Reticle inspection issues

Rule-Based Tiling

• Done with Boolean operations

• Only density of the template is variable

• Not adequate for arbitrary design

Model-Based Tiling

RETICLE INSPECTION ISSUES

• Defectivity is the most serious problem affecting reticle delivery

• More acute with the introduction of OPC

• OPC features do not resolve as drawn in the design on reticle

• When inspected, OPC results in vast numbers of false defect detections

• Worst case (currently typical), the mask cannot be inspected at all

• Standard practice:

• De-sense reticle inspection tool so partially resolved OPC shapes do not cause errors
• De-sensing for OPC also de-senses the tool to legitimate defects