Immersion lithographic system
An immersion lithographic system may include a wafer stage configured to support a wafer, a projection optical system on the wafer stage and configured to irradiate light toward the wafer, a liquid supply unit configured to supply a liquid between the wafer stage and the projection optical system to form an immersion lens through which the light is transmitted, and a vapor supply unit configured to supply vapors to the immersion lens. The immersion lens and the vapor supply unit may be aligned in a vertical direction.
1 . An immersion lithographic system comprising:
a wafer stage;
a projection optical system on the wafer stage and configured to irradiate light toward the wafer stage;
a liquid supply unit configured to supply a liquid between the wafer stage and the projection optical system to form an immersion-fluid lens through which the light is transmitted; and
a vapor supply unit configured to supply vapors to the immersion-fluid lens,
wherein the immersion-fluid lens comprises a meniscus forming a contact angle of 90° or less with a wafer on the wafer stage,
wherein the vapor supply unit includes a vapor supply line configured to supply the vapors to the immersion-fluid lens,
wherein at least an edge portion of the meniscus of the immersion-fluid lens and the vapor supply line of the vapor supply unit are aligned in a vertical direction such that the vapor supply line is over the edge portion of the meniscus in the vertical direction, and
wherein a thickness of the edge portion of the meniscus is less than a thickness of an inner portion of the immersion-fluid lens, and the inner portion of the immersion-fluid lens is under and aligned in the vertical direction with a liquid supply line of the liquid supply unit.
2 . The immersion lithographic system of claim 1 , wherein the vapor supply unit is configured to increase the contact angle of the meniscus with the wafer by supplying the vapors to the immersion-fluid lens.
3 . The immersion lithographic system of claim 1 , wherein the vapor supply unit is configured to reduce a length of the meniscus by supplying the vapors to the immersion-fluid lens.
4 . The immersion lithographic system of claim 1 , wherein the vapor supply unit comprises:
a vapor recovery line configured to recover the vapors supplied to the immersion-fluid lens.
5 . The immersion lithographic system of claim 1 , wherein,
in a plan view, the vapor supply unit is arranged outside the liquid supply unit.
6 . The immersion lithographic system of claim 1 , wherein the vapors comprise at least one of methyl acetate and methyl ethyl ketone.
7 . An immersion lithographic system comprising:
a wafer stage;
a projection optical system on the wafer stage and configured to irradiate light toward the wafer stage;
a liquid supply unit configured to supply a liquid between the wafer stage and the projection optical system to form an immersion-fluid lens through which the light is transmitted, wherein the immersion-fluid lens comprises a meniscus forming a contact angle of 90° or less with a wafer on the wafer stage,
the liquid supply unit including at least one liquid supply line and a plurality of liquid recovery lines; and
a vapor supply unit configured to supply vapors between the wafer stage and the projection optical system, the vapor supply unit including a plurality of vapor supply lines and a plurality of vapor recovery lines, wherein
the plurality of vapor supply lines are configured to supply the vapors to the immersion-fluid lens,
the projection optical system includes a head portion disposed at a lower portion of the projection optical system,
the at least one liquid supply line, the plurality of liquid recovery lines, the plurality of vapor supply lines, and the plurality of vapor recovery lines are arranged in the head portion, and
the vapors supplied from the vapor supply unit reduce a capillary number of the immersion-fluid lens,
wherein at least an edge portion of the meniscus of the immersion-fluid lens and the plurality of vapor supply lines of the vapor supply unit are aligned in a vertical direction such that the plurality of vapor supply lines are over the edge portion of the meniscus in the vertical direction,
wherein a thickness of the edge portion of the meniscus is less than a thickness of an inner portion of the immersion-fluid lens, and
the inner portion of the immersion-fluid lens is under and aligned in the vertical direction with the at least one liquid supply line.
8 . The immersion lithographic system of claim 7 , wherein the at least one liquid supply line, the plurality of liquid recovery lines, the plurality of vapor supply lines, and the plurality of vapor recovery lines each penetrate the head portion in the vertical direction.
9 . The immersion lithographic system of claim 7 , wherein, in a plan view, the plurality of vapor supply lines are surrounded by the plurality of vapor recovery lines.
10 . The immersion lithographic system of claim 7 , wherein a distance from a center of the head portion to the liquid supply unit and a distance from the center of the head portion to the vapor supply unit satisfy Equation 1:
L
=
R
×
1
sin
∅
[
Equation
1
]
herein, in Equation 1,
L is a distance from the center of the head portion to the vapor supply unit,
R is a distance from the center of the head portion to the liquid supply unit, and
Ø is an angle between the meniscus and the wafer.
11 . The immersion lithographic system of claim 7 , wherein a distance from a center of the head portion to the vapor supply unit is 1 time to √2 times a distance from the center of the head portion to the liquid supply unit.
12 . The immersion lithographic system of claim 7 , wherein the plurality of liquid recovery lines, the plurality of vapor supply lines, and the plurality of vapor recovery lines are arranged on circumferences of a plurality of circles centered on a center of the head portion.
13 . The immersion lithographic system of claim 7 , wherein the vapors have a solubility of 10% to 20% in the liquid included in the immersion-fluid lens.
14 . The immersion lithographic system of claim 7 , wherein
the liquid comprises water, and
the vapors comprise at least one of acetone, methyl acetate, and methyl ethyl ketone.
15 . An immersion lithographic system comprising:
a light source configured to generate and irradiate light;
an illumination optical system configured to irradiate the light to a reticle;
a wafer stage;
a projection optical system facing the wafer stage and configured to irradiate, toward the wafer stage, the light that has passed through the reticle;
a liquid supply unit configured to supply a liquid between the wafer stage and the projection optical system to form an immersion-fluid lens through which the light is transmitted, and comprising at least one liquid supply line and a plurality of liquid recovery lines, wherein the immersion-fluid lens comprises a meniscus forming a contact angle of 90° or less with a wafer on the wafer stage; and
a vapor supply unit configured to supply vapors between the wafer stage and the projection optical system, the vapor supply unit including a plurality of vapor supply lines and a plurality of vapor recovery lines, wherein
the projection optical system includes a head portion at a lower portion of the projection optical system,
the at least one liquid supply line, the plurality of liquid recovery lines, the plurality of vapor supply lines, and the plurality of vapor recovery lines are in the head portion,
the vapors supplied from the vapor supply unit reduce a capillary number of the immersion-fluid lens,
at least an edge portion of a meniscus of the immersion-fluid lens and the plurality of vapor supply lines of the vapor supply unit are aligned in a vertical direction such that the plurality of vapor supply lines are over the edge portion of the meniscus in the vertical direction,
a thickness of the edge portion of the meniscus is less than a thickness of an inner portion of the immersion-fluid lens, and
the inner portion of the immersion-fluid lens is under and aligned in the vertical direction with the at least one liquid supply line of the liquid supply unit.
16 . The immersion lithographic system of claim 15 , wherein a distance from a center of the head portion to the vapor supply unit is 1 time to √2 times a radius of a space defined by the liquid supply unit.
17 . The immersion lithographic system of claim 15 , further comprising:
a vapor flow rate controller configured to control a flow rate of the vapors supplied to the meniscus.
18 . The immersion lithographic system of claim 15 , wherein the contact angle of the immersion-fluid lens is 30° or more.
19 . The immersion lithographic system of claim 15 , wherein a height of the immersion-fluid lens is 50 micrometers to 500 micrometers.