Folks,
I was at APEX 2013 San Diego this past week. San Diego is a great venue for the show, but I always forget how cold it can be (55-65°F) this time of year. The folks at iConnect 007 interviewed me at the show; the topic was lead-free reliability and has cost for consumer electronics been demonstrated. You can see the interview here.
These are topics I think about often, so let’s discuss them a bit. First, let’s consider reliability. RoHS was enacted on 01 July 2006, more than 6 ½ years ago. Each year more than $1 trillion-worth of electronics are made, therefore, in this period of time, something over $3 trillion worth of consumer electronics have been manufactured. There have been no “the sky is falling”-type of reliability issues in this time. How can I say this? Well, my office at the Thayer School of Engineering at Dartmouth is across the hall from the IT (information Technology) Dept. They purchase all of the millions of dollars worth of PCs, printers, displays etc. that Thayer uses. Several years ago (say early 2011) I stopped by when most of the department was in and cheerfully asked if the reliability of the equipment they purchase has gone down since lead-free assembly was enacted. They asked me in unison, “What’s lead-free assembly.” After I explained what lead-free assembly was, they confirmed that they have noticed no changes in reliability. Since RoHS, my family has purchase about 100+ electronic devices, a few have had reliability problems, about as many as in the past. Most were attributed to hard drive fails. Of the scores of friends and colleagues I have, no one has ever commented that they have noticed an increase in electronics fails. So, my conclusion is that consumer product reliability is not "practically" worse if my family and these many other folks haven’t noticed it.
I have made an informal study of reliability data of lead-free vis-a-vis tin-lead solders published in papers. A statement from Rockwell Collin’s JCAA/JGF-PP No Lead solder Project: -55C-125C Thermal Cycle Testing Final Report sums up my overview conclusion nicely: “Test vehicles assembled with lead-free materials (notably tin-silver-copper) exhibited lower reliability under some test conditions.” Nay sayers might be quick to suggest that this statement says that lead-free is no good. However, the statement could be reworded to say: “In considerably more than half of the test conditions, test vehicles assembled with lead-free materials had higher reliability." Counting the comparisons in the Rockwell Collins paper shows lead-free better in 51 cases, tin-lead better in 31 cases, and one draw. However, it is disturbing that a small percentage of lead-free assembled test vehicles had much much worse reliability than tin-lead test vehicles. This later information makes me believe that lead-free is not yet ready for mission-critical, high-reliability, long-life products. These small numbers of much poorer reliability assemblies must be understood and corrected before lead-free is ready for mission-critical prime time. The much shorter life cycle of today’s consumer electronics may also mask this concern.
What about cost? I don’t at all want to minimize the expense that many went through to go lead-free and RoHS compliant. In about 2007, one of our colleagues estimated that it cost the electronics industry $20 billion to become RoHS compliant. I think this number is low, but, from a consumer’s perspective, there has been no cost hardship. The price of a PC continued to go down during and after RoHS implementation, as shown in the figure below. While performing my non-scientific survey of co-workers, family, and friends on reliability, I also asked about cost. All agreed, electronics are cheaper than ever.
Challenges still exist, even in consumer electronics with the Head-in-Pillow, Graping, non wet opens, and other defects. However, we can all purchase lead-free, RoHS compliant products at a reasonable cost and reliability.
Cheers,
Dr. Ron
The source for the image is :http://thomaslah.wordpress.com/2010/02/03/apple-and-intel-defying-gravity/
Over the years, solder alloy choices have been pretty stable. In the last century, SN63 and SN62 could be found at any company making any kind of electronic device, and both alloys were the backbone of every company making solders.
Indian electronics manufacturers and solder users. This info is for you.
Most wave soldering solders have low or no silver. So, about 3% of the 10,000 tons of SMT solder, or 300 MTs of silver, are used in electronics. This is about 1.5% of the 22,000 MTs of silver produced each year. Silver use in electronics does not make anyone’s list of top silver usage.
So electronics solder use since RoHS has not caused tin use to increase, nor is it a significant factor in silver use. Therefore it is highly unlikely that electronics' use of tin or silver has been a prime driver in their stunning price increases in 2011.
Folks,
Based on 
We don't know, however, if tin whisker mitigation techniques were used. In a mission critical application, such as this, it would appear unwise to use RoHS-compliant electronics, especially since they are not required for automobiles. In other words, autos are exempt from RoHS. Let me be very clear, from a tin whisker perspective, I am uncomfortable with RoHS-compliant tin plating in mission critical applications. Much more work needs to be done before such tin plating should be used in mission critical applications.
Content on the Solder Joint Reliability of a Pb-free PBGA Package.” Both projects evaluated lead-free thermal cycle reliability as a function of silver content and compared the results to SnPb reliability.
Some have argued that the recycling requirement exacerbates the rampant counterfeit component crisis. I am sympathetic to this argument, but the counterfeit component calamity must be solved another way. With the volume of scrap electronics that exists, the world needs safe and effective recycling, as can be seen in the accompanying photograph (National Geographic January 2008).
Lately I have been researching a bunch of things, one of my favorite topics being soldering alloys. For a long time most solder (nearly all) was comprised of tin-lead eutectic alloy. Everyone was very comfortable using this alloy until RoHS and other changes in regulations started to tip the scales in favor lead-free alloys, requiring a new approach to soldering materials and processes. The industry, since then, has tended toward using tin-silver-copper (SAC) alloys of various compositions; however none have lived up to all of the properties tin-lead solder offered. In fact, one of the most disruptive characteristics of SAC alloys has been the increased temperature required for reflow, therefore the increased temperature requirements for components and boards.
As more and more waste electronics becomes RoHS-compliant, the amount of toxic material that these people are exposed to will become less and less. It still shocks me that, when I point out this benefit, a person comments something like this:
The last number is detection (D) of a potential fail. A”10” would suggest that the detection of a potential fail is either not performed or not possible. A “7” is a manual detection approach that may not be reliable, whereas a “2” is 100% effective potential failure inspection.
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