Charged-particle-beam microlithography systems that detect and offset beam-perturbing displacements of optical-column components
First Claim
1. A charged-particle-beam (CPB) microlithography system that selectively irradiates a charged particle beam onto a sensitive substrate to imprint a pattern on the substrate, the system comprising:
- a CPB-optical column situated upstream of the substrate and comprising a beam-position-control portion that deflects and resolves a charged particle beam for making a lithographic exposure of the pattern on the sensitive substrate;
at least one displacement sensor attached to a location in or on the CPB-optical column and configured to detect displacements, that could produce a beam-position error, of the location and to produce electrical signals corresponding to the detected displacements; and
a beam-corrector connected so as to receive the electrical signals from the at least one displacement sensor and to produce beam-correction signals corresponding to the electrical signals, the beam-correction signals being received by the beam-position-control portion which imparts a corresponding correction to the beam serving to correct the beam-position error.
1 Assignment
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Accused Products
Abstract
Charged-particle-beam (CPB) microlithography systems are disclosed that detect displacements of certain components and implement corrective countermeasures to the displacements so that pattern-exposure accuracy and precision are not compromised by the displacements. In an embodiment, displacement sensors and corrective actuators are installed at respective locations in or on the microlithography system. If the displacement sensors detect displacements at the respective locations, corresponding electrical signals produced by the sensors are fed-back or fed-forward to the corrective actuators. Alternatively, the electrical signals are routed directly to a beam-position-control system or routed indirectly to a displacement predictor. The displacement predictor calculates estimates of displacements based on data obtained previously concerning operation of certain displacement-generating components of the system. The estimates are used in feed-forward control of the beam position in the microlithography system, thereby improving pattern-transfer performance of the system.
9 Citations
71 Claims
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1. A charged-particle-beam (CPB) microlithography system that selectively irradiates a charged particle beam onto a sensitive substrate to imprint a pattern on the substrate, the system comprising:
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a CPB-optical column situated upstream of the substrate and comprising a beam-position-control portion that deflects and resolves a charged particle beam for making a lithographic exposure of the pattern on the sensitive substrate;
at least one displacement sensor attached to a location in or on the CPB-optical column and configured to detect displacements, that could produce a beam-position error, of the location and to produce electrical signals corresponding to the detected displacements; and
a beam-corrector connected so as to receive the electrical signals from the at least one displacement sensor and to produce beam-correction signals corresponding to the electrical signals, the beam-correction signals being received by the beam-position-control portion which imparts a corresponding correction to the beam serving to correct the beam-position error. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A charged-particle-beam (CPB) microlithography system that selectively irradiates a charged particle beam onto a sensitive substrate to imprint a pattern on the substrate, the system comprising:
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a CPB-optical system that includes a beam-position-control portion that controllably deflects and resolves a charged particle beam for making a lithographic exposure of the pattern on the sensitive substrate;
a stage situated relative to the CPB-optical system and configured to hold and controllably move a pattern-defining reticle or the substrate during the making of the lithographic exposure;
an interferometer situated relative to the stage and configured to determine a position of the stage;
at least one displacement sensor attached to a respective location on at least one of the stage and interferometer, the displacement sensor being configured to detect a displacement of the location, including a displacement producing a beam-position error that could degrade accuracy of the lithographic exposure, and to produce electrical signals corresponding to the detected displacement; and
a beam-corrector connected so as to receive the electrical signals from the at least one displacement sensor and to produce beam-correction signals corresponding to the electrical signals, the beam-correction signals being received by the beam-position-control portion which imparts a correction to the beam serving to correct the beam-position error. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34)
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35. A charged-particle-beam (CPB) microlithography system that selectively irradiates a charged particle beam onto a sensitive substrate to imprint a pattern on the substrate, the system comprising:
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a CPB-optical system that includes a beam-position-control portion that controllably deflects and resolves the charged particle beam for making a lithographic exposure of the pattern on the sensitive substrate;
a stage situated relative to the CPB-optical system and configured to hold and controllably move a pattern-defining reticle or the substrate during the making of the lithographic exposure;
an interferometer situated relative to the stage and configured to determine a position of the stage;
multiple displacement sensors attached to respective locations on the stage or interferometer, and on the CPB-optical system or beam-position-control portion, the displacement sensors being configured to detect a displacement of the respective location, including displacements that could produce a beam-position error that degrades accuracy of the lithographic exposure, and to produce respective electrical signals corresponding to the detected displacements; and
a beam-corrector connected so as to receive the electrical signals from the displacement sensors and to produce respective beam-correction signals that are routed to and received by the beam-position-control portion, which imparts a respective correction to the beam serving to correct the beam-position error. - View Dependent Claims (36, 37, 38, 39)
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40. A charged-particle-beam (CPB) microlithography system that selectively irradiates a charged particle beam onto a sensitive substrate to imprint a pattern on the substrate, the system comprising:
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a CPB-optical system, situated upstream of the substrate, comprising an optical column and a beam-position-control portion, the beam-position-control portion controllably deflecting and resolving a charged particle beam for making a lithographic exposure of the pattern on the sensitive substrate, the optical column comprising a vacuum chamber to which is connected a vacuum system;
a stage situated relative to the CPB-optical system and configured to hold a pattern-defining reticle or the substrate during the making of the lithographic exposure, the stage including a stage actuator configured to move the stage in a controlled manner;
multiple displacement sensors attached to respective locations, including the stage actuator and vacuum system, that tend to produce displacements, the displacement sensors being configured to detect the displacements at the respective locations, and to produce respective electrical signals corresponding to the detected respective displacements; and
