JP2011082311A5

JP2011082311A5 -

Info

Publication number: JP2011082311A5
Application number: JP2009232865A
Authority: JP
Filing date: 2009-10-06
Publication date: 2012-11-08
Anticipated expiration: 2029-10-06

Description

ところが、湾曲した平行平板を投影光学系の光路中に配すると倍率を補正することができるが、非点収差が新たに発生することがわかった。例えば、下側平行平板を走査方向の倍率補正に使用する場合、拡大するためには上面がふくらみ、下面が窪んだ湾曲を走査方向に与え直交する方向には平面のままとなるような変形を与えることになる。このとき、走査方向に直交する方向の屈折力は変化しないが走査方向には負の屈折力が生じる。このため、走査方向の線像（以後Ｖ線）の結像位置は、そのままである走査直交方向の線像（以後Ｈ線）より光学系から遠くに離れた位置つまりは下側に結像するようになる。発明者の計算では、走査方向に１０ｐｐｍ拡大される（像が１．００００１倍になる）とき、ＨＶ線の非点収差は約５μｍ（Ｈ線が下）になる。さらに、特許文献１に記載されているように上側平行平板を走査方向に直交する方向の倍率補正に使用した場合、像面側で拡大するためには上方に向かって窪んだ湾曲を走査方向と直交する方向に与える。このとき、結像系の側から物体面側を見ると、走査方向の屈折力は変化しないが走査方向と直交する方向には正の屈折力が生じ、走査方向と直交する方向には倍率が縮小されＶ線がＨ線より結像系に近い側に結像するようになる。これを順方向に物体面側から像面側への結像に光線を追跡し直すと、横収差である倍率は反転し、走査方向と直交する方向の倍率は拡大となり、縦収差である結像位置は保存されＨ線はＶ線に対し光学系から遠い位置、つまりは下側に結像する。まとめると、上側平行平板で走査方向直交する方向の倍率を拡大にするとＨ線が下になる非点収差が発生し、同様に下側平行平板で走査方向の倍率を拡大にするとＨ線が下になる非点収差が発生する。
However, it has been found that if a curved parallel plate is arranged in the optical path of the projection optical system, the magnification can be corrected, but astigmatism newly occurs. For example, when the lower parallel plate is used for magnification correction in the scanning direction, deformation is performed so that the upper surface swells and the lower surface is depressed in the scanning direction in order to enlarge, and remains flat in the orthogonal direction. Will give. At this time, the refractive power in the direction orthogonal to the scanning direction does not change, but negative refractive power is generated in the scanning direction. For this reason, the imaging position of the line image in the scanning direction (hereinafter referred to as V-line) is imaged at a position farther away from the optical system than the line image in the scanning orthogonal direction (hereinafter referred to as H-line). It becomes like this. According to the inventor's calculation, the astigmatism of the HV line is about 5 μm (the H line is below) when the image is magnified by 10 ppm in the scanning direction (the image becomes 1.00001 times). Further, when the upper parallel plate is used for magnification correction in the direction orthogonal to the scanning direction as described in Patent Document 1, in order to enlarge on the image plane side, a curve that is depressed upward is defined as the scanning direction. Give in the orthogonal direction. At this time, when the object plane side is viewed from the imaging system side, the refractive power in the scanning direction does not change, but a positive refractive power is generated in the direction orthogonal to the scanning direction, and the magnification is increased in the direction orthogonal to the scanning direction. The image is reduced and the V line is imaged closer to the imaging system than the H line. When the light beam is traced back in the forward direction from the object surface side to the image surface side, the lateral aberration magnification is reversed, the magnification in the direction orthogonal to the scanning direction is enlarged, and the longitudinal aberration is observed. The image position is preserved, and the H line is formed at a position far from the optical system with respect to the V line, that is, on the lower side. In summary, when the magnification in the direction orthogonal to the scanning direction is enlarged on the upper parallel plate, astigmatism that lowers the H line occurs. Similarly, when the magnification in the scanning direction is enlarged on the lower parallel plate, the H line is lowered. Astigmatism occurs.

