A method of topography determination, the method including: obtaining a first focus value derived from a computational lithography model modeling patterning of an unpatterned substrate or derived from measurements of a patterned layer on an unpatterned substrate; obtaining a second focus value derived from measurement of a substrate having a topography; and determining a value of the topography from the first and second focus values.

Systems and methods for monitoring the focus of an EUV lithography system are disclosed. Another aspect includes a method having operations of measuring a first shift value for a first patterned set of sub-structures of a focus test structure on a wafer and measuring a second shift value for a second patterned set of sub-structures of the test structure on the wafer. The test structure may be formed on the wafer using asymmetric illumination, with the first patterned set of sub-structures having a first pitch and the second patterned set of sub-structures having a second pitch that is different from the first pitch. The method may further include determining a focus shift compensation for an illumination system based on a difference between the first shift value and the second shift value.

Disclosed are an amplitude monitoring system, a focusing and leveling apparatus and a defocus detection method. The defocus detection method comprises the steps of: adjusting amplitude of a scanning mirror (201) to a theoretical amplitude value and recording corresponding theoretical output voltage values of a photodetector (309) (S1); adjusting the amplitude of the scanning mirror (201) and sampling real-time amplitude values θi of the scanning mirror (201) and real-time output voltage values of the photodetector (309) to calculate compensated real-time demodulation results Si, and recording real-time defocus amounts Hi of a wafer table (305) (S2); subsequent to stepwise displacement of the wafer table (305), establishing a database based on the compensated real-time demodulation results Si and the real-time defocus amounts Hi of the wafer table (305) (S3); and in an actual measurement, sampling in real time an actual amplitude value θk of the scanning mirror (201) and actual output voltage values of the photodetector (309) to calculate a compensated real-time demodulation result Sk, and finding an actual defocus amount Hk of the wafer table (305) by searching the database using a linear interpolation method (S4). Such a focusing and leveling apparatus and defocus detection method avoid degraded stability of the scanning mirror due to long-time operation, which may lead to low wafer surface defocus measurement accuracy of the focusing and leveling apparatus.

A reticle for a semiconductor lithography process includes a glass plate having regions with a reduced optical transmission factor. The regions may include arrays of elements comprising defects such as cracks or voids which are formed by laser pulses. The regions may be adjacent to openings in an opaque material at the bottom of the reticle to shield the openings from a portion of the light which illuminates the reticle from the top. As a result, the light which exits the reticle and is used to pattern a substrate has an asymmetric intensity. This allows the substrate to be patterned with an inspection mark which indicates whether a defocus condition exists, and whether there is a positive or negative defocus condition. Related methods use a reticle to form a pattern on a substrate and for adjusting a focus condition using a reticle.

A method of metrology target design is described. The method includes determining a sensitivity of a parameter for a metrology target design to an optical aberration, determining the parameter for a product design exposed using an optical system of a lithographic apparatus, and determining an impact on the parameter of the metrology target design based on the parameter for the product design and the product of the sensitivity and one or more of the respective aberrations of the optical system.

Process window qualification (PWQ) layouts can be used to determine a presence of a pattern anomaly associated with the pattern, patterning process, or patterning apparatus. For example, a modulated die or field can be compared to a slightly lower offset modulated die or field. In another example, the high to low corners for a particular condition or combination of conditions are compared. In yet another example, process modulation parameters can be used to estimate criticality of particular weak points of interest.

A method for accurately obtaining a photolithography parameter. In the method, photolithography is performed on a target carrier with different preset photolithography parameters by using a same mask pattern as a mask, to obtain a plurality of target patterns. Each of the target pattern is compared with a standard pattern to obtain an evaluation value, and the target pattern is set as a valid pattern, when the evaluation value corresponding to the target pattern is greater than or equal to a preset value. A Bosung curve is drawn by taking a line width of the valid pattern and a preset photolithography parameter corresponding to the line width as data. The photolithography parameter corresponding to a preset line width is obtained according to the Bosung curve.

The present invention provides an exposure apparatus which performs a scanning exposure of each of a plurality of shot regions on a substrate, comprising a measuring device including a first detector configured to perform detection with respect to a measurement point on the substrate and a second detector configured to perform detection with respect to the measurement point prior to detection by the first detector, and configured to measure a height of the substrate based on an output from the first detector and an output from the second detector, and a processor configured to determine, based on measurement obtained based on an output from the first detector along with a scanning exposure of a first shot region, a first measurement point where the measuring device performs measurement first based on an output from the second detector with respect to a second shot region.

Disclosed is a method of determining a complex-valued field relating to a structure, comprising: obtaining image data relating to a series of images of the structure, for which at least one measurement parameter is varied over the series and obtaining a trained network operable to map a series of images to a corresponding complex-valued field. The method comprises inputting the image data into said trained network and non-iteratively determining the complex-valued field relating to the structure as the output of the trained network. A method of training the trained network is also disclosed.

A method of hot spot ranking for a patterning process. The method includes obtaining (i) a set of hot spots of a patterning process, (ii) measured values of one or more parameters of the patterning process corresponding to the set of hot spots, and (ii) simulated values of the one or more parameters of the patterning process corresponding to the set of hot spots; determining a measurement feedback based on the measured values and the simulated values of the one or more parameters of the patterning process; and determining, via simulation of a process model of the patterning process, a ranking of a hot spot within the set of hot spots based on the measurement feedback.