Disclosed is a sculpted probe pad and a gray scale etching process for making arrays of such probe pads on a thin flexible interposer for testing the electrical integrity of microelectronic devices at terminal metallurgy. Also used in the etching process is a novel fixture for holding the substrate and...http://www.google.de/patents/US6156484?utm_source=gb-gplus-sharePatent US6156484 - Gray scale etching for thin flexible interposer
