Exposure tool and method capable of correcting high (N-TH) order light exposure errors depending upon an interfield coordinate
First Claim
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1. An exposure tool comprising:
- a wafer stage having a semiconductor wafer with a plurality of alignment marks formed thereon for position identification;
a wafer stage position measuring mechanism for measuring a position of the wafer stage;
a projection optical mechanism for projecting a circuit pattern onto the wafer to expose a predetermined area of the wafer with beam;
an alignment mechanism for detecting the positions of wafer in an aligned state;
a calculation mechanism for calculation-processing a signal obtained by processing an alignment output signal from the alignment mechanism and output signals obtained wafer stage position measuring mechanism; and
a control mechanism which, at a plurality of exposures of the wafer by the projection optical mechanism, controls the alignment mechanism in accordance with an n-th order function (x, y) in an interfield coordinate (x, y) of the wafer by approximating a per-exposure systematic error of at least one of a shot rotation error, magnification error and skew error with the n-th order function Ls (x, y) and corrects the per-exposure systematic error depending upon the interfield coordinate.
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Abstract
A light exposure tool of the present invention is so structured as to enable the correction of a linear intrafield error of a shot and of a higher-order intrafield error of the shot depending upon an interfield of a wafer. The light exposure tool comprises a reticle having a written circuit pattern, a reticle stage having the reticle placed on it, a reticle XY stage drive controller, a reticle stage position measuring mechanism, a wafer stage having a semiconductor wafer placed on it, the semiconductor wafer having a plurality of alignment marks formed on it for position identification, a wafer XY stage drive controller, a wafer stage position measuring mechanism, a projection optical mechanism for projecting the circuit pattern of the reticle onto the wafer to create a shot, an alignment mechanism for detecting positions of the alignment marks 9 and setting the reticle and wafer in a desired position, a calculation device, a shot rotation adjusting controller, and an isotropic magnification controller. At a time of light exposures by the projection optical mechanism on the wafer, a per-exposure systematic error of at least one of a rotation error, magnification error and skew error is approximated with an n-th order function Ls (x, y) in an interfield coordinate (x, y) of the wafer to control the alignment mechanism in accordance with the function Ls (x, y) and to correct the per-exposure systematic error depending upon the interfield coordinate of the wafer.
23 Citations
47 Claims
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1. An exposure tool comprising:
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a wafer stage having a semiconductor wafer with a plurality of alignment marks formed thereon for position identification; a wafer stage position measuring mechanism for measuring a position of the wafer stage; a projection optical mechanism for projecting a circuit pattern onto the wafer to expose a predetermined area of the wafer with beam; an alignment mechanism for detecting the positions of wafer in an aligned state; a calculation mechanism for calculation-processing a signal obtained by processing an alignment output signal from the alignment mechanism and output signals obtained wafer stage position measuring mechanism; and a control mechanism which, at a plurality of exposures of the wafer by the projection optical mechanism, controls the alignment mechanism in accordance with an n-th order function (x, y) in an interfield coordinate (x, y) of the wafer by approximating a per-exposure systematic error of at least one of a shot rotation error, magnification error and skew error with the n-th order function Ls (x, y) and corrects the per-exposure systematic error depending upon the interfield coordinate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A light exposure tool comprising:
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a reticle stage having a reticle placed thereon, the reticle having a circuit pattern written thereon and a plurality of alignment marks formed thereon; a wafer stage having a semiconductor wafer with a plurality of alignment marks formed thereon for position identification; a reticle stage position measuring mechanism for measuring a position of the reticle stage; a wafer stage position measuring mechanism for measuring a position of the wafer stage; a projection optical mechanism for projecting a circuit pattern of the reticle onto the wafer to expose a predetermined area of the wafer with light; an alignment mechanism for detecting the positions of alignment marks on the reticle and on the wafer and setting the reticle and wafer in an aligned state; a calculation mechanism for calculation-processing a signal obtained by processing an alignment output signal from the alignment mechanism and output signals obtained from the reticle stage position measuring mechanism and wafer stage position measuring mechanism; and a control mechanism which, at a plurality of exposures of the wafer by the projection optical mechanism, controls the alignment mechanism in accordance with an n-th order function (x, y) in an interfield coordinate (x, y) of the wafer by approximating a per-exposure systematic error of at least one of a shot rotation error, magnification error and skew error with the n-th order function Ls (x, y) and corrects the per-exposure systematic error depending upon the interfield coordinate. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A light exposure tool comprising:
