Catadioptric reduction projection optical system
First Claim
1. A catadioptric reduction projection optical system for projecting a reduced image of a pattern of a first surface onto a second surface, including:
- a first lens unit G1 for refracting a light beam from said first surface;
a semi-transparent mirror having a plane parallel plate for reflecting the light beam from said first lens unit G1;
a concave reflecting mirror for returning the light beam from said semi-transparent mirror to said semi-transparent mirror while converging said light beam;
a second lens unit G2 of negative refractive power disposed between said semi-transparent mirror and said concave reflecting mirror;
a third lens unit G3 of positive refractive power for converging the light beam returned to said semi-transparent mirror by the reflection on said concave reflecting mirror and transmitted through said semi-transparent mirror and forming the reduced image of the pattern of said first surface on said second surface; and
stop means disposed between said semi-transparent mirror and said third lens unit G3.
1 Assignment
0 Petitions
Accused Products
Abstract
A catadioptric reduction projection optical system is of a construction in which an on-axis light beam is used in a catadioptric system, and is designed such that resolving power is not deteriorated and a stop can be disposed. The catadioptric reduction projection optical system has a first lens unit G1 having negative refractive power and diffusing a light beam from a reticle 1, a semi-transparent mirror 2 for transmitting therethrough or reflecting the light beam from the first lens unit G1, a second lens unit G2 having negative refractive power and widening the light beam reflected from the semi-transparent mirror 2, a concave reflecting mirror 4 for returning the light beam from the second lens unit G2 to the semi-transparent mirror 2 through the second lens unit G2 while converging that light beam, a third lens unit G3 having positive refractive power and converging the light beam returned to and transmitted through the semi-transmitted mirror 2 on a wafer 5, and a stop 6 disposed between the semi-transparent mirror 2 and the third lens unit G3.
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Citations
13 Claims
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1. A catadioptric reduction projection optical system for projecting a reduced image of a pattern of a first surface onto a second surface, including:
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a first lens unit G1 for refracting a light beam from said first surface; a semi-transparent mirror having a plane parallel plate for reflecting the light beam from said first lens unit G1; a concave reflecting mirror for returning the light beam from said semi-transparent mirror to said semi-transparent mirror while converging said light beam; a second lens unit G2 of negative refractive power disposed between said semi-transparent mirror and said concave reflecting mirror; a third lens unit G3 of positive refractive power for converging the light beam returned to said semi-transparent mirror by the reflection on said concave reflecting mirror and transmitted through said semi-transparent mirror and forming the reduced image of the pattern of said first surface on said second surface; and stop means disposed between said semi-transparent mirror and said third lens unit G3. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A catadioptric reduction projection optical system for projecting a reduced image of a pattern of a first surface onto a second surface, including:
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a semi-transparent mirror having a plane parallel plate for dividing the optical path of a light beam from said first surface into a reflecting optical path and a transmitting optical path; a concave reflecting mirror disposed on the reflecting optical path of an object light beam by said semi-transparent mirror for returning the light beam from said object to said semi-transparent mirror; an anterior lens unit disposed between said semi-transparent mirror and said first surface; an intermediate lens unit of negative refractive power disposed between said semi-transparent mirror and said concave reflecting mirror; a posterior lens unit of positive refractive power for converging the light beam returned to said semi-transparent mirror by said concave reflecting mirror and transmitted through said semi-transparent mirror and forming the reduced image of the pattern of said first surface on said second surface; and stop means disposed between said semi-transparent mirror and said posterior lens unit. - View Dependent Claims (9, 10)
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11. A catadioptric reduction projection optical system for reduction projecting a pattern of a first surface onto a second surface, including:
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a beam splitter for splitting an optical path of a light beam from the first surface into a reflection optical path and a transmission optical path; a concave reflecting mirror disposed in said reflection optical path of the light beam from the first surface for returning the light beam from the first surface to said beam splitter; an anterior lens unit disposed between said beam splitter and said first surface; an intermediate lens unit disposed between said beam splitter and said concave reflecting mirror; a posterior lens unit of positive refractive power for converging a light beam having been returned to said beam splitter by said concave reflecting mirror and transmitted by the beam splitter so as to form a reduced image of said pattern of said first surface on said second surface; and a stop means disposed in a light path of the light beam transmitted by said beam splitter and between said beam splitter and said posterior lens unit. - View Dependent Claims (12, 13)
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Specification