A mask blank includes a glass substrate including a first main surface and a second main surface, an absorbing film formed above the first main surface, and a conductive film formed on the second main surface. A reflective film is provided between the absorbing film and the glass substrate. In a surface of the conductive film on an opposite side to the glass substrate, when a surface shape of a square central area having a length of 142 mm and a width of 142 mm excluding a four-sided frame-shaped peripheral area thereof is expressed by the specific formula, flatness of a component obtained by summing all a kl P k (x)P l (y) with the sum of k and l being 3 or more and 25 or less is 20 nm or less.
1. A mask blank comprising:
a glass substrate including a first main surface and a second main surface facing the first main surface;
a circuit-forming film formed above the first main surface, the circuit-forming film being a film where a circuit pattern is to be formed and comprising an absorbing film that absorbs light;
a reflective film that reflects the light, provided between the absorbing film and the glass substrate; and
a conductive film formed on the second main surface; wherein:
the conductive film has a chucking surface on an opposite side to the glass substrate;
the chucking surface has a square central area having a length of having a length of 142 mm and a width of 142 mm at the center of the chucking surface; and
when a surface shape z(x, y) of the square central area of the chucking surface is expressed by the following formula, a flatness of the square central area of the chucking surface obtained by summing all a kl P k (x)P l (y) with the sum of k and l in the following formula being 3 or more and 25 or less is 20 nm or less:
{
z
(
x
,
y
)
=
∑
k
=
0
N
1
∑
l
=
0
N
2
a
kl
P
k
(
x
)
P
l
(
y
)
P
k
(
x
)
=
1
2
k
k
!
d
k
dx
k
[
(
x
2
-
1
)
k
]
P
l
(
y
)
=
1
2
l
l
!
d
l
dy
l
[
(
y
2
-
1
)
l
]
wherein x indicates a coordinate in a transverse direction, y indicates a coordinate in a longitudinal direction, and z indicates a coordinate in a height direction, the transverse direction, the longitudinal direction and the height direction being perpendicular to each other, and each of k and l is a natural number of 0 or more and 25 or less, the sum of k and l is 3 or more and 25 or less, and each of N1 and N2 is 25.
2. The mask blank according to claim 1 , wherein:
the circuit-forming film has a circuit-forming surface on an opposite side to the glass substrate;
the circuit-forming surface has a square central area having a length of having a length of 142 mm and a width of 142 mm at the center of the circuit-forming surface;
when a surface shape z(x, y) of the square central area of the circuit-forming surface is expressed by the following formula, a flatness of the square central area of the circuit-forming surface obtained by summing all a kl P k (x)P l (y) with the sum of k and l in the following formula being 3 or more and 25 or less is 20 nm or less:
{
z
(
x
,
y
)
=
∑
k
=
0
N
1
∑
l
=
0
N
2
a
kl
P
k
(
x
)
P
l
(
y
)
P
k
(
x
)
=
1
2
k
k
!
d
k
dx
k
[
(
x
2
-
1
)
k
]
P
l
(
y
)
=
1
2
l
l
!
d
l
dy
l
[
(
y
2
-
1
)
l
]
wherein x indicates a coordinate in a transverse direction, y indicates a coordinate in a longitudinal direction, and z indicates a coordinate in a height direction, the transverse direction, the longitudinal direction and the height direction being perpendicular to each other, and each of k and l is a natural number of 0 or more and 25 or less, the sum of k and l is 3 or more and 25 or less, and each of N1 and N2 is 25.
3. The mask blank according to claim 2 , wherein the circuit-forming film further comprises a low reflective film, provided such that the absorbing film is positioned between the low reflective film and the reflective film.
4. The mask blank according to claim 2 , further comprising a protective film provided between the absorbing film and the reflective film.
5. The mask blank according to claim 2 , wherein the flatness of the square central area of the chucking surface is 18 nm or less.
6. The mask blank according to claim 5 , wherein the flatness of the square central area of the circuit-forming surface is 18 nm or less.
7. The mask blank according to claim 2 , wherein the flatness of the square central area of the chucking surface is 16 nm or less.
8. The mask blank according to claim 7 , wherein the flatness of the square central area of the circuit-forming surface is 16 nm or less.
9. The mask blank according to claim 1 , wherein the circuit-forming film further comprises a low reflective film, provided such that the absorbing film is positioned between the low reflective film and the reflective film.
10. The mask blank according to claim 1 , further comprising a protective film provided between the absorbing film and the reflective film.
11. The mask blank according to claim 1 , wherein the flatness of the square central area of the chucking surface is 18 nm or less.
12. The mask blank according to claim 1 , wherein the flatness of the square central area of the chucking surface is 16 nm or less.