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a reticle having a circuit pattern written thereon and a plurality of alignment marks formed thereon for position identification; a reticle stage with the reticle placed thereon; a reticle XY stage drive mechanism for driving the reticle stage in a translate direction; a wafer stage having a semiconductor wafer with a plurality of alignment marks formed thereon for position identification; a wafer XY stage drive mechanism for driving the wafer stage in a translate direction; a shot rotation adjusting mechanism for adjusting a stage in-plane rotation position of at least one of the reticle stage and wafer stage; a reticle stage position measuring mechanism for measuring a position of the reticle stage; a wafer stage position measuring mechanism for measuring a position of the wafer stage; a projection optical mechanism for projecting a circuit pattern of the reticle onto the wafer to create a shot; an alignment mechanism for detecting a position on the reticle and on the wafer and setting the reticle and wafer in an aligned position; a calculation mechanism for calculation-processing a signal obtained by processing an alignment output signal from the alignment mechanism and output signals obtained from the reticle stage position measuring mechanism and wafer stage position measuring mechanism; and correcting means for finding a shot rotation error θ
at each of a plurality of shots on the wafer, approximating the rotation error θ
with an n-th order function θ
s (x, y) in an interfield coordinate (x, y) of the wafer, and controlling the shot rotation adjusting mechanism in accordance with the function θ
s (x, y), thereby adjusting a stage in-plane rotation position of at least one of the reticle stage and wafer stage. - View Dependent Claims (27)
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28. A light exposure tool comprising:
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a reticle having a circuit pattern written thereon; a reticle stage having the reticle placed thereon; a reticle XY stage drive mechanism for driving the reticle stage in a translate direction; a wafer stage having a semiconductor wafer placed thereon; a wafer XY stage drive mechanism for driving the wafer stage in a translate direction; a reticle stage position measuring mechanism for measuring a position of the reticle stage; a wafer stage position measuring mechanism for measuring a position of the wafer stage; a projection optical mechanism for projecting the circuit pattern of the reticle onto the wafer to create a shot; an isotropic magnification adjusting mechanism for adjusting an isotropic magnification of a shot projected onto the wafer; an alignment mechanism for detecting positions of a plurality of alignment marks formed on the reticle and on the wafer for position identification and setting the reticle and wafer in a desired position; a calculation mechanism for calculation-processing a signal obtained by processing an alignment output signal from the alignment mechanism and output signals obtained from the reticle stage position measuring mechanism and wafer stage position measuring mechanism; and correcting means for adjusting the isotropic magnification of the shot by finding a magnification error M at each of a plurality of shots created on the wafer, approximating the magnification error M with an n-th order function M (x, y) in an interfield of the wafer and controlling the isotropic magnification adjusting mechanism in accordance with the function M (x, Y).
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29. A light exposure tool comprising:
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a reticle having a circuit pattern written thereon; a reticle stage having the reticle placed thereon; a reticle XY stage drive mechanism for driving the reticle stage in a translate direction; a wafer stage having a semiconductor wafer placed thereon; a wafer stage drive mechanism for driving the wafer stage in a translate direction; a shot rotation adjusting mechanism for adjusting a stage in-plane rotation position of at least one of the reticle stage and wafer stage; a reticle stage position measuring mechanism for measuring the position of the reticle stage; a wafer stage position measuring mechanism for measuring the wafer stage position; a projection optical mechanism for projecting the circuit pattern of the reticle onto the wafer to create a shot; an isotropic magnification adjusting mechanism for adjusting the isotropic magnification of the shot created on the projected wafer; an alignment mechanism for detecting positions of a plurality of alignment marks formed on the reticle and on the wafer for position identification and setting the reticle and wafer in a desired position; a calculation mechanism for calculation-processing a signal obtained by processing an alignment output signal from the alignment mechanism and output signals obtained from the reticle stage position measuring mechanism and wafer stage position measuring mechanism; and correcting means for, while adjusting a stage in-plane rotation position of at least one of the reticle stage and wafer stage in accordance with an n-th order function Ls (x, y) in an interfield coordinate (x, y) of the wafer, correcting an isotropic magnification of the shot by finding a shot rotation error and magnification error at each of a plurality of shots created on the wafer, approximating the shot rotation error and magnification error with the n-th order function Ls (x, y) in the interfield coordinate (x, y) of the wafer and controlling the shot rotation adjusting mechanism and isotropic magnification adjusting mechanism in accordance with the function Ls (x, y).
