 Sometimes a feature pattern inherently contains more than one pitch, and furthermore, these pitches are incompatible to the extent that no illumination can simultaneously image both pitches satisfactorily.A common example, again from DRAM, is the brick pattern defining the active regions of the array.In addition to the narrow pitch of the active regions, there is also the pitch between the active region separations or breaks, which is double that of the narrow pitch in the same direction.