PCB007 Magazine

PCB-July2017

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July 2017 • The PCB Magazine 79 ed good shear strength and comparable thermal cycling survivability to HASL; and 3) Pd content from a standard ENEPIG finish is acceptable for high reliability in small solder joints (1.5−2.5 mil). Bill ended by calling for additional discus- sions on two points: 1) Material and process de- tails such as gold thickness, solder mask thick- ness, and solder volume are critical factors to very small solder joints, and 2) Gold at 3% in a solder joint may have been a factor in crack initiation, but thermal cycle failures are in the bulk solder joint. It's Time to Improve Component Standards and Measurement Joe Russeau, president of Precision Ana- lytical Laboratory, asked the rhetorical ques- tion "should the industry care about compo- nent cleanliness?" and presented the results of a study by the ad hoc Cleanliness Team. The team member companies included IEC Elec- tronics, Corfin Industries, Secure Components and Precision Analytical Laboratory, and fo- cused on understanding the impact of compo- nent cleanliness on reliability. The team has completed the first two of the four phases of the study: Phase I—Printed Circuit Board (PCB) Cleanliness; Phase II—Component Cleanli- ness; Phase III—Printed Circuit Board Assem- bly (PCBA) Cleanliness; Phase IV—Reliability Cleanliness Limits. Joe's call to action was to continue the dia- log in the industry on the following topics: • It's time to improve component cleanliness standards and measurement – Start the discussion (Why should industry care?) – What is meant by "cleanliness"? • What are the current industry techniques used for measuring ionic "cleanliness"? Resistivity of Solvent Extract (R.O.S.E) – Ion Chromatography – GEIA-STD-0006, Requirements for Using Robotic Hot Solder Dip to Replace the Finish on Electronic Piece Parts – Data Comparison Study (R.O.S.E. vs. IC) • Where do we go from here? Fresh Perspective on Test William Graver, senior analyst with Nation- al Technical Systems (formerly Trace Laborato- ries), presented the thought-provoking ques- tion, "Is test an unnecessary evil, or a life-saving necessity?" William walked through a number of major reliability concerns in today's environ- ment, and presented some graphic examples of catastrophic reliability failures. Two major fail- ure modes were reviewed in the form of case studies. The first study was on via-pad separa- tion in rigid-flex PCBs, which exhibited a 25% REVIEW OF THE 2017 IPC RELIABILITY FORUM Figure 8: Bill Fox, Lockheed Martin. Figure 9: Joe Russeau, Precision Analytical Laboratory.

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