On Quartz substrate, Cr/CrO2 layer is formed by sputtering, followed by PR coating on top of it.
Using E-Beam or Laser lithography equipment, a certain pattern is written on the surface of the PR layer.
Using developer (chemicals), the pattern formation is finalized over the PR area which was exposed by the lithography equipment.
Using either dry or wet etching technique, the exposed Cr/CrO2 layer is etched to reveal the Quartz surface. The area covered by PR is unaffected.
Remaining PR is removed via strip process, followed by clean and dry steps. At this stage, the photomask surface is composed of dark or clear area (dark area is still covered by Cr/CrO2 whereas clear area is naked Quartz, which transmits incoming light source.
CD measurement is performed over the Dark or Clear space patterns.
Positional accuracy of key patterns are measured.
Defects are identified and necessary repair work is performed in order to ensure confirmation to the design.
Particles are removed during cleaning step.
Pellicle is mounted over the finished side of Quartz plate in order to prevent potential contamination.
