Projection optical system and exposure apparatus
An projection optical system for an i-line projection exposure apparatus includes positive, negative, positive, negative and positive lens units which include a lens having an Abbe number equal to or smaller than 62. 0.125≦NAO, −0.251<β<−0.249, 80 mm≦|OB 1 max|, 20 mm≦|OB 2 max|, |Dt/(NAO·|OB 1 max|)|≦62.0, Dt/Td≦0.645, 0.072≦|OB 1 max|/Td| are met, where NAO is a numerical aperture on the object plane, β is an imaging magnification, Td is a distance on an optical axis from the object plane to the image plane, Dt is a sum of thicknesses of the glass materials on the optical axis in the projection optical system, OB 1 max is a maximum object height on the object plane, and OB 2 max is a maximum image height on the image plane.
1. A projection optical system used for an exposure apparatus that uses an i-line as a light source, and configured to project a pattern of an original that is placed on an object plane onto a substrate that is placed on an image plane, the projection optical system comprising a plurality of lenses made of a plurality of types of different glass materials which include a lens having an Abbe number equal to or smaller than 62,
wherein the plurality of lenses include, in order from the object plane along an optical path, a first lens unit having a positive power, a second lens unit having a negative power, a third lens unit having a positive power, a fourth lens unit having a negative power, and a fifth lens unit having a positive power,
wherein the projection optical system satisfies following equations, where NAO is a numerical aperture of the projection optical system on the object plane, β is an imaging magnification of the projection optical system, Td is a distance on an optical axis from the object plane to the image plane, Dt is a sum of thicknesses of the glass materials on the optical axis in the projection optical system, OB 1 max is a maximum object height on the object plane, and OB 2 max is a maximum image height on the image plane:
0.125≦NAO
−0.251<β<−0.249
80 mm≦| OB 1max|
20 mm≦| OB 2max|
| Dt /( NAO·|OB 1max|)|≦62.0
Dt/Td≦ 0.645
0.072≦| OB 1max|/ Td 1.
2. The projection optical system according to claim 1 , wherein following equations are met, where S 1 is an air conversion distance from the object plane to a surface on an object plane side of one of the lenses that are made of a glass material that is not quartz and has a refractive index of 1.48 or higher, which is closest to the object plane, and S 2 is an air conversion distance from the image plane to a surface on an image plane side of one of the lenses that are made of a glass material that is not quartz and has a refractive index of 1.48 or higher, which is closest to the image plane:
102 mm≦S1
80 mm≦S2.
3. The projection optical system according to claim 1 , wherein following equations are met, where d 1 is a sum of thicknesses of the glass materials of the first lens unit on the optical axis, and d 2 is a sum of thicknesses of the glass materials of the second lens unit on the optical axis:
( d 1 +d 2)/ Td≦ 0.165
( d 1 +d 2)/ Dt≦ 0.250.
4. The projection optical system according to claim 1 , wherein following equations are met, where Kt is the number of lenses made of the glass material that has a refractive index equal to or higher than 1.57 or the Abbe number equal to or smaller than 62, and Gt is a sum of thicknesses on the optical axis of the glass materials each of which has a refractive index equal to or higher than 1.57 or an Abbe number equal to or smaller than 62:
Kt≦5
Gt/Td≦ 0.050.
5. The projection optical system according to claim 1 , wherein following equations are met, where P 1 is a distance along the optical axis between a pupil and a surface on an image plane side of one of the lenses which is placed on an object plane side of the pupil and closest to the pupil, and P 2 is a distance along the optical axis between the pupil and a surface on the image plane side of one of the lenses which is placed on the image plane side of the pupil and closest to the pupil:
0.010 ≦|P 1 /Td|
0.014≦| P 2 /Td|.
6. The projection optical system according to claim 1 , wherein one of the lenses that is closest to the pupil and arranged on an object plane side or an image plane side of the pupil is made of quartz.
7. The projection optical system according to claim 1 , wherein the second lens unit includes at least two quartz lenses.
8. An exposure apparatus that uses an i-line as a light source, the exposure apparatus comprising a projection optical system configured to project a pattern of an original that is placed on an object plane onto a substrate that is placed on an image plane,
wherein the projection optical system includes a plurality of lenses made of a plurality of types of different glass materials which include a lens having an Abbe number equal to or smaller than 62,
wherein the plurality of lenses include, in order from the object plane along an optical path, a first lens unit having a positive power, a second lens unit having a negative power, a third lens unit having a positive power, a fourth lens unit having a negative power, and a fifth lens unit having a positive power, and
wherein the projection optical system satisfies following equations where NAO is a numerical aperture of the projection optical system on the object plane, β is an imaging magnification of the projection optical system, Td is a distance on an optical axis from the object plane to the image plane, Dt is a sum of thicknesses of the glass materials on the optical axis in the projection optical system, OB 1 max is a maximum object height on the object plane, and OB 2 max is a maximum image height on the image plane:
0.125≦NAO
−0.251<β<−0.249
80 mm≦| OB 1max|
20 mm≦| OB 2max|
| Dt /( NAO·|OB 1max|)|≦62.0
Dt/Td≦ 0.645
0.072≦| OB 1max|/ Td 1.
9. A device manufacturing method comprising:
exposing a substrate using an exposure apparatus; and
developing the substrate that has been exposed,
wherein the exposure apparatus uses an i-line as a light source, and includes a projection optical system configured to project a pattern of an original that is placed on an object plane onto a substrate that is placed on an image plane,
wherein the projection optical system includes a plurality of lenses made of a plurality of types of different glass materials which include a lens having an Abbe number equal to or smaller than 62,
wherein the plurality of lenses include, in order from the object plane along an optical path, a first lens unit having a positive power, a second lens unit having a negative power, a third lens unit having a positive power, a fourth lens unit having a negative power, and a fifth lens unit having a positive power, and
wherein the projection optical system satisfies following equations where NAO is a numerical aperture of the projection optical system on the object plane, β is an imaging magnification of the projection optical system, Td is a distance on an optical axis from the object plane to the image plane, Dt is a sum of thicknesses of the glass materials on the optical axis in the projection optical system, OB 1 max is a maximum object height on the object plane, and OB 2 max is a maximum image height on the image plane:
0.125≦NAO
−0.251<β<−0.249
80 mm≦| OB 1max|
20 mm≦| OB 2max|
| Dt /( NAO·|OB 1max|)|≦62.0
Dt/Td≦ 0.645
0.072 ≦|OB 1max|/ Td|.