Interconnect processes

In scaled multilevel wiring, what is the main reason via resistance has become a problem?

  1. AThe via cross-section shrinks, and the high-resistance barrier metal takes up a larger share of it
  2. BVias have become longer
  3. CCurrent no longer flows through vias
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Answer: A. The via cross-section shrinks, and the high-resistance barrier metal takes up a larger share of it

As vias narrow, their cross-sectional area shrinks and resistance rises, and the high-resistance barrier metal that prevents Cu diffusion cannot be thinned much, so it occupies a growing share of the via. Thinner barriers and alternative materials are therefore being explored.

  • A. Correct. A shrinking cross-section and a growing barrier share are the causes.
  • B. Scaling does not make vias longer.
  • C. Current does flow through vias.
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More Interconnect processes questions

  1. Which statement about the capacitance of a wire is correct?
  2. What is the effect of increasing a wire's thickness (height) without changing its width?
  3. In chips using mechanically weak low-k films, what is the problem called in which stress during packaging cracks or delaminates the films?
  4. What film is commonly placed on top of Cu wiring to act both as a diffusion barrier toward the dielectric and as an etch stop?
  5. In electromigration testing, wires shorter than a certain length show greatly extended lifetimