Robust, high transmission pellicle for extreme ultraviolet lithography systems
View Patent ↗A robust, high-transmission pellicle for extreme ultraviolet lithography systems is disclosed. In one example, the present disclosure provides a pellicle that includes a membrane and a frame supporting the membrane. The membrane may be formed from at least one of a transparent carbon-based film and a transparent silicon based film. The at least one of the transparent carbon-based film and the transparent silicon based film may further be coated with a protective shell. The frame may include at least one aperture to allow for a flow of air through a portion of the pellicle.
1. A method, comprising:
activating an extreme ultraviolet light source to pattern a resist layer on a substrate;
directing light emitted by the extreme ultraviolet light source onto a photomask;
catching falling particles on a pellicle positioned over the photomask, in order to keep the photomask clear of the falling particles while the light is directed onto the photomask, wherein the pellicle comprises:
a membrane, wherein the membrane comprises at least one selected from the group of a transparent carbon-based film and a transparent silicon: based film, wherein the at least one selected from the group of the transparent carbon-based film and the transparent silicon based film is coated with a protective shell that dissipates heat from the membrane; and
a frame supporting the membrane, wherein the frame includes at least one aperture to allow for a flow of air through a portion of the pellicle; and
collecting and directing a portion of the light that passes through the pellicle and the photomask onto the resist layer.
2. The method of claim 1 , wherein the transparent carbon-based film comprises a network of carbon nanotubes.
3. The method of claim 1 , wherein the transparent silicon-based film comprises a network of silicon nanowires.
4. A method, comprising:
providing an extreme ultraviolet light to a photomask through a pellicle on the photomask, wherein the pellicle comprises a transparent carbon-based film and a frame supporting the transparent carbon-based film, wherein the frame includes a vent structure to allow for a flow of air through a portion of the pellicle; and
directing a portion of the extreme ultraviolet light reflected from the photomask onto a resist layer on a substrate.
5. The method of claim 4 , wherein the transparent carbon-based film comprises a network of carbon nanotubes.
6. The method of claim 5 , wherein the network of carbon nanotubes has a structure density of between 0.2 and one.
7. The method of claim 4 , wherein the frame is formed from at least one of: silicon, silicon carbide, silicon nitride, glass, an aluminum alloy, a titanium alloy, Invar, and Kovar.
8. The method of claim 4 , wherein the transparent carbon-based film transmits more than eighty-two percent of the extreme ultraviolet light.
9. The method of claim 4 , wherein the vent structure includes one or more apertures formed on a sidewall of the frame.
10. The method of claim 9 , wherein the one or more apertures include a first aperture and a second aperture having a different shape than the first aperture.
11. The method of claim 10 , wherein the first aperture is slit-shaped aperture, and the second aperture is a circular aperture.
12. The method of claim 10 , wherein the one or more apertures further include a third aperture having a different shape than the first and second apertures.
13. The method of claim 12 , wherein the first aperture is slit-shaped aperture, the second aperture is a circular aperture, and the third aperture is a rectangular aperture.
14. The method of claim 13 , wherein the rectangular aperture and the circular aperture are on opposite sides of the slit-shaped aperture.
15. A method, comprising:
generating an extreme ultraviolet light to a photomask through a pellicle on the photomask, wherein the pellicle comprises a transparent carbon nanotube film, a protective shell coated on the transparent carbon nanotube film, and a frame supporting the transparent carbon nanotube film; and
directing a portion of the extreme ultraviolet light reflected from the photomask onto a resist layer on a substrate.
16. The method of claim 15 , wherein the protective shell comprises at least one of: ruthenium, molybdenum, zirconium, boron, niobium, molybdenum disilicide, silicon nitride, and silicon oxide.
17. The method of claim 15 , wherein the protective shell has a thickness between 0.1 and ten nanometers.
18. The method of claim 15 , wherein the pellicle further comprises a border positioned between the transparent carbon nanotube film and the frame, and the border is attached to the transparent carbon nanotube film by a pellicle membrane adhesive.
19. The method of claim 18 , wherein the pellicle membrane adhesive includes heat-dissipating fillers.
20. The method of claim 18 , wherein the pellicle membrane adhesive comprises at least one of: a thermoplastic elastomer type adhesive, a polystyrene type adhesive, an acrylic type adhesive, a silicon-based adhesive, and an epoxy type adhesive.