A process of an extreme ultraviolet lithography is disclosed. The process includes receiving an extreme ultraviolet (EUV) mask, an EUV radiation source and an illuminator. The process also includes exposing the EUV mask by a radiation, originating from the EUV radiation source and directed by the illuminator, with a less-than-three-degree chief ray angle of incidence at the object side (CRAO). The process further includes removing most of the non-diffracted light and collecting and directing the diffracted light and the not removed non-diffracted light by a projection optics box (POB) to expose a target.

A method for reducing M3D effects on imaging is described. The method includes identifying points within a source plane of the photolithography system that are associated with pattern shifts resulting from diffraction of light off a photomask under an angle of incidence between an imaging beam of radiation and the mask normal, determining pattern shifts associated with the identified source plane points, and modifying the source to reduce the determined pattern shifts.

A method includes providing a photomask having a patterned absorption layer over a substrate. The photomask is irradiated with a beam having a mixture of transverse electronic (TE) waves and transverse magnetic (TM) waves. The irradiating includes generating surface plasmonic polaritons (SPP) on a sidewall of the patterned absorption layer. The SPP is used to suppress the TM waves while reflecting the TE waves. A target substrate is exposed to TE waves.

An integrated circuit includes a circuit area, and first and second scribe line portions. The first scribe line portion borders a first side of the circuit area, and the second scribe line portion borders a different second side of the circuit area. A plurality of dummy metal structures are located in the first and second scribe line portions, each of the dummy metal structures being located about at a lattice point of a same two-dimensional grid.

A metrology system is disclosed, in accordance with one or more embodiments of the present disclosure. The metrology system includes a stage configured to secure a sample, one or more diffraction-based overlay (DBO) metrology targets disposed on the sample. The metrology system includes a light source and one or more sensors. The metrology system includes a set of optics configured to direct illumination light from the light source to the one or more DBO metrology targets of the sample, the set of optics including a half-wave plate, the half-wave plate selectively insertable into an optical path such that the half-wave plate selectively passes both illumination light from an illumination channel and collection light from a collection channel, the half-wave plate being configured to selectively align an orientation of linearly polarized illumination light from the light source to an orientation of a grating of the one or more DBO metrology targets.

A model-based tuning method for tuning a first lithography system utilizing a reference lithography system, each of which has tunable parameters for controlling imaging performance. The method includes the steps of defining a test pattern and an imaging model; imaging the test pattern utilizing the reference lithography system and measuring the imaging results; imaging the test pattern utilizing the first lithography system and measuring the imaging results; calibrating the imaging model utilizing the imaging results corresponding to the reference lithography system, where the calibrated imaging model has a first set of parameter values; tuning the calibrated imaging model utilizing the imaging results corresponding to the first lithography system, where the tuned calibrated model has a second set of parameter values; and adjusting the parameters of the first lithography system based on a difference between the first set of parameter values and the second set of parameter values.

The present disclosure relates to an extreme ultraviolet lithography, EUVL, device comprising: a reticle comprising a lithographic pattern to be imaged on a target wafer; a light-transmissive pellicle membrane mounted in front of, and parallel to, the reticle, wherein the pellicle membrane scatters transmitted light along a scattering axis; and an extreme ultraviolet, EUV, illumination system configured to illuminate the reticle through the pellicle membrane, wherein an illumination distribution provided by the EUV illumination system is asymmetric as seen in a source-pupil plane of the EUV illumination system; wherein light reflected by the reticle and then transmitted through the pellicle membrane comprises a non-scattered fraction and a scattered fraction formed by light scattered by the pellicle membrane; the EUVL device further comprising: an imaging system having an acceptance cone configured to capture a portion of the light reflected by the reticle and then transmitted through the pellicle membrane.

A diffraction pattern guided source mask optimization (SMO) method that includes determining a source variable region from a diffraction pattern. The source variable region corresponds to one or more areas of a diffraction pattern in a pupil for which one or more pupil variables are to be adjusted. The source variable region in the diffraction pattern includes a plurality of pixels in an image of a selected region of interest in the diffraction pattern. Determining the source variable region can include binarization of the plurality of pixels in the image such that individual pixels are either included in the source variable region or excluded from the source variable region. The method can include adjusting the one or more pupil variables for the one or more areas of the pupil that correspond to the source variable region; and rendering a final pupil based on the adjusted one or more pupil variables.

A metrology system is disclosed, in accordance with one or more embodiments of the present disclosure. The metrology system includes a stage configured to secure a sample, one or more diffraction-based overlay (DBO) metrology targets disposed on the sample. The metrology system includes a light source and one or more sensors. The metrology system includes a set of optics configured to direct illumination light from the light source to the one or more DBO metrology targets of the sample, the set of optics including a half-wave plate, the half-wave plate selectively insertable into an optical path such that the half-wave plate selectively passes both illumination light from an illumination channel and collection light from a collection channel, the half-wave plate being configured to selectively align an orientation of linearly polarized illumination light from the light source to an orientation of a grating of the one or more DBO metrology targets.

Training methods and a mask correction method. One of the methods is for training a machine learning model configured to predict a post optical proximity correction (OPC) image for a mask. The method involves obtaining (i) a pre-OPC image associated with a design layout to be printed on a substrate, (ii) an image of one or more assist features for the mask associated with the design layout, and (iii) a reference post-OPC image of the design layout; and training the machine learning model using the pre-OPC image and the image of the one or more assist features as input such that a difference between the reference image and a predicted post-OPC image of the machine learning model is reduced.