Interconnect PUF Structures With Random Voids for Stable IC Security
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Solution Overview
Problem
Physical unclonable functions (PUFs) in semiconductor technology are sensitive to environmental conditions such as temperature and process variations, making them unreliable without additional stabilization and error-correction techniques.
Innovation Solution
The integration of PUF structures with random sidewall voids and line openings, and memory structures without sidewall voids and line openings, within the same interconnect level, using a discontinuous diffusion barrier layer in the PUF area and a continuous layer in the memory area, to form stable and reliable conductive structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If physical unclonable functions are implemented using standard interconnect structures, then manufacturing process is simplified, but reliability is reduced due to environmental sensitivity
Solution Approach 1:
The patent applies local quality by creating distinct interconnect structures in different regions: PUF structures with random sidewall voids and line openings in the PUF area, and solid interconnect structures without voids in the memory area. This regional differentiation allows the PUF structures to exhibit environmental sensitivity for generating unique identifiers, while memory structures maintain stability for reliable data storage, thus resolving the contradiction between manufacturing simplicity and reliability.
2Reliability
If additional stabilization and error-correction techniques are applied to PUFs, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent converts the harmful effect of environmental sensitivity into a beneficial feature by intentionally designing PUF interconnect structures with random sidewall voids and line openings that exploit manufacturing variations. These variations, which would normally be considered defects reducing reliability, are instead harnessed to generate unique, unclonable identifiers. This eliminates the need for additional stabilization and error-correction techniques, resolving the contradiction between reliability improvement and device complexity.
3Reliability
If PUF structures are made highly reliable through process modifications, then additional masks and processes are required, but manufacturing complexity increases
Solution Approach 1:
The patent merges the PUF structure formation with the standard interconnect formation process. By integrating PUF structures with random sidewall voids and line openings directly into the existing interconnect levels using the same manufacturing steps (deposition, etching, and material removal processes), the patent achieves reliable PUF output without requiring additional masks or process steps. This integration resolves the contradiction between PUF reliability and manufacturing complexity.
Data Source
AI summary
An integrated circuit (IC) is provided that includes a plurality of physical unclonable function (PUF) structures located in a PUF area. Each PUF structure of the plurality of PUF structures includes at least a PUF top electrically conductive structure containing random sidewall voids and random line openings which can provide an encrypted security code to the IC. The IC further includes a plurality of memory structures located in a memory area that is located laterally adjacent to the PUF area. Each memory structure of the plurality of memory structures includes a memory element sandwiched between a bottom electrically conductive structure and a top electrically conductive structure. The top electrically conductive structures are devoid of sidewall voids and line openings.