Source optimization for image fidelity and throughput

Patent metadata

Field	Value
Publication number	US-2016238950-A1
Application number	US-201615135339-A
Country	US
Kind code	A1
Filing date	Apr 21, 2016
Priority date	Feb 3, 2004
Publication date	Aug 18, 2016
Grant date	—

Abstract

A system and method for optimizing an illumination source to print a desired pattern of features dividing a light source into pixels and determining an optimum intensity for each pixel such that when the pixels are simultaneously illuminated, the error in a printed pattern of features is minimized. In one embodiment, pixel solutions are constrained from solutions that are bright, continuous, and smooth. In another embodiment, the light source optimization and resolution enhancement technique(s) are iteratively performed to minimize errors in a printed pattern of features.

First claim

1 - 22 . (canceled)

23 . A computer-readable medium storing a sequence of instructions that when executed by a computer causes the computer to perform a method, the instructions comprising:
instructions for receiving all or a portion of a layout database from which a target pattern of features to be created via a photolithographic process is selected; instructions for generating first corrected features of the layout database with a resolution enhancement technique to reduce imaging errors between the target pattern of features and an image produced on a wafer using the first corrected features; and instructions for selecting first pixel intensity values to be produced by an optical element when illuminated with light from an illumination light source, wherein the first pixel intensity values are selected to reduce imaging errors between the target pattern of features and the image produced on the wafer using the first pixel intensity values.

24 . The computer-readable medium of claim 23 , wherein the instructions further comprise:
instructions for generating second corrected features with a resolution enhancement technique applied to the first corrected features assuming illumination light produced by the optical element using the first pixel intensity values; and instructions for selecting second pixel intensity values to be produced by the optical element using the second corrected features, wherein the second pixel intensity values are selected to further reduce imaging errors between the target pattern of features and the image produced on the wafer using the second pixel intensity values.

25 . The computer-readable medium of claim 23 , wherein the instructions further comprise:
instructions for selecting second pixel intensity values to be produced by the optical element using the first corrected features, wherein the second pixel intensity values are selected to further reduce imaging errors between the target pattern of features and the image produced on the wafer using the second pixel intensity values; and instructions for generating second corrected features with a resolution enhancement technique applied to the first correct features assuming illumination light produced by the optical element using the second pixel intensity values.

26 . The computer-readable medium of claim 23 , wherein:
the illumination light source is a pixilated light source; and the instructions further comprise:
instructions for receiving a description of the pixilated light source, wherein the description comprises properties of the pixilated light source when the pixilated light source is used in a photolithographic process; and
instructions for generating a desired light source distribution for the pixilated light source, the generating comprising simulating the pixilated light source using means for evaluating image fidelity of an image approximating the target pattern of features produced on the wafer using the pixilated light source.

27 . The computer-readable medium of claim 23 , wherein:
the target pattern of features is a symmetrical pattern of layout features; the optical element is a diffractive optical element; and the instructions further comprise:
instructions for defining a mathematical relationship between one or more pixel intensities produced by the diffractive optical element and the target pattern of features; and
instructions for assigning pixel intensities for the diffractive optical element using the mathematical relationship in one or more computer simulations, wherein:
runtime for the computer simulations is reduced by simulating a portion, but not all, of the target pattern of features, and
the first pixel intensity values are calculated to produce an image of the target pattern of features on the wafer with greater image fidelity than other features in the layout database.

28 . A computer-readable medium storing a sequence of instructions that when executed by a computer causes the computer to perform a method, the instructions comprising:
instructions for receiving a description of a pixilated light source, the description defining properties of the pixilated light source when the pixilated light source is used in a photolithographic process; instructions for receiving a layout pattern defining a desired pattern of features to be produced on a wafer using the photolithographic process; instructions for generating a desired light source distribution for the pixilated light source, the generating comprising simulating the pixilated light source using means for evaluating image fidelity of an image approximating the desired pattern of features produced on a wafer using the pixilated light source; and instructions for generating a corrected layout pattern, the corrected layout pattern calculated to produce an image on a wafer that approximates the desired pattern of features.

29 . The computer-readable medium of claim 28 , wherein the simulating the pixilated light source uses the corrected layout pattern.

30 . The computer-readable medium of claim 28 , wherein the instructions further comprise instructions for iteratively repeating execution of the instructions for generating the desired light source distribution and generating the corrected layout pattern until a desired image fidelity is reached.

31 . The computer-readable medium of claim 28 , wherein the corrected layout pattern is generated using the desired light source distribution.

32 . The computer-readable medium of claim 31 , wherein the instructions further comprise instructions for iteratively repeating execution of the instructions for generating the desired light source distribution and generating the corrected layout pattern until a desired image fidelity is reached.

33 . The computer-readable medium of claim 28 , wherein the instructions further comprise instructions for iteratively repeating execution of the instructions for generating the desired light source distribution and generating the corrected layout pattern until a desired depth of focus is reached.

34 . The computer-readable medium of claim 28 , wherein the generating a desired light source distribution further comprises weighting one or more selected areas of the desired pattern of features such that the image on the wafer approximates the one or more selected areas with greater image fidelity than unselected areas of the desired pattern of features.

35 . The computer-readable medium of claim 28 , wherein the generating the desired light source distribution further comprises limiting source energy of one or more pixel intensities of the pixilated light source.

36 . The computer-readable medium of claim 28 , wherein the generating the desired light source distribution further comprises smoothing source intensities of one or more pixels of the pixilated light source.

37 . A computer-implemented method, comprising:
by a computer:
selecting a pattern of features in a layout database to be created on a wafer by determining a symmetrical pattern of layout features in the layout database;
defining a mathematical relationship between one or more pixel intensities produced by a diffractive optical element and the selected pattern of features; and
assigning pixel intensities for the diffractive optical element using the mathematical relationship in one or more computer simulations, wherein:
runtime for the computer simulations is reduced by simulating a portion, but not all, of the symmetrical pattern of layout features, and
the pixel intensities are calculated to produce an image of the selected pattern of features on the wa

Assignees

• Mentor Graphics Corp

Inventors

• Granik Yuri

Classifications

• G03F7/70491 Primary

  Information management, e.g. software; Active and passive control, e.g. details of controlling exposure processes or exposure tool monitoring processes · CPC title

• G03F7/70441

  Optical proximity correction [OPC] · CPC title

• G03F7/70108 Primary

  Off-axis setting using a light-guiding element, e.g. diffractive optical elements [DOEs] or light guides · CPC title

• G03F7/705

  Modelling or simulating from physical phenomena up to complete wafer processes or whole workflow in wafer productions · CPC title