EUV photo masks and manufacturing method thereof
A reflective mask includes a substrate, a reflective multilayer disposed on the substrate, a capping layer disposed on the reflective multilayer, and an absorber layer disposed on the capping layer. The absorber layer includes a base material made of one or more of a Cr based material, an Ir based material, a Pt based material, or Co based material, and further contains one or more additional elements selected from the group consisting of Si, B, Ge, Al, As, Sb, Te, Se and Bi.
1. A reflective mask, comprising:
a substrate;
a reflective multilayer disposed on the substrate;
a capping layer disposed on the reflective multilayer; and
an absorber layer disposed on the capping layer,
wherein the absorber layer includes a base material layer made of one or more of a Cr-based material, an Ir-based material, a Pt-based material, or Co-based material, and the base material layer further contains one or more additional elements selected from the group consisting of Si, B, Ge, Al, As, Sb, Te, Se and Bi.
2. The reflective mask of claim 1 , wherein the one or more additional elements are not included in the base material layer.
3. The reflective mask of claim 1 , wherein a concentration of the one or more additional elements is in a range from 5 atomic % to 30 atomic %.
4. The reflective mask of claim 1 , wherein a concentration of the one or more additional elements in the absorber layer along vertical direction is not uniform.
5. The reflective mask of claim 1 , wherein the base material layer of the absorber layer is made of one selected from the group consisting of IrPt, IrAl, IrRu, IrB, IrN, IrSi, IrTi, PtAl, PtRu, PtB, PtSi, PtN, PtTi, CoO, CoB, CoBN, CoN and CoSi.
6. The reflective mask of claim 1 , wherein:
the absorber layer is patterned, and
the reflective mask further comprises a protective layer disposed on sidewalls of the patterned absorber layer.
7. The reflective mask of claim 6 , wherein the protective layer includes an oxide of the one or more additional elements.
8. A reflective mask, comprising:
a substrate;
a reflective multilayer disposed on the substrate;
a capping layer disposed on the reflective multilayer;
an intermediate layer disposed on the capping layer; and
an absorber layer disposed on the intermediate layer,
wherein the intermediate layer is a layer comprising one or more of Si, Ge, Al, As, Se and Bi.
9. The reflective mask of claim 8 , wherein the absorber layer includes one or more of a Cr-based material, an Ir-based material, a Pt-based material, or Co-based material.
10. The reflective mask of claim 8 , wherein a thickness of the intermediate layer is in a range from 1 nm to 10 nm.
11. The reflective mask of claim 8 , wherein:
the absorber layer is patterned, and
the reflective mask further comprises a protective layer disposed on sidewalls of the patterned absorber layer.
12. The reflective mask of claim 11 , wherein the protective layer includes a compound of Si, Ge, Al, As, Se and Bi.
13. The reflective mask of claim 11 , wherein the protective layer includes silicon oxide or boron oxide.
14. The reflective mask of claim 8 , wherein the absorber layer does not contain an element of the intermediate layer.
15. A method of manufacturing a reflective mask, the method comprising:
forming a photo resist layer over a mask blank, the mask blank including a substrate, a reflective multilayer on the substrate, a capping layer on the reflective multilayer, an absorber layer on the capping layer and a hard mask layer;
patterning the photo resist layer;
patterning the hard mask layer by using the patterned photo resist layer as a mask;
patterning the absorber layer by using the patterned hard mask layer as a mask; and
removing the hard mask layer, wherein:
during the patterning the absorber layer, a protective layer is formed on an etched sidewall of the absorber layer,
the protective layer suppresses lateral etching of the absorber layer, and
the absorber layer is patterned by plasma dry etching using a gas containing oxygen.
16. The method of claim 15 , wherein the absorber layer includes one or more of a Cr-based material, an Ir-based material, a Pt-based material, or Co-based material.
17. The method of claim 16 , wherein the protective layer includes a compound of one or more additional elements selected from the group consisting of Si, B, Ge, Al, As, Sb, Te, Se and Bi.
18. The method of claim 17 , wherein the one or more additional element are supplied form the absorber layer.
19. The method of claim 17 , wherein the one or more additional elements are supplied from an intermediate layer disposed between the capping layer and the absorber layer.
20. The method of claim 17 , wherein the protective layer includes an oxide of one or more additional elements selected from the group consisting of Si, Ge, Al, As, Se and Bi.