Apparatus and methods for inhibiting immersion liquid from flowing below a substrate

Abstract

A substrate stage is provided with an immersion liquid collection member that surrounds at least an alignment feature of the substrate stage used to align the substrate on the stage by engaging alignment structure of the substrate. The collection member is located at least partly below the periphery of the substrate held by the substrate holding member of the substrate stage. The collection member has an uppermost liquid-receiving surface that preferably is spaced below a lowermost surface of the substrate when the substrate is held by the substrate holding member. The collection member collects liquid that flows along the alignment feature so as to prevent that immersion liquid from flowing along the under-surface of the substrate.

1 . A lithographic exposure apparatus that exposes a substrate by forming an image of a pattern through an immersion liquid onto the substrate, the lithographic exposure apparatus comprising:
 a projection optical system that projects the image of the pattern onto the substrate; and   a substrate stage that includes a substrate holding member that holds the substrate adjacent to a last optical element of the projection optical system with a gap between the last optical element and a surface of the substrate onto which the pattern is projected, the immersion liquid at least partially filling the gap,   the substrate stage including at least one alignment feature that engages an alignment structure on an outer periphery of the substrate to fix a position of the substrate on the substrate holding member,   the substrate stage including an immersion liquid collection member disposed so as to be located at least partly below the periphery of the substrate held by the substrate holding member, the collection member surrounding the at least one alignment feature, the collection member having an uppermost liquid-receiving surface that is spaced below a lowermost surface of the substrate when the substrate is held by the substrate holding member.   
   
   
       2 . The apparatus of  claim 1 , wherein the collection member extends around the entire periphery of the substrate. 
   
   
       3 . The apparatus of  claim 1 , wherein the collection member is a hydrophilic member that attracts the immersion liquid. 
   
   
       4 . The apparatus of  claim 1 , wherein the collection member includes a porous member, the porous member communicates with a low pressure source that draws collected immersion liquid from the porous member. 
   
   
       5 . The apparatus of  claim 4 , wherein the substrate stage includes a recess, the porous member is disposed in the recess, and a low-pressure passage communicates with the recess. 
   
   
       6 . The apparatus of  claim 1 , wherein the substrate stage includes a recess, the collection member is disposed in the recess. 
   
   
       7 . The apparatus of  claim 1 , wherein the collection member includes a first portion and a second portion, the first portion is located radially inward of the second portion so that the first portion is disposed closer to a center of the substrate holding member than is the second portion, at least a part of the first portion is disposed below the periphery of the substrate, a surface of the first portion is hydrophobic so as to repel the immersion liquid to assist in causing the immersion liquid to move from the first portion toward the second portion. 
   
   
       8 . The apparatus of  claim 7 , wherein the second portion is a hydrophilic member that attracts the immersion liquid from the first portion. 
   
   
       9 . The apparatus of  claim 8 , further comprising a low-pressure passage communicating with the hydrophilic member to remove immersion liquid from the hydrophilic member. 
   
   
       10 . The apparatus of  claim 9 , wherein the second portion is tapered so that a distance between a plane containing the substrate and an upper surface of the second portion increases as the upper surface progresses radially away from the substrate holding member. 
   
   
       11 . The apparatus of  claim 8 , wherein the second portion is tapered so that a distance between a plane containing the substrate and an upper surface of the second portion increases as the upper surface progresses radially away from the substrate holding member. 
   
   
       12 . The apparatus of  claim 11 , wherein the collection member includes a third portion located radially outward of the second portion, the third portion is a porous member and receives immersion liquid from the first and second portions, the porous member communicates with a low pressure source that draws collected immersion liquid from the porous member. 
   
   
       13 . The apparatus of  claim 12 , wherein at least part of the first portion is tapered. 
   
   
       14 . The apparatus of  claim 7 , wherein the second portion is a porous member and receives immersion liquid from the first portion, the porous member communicates with a low pressure source that draws collected immersion liquid from the porous member. 
   
   
       15 . The apparatus of  claim 14 , wherein at least part of the first portion is tapered so that a distance between a plane containing the substrate and an upper surface of the first portion increases as the upper surface progresses radially away from the substrate holding member. 
   
