Patents by Inventor Hwan Soo Chang

Hwan Soo Chang 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).

  • Stepper light control using movable blades
    Patent number: 5675402
    Abstract: The present invention discloses a light control means in a stepper.The light control means of the present invention has a twofold structure consisted of at least more than two blades which open a circuit pattern designed on a reticle; and a subblade which can close selectively a portion of the circuit pattern. The sub-blade is mounted above or below one of the at least more than two blades, and is movable in every directions in response to the instruction from the blade control system.Accordingly, the present invention provides a exposure process which can selectively cover only the dies that will be overlapped with the EBR gap of the wafer using sub-blade, thereby increasing the number of the net-die.
    Type: Grant
    Filed: October 20, 1995
    Date of Patent: October 7, 1997
    Assignee: Hyundai Electronics Industries Co., Ltd.
    Inventors: Chan Seob Cho, Hwan Soo Chang, Myung Gun Gil