An exposure method includes acquiring first height information through detection of a height of an upper surface of a substrate subjected to exposure; acquiring first position information through detection of a relative position between the substrate and a first mask having a first pattern to be transferred on the substrate; converting the first height information to second position information; acquiring second height information through detection of a height of the upper surface of the substrate; acquiring third position information through detection of a relative position between the substrate and a second mask having a second pattern to be transferred on the substrate; converting the second height information to fourth position information; calculating differential position information, based on difference between the second position information and the fourth position information; and aligning the second mask and the substrate, based on the third position information and the differential position information.

Alignment features for an optical fibre assembly are formed directly into an ion trap chip to align an optical module with respect to the ion trap chip. This is achieved using microfabrication techniques to etch alignment elements into the surface of the ion trap chip, advantageously carried out with lithographic precision achieving the alignment accuracy required of the optical beam geometries for the application, with an alignment accuracy of a few micrometres. The alignment elements are advantageously etched along defined crystal planes of the silicon substrate of the chip. An external microstructure can be micromachined with lithographic precision to contain locating features that will fit, or “plug”, into the recesses of the chip, for instance ion microtrap chip.

Methods, metrology modules and target designs are provided, which improve the accuracy of metrology measurements. Methods provide flexible handling of multiple measurement recipes and setups and enable relating them to landscape features that indicate their relation to resonance regions and to flat regions. Clustering of recipes, self-consistency tests, common processing of aggregated measurements, noise reduction, cluster analysis, detailed analysis of the landscape and targets with skewed cells are employed separately or in combination to provide cumulative improvements of measurement accuracy.

A lithography system for generating grating structures is provided having a multiple column imaging system located on a bridge capable of moving in a cross-scan direction, a mask having a grating pattern with a fixed spatial frequency located in an object plane of the imaging system, a multiple line alignment mark aligned to the grating pattern and having a fixed spatial frequency, a platen configured to hold and scan a substrate, a scanning system configured to move the platen over a distance greater than a desired length of the grating pattern on the substrate, a longitudinal encoder scale attached to the platen and oriented in a scan direction and at least two encoder scales attached to the platen and arrayed in the cross-scan direction wherein the scales contain periodically spaced alignment marks having a fixed spatial frequency.

A method of maintaining a set of fingerprints representing variation of one or more process parameters across wafers subjected to a device manufacturing method, the method including: receiving measurement data of one or more parameters measured on wafers; updating the set of fingerprints based on an expected evolution of the one or more process parameters; and evaluation of the updated set of fingerprints based on decomposition of the received measurement data in terms of the updated set of fingerprints. Each fingerprint may have a stored likelihood of occurrence, and the decomposition may involve: estimating, based the received measurement data, likelihoods of occurrence of the set of fingerprints in the received measurement data; and updating the stored likelihoods of occurrence based on the estimated likelihoods.

Reducing an alignment error of an imprint lithography template with respect to a substrate includes locating central alignment marks of the template with respect to corresponding central alignment marks of the substrate and locating peripheral alignment marks of the template with respect to corresponding peripheral alignment marks of the substrate. In-plane alignment error of the template is assessed based on relative positions of central alignment marks of the template and corresponding central alignment marks of the substrate. A combined alignment error of the template is assessed based on relative positions of peripheral alignment marks of the template and corresponding peripheral alignment marks of the substrate. Out-of-plane alignment error of the template is assessed based on a difference between the-combined and the in-plane alignment error of the template, and a relative position of the template and the substrate is adjusted to reduce the out-of-plane alignment error of the template.

Embodiments described herein relate to a system, methods, and non-transitory computer-readable mediums that accurately align subsequent patterned layers in a photoresist utilizing a deep learning model and utilizing device patterns to replace alignment marks in lithography processes. The deep learning model is trained to recognize unique device patterns called alignment patterns in the FOV of the camera. Cameras in the lithography system capture images of the alignment patterns. The deep learning model finds the alignment patterns in the field of view of the cameras. An ideal image generated from a design file is matched with the camera with respect to the center of the field of view of the camera. A shift model and a rotation model are output from the deep learning model to create an alignment model. The alignment model is applied to the currently printing layer.

A method for manufacturing a structure on a substrate includes projecting an image of a reference pattern onto a substrate having a first patterned layer, the first patterned layer including first alignment marks and first overlay measurement marks, and the reference pattern including second alignment marks and second overlay measurement marks, aligning, based on the first alignment marks and the second alignment marks, the first patterned layer to the image of the reference pattern, obtaining a pre-overlay mapping of the first overlay measurement marks and the second overlay measurement marks, and determining compensation data indicative of information of the pre-overlay mapping of the first overlay measurement marks and the second overlay measurement marks.

A method includes receiving a wafer, measuring a surface topography of the wafer; calculating a topographical variation based on the surface topography measurement performing a single-zone alignment compensation when the topographical variation is less than a predetermined value or performing a multi-zone alignment compensation when the topographical variation is greater than the predetermined value; and performing a wafer alignment according to the single-zone alignment compensation or the multi-zone alignment compensation.

Systems and methods described herein relate to the manufacture of optical elements and optical systems. An example method includes overlaying a first mask on a photoresist material and a substrate, and causing a light source to illuminate the photoresist material through the first mask during a first exposure so as to define a first feature. During the first exposure, the light source is positioned at a non-normal angle with respect to a plane parallel to the substrate. The method includes developing the photoresist material so as to retain an elongate portion of the photoresist material on the substrate. A first end of the elongate portion includes an angled portion that is sloped at an angle with respect to a long axis of the elongate portion. The method also includes depositing a reflective material through a second mask onto the angled portion.