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Quality Control Methods for Evaporated MgO and Reflow Dielectric Surfaces

IP.com Disclosure Number: IPCOM000089262D
Original Publication Date: 1977-Oct-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

James, GA: AUTHOR [+2]

Abstract

In the deposition of multilayered dielectrics of MgO over sintered lead-rich glass on glass plate, such as might be used in plasma display panels, sometimes electrical instability may occur resulting in every line aging (ELA) voltage shift. Such a problem is largely due to the surface structural defects and compositional heterogeneity. A brief 1 to 20 minute citric acid solution etching on the surface will provide distinctive morphological information of the defect density, which can then be detected by using a scanning electron microscope at a moderate magnification. This method also can be applied to the quality control of sintered lead-rich dielectric glass layers, on plate glass, prior to deposition of an MgO coating over it.

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Quality Control Methods for Evaporated MgO and Reflow Dielectric Surfaces

In the deposition of multilayered dielectrics of MgO over sintered lead-rich glass on glass plate, such as might be used in plasma display panels, sometimes electrical instability may occur resulting in every line aging (ELA) voltage shift. Such a problem is largely due to the surface structural defects and compositional heterogeneity. A brief 1 to 20 minute citric acid solution etching on the surface will provide distinctive morphological information of the defect density, which can then be detected by using a scanning electron microscope at a moderate magnification. This method also can be applied to the quality control of sintered lead-rich dielectric glass layers, on plate glass, prior to deposition of an MgO coating over it.

Because of its selective reactivity, citric acid will attack the sites where MgO is chemically deteriorated, such as by localized formation of basic carbonate, and also reacts rapidly at the regions where pinholes and foreign phases exist. For that reason, very low defect density is found on those relatively stable panels after an initial 1 or 2-minute etch. On the other hand, very unstable panels rapidly reveal a high density of etched defects even after a 1 minute etch. Usually panels after a 2 to 3-minute etch will be sufficiently developed to reveal the defect density for the purpose of comparison on the quality of MgO films. The etch rate of MgO at room temper...