Packaging and assembly

Which composition is widely used as lead-free solder to meet environmental regulations?

  1. ASn-Pb eutectic
  2. BSn-Ag-Cu system
  3. CHg-Au system
Show answer and explanation

Answer: B. Sn-Ag-Cu system

Since regulations such as the RoHS Directive restricted lead, Sn-Ag-Cu (SAC) solders based on tin, silver and copper have come into wide use. Their melting point is higher than that of conventional Sn-Pb eutectic solder, so reflow temperatures are also higher.

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More Packaging and assembly questions

  1. Which correctly describes a feature of QFN (Quad Flat No-lead) packages?
  2. What is the step called that attaches and fixes the chip at a set position on a lead frame or substrate?
  3. What is the step called that grinds the back side of a wafer before dicing to thin it and make the package thinner?
  4. What is the phenomenon called in which, when a moisture-laden resin package is heated in solder reflow, the moisture inside suddenly vaporizes and expands, cracking the package?
  5. In wire bonding, what is the main reason gold (Au) wire has been increasingly replaced by copper (Cu) wire?