本発明は、物体面側から順に、第１鏡、第１凹面鏡、凸面鏡、第２凹面鏡及び第２鏡が前記物体面から像面に至る光路に配置され、前記物体面と前記第１鏡との間の光路と前記第２鏡と前記像面との間の光路とが平行である投影光学系であって、前記物体面と前記第１鏡との間の光路に配置され、当該光路に沿う第１方向と直交する第２方向における前記投影光学系の倍率を補正する第１光学系と、前記第２鏡と前記像面との間の光路に配置され、前記第１方向及び前記第２方向と直交する第３方向における前記投影光学系の倍率を補正する第２光学系と、前記物体面と前記第１鏡との間の光路又は前記第２鏡と前記像面との間の光路に配置され、前記第２方向及び前記第３方向において同じ倍率で前記投影光学系の倍率を補正する第３光学系と、制御部と、を備え、前記投影光学系の前記第２方向及び前記第３方向における倍率の補正されるべき量をそれぞれＡ及びＢとし、前記第３光学系によって前記投影光学系の前記第２方向及び前記第３方向における倍率の補正量をＣとするとき、前記制御部は、前記補正量Ｃが前記補正されるべき量Ａと前記補正されるべき量Ｂとの間の量となり、前記第１光学系による前記第２方向における倍率の補正量が（Ａ−Ｃ）となり、前記第２光学系による前記第３方向における倍率の補正量が（Ｂ−Ｃ）となるように、前記第１光学系と前記第２光学系と前記第３光学系とを制御する、ことを特徴とする。 In the present invention, in order from the object plane side, a first mirror , a first concave mirror, a convex mirror, a second concave mirror, and a second mirror are arranged in an optical path from the object plane to the image plane, and the object plane and the first mirror A projection optical system in which an optical path between the second mirror and the image plane is parallel, and is disposed in an optical path between the object plane and the first mirror. A first optical system for correcting the magnification of the projection optical system in a second direction orthogonal to the first direction along the optical path between the second mirror and the image plane, and the first direction and the first direction A second optical system that corrects the magnification of the projection optical system in a third direction orthogonal to two directions, and an optical path between the object plane and the first mirror , or between the second mirror and the image plane. A third optical element disposed in the optical path and correcting the magnification of the projection optical system at the same magnification in the second direction and the third direction; And a control unit, and the amounts of the magnification in the second direction and the third direction of the projection optical system to be corrected are A and B, respectively, and the third optical system allows the projection optical system to When the correction amount of the magnification in the second direction and the third direction is C, the control unit determines that the correction amount C is an amount between the amount A to be corrected and the amount B to be corrected. The magnification correction amount in the second direction by the first optical system is (AC), and the magnification correction amount in the third direction by the second optical system is (BC). The first optical system, the second optical system, and the third optical system are controlled.

Claims

In order from the object plane side, a first mirror , a first concave mirror, a convex mirror, a second concave mirror, and a second mirror are arranged in an optical path from the object plane to the image plane, and an optical path between the object plane and the first mirror And a projection optical system in which an optical path between the second mirror and the image plane is parallel,
A first optical system that is disposed in an optical path between the object plane and the first mirror and corrects the magnification of the projection optical system in a second direction orthogonal to the first direction along the optical path;
A second optical system that is disposed in an optical path between the second mirror and the image plane and corrects the magnification of the projection optical system in the first direction and a third direction orthogonal to the second direction;
Magnification of the projection optical system disposed in the optical path between the object plane and the first mirror or in the optical path between the second mirror and the image plane and at the same magnification in the second direction and the third direction A third optical system for correcting
A control unit,
The amounts to be corrected for the magnification in the second direction and the third direction of the projection optical system are respectively A and B, and the third optical system in the second direction and the third direction of the projection optical system. When the magnification correction amount is C,
In the control unit, the correction amount C is an amount between the amount A to be corrected and the amount B to be corrected, and the correction amount of the magnification in the second direction by the first optical system is (A -C), and the first optical system, the second optical system, and the third optical system are adjusted so that the magnification correction amount in the third direction by the second optical system is (B-C). Control,
A projection optical system characterized by that.

The projection optical system according to claim 1, wherein both the object plane and the image plane have telecentricity.

The first optical system and the second optical system include a parallel plate that can be bent in the first direction and a plurality of cylindrical lenses, and a cylindrical that can change the interval in the first direction of the plurality of cylindrical lenses. Including at least one of the lens system,
Wherein the third optical system is a plano-convex lens and said plano-convex lens and the plano-concave lens capable of changing the distance in the first direction and the optical system has a plano-concave lens, a plano-concave lens which can be driven in the first direction or comprising a plano-convex lens, one of the projection optical system according to claim 1 or claim 2, characterized in that.

In the control unit, the correction amount C is (A + B) / 2, the magnification correction amount in the second direction by the first optical system is (A−B) / 2, and the second optical system performs the second correction. The first optical system, the second optical system, and the third optical system are controlled so that a magnification correction amount (BA) / 2 in three directions is obtained. The projection optical system according to claim 3.

A reticle pattern arranged on the object plane is projected onto the substrate arranged on the image plane using the projection optical system according to claim 1 to expose the substrate. An exposure apparatus characterized by the above.

A method of manufacturing a device comprising:
Exposing the substrate using the exposure apparatus according to claim 5;
Developing the exposed substrate;
A device manufacturing method including: