Patents by Inventor Yongfa Fan

Yongfa Fan has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20210294218
    Abstract: A process to model post-exposure effects in patterning processes, the process including: obtaining values based on measurements of structures formed on one or more substrates by a post-exposure process and values of a pair of process parameters by which process conditions were varied; modeling, by a processor system, as a surface, correlation between the values based on measurements of the structures and the values of the pair of process parameters; and storing the model in memory.
    Type: Application
    Filed: July 27, 2017
    Publication date: September 23, 2021
    Applicant: ASML NETHERLANDS B.V.
    Inventors: Yongfa FAN, Mu FENG, Leiwu ZHENG, Qian ZHAO, Jen-Shiang WANG
  • Publication number: 20190354020
    Abstract: A method involving determining an etch bias for a pattern to be etched using an etch step of a patterning process based on an etch bias model, the etch bias model including a formula having a variable associated with a spatial property of the pattern or with an etch plasma species concentration of the etch step, and including a mathematical term including a natural exponential function to the power of a parameter that is fitted or based on an etch time of the etch step; and adjusting the patterning process based on the determined etch bias.
    Type: Application
    Filed: February 21, 2018
    Publication date: November 21, 2019
    Applicant: ASML NETHERLANDS B.V.
    Inventors: Yongfa FAN, Leiwu ZHENG, Mu FENG, Qian ZHAO, Jen-Shiang WANG
  • Patent number: 8918743
    Abstract: A method and apparatus of a novel full chip edge-based mask three-dimensional (3D) model for performing photolithography simulation is described. The method applies a thin mask model to a mask design layout to create a thin mask transmission. The method generates a thick mask model that has a plurality of edge-based kernels. The method applies the thick mask model to the mask design layout to create a mask 3D residual. The method combines the thin mask transmission and the mask 3D residual to create a mask 3D transmission.
    Type: Grant
    Filed: August 12, 2013
    Date of Patent: December 23, 2014
    Assignee: Synopsys, Inc.
    Inventors: Qiliang Yan, Hongbo Zhang, Ebo Croffie, Lin Zhang, Yongfa Fan, Peter Brooker, Qian Ren
  • Patent number: 8875066
    Abstract: Computer-implemented techniques for pixel source optics calculations using spatial coherence are disclosed. Pixelated sources are used for source-mask co-optimization to enhance semiconductor lithography. Calculation of a partially coherent imaging system is used for optical-lithography simulation. The spatial coherence property of neighboring source points is used to reduce imaging calculation complexity. Two or more neighboring points are treated as one pseudo-spatially coherent area element.
    Type: Grant
    Filed: March 15, 2013
    Date of Patent: October 28, 2014
    Assignee: Synopsys, Inc.
    Inventors: Yongfa Fan, Thomas Schmoeller
  • Publication number: 20140282298
    Abstract: Computer-implemented techniques for pixel source optics calculations using spatial coherence are disclosed. Pixelated sources are used for source-mask co-optimization to enhance semiconductor lithography. Calculation of a partially coherent imaging system is used for optical-lithography simulation. The spatial coherence property of neighboring source points is used to reduce imaging calculation complexity. Two or more neighboring points are treated as one pseudo-spatially coherent area element.
    Type: Application
    Filed: March 15, 2013
    Publication date: September 18, 2014
    Applicant: Synopsys, Inc.
    Inventors: Yongfa Fan, Thomas Schmoeller
  • Patent number: 8812145
    Abstract: One embodiment of the present invention provides techniques and systems for modeling mask errors based on aerial image sensitivity. During operation, the system can receive an uncalibrated process model which includes a mask error modeling term which is based at least on an aerial image sensitivity to mask modifications which represent mask errors. Next, the system can fit the uncalibrated process model using measured CD data. Note that the mask error modeling term can also be dependent on the local and/or long-range pattern density. In some embodiments, the mask error modeling term can include an edge bias term and a corner rounding term. The edge bias term can be based on the sensitivity of the aerial image intensity to an edge bias, and the corner rounding term can be based on the sensitivity of the aerial image intensity to a corner rounding adjustment.
    Type: Grant
    Filed: January 14, 2013
    Date of Patent: August 19, 2014
    Assignee: Synopsys, Inc.
