Silver Migration and the Reliability of Pd/Ag Conductors in Thick-Film Dielectric Crossover Structures
ABSTRACT The relative performance characteristics of thick-film Pd/Ag conductors (0-34% Pd) for dielectric crossover structures in hybrid microelectronic circuits are described. The materials were supplied from Du Pont and Engelhard. The experiments involved waterdrop (WD) tests and temperature-humidity-bias (THB) tests at 90°C, 90% RH, and a dc bias of 5-50 V applied between the conductor electrodes for periods up to 1000 h. WD tests showed that the rate of Ag migration decreased by approximately 100 times as the Pd content in the conductor was increased from 10%-19%. However, the results of these tests were considerably scattered for electrodes of high Pd content. In addition, no conclusive results could be reached on the effect of the substrate or various encapsulants on the rate of migration. The rate of migration under THB conditions was considerably lower (10-4times) than that under the water-drop tests. Surface migration was found to be the dominant mode of failure in dielectric crossover structures. The rate of migration increased with the increasing voltage gradient. When the voltage was increased it caused an abrupt change in the capacitance and isolation resistance. The migration was more pronounced on the surface of bare alumina substrates than on substrates covered with a dielectric layer. Finally, a Du Pont 9137 glass encapsulant was found to be effective in preventing silver migration under THB conditions while an ESL 240 SB encapsulant enhanced the rate of migration.
- Journal of The Electrochemical Society - J ELECTROCHEM SOC. 01/1997; 144(5).
- [Show abstract] [Hide abstract]
ABSTRACT: For many years, direct bonded copper (DBC) substrates have proved to be an excellent solution for electrical isolation and thermal management of high-power semiconductor modules. However, in this study we detected a copper residue on the surface of DBC alumina, presumably a result of pattern etching even in industry. As is known, growth of metal dendrites could be observed with the assistance of electric field, temperature, and humidity. Metal dendrites normally grow from the cathode to anode. Silver and copper are two kinds of metals susceptible to migration. In this work, copper dendrites could be formed at 400°C and 50 V/mm between conductors. These dendrites may impact the reliability of DBC in power electronic applications. Therefore, the formation of copper residue is an interesting phenomenon for etched DBC and warrants further attention in the future.Journal of Electronic Materials 01/2011; 40:1-7. · 1.68 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: We have studied on the usage reduction and anti-migration properties of newly formulated lead-Free (Bi-based) Ag/Frit modified address electrode (hereinafter VE electrode) systems in PDPs (Plasma Display Panels). It is thought that their high performance such as anti-migration and the cost-competitiveness without any loss of performance in paste, process and luminous efficacy are originated from the optimum controlling of Ag/Frit weight ratio and low specific gravity by low Ag contents, respectively. Currently, lead-free VE electrodes are being applied as main electrode materials of PDP panels fabricated by SDI photo-imageable patterning process including ultra-fine resolution models.SID Symposium Digest of Technical Papers 01/2008; 39(1).