Why RoHS?

  • Legislation: European Union has established a phase-out date of July 1, 2006 for Pb in electronic products with some exceptions.
  • RoHS (Restriction on Hazardous Substances) and WEEE (Waste Electrical and Electronic Equipment ) directives prohibit the usage of Lead , Mercury, Cadmium, Hexavalent Chromium, PBB and PBDE.
  • Customer requirement: Sony and other companies have initiated a green procurement process which required all suppliers to provide green product before certain deadlines.

Definitions

  • Lead-free package

    • Lead-free package is ROHS compliance
    • Removal of lead (Pb) in package
  • Green package

    • Removal of lead (Pb), antimony trioxide (Sb2O3) and brominated flame-retarding compound from encapsulants and substrates
  • Maximum levels allowed

    • (Pb) < 1000 ppm
    • Halogens (Cl, Br) < 900 ppm
    • Antimony < 900 ppm
  • Package Materials Impacted

Part No.CategoryDensityI/OVdd / VddqSpecStatus*
Leadframe Lead Finish Removed (Pb) from solder
  Mold compound improve moisture sensitivity
  Die attach epoxy Improved adhesion and moisture resistance
Area Array Die attach epoxy Improved adhesion and moisture resistance
  Substrate Improve moisture sensitivity
  Solder mask Improved adhesion and moisture resistance
  Mold compound Improve moisture sensitivity
  Solder ball Removed (Pb) from solder ball
Flip Chip Solder bumps Removed (Pb) from solder

Solutions

  • Terminations

    • Lead plating from Sn-15Pb to Matted Sn.
    • Pre-plated lead frame (PPF) with Ni/Pd/Au finish.
    • Solder ball from Sn-37Pb to Sn-4.0Ag-0.5Cu or Sn-3.0Ag-0.5Cu, Sn-1.0Ag-0.5Cu
  • Mold compound and Substrate

    • Moisture resistance for 260C reflow temp.
    • Phosphorous free
    • Halogens, Sb2O3 free. (Green package only)

Lead-free package Qualification

  • Reliability Test Items:
    • Precondition:
      MSL Level III, 260 degree C
    • Temperature Cycle:
      -65℃~150℃/1000 cycles
    • High Temp. Storage:
      150/1000 hours
    • Temp Shock Test:
      -65℃~150℃/100 cycles
    • Pressure Cooker Test:
      121℃/100% RH, 15 PSIG, 168 hours.
    • Other Tests:
      Solderability, Lead finish composition, Whisker test, etc

Package Lead Free IR-Profile Samples

Package ThicknessVolume mm3 <350Volume mm3 350 -2000Volume mm3 >2000
<1.6 mm 260 +0 °C 260 +0 °C 260 +0 °C
1.6 mm -2.5 mm 260 +0 °C 250 +0 °C 245 +0 °C
≥2.5 mm 250 +0 °C 245 +0 °C 245 +0 °C


Figure Classification Profile

Nuvoton Lead-free and RoHS Marking Symbols

  • We will print lead-free and RoHS symbol on bar code label to identification of lead-free assemblies.

FAQ

  • How does Nuvoton define “lead-free”, “ROHS compatible” and “Green”?
    Lead-Free: Nuvoton's terms “ Lead-free” or ”Pb-free” mean semiconductor products that are compatible with current ROHS requirements for all 6 substances. Green: mean lead-free and free of Bromine (Br) and Antimony (Sb) based flame retardants.
  • How can I find out if a specific device is lead-free or Green, or when it will be?
    Nuvoton product content website shows the current production status, package finish, and lead-free and Green status of the individual parts.
  • Will lead-free or Green devices be more expensive than Pb-based devices?
    Pricing is determined by product marketing. Conversion to lead-free, in and of itself, is not planned to result in price changes.
  • If a device is converted to lead-free, will Nuvoton continue to supply the Pb-based part?
    Nuvoton is encouraging all customers to convert to lead-free for all product use. Please contact with our sales for the special request of leaded products.
  • Will Nuvoton change the part numbers?
    Yes, product part number will be changed for lead-free part.
  • In what way would a lead-free or Green device influence my board’s functionalities or my application?
    None expected.
  • Are lead-free parts compatible with a Pb-based soldering process?
    Our lead-frame based lead-free products are backward compatible with leaded soldering process. However, for BGA type lead-free products, it is not backward compatible with leaded soldering process. Solder joint reliability can be a concern.
  • What is being done to mitigate tin whisker growth?
    We have chosen matte tin as the lead finish for all lead-free products. The package is annealed within 24 hours at 150°C for 1 hour after lead plating. This is the industry-accepted method for mitigating tin whisker growth.

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