    Inventors: Yongfa Fan, JenSheng Huang
  • Patent number: 8355807
    Abstract: One embodiment of the present invention provides techniques and systems for modeling mask errors based on aerial image sensitivity. During operation, the system can receive an uncalibrated process model which includes a mask error modeling term which is based at least on an aerial image sensitivity to mask modifications which represent mask errors. Next, the system can fit the uncalibrated process model using measured CD data. Note that the mask error modeling term can also be dependent on the local pattern density. In some embodiments, the mask error modeling term can include an edge bias term and a corner rounding term. The edge bias term can be based on the sensitivity of the aerial image intensity to an edge bias, and the corner rounding term can be based on the sensitivity of the aerial image intensity to a corner rounding adjustment.
    Type: Grant
    Filed: January 22, 2010
    Date of Patent: January 15, 2013
    Assignee: Synopsys, Inc.
    Inventors: Yongfa Fan, JenSheng Huang
  • Patent number: 8296688
    Abstract: One embodiment of the present invention provides a system that determines an assist feature placement within a post-optical proximity correction (post-OPC) mask layout. During operation, the system receives a set of target patterns which represent a set of polygons in a pre-OPC mask layout. The system then constructs a focus-sensitive cost function based on the target patterns, wherein the focus-sensitive cost function represents an amount of movement of post-OPC contours of the target patterns in response to changes in focus condition of the lithography system. Next, the system computes a cost-covariance field (CCF field) based on the focus-sensitive cost function, wherein the CCF field is a two-dimensional (2D) map representing changes to the focus-sensitive cost function due to an addition of a pattern at a given location within the post-OPC mask layout. Finally, the system generates assist features for the post-OPC mask layout based on the CCF field.
    Type: Grant
    Filed: April 26, 2011
    Date of Patent: October 23, 2012
    Assignee: Synopsys, Inc.
    Inventors: Levi D. Barnes, Benjamin D. Painter, Qiliang Yan, Yongfa Fan, Jianliang Li, Amyn Poonawala
  • Patent number: 8161424
    Abstract: Some embodiments provide a system for accurately and efficiently modeling chemically amplified resist. During operation, the system can determine a quenched acid profile from an initial acid profile by applying multiple quenching models which are associated with different acid concentration ranges to the initial acid profile. One quenching model may be expressed as H=H0?B0, where H is an acid profile after quenching, H0 is an acid profile before quenching, and B0 is an initial base quencher profile. Another quenching model may be expressed as H=k·H0, where k is a constant. Next, the system can apply a smoothing kernel to the quenched acid profile to obtain a quenched-and-diffused acid profile. The smoothing kernel can generally be any weighted averaging function. The quenched-and-diffused acid profile can then be used to predict shapes that are expected to print on the wafer and to perform resolution enhancement techniques on a layout.
    Type: Grant
    Filed: July 28, 2009
    Date of Patent: April 17, 2012
    Assignee: Synopsys, Inc.
    Inventor: Yongfa Fan
  • Patent number: 8006203
    Abstract: 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.
    Type: Grant
    Filed: August 28, 2008
    Date of Patent: August 23, 2011
    Assignee: Synopsys, Inc.
    Inventors: Yongfa Fan, Qiaolin Zhang, Bradley J. Falch
  • Publication number: 20110202891
    Abstract: One embodiment of the present invention provides a system that determines an assist feature placement within a post-optical proximity correction (post-OPC) mask layout. During operation, the system receives a set of target patterns which represent a set of polygons in a pre-OPC mask layout. The system then constructs a focus-sensitive cost function based on the target patterns, wherein the focus-sensitive cost function represents an amount of movement of post-OPC contours of the target patterns in response to changes in focus condition of the lithography system. Note that the contours of the target patterns substantially coincide with the edges of set of the polygons. Next, the system computes a cost-covariance field (CCF field) based on the focus-sensitive cost function, wherein the CCF field is a two-dimensional (2D) map representing changes to the focus-sensitive cost function due to an addition of a pattern at a given location within the post-OPC mask layout.
    Type: Application
    Filed: April 26, 2011
    Publication date: August 18, 2011
    Applicant: SYNOPSYS, INC.
