasing the silicon surface area, thus enhancing the security of integrated circuit chips.
Implementation Method 1
introducing diffusing metal impurities into the substrate... metal impurities... to scatter and attenuate laser beams
Implementation Method 2
create sites that retain metal impurities and diffract laser beams
Implementation Method 3
forming in the substrate a gettering area... introducing diffusing metal impurities into the substrate
Implementation Method 4
introducing diffusing metal impurities into the substrate
Implementation Method 5
using techniques like deep implantation of rare gases and anneal steps to create sites that retain metal impurities
Data Source
AI summary
A method for protecting, against laser attacks, an integrated circuit chip formed inside and on top of a semiconductor substrate and including in the upper portion of the substrate an active portion in which are formed components, this method including the steps of: forming in the substrate a gettering area extending under the active portion, the upper limit of the area being at a depth ranging between 5 and 50 μm from the upper surface of the substrate; and introducing diffusing metal impurities into the substrate.