The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 05, 1998
Filed:
Nov. 08, 1995
Kunio Sano, Yamanashi-ken, JP;
Tokyo Electron Limited, Tokyo, JP;
Abstract
A probe card for examining the electrical characteristics of a plurality of IC chips formed on a semiconductor wafer has a card body and a printed wiring board. The card body has contact elements for contacting the electrodes pads of each IC chip. The printed wiring board has a plurality of transmission paths for transmitting a high-frequency signal to the contact elements. The printed wiring board has a plurality of signal lines disposed between first and second insulating layers, and first and second reference conductive plates opposing the signal lines through the first and second insulating layers, respectively. DC potentials that are different from each other are applied to the first and second reference conductive plates. The first and second reference conductive plates are arranged to be substantially offset from each other along each transmission path. The first and second reference conductive plates are arranged to slightly overlap each other. The overlapping amount is adjusted such that the impedances of the respective transmission paths are equal as a whole.