Lithographic apparatus
AssigneeASML Netherlands B.V.
InventorsCheng-Qun Gui, Henricus Wilhelmus Maria Van Buel, Maurits Van Der Schaar, Arie Jeffrey Den Boef
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Abstract
A lithographic projection apparatus is provided with an optical system built into the wafer table for producing an image of a wafer mark that is provided on the back side of the wafer. The image is located at the plane of the front side of the wafer and can be viewed by an alignment system from the front side of the wafer. Simultaneous alignment between marks on the back and front of the wafer and a mask can be performed using a pre-existing alignment system.
Claims42
An alignment apparatus comprising:
- a substrate table constructed and arranged to support a substrate, said substrate including a backside having at least one alignment mark thereon, at least a portion of said backside being in contact with said substrate table,
- a redirecting optical system arranged entirely in said substrate table and configured to transmit light from said at least one alignment mark to a location proximate a perimeter of said substrate;
- and
- a relay optical system in optical communication with said redirecting optical system and configured to relay transmitted light from the location to a detector,
- wherein said relay optical system and said redirecting optical system are located on opposite sides of said substrate.
A lithographic projection apparatus comprising:
- a patterning structure constructed and arranged to pattern a beam of radiation;
- a projection system constructed and arranged to project said patterned beam of radiation onto a layer of photosensitive material disposed on a front side of a substrate, said substrate including a backside opposite to said front side and said backside having at least one alignment mark thereon;
- a substrate table constructed and arranged to support said substrate, at least a portion of the backside of said substrate being in contact with said substrate table,
- a redirecting optical system including at least one lens element arranged in said substrate table and configured to transmit light from said at least one alignment mark to a location proximate a perimeter of said substrate;
- and
- a relay optical system in optical communication with said redirecting optical system and configured to relay transmitted light from the location to a detector,
- wherein said relay optical system and said redirecting optical system are located on opposite sides of said substrate.
A method for aligning a substrate, said substrate being supported by a movable substrate table and including a backside having at least one alignment mark provided thereon, at least a portion of said backside being in contact with said substrate table, the method comprising:
- transmitting light from said at least one alignment mark to a location proximate a perimeter of said substrate with a redirecting optical system including at least one lens element arranged in said substrate table;
- projecting, with a relay optical system, a transmitted light from said at least one alignment mark at said location by said redirecting optical system;
- and
- detecting, with a detector, a projected light by said relay optical system
- wherein said redirecting optical system and said relay optical system are located on opposite sides of said substrate.
A lithographic projection apparatus comprising:
- a patterning structure which can be used to pattern a projection beam according to a desired pattern;
- a movable substrate table to hold a substrate;
- a projection system to project the patterned beam onto a target portion on a front side of the substrate;
- and
- an alignment system, located on a same side of the substrate as the projection system, to align a pattern of the patterning structure with an alignment mark provided on the substrate, using alignment radiation,
- wherein the movable substrate table comprises a redirecting optical system including at least one lens element and at least one mirror element to transmit an image of the alignment mark, for use by the alignment system, from a side of the substrate opposite the target portion.
A substrate table comprising:
- a body constructed and arranged to support a substrate, said substrate including at least one alignment mark provided thereon;
- and
- a redirecting optical system arranged in said body and including at least one lens element and being configured to transmit light from said at least one alignment mark to a location proximate a perimeter of said substrate,
- wherein said redirecting optical system has a folded optical axis having a first end portion and a second end portion, said first and second end portions being substantially parallel to each other and arranged to transmit light in opposite directions.
Dependencies are inferred from the claim text.