RoHS war stories
eutectic solder for the terminations. uct assembly process. After a lengthy was a spliced reel, or the reel was made
5. During an inspection of a finished investigation, it turns out that a long up of “sweepings” put together by the
PCB subassembly, we were alerted time assembly line employee, in charge supplier or their distributor. An on-site
to the possible presence of Pb in the of installing cabling, had taken matters audit of the supplier did find some
solder. From a visual inspection, the into his own hands. He had purchased deficiencies in their processes, which
dull finish of Pb-free solder made a large quantity of cable ties, housed have since been corrected.
the one area of shiny solder very easy them at his station and added them to 3. An LCD was tested for RoHS compli-
to identify. After following up with the product himself!! ance. Every layer of the LCD was
XRF and confirming the result, the tested, along with each piece of plastic
manufacturer was contacted and their accessories and metal and all components—both
response was “Oh, I know that we did 1. Not knowing the chemistry of leather, the terminations and the body were
some re-working of the board with we were very surprised to detect a sig- tested. One chip component was found
leaded solder but since we worked so nificant chromium peak on the leather to contain lead by XRF testing. This
hard on the original RoHS conversion, of a holster when carrying out explor- was followed by cross-sectioning and
I didn’t think anyone would mind.” atory XRF testing. Why test a holster? SEM/EDX analysis, which confirmed
6. RoHS testing was completed for a It is not an electronic device—no power the presence of lead in the form of tin/
stacked die part. The part was failed cord, battery, solar cell or fuel cell. If it lead eutectic solder on the termina-
because the top set of solder balls were were being sold on its own then there tions. This information was fed to
SnPb 63/37. It was very embarrassing would be no question; however, when the supplier, who did not believe the
when the supplier pointed out that the it is placed in a box with an electronic allegation. First the report had to be
top part was a flip chip and thus the device, then is must meet criteria set provided and then the actual assembly
balls were exempt from the directive. forth in the RoHS directive. had to be provided before they would
We have since learned that at admit that they had made a mistake.
Finished products least one popular leather tanning
1. We have found Cr+6 as an anti- process uses Cr(VI). It gives leather a acknowledgements
fingerprint treatment on stainless steel suppleness not found in several other The authors would like to thank the sev-
refrigerators. It is transparent in that non-Cr(VI) processes. With chromium eral anonymous contributors who provided
specific application and came as a being detected, what is the next step? some very interesting examples that make
complete surprise. As it is applied over XRF cannot tell the difference between up a portion of this paper.
stainless steel that has a high Cr(0) chromium metal, Cr(0), Cr(II), Cr(III), Bev Christian would also like to thank
content, it is virtually impossible to test Cr(IV) and Cr(VI). The chromium in Mr. Benson Tendler, VP of hardware qual-
by screen testing. This was discovered the leather was further tested using the ity, for support of this work
by querying the supplier. UV-visible spectroscopic method as Mike Fry would like to extend great
2. After working with a client who had detailed in IEC 62321, latest edition
4
. thanks to Bruce Calder (president, Intertek
spent months converting their product The good news is that for one OEM Ageus Solutions), for giving him the
to RoHS compliance, we were conduct- the amount of Cr(VI) in a homoge- opportunity to work and succeed in this
ing XRF screening to see if anything neous material was never found to be industry, Walter Jager (VP of engineering)
failed inside the housing and on the greater than 250 ppm. for countless RoHS Q&A sessions, and
product’s extremities. A thorough 2. A Bluetooth headset was disassembled Bev Christian for being generous enough
screening of 100 scans was conducted and tested for RoHS compliance using to share the authoring of this paper.
and the product passed with flying an analytical XRF, as usual. One chip
colors. As an afterthought, the label on component was found to contain lead. references
the product that stated “RoHS Compli- A similar looking component else- 1. http://eur-lex.eu-
ant” was screened and found to have where on the small PCB did not con- ropa.eu/LexUriServ/LexUriServ.
had very high lead content. All their tain lead. The component was removed do?uri=CELEX:32002L0095:EN:HTML
work was rendered useless as the label from the board and cross-sectioned 2. Lars-Olof Wallin, “Are Scandi-
that boasted their work was the area of for examination in a SEM/EDX to navian Companies Ready for Lead free
non-compliance. determine whether the lead was there PCBs?”, Proceedings of APEX 2006,
3. The same scenario as above occurred is a form that was exempt – high lead Anaheim, California.
with a different client but this time, solder (unlikely in this application), 3. http://ec.europa.eu/environ-
with cadmium being the substance that lead glass frit (possible) or lead based ment/waste/weee/legis_en.htm
negated all the compliance efforts for ceramic (most likely). However, the 4. IEC 62321, 111/99A/RVC,
product conversion. lead was found only on the termina- Electrotechnical products - Procedures
4. Again, working with a client to screen tions of the component in the form of for the determination of levels of six
for RoHS compliance, the XRF scans eutectic tin/lead solder. regulated substances (Lead, Mercury,
performed on the product were not The device supplier was contacted Cadmium, Hexavalent Chromium,
producing any significant risks to com- and informed of the discovery. As in a Polybrominated Biphenyls, Polybromi-
pliance. It was only when the orange few other cases, it took some convinc- nated Diphenyl Ethers) found at: http://
cable ties were prepared for sampling ing to get them to realize that this was www.iec.ch/cgi-bin/procgi.pl/www/
that significant levels of cadmium were real. No root cause was ever found, but iecwww.p?wwwlang=e&wwwprog=pro-det.
exposed. As it turns out, the cable ties a few may be speculated—a reel ran out p&He=IEC&Pu=62321&Pa=&Se=&Am=
were not called out in the product on a placement machine and a reel of &Fr=&TR=&Ed=1
BOM, nor were they part of the prod- tin/lead parts was substituted, the reel
www.globalsmt.net Global SMT & Packaging – June 2009 – 13
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