A self-reparable semiconductor includes multiple functional units that perform the same function and that include sub-functional units. The semiconductor includes one or more full or partial spare functional units that are integrated into the semiconductor. If a defect in a sub-functional unit is detected, then that sub-functional unit is switched out and replaced with a sub-functional unit in the full or partial spare functional unit. The reconfiguration is realized with switching devices that are associated with the sub-functional units. Defective functional or sub-functional units can be detected after assembly, during power up, periodically during operation, and/or manually.