Mask Process
On Quartz substrate, Cr/CrO2 layer is formed by sputtering, followed by PR coating on top of it.
Using 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 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.
在Mask上測定pattern之position accuracy。
檢驗design pattern以外之defect並進行修正。
透過cleaning去除particle。
為防止污染mask pattern，附蓋pellicle。
