Asml Masktools B.v.

National Semiconductor Corporation

Asml Holding N.v.

Asml Masktools Netherlands B.v.

Asml Masktooks B.v.

Xuelong Shi

Jang Fung Chen

Douglas Van Den Broeke

Kurt E Wampler

Thomas Laidig

Duan-Fu Stephen Hsu

Robert John Socha

Uwe Hollerbach

Stephen Hsu

Ralph Schlief

Michael Hsu

A method of determining calibration test patterns to be utilized to calibrate a model for simulating the imaging performance of an optical imaging system. The method includes the steps of defining design rules associated with a given imaging process; defining a model equation representing the imaging performance of the optical imaging system; determining a boundary of an imaging signal space based on the design rules; selecting calibration patterns based on the boundary of the imaging signal space such that the calibration patterns are on the boundary or within the boundary of the imaging signal space; and storing the selected calibration test patterns, where the calibration test patterns are utilized to calibrate the model for simulating the imaging performance of the optical imaging system.

Method, program product and apparatus for translating geometrical design rules into boundary conditions in the imaging space so as to define test patterns for use in optical model calibration

A method for generating a photolithography mask for optically transferring a pattern formed in the mask onto a substrate utilizing an imaging system. The method includes the steps of: (a) defining a set of calibration patterns, which are represented in a data format; (b) printing the calibration patterns on a substrate utilizing the given imaging system; (c) determining a first set of contour patterns corresponding to the calibration patterns imaged on the substrate; (d) generating a system pseudo-intensity function, which approximates the imaging performance of the imaging system; (e) determining a second set of contour patterns by utilizing the system pseudo-intensity function to define how the calibration patterns will be imaged in the substrate; (f) comparing the first set of contour patterns and the second set of contour patterns to determine the difference therebetween; (g) adjusting the system pseudo-intensity function until the difference between the first set of contour patterns and the second set of contour patterns is below a predefined criteria; and (h) utilizing the adjusted system pseudo-intensity function to modify the mask so as to provide for optical proximity correction.

Method of two dimensional feature model calibration and optimization

Optical proximity effects (OPEs) are a well-known phenomenon in photolithography. OPEs result from the structural interaction between the main feature and neighboring features. It has been determined by the present inventors that such structural interactions not only affect the critical dimension of the main feature at the image plane, but also the process latitude of the main feature. Moreover, it has been determined that the variation of the critical dimension as well as the process latitude of the main feature is a direct consequence of light field interference between the main feature and the neighboring features. Depending on the phase of the field produced by the neighboring features, the main feature critical dimension and process latitude can be improved by constructive light field interference, or degraded by destructive light field interference. The phase of the field produced by the neighboring features is dependent on the pitch as well as the illumination angle. For a given illumination, the forbidden pitch region is the location where the field produced by the neighboring features interferes with the field of the main feature destructively. The present invention provides a method for determining and eliminating the forbidden pitch region for any feature size and illumination condition. Moreover, it provides a method for performing illumination design in order to suppress the forbidden pitch phenomena, and for optimal placement of scattering bar assist features.

Method of identifying an extreme interaction pitch region, methods of designing mask patterns and manufacturing masks, device manufacturing methods and computer programs

Disclosed concepts include a method of optimizing an illumination profile of a pattern to be formed in a surface of a substrate. Illumination is optimized by defining a transmission cross coefficient ('TCC') function determined in accordance with an illumination pupil and a projection pupil corresponding to an illuminator, representing at least one resolvable feature of a mask to be printed on the substrate by at least one impulse function, and creating an interference map of a predetermined order based on the at least one impulse function and the TCC function, wherein the interference map represents the at least one resolvable feature to be printed on the substrate and areas of destructive interference.

Method of optical proximity correction design for contact hole mask

A method of generating a mask design having optical proximity correction features disposed therein. The methods includes the steps of obtaining a desired target pattern having features to be imaged on a substrate; determining a first interference map based on the target pattern, which defines areas of constructive interference between at least one of the features to be imaged and a field area adjacent the at least one feature; placing a first set of assist features having a first phase in the mask design based on the areas of constructive interference defined by the first interference map; determining a second interference map based on the first set of assist features, which defines areas of constructive interference between assist features of the first set of assist features and a field area adjacent at least one of the assist features of the first set of assist features; and placing a second set of assist features having a second phase in the mask design based on the areas of constructive interference defined by the second interference map, wherein the first phase does not equal the second phase.

