Lithographic apparatus, device manufacturing method and substrate holder
AssigneeASML Netherlands B.V.
InventorsRobertus Nicodemus Jacobus Van Ballegoij, Martinus Agnes Willem Cuijpers, Pieter Johannes Gertrudis Meijers, Gerardus Petrus Matthijs Van Nunen, Joost Jeroen Ottens
Life of this patent
Estimating the term…
Abstract
A substrate holder has burls having a height not less than 100 μm and at least 10 vacuum ports arranged within a central region extending to a radius of two thirds the radius of the substrate. Thereby concave wafers can be reliably clamped by generating an initial vacuum in a central region which exerts a clamping force tending to flatten the wafer and allowing the initial vacuum to deepen until the wafer is fully clamped.
Claims21
A lithographic apparatus, comprising:
- an illumination system constructed to provide a beam of radiation;
- a support structure to support a patterning device, said patterning device constructed to impart a cross-section of said beam of radiation with a pattern to form a patterned beam of radiation;
- a substrate holder for holding a substrate having a radius, said substrate holder including a plurality of protrusions upstanding from a surface and having substantially coplanar extremities, a wall surrounding said plurality of protrusions, and a plurality of vacuum ports opening into a space bounded by said wall;
- and
- a projection system constructed to project said patterned beam of radiation onto a target portion of said substrate,
- each of said plurality of vacuum parts opening into a central region of said space bounded by said wall, said central region having an outer radius of not more than 70% of said radius of said substrate.
A method of manufacturing a device, comprising:
- providing a substrate holder having a plurality of protrusions upstanding from a surface and having substantially coplanar extremities, a wall surrounding the plurality of protrusions and a plurality of vacuum ports opening into a space bounded by the wall, each of the vacuum ports being open into a central region of the space bounded by the wall, the central region having an outer radius of not more than 70% of a radius of a substrate configured to be held by the substrate holder;
- holding the substrate by evacuating the space between the substrate and the substrate holder;
- and
- projecting a patterned beam of radiation onto a target portion of the substrate.
A substrate holder comprising:
- a plurality of protrusions upstanding from a surface of said substrate holder and having substantially coplanar extremities;
- a wall surrounding said plurality of protrusions;
- and
- a plurality of vacuum ports opening into a space bounded by said wall,
- each of said vacuum ports opening into a central region of said space bounded by said wall, said central region having an outer radius of not more than 70% of a radius of a substrate configured to be held by the substrate holder.
Dependencies are inferred from the claim text.