Packaging and assembly

In reflow with lead-free solder (Sn-Ag-Cu), which is closest to the peak temperature that parts experience?

  1. AAbout 500 °C
  2. BAbout 100 °C
  3. CAbout 245 to 260 °C
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Answer: C. About 245 to 260 °C

Sn-Ag-Cu lead-free solder melts at about 217 to 220 °C, and reflow peaks at about 245 to 260 °C. Because this is hotter than with traditional tin-lead solder, packages and parts must withstand this temperature, and measures against moisture-induced damage became important.

  • A. About 500 °C would damage package resin and the like.
  • B. Lead-free solder does not melt at about 100 °C.
  • C. Correct. The peak is about 245 to 260 °C.
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