Pb-free
Strategy
Orister' 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.