Advanced packaging (3D and chiplets)

Which correctly explains how copper electrodes are joined to each other in copper-dielectric hybrid bonding?

  1. ASolder is melted to connect the copper
  2. BThe copper is stuck together with adhesive
  3. CThe dielectric surfaces are bonded first, then heating expands the copper so the copper pads press together and join by diffusion
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Answer: C. The dielectric surfaces are bonded first, then heating expands the copper so the copper pads press together and join by diffusion

In hybrid bonding, planarized and activated dielectric (oxide or similar) surfaces are bonded near room temperature, and a subsequent anneal strengthens the dielectric bond. The copper pads are slightly recessed; thermal expansion during heating presses them together into close contact, and atomic diffusion merges them.

  • A. Not using solder is a defining feature of hybrid bonding.
  • B. No adhesive is used.
  • C. Correct. It combines dielectric bonding with copper expansion from heating.
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More Advanced packaging (3D and chiplets) questions

  1. In classifying TSVs by when they are formed, which approach makes TSVs after forming transistors but before forming the multilayer interconnect?
  2. Which pair of typical pitches (terminal spacing) for chip-to-chip connections is most appropriate?
  3. In manufacturing fan-out wafer-level packages, what is the problem called in which chips shift position because of resin flow or shrinkage during curing when they are encapsulated?
  4. What is the main reason for setting a keep-out zone around TSVs where no transistors are placed?
  5. Which correctly describes chiplets?