Alloy Compositions
RoHS-Compliant Product Information
Nations around the world are passing strong legislation to restrict the use of hazardous substances in electronics. In Japan, the Ministry of International Trade has legislation to phase out the use of lead in electronics. In Europe, the European Union (EU) has the Wastes in Electrical and Electronic Equipment (WEEE) directive that includes a ban on lead-bearing solders scheduled to take effect in July 2006.
Altera is taking an industry leadership position and adopting technologies compliant with the restriction of hazardous substances (RoHS) directive to provide solutions that align with the industry requirements. In semiconductors, lead is mainly used in packaging as a part of the eutectic solder used as the surface finish for leaded packages and as the solder balls for ball-grid array (BGA) packages. Altera engineers have researched alternatives for lead compounds as well as the reliability concerns for these options, and have successfully qualified numerous RoHS-compliant packages. Details of the reliability qualification are available in the Lead-Free Package Qualification Report (PDF). Get more information on Altera’s RoHS-compliant product offerings and solutions.
RoHS-Compliant Alloy Compositions
| Table 1. RoHS-Compliant Alternatives |
|
Sn (1) |
SnAgCu (2) |
NiPdAu (3) |
| QFP (4) |
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| FBGA (5) |
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| SOIC (6) |
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Notes:
- Tin
- Tin-Silver-Copper
- Nickel-Palladium-Gold
- TQFP/PQFP/PLCC packages
- FBGA: FineLine BGA packages
- SOIC: Small Outline Integrated Circuit
For QFP packages, matte tin has been chosen as the RoHS-compliant alternative. This surface finish has been in high-volume use in the electronics industry for a number of years and its plating characteristics and reliability performance have been thoroughly tested. Matte tin offers excellent solderability and wetting with existing tin-lead solder processes and with lead-free soldering processes. Pure matte tin is a good choice from a manufacturing perspective because it is a single-metal alloy and has better manufacturability than plating of a multi-element alloy with a fixed composition.
For BGA packages, the eutectic solder balls have been replaced by Sn3%Ag0.5%Cu solder balls as the RoHS-compliant alternative. The microstructure of the SnCuAg alloy consists of an Sn-matrix containing fine Cu6Sn5 particulates ranging in size from 0.005 µm to 0.05 µm, and larger (> 2,000 µm) rod-like Ag3Sn precipitate particles. This microstructure strengthens the SnCuAg alloy through a precipitate dispersion alloy strengthening mechanism and gives it superior solder fatigue and creep resistance properties compared to eutectic solder or other lead-free alternatives. This alloy has also demonstrated excellent compatibility with existing tin-lead solder reflow processes and with lead-free soldering processes.
For SOIC packages, NiPdAu plating finish is offered as the RoHS-compliant alternate solution. This finish has been used in high volumes for SOIC, SSOP and TSSOP packages in the industry and is available as pre-plated lead frames through major lead frame suppliers. This surface finish has demonstrated excellent solder joint reliability and compatibility with eutectic and lead-free solders.
For additional information regarding RoHS-compliant applications in the industry, please visit the About RoHS-Compliant Devices page.
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