Symmetric PUF Cell Array Layout for Bias-Resistant Randomness

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Solution Overview

Problem

Integrated circuits with Physically Unclonable Functions (PUFs) face performance issues due to systematic biases in the PUF output, which affect the desired randomness and security.

Innovation Solution

A PUF cell array is designed with symmetric and balanced architectures, where each PUF cell has a set of conductive structures on a metal layer, and the address of each PUF cell is randomly arranged to minimize systematic bias.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If PUF cells are arranged in a regular grid pattern, then manufacturing and design are simplified, but systematic biases occur in the PUF output affecting randomness and security

Engineering Contradiction:

ImprovePUF cell array fabrication simplicityVSAvoidPUF output randomness and security

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies asymmetry by randomly arranging PUF cell addresses rather than using a regular grid pattern. Specifically, the address assignment to physical locations is performed randomly, breaking the systematic symmetry that causes biases. This randomization ensures that no particular region of the chip dominates the PUF output, thereby improving randomness and security while maintaining manufacturability through standard fabrication processes

Inventive Principle:

Principle #4Asymmetry

2Ease of operation

If PUF cell addresses are assigned systematically, then addressing and control are simplified, but regional biases affect PUF performance and output quality

Engineering Contradiction:

ImprovePUF cell addressing simplicityVSAvoidPUF output uniformity and randomness

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent inverts the conventional approach by randomly assigning addresses to physical locations rather than systematically mapping addresses to positions. This inversion means that the address-to-location mapping is no longer deterministic or sequential, but rather random. This approach maintains ease of operation through software-based address management while dramatically improving output uniformity by eliminating regional biases that would otherwise dominate the PUF response

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS20250124209A1PUF cell array, system and method of manufacturing same

Publication Date: 2025.04.17 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

A physically unclonable function (PUF) cell array includes a first PUF cell in a first column in a first direction, and a second PUF cell in a second column. The first PUF cell includes a first set of conductive structures that include a first conductive structure extending in the second direction and a second conductive structure extending in the first direction. The second PUF cell includes a second set of conductive structures that include a third conductive structure extending in the second direction and a fourth conductive structure extending in the first direction. At least the first and third conductive structure, or the second and the fourth conductive structure are symmetric to each other with respect to a central line between the first or second PUF cell.