Integrated Circuit Substrate Thinning Detection via Resistance Measurement
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Solution Overview
Problem
Integrated circuits, particularly those with sensitive information, face security threats when the substrate is thinned from the back face, allowing attackers to access internal components, and existing methods lack effective detection mechanisms.
Innovation Solution
The integration of electrically-conducting contacts within insulating regions of the integrated circuit allows for the measurement of resistance changes as the substrate is thinned, using existing etch operations and a detector circuit to signal substrate thinning, without increasing surface area or disrupting conventional fabrication processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the substrate is thinned from the back face to access internal components, then the efficiency of the attack increases, but the security of the integrated circuit deteriorates
Solution Approach 1:
The patent implements detection contacts and measurement circuits during the fabrication process, before the integrated circuit is deployed. This preliminary action enables early detection of substrate thinning attacks, allowing the system to identify security breaches before they can compromise sensitive information
Solution Approach 2:
The patent establishes a feedback mechanism where the resistance measurement from detection contacts provides real-time information about substrate integrity. When the substrate is thinned during an attack, the resistance changes, providing feedback that signals the attack is occurring, enabling immediate response
2Difficulty of detecting and measuring
If detection contacts are added to the integrated circuit, then the detection capability improves, but the surface area occupied increases
Solution Approach 1:
The patent merges the detection contacts with existing insulating regions (such as shallow trench isolation structures) that are already present in the integrated circuit fabrication process. By forming detection contacts within these pre-existing insulating regions, the patent adds detection functionality without requiring additional surface area beyond what is already allocated for isolation structures
Solution Approach 2:
The insulating regions serve dual purposes: they provide electrical isolation between circuit components (their original function) and simultaneously host detection contacts for substrate thinning detection (new function). This multi-functionality allows the same physical space to serve both traditional isolation purposes and security detection purposes
3Measurement precision
If additional contacts are formed in insulating regions, then the detection precision improves, but the manufacturing complexity increases
Solution Approach 1:
The patent performs the formation of detection contacts during standard fabrication steps, specifically utilizing etch operations that are already scheduled in the manufacturing process. By integrating detection contact formation into existing etch steps rather than adding separate processing steps, the patent avoids increasing manufacturing complexity
Solution Approach 2:
The patent combines the formation of detection contacts with the formation of other circuit features that require similar processing steps. The etch operations used to create detection contact openings are merged with etch operations used for other fabrication purposes, allowing multiple features to be created simultaneously through unified processing sequences
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 provides a compact and effective detection method for substrate thinning, enabling early detection of potential attacks and preventing unauthorized access by measuring resistance changes between contacts, thereby enhancing security without altering the surface area or conventional fabrication processes.
Implementation Method 1
a measurement is provided of a physical quantity representative of the resistance between the ends of the two electrically-conducting contacts
Data Source
AI summary
The thinning of a semiconductor substrate of an integrated circuit from a back face is detected using the measurement of a physical quantity representative of the resistance between the ends of two electrically-conducting contacts situated at an interface between an insulating region and an underlying substrate region. The two electrically-conducting contacts extend through the insulating region to reach the underlying substrate region.