Pb-free
Strategy
Orister's
Quality Assurance Organization develops, coordinates and champions strategic
Quality Initiatives throughout Orister, our foundries, sub-contractors and business
partners. Orister's QA organization's mission is to enable Orister to design,
develop, manufacture and deliver product to our customers with World Class Quality
and Reliability that meets and exceeds our customer's expectations.
RoHS = Restriction of the use of certain Hazardous Substances
The directive 2002/95/EC
of the European Parliament and of the Council of 27th January 2003 on the RoHS
in electrical and electronic equipments entered into force on 13th of February
2003. The aim of this directive is to ban heavy metals (Lead, Mercury, Cadmium,
Hexavalent Chromium, …) and two brominated compounds (PBB and PBDE). The directive
will be applicable throughout EU by 1st July 2006. The Orister is fully in line
with European RoHS. Therefore, once converted to Pb-free, Orister devices are
RoHS compliant.
Lead-free Conversion Program
The RoHS directive being
applicable by July 1, 2006, Oristerhas already converted 100% of the packages
and is able to deliver all products in leadfree version. Among the different
technical solutions available, three technologies have been selected taking
into account their maturity, Oristermanufacturing feasibility and capacity and
market acceptance. This choice will allow to drive the change in a timely and
transparent manner. The conversion program applies both to internal and subcontractor
production lines.
Pb-free Plating Selection
Orister initially considered
the following candidates for Pb-free plating: SnAg, SnBi, SnCu, NiPdAu, and
matte tin. The properties of each of these lead finishes can be summarized as
follows:
SnAg
- good solderability and mechanical properties
- high material cost
- need for extensive plating bath control procedures
SnBi
- widespread use in Japan
- tends to be brittle
- complex plating control
- concern over backward compatibility with Pb-containing solders
SnCu
- relatively inexpensive
- good solderability
- small changes in alloy composition could cause large changes in eutectic temperature
- difficult to accurately control plating composition
- lead finish not compatible with Alloy 42 leadframes
NiPdAu
- simplified assembly process
- unpredictable high cost
- limited number of vendors
- concerns with cracking of the plating at bends, soldering, wire bonding, molding
- not compatible with Alloy 42 leadframes
Matte tin
- extensive industry experience with implementation
- well established history of reliability
- good soldering characteristics over a wide range of leadframes
- relatively low cost
- no binary alloy composition issues to manage
- no issues with availability
- compatible with Pb-free and Pb-containing solders
- melting point of 232°C fits well with the 230°C to 260°C heat reflow profile
of today's components
For the reasons listed
above and since Orister had a long history of using matte Sn for specific
applications, a matte Sn process solution was the preferred choice for the
vast majority of products requiring a Pb-free external finish.
