A self-reparable semiconductor comprises M functional units each including N sub-functional units. Corresponding ones of the N sub-functional units in each of the M functional units perform the same function. At least two of the N sub-functional units in one of the M functional units perform different functions. A first spare functional unit includes X sub-functional units, wherein X is greater than or equal to one and less than or equal to N and wherein the X sub-functional units of. the first spare functional unit are functionally interchangeable with corresponding sub-functional units of the M functional units and wherein the X sub-functional units are provided for the at least two of the N sub-functional units. A plurality of switching devices replace at least one of the N sub-functional units with at least one of the X sub-functional units when the at least one of the N sub-functional units is non-operable.