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Most plastic and wafer level packages are currently available as lead-free. Commercial metal can packages are now available as lead-free.
The Issue
Due to environmental concerns around the world, lead-free solutions in electronic components and systems are being implemented within the semiconductor and electronics industries.
National Semiconductor Corp. strives to minimize the amount of disruption that the switch to lead-free products might entail. We look forward to working with our customers to provide you with the most cost-effective and reliable lead-free packaging solution for your needs.
National Semiconductor's Action
Currently National is an active participant in several industry consortia addressing lead-free processing. These groups are evaluating lead-free solder alloys with lead-free components and printed wiring board finishes. Several of the lead-free solder alloys being proposed require a maximum reflow temperature higher than the current peak temperature for Sn/Pb, which is between 220-235oC.
Impact of 260°C Peak Reflow
One major impact on the packaging industry will be the higher reflow temperature required for lead-free assembly, with 260oC often mentioned as the upper target. The high temperature ensures that all the components on a fully populated board will reach the melting temperature of the lead-free solder. A majority of plastic packages will have difficulty meeting such a constraint at JEDEC-defined moisture sensitivity levels 1 and 2. Currently, certain small packages such as SOP (Small Outline Packages) and TSSOP (Thin Shrink Small Outline Packages) can withstand the thermal strain without suffering from interfacial delamination, popcorn-induced cracking, or warping. However, larger packages will not meet this requirement. Their JEDEC moisture sensitivity level classification will most likely be downgraded by as many as two levels
Packaging | Lead-Free Status | Impact to Customers | Tin Whiskers
European Dir. Compliance | Industry Consortia | Questions & Answers | Literature
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