Patents Assigned to Possehl Sumiko Electronics Singapore PTE Ltd.
  • Patent number: 6130027
    Abstract: A process for producing lead frames having lead tips with a minimum of side etching includes the steps of coating a metal lead frame substrate with a first photosensitive film, patterning the first photosensitive film, developing the patterned first photosensitive film, partially etching the metal surface of the lead-frame substrate beneath the developed patterned first photosensitive film, coating the partially etched metal surface with a positive second photosensitive, exposing the positive second photosensitive film to light passing through the developed first photosensitive film, developing the exposed second photosensitive film, performing fine etching through the developed second photosensitive film to a desired depth at least once, and removing the first and second photosensitive films.
    Type: Grant
    Filed: February 4, 1998
    Date of Patent: October 10, 2000
    Assignees: Sumitomo Metal Mining Co., Ltd., Possehl Sumiko Electronics Singapore PTE Ltd.
    Inventor: Yoichiro Hamada