a beam-corrector connected so as to receive the electrical signals from the displacement sensors, the beam-corrector comprising a predictor configured to calculate estimates of displacement of one or more of the optical column, the beam-position-control portion, the vacuum system, and the stage, and being configured to correct, based on the estimates provided by the predictor, the beam-position error by feed-forward control. - View Dependent Claims (41, 42)
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43. A charged-particle-beam (CPB) microlithography system that selectively irradiates a charged particle beam onto a sensitive substrate to imprint a pattern on the substrate, the system comprising:
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a CPB-optical system, comprising a beam-position-control portion and a vacuum chamber to which is connected a vacuum system, the beam-position-control portion controllably deflecting and resolving a charged particle beam for making a lithographic exposure of the pattern on the sensitive substrate;
a stage situated relative to the CPB-optical system and configured to hold a pattern-defining reticle or the substrate during the making of the lithographic exposure, the stage including a stage actuator configured to move the stage in a controlled manner;
a processor connected to the beam-position-control portion, the vacuum system, and the stage actuator and configured to produce, in a coordinated manner, respective drive signals for the beam-position-control portion, the vacuum system, and the stage actuator; and
a beam-corrector comprising a predictor configured to (i) receive the drive signals, (ii) calculate estimates of respective displacements caused by driving the beam-position-control portion, the vacuum system, and the stage, and (iii) calculate an expected beam-position error caused by the displacements, the beam-corrector being configured to correct the beam-position error by feed-forward control. - View Dependent Claims (44, 45)
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46. A charged-particle-beam (CPB) microlithography system that selectively irradiates a charged particle beam onto a sensitive substrate to imprint a pattern on the substrate, the system comprising:
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a CPB-optical system, situated upstream of the substrate, comprising an optical column and a beam-position-control portion, the beam-position-control portion being configured to deflect and resolve, in a controlled manner, a charged particle beam for making a lithographic exposure of the sensitive substrate;
multiple displacement sensors attached to respective locations on the optical column and the beam-position-control portion, and configured to detect displacements of the respective locations that could adversely impart a beam-position error and to produce electrical signals corresponding to the detected displacements; and
at least one damping actuator attached to the lens column or beam-position-control portion and configured to receive the electrical signals from the displacement sensors and to restrict, based on the signals, displacement of the optical column or beam-position-control portion. - View Dependent Claims (47, 48)
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49. A charged-particle-beam (CPB) microlithography system that selectively irradiates a charged particle beam onto a sensitive substrate to imprint a pattern on the substrate, the system comprising:
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a component that, when actuated, produces a displacement that, if unchecked, could produce an excessive beam-position error;
a displacement sensor attached to the component and configured to detect displacements of the component and to produce electrical signals corresponding to the detected displacements; and
a damping actuator attached to the component and connected to the displacement sensor so as to receive the electrical signals from the displacement sensor and being configured, when actuated, to attenuate the displacement of the component in a feed-forward manner. - View Dependent Claims (50, 51)
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52. A charged-particle-beam (CPB) microlithography system that selectively irradiates a charged particle beam onto a sensitive substrate to imprint a pattern on the substrate, the system comprising:
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a CPB-optical system, situated upstream of the substrate, comprising a beam-position-control portion that, when energized, controllably deflects and resolves the charged particle beam for making a lithographic exposure of the pattern on the sensitive substrate, the CPB-optical system being a part of an optical column to which a vacuum system is connected, the vacuum system being configured, when energized, to evacuate the optical column to a desired vacuum level;
a stage situated relative to the CPB-optical system and configured to hold, in the optical column, a pattern-defining reticle or the substrate during the making of the lithographic exposure, the stage including a stage actuator situated and configured, when energized, to move the stage in a controlled manner, wherein each of the optical column, the stage, and the beam-position-control portion being capable of producing, when energized, a respective beam-position error;
a controller connected to the beam-position-control portion, the vacuum system, and the stage actuator, the controller being configured to deliver respective drive signals to the beam-position-control portion, the vacuum system, and the stage actuator;
a predictor connected so as to receive the drive signals and configured to calculate estimates of respective displacements produced by the energized beam-position-control portion, the optical column, and the stage actuator; and
a respective damping actuator connected to at least one of the optical column, the beam-position-control portion, and the stage, the damping actuator being configured to restrict, in a feed-forward manner, the respective displacements based on the calculated estimates. - View Dependent Claims (53, 54)
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55. A charged-particle-beam (CPB) microlithography system that selectively irradiates a charged particle beam onto a sensitive substrate to imprint a pattern on the substrate, the system comprising:
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a CPB-optical system, situated upstream of the substrate, comprising a CPB-optical column and a beam-position-control portion, the beam-position-control portion being configured to deflect and resolve the charged particle beam in a controlled manner for making a lithographic exposure of the pattern on the sensitive substrate; and
at least one displacement damper attached to the CPB-optical column or the beam-position-control portion and configured, when energized, to dampen displacements of the CPB-optical column or beam-position-control portion, respectively. - View Dependent Claims (56)
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57. In a charged-particle-beam (CPB) microlithography method in which a pattern is selectively irradiated, by a charged particle beam passing through a CPB-optical column, onto a sensitive substrate so as to imprint the pattern on the substrate, a method for reducing a beam-position error accompanying a displacement of a location in or on the CPB-optical column, the method comprising:
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detecting a displacement of the location; and
based on and in response to the displacement, imparting a corrective shift in a component of the CPB-optical system, the corrective shift serving at least to reduce the beam-position error. - View Dependent Claims (58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71)
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Specification