Patents by Inventor Ron-Hon Chen

Ron-Hon Chen 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).

  • Image developing method utilizing sodium sulfide and ammonium polysulfide developer solution whereby exposed copper substrate surface changes color
    Patent number: 5215865
    Abstract: An image development method is disclosed. In the method, a photoresist layer on a metal surface is exposed for development. The developer then used is a solution which will both develop the photoresist image and cause any exposed metal surface to change to a predetermined color. The development process then proceeds until the predetermined color is exposed whereupon the process ceases. The preferred metal is copper and the preferred developer is an aqueous solution of sodium sulphide and ammonium polysulfide.
    Type: Grant
    Filed: August 3, 1991
    Date of Patent: June 1, 1993
    Inventor: Ron-Hon Chen