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Selective Chromium Stripping

IP.com Disclosure Number: IPCOM000089529D
Original Publication Date: 1977-Nov-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Murphy, JA: AUTHOR [+3]

Abstract

One gas panel metallurgy system utilizes multilayer conductor arrays of chrome-copper-chrome in which the copper functions as the conductor, the lower layer of chrome provides adhesion to the glass, and the upper chrome protects the copper during subsequent processing from attack by the dielectric glass frit during dielectric reflow. These conductors are terminated on terminal line pads on opposite sides of the plate.

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Selective Chromium Stripping

One gas panel metallurgy system utilizes multilayer conductor arrays of chrome-copper-chrome in which the copper functions as the conductor, the lower layer of chrome provides adhesion to the glass, and the upper chrome protects the copper during subsequent processing from attack by the dielectric glass frit during dielectric reflow. These conductors are terminated on terminal line pads on opposite sides of the plate.

To check for open conductors in the array, one end of the plate is immersed in a chromium stripping solution of KMnO(4), Na(3)PO(4), and NaOH, and a negative current is applied from the opposite end of the plate. Any terminal pad not connected to a negative potential is stripped of chrome, but conductors which are connected are cathodically protected and the chrome remains. For a selective stripping operation, any continuous lines which are to be stripped must be isolated from the applied current, which is kept near 100 milliamperes per square inch in order to protect the chrome from the etch.

By stripping the chrome from the pads of the open conductors, repairs can be made or the panel driven from opposite sides by interconnecting conductors to opposite ends of the open line. Visual identification of line opens is provided because of a bluish tarnish of the chromium resulting from reflow. The subject device thus provides selective stripping of chromium pads on open lines and visual identification of pads in need of repa...