| Popis: |
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. |
