SMT007 Magazine

SMT007-Jan2020

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JANUARY 2020 I SMT007 MAGAZINE 13 • Amendment 1 to J-STD 006C was published in October 2017 to incorporate new alloy list- ings, the statements regarding rare earth elements, and the expansion of control ranges of nominal compositions Solder Alloy Inclusion in the Standard Requirements to list a solder alloy in the J-STD-006 include: • All elements, including dopants, shall be disclosed • All elemental dosages, including dopants, shall be provided • Analytical methods to identify and confirm the presence and quantity shall be provided It should be noted that all elements herein refer to all intentionally introduced elements or included in the manufacturing process of an alloy composition for a purpose, use or expected function, rare earth or otherwise (e.g., La, Ce, Nd, Mn, Ge, etc.) regardless of dosage (e.g., 88 wt% or 0.01 wt%); that is, elements in an alloy composition that are not introduced by design are impurities. Upcoming Challenges In our recent past meetings, I have chal- lenged the task group to address four ques- tions: 1. How can we make J-STD-006 document more useful, more complete, more informative, and more practical to the industry (i.e., suppliers, users, or any interested party)? 2. Which area(s) should be added? 3. Which area(s) should be expanded? 4. What are the priorities? To this end, one of the recurring issues that was brought up in our task group meetings is dop- ant vs. impurities. As more new alloys are being developed with intentionally added dopant(s) in a small weight percentage, J-STD-006 bears the responsibility to provide a guide. Framework Efforts on Dopants vs. Impurities Updating solder alloy impurities remains a challenge. Differentiating dopants from impu- rities drives another level of effort. I have laid out the skeletal framework that is to be consid- ered in three distinct categories of elements. 1. Current impurities elements (Table 3-2). • E.g., Ag, Cd, Pb, Al, Cu, Sn, As, Fe, Zn, Au, In, Sb, Bi, Ni 2. Additional elements to be considered. • E.g., Phosphorus (P), sulfur (S), others • It is worth noting that QQ-S-571F (Federal specification: solder, electronic) limits P at 0.010 wt% and S at 0.005 wt%, but J-STD-006 makes no call on these two elements, which could potentially affect the properties and behavior of a solder alloy 3. Dopants being used in alloys that are listed in the current impurity table. • E.g., Ni, others To move forward to the next stage of devel- opment of J-STD-006, the issue is requested to be addressed. This will be a daunting task, demanding substantial efforts and affecting suppliers, users, and the industry overall.

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