Patents by Inventor Pradeep Subrahmanyan

Pradeep Subrahmanyan 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: 20180253017
    Abstract: A process control system may include a controller configured to receive after-development inspection (ADI) data after a lithography step for the current layer from an ADI tool, receive after etch inspection (AEI) overlay data after an exposure step of the current layer from an AEI tool, train a non-zero offset predictor with ADI data and AEI overlay data to predict a non-zero offset from input ADI data, generate values of the control parameters of the lithography tool using ADI data and non-zero offsets generated by the non-zero offset predictor, and provide the values of the control parameters to the lithography tool for fabricating the current layer on the at least one production sample.
    Type: Application
    Filed: January 10, 2018
    Publication date: September 6, 2018
    Inventors: Michael E. Adel, Amnon Manassen, William Pierson, Ady Levy, Pradeep Subrahmanyan, Liran Yerushalmi, DongSub Choi, Hoyoung Heo, Dror Alumot, John Charles Robinson
  • Publication number: 20180196358
    Abstract: A lithography system includes an illumination source, one or more projection optical elements, and a pattern mask. The illumination source includes one or more illumination poles. The pattern mask includes a set of focus-sensitive mask elements periodically distributed with a pitch, wherein the set of focus-sensitive mask elements is configured to diffract illumination from the one or more illumination poles. The pitch is selected such that two diffraction orders of illumination associated with each of the one or more illumination poles are asymmetrically distributed in a pupil plane of the one or more projection optical elements. Further, the one or more projection optical elements are configured to expose a sample with an image of the set of focus-sensitive pattern mask elements based on the two diffraction orders of illumination associated with each of the one or more illumination poles.
    Type: Application
    Filed: January 24, 2017
    Publication date: July 12, 2018
    Inventors: Myungjun Lee, Stewart Robertson, Mark D. Smith, Pradeep Subrahmanyan
  • Publication number: 20170045826
    Abstract: A lithography system includes an illumination source and a set of projection optics. The illumination source directs a beam of illumination from an off-axis illumination pole to a pattern mask. The pattern mask includes a set of pattern elements to generate a set of diffracted beams including illumination from the illumination pole. At least two diffracted beams of the set of diffracted beams received by the set of projection optics are asymmetrically distributed in a pupil plane of the set of projection optics. The at least two diffracted beams of the set of diffracted beams are asymmetrically incident on the sample to form a set of fabricated elements corresponding to an image of the set of pattern elements. The set of fabricated elements on the sample includes one or more indicators of a location of the sample along an optical axis of the set of projection optics.
    Type: Application
    Filed: June 6, 2016
    Publication date: February 16, 2017
    Inventors: Myungjun Lee, Mark D. Smith, Sanjay Kapasi, Stilian Pandev, Dimitry Sanko, Pradeep Subrahmanyan, Ady Levy
  • Publication number: 20160268156
    Abstract: An apparatus tor fixing a wafer, including a chuck having a surface, a plurality of through bores in the chuck extending through the surface of the chuck, a fixed vacuum bellows, and a plurality of floating air bearings, wherein the fixed vacuum bellows and a respective floating air bearing of the plurality of floating air bearings are each individually arranged in separate through bores of the plurality of through bores and elevationally above the surface of the chuck.
    Type: Application
    Filed: March 9, 2016
    Publication date: September 15, 2016
    Inventors: Pradeep Subrahmanyan, Luping HUANG, Chris POHLHAMMER
  • Publication number: 20150310160
    Abstract: A method and system for generating high density registration maps for masks is disclosed. A data preparation module generates a plurality of anchor points of the mask. Additionally, the data preparation module generates a plurality of sample points. Weights are generated as well in the data preparation module and the weights are used later on in the data fusion module. The positions of anchor points are measured with a registration tool in a mask coordinate system according to a generated recipe. The positions of sample points are determined with an inspection tool in a mask coordinate system according to a generated recipe. The measured positions of the anchor points and the measured positions of the sample points are passed to a data fusion module where a registration map is determined.
