Integrated Circuit Chip Laser Attack Protection via Gettering Layer
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Solution Overview
Problem
Integrated circuit chips are vulnerable to laser attacks, which can inject faults into memory cells and alter component behavior, and existing protection methods, such as attack detection devices and physical sensors, are not reliable in preventing data acquisition before an attack is detected.
Innovation Solution
A semiconductor substrate with gettering sites containing a high concentration of metal impurities, such as iron atoms, is introduced beneath the active layer to scatter and attenuate laser beams, making it difficult for attackers to inject faults without significantly increasing the laser power and allowing for earlier detection of attacks by conventional means.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If substrate thinning is performed to improve laser attack efficiency, then the laser beam can more easily reach components, but the chip becomes more vulnerable to laser attacks
Solution Approach 1:
The patent introduces a gettering layer containing metal impurities (such as iron) at a specific depth (5-50 μm) beneath the active layer before laser attacks can occur. This preliminary structural modification ensures that when laser attacks are attempted, the beam encounters the metal impurity layer which scatters and attenuates the laser energy, preventing fault injection into the active components.
Solution Approach 2:
The gettering layer with metal impurities acts as an intermediary between the laser beam and the active components. This layer absorbs and scatters the laser energy, serving as a protective barrier that prevents the laser from directly affecting the active layer while maintaining the chip's normal functionality.
2Difficulty of detecting and measuring
If attack detection devices are added to detect laser attacks, then attack detection capability is improved, but critical data can still be acquired before detection
Solution Approach 1:
The patent implements a preliminary protective measure by introducing the metal impurity-containing gettering layer that actively counteracts laser attacks before they can compromise security. This layer physically blocks and scatters laser beams, preventing fault injection and creating detectable disturbances that enable earlier attack detection, thereby eliminating the time window during which attackers could acquire critical data.
3Difficulty of detecting and measuring
If physical sensors are implemented to detect attacks, then attack detection is improved, but the solution becomes complex and increases silicon surface area
Solution Approach 1:
The patent repurposes the existing gettering layer, which is normally used for metal impurity management during manufacturing, to serve a dual function: maintaining semiconductor crystal quality and providing laser attack protection. This eliminates the need for separate detection sensors and additional circuitry, reducing device complexity while maintaining effective attack detection and prevention capabilities.
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
The solution effectively prevents attackers from acquiring critical data before detection by increasing the laser beam power requirements and scattering the beam, thereby enhancing the security of integrated circuit chips without modifying the chip circuits or manufacturing process, and does not increase the silicon surface area.
Implementation Method 1
an area (23) capable of scattering a laser beam... In area 23, gettering sites capable of retaining metal impurities have been formed. Area 23 comprises a strong concentration of intentionally introduced metal impurities, for example, iron, nickel, copper, or gold atoms.
Implementation Method 2
the provision of a contaminated gettering area makes it difficult for an attacker to control the size and the position of the laser beam at the level of the active chip area. Further, the metal impurities enable to diffract/scatter/attenuate a possible attack laser beam
Data Source
AI summary
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 components are formed; and under the active portion and at a depth ranging between 5 and 50 μm from the upper surface of the substrate, an area comprising sites for gettering metal impurities and containing metal atoms at a concentration ranging between 1017 and 1018 atoms/cm3.