Chip Resistor Corrosion

SEM Lab, Inc. has seen the same type of resistor failures repeatedly since ~ 1997 when we were founded. The trigger appears to be the local environment where the resistors are deployed, for example ...

The problem, sulfur pollution and corrosion of silver, is illustrated in Fig. A and explained thoroughly in references [1] & [2]. The resistors increase in value and eventually fail open.

Corrosive Attack at Edges of Termination
Fig A - Illustration of corrosive attack of edges of termination. Gaseous H2S or COS is the likely source of sulfur [1].

References

[1] Craig Hillman, Joelle Arnold, Seth Binfield, Jeremy Seppi, "Silver And Sulfur: Case Studies, Physics, And Possible Solutions", DfR Solutions, College Park, MD, USA, 2007, email - askdfr@dfrsolutions.com, http://www.dfrsolutions.com/uploads/publications/2007_10_silver_and_sulfur.pdf. link

[2] Marie Cole et al, "Harsh Environment Impact On Resistor Reliability", SMTA International 2010 Conference Proceedings, http://researcher.ibm.com/researcher/files/us-kleinl/Resistor_Harsh_Environ_final_SMTAI2010.pdf.