Patents by Inventor Hajime Takaoka

Hajime Takaoka 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).

  • Mask pattern for alignment
    Patent number: 6118517
    Abstract: A reticle mask is provided which allows a determination of an offset amount of a circuit pattern on a mask with respect to reticle alignment marks based on the offset between the reticle alignment marks and position measurement patterns. The position measurement patterns are formed in the circuit pattern area surrounded by a light shielding area, and enables a determination of the offset amount of the circuit pattern with respect to the reticle alignment marks, thereby reducing an offset amount between overlaid circuit patterns.
    Type: Grant
    Filed: August 28, 1997
    Date of Patent: September 12, 2000
    Assignee: NEC Corporation
    Inventors: Takahiro Sasaki, Hajime Takaoka
  • Method of producing a semiconductor device
    Patent number: 5989762
    Abstract: An alignment correcting method for an aligner is disclosed. A designated number of wafers are selected out of a single lot and have their alignment marks measured in terms of coordinates. Subsequently, a preselected number of wafers are selected out of the wafers undergone measurement in the descending order with respect to closeness to a mean value or a center value of scattering, exposed, and then developed. An alignment correction value is calculated on the basis of the developed wafers.
    Type: Grant
    Filed: March 6, 1997
    Date of Patent: November 23, 1999
    Assignee: NEC Corporation
    Inventor: Hajime Takaoka