   
       16 . The apparatus of  claim 15 , wherein the collection member includes a third portion located radially outward of the second portion, the third portion is a hydrophilic member so as to attract immersion liquid from the first portion toward the second and third portions. 
   
   
       17 . The apparatus of  claim 14 , wherein the collection member includes a third portion located radially outward of the second portion, the third portion is a hydrophilic member so as to attract immersion liquid from the first portion toward the second and third portions. 
   
   
       18 . The apparatus of  claim 7 , wherein:
 the substrate holding member includes a plurality of protrusions that contact a lower surface of the substrate,   the first portion of the collection member includes at least one protrusion disposed below the substrate and having a height that is less than a height of the substrate holding member protrusions.   
   
   
       19 . The apparatus of  claim 18 , wherein the second portion is a hydrophilic member that attracts the immersion liquid from the first portion. 
   
   
       20 . The apparatus of  claim 19 , further comprising a low-pressure passage communicating with the hydrophilic member to remove immersion liquid from the hydrophilic member. 
   
   
       21 . The apparatus of  claim 20 , wherein the second portion is tapered so that a distance between a plane containing the substrate and an upper surface of the second portion increases as the upper surface progresses radially away from the substrate holding member. 
   
   
       22 . The apparatus of  claim 19 , wherein the second portion is tapered so that a distance between a plane containing the substrate and an upper surface of the second portion increases as the upper surface progresses radially away from the substrate holding member. 
   
   
       23 . The apparatus of  claim 22 , wherein the collection member includes a third portion located radially outward of the second portion, the third portion is a porous member and receives immersion liquid from the first and second portions, the porous member communicates with a low pressure source that draws collected immersion liquid from the porous member. 
   
   
       24 . The apparatus of  claim 23 , wherein at least part of the first portion is tapered. 
   
   
       25 . The apparatus of  claim 18 , wherein the second portion is a porous member and receives immersion liquid from the first portion, the porous member communicates with a low pressure source that draws collected immersion liquid from the porous member. 
   
   
       26 . The apparatus of  claim 25 , wherein at least part of the first portion is tapered so that a distance between a plane containing the substrate and an upper surface of the first portion increases as the upper surface progresses radially away from the substrate holding member. 
   
   
       27 . The apparatus of  claim 26 , wherein the collection member includes a third portion located radially outward of the second portion, the third portion is a hydrophilic member so as to attract immersion liquid from the first portion toward the second and third portions. 
   
   
       28 . The apparatus of  claim 25 , wherein the collection member includes a third portion located radially outward of the second portion, the third portion is a hydrophilic member so as to attract immersion liquid from the first portion toward the second and third portions. 
   
   
       29 . The apparatus of  claim 1 , wherein the at least one alignment feature has a hydrophobic surface that repels the immersion liquid. 
   
   
       30 . The apparatus of  claim 1 , further comprising:
 an immersion fluid supply system that supplies an immersion liquid to an immersion area that is formed in the gap between the projection optical system and the substrate held by the substrate stage.   
   
   
       31 . A process for manufacturing a device comprising the steps of providing a substrate and transferring an image onto the substrate utilizing the lithographic exposure apparatus of  claim 30 . 
   
   
       32 . A lithographic exposure apparatus that exposes a substrate by forming an image of a pattern through an immersion liquid onto the substrate, the lithographic exposure apparatus comprising:
 a projection optical system that projects the image of the pattern onto the substrate; and   a substrate stage that includes a substrate holding member that holds the substrate adjacent to a last optical element of the projection optical system with a gap between the last optical element and a surface of the substrate onto which the pattern is projected, the immersion liquid at least partially filling the gap,   the substrate holding member of the substrate stage including a plurality of protrusions that engage a lower surface of the substrate to assist in holding the substrate to the substrate stage, outermost ones of the protrusions being hydrophobic so as to repel the immersion liquid.   
   
   
       33 . The apparatus of  claim 32 , wherein the hydrophobic protrusions have a height that is less than a height of the protrusions that are not hydrophobic. 
   
