Camouflaged digital circuit with transistor geometry and channel stops and manufacturing method thereof

摘要

An integrated digital circuit is protected from reverse engineering by fabricating all transistors of like conductivity (2, 4, 6, 30; 12, 14, 16, 32) with a common size and geometric layout, providing a common layout for different logic cells, connecting doped circuit elements of like conductivity with electrically conductive doped implants (C) in the substrate (38) rather than metalized interconnections, and providing non-functional apparent interconnections that are interrupted by non-discernable channel stops (CSO) so that all cells falsely appear to have a common interconnection scheme. The camouflage is enhanced by providing a uniform pattern of metal leads (8, 18, 28, 34) over the transistor array, with a uniform pattern of heavily doped implant taps (ST, DT) from the transistors for connection to the leads; undesired tap-lead connections are blocked by channel stops.