Scanning exposure apparatus and device manufacturing method

A device manufacturing method wherein a first movable stage being movable while carrying a first object thereon and a second movable stage being movable while carrying a second object thereon are scanningly moved in synchronism with each other and relative to a projection optical system so that a pattern of the first object is projected onto the second object, said method comprising the steps of:

• detecting, sequentially, positions of marks provided on the first movable stage and spaced apart in a scan direction, relative to the projection optical system and with respect to an exposure optical axis direction, as the first movable stage is moved to place, sequentially, the marks in a detection position;
• measuring a position of the first movable stage with respect to the scan direction;
• storing the positions with respect to the optical axis direction as detected in said detecting step and the position with respect to the scan direction at the corresponding moment;
• and
• correcting, during the scan of the first object and the second object, a positional relation between the projection optical system and a surface of the second object, with respect to the optical axis direction, on the basis of the stored positional relation between the marks and the projection optical system.

A method of manufacturing a device utilizing a scanning exposure apparatus including a mask stage having provided thereon a plurality of reference plates spaced apart in a scan direction, a wafer stage having provided thereon at least one reflection surface plate, and a projection optical system for projecting a pattern of a mask carried on the mask stage onto a wafer carried on the wafer stage as the mask stage and wafer stage are moved synchronously relative to one another, the method comprising the steps of:

• driving the mask stage so that, sequentially, a respective one of the plurality of reference plates is aligned with an optical axis of the projection optical system;
• positioning the wafer stage so that the reflection surface plate is in line with the optical axis;
• illuminating, while each respective reference plate is aligned with the optical axis, at least one mark on the reference plate so that light passing through the mark passes through the projection optical system and is reflected by the reflection surface plate;
• moving, while the at least one mark on each respective reference plate is being illuminated, the wafer stage in the direction of the optical axis;
• determining, based on the light reflected by the reflection surface plate, a preferred level along the optical axis for the wafer stage where imaging occurs when the at least one mark on each respective reference plate is illuminated;
• storing the preferred levels for the wafer stage in association with corresponding positions of the reference plates along the scan direction;
• calculating a degree of tilt of the mask stage in the scan direction based on the stored preferred levels for the wafer stage and corresponding positions of the reference plates;
• and
• controlling, during a scan operation in which the mask pattern is projected onto the wafer, the level of the wafer stage to compensate for the degree of tilt of the mask stage.

A scanning exposure apparatus, comprising:

• a first movable stage being movable while carrying a first object thereon;
• a second movable stage being movable while carrying a second object thereon;
• scanning means for scanningly moving said first and second stages in synchronism with each other and relative to a projection optical system so as to project the pattern of the object onto the second object through the projection optical system;
• reference plates provided on said first movable stage and having predetermined patterns, said first movable stage being movable so as to place, sequentially, each of said reference plates at a detection position;
• detecting means for detecting positions of said reference plates with respect to an exposure optical axis direction of the projection optical system as each of said reference plates is placed, sequentially, at the detection position;
• measuring means for measuring a position of said first movable stage with respect to the scan direction;
• storing means for storing therein the positions with respect to the optical axis direction as detected by said detecting means and the position with respect to the scan direction at the corresponding moment;
• and
• correcting means for correcting, during the scan of the first and second objects, a positional relation between the projection optical system and a surface of the second object to be exposed, with respect to the optical axis direction, on the basis of the stored positional relation between the reference plates and the projection optical system.

A scanning exposure apparatus for exposing a wafer to a pattern formed on a mask through a projection optical system, while a mask stage carrying the mask thereon and a wafer stage carrying the wafer thereon are scanningly moved in a timed relation with each other, said exposure apparatus comprising:

• reference marks provided on the mask stage and being arrayed along a scan direction, wherein the mask stage is movable so as to place at least one of said reference marks at a detection position;
• detecting means for detecting a positional relation between the projection optical system and the at least one of said reference marks, in an optical axis direction of the projection optical system;
• and
• correcting means for correcting a positional relation between the projection optical system and a pattern surface of the mask, in the optical axis direction, on the basis of the detected positional relation between the projection optical system and the at least one of said reference marks.

A device manufacturing method using a scanning exposure apparatus for exposing a wafer to a pattern formed on a mask through a projection optical system, while a mask stage carrying the mask thereon and a wafer stage carrying the wafer thereon are scanningly moved in a timed relation with each other, said method comprising:

• providing reference marks on the mask stage, the reference marks being arrayed along a scan direction;
• moving the mask stage so as to place at least one of the reference marks at a detection position;
• detecting a positional relation between the projection optical system and the at least one of the reference marks, in an optical axis direction of the projection optical system;
• and
• correcting a positional relation between the projection optical system and a pattern surface of the mask, in the optical axis direction, on the basis of the detected positional relation between the projection optical system and the at least one of the reference marks.

A scan transfer apparatus in which, while an original stage having an original placed thereon and a substrate stage having a substrate placed thereon are relatively scanningly moved, a pattern formed on the original is transferred onto the substrate by exposure through a projection optical system, said apparatus comprising:

• reference marks provided on the original stage, said reference marks being arranged along a scan direction, wherein the original stage is movable so as to sequentially position each of said reference marks at a detection position;
• detecting means for detecting each of position relations between the substrate and each of said reference marks on the original stage, in an optical axis direction of the projection optical system;
• and
• correcting means for correcting a positional relation between the substrate and the original, in the optical axis direction, on the basis of the detected positional relations.