Fly eye lens and proximity exposure machine optical system
An embodiment of the present invention provides a fly eye lens which is applied to a proximity exposure machine optical system. The fly lens includes a first lens assembly and a second lens assembly, wherein the first lens assembly includes a plurality of lenses which form a first lens face, and the second lens assembly includes a plurality of lenses which form a second lens face. The first lens face is used to split an incident broad light beam into narrow light beams and then refract the narrow light beams onto the second lens face, and the second lens face is used to dispersively refract the received narrow light beams onto a concave mirror in the optical system. A lens closer to a center of the second lens face has a higher transmittivity, and a lens farther from the center of the second lens face has a lower transmittivity. According to the embodiment of the present invention, since different lenses on the second lens face have different transmittivities, the illuminances of light radiated to different regions of a mask plate through the fly eye lens are different, and thus the uniformity of the critical dimensions of the exposed patterns can be improved to a certain extent.
1. A fly eye lens applied to a proximity exposure machine optical system, comprising:
a first lens assembly which includes a plurality of lenses forming a first lens face; and
a second lens assembly which includes a plurality of lenses forming a second lens face,
wherein the first lens face is used to split an incident broad light beam into narrow light beams and then refract the narrow light beams onto the second lens face, and the second lens face is used to dispersively refract the received narrow light beams onto a concave mirror in the optical system,
among the plurality of lenses in the second lens assembly, a lens which is closer to a center of the second lens face has a higher transmittivity than a lens which is farther from the center of the second lens face.
2. The fly eye lens according to claim 1 , wherein transmittivities of the lenses in the second lens assembly are between 60% and 100%.
3. The fly eye lens according to claim 2 , wherein
a lens closest to the center of the second lens face in the second lens assembly has a highest transmittivity among the plurality of lenses forming the second lens face.
4. The fly eye lens according to claim 3 , wherein
a distance from each lens in the second lens assembly to the center of the second lens face is defined as a distance from a center of each lens in the second lens assembly to the center of the second lens face.
5. The fly eye lens according to claim 2 , wherein
a distance from each lens in the second lens assembly to the center of the second lens face is defined as a distance from a center of each lens in the second lens assembly to the center of the second lens face.
6. The fly eye lens according to claim 1 , wherein
the transmittivity of each lens in the second lens assembly can be obtained by the following formulae:
∑
i
,
j
T
ij
×
P
Eij
(
x
,
y
)
=
P
0
-
Δ
P
Δ
P
=
Δ
T
=
1
t
×
K
1
K
2
×
H
×
[
1
-
(
l
L
)
n
]
wherein T ij denotes a transmittivity of each lens in the second lens assembly,
∑
i
,
j
T
ij
×
P
Eij
(
x
,
y
)
denotes illuminance on the concave mirror onto which the second lens face refracts the received light beams,
P 0 denotes a known illuminance at a center of the concave mirror,
ΔP denotes a difference of the illuminance at the selected point other than the center and the illuminance at the center, on the concave mirror to which the second lens face refracts the received light beams,
ΔT denotes a difference of an illuminance at the selected point other than a center and an illuminance at the center, on a mask plate, to which the second lens face refracts the received light beams, in the optical system,
t, n, K 1 and K 2 are constants, 0<K 1 <1, 0<K 2 <1, and n>1,
l denotes a distance between the selected point other than the center on the mask plate and the center of the mask plate,
L denotes a distance between the center of the mask plate and an intersection, which is a point at which a straight line formed by connecting the selected point on the mask plate and the center of the mask plate intersects with an edge of the mask plate, on the edge of the mask plate, and
H denotes a maximum variation of amount of an exposure distance at the center of the mask plate.
7. The fly eye lens according to claim 6 , wherein
a distance from each lens in the second lens assembly to the center of the second lens face is defined as a distance from a center of each lens in the second lens assembly to the center of the second lens face.
8. The fly eye lens according to claim 1 , wherein
the transmittivities of the lenses in the second lens assembly are determined according to a bending degree of a mask plate caused by the proximity exposure machine optical system.
