Activated Carbon to Remove Thiourea From Acidic Rinse Water
Original Publication Date: 1985-Jun-01
Included in the Prior Art Database: 2005-Feb-18
One of the steps involved in the fabrication of plasma display panels is the formation of conductor arrays on glass substrates. The plates are fabricated by applying to the glass substrates a chromium layer followed by a copper layer followed by a chromium layer. Next a positive photoresist composition is applied so that selected areas of the chrome/copper/chrome layers can be removed to provide the desired conductor pattern on the substrates. Because of the interaction between alkaline etchants and the positive photoresist, the quality of the conductor array is severely affected when a basic etchant is used for chromium removal. Therefore, an aqueous acid/thiourea etchant was developed and employed in the chromium removal process.