Synopsys, Inc.

Qiaolin Zhang

Hua Song

Qiliang Yan

James Patrick Shiely

Haiqing Wei

Yongfa Fan

Cheng En Wu

Laurent Depre

Bradley J Falch

Paul VanAdrichem

A computer-implemented method includes modeling, using the computer, a photoresist profile in accordance with a magnitude of a gradient of an inhibitor concentration disposed in the photoresist. The photoresist is used during a process to form an integrated circuit. In one embodiment, the computer-implemented method further includes applying the modeled photoresist profile to reduce a distortion in a printed photoresist pattern caused by a response of the photoresist to an electromagnetic wave and/or particle beam during the process.

Method for modeling a photoresist profile

One embodiment of the present invention provides a system that accurately models polarization states of an illumination source in an optical lithography system for manufacturing integrated circuits. During operation, the system starts by receiving a two-dimensional (2D) grid map for an illumination source pupil in the optical lithography system. The system then constructs a source-polarization model for the illumination source by defining a polarization state at each grid point in the grid map. Next, the system enhances a lithography model for the optical lithography system by incorporating the source-polarization model into the lithography/OPC model.

Modeling an arbitrarily polarized illumination source in an optical lithography system

One embodiment of the present invention provides a system that determines image intensity at a location in a photoresist (PR) layer on a wafer. During operation, the system receives a set of masks which were used to generate one or more patterned layers of a multilayer structure on the wafer, wherein a patterned layer includes a set of reflectors on a top surface of the patterned layer, which correspond to patterns in a patterned-layer mask in the set of masks, wherein a reflector reflects light from a light source during a photolithography process. The system then generates a first virtual mask based on the first mask and the patterned-layer mask, wherein the first virtual mask uses a clear area to model a reflector in the set of reflectors. Next, the system determines the image intensity value at the location on the PR layer based at least on the first mask and the first virtual mask.

Modeling thin-film stack topography effect on a photolithography process

One embodiment of the present invention relates to a process that models critical-dimension (CD) scanning-electron-microscopy (CD-SEM) extraction during photolithography process model calibration. During operation, the process receives measured CD values which were obtained using a CD-SEM extraction process, wherein the CD-SEM extraction process determines a measured CD value for a feature by measuring multiple CD values of the feature along multiple electron beam scans. The process then determines simulated CD values, wherein a simulated CD value is determined based at least on a set of CD extraction cut-lines evenly placed around the target feature. During subsequent photolithography process model calibration, the process fits a parameter that models an aspect of the photolithography process based at least on both the measured CD values and the simulated CD values.

Modeling critical-dimension (CD) scanning-electron-microscopy (CD-SEM) CD extraction

A method is described herein for predicting lateral position information about a feature represented in an integrated circuit layout for use with an integrated circuit fabrication process, where the process projects an image onto a resist. The method includes providing a lateral distribution of intensity values of the image at different depths with the resist. Next, the lateral position of an edge point of the feature is predicted in dependence upon a particular resist development time, and further in dependence upon the image intensity values at more than one depth within the resist.

Bulk image modeling for optical proximity correction

One embodiment of the present invention provides a system that accurately predicts an apodization effect in an optical lithography system for manufacturing an integrated circuit. During operation, the system starts by collecting an apodization-effect-induced spatial transmission profile from the optical lithography system. The system then constructs an apodization model based on the spatial transmission profile. Next, the system enhances a lithography model for the optical lithography system by incorporating the apodization model into the lithography model, wherein the enhanced lithography model accurately predicts the effects of apodization on the optical lithography system.

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Mountain View, CA, United States of America

Qiaolin Zhang