A ferroelectric-type nonvolatile semiconductor memory comprising a plurality
of
bit lines and a plurality of memory cells, a plurality of the memory cells belonging
to one of two or more thermal history groups having different thermal histories
with regard to their production processes, and a reference potential of the same
level is provided to the bit lines connected to the memory cells belonging to the
same thermal history group, and reference potentials of different levels are provided
to the bit lines connected to the memory cells belonging to the different thermal
history groups.
