Patent application number | Description | Published |
20100284008 | Method of Determining Overlay Error and a Device Manufacturing Method - A method of determining an overlay error in which asymmetry of a first order of a diffraction pattern is modeled as being a weighted sum of harmonics. Both the first order harmonic and higher order harmonics are non-negligible and weights for both are calculated. The weights are calculated using three or more of sets of superimposed patterns using a least mean square method. | 11-11-2010 |
20110001978 | Inspection Method and Apparatus, Lithographic Apparatus, Lithographic Processing Cell and Device Manufacturing Method - A method of determining an overlay error between two successive layers produced by a lithographic process on a substrate, including using the lithographic process to form a calibration structure including a periodic structure of the same pitch on each of the layers, such that an overlaid pair of periodic structures is formed, the structures being parallel, but offset relative to each other by an overlay amount. A spectrum produced by directing a beam of radiation onto the calibration structure is measured and compared with one or more modeled spectra so as to determine values of the grating parameters for the calibration structure from the measured spectrum. The lithographic process is used to form further overlaid periodic structures on the same or one or more subsequent substrates, the determined grating parameter values for the calibration structure being used to determine overlay amounts for the further overlaid periodic structures. | 01-06-2011 |
20110020616 | Method of Determining Overlay Error and a Device Manufacturing Method - A method of determining an overlay error in a set of superimposed patterns. The patterns are divided into two and a first part of the pattern has a bias of d+s/2 between the first layer and second layer. A second part of the pattern has a bias of d−s/2 between the first and second layer. The two parts of the pattern are of equal size. To eliminate a particular harmonic s is chosen to be T/(2n) where T is the period of the pattern and n is a positive integer. | 01-27-2011 |
20110043791 | Metrology Method and Apparatus, Lithographic Apparatus, Device Manufacturing Method and Substrate - A metrology apparatus is arranged to illuminate a plurality of targets with an off-axis illumination mode. Images of the targets are obtained using only one first order diffracted beam. Where the target is a composite grating, overlay measurements can be obtained from the intensities of the images of the different gratings. Overlay measurements can be corrected for errors caused by variations in the position of the gratings in an image field. | 02-24-2011 |
20110178785 | Calibration Method and Apparatus - Calibration of an angularly resolved scatterometer is performed by measuring a target in two or more different arrangements. The different arrangements cause radiation being measured in an outgoing direction to be different combinations of radiation illuminating the target from ingoing directions. A reference mirror measurement may also be performed. The measurements and modeling of the difference between the first and second arrangements is used to estimate separately properties of the ingoing and outgoing optical systems. The modeling may account for symmetry of the respective periodic target. The modeling typically accounts for polarizing effects of the ingoing optical elements, the outgoing optical elements and the respective periodic target. The polarizing effects may be described in the modeling by Jones calculus or Mueller calculus. The modeling may include a parameterization in terms of basis functions such as Zernike polynomials. | 07-21-2011 |
20110194092 | Substrate, an Inspection Apparatus, and a Lithographic Apparatus - A target for measuring an overlay error or a critical dimension of a substrate comprises a grating. In one example, lines of the grating are arranged at an angle of about 45° with respect to edges of the target. As a consequence, the diffraction order of the grating reflection has its sub-maxima not aligned along the line on which the other diffraction orders are positioned, and overlap of intensity with other diffraction orders is reduced | 08-11-2011 |
20110304851 | Scatterometry Method and Measurement System for Lithography - 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 ( | 12-15-2011 |
20120123581 | Metrology Method and Inspection Apparatus, Lithographic System and Device Manufacturing Method - Methods are disclosed for measuring target structures formed by a lithographic process on a substrate. A grating structure within the target is smaller than an illumination spot and field of view of a measurement optical system. The optical system has a first branch leading to a pupil plane imaging sensor and a second branch leading to a substrate plane imaging sensor. A spatial light modulator is arranged in an intermediate pupil plane of the second branch of the optical system. The SLM imparts a programmable pattern of attenuation that may be used to correct for asymmetries between the first and second modes of illumination or imaging. By use of specific target designs and machine-learning processes, the attenuation patterns may also be programmed to act as filter functions, enhancing sensitivity to specific parameters of interest, such as focus. | 05-17-2012 |
20130010306 | Methods and Patterning Devices For Measuring Phase Aberration - A method of measuring a phase difference between two regions in an aberration function: Reference structures are produced on a substrate using illumination that minimizes effects of phase aberration. A grating is produced on the substrate using a phase-shift grating reticle to produce, in the exit pupil, a pair of diffracted non-zero orders, while forbidding other diffracted orders and produces interference fringes formed by interference between the pair. The interference contributes to a first grating on the substrate. Overlay error is measured between the grating and the reference structure using diffraction-based or image-based overlay measurements. A phase aberration function for the exit pupil of the lithographic apparatus can then be determined from the measured overlay errors. | 01-10-2013 |