Reflective mask blank for EUV lithography, and reflective layer-coated substrate for EUV lithography

1. A reflective layer-coated substrate for EUV lithography (EUVL), comprising a substrate, and a reflective layer for reflecting EUV light, formed on the substrate, wherein

the reflective layer comprises a second multilayer reflective film having a Mo layer and a Si layer alternately stacked plural times on the substrate, an adjustment layer stacked on the second multilayer reflective film, and a first multilayer reflective film having a Mo layer and a Si layer alternately stacked plural times on the adjustment layer;

in the first multilayer reflective film, from 20 to 36 sets are stacked in such a relation that the first cycle length d 1 being the total thickness of one set of adjacent Mo layer and Si layer is 6.8 nm≦d 1 ≦7.2 nm;

in the adjustment layer, a Mo layer and a Si layer are alternately stacked in at least one set, the total thickness d 3 of adjacent Mo layer and Si layer satisfies d 3 ≦0.8d 1 or 1.2d 1 ≦d 3 , and the thickness L of the entire adjustment layer is (0.3+i)d 1 ≦L≦(0.7+i)d 1 , wherein i is an integer greater than or equal to 0;

in the second multilayer reflective film, from 3 to 31 sets are stacked in such a relation that the second cycle length d 2 being the total thickness of one set of adjacent Mo layer and Si layer is 0.9d 1 ≦d 2 ≦1.1d 1 ;

the ratio of the thickness of a Mo layer in the first multilayer reflective film to the first cycle length d 1 is from 0.25 to 0.55;

the ratio of the thickness of a Mo layer in the second multilayer reflective film to the second cycle length d 2 is from 0.25 to 0.55; and

the total thickness of the reflective layer is at most 600 nm.

2. The reflective layer-equipped substrate for EUVL according to claim 1 , wherein the total thickness of the reflective layer is at most 400 nm.

3. The reflective layer-equipped substrate for EUVL according to claim 1 , wherein the first cycle length d 1 and the second cycle length d 2 are substantially equal.

4. The reflective layer-equipped substrate for EUVL according to claim 1 , wherein the ratio of the thickness of a Mo layer in the adjustment layer to the third cycle length d 3 is from 0.3 to 0.7.

5. A reflective mask blank for EUV lithography (EUVL), comprising a substrate, a reflective layer for reflecting EUV light, formed on the substrate, and an absorber layer for absorbing EUV light, formed on the reflective layer, wherein

the reflective layer comprises a second multilayer reflective film having a second low refractive index layer and a second high refractive index layer alternately stacked plural times on the substrate, an adjustment layer stacked on the second multilayer reflective film, and a first multilayer reflective film having a Mo layer and a Si layer alternately stacked plural times on the adjustment layer;

in the first multilayer reflective film, from 20 to 36 sets are stacked in such a relation that the first cycle length d 1 being the total thickness of one set of adjacent Mo layer and Si layer is 6.8 nm≦d 1 ≦7.2 nm;

in the adjustment layer, a Mo layer and a Si layer are alternately stacked in at least one set, the total thickness d 3 of adjacent Mo layer and Si layer satisfies d 3 ≦0.8d 1 or 1.2d 1 ≦d 3 , and the thickness L of the entire adjustment layer is (0.3+i)d 1 ≦L≦(0.7+i)d 1 , wherein i is an integer greater than or equal to 0;

in the second multilayer reflective film, from 3 to 31 sets are stacked in such a relation that the second cycle length d 2 being the total thickness of one set of adjacent Mo layer and Si layer is 0.9d 1 ≦d 2 ≦1.1d 1 ;

the ratio of the thickness of a Mo layer in the first multilayer reflective film to the first cycle length d 1 is from 0.25 to 0.55;

the ratio of the thickness of a Mo layer in the second multilayer reflective film to the second cycle length d 2 is from 0.25 to 0.55; and

the total thickness of the reflective layer is at most 600 nm.

6. The reflective mask blank for EUVL according to claim 5 , wherein the total thickness of the reflective layer is at most 400 nm.

7. The reflective mask blank for EUVL according to claim 5 , wherein the first cycle length d 1 and the second cycle length d 2 are substantially equal.

8. The reflective mask blank for EUVL according to claim 5 , wherein the ratio of the thickness of a Mo layer in the adjustment layer to the third cycle length d 3 is from 0.3 to 0.7.

9. The reflective mask blank for EUVL according to claim 5 , which has a protective layer for the reflective layer, between the reflective layer and the absorber layer.