Multi-layer pellicle membrane
A pellicle assembly includes a pellicle membrane and a conformal coating on an outer surface of the pellicle membrane. The pellicle membrane can be formed with multiple layers and has a combination of high transmittance, low deflection, and small pore size. The conformal coating is intended to protect the pellicle membrane from damage that can occur due to heat and hydrogen plasma created during EUV exposure.
1 . A pellicle assembly, comprising:
a multi-layer pellicle membrane having an outer surface and an inner surface, wherein the multi-layer pellicle membrane comprises at least a first nanotube membrane layer, a second nanotube membrane layer, and a graphene membrane layer; and
a conformal coating that conforms to exposed surfaces in all layers of the multi-layer pellicle-membrane, wherein the conformal coating comprises ZrF 4 , YF, or HfF 4 .
2 . The pellicle assembly of claim 1 , wherein the first nanotube membrane layer and the second nanotube membrane layer each have a thickness of about 10 nm to about 100 nm.
3 . The pellicle assembly of claim 1 , wherein the second nanotube membrane layer comprises randomly oriented nanotubes or directionally oriented nanotubes.
4 . The pellicle assembly of claim 1 , wherein the conformal coating has a thickness of about 1 nanometer to about 10 nanometers.
5 . The pellicle assembly of claim 1 , further comprising a mounting frame attached to a border which contacts the inner surface of the pellicle membrane.
6 . The pellicle assembly of claim 5 , wherein the mounting frame includes vent holes and the border does not include vent holes.
7 . The pellicle assembly of claim 1 , wherein the pellicle membrane has an EUV transmittance at 13.5 nm of at least 90%, a maximum deflection of 700 μm, and a maximum pore size of 30 nanometers.
8 . A method for producing a reticle assembly comprising:
mounting a pellicle assembly over a mask pattern on a reticle;
wherein the pellicle assembly comprises a multi-layer pellicle membrane having a conformal coating, wherein the multi-layer pellicle membrane comprises at least a first nanotube membrane layer, a second nanotube membrane layer, and a graphene membrane layer, wherein the conformal coating conforms to exposed surfaces in all layers of the multi-layer pellicle membrane, and wherein the conformal coating comprises ZrF 4 , YF, or HfF 4 .
9 . The method of claim 8 , wherein the pellicle membrane has an EUV transmittance at 13.5 nm of at least 90%, a maximum deflection of 700 μm, and a maximum pore size of 30 nanometers.
10 . A method for increasing service lifetime of a pellicle membrane, comprising:
applying a conformal coating to a multi-layer pellicle membrane by spraying or coating, wherein the multi-layer pellicle membrane comprises at least a first nanotube membrane layer, a second nanotube membrane layer, and a graphene membrane layer that forms an outer surface of the pellicle membrane, wherein the graphene membrane layer is a continuous film without pores and wherein the conformal coating conforms to exposed surfaces in all layers of the multi-layer pellicle membrane;
wherein the conformal coating comprises ZrF 4 , YF, or HfF 4 ; and
wherein the conformal coating has a transmittance (T %), when measured at an EUV wavelength of 13.5 nm and at a thickness of between 1 nm and 10 nm, of greater than 90%.
11 . The pellicle assembly of claim 1 , wherein the first nanotube membrane layer comprises randomly oriented nanotubes or directionally oriented nanotubes.
12 . The method of claim 10 , wherein the first nanotube membrane layer and the second nanotube membrane layer each have a thickness of about 10 nm to about 100 nm.
13 . The method of claim 10 , wherein the conformal coating has a thickness of about 1 nanometer to about 10 nanometers.
14 . The method of claim 10 , wherein the nanotubes in the first nanotube membrane layer and the second nanotube membrane layer are boron nitride nanotubes or silicon carbide nanotubes.
15 . The method of claim 10 , wherein the nanotubes in the first nanotube membrane layer and the second nanotube membrane layer are multi-wall nanotubes made of different materials.
16 . The method of claim 8 , wherein the pellicle assembly further comprises a border or a mounting frame contacting the inner surface of the pellicle membrane.
17 . The method of claim 8 , wherein the first nanotube membrane layer and the second nanotube membrane layer each have a thickness of about 10 nm to about 100 nm.
18 . The method of claim 8 , wherein the first nanotube membrane layer and the second nanotube membrane layer each comprise randomly oriented nanotubes or directionally oriented nanotubes.
19 . The method of claim 8 , wherein the conformal coating has a thickness of about 1 nanometer to about 10 nanometers.
20 . The method of claim 8 , wherein the nanotubes in the first nanotube membrane layer and the second nanotube membrane layer are boron nitride nanotubes or silicon carbide nanotubes.