A method includes forming a first photo resist layer over a base structure and a target feature over the base structure, performing an un-patterned exposure on the first photo resist layer, and developing the first photo resist layer. After the step of developing, a corner portion of the first photo resist layer remains at a corner between a top surface of the base structure and an edge of the target feature. A second photo resist layer is formed over the target feature, the base structure, and the corner portion of the first photo resist layer. The second photo resist layer is exposed using a patterned lithography mask. The second photo resist layer is patterned to form a patterned photo resist.

An inspection apparatus includes an inspection optical system configured to a direct an inspection beam onto a surface of a substrate, the inspection optical system having an objective, a focus measurement optical system configured to receive a focus measurement beam, redirected by the substrate, from the objective, the focus measurement optical system having a movable reflective element configured to receive the focus measurement beam, and a control system configured to cause movement of the reflective element with a direction component along a beam path of the focus measurement beam and configured to determine whether the substrate surface is in the focus of the objective based on the focus measurement beam.

The present invention concerns a method for producing a volume object by lithography, comprising a projection of the projection image onto a plane to be illuminated of the layer of material, which involves: moving the mask in a movement having a component along an oblique axis forming an angle with the plane to be illuminated, and transforming a movement of the mask having a component along the oblique axis forming the angle with the plane to be illuminated into a displacement of the projection image on the plane to be illuminated along the first direction of the displacement contained in the plane to be illuminated by means of a mirror that reflects the projection image coming from the mask towards the plane to be illuminated.

This invention relates to a method of obtaining optimal focus for exposing a photoresist in an EUV lithography with an EUV mask containing a pattern with an assist feature. The invention also relates to an EUV mask with a special focus test target for monitoring focus in EUV lithography, and a method of fabricating this EUV mask by designing the special focus test target. The EUV mask contains a repeating pattern, wherein the repeating pattern has two different pitches, i.e. a first pitch and a second pitch, and contains an assist feature between main features. Because the two different pitches have different focus offsets, the difference between linewidths of said gratings provides a calibration curve which is a measure of focus. The method for monitoring focus is performing an EUV exposure using a focus position with a pre-determined focus position as calibrated using the linewidth difference between the two gratings. The EUV mask for monitoring focus of present invention is applicable to both test and product masks.

An object of the present invention is to provide a fabrication method for pattern-formed structure having a smooth three-dimensional structure through a fewer processes. To achieve the object, the present invention provides a fabrication method for pattern-formed structure comprising: a dot modulation pattern forming process of binarizing a shape of a targeted three-dimensional structure to form a dot modulation pattern, a writing process of using the dot modulation pattern to write directly by a writer on a photosensitive resin layer formed on a substrate, and a developing process of developing the photosensitive resin layer after the writing to form a resin layer with three-dimensional structure, wherein the writing process is performed by a writing energy supplying method in which writing energy is supplied to the photosensitive resin layer by an area larger than a minimum dot area in the dot modulation pattern.