The external lead finish of plastic packages used until today is an electroplate of a Tin-Lead (Sn-Pb) alloy. This alloy has been the primary finish of electronic components for many years due mainly to the reliability of solder joints and ease of manufacturing. Sn-Pb plating for plastic packages usually consists of 10-20% lead.

Lead-free means less than 1000ppm Lead in over-all composition. The common Lead-free finishes on packages with leads are as follows:

• 100% Sn or Matte Tin
• Tin-Bismuth (Sn-Bi)
• Nickel-Palladium (Ni-Pd)

100% Matte Tin is the most common.

RoHS Compliant

The RoHS directive took effect on 1st of July 2006 and will become law in each member state of European Union (EU). This directive restricts the use of six hazardous materials in the manufacture electronic and electrical equipment.

RoHS restricts the use of the following six substances:

• Lead - Pb (Max 1000 ppm)
• Cadmium - Cd (Max 100 ppm)
• Mercury - Hg (Max 1000 ppm)
• Hexavalent Chromium - Cr VI (Max 1000 ppm) Poly Brominated Byphenyl -
• PBB (Max 1000 ppm)
• Poly Brominated Dyphenyl Ether - PBDE (Max 1000 ppm)

As can bee seen from the concentrations, RoHS compliant package is Lead-Free.

Green Package

Industry consensus defines a green package as a package that is RoHS compliant and additionally:

• Green Epoxy - Epoxy that can withstand 260 deg C soldering temp.
• Green Molding Mold Compound, Laminate, Solder resist - No brominated epoxy resin type as flame retardant  (Halogen-Free Cl or Br <900 ppm, Antimony-Free Sb2O3 <900 ppm)