Pellicle

The Pellicle is a protective membrane mounted a few milimters above the surface of the mask to hold fall-on particles out fo the focal plane. 

 

EUV: 13.5nm, 

The full pellicle size : 117 mm x 151mm

 

Manufacturing

 

 1) Approach 1 : As low as possible photo absorption cross-section. 

 - SiNx : Sputtering?

 

 2) Approach 2 : The film with ow Density

 - CNT : CVD

 

1) Fluoropolymers : by spin-coated.

2) SiC

3) p-Si and SiNx  (the film thickness is about 50nm(p-Si) an d 20nm(SiNx).

 

Requirements

 

 1. have a high(average) transmission, but also good transmittion uniformity.

 2. be mechanically stable

 3. be resistant to high thermal loads.

 4. be chemiccaly stable in 'EUV+H2' environment

 5. enable large scale area fabrication (aspect ratio of pellicle length/ thickness is > 10^6