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Removing Deleterious Inorganic Residues Resulting from Permanganate Chromic Etching

IP.com Disclosure Number: IPCOM000085569D
Original Publication Date: 1976-Apr-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Anschel, M: AUTHOR

Abstract

Metallurgical corrosion problems primarily localized in the termination pad regions of gas panel displays and glass plates containing etched Cr/Cu/Cr metallurgy occur within 500 hours exposure to temperature and humidity (85 degrees C/81%RH).

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Removing Deleterious Inorganic Residues Resulting from Permanganate Chromic Etching

Metallurgical corrosion problems primarily localized in the termination pad regions of gas panel displays and glass plates containing etched Cr/Cu/Cr metallurgy occur within 500 hours exposure to temperature and humidity (85 degrees C/81%RH).

The primary cause for corrosion is attributed to the corrosive effects of residual manganese dioxide and chloride contamination. Sources for chloride and manganese dioxide are: 1) Glass dielectric etch-back process. 2) Trichloroethylene dissolution of black wax. 3) Alkaline permanganate etching of the top chrome layer prior to panel termination and permanganate etching of bottom chrome following photoresist application. 4) Reaction of potassium permanganate and reducing agents such as light, fingerprints and organic residues which yield manganese dioxide.

The following procedure has been found to give stain (MnO(2)) free surfaces. Basically, the procedure involves the conversion of manganese dioxide stains to an alcohol/and or water soluble manganese compound, namely, manganese lactate as illustrated in the drawing.

The procedure for the conversion of deleterious MnO(2) to innocuous manganese lactate following the chrome etch step is set forth as follows: 1) Load plates into rack. 2) Place loaded rack into a 50:50 solution composed of lactic acid:methanol. 3) Agitate each rack by hand in the solution for ten (10) minutes.
4) DI water rinse at...