Pellicle for EUV, and an assembly including the pellicle, and a method for assembling the same

摘要

Here are disclosed a pellicle for EUV and an assembly made up of this pellicle and a mask, which brings about a projection of low contrast (intensity) shadows of a mesh structure on the mask, thus minimizing the adverse effect of the shadow on the lithographic printing; also a method for assembling such assembly is disclosed wherein the pellicle is rotated relative to the mask to minimize the shadow contrast, in terms of a contrast ratio, of the mesh structure; the angle of the rotation is 30 degrees or smaller, and the resultant contrast ratio should be 25% or lower.

主权项

1. A pellicle for EUV which comprises: (i) a pellicle membrane structure having a pellicle membrane and a mesh structure, the latter reinforcing the former, and (ii) a pellicle frame for holding the pellicle membrane structure, the mesh structure being disposed to be projected in two kinds of image shadow on a wafer on account of EUV light's passing the EUV pellicle twice as it approaches and reflects on a pattern-carrying face of a mask; wherein a stand-off of the pellicle is of such a value as to allow the contrast ratio between the two kinds of image shadow of the mesh structure to be 25% or lower.