Abstract: This invention relates to Multiple Interlocked Cells (MICE) design as a hardening technique for CMOS logic gates consisting of two or more redundant nodes with node isolation components. This technique is used to modify existing standard CMOS logic gates or create new complex logic gates using common mask layers existing at ultra-deep sub-micron CMOS foundries. For single node upset immunity in logic or register, a primary cell and a redundant cell are used. For multi-node immunity, the primary cell is combined with two or more redundant nodes are used with physical layout spacing techniques which will insure that a single particle track cannot upset all three nodes simultaneously, and logic circuits built using this technique are immune to upsets in any environment. Circuits built using the MICE technique are also immune to single event transients without requiring the large time delays used in other hardening techniques.