Mask blank and method of manufacturing a transfer mask
A mask blank having, on a light-transmissive substrate, a light-shielding film made of a material mainly containing chromium, and adapted to use a resist film for electron beam writing when forming a transfer pattern in the light-shielding film. In the mask blank, an etching mask film made of a material containing a nitride or oxynitride of silicon is formed on an upper surface of the light-shielding film and a conductive mask film made of a conductive material dry-etchable with a fluorine-based gas and a mixed gas of chlorine and oxygen is formed on an upper surface of the etching mask film.
1. A mask blank comprising:
a light-transmissive substrate;
a light-shielding film formed on an upper surface of a light-transmissive substrate and made of a material mainly containing chromium; and
a hard mask film consisting of a laminated film formed on said light-shielding film; wherein
said hard mask film comprises:
an etching mask film made of a material including silicon and dry-etchable with fluorine-based gas; and
a conductive mask film formed on an upper surface of said etching mask film and made of a conductive material which contains a main material different from silicon and is dry-etchable with a fluorine-based gas.
2. The mask blank according to claim 1 , wherein said conductive mask film is made of said conductive material containing one or more components among molybdenum, titanium, vanadium, niobium, and tungsten or containing the one or more components and nitrogen added thereto.
3. The mask blank according to claim 2 , wherein said conductive material is selected from a group consisting of MoN, TiN, VN, NbN, WN, Mo, Ti, V and Nb.
4. The mask blank according to claim 1 , wherein said conductive mask film made of a conductive material which is dry-etchable with not only a fluorine-based gas but also a chlorine gas.
5. The mask blank according to claim 1 , wherein said etching mask film serves as an antireflection film.
6. The mask blank according to claim 1 , wherein said conductive mask film has a thickness of 2 nm to 20 nm.
7. The mask blank according to claim 1 , wherein said laminated film of said etching mask film and said conductive mask film has a thickness of 7 nm to 32 nm.
8. The mask blank according to claim 1 , wherein said etching mask film made of a material including at least one of nitrogen and oxygen along with silicon.
9. The mask blank according to claim 1 , wherein said etching mask film made of a material selected from a group consisting of SiN, SiON, MoSi and MoSiON.
10. The mask blank according to claim 1 , wherein the mask blank further comprises a resist film for electron beam writing which is formed on an upper surface of said conductive mask film and has a thickness of 50 nm to 300 nm.
11. The mask blank according to claim 1 , wherein the mask blank further comprises a phase shift film between said light-transmissive substrate and said light-shielding film.
12. The mask blank according to claim 11 , wherein said conductive mask film is made of said conductive material containing one or more components among tantalum, molybdenum, titanium, vanadium, niobium, and tungsten or containing the one or more components and nitrogen added thereto.
13. The mask blank according to claim 12 , wherein said conductive material is selected from a group consisting of TaN, MoN, TiN, VN, NbN, WN, Ta, Mo, Ti, V and Nb.
14. The mask blank according to claim 11 , wherein said phase shift film is made of a material containing one of an oxide, an nitride and an oxynitride of molybdenum silicide.
15. The mask blank according to claim 11 , wherein said light-shielding film includes an antireflection function layer at a surface layer portion thereof.
16. The mask blank according to claim 15 , wherein said antireflection function layer made of a material selected from a group consisting of CrON, CrO, CrCO, and CrCON.