Reflective mask blank, reflective mask, and method for manufacturing semiconductor device
Provided is a reflective mask blank comprising a phase shift film having a small change in the phase difference and/or reflectance of the phase shift film even in a case where the film thickness of the phase shift film changes. A reflective mask blank comprises a multilayer reflective film and a phase shift film in this order on a main surface of a substrate. The phase shift film comprises a lower layer and an uppermost layer. The lower layer is located between the uppermost layer and the multilayer reflective film. The lower layer is formed of a material in which the total content of ruthenium and chromium is 90 atomic % or more, or a material in which the total content of ruthenium, chromium, and nitrogen is 90 atomic % or more. The uppermost layer is formed of a material in which the total content of ruthenium, chromium, and oxygen is 90 atomic % or more.
1. A reflective mask blank comprising a multilayer reflective film and a phase shift film in this order on a main surface of a substrate, wherein;
the phase shift film comprises a lower layer and an uppermost layer, the lower layer is located between the uppermost layer and the multilayer reflective film,
the lower layer comprises ruthenium and chromium, or ruthenium, chromium, and nitrogen,
the uppermost layer comprises ruthenium, chromium, and oxygen,
the lower layer is formed of a material in which a total content of ruthenium and chromium is 90 atomic % or more, or a material in which a total content of ruthenium, chromium, and nitrogen is 90 atomic % or more,
the uppermost layer is formed of a material in which a total content of ruthenium, chromium, and oxygen is 90 atomic % or more, and
wherein an element having a largest content in the lower layer is ruthenium.
2. The reflective mask blank according to claim 1 , wherein an element having a largest content in the uppermost layer is oxygen.
3. The reflective mask blank according to claim 1 , wherein a refractive index of the uppermost layer with respect to light having a wavelength of 13.5 nm is larger than a refractive index of the lower layer with respect to light having a wavelength of 13.5 nm.
4. The reflective mask blank according to claim 3 , wherein the refractive index of the uppermost layer with respect to light having a wavelength of 13.5 nm is 0.94 or less.
5. The reflective mask blank according to claim 1 , wherein a refractive index of the uppermost layer with respect to light having a wavelength of 193 nm is larger than a refractive index of the lower layer with respect to light having a wavelength of 193 nm.
6. The reflective mask blank according to claim 5 , wherein the refractive index of the uppermost layer with respect to light having a wavelength of 193 nm is 5.0 or less.
7. The reflective mask blank according to claim 5 , wherein an extinction coefficient of the uppermost layer with respect to light having a wavelength of 193 nm is 3.2 or less.
8. The reflective mask blank according to claim 1 , comprising a protective film between the multilayer reflective film and the phase shift film.
9. A reflective mask comprising a multilayer reflective film and a phase shift film having a transfer pattern formed thereon in this order on a main surface of a substrate, wherein:
the phase shift film comprises a lower layer and an uppermost layer, the lower layer is located between the uppermost layer and the multilayer reflective film,
the lower layer comprises ruthenium and chromium, or ruthenium, chromium, and nitrogen,
the uppermost layer comprises ruthenium, chromium, and oxygen,
the lower layer is formed of a material in which a total content of ruthenium and chromium is 90 atomic % or more, or a material in which a total content of ruthenium, chromium, and nitrogen is 90 atomic % or more,
the uppermost layer is formed of a material in which a total content of ruthenium, chromium, and oxygen is 90 atomic % or more, and
wherein an element having a largest content in the lower layer is ruthenium.
10. The reflective mask according to claim 9 , wherein an element having a largest content in the uppermost layer is oxygen.
11. The reflective mask according to claim 9 , wherein a refractive index of the uppermost layer with respect to light having a wavelength of 13.5 nm is larger than a refractive index of the lower layer with respect to light having a wavelength of 13.5 nm.
12. The reflective mask according to claim 11 , wherein the refractive index of the uppermost layer with respect to light having a wavelength of 13.5 nm is 0.94 or less.
13. The reflective mask according to claim 9 , wherein a refractive index of the uppermost layer with respect to light having a wavelength of 193 nm is larger than a refractive index of the lower layer with respect to light having a wavelength of 193 nm.
14. The reflective mask according to claim 13 , wherein the refractive index of the uppermost layer with respect to light having a wavelength of 193 nm is 5.0 or less.
15. The reflective mask according to claim 13 , wherein an extinction coefficient of the uppermost layer with respect to light having a wavelength of 193 nm is 3.2 or less.
16. The reflective mask according to claim 9 , comprising a protective film between the multilayer reflective film and the phase shift film.
17. A reflective mask blank comprising a multilayer reflective film and a phase shift film in this order on a main surface of a substrate, wherein:
the phase shift film comprises a lower layer and an uppermost layer, the lower layer is located between the uppermost layer and the multilayer reflective film,
the lower layer comprises ruthenium and chromium or ruthenium, chromium, and nitrogen,
the uppermost layer comprises ruthenium, chromium, and oxygen,
the lower layer is formed of a material in which a total content of ruthenium and chromium is 90 atomic % or more, or a material in which a total content of ruthenium, chromium, and nitrogen is 90 atomic % or more,
the uppermost layer is formed of a material in which a total content of ruthenium, chromium, and oxygen is 90 atomic % or more, and
a ratio obtained by dividing a content in atomic % of chromium by a total content in atomic % of ruthenium and chromium in the uppermost layer is larger than a ratio obtained by dividing a content in atomic % of chromium by a total content in atomic % of ruthenium and chromium in the lower layer.
18. The reflective mask blank according to claim 17 , wherein a refractive index of the uppermost layer with respect to light having a wavelength of 13.5 nm is larger than a refractive index of the lower layer with respect to light having a wavelength of 13.5 nm.
19. A reflective mask comprising a multilayer reflective film and a phase shift film having a transfer pattern formed thereon in this order on a main surface of a substrate, wherein:
the phase shift film comprises a lower layer and an uppermost layer, the lower layer is located between the uppermost layer and the multilayer reflective film,
the lower layer comprises ruthenium and chromium or ruthenium, chromium, and nitrogen,
the uppermost layer comprises ruthenium, chromium, and oxygen,
the lower layer is formed of a material in which a total content of ruthenium and chromium is 90 atomic % or more, or a material in which a total content of ruthenium, chromium, and nitrogen is 90 atomic % or more,
the uppermost layer is formed of a material in which a total content of ruthenium, chromium, and oxygen is 90 atomic % or more, and
a ratio obtained by dividing a content in atomic % of chromium by a total content in atomic % of ruthenium and chromium in the uppermost layer is larger than a ratio obtained by dividing a content in atomic % of chromium by a total content in atomic % of ruthenium and chromium in the lower layer.
20. The reflective mask according to claim 19 , wherein a refractive index of the uppermost layer with respect to light having a wavelength of 13.5 nm is larger than a refractive index of the lower layer with respect to light having a wavelength of 13.5 nm.