Method and apparatus for performing model based placement of phase-balanced scattering bars for sub-wavelength optical lithography

A method of generating a mask for use in a photolithography process. The method includes the steps of determining a target mask pattern having a plurality of features to be imaged and an illumination system to be utilized to image the mask; identifying a critical pitch within the target pattern and optimizing illumination settings of the illumination system for imaging the critical pitch; identifying a forbidden pitch within the target pattern; and modifying the transmittance of the features having a pitch equal to or substantially equal to the forbidden pitch such that the exposure latitude of the features equal to or substantially equal to the forbidden pitch is increased.

Method for performing transmission tuning of a mask pattern to improve process latitude

Disclosed concepts include a method of, and program product for, optimizing an illumination profile of a pattern to be formed in a surface of a substrate relative to a given mask. Steps include mathematically representing resolvable feature(s) from the given mask, generating an interference map representation from the previous step, modifying the interference map representation to maximize intensity corresponding to the resolvable features, and determining assist feature size(s) such that intensity side lobes do not print.

Feature optimization using interference mapping lithography

A method for generating models for simulating the imaging performance of a plurality of exposure tools. The method includes the steps of: generating a calibrated model for a first exposure tool capable of estimating an image to be produced by the first exposure tool for a given photolithography process, where the calibrated model includes a first set of basis functions; generating a model of a second exposure tool capable of estimating an image to be produced by the second exposure tool for the photolithography process, where the model includes a second set of basis functions; and representing the second set of basis functions as a linear combination of the first set of basis functions so as to generate an equivalent model function corresponding to the second exposure tool, where the equivalent model function produces a simulated image corresponding to the image generated by the second exposure tool for the photolithography process.

Method of predicting and minimizing model OPC deviation due to mix/match of exposure tools using a calibrated eigen decomposition model

A method of generating a mask for use in an imaging process pattern. The method includes the steps of: (a) obtaining a desired target pattern having a plurality of features to be imaged on a substrate; (b) simulating a wafer image utilizing the target pattern and process parameters associated with a defined process; (c) defining at least one feature category; (d) identifying features in the target pattern that correspond to the at least one feature category, and recording an error value for each feature identified as corresponding to the at least one feature category; and (e) generating a statistical summary which indicates the error value for each feature identified as corresponding to the at least one feature category.

Method for performing full-chip manufacturing reliability checking and correction

Model OPC is developed based on eigen decomposition of an aerial image expected to be produced by a mask pattern on a surface of a resist. With the eigen decomposition method the aerial image intensity distribution around a point (x, y) is accurately described in the model. A scalar approach may be used in the eigen decomposition model which treats the light wave through the mask as a scalar quantity. A eigen decomposition alternatively may use a vector approach which utilizes a vector to describe the light wave and the pupil function. A predicted SPIF may be generated from the aerial image which may be used to verify the mask modeling process by comparing the predicted SPIF to an experimentally determined SPIF. The model OPC, once calibrated, may be used to evaluate performance of a mask and refine features of the mask.

Eigen decomposition based OPC model

Disclosed concepts include a method, program product and apparatus for generating assist features for a pattern to be formed on the surface of a substrate by generating an image field map corresponding to the pattern. Characteristics are extracted from the image field map, and assist features are generated for the pattern in accordance with the characteristics extracted in step. The assist features may be oriented relative to a dominant axis of a contour of the image field map. Also, the assist features may be polygon-shaped and sized to surround the contour or relative to the inside of the contour. Moreover, the assist features may be placed in accordance with extrema identified from the image field map. Utilizing the image field map, a conventional and complex two-dimensional rules-based approach for generating assist feature can be obviated.

Method, program product and apparatus for generating assist features utilizing an image field map

A method for modeling a photolithography process which includes the steps of generating a calibrated model of the photolithography process capable of estimating an image to be produced by the photolithography process when utilized to image a mask pattern containing a plurality features; and determining an operational window of the calibrated model, which defines whether or not the calibrated model can accurately estimate the image to be produced by a given feature in the mask pattern.

Method of manufacturing reliability checking and verification for lithography process using a calibrated eigen decomposition model

Method of predicting and minimizing model OPC deviation due to mix/match of exposure tools using a calibrated Eigen decomposition model

A method of automatically applying optical proximity correction techniques to a reticle design containing a plurality of features. The method comprises the steps of: (1) generating a first set of rules for applying scatter bar assist features to the plurality of features for a given illumination setting; (2) generating a second set of rules for applying biasing to the plurality of features for said given illumination setting; (3) forming a look-up table containing the first set of rules and the second set of rules; and (4) analyzing each of the plurality of features with the first set of rules and the second set of rules contained in the look-up table to determine if either the first set of rules or the second set of rules is applicable to a given feature. If either the first set of rules or the second set of rules is applicable to the given feature, the given feature is modified in accordance with the applicable rule.

Growing community of inventors

San Jose, CA, United States of America

Xuelong Shi