Electronics Forum | Wed Mar 04 11:16:25 EST 2009 | patrickbruneel
From your description of the problem first reduced SIR to dead short is exactly what happens with dendrite growth. What is needed to form them is low bias voltage (10 volt range is ideal with low current), a surface, 2 conductors (containing tin), io
Electronics Forum | Mon Nov 22 17:32:34 EST 2004 | davef
Assemblers often assume that the board and component suppliers provide them with clean product. This was not a problem when everyone used water washable fluxes, because the water washing used to clean the flux residues also cleaned the board and com
Industry News | 2010-10-27 18:18:54.0
STI Electronics, Inc., a full service organization providing training, electronic and industrial distribution, consulting, laboratory analysis, prototyping, and small- to medium-volume PCB assembly, announces that it has been awarded a Global Technology Award in the category of Contract Services
Technical Library | 2009-10-14 21:17:47.0
Electrochemical migration (ECM) is defined as the growth of conductive metal filaments across a printed circuit board (PCB) in the presence of an electrolytic solution and a DC voltage bias. ECM, also known as dendritic growth, is a critical issue in the electronics industry because the intermittent failure behavior of ECM is a likely root-cause of the high occurrence of field failures identified as no trouble found (NTF)/could not duplicate (CND)
Technical Library | 2023-04-17 17:05:47.0
In an ideal world, manufacturing devices would work all of the time, however, every company receives customer returns for a variety of reasons. If these returned parts contributed to a fail, most companies will perform failure analysis (FA) on the returned parts to determine the root cause of the failure. Failure can occur for a multitude of reasons, for example: wear out, fatigue, design issues, manufacturing flaw or defect. This information is then used to improve the overall quality of the product and prevent reoccurrence. If no defect is found, it is possible that in fact the product has no defect. On the other hand, the defect could be elusive and the FA techniques insufficient to detect said deficiency. No-clean flux residues can cause intermittent or elusive, hard to find defects. In an attempt to understand the effects of no-clean flux residues from the secondary soldering and cleaning processes, a matrix of varying process and cleaning operation was investigated. Of special interest, traveling flux residues and entrapped residues were examined, as well as localized and batch cleaning processes. Various techniques were employed to test the remaining residues in order to assess their propensity to cause a latent failure. These techniques include Surface Insulation Resistance1 (SIR) testing at 40⁰C/90% RH, 5 VDC bias along with C32 testing and Ion Exchange Chromatography (IC). These techniques facilitate the assessment of the capillary effect the tight spacing these component structures have when flux residues are present. It is expected that dendritic shorting and measurable current leakage will occur, indicating a failing SIR test. However, since the residue resides under the discrete components, there will be no visual evidence of dendritic growth or metal migration.
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