Reflective mask blank, reflective mask, and method for manufacturing semiconductor device
To provide a reflective mask blank which may inhibit a variation in reflectance with respect to EUV light due to counter diffusion between a protective film and a material of an adjacent phase-shift film pattern caused by thermal diffusion even if the power of an exposure light source of an EUV exposure machine becomes high; a reflective mask manufactured therefrom; and a method for manufacturing a semiconductor device. The reflective mask blank comprises a multilayer reflective film 13 , protective film 14 , and phase-shift film 16 for shifting a phase of the EUV light, which are formed in said order on a substrate 12 . The protective film 14 is made of a material containing ruthenium as a main component, the phase-shift film 16 has a tantalum-based material layer comprising tantalum, and an anti-diffusion layer 15 comprising ruthenium and oxygen is formed on a surface of the protective film 14 , or as a part of the protective film 14 on a side adjacent to the phase-shift layer 16 , so as to inhibit counter diffusion in relation to the phase-shift film 16 , thereby inhibiting the thermal diffusion between the protective film 14 and the material of the phase-shift film pattern.
1. A reflective mask blank comprising:
a substrate, and
a multilayer reflective film, a protective film, and a phase-shift film for shifting a phase of EUV light, which are formed in said order on the substrate,
wherein the protective film is made of a material containing ruthenium as a main component,
wherein the phase-shift film has a tantalum-based material layer comprising tantalum, and
wherein an anti-diffusion layer comprising ruthenium and oxygen is formed on a surface of the protective film, or as a part of the protective film on a side adjacent to the phase-shift film, so as to inhibit counter diffusion in relation to the phase-shift film.
2. The reflective mask blank according to claim 1 , wherein the tantalum-based material layer is adjacent to the anti-diffusion layer.
3. The reflective mask blank according to claim 1 , wherein a thickness of the anti-diffusion layer is not less than 0.2 nm and not more than 1.5 nm.
4. The reflective mask blank according to claim 1 , wherein the phase-shift film is formed in a laminated structure, and has a chromium-based material layer as an outermost surface layer.
5. The reflective mask blank according to claim 4 , wherein the chromium-based material layer comprises carbon.
6. The reflective mask blank according to claim 1 , wherein the phase-shift film is formed in a laminated structure, and has a ruthenium-based material layer as an outermost surface layer.
7. The reflective mask blank according to claim 1 , wherein the phase-shift film is formed by a sputtering method, and has a laminated structure formed continuously without exposure to the atmosphere from the beginning to the end of film formation.
8. The reflective mask blank according to claim 1 , wherein an etching mask film is formed on the phase-shift film.
9. The reflective mask blank according to claim 1 , wherein an uppermost layer of the multilayer reflective film is silicon (Si), and a silicon oxide layer comprising silicon and oxygen is provided between the uppermost layer and the protective film.
10. A reflective mask manufactured from the reflective mask blank according to claim 1 .
11. A method for manufacturing a semiconductor device, comprising the step of:
setting the reflective mask according to claim 10 on an exposure apparatus having an exposure light source for emitting EUV light, so as to transfer a transfer pattern onto a resist film formed on a transfer target substrate.
12. The method for manufacturing a semiconductor device according to claim 11 , wherein the power (electric power) of the exposure light source is 80 W or more.