    Inventors: Levi D. Barnes, Benjamin D. Painter, Qiliang Yan, Yongfa Fan, Jianliang Li, Amyn Poonawala
  • Publication number: 20110184546
    Abstract: One embodiment of the present invention provides techniques and systems for modeling mask errors based on aerial image sensitivity. During operation, the system can receive an uncalibrated process model which includes a mask error modeling term which is based at least on an aerial image sensitivity to mask modifications which represent mask errors. Next, the system can fit the uncalibrated process model using measured CD data. Note that the mask error modeling term can also be dependent on the local pattern density. In some embodiments, the mask error modeling term can include an edge bias term and a corner rounding term. The edge bias term can be based on the sensitivity of the aerial image intensity to an edge bias, and the corner rounding term can be based on the sensitivity of the aerial image intensity to a corner rounding adjustment.
    Type: Application
    Filed: January 22, 2010
    Publication date: July 28, 2011
    Applicant: SYNOPSYS, INC.
    Inventors: Yongfa Fan, JenSheng Huang
  • Patent number: 7954071
    Abstract: One embodiment of the present invention provides a system that determines an assist feature placement within a post-optical proximity correction (post-OPC) mask layout. During operation, the system receives a set of target patterns which represent a set of polygons in a pre-OPC mask layout. The system then constructs a focus-sensitive cost function based on the target patterns, wherein the focus-sensitive cost function represents an amount of movement of post-OPC contours of the target patterns in response to changes in focus condition of the lithography system. Note that the contours of the target patterns substantially coincide with the edges of set of the polygons. Next, the system computes a cost-covariance field (CCF field) based on the focus-sensitive cost function, wherein the CCF field is a two-dimensional (2D) map representing changes to the focus-sensitive cost function due to an addition of a pattern at a given location within the post-OPC mask layout.
    Type: Grant
    Filed: October 31, 2008
    Date of Patent: May 31, 2011
    Assignee: Synopsys, Inc.
    Inventors: Levi D. Barnes, Benjamin D. Painter, Qiliang Yan, Yongfa Fan, Jianliang Li, Amyn Poonawala
  • Publication number: 20110029118
    Abstract: Some embodiments provide a system for accurately and efficiently modeling chemically amplified resist. During operation, the system can determine a quenched acid profile from an initial acid profile by applying multiple quenching models which are associated with different acid concentration ranges to the initial acid profile. One quenching model may be expressed as H=H0?B0, where H is an acid profile after quenching, H0 is an acid profile before quenching, and B0 is an initial base quencher profile. Another quenching model may be expressed as H=k·H0, where k is a constant. Next, the system can apply a smoothing kernel to the quenched acid profile to obtain a quenched-and-diffused acid profile. The smoothing kernel can generally be any weighted averaging function. The quenched-and-diffused acid profile can then be used to predict shapes that are expected to print on the wafer and to perform resolution enhancement techniques on a layout.
    Type: Application
    Filed: July 28, 2009
    Publication date: February 3, 2011
    Applicant: SYNOPSYS, INC.
    Inventor: Yongfa Fan
  • Publication number: 20100115486
    Abstract: One embodiment of the present invention provides a system that determines an assist feature placement within a post-optical proximity correction (post-OPC) mask layout. During operation, the system receives a set of target patterns which represent a set of polygons in a pre-OPC mask layout. The system then constructs a focus-sensitive cost function based on the target patterns, wherein the focus-sensitive cost function represents an amount of movement of post-OPC contours of the target patterns in response to changes in focus condition of the lithography system. Note that the contours of the target patterns substantially coincide with the edges of set of the polygons. Next, the system computes a cost-covariance field (CCF field) based on the focus-sensitive cost function, wherein the CCF field is a two-dimensional (2D) map representing changes to the focus-sensitive cost function due to an addition of a pattern at a given location within the post-OPC mask layout.
    Type: Application
    Filed: October 31, 2008
    Publication date: May 6, 2010
    Applicant: SYNOPSYS, INC.
    Inventors: Levi D. Barnes, Benjamin D. Painter, Qiliang Yang, Yongfa Fan, Jianliang Li, Amyn Poonawala
  • Publication number: 20100058280
    Abstract: 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.
    Type: Application
    Filed: August 28, 2008
    Publication date: March 4, 2010
    Applicant: Synopsys, Inc.
    Inventors: Yongfa Fan, Qiaolin Zhang, Bradley John Falch