The present description concerns a method that includes the compression, by a processor, of an image comprising first patterns by transforming the image into a first representation formed of two-point elements. The method also includes the execution, by a neural network, of an inference operation on the first representation to generate a second representation formed of two-point elements. The method further includes the generation of a lithographic mask based on the decompression of the second representation.

In some aspects, an integrated model accounts for effects from both the mask fabrication process and the wafer lithography process. The aerial image incident on the wafer, the pattern printed on the wafer, and/or measures of the foregoing are estimated using an integrated three-dimensional mask (M3D) model, as follows. The shapes in the mask fabrication description are partitioned into feature images. Each feature image is convolved with a corresponding M3D filter. The M3D filter represents an electromagnetic scattering effect of that feature image in the wafer lithography process, and the feature image and/or M3D filter account for effects on the layout geometry from the mask fabrication process. This is done without estimating the mask pattern printed on the lithographic mask. The mask fabrication description is modified based on differences between the estimated lithography results and corresponding target results.

In some aspects, an integrated model accounts for effects from both the mask fabrication process and the wafer lithography process. The aerial image incident on the wafer, the pattern printed on the wafer, and/or measures of the foregoing are estimated using an integrated three-dimensional mask (M3D) model, as follows. The shapes in the mask fabrication description are partitioned into feature images. Each feature image is convolved with a corresponding M3D filter. The M3D filter represents an electromagnetic scattering effect of that feature image in the wafer lithography process, and the feature image and/or M3D filter account for effects on the layout geometry from the mask fabrication process. This is done without estimating the mask pattern printed on the lithographic mask. The mask fabrication description is modified based on differences between the estimated lithography results and corresponding target results.

The present disclosure describes a method of patterning a semiconductor wafer using extreme ultraviolet lithography (EUVL). The method includes receiving an EUVL mask that includes a substrate having a low temperature expansion material, a reflective multilayer over the substrate, a capping layer over the reflective multilayer, and an absorber layer over the capping layer. The method further includes patterning the absorber layer to form a trench on the EUVL mask, wherein the trench has a first width above a target width. The method further includes treating the EUVL mask with oxygen plasma to reduce the trench to a second width, wherein the second width is below the target width. The method may also include treating the EUVL mask with nitrogen plasma to protect the capping layer, wherein the treating of the EUVL mask with the nitrogen plasma expands the trench to a third width at the target width.

The present disclosure describes a method of patterning a semiconductor wafer using extreme ultraviolet lithography (EUVL). The method includes receiving an EUVL mask that includes a substrate having a low temperature expansion material, a reflective multilayer over the substrate, a capping layer over the reflective multilayer, and an absorber layer over the capping layer. The method further includes patterning the absorber layer to form a trench on the EUVL mask, wherein the trench has a first width above a target width. The method further includes treating the EUVL mask with oxygen plasma to reduce the trench to a second width, wherein the second width is below the target width. The method may also include treating the EUVL mask with nitrogen plasma to protect the capping layer, wherein the treating of the EUVL mask with the nitrogen plasma expands the trench to a third width at the target width.

Aspects described herein relate to obtaining a mask pattern using a cost function gradient (CFG) generated from a Jacobian matrix generated from a perturbation look-up table (PLT). In an example method, a PLT is populated (108). Each table entry of the PLT is based on a respective perturbed intensity signal. The respective perturbed intensity signal is based on a simulated signal received at an image surface using a mask pattern having a perturbed element of the mask pattern. The mask pattern is for a design of an integrated circuit. A matrix is populated (110) using the PLT and a target intensity signal. The target intensity signal is based on a signal received at the image surface to form target features at the image surface. A CFG is defined (112) based on the matrix. An analysis is performed (114) on the mask pattern based on the CFG.

Aspects described herein relate to obtaining a mask pattern using a cost function gradient (CFG) generated from a Jacobian matrix generated from a perturbation look-up table (PLT). In an example method, a PLT is populated (108). Each table entry of the PLT is based on a respective perturbed intensity signal. The respective perturbed intensity signal is based on a simulated signal received at an image surface using a mask pattern having a perturbed element of the mask pattern. The mask pattern is for a design of an integrated circuit. A matrix is populated (110) using the PLT and a target intensity signal. The target intensity signal is based on a signal received at the image surface to form target features at the image surface. A CFG is defined (112) based on the matrix. An analysis is performed (114) on the mask pattern based on the CFG.

A method comprises receiving an integrated circuit (IC) chip design, and generating, by one or more processors and based on the IC chip design, dose information, a wafer image, and a wafer target. Further, the method comprises modifying, by the one or more processors, the dose information based on a comparison of the wafer image and the wafer target. Further, the method comprises outputting the modified dose information to a mask writing device.

A method comprises receiving an integrated circuit (IC) chip design, and generating, by one or more processors and based on the IC chip design, dose information, a wafer image, and a wafer target. Further, the method comprises modifying, by the one or more processors, the dose information based on a comparison of the wafer image and the wafer target. Further, the method comprises outputting the modified dose information to a mask writing device.

A first set of critical dimension (CD) measurements of resist patterns created by a lithography process and a second set of CD measurements of water patterns created by an etch process may be obtained. A forward etch model and an inverse etch model may be calibrated together by reducing (1) a first prediction error between the second set of CD measurements and a first set of simulated CDs predicted by the forward etch model based on the resist patterns, a second prediction error between the first set of CD measurements and a second set of simulated CDs predicted by the inverse etch model based on the wafer patterns, and a matching error between the forward etch model and the inverse etch model.