Digital circuit with transistor geometry and channel stops providing camouflage against reverse engineering
First Claim
1. A method of fabricating a camouflaged digital integrated circuit (IC), comprising:
- implanting an array of transistors in a substrate, implanting common patterns of electrically conductive doped interconnections among said transistors, andinterrupting some of said interconnections in a manner that is not readily visibly perceptible to implement different logic functions for separate groups of transistors that have common transistor sizes and layouts.
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Accused Products
Abstract
An integrated digital circuit is protected from reverse engineering by fabricating all transistors of like conductivity 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 in the substrate rather than metalized interconnections, and providing non-functional apparent interconnections that are interrupted by non-discernable channel stops so that all cells falsely appear to have a common interconnection scheme. The camouflage is enhanced by providing a uniform pattern of metal leads over the transistor array, with a uniform pattern of heavily doped implant taps from the transistors for connection to the leads; undesired tap-lead connections are blocked by channel stops.
119 Citations
9 Claims
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1. A method of fabricating a camouflaged digital integrated circuit (IC), comprising:
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implanting an array of transistors in a substrate, implanting common patterns of electrically conductive doped interconnections among said transistors, and interrupting some of said interconnections in a manner that is not readily visibly perceptible to implement different logic functions for separate groups of transistors that have common transistor sizes and layouts. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification