Packaging and assembly

Which correctly describes a feature of QFN (Quad Flat No-lead) packages?

  1. ALong leads extend outward from all four sides of the package
  2. BA small package with no protruding leads, with electrodes on the four edges of its bottom
  3. CSolder balls are arranged in a grid over the entire bottom
Show answer and explanation

Answer: B. A small package with no protruding leads, with electrodes on the four edges of its bottom

A QFN has no leads sticking out of its sides; instead, electrodes are exposed around the edges of its bottom. It is small and thin, often has a heat-dissipating electrode (thermal pad) in the center of the bottom, and offers excellent electrical and thermal performance.

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More Packaging and assembly questions

  1. What is the step called that attaches and fixes the chip at a set position on a lead frame or substrate?
  2. What is the step called that grinds the back side of a wafer before dicing to thin it and make the package thinner?
  3. 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?
  4. In wire bonding, what is the main reason gold (Au) wire has been increasingly replaced by copper (Cu) wire?
  5. Which symbol denotes the thermal resistance from the chip junction to the surrounding air, indicating a package's heat-dissipation performance?