Buried Metal Layers for X-Ray Blocking in IC Packages
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Solution Overview
Problem
Existing integrated circuit technologies are vulnerable to tampering and intellectual property theft through active x-ray spectrum analysis, as current package shielding methods are prone to tampering and unable to prevent the determination of key technology and circuit design functionality.
Innovation Solution
The implementation of multiple buried metal layers, such as metal-insulator-metal capacitors, inductors, and resistors, at the back end of the line (BEOL) to detect and prevent radio frequency or optical probing attacks, including x-ray attacks, by altering capacitance or inductance upon tampering, and utilizing logic circuits to generate tamper signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If package shielding is used to prevent x-ray analysis, then security against active intrusion is improved, but the shielding is still prone to tampering and cannot prevent uncovering of key technology
Solution Approach 1:
The patent moves the security function from the traditional package level (external shielding) to the substrate level (back-end-of-line metal layers embedded within the chip structure). This dimensional shift integrates security directly into the circuit substrate, making tamper detection inherent to the device architecture rather than relying on external protective packaging.
Solution Approach 2:
The back-end-of-line metal layers serve as an intermediary between the circuit devices and the x-ray analysis threat. These metal layers act as a detectable barrier that interrupts x-ray transmission, allowing the system to sense tampering attempts without requiring complex external shielding structures.
2Area of stationary object
If back end of the line metal layers are used to block x-ray, then chip space for front-end devices is improved, but additional security monitoring circuitry is required
Solution Approach 1:
The back-end-of-line metal layers serve dual functions: they provide standard electrical interconnect functionality for the circuit while simultaneously acting as x-ray blocking security elements. This multi-functionality eliminates the need for separate security structures, as the existing BEOl metallization performs both routing and tamper detection roles.
Solution Approach 2:
The security monitoring is achieved by utilizing the inherent electrical properties of the back-end metal layers themselves. The metal layers' capacitance and conductivity characteristics are naturally monitored by the circuit, allowing the structure to self-detect tampering without requiring entirely separate sensing mechanisms.
3Reliability
If multiple buried metal layers are used to detect tampering, then security detection capability is improved, but manufacturing process complexity increases
Solution Approach 1:
The security-sensitive metal layers are formed as part of the standard back-end-of-line manufacturing process, before final packaging and assembly. The metal interconnect structures are created during normal circuit fabrication, and security monitoring capabilities are built into the structure during these preliminary manufacturing stages, avoiding the need for separate post-fabrication security modifications.
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 effectively prevents the determination of circuit design functionality and theft of key technology by 'blinding' attackers with a clear picture of the functional circuit, while also saving chip space for more front-end of the line (FEOL) devices and providing an additional layer of security against localized attacks.
Implementation Method 1
a logic circuit connecting to the plurality of metals via the at least one contact, and which is configured to detect a capacitance change in the backside patterned metal layer
Data Source
AI summary
The present disclosure relates to integrated circuits, and more particularly, to an anti-tamper x-ray blocking package for secure integrated circuits and methods of manufacture and operation. In particular, the present disclosure relates to a structure including: one or more devices on a front side of a semiconductor material; a plurality of patterned metal layers under the one or more devices, located and structured to protect the one or more devices from an active intrusion; an insulator layer between the plurality of patterned metal layers; and at least one contact providing an electrical connection through the semiconductor material to a front side of the plurality of metals.