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30. A scan type light exposure tool for effecting light exposure under relative movement of a reticle and wafer at a time of creating a shot by projecting, on a mask placed on a mask stage, a circuit pattern written on the reticle which is placed on a reticle stage, comprising:
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a shot rotation correcting mechanism for correcting a rotation of a shot during light exposure; and correcting means for correcting a stage in-plane rotation position of at least one of the reticle stage and wafer stage by finding a shot rotation error at each of a plurality of shots created on the wafer, approximating the shot rotation error with an n-th order function θ
s (x, y) in an interfield coordinate (x, y) and controlling the shot rotation correcting mechanism in accordance with the function θ
s (x, y).
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31. A scan-type light exposure tool for effecting light exposure under relative movement of a reticle and wafer at a time of creating a shot by projecting, on a mask placed on a mask stage, a circuit pattern written on the reticle which is placed on a reticle stage, comprising:
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a shot magnification correcting mechanism for correcting a magnification of a shot during light exposure; and correcting means for correcting a shot magnification by finding a magnification error (Mx, My) at each of a plurality of shots created on the wafer, approximating the magnification error with an n-th order function (x, y) in an interfield coordinate (x, y) of the wafer and controlling the shot magnification correcting mechanism in accordance with the function M (x, y).
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32. A scan type light exposure tool for effecting light exposure under relative movement of a reticle and wafer at a time of creating a shot by projecting, on a mask placed on a mask stage, a circuit pattern written on a reticle placed on a reticle stage, comprising:
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a shot skew correcting mechanism for correcting a skew of a shot during light exposure; and correcting means for correcting the shot skew by finding a skew error θ
so at each of a plurality of shots on the wafer, approximating the skew error with an n-th order function θ
so (x, y) in an interfield coordinate (x, y) of the wafer and controlling the shot skew correcting mechanism.
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33. A scan type light exposure tool for effecting light exposure under relative movement of a reticle and wafer at a time of creating a shot by projecting, on a mask placed on a mask stage, a circuit pattern written on a reticle which is placed on a reticle stage, comprising:
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a correcting mechanism for correcting shot rotation, magnification and skew errors of a shot during light exposure; and correcting means for correcting shot rotation, magnification and skew errors at each of a plurality of shots created on the wafer by finding a rotation error θ
s, magnification error (Mx, My) and skew error θ
so at each shot, approximating an n-th order function Ls (x, y) in an interfield coordinate of the wafer and controlling the correcting mechanism in accordance with the function Ls (x, y).
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34. A mask pattern light exposure tool for exposing, with light, a circuit pattern on a mask placed on a mask stage, comprising:
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a correction mechanism for correcting at least one of a shot rotation (θ
s), shot magnification (Mx+My) and shot skew (θ
so) upon exposing the mask with the light; andcontrol means for effecting control by finding at least one of systematic errors (θ
s, Mx, My, θ
so) at each of a plurality of shots created on the mask, approximating, with an n-th order function Ls (x, y) in a coordinate (x, y) in a mask plane, at least one of a shot rotation error, magnification error and skew error and positioning the mask stage in accordance with the function Ls (x, y).
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35. A method for writing a circuit pattern with an exposure tool for writing a circuit pattern by a beam on a semiconductor wafer placed on a wafer stage comprising the steps of:
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effecting calculation-processing by finding at least one of systematic errors Ls (θ
s, Mx, My θ
so) at each of a plurality of shots created on the wafer and approximating at least one of a shot rotation error, magnification error and skew error with an n-th order function Ls (x, y) in an interfield coordinate (x, y) of the wafer; andeffecting control by correcting at least one of a shot rotation (θ
s), shot magnification (Mx, My) and shot skew (θ
so), during the writing of the circuit pattern on the wafer, in accordance with the function Ls (x, y).
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36. A method for effecting light exposure with a light exposure tool for projecting, on a semiconductor wafer placed on a wafer stage, a circuit pattern written on a reticle which is placed on a reticle stage, comprising the steps of:
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effecting calculation-processing by approximating a per-exposure systematic error consisting of at least one of a shot rotation error, magnification error and skew error at a plurality of light exposures of the wafer with an n-th order function Ls (x, y) in an interfield coordinate (x, y) of the wafer; and effecting control by adjusting a position in a stage plane of at least one of the reticle stage and wafer stage in accordance with the function Ls (x, y). - View Dependent Claims (37, 38, 39, 40)
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41. A method for effecting light exposure on a light exposure tool for creating a shot by projecting, on a semiconductor wafer placed on a wafer stage, a circuit pattern written on a reticle which is placed on a reticle stage, comprising:
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effecting calculation-processing by finding a shot rotation error θ
at each of a plurality of shots created on the wafer and approximating the shot rotation error θ
with an n-th order function θ
s (x, y) in an interfield coordinate (x, y) of the wafer; andeffecting control by adjusting a rotation position in a stage plane of at least one of the reticle stage and wafer stage in accordance with the function θ
s (x, y).
