Backside Attack Detection in Electronic Chips
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Solution Overview
Problem
Electronic chips are vulnerable to attacks that exploit the backside, allowing unauthorized access and extraction of confidential information by etching cavities and dismantling protection mechanisms before countermeasures can be triggered.
Innovation Solution
The chip design features conductive pads on the front side with cavities etched from the backside, covered by a conductive layer with protrusions, and an insulating material, allowing for detection of electric characteristics and triggering countermeasures upon connection disruption, while the insulating layer's low etch selectivity and opaque properties hinder unauthorized access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the backside of the chip is etched to access active portions, then unauthorized access and information extraction are enabled, but the chip's security protection is compromised
Solution Approach 1:
The patent implements a detection circuit that continuously monitors the integrity of conductive paths before an attacker can complete their exploitation. The system performs preliminary detection of any etching or manipulation attempts on the backside conductive layers, triggering security responses before confidential information can be extracted. This transforms the security model from reactive to proactive, addressing the vulnerability to backside attacks.
Solution Approach 2:
The patent employs a feedback mechanism where the detection circuit continuously monitors the electrical characteristics of conductive paths and provides real-time feedback about their integrity. When changes are detected that indicate unauthorized access attempts, the system immediately triggers countermeasures. This closed-loop feedback system enables the chip to respond dynamically to security threats, preventing information extraction even when physical access is obtained.
2Ease of operation
If conductive layers are made accessible on the backside for connectivity, then electrical connection between cavities is achieved, but vulnerability to etching attacks increases
Solution Approach 1:
The detection circuit is configured to monitor the integrity of backside conductive layers before attackers can exploit them. By continuously checking electrical characteristics, the system detects any etching or manipulation attempts on the conductive paths that connect cavities, triggering security responses before the attack can succeed. This preliminary detection capability protects the electrical connectivity while mitigating the associated security risk.
Solution Approach 2:
The patent introduces an intermediary detection and control system between the backside conductive layers and the confidential information they protect. This intermediary layer monitors the electrical characteristics of conductive paths and can trigger security responses that prevent information extraction, even when physical access to the conductive layers is obtained. The intermediary acts as a security gatekeeper that preserves connectivity while blocking malicious exploitation.
3Reliability
If protection devices are placed on the backside to detect attacks, then security monitoring is improved, but the chip structure becomes more complex
Solution Approach 1:
The patent implements a multi-functional detection circuit that performs multiple security functions using a single integrated structure. The same conductive layers and cavities that provide electrical connectivity also serve as the monitoring elements for detecting attacks. The detection circuit leverages the existing backside structure rather than adding separate protection devices, thereby improving security monitoring while minimizing increases in structural complexity.
Solution Approach 2:
The patent merges the connectivity function and security monitoring function into a single integrated system. The conductive layers that connect cavities for electrical operation are simultaneously used as the sensing elements for detecting etching or manipulation attempts. By combining these functions rather than implementing separate protection devices, the patent achieves improved security monitoring with minimal additional structural complexity.
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 unauthorized access by detecting and responding to connection disruptions, ensuring the chip's security and integrity even if the insulating layer is removed, as the conductive layer's portions on protrusions are designed to be quickly etched, making it difficult for attackers to distinguish and reconnect correctly.
Implementation Method 1
A method of pirating information manipulated by integrated circuits comprises etching the backside of the chip, for example, by chemical etching or by chemical-mechanical polishing.
Implementation Method 2
A method of pirating information manipulated by integrated circuits comprises etching the backside of the chip, for example, by chemical etching or by chemical-mechanical polishing.
Implementation Method 3
the circuit is capable of measuring the resistance between pads and each pad is directly connected to the conductive layer
Implementation Method 4
the circuit is capable of measuring the capacitance between pads, and each pad is separated from the conductive layer by a first layer of insulating material
Data Source
AI summary
An electronic chip includes a substrate made of semiconductor material. Conductive pads are located on a front side of the substrate and cavities extend into the substrate from a backside of the substrate. Each cavity reaches an associated conductive pad. Protrusions are disposed on the backside of the substrate. A conductive layer covers the walls and bottoms of the cavities. The conductive layer includes portions on the backside, each portion partially located on an associated protrusion and electrically connecting two of the conductive pads.