A method for improving yield of a process for fabricating a read-only
memory (ROM) includes evaluating a yield of a ROM fabrication process
associated with a first ROM design. At least two candidate ROM design
modifications are identified. At least one of the candidate ROM design
modifications comprises inversion of bit values of data to be stored in
the ROM. A plurality of criteria are applied, including at least an
amount of yield improvement and a difficulty of implementation associated
with each candidate ROM design modification. One of the candidate ROM
design modifications is selected based on the application of the
criteria. A modified ROM fabrication process is performed to fabricate a
ROM according to the selected ROM design modification.