   
       34 . A method of forming an image of a pattern onto a substrate, the method comprising:
 holding the substrate on a substrate stage of a lithographic exposure apparatus with a substrate holding member of the substrate stage, the substrate stage including at least one alignment feature that engages an alignment structure on an outer periphery of the substrate to fix a position of the substrate on the substrate holding member;   projecting the image through a projection optical system of the lithographic exposure apparatus and onto a surface of the substrate held by the substrate holding member while an immersion liquid is disposed in at least a part of a gap between a last optical element of the projection optical system and the surface of the substrate, the image being projected onto the surface of the substrate after passing through the immersion liquid; and   collecting immersion liquid that overflows the periphery of the substrate with an immersion liquid collection member disposed so as to be located at least partly below the periphery of the substrate held by the substrate holding member, the collection member surrounding the at least one alignment feature, the collection member having an uppermost liquid-receiving surface that is spaced below a lowermost surface of the substrate when the substrate is held by the substrate holding member.   
   
   
       35 . The method of  claim 34 , wherein the collection member extends around the entire periphery of the substrate. 
   
   
       36 . The method of  claim 34 , wherein the collection member is a hydrophilic member that attracts the immersion liquid. 
   
   
       37 . The method of  claim 34 , wherein the collection member is a porous member, and further comprising drawing collected immersion liquid from the porous member with a low pressure source that communicates with the porous member via a low-pressure passage. 
   
   
       38 . The method of  claim 37 , wherein the substrate stage includes a recess, the porous member is disposed in the recess, and the low-pressure passage communicates with the recess. 
   
   
       39 . The method of  claim 34 , wherein the substrate stage includes a recess, the collection member is disposed in the recess. 
   
   
       40 . The method of  claim 34 , wherein the collection member includes a first portion and a second portion, the first portion is located radially inward of the second portion so that the first portion is disposed closer to a center of the substrate holding member than is the second portion, at least a part of the first portion is disposed below the periphery of the substrate, a surface of the first portion is hydrophobic so as to repel the immersion liquid to assist in causing the immersion liquid to move from the first portion toward the second portion. 
   
   
       41 . The method of  claim 40 , wherein the second portion is a hydrophilic member that attracts the immersion liquid from the first portion. 
   
   
       42 . The method of  claim 41 , further comprising removing immersion liquid from the hydrophilic member via a low-pressure passage that communicates with a low-pressure source. 
   
   
       43 . The method of  claim 42 , wherein the second portion is tapered so that a distance between a plane containing the substrate and an upper surface of the second portion increases as the upper surface progresses radially away from the substrate holding member. 
   
   
       44 . The method of  claim 41 , wherein the second portion is tapered so that a distance between a plane containing the substrate and an upper surface of the second portion increases as the upper surface progresses radially away from the substrate holding member. 
   
   
       45 . The method of  claim 44 , wherein the collection member includes a third portion located radially outward of the second portion, the third portion is a porous member and receives immersion liquid from the first and second portions, the porous member communicates with a low pressure source that draws collected immersion liquid from the porous member. 
   
   
       46 . The method of  claim 45 , wherein at least part of the first portion is tapered. 
   
   
       47 . The method of  claim 40 , wherein the second portion is a porous member and receives immersion liquid from the first portion, the porous member communicates with a low pressure source that draws collected immersion liquid from the porous member. 
   
   
       48 . The method of  claim 47 , wherein at least part of the first portion is tapered so that a distance between a plane containing the substrate and an upper surface of the first portion increases as the upper surface progresses radially away from the substrate holding member. 
   
   
       49 . The method of  claim 48 , wherein the collection member includes a third portion located radially outward of the second portion, the third portion is a hydrophilic member that attracts immersion liquid from the first portion toward the second and third portions. 
   
   
       50 . The method of  claim 47 , wherein the collection member includes a third portion located radially outward of the second portion, the third portion is a hydrophilic member that attracts immersion liquid from the first portion toward the second and third portions. 
   
   
       51 . The method of  claim 40 , wherein the substrate holding member includes a plurality of protrusions that contact a lower surface of the substrate, and further comprising:
 inhibiting immersion liquid from flowing along an under-surface of the substrate by disposing at least one protrusion on the first portion, the at least one protrusion being hydrophobic, being disposed below the substrate and having a height that is less than a height of the substrate holding member protrusions.   
   
   
       52 . The method of  claim 51 , wherein the at least one alignment feature has a hydrophobic surface that repels the immersion liquid.