THAT Corporation's RoHS Policy
All new products introduced since the start of 2004 are available
only in RoHS-compliant packages. THAT's RoHS-compliant packaging is compatible
with both conventional (Sn-Pb) soldering as well as most lead-free
solders. All pre-existing products are now available in lead-free (RoHS-compliant) packages.
About Lead in Electronic
Assemblies
Many countries have determined that lead (Pb)
in electronics assemblies can pose an environmental hazard when such
assemblies are scrapped. This is a large part the European RoHS
initiative. Japan and others have restricted the use of lead as well. These countries have set dates after which
lead will no longer be allowed in electronics assemblies. On the other hand, the USA and many other countries have not taken
this action.
Where Does The Lead Come From?
Until recently, most electronic components have tin-lead (Sn-Pb)
alloy as a surface finish or plating on their leads ("legs"
or "pins") and contain trace amounts of Pb in the gold wires
that internally attach the silicon die to the IC legs. Semiconductor companies, like other component makers, must
offer Pb-free versions of their products or face being "designed
out" of electronics products sold in the Pb-free countries.
Why Do Semiconductors use Lead?
The plating (conventionally tin-lead, abbreviated Sn-Pb) on the
device legs prevents the underlying leg material (usually copper) from corroding before
and after being soldered into the printed circuit board (PCB). The
lead in the plating (and in the solder) lowers the melting point of
the plating and solder, reduces migration of the tin before and after
soldering, and assists in forming a solid electro-mechanical joint
between the IC and the printed circuit board (PCB).
Eliminating Lead
To eliminate lead in electronic assemblies, it must be eliminated
from the solder as well as in the components themselves. For
integrated circuits, this means eliminating lead from the plating used
on the IC's legs. There are several ways to accomplish this, and THAT
has selected different leg plating methods based on finish options for
each of our packages as offered by our packaging vendors. See RoHS
Finishes for more details.
Trace amounts of lead as impurities are also found in the gold
wires that internally connect the active conductors ("pads")
on the silicon die to the IC leads. According to recent environmental
legislation in Europe and Asia, the amount of lead in this area may
not exceed the limits required of a particular "lead free"
standard.
Where Must Lead Be Phased Out?
The following countries that have announced Lead-Free initiatives
and target dates.
European Union - Restriction of Hazardous Substances (RoHS)
Effective 1 July 2006. Bans the use of Cadmium, Hexavalent Chromium,
Lead (Pb) Lead (Pb), Mercury, PBB (Polybrominated Biphenyls), and PBDE
Polybrominated Diphenyl Ethers) in electronic products. RoHS includes
banned material exemptions on some products and applications.
Japan - White Goods Recycling Act… Established lead reduction
targets in 2001.
China - Proposal to adopt legislation similar to EU RoHS Directive
with China’s " Management Methods". Released by the
Ministry of the Information Industry in March 2004 with effective date
1 July 2006.
USA - Several states (e.g., California and Massachusetts) are
considering bans on the same list of materials and potentially others.
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