摘要:
A level sensor for measuring a position of a surface of a substrate includes a projection unit including an emitter for emitting a radiation beam towards the substrate and a projection grating including a measurement grating and an aperture, such that the radiation beam incident on the projection grating is divided into a measurement radiation beam and a capture radiation beam. The level sensor further includes a detection unit including a first and second measurement detector, a first and second capture detector, a detection grating, and a first and second optical unit. The detection grating includes a ruled grating with multiple rules, which direct radiation towards the first and second measurement detector via the first and second optical unit, and a capture element directing radiation towards the first and second capture detector via the first and second optical unit.
摘要:
The invention provides a level sensor configured to determine a height level of a surface of a substrate supported on a movable substrate support, the level sensor including multiple projection units, multiple detection units, and a processing unit to calculate a height level for each of a plurality of measurement locations on the basis of the measurement beams from the projection units, wherein the level sensor is configured to measure height levels simultaneously at multiple measurement locations on the substrate, wherein the substrate support is configured to move the substrate in a first direction substantially parallel to the surface of the substrate to measure a height level at different locations on the substrate, and wherein at least part of the multiple measurement locations are at least spaced in a second direction that is substantially parallel to the surface of the substrate and perpendicular to the first direction.
摘要:
A method of determining a position of a substrate relative to an imprint template is described, wherein the imprint template has at least three gratings and the substrate has at least three gratings positioned such that each imprint template grating forms a composite grating with an associated substrate grating, the at least three imprint template gratings and associated substrate gratings having offsets relative to one another. The method includes detecting an intensity of radiation which is reflected by the three composite gratings, and using the detected intensities to determine displacement of the substrate or imprint template from a position.
摘要:
An angularly resolved scatterometer uses a broadband radiation source and an acousto-optical tunable filter to select one or more narrowband components from the broadband beam emitted by the source for use in measurements. A feedback loop can be used to control the intensity of the selected narrowband components to reduce noise.
摘要:
An imprint lithography template is provided with an alignment mark, wherein the alignment mark is formed from dielectric material having a refractive index which differs from the refractive index of the imprint lithography template, the dielectric material having a thickness which is such that it provides a phase difference between alignment radiation which has passed through the dielectric material and alignment radiation which has not passed through the dielectric material.
摘要:
In an aspect, an inspection method for detecting the presence or absence of a defect on an object, the object comprising a recess having a physical depth, is disclosed. The method includes directing radiation at the object, the radiation having a wavelength that is substantially equal to twice an optical depth of the recess, detecting radiation that is re-directed by the object or a defect on the object, and determining the presence or absence of a defect from the re-directed radiation.
摘要:
An inspection method is provided to determine a value related to a parameter of a target pattern printed on a substrate by a lithographic process used to manufacture a device layer on a substrate. The inspection method can include using an optical system with a high-NA objective lens, where the high-NA objective lens includes an object plane and a pupil plane. The inspection method can also include providing an aperture member to define at least one obscuration, determining a radial distance between a radially innermost point of each dark area and a nominal center of an image in a pupil plane, and determining an axial distance between the target and an object plane from the determined radial distance.
摘要:
A scatterometer has a radiation source capable of emitting radiation in distinct first and second wavelength ranges. An adjustable optical element is provided to effect a chromatic correction as necessary according to which wavelength range is in use. A single scatterometer can thereby effect measurements using widely separated wavelengths.
摘要:
A method for performing a tilted focus test includes the steps of providing a target object, providing a projection beam of radiation using a radiation source, providing a reflective device to introduce a projected projection beam of radiation onto the target portion, introducing a first projected projection beam of radiation onto the target object using the reflective device in a first orientation, using a tilting device for tilting the reflective device to a second orientation to provide a second projection beam with a tilt relative to said first projection beam, introducing a second projected projection beam of radiation onto the target object, and determining a lateral shift of the first and second projected projection beams on the target object and determining from said lateral shift a defocus of the target object with respect to the projected projection beam.
摘要:
In a method for determining a structure parameter of a target pattern, a first series of calibration spectra are determined from at least one reference pattern, each spectra being determined using a different known value of at least one structure parameter of the respective reference pattern. The first series of calibration spectra does not take into account parameters of an apparatus used to produce the reference pattern. A representation of each of the first series calibration spectra is stored in a central library. A second series of calibration spectra corresponding to at least one of the stored spectra for a target spectrum is determined using the parameters of the apparatus for measuring the target spectrum. A measured target spectrum is produced by directing a beam of radiation onto the target pattern. The measured target spectrum and the second series of calibration spectra are compared, where this comparison is used to derive a value for the structure parameter of the target pattern.