RoHS Compliant and Lead Free Assembly Compatible Materials

Nelco PCB Materials are RoHS Compliant

• RoHS Compliance Letter for Nelco Materials (more)
• REACH Letter for Nelco Materials (more)
• Perfluorooctane Sulfonates (PFOS) Letter (more)
• Article from Compliance.co.uk regarding the WEEE Directive (more)
• Internal testing has shown all Nelco materials to be RoHS compliant. Following are some additional independent laboratory test results for key materials.
• Mercurywave™ 9350 Microwave Performance, Modified Epoxy RoHS Test Report
• N4000-2 Multifunctional FR4 Epoxy RoHS Test Report
• N4000-6 / N4000-6 FC High-Tg Multifunctional FR4 Epoxy RoHS Test Report
• N4000-7 Low-CTE Multifunctional Epoxy RoHS Test Report
• N4000-11 Low-CTE, High-Tg Multifunctional Epoxy RoHS Test Report
• N4000-29 Lead-Free, High-Tg Multifunctional Epoxy RoHS Test Report
• N4000-12 High-Speed, Low-Loss, Lead-Free Compatible Epoxy RoHS Test Report
• N4000-13 High-Speed, Low-Loss Epoxy RoHS Test Report
• N9000 PTFE / RF Microwave Materials RoHS Test Report

Nelco Provides Several Lead Free Compatible Materials

A variety of lead free assembly compatible materials are available, including those with high Tg, high thermal reliability, low expansion and halogen free formulations.

• The new Nelco Material Selection Guide provides comparative materials overview including CAF and lead-free designations for Nelco electronic materials including notations as to the lead free compatible materials
• Nelco Lead-free electronic material listing and information (more)
• Lead-Free Technical Papers:
• Evaluating Laminates for High Temperature Assembly
  By Silvio Bertling
  As printed in The Board Authority, September 2005
• PWB Dielectric Substrates for Lead-Free Electronics Manufacturing
  By Douglas Leys and Steven P. Schaefer
  As presented at IPC Expo 2003

Qualities to consider when choosing a lead-free material:

Glass transition temperature (Tg), coefficient of thermal expansion (CTE) and decomposition temperature (Td) are key data points to consider when choosing a substrate material for a lead free assembly compatible design.

• The Tg of a resin system is the temperature at which the material transitions from a rigid state into a softened state. Tg is the material property typically used by the industry to compare the thermal robustness of a laminate. Though a contributor to lead-free compatibility, Tg alone is not sufficient to indicate if a material is suitable for lead free applications.
• CTE is a measure of the material expansion below and above the Tg and generally expressed as parts per million (ppm). A lower CTE generally indicates increased plated through hole (PTH) reliability. A low CTE is a strong indicator of lead free compatibility and high temperature solder reliability.
• Td is derived by measuring the weight loss of the sample versus temperature. Td is important when assessing thermal survivability, particularly during high temperature lead-free processes. A material's decomposition temperature is the temperature at which the material weight changes by 5%.

September 15, 2009