Pellicle for EUV
A pellicle for EUV including a silicon film and a mesh work structure supporting the silicon film, and this pellicle is improved in that the grid frames of the mesh work structure are tapered in such a manner that the width of each grid frame lessens as the distance from the silicon film is increased.
1. A pellicle comprising an EUV transmitting silicon film reinforced with a mesh work structure having grid frames, wherein the grid frames of the mesh work structure are tapered such that the width of each grid frame is lessened as the distance from the silicon film is increased and
wherein the taper angle θ, which is formed by a side face of the grid frame and an imaginary vertical wall of the grid frame, lies within the range defined by α×(1+/−0.3), where α is an angle of incidence by which an exposure light passes through the EUV transmitting silicon film.
2. The pellicle for EUV of claim 1 wherein the taper angle θ lies within the range defined by α+/−2 degrees.
3. The pellicle for EUV of claim 1 wherein the taper angle θ lies within the range from 1 to 8.5 degrees.