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42. A method for effecting light exposure on a light exposure tool for creating a shot by projecting, on a semiconductor wafer placed on a wafer stage, a circuit pattern written on a reticle which is placed on a reticle stage, comprising:
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effecting calculation-processing by finding a magnification error θ
at each of a plurality of shots created on the wafer and approximating the magnification error θ
with an n-th order function θ
s (x, y) in an interfield coordinate (x, y) of the wafer; andeffecting control by adjusting an isotropic magnification of the shot in accordance with the function θ
s (x, y).
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43. A method for effecting light exposure on a light exposure tool for creating a shot by projecting, on a semiconductor wafer placed on a wafer stage, a circuit pattern written on a reticle which is placed on a reticle stage, comprising:
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effecting calculation processing by finding a rotation error and magnification error at each of a plurality of shots created on the wafer and approximating the shot rotation error and magnification error with an n-th order function Ls (x, y) in an interfield coordinate (x, y) of the wafer; and effecting control by adjusting an isotropic magnification of the shot while adjusting a shot rotation position in a stage plane of at least one of the reticle stage and wafer stage in accordance with the function Ls (x, y).
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44. A method for effecting light exposure on a light exposure tool for creating a shot by projecting, on a semiconductor wafer placed on a wafer stage, a circuit pattern written on a reticle which is placed on a reticle stage, comprising:
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effecting calculation-processing by measuring, by an alignment mechanism, at least one of a shot rotation error θ
s (x, y), shot magnification error (Mx, My) and shot skew errors θ
s (x, y) at a plurality of shots created on a wafer with respect to a predetermined specific wafer and approximating a measurement error with an n-th order function Ls (x, y) in an interfield coordinate (x, y) of the wafer; andeffecting control by, after adjusting at least one of the shot rotation error, magnification error and skew error in accordance with the function Ls (x, y), sequentially exposing the specific wafer and other wafers.
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45. A method for exposing, with light, a circuit pattern on a mask placed on a mask stage, comprising the steps of:
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effecting calculation-processing by finding at least one of systematic errors Ls (θ
s, Mx, My, θ
so) at each of a plurality of shots created on the mask and approximating at least one of a shot rotation error, magnification error and skew error with an n-th order function Ls (x, y) in a coordinate (x, y) in a mask plane; andeffecting control by correcting at least one of a shot rotation (θ
s), shot magnification (Mx, My) and shot skew (θ
so), a during the exposure of the mask with the light, in accordance with the function Ls (x, y).
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46. A method for writing a circuit pattern with an electronic beam exposure tool for writing a circuit pattern by an electronic beam on a semiconductor wafer placed on a wafer stage, comprising the steps of:
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effecting calculation-processing by finding at least one of systematic errors Ls (θ
s, Mx, My, θ
so) at each of a plurality of shots created on the wafer and approximating at least one of a shot rotation error, magnification error and skew error with an n-th order function Ls (x, y) in an interfield coordinate (x, y) of the wafer; andeffecting control by correcting at least one of a shot rotation (θ
s), shot magnification (Mx, My) and shot skew (θ
so), during the writing of the circuit pattern on the wafer, in accordance with the function Ls (x, y). - View Dependent Claims (47)
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Specification
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Current AssigneeKabushiki Kaisha Toshiba (Toshiba Corporation)
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Original AssigneeKabushiki Kaisha Toshiba (Toshiba Corporation)
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InventorsHigashiki, Tatsuhiko, Asanuma, Keita
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Primary Examiner(s)Mathews, Alan A.
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Application NumberUS08/821,447Time in Patent Office1,012 DaysField of Search355/53, 356/399, 356/400, 356/401, 356/363, 250/491.1US Class Current355/53CPC Class CodesG03F 7/70591 Testing optical componentsG03F 7/70691 Handling of masks or workpi...G03F 9/70 for microlithography measur...
