Buried Channel Laser Detection Cell for IC Protection
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Solution Overview
Problem
Existing laser detection devices for integrated circuits are ineffective against certain types of laser attacks and occupy a large chip area, limiting their effectiveness and functionality.
Innovation Solution
A laser detection device with a buried channel of a first conductivity type in a substrate of a second conductivity type, coupled to a detection circuit that detects voltage falls, featuring a high resistance path and a transistor with a control node connected to the detection circuit, allowing for sensitive detection of laser pulses without significantly increasing chip area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing laser detection devices are used, then laser attack detection capability is provided, but chip area occupied is relatively large
Solution Approach 1:
The patent moves the detection function from the surface level to a buried channel structure at depth, utilizing the vertical dimension of the substrate. The buried channel is formed at a depth of at least 3 μm below the surface, allowing detection without occupying surface chip area, thus resolving the contradiction between detection capability and chip area occupation.
Solution Approach 2:
The detection function is nested within the substrate structure itself through the buried channel, which is embedded deep within the substrate. This nested approach allows the detection device to be integrated into the existing substrate without adding significant area, as the detection channel is contained within the substrate volume rather than occupying surface space.
2Reliability
If existing laser detection devices are used, then detection function is provided, but effectiveness against certain laser attacks is insufficient
Solution Approach 1:
The patent changes the physical parameters of the detection structure by forming a buried channel at a specific depth (at least 3 μm) with controlled dimensions (width equal to or less than 1.5 μm). This parameter change positions the detection channel in a region less susceptible to certain laser attack vectors while maintaining sensitivity to genuine attacks, thereby improving effectiveness against specific attack types.
3Measurement precision
If detection sensitivity is increased, then short laser pulses can be detected, but device complexity increases
Solution Approach 1:
The patent extracts the detection function from complex surface-level circuitry and isolates it to a simple buried channel structure. By removing unnecessary surface components and concentrating the detection function in the subsurface channel, the design achieves high sensitivity for short pulse detection while actually reducing overall device complexity compared to surface-based detection schemes.
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 enables effective detection of short laser pulses with high sensitivity, allowing for a high density of detection devices without reducing available chip area for other circuit functions, effectively protecting integrated circuits from laser attacks.
Implementation Method 1
A fraudster attempting to access the sensitive data may use a laser, generally applied to the back side of the integrated circuit, to introduce electrical disturbances in the circuit during its operation
Data Source
AI summary
A laser detection device can be used to protect an integrated circuit. The device includes a detection cell having a buried channel of a first conductivity type extending in a substrate of the integrated circuit. The substrate is of a second conductivity type. The detection cell also has a first electrical connection coupling a first point in the buried channel to a supply voltage rail, and a second electrical connection coupled to a second point in the buried channel. A detection circuit is coupled to the second point in the buried channel via the second electrical connection and adapted to detect a fall in the voltage at the second point.