Effect of surface finish material on printed circuit board for electrochemical migration

2008 ◽  
Vol 48 (4) ◽  
pp. 652-656 ◽  
Author(s):  
Bo-In Noh ◽  
Jong-Bum Lee ◽  
Seung-Boo Jung
Keyword(s):  
Surface Finish ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Electrochemical Migration ◽  
Printed Circuit ◽  
Finish Material ◽  
Effect Of Surface

A Comparison of Immersion Gold and Tin Surface Finishes on Sensing Electrodes for PCB Environmental Saltwater Concentration Sensors

2016 ◽  
Vol 2016 (1) ◽  
pp. 000557-000562
Author(s):  
Robert N. Dean ◽  
Frank T. Werner ◽  
Michael J. Bozack
Keyword(s):  
Surface Finish ◽  
Printed Circuit Board ◽  
Chemical Constituents ◽  
Low Cost ◽  
Circuit Board ◽  
Testing Environment ◽  
Printed Circuit ◽  
Sensor Performance ◽  
Sensing Applications ◽  
Surface Finishes

Abstract Printed circuit board (PCB) sensors using low-cost commercial printed circuit board fabrication processes have been demonstrated for environmental sensing applications. One configuration of these sensors uses exposed electrodes to measure saltwater concentration in freshwater/seawater mixtures, through monitoring the resistance between the electrodes when they are immersed in the saltwater/freshwater solution. The lowest cost commercial PCB processes use an immersion Sn HASL surface finish on exposed copper cladding, including the sensing electrodes. This commercial PCB process has been demonstrated to make an effective, low-cost, short-lifetime sensor for saltwater concentration testing. The Sn finish, however, may not be optimal for this application. Sn oxidizes, which can interfere with sensor performance. Additionally, Sn and Sn oxides are potentially reactive with chemical constituents in seawater and seawater/freshwater solutions. An immersion Au (ENIG) surface finish is certainly less reactive with the atmosphere and chemicals likely present in the testing environment. However, an immersion Au finish increases the cost of the sensors by 30% to 40%. To investigate if the possible benefits of the more expensive Au surface finish are worth the extra expense, a study was performed where identical PCB sensors were procured from a commercial vendor with their standard low-cost Sn HASL finish and with their standard ENIG surface finish. Both sets of sensors were then evaluated in concentrations of seawater and freshwater, from 0% to 100% seawater concentration, using freshwater samples from a natural freshwater source near the coast where the seawater was obtained. Testing demonstrated an insignificant difference in sensor performance between the Sn HASL and the ENIG coated sensing electrodes. The results of this investigation indicated that for applications where the sensors will not be used for long periods of time, the added expense of an immersion Au surface finish is not worth the added cost.

Electrochemical migration characteristics of eutectic SnPb solder alloy in printed circuit board

2006 ◽  
Vol 504 (1-2) ◽  
pp. 294-297 ◽  
Author(s):  
Shin-Bok Lee ◽  
Young-Ran Yoo ◽  
Ja-Young Jung ◽  
Young-Bae Park ◽  
Young-Sik Kim ◽  
...  
Keyword(s):  
Solder Alloy ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Electrochemical Migration ◽  
Printed Circuit ◽  
Snpb Solder ◽  
Eutectic Snpb

Humidity Threshold Model of Numerical Control Multilayer Printed Circuit Board for Electrochemical Migration

2014 ◽  
Vol 31 (4) ◽  
pp. 567-578 ◽  
Author(s):  
Chuanning Xie ◽  
Xiaoqi Tang ◽  
Jihong Chen ◽  
Bao Song ◽  
Jian Jin ◽  
...  
Keyword(s):  
Printed Circuit Board ◽  
Threshold Model ◽  
Numerical Control ◽  
Circuit Board ◽  
Electrochemical Migration ◽  
Printed Circuit
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