    Type: Application
    Filed: July 9, 2015
    Publication date: October 29, 2015
    Inventors: Frank LASKE, Mohammad M. DANESHPANAH, Pradeep SUBRAHMANYAN, Yalin XIONG
  • Patent number: 8779635
    Abstract: A reticle positioning apparatus for actinic EUV reticle inspection including a sealed inspection chamber containing a reticle stage for holding a reticle. The reticle stage has a magnetically suspended upper stage with a long travel in a “y” direction and a magnetically suspended lower stage with a long travel in an “x” direction; and a cable stage chamber isolated from the inspection chamber by a cable chamber wall. The cable stage chamber has a cable stage movable in the “y” direction; and a tube connected at one end to the reticle stage and to the cable stage at the other end. The tube passes from the cable stage through the inspection chamber through a seal in the chamber wall and opening into the cable entry chamber for entry of cables and hoses within the cable stage chamber, which cables and hoses pass through the tube to the reticle stage.
    Type: Grant
    Filed: April 9, 2013
    Date of Patent: July 15, 2014
    Assignee: KLA-Tencor Corporation
    Inventors: Pradeep Subrahmanyan, Mark Williams, Samir Nayfeh
  • Patent number: 8772731
    Abstract: A method for synchronizing sample stage motion with a time delay integration (TDI) charge-couple device (CCD) in a semiconductor inspection tool, including: measuring a lateral position of a stage holding a sample being inspected; measuring a vertical position of the stage; determining a corrected lateral position of an imaged pixel of the sample based on the measured lateral and vertical positions; and synchronizing charge transfer of the TDI CCD with the corrected lateral position of the imaged pixel.
    Type: Grant
    Filed: April 12, 2013
    Date of Patent: July 8, 2014
    Assignee: KLA-Tencor Corporation
    Inventors: Pradeep Subrahmanyan, Daniel Wack, Michael Wright, David Alles
  • Publication number: 20130270444
    Abstract: A method for synchronizing sample stage motion with a time delay integration (TDI) charge-couple device (CCD) in a semiconductor inspection tool, including: measuring a lateral position of a stage holding a sample being inspected; measuring a vertical position of the stage; determining a corrected lateral position of an imaged pixel of the sample based on the measured lateral and vertical positions; and synchronizing charge transfer of the TDI CCD with the corrected lateral position of the imaged pixel.
    Type: Application
    Filed: April 12, 2013
    Publication date: October 17, 2013
    Applicant: KLA-Tencor Corporation
    Inventors: Pradeep Subrahmanyan, Daniel Wack, Michael Wright, David Alles
  • Publication number: 20130264494
    Abstract: A reticle positioning apparatus for actinic EUV reticle inspection including a sealed inspection chamber containing a reticle stage for holding a reticle. The reticle stage has a. magnetically suspended upper stage with a long travel in a “y” direction and a magnetically suspended lower stage with a long travel in an “x” direction; and a cable stage chamber isolated from the inspection chamber by a cable chamber wall. The cable stage chamber has a cable stage movable in the “y” direction; and a tube connected at one end to the reticle stage and to the cable stage at the other end, The tube passes from the cable stage through the inspection chamber through a seal in the chamber wail and opening into the cable entry chamber for entry of cables and hoses within the cable stage chamber, which cables and hoses pass through the tube to the reticle stage.
    Type: Application
    Filed: April 9, 2013
    Publication date: October 10, 2013
    Inventors: Pradeep Subrahmanyan, Mark Williams, Samir Nayfeh
  • Publication number: 20050087522
    Abstract: A method and laser system effect rapid removal of material from a workpiece by applying heating energy in the form of a light beam to a target location on the workpiece to elevate its temperature while maintaining its dimensional stability. When the target portion of the workpiece is heated, a laser beam is directed for incidence on the heated target location. The laser beam preferably has a processing laser output that is appropriate to effect removal of the target material from the workpiece. The combined incidence of the processing laser output and the heating energy on the target location enables the processing laser output to remove a portion of the target material at a material removal rate that is higher than the material removal rate achievable when the target material is not heated.
    Type: Application
    Filed: February 11, 2004
    Publication date: April 28, 2005
    Inventors: Yunlong Sun, Liu Jinjiao, Richard Harris, Pradeep Subrahmanyan, Robert Hainsey, Weixiong Lu