Patents by Inventor Micheal Cranford

Micheal Cranford 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).

  • Patent number: 8490032
    Abstract: Techniques and systems for converting a non-bandlimited pattern layout into a band-limited pattern image are described. During operation, the system receives the non-bandlimited pattern layout which comprises one or more polygons. The system further receives an anti-aliasing filter (AAF) kernel, wherein the AAF kernel is configured to convert a non-bandlimited pattern into a band-limited pattern. The system then constructs an AAF lookup table for the AAF kernel, wherein the AAF lookup table contains precomputed values for a set of convolution functions which are obtained by convolving a set of basis functions with the AAF kernel. Next, the system creates a sampled pattern layout by applying a grid map over the pattern layout. The system then obtains the band-limited pattern image by using the AAF lookup table to convolve the AAF kernel with each grid location in the sampled pattern layout.
    Type: Grant
    Filed: September 28, 2010
    Date of Patent: July 16, 2013
    Assignee: Synopsys, Inc.
    Inventors: Michael L. Rieger, Micheal Cranford, John P. Stirniman
  • Publication number: 20110016438
    Abstract: Techniques and systems for converting a non-bandlimited pattern layout into a band-limited pattern image are described. During operation, the system receives the non-bandlimited pattern layout which comprises one or more polygons. The system further receives an anti-aliasing filter (AAF) kernel, wherein the AAF kernel is configured to convert a non-bandlimited pattern into a band-limited pattern. The system then constructs an AAF lookup table for the AAF kernel, wherein the AAF lookup table contains precomputed values for a set of convolution functions which are obtained by convolving a set of basis functions with the AAF kernel. Next, the system creates a sampled pattern layout by applying a grid map over the pattern layout. The system then obtains the band-limited pattern image by using the AAF lookup table to convolve the AAF kernel with each grid location in the sampled pattern layout.
    Type: Application
    Filed: September 28, 2010
    Publication date: January 20, 2011
    Applicant: SYNOPSYS, INC.
    Inventors: Michael L. Rieger, Micheal Cranford, John P. Stirniman
  • Patent number: 7831954
    Abstract: An embodiment of the present invention provides a system that computes the effect of perturbations to a pattern layout during an OPC process. During operation, the system receives a pattern layout and a set of lithography model kernels. The system then obtains a set of convolved patterns by convolving the pattern layout with each of the set of lithography model kernels. The system additionally receives a perturbation pattern to be added onto the pattern layout. Next, for a query location on the pattern layout, the system obtains a set of convolution values at the query location by using model flash lookup tables to convolve the perturbation pattern with the set of lithography model kernels. The system then updates the set of convolved patterns at the query location to account for the effect of the perturbation pattern by combining the set of convolution values with the set of convolved patterns.
    Type: Grant
    Filed: September 25, 2007
    Date of Patent: November 9, 2010
    Assignee: Synopsys, Inc.
    Inventors: Michael L. Rieger, Micheal Cranford, John P. Stirniman
  • Patent number: 7617478
    Abstract: One embodiment of the present invention provides a system that converts a non-bandlimited pattern layout into a band-limited pattern image to facilitate simulating an optical lithography process. During operation, the system receives the non-bandlimited pattern layout which comprises one or more polygons. The system further receives an anti-aliasing filter (AAF) kernel, wherein the AAF kernel is configured to convert a non-bandlimited pattern into a band-limited pattern. The system then constructs an AAF lookup table for the AAF kernel, wherein the AAF lookup table contains precomputed values for a set of convolution functions which are obtained by convolving a set of basis functions with the AAF kernel. Next, the system creates a sampled pattern layout by applying a grid map over the pattern layout. The system then obtains the band-limited pattern image by using the AAF lookup table to convolve the AAF kernel with each grid location in the sampled pattern layout.
    Type: Grant
    Filed: September 25, 2007
    Date of Patent: November 10, 2009
    Assignee: Synopsys, Inc.
    Inventors: Michael L. Rieger, Micheal Cranford, John P. Stirniman
  • Publication number: 20090083693
    Abstract: Another embodiment of the present invention provides a system that computes the effect of perturbations to an input pattern layout during an OPC (Optical Proximity Correction) process. During operation, the system receives a pattern layout. The system further receives a set of lithography model kernels. The system then obtains a set of convolved patterns by convolving the pattern layout with each of the set of lithography model kernels. Next, the system computes a model flash lookup table for each of the lithography model kernels, wherein the model flash lookup table contains precomputed values for a set of convolution functions obtained by convolving a set of basis functions with the lithography model kernel. The system additionally receives a perturbation pattern to be added onto the pattern layout.
    Type: Application
    Filed: September 25, 2007
    Publication date: March 26, 2009
    Applicant: SYNOPSYS, INC.
    Inventors: Michael L. Rieger, Micheal Cranford, John P. Stirniman
  • Publication number: 20090083692
    Abstract: One embodiment of the present invention provides a system that converts a non-bandlimited pattern layout into a band-limited pattern image to facilitate simulating an optical lithography process. During operation, the system receives the non-bandlimited pattern layout which comprises one or more polygons. The system further receives an anti-aliasing filter (AAF) kernel, wherein the AAF kernel is configured to convert a non-bandlimited pattern into a band-limited pattern. The system then constructs an AAF lookup table for the AAF kernel, wherein the AAF lookup table contains precomputed values for a set of convolution functions which are obtained by convolving a set of basis functions with the AAF kernel. Next, the system creates a sampled pattern layout by applying a grid map over the pattern layout. The system then obtains the band-limited pattern image by using the AAF lookup table to convolve the AAF kernel with each grid location in the sampled pattern layout.
    Type: Application
    Filed: September 25, 2007
    Publication date: March 26, 2009
    Applicant: SYNOPSYS, INC.
    Inventors: Michael L. Rieger, Micheal Cranford, John P. Stirniman
  • Publication number: 20070101310
    Abstract: A memory is encoded with a model of sensitivity of a distorted layout generated by simulation of a wafer fabrication process, with respect to a change in an original layout that is input to the simulation. The sensitivity model comprises an expression of convolution of the original layout with spatial functions (“kernels”) that are identical to kernels of a process model used in the simulation. A difference between the distorted layout and the original layout is computed, and the difference is divided by a sensitivity value which is obtained directly by evaluating the kemel-based sensitivity model, and the result is used to identify a proximity correction (such as serif size or contour movement) to be made to the original layout. Use of a sensitivity model based on a process model's kernels eliminates a second application of the process model to evaluate sensitivity, thereby to reduce memory and computation requirements.
    Type: Application
    Filed: October 31, 2005
    Publication date: May 3, 2007
    Inventors: John Stirniman, Micheal Cranford