IONIC CONTAMINATION EXTRACTION EFFECTIVENESS AND CORRELATION OF ANALYSIS METHODS
Authors: Pravin Sequeira, Kantesh Doss, Arnold Hogrefe, Minh Nguyen Company: Jabil Date Published: 10/24/2010
Abstract: In an attempt to assess Electro-Chemical Migration (ECM) risk, we plan to develop an index that is able to determine Time-To-Failure of Printed Circuit Board (PCB) assemblies relative to the required conditions – ionic contamination, electrical bias, moisture, and soluble metal ions. Quantitative assessment of ionic contamination will involve determination of extraction effectiveness, and development of an approach to characterize contamination (type and quantity) on PCB assemblies. The first phase of this study (the scope of this paper) will investigate the ability to extract ionic contaminants from various substrates and surfaces, and to determine the correlation between some of the available analysis methods. The plan includes application of known quantities of anions to test substrates, and subsequent extraction and analysis using established methods. The extracts will then be analyzed to quantitatively determine the amount of extracted species, and thereby the extraction efficiency. The study will encompass six inorganic and five organic acid anions applied at concentrations close to the industry standard maximum per square inch for each anion. The test substrates will include ceramic, FR4, FR4 with solder mask, glass, copper, ENIG, tin-lead HASL, and SAC HASL. The tools for analysis will consist of localized and bag extraction methods, Ion Chromatography, and Conductivity testers.