A semiconductor substrate is provided by a method suitable for mass production. The fan blade unit comprises a fan head and a plurality of fan blades arranged radially thereto. The exposed portion of the active region is etched to define a preliminary gate trench therein including opposing sidewalls and a surface therebetween, where portions of the mask pattern extend to edges of the active region outside the preliminary gate trench. Thereby, modules cannot be easily analyzed and program tamper resistance can be improved. An insulating layer is formed over the memory array. Large area geometries may be located by a two-step process that generates a pattern definition by defining smaller patterns therein and by defining the spatial relationships of the smaller patterns.