9. The fly eye lens according to claim 8 , wherein
a distance from each lens in the second lens assembly to the center of the second lens face is defined as a distance from a center of each lens in the second lens assembly to the center of the second lens face.
10. The fly eye lens according to claim 1 , wherein
a distance from each lens in the second lens assembly to the center of the second lens face is defined as a distance from a center of each lens in the second lens assembly to the center of the second lens face.
11. A proximity exposure machine optical system comprising:
a lamp;
at least one mirror; and
a fly eye lens, wherein the fly eye lens includes:
a first lens assembly which includes a plurality of lenses forming a first lens face; and
a second lens assembly which includes a plurality of lenses forming a second lens face,
the first lens face is used to split an incident broad light beam into narrow light beams and then refract the narrow light beams onto the second lens face, and the second lens face is used to dispersively refract the received narrow light beams onto a concave mirror in the optical system,
among the plurality of lenses in the second lens assembly, a lens which is closer to a center of the second lens face has a higher transmittivity than a lens which is farther from the center of the second lens face.
12. The proximity exposure machine optical system according to claim 11 , wherein transmittivities of the lenses in the second lens assembly are between 60% and 100%.
13. The proximity exposure machine optical system according to claim 12 , wherein
a lens closest to the center of the second lens face in the second lens assembly has a highest transmittivity among the plurality of lenses forming the second lens face.
14. The proximity exposure machine optical system according to claim 13 , wherein
a distance from each lens in the second lens assembly to the center of the second lens face is defined as a distance from a center of each lens in the second lens assembly to the center of the second lens face.
15. The proximity exposure machine optical system according to claim 12 , wherein
a distance from each lens in the second lens assembly to the center of the second lens face is defined as a distance from a center of each lens in the second lens assembly to the center of the second lens face.
16. The proximity exposure machine optical system according to claim 11 , wherein
the transmittivity of each lens in the second lens assembly can be obtained by the following formulae:
∑
i
,
j
T
ij
×
P
Eij
(
x
,
y
)
=
P
0
-
Δ
P
Δ
P
=
Δ
T
=
1
t
×
K
1
K
2
×
H
×
[
1
-
(
l
L
)
n
]
wherein T ij denotes a transmittivity of each lens in the second lens assembly,
∑
i
,
j
T
ij
×
P
Eij
(
x
,
y
)
denotes illuminance on the concave mirror onto which the second lens face refracts the received light beams,
P 0 denotes a known illuminance at a center of the concave mirror,
ΔP denotes a difference of the illuminance at the selected point other than the center and the illuminance at the center, on the concave mirror to which the second lens face refracts the received light beams,
ΔT denotes a difference of an illuminance at the selected point other than a center and an illuminance at the center, on a mask plate, to which the second lens face refracts the received light beams, in the optical system,
t, n, K 1 and K 2 are constants, 0<K 1 <1, 0<K 2 <1, and n>1,
l denotes a distance between the selected point other than the center on the mask plate and the center of the mask plate,
L denotes a distance between the center of the mask plate and an intersection, which is a point at which a straight line formed by connecting the selected point on the mask plate and the center of the mask plate intersects with an edge of the mask plate, on the edge of the mask plate, and
H denotes a maximum variation of amount of an exposure distance at the center of the mask plate.
17. The proximity exposure machine optical system according to claim 16 , wherein
a distance from each lens in the second lens assembly to the center of the second lens face is defined as a distance from a center of each lens in the second lens assembly to the center of the second lens face.
18. The proximity exposure machine optical system according to claim 11 , wherein
the transmittivities of the lenses in the second lens assembly are determined according to a bending degree of a mask plate caused by the proximity exposure machine optical system.
19. The proximity exposure machine optical system according to claim 18 , wherein
a distance from each lens in the second lens assembly to the center of the second lens face is defined as a distance from a center of each lens in the second lens assembly to the center of the second lens face.
20. The proximity exposure machine optical system according to claim 11 , wherein
a distance from each lens in the second lens assembly to the center of the second lens face is defined as a distance from a center of each lens in the second lens assembly to the center of the second lens face.