Disclosed is an inspection apparatus for use in lithography. It comprises a support for a substrate carrying a plurality of metrology targets; an optical system for illuminating the targets under predetermined illumination conditions and for detecting predetermined portions of radiation diffracted by the targets under the illumination conditions; a processor arranged to calculate from said detected portions of diffracted radiation a measurement of asymmetry for a specific target; and a controller for causing the optical system and processor to measure asymmetry in at least two of said targets which have different known components of positional offset between structures and smaller sub-structures within a layer on the substrate and calculate from the results of said asymmetry measurements a measurement of a performance parameter of the lithographic process for structures of said smaller size. Also disclosed are substrates provided with a plurality of novel metrology targets formed by a lithographic process.

In a charged-particle lithography apparatus, during writing a desired pattern, the duration of exposure slots is adapted to compensate for fluctuations of the particle beam. In the writing process the aperture images are mutually overlapping on the target so each pixel is exposed through a number of aperture images overlapping at the respective pixel, which results in an exposure of the respective pixel through an effective pixel exposure time, i.e., the sum of durations of contributing exposure slots, and the exposure slot durations are adjusted by: (i) determining a desired duration of the effective pixel exposure time for the pixels, as a function of the time of exposure of the pixels, (ii) determining contributing exposure slots for the pixels, (iii) calculating durations for the contributing exposure slots thus determined such that the sum of the durations over said contributing exposure slots is an actual effective exposure time which approximates said desired duration of the effective pixel exposure time.

The durations in step (iii) are calculated in accordance with a predetermined set of allowed durations, wherein at least one of the durations thus calculated is different from the other durations selected for said set of exposure slots

In a charged-particle lithography apparatus, during writing a desired pattern, the duration of exposure slots is adapted to compensate for fluctuations of the particle beam. In the writing process the aperture images are mutually overlapping on the target so each pixel is exposed through a number of aperture images overlapping at the respective pixel, which results in an exposure of the respective pixel through an effective pixel exposure time, i.e., the sum of durations of contributing exposure slots, and the exposure slot durations are adjusted by: (i) determining a desired duration of the effective pixel exposure time for the pixels, as a function of the time of exposure of the pixels, (ii) determining contributing exposure slots for the pixels, (iii) calculating durations for the contributing exposure slots thus determined such that the sum of the durations over said contributing exposure slots is an actual effective exposure time which approximates said desired duration of the effective pixel exposure time.

The durations in step (iii) are calculated in accordance with a predetermined set of allowed durations, wherein at least one of the durations thus calculated is different from the other durations selected for said set of exposure slots

Disclosed is an inspection apparatus for use in lithography. It comprises a support for a substrate carrying a plurality of metrology targets; an optical system for illuminating the targets under predetermined illumination conditions and for detecting predetermined portions of radiation diffracted by the targets under the illumination conditions; a processor arranged to calculate from said detected portions of diffracted radiation a measurement of asymmetry for a specific target; and a controller for causing the optical system and processor to measure asymmetry in at least two of said targets which have different known components of positional offset between structures and smaller sub-structures within a layer on the substrate and calculate from the results of said asymmetry measurements a measurement of a performance parameter of the lithographic process for structures of said smaller size. Also disclosed are substrates provided with a plurality of novel metrology targets formed by a lithographic process.

Disclosed is an inspection apparatus for use in lithography. It comprises a support for a substrate carrying a plurality of metrology targets; an optical system for illuminating the targets under predetermined illumination conditions and for detecting predetermined portions of radiation diffracted by the targets under the illumination conditions; a processor arranged to calculate from said detected portions of diffracted radiation a measurement of asymmetry for a specific target; and a controller for causing the optical system and processor to measure asymmetry in at least two of said targets which have different known components of positional offset between structures and smaller sub-structures within a layer on the substrate and calculate from the results of said asymmetry measurements a measurement of a performance parameter of the lithographic process for structures of said smaller size. Also disclosed are substrates provided with a plurality of novel metrology targets formed by a lithographic process.

Embodiments described herein provide a method of large area lithography. One embodiment of the method includes projecting at least one incident beam to a mask in a propagation direction of the at least one incident beam. The mask having at least one period of a dispersive element that diffracts the incident beam into order mode beams having one or more diffraction orders with a highest order N greater than 1. The one or more diffraction orders provide an intensity pattern in a medium between the mask and a substrate having a photoresist layer disposed thereon. The intensity pattern includes a plurality of intensity peaks defined by sub-periodic patterns of the at least one period. The intensity peaks write a plurality of portions in the photoresist layer such that a number of the portions in the photoresist layer corresponding to the at least one period is greater than N.

Embodiments described herein provide a method of large area lithography. One embodiment of the method includes projecting at least one incident beam to a mask in a propagation direction of the at least one incident beam. The mask having at least one period of a dispersive element that diffracts the incident beam into order mode beams having one or more diffraction orders with a highest order N greater than 1. The one or more diffraction orders provide an intensity pattern in a medium between the mask and a substrate having a photoresist layer disposed thereon. The intensity pattern includes a plurality of intensity peaks defined by sub-periodic patterns of the at least one period. The intensity peaks write a plurality of portions in the photoresist layer such that a number of the portions in the photoresist layer corresponding to the at least one period is greater than N.

A method of manufacturing a mask includes attaching a first mask base substrate and a second mask base substrate to opposite sides of an adhesive layer, forming a photoresist layer on the first and second mask base substrates, exposing and developing the photoresist layer to remove the photoresist layer on effective area at centers of surfaces of the first and second mask base substrates such that the first photoresist layer remains on non-effective areas at edges of surfaces of the first mask base substrate and the second mask base substrate, etching the effective area to form a stepped groove on the first and second mask base substrates, separating the first and second mask base substrates from the adhesive layer, and forming a pattern hole in the effective area of first and second mask base substrates, each with the first stepped groove thereon.

A method of manufacturing a mask includes attaching a first mask base substrate and a second mask base substrate to opposite sides of an adhesive layer, forming a photoresist layer on the first and second mask base substrates, exposing and developing the photoresist layer to remove the photoresist layer on effective area at centers of surfaces of the first and second mask base substrates such that the first photoresist layer remains on non-effective areas at edges of surfaces of the first mask base substrate and the second mask base substrate, etching the effective area to form a stepped groove on the first and second mask base substrates, separating the first and second mask base substrates from the adhesive layer, and forming a pattern hole in the effective area of first and second mask base substrates, each with the first stepped groove thereon.

The present application provides a method for adjusting the local thickness of a photoresist, and a semiconductor front layer structure. The thickness of the photoresist layer in a first region of the stack structure is more than the thickness of the photoresist layer in a second region. The photomask is configured to include an auxiliary pattern for exposing the first region and another pattern for exposing the second region. The first region and the second region of the photoresist layer are exposed simultaneously by one photomask. The exposure intensity is adjusted so that part of the surface of the first region is dissolved during the development, the auxiliary pattern is not transferred to the photoresist layer in the first region, resulting in decreased thickness of the photoresist layer in the first region after development. After development, the other pattern is transferred to the photoresist layer in the second region.