Pellicle
Pellicle
Pellicle is a thin film that protects reticle surface from particles in the air or other source of contaminations. Furthermore it makes particles on pellicle surface be out of focus to prevent wafer pattern distortion.
Membrane is attached to the anodized aluminum frame and then firmly attached to reticle.
General structure of Pellicle
Comparison of Pellicle Membranes
| Material | Perfluoro polymer | Cellulose |
|---|---|---|
| Applied exposure wavelength | KrF (193nm) | i-, g-, h- line (365nm~436nm) |
| Transmittance | ≥99% | ≥99% |
| Uniformity of TR | ≤0.2% | ≤0.5% |
| integrated exposure energy | Avg. 500,000J/cm2 | Avg. ≥400,000J/cm2 |
| shot number of exposure (400mJ/cm2가정) |
500,000,000mj/cm2÷ 400mj/cm2 = 1,250,000shots |
400,000,000mj/cm2÷ 400mj/cm2 = 1,000,000shots |