Embedded Substrate Thickness Sensing for Backside Thinning Detection
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Solution Overview
Problem
Existing security features for integrated circuit (IC) chips do not effectively address attacks involving backside thinning, which can facilitate Laser Fault Injection (LFI) attacks by allowing malicious access to the transistor area.
Innovation Solution
An IC device with embedded charge emitters and sensors that detect semiconductor substrate thickness changes by generating and measuring electrical charges, allowing for internal detection of substrate thinning without external devices, thereby enhancing security measures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional security features are used, then basic security is provided, but they cannot detect backside thinning attacks
Solution Approach 1:
The semiconductor substrate itself serves as the detection medium by generating charge carriers when exposed to light. The substrate's own electrical properties are utilized to detect thickness changes, eliminating the need for separate external detection systems and enabling the device to monitor its own structural integrity
Solution Approach 2:
The patent replaces mechanical thickness measurement methods with an electrical detection system. Instead of using physical probes or external measurement devices, the system uses electrical charge detection through photogenerated carriers to indirectly measure substrate thickness, enabling non-contact and integrated monitoring
2Measurement precision
If external detection devices are used, then substrate thickness can be monitored, but device complexity and area overhead increase
Solution Approach 1:
The detection functionality is merged with the existing semiconductor substrate structure. The charge emitter and sensor are integrated within the substrate itself, combining the detection function with the device's core structure rather than adding separate external components, thereby reducing overall device complexity
Solution Approach 2:
The semiconductor substrate serves multiple functions: it acts as both the functional device substrate and the detection medium. The same substrate material that forms the device also generates the charge carriers used for thickness detection, eliminating the need for dedicated separate detection components
3Measurement precision
If external detection devices are used, then substrate thickness can be detected, but power consumption increases
Solution Approach 1:
The substrate generates its own charge carriers through photogeneration when exposed to light, eliminating the need for external power-intensive measurement equipment. The detection process utilizes the substrate's own electrical properties and requires minimal additional power for signal readout
Solution Approach 2:
The patent replaces power-intensive mechanical or external electrical measurement systems with a passive optical excitation method. Light exposure generates charge carriers without requiring continuous power input, and the electrical readout requires minimal power compared to external detection devices
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 provides robust, embedded substrate thickness detection, enabling the IC device to trigger security actions and thwart attacks by accurately monitoring and responding to changes in substrate thickness, reducing silicon area overhead, computation time, and power consumption.
Implementation Method 1
a charge emitter embedded in the semiconductor substrate and configured to produce an electrical charge in the semiconductor substrate when exposed to light
Implementation Method 2
a charge sensor embedded in the semiconductor substrate and configured to generate a response signal in response to the electrical charge produced in the semiconductor substrate
Data Source
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AI summary
Embodiments of devices and method for detecting semiconductor substrate thickness are disclosed. In an embodiment, an IC device includes a semiconductor substrate, a charge emitter embedded in the semiconductor substrate and configured to produce an electrical charge in the semiconductor substrate and a charge sensor embedded in the semiconductor substrate and configured to generate a response signal in response to the electrical charge produced in the semiconductor substrate. The magnitude of the response signal depends on the thickness of the semiconductor substrate.