A New Paradigm in Split Manufacturing: Lock the FEOL, Unlock at the BEOL

Abhrajit Sengupta, Mohammed Nabeel, Mohammed Ashraf, Johann Knechtel, Ozgur Sinanoglu

Research output: Contribution to journalArticlepeer-review


Split manufacturing was introduced as a countermeasure against hardware-level security threats such as IP piracy, overbuilding, and insertion of hardware Trojans. However, the security promise of split manufacturing has been challenged by various attacks which exploit the well-known working principles of design tools to infer the missing back-end-of-line (BEOL) interconnects. In this work, we define the security of split manufacturing formally and provide the associated proof, and we advocate accordingly for a novel, formally secure paradigm. Inspired by the notion of logic locking, we protect the front-end-of-line (FEOL) layout by embedding secret keys which are implemented through the BEOL in such a way that they become indecipherable to foundry-based attacks. At the same time, our technique is competitive with prior art in terms of layout overhead, especially for large-scale designs (ITC’99 benchmarks). Furthermore, another concern for split manufacturing is its practicality (despite successful prototyping). Therefore, we promote an alternative implementation strategy, based on package-level routing, which enables formally secure IP protection without splitting at all, and thus, without the need for a dedicated BEOL facility. We refer to this as “poor man’s split manufacturing” and we study the practicality of this approach by means of physical-design exploration.

Original languageEnglish (US)
Article number22
Issue number2
StatePublished - Jun 2022


  • logic locking
  • proximity attack
  • split manufacturing

ASJC Scopus subject areas

  • Software
  • Applied Mathematics
  • Computer Networks and Communications
  • Computer Science Applications
  • Computational Theory and Mathematics


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