Patents by Inventor Christopher J. Ashton

Christopher J. Ashton 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: 5051598
    Abstract: A proximity effect correction method for electron beam lithography suitable for high voltages and/or very dense patterns applies both backscatter and forward scatter dose corrections. Backscatter dose corrections are determined by computing two matrices, a "Proximity Matrix" P and a "Fractional Density Matrix" F. The Proximity Matrix P is computed using known algorithms. The elements of the Fractional Density Matrix are the fractional shape coverage in a mesh of square cells which is superimposed on a pattern of interest. Then, a Dose Correction Matrix D is computed by convolving the P and F matrices. The final backscatter dose corrections are assigned to each shape either as area-weighted averages of the D matrix elements for all cells spanned by the shape, or by polynomial or other interpolation of the dose correction field defined by the D matrix. The D matrix also provides a basis for automatic shape fracturing for optimal proximity correction.
    Type: Grant
    Filed: September 12, 1990
    Date of Patent: September 24, 1991
    Assignee: International Business Machines Corporation
    Inventors: Christopher J. Ashton, Porter D. Gerber, Dieter P. Kern, Walter W. Molzen, Jr., Stephen A. Rishton, Michael G. Rosenfield, Raman G. Viswanathan
  • Patent number: 4295754
    Abstract: There is disclosed a temporary structure for use in exhibition stands and the like, comprising a framework comprising rectangular frame units each comprising two parallel vertical tubes and two horizontal spars, each in the form of an H with a much elongated cross member and much shortened uprights each of which provides two plugs, respectively above and below the cross member, two said plugs of each said horizontal spar being engaged in respective sockets afforded by the ends of respective ones of the two vertical tubes of the respective frame unit.In an extended structure each horizontal spar may form the lower spar of one such rectangular frame unit and the upper spar of an adjoining lower frame unit. Spring collets may be fitted around the plugs and within the sockets in which the plugs are inserted the colletts having cutting edges to score the socket walls, and having internal projections fitting in recesses in the plugs whereby a firm non-rotatable connection can be obtained.
    Type: Grant
    Filed: March 29, 1979
    Date of Patent: October 20, 1981
    Assignee: Marler Haley Exposystems Limited
    Inventors: Christopher J. Ashton, Andrew C. Diamond, Derek H. Greenhill
  • Patent number: D281513
    Type: Grant
    Filed: March 17, 1982
    Date of Patent: November 26, 1985
    Assignee: Marler Haley ExpoSystems, Limited
    Inventor: Christopher J. Ashton