With the shrinking of devices, aggressive OPC is becoming imperative. Generally, OPC must be kept within photomask
manufacturing limits, but at process and OPC development stages, patterns exceeding photomask manufacturing and
inspection limits are often included. To resolve this issue, MRC (Mask Rule Checking) is executed as a method to verify
patterns exceeding photomask manufacturing and inspection limits. Two options are available in MRC to solve errors:
(1) repair layout (or OPC) of corresponding areas; or (2) manufacture photomask including corresponding areas but with
no inspection. Option (1) is generally extremely time-consuming, and if lithographically feasible, (2) would be selected.
However, if detected error flags become massive, it is nearly beyond human control to take care of configurations of
DNIR(Do Not Inspect Region). In addition, massive amounts of DNIR will augment inspection tool setup time almost
factorial. Further, inspection tools have limitations in DNIR setup method, and DNIR settings that do not meet criteria
will be considered as setting violations. Therefore, we developed TLDD (Toppan Layout Driven DNIRs), a tool that
automatically generates DNIR based on detected by MRC. This tool has the following features: (1) applies limitations to
the number of DNIRs; (2) follows DNIR limitations of inspection tools; and (3) follows both (1) and (2) upon which
DNIR area is minimized as much as possible. By utilizing this tool, difficult-to-inspect regions can be automatically set
as DNIR independent of DNIR rules of inspection tools or individual operator skills, while enabling inspection of
important areas at high sensitivity.