摘要:
Disclosed are methods, apparatuses, and lithographic systems for calibrating an inspection apparatus. Radiation is projected onto a pattern in a target position of a substrate. By making a plurality of measurements of the pattern and comparing the measured first or higher diffraction orders of radiation reflected from the pattern of different measurements, a residual error indicative of the error in a scatterometer may be calculated. This error is an error in measurements of substrate parameters caused by irregularities of the scatterometer. The residual error may manifest itself as an asymmetry in the diffraction spectra.
摘要:
In order to determine whether an exposure apparatus is outputting the correct dose of radiation and its projection system is focusing the radiation correctly, a test pattern is used on a mask for printing a specific marker onto a substrate. This marker is then measured by an inspection apparatus, such as a scatterometer, to determine whether there are errors in focus and dose and other related properties. The test pattern is configured such that changes in focus and dose may be easily determined by measuring the properties of a pattern that is exposed using the mask. The test pattern may be a 2D pattern where physical or geometric properties, e.g., pitch, are different in each of the two dimensions. The test pattern may also be a one-dimensional pattern made up of an array of structures in one dimension, the structures being made up of at least one substructure, the substructures reacting differently to focus and dose and giving rise to an exposed pattern from which focus and dose may be determined.
摘要:
A method is used to determine focus of a lithographic apparatus used in a lithographic process on a substrate. The lithographic process is used to form at least two periodic structures on the substrate. Each structure has at least one feature that has an asymmetry between opposing side wall angles that varies as a different function of the focus of the lithographic apparatus on the substrate. A spectrum produced by directing a beam of radiation onto the at least two periodic structures is measured and ratios of the asymmetries are determined. The ratios and a relationship between the focus and the side wall asymmetry for each structure is used to determine the focus of the lithographic apparatus on the substrate.
摘要:
Scatterometry method and apparatus are useful in a lithographic apparatus and device manufacturing. A back focal plane diffraction intensity image of a measurement projection system configured to project a radiation beam onto a target portion of a substrate is measured. A beam of radiation having a first wavelength is directed to the substrate. A diffraction image of a zeroth diffraction order and higher order diffraction from a diffraction structure in the substrate is provided. A first layer (4) of the diffractionstructure provides a diffraction image having only a zeroth diffraction order. A second layer (5) has a periodic structure (6a, 6b) configured such that a lowest spatial frequency of the periodic structure is lower than spatial frequencies of interest of the first structure. From the diffraction image originating from diffraction of the radiation beam in both the first and second layer a critical dimension metrology parameter is determined.
摘要:
Scatterometry method and apparatus are useful in a lithographic apparatus and device manufacturing. A back focal plane diffraction intensity image of a measurement projection system configured to project a radiation beam onto a target portion of a substrate is measured. A beam of radiation having a first wavelength is directed to the substrate. A diffraction image of a zeroth diffraction order and higher order diffraction from a diffraction structure in the substrate is provided. A first layer (4) of the diffractionstructure provides a diffraction image having only a zeroth diffraction order. A second layer (5) has a periodic structure (6a, 6b) configured such that a lowest spatial frequency of the periodic structure is lower than spatial frequencies of interest of the first structure. From the diffraction image originating from diffraction of the radiation beam in both the first and second layer a critical dimension metrology parameter is determined.
摘要:
In order to determine whether an exposure apparatus is outputting the correct dose of radiation and a projection system of the exposure apparatus is focusing the radiation correctly, a test pattern is used on a mask for printing a specific marker onto a substrate. This marker may be measured by an inspection apparatus, such as, for example, a scatterometer to determine whether errors in focus, dose, and other related properties are present. The test pattern is arranged such that changes in focus and dose may be easily determined by measuring properties of a pattern that is exposed using the mask. The test pattern of the mask is arranged so that it gives rise to a marker pattern on the substrate surface. The marker pattern contains structures that have at least two measurable side wall angles. Asymmetry between side wall angles of a structure is related to focus (or defocus) of the exposure radiation from the exposure apparatus. The extent of defocus may thereby be determined by measuring an asymmetry in side wall angle of the printed marker pattern structures.
摘要:
A method of assessing a model of a substrate is presented. A scatterometry measurement is taken using radiation at a first wavelength. The wavelength of the radiation is then changed and a further scatterometry measurement taken. If the scatterometry measurements are consistent across a range of wavelengths then the model is sufficiently accurate. However, if the scatterometry measurements change as the wavelength changes then the model of the substrate is not sufficiently accurate.
摘要:
A communication circuit (10) and method updates an active link set list (50) in an asynchronous wireless communication system. In one embodiment, the communication circuit (10) may be a wireless device (600) or any other suitable communication device. The communication circuit (10) includes candidate reference link determination circuitry (30) to receive an active link set update message (60) and in response, to create the candidate list of reference links (20) from the active link set list (50). The candidate reference link determination circuitry (30) creates the candidate list of reference links based on, for example, an indication in the received active link set update message (60) to retain links from the active link set list (50).
摘要:
The present invention provides a method for forming a substrate for use in calibrating a metrology tool in order to compensate for orientation-dependent variations within the metrology tool.
摘要:
A method of matching CD-SEM's to ensure consistent measurements over an installed base of SEM's is disclosed by measuring with each of a plurality of scanning electron microscopes the feature size of resist features in at least two positions on the substrate such that field-to-field variations, and reticle and exposure tool non-uniformities are efficiently suppressed in the matching result.