Advanced packaging (3D and chiplets)

In flip-chip connections, what is the main advantage of using copper pillars (Cu pillars) instead of solder balls?

  1. ABumps can be made larger to increase contact area
  2. BBump pitch can be narrowed, and electrical and thermal conduction are also excellent
  3. CSoldering becomes entirely unnecessary
Show answer and explanation

Answer: B. Bump pitch can be narrowed, and electrical and thermal conduction are also excellent

A Cu pillar bump is a copper pillar with a small amount of solder on its tip. Unlike solder balls, it does not melt and spread sideways, so the bump spacing (pitch) can be narrowed and many terminals placed. Copper conducts electricity and heat well, which also helps current capacity and heat dissipation.

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  3. Which is a correct advantage of glass substrates, being considered in place of organic materials for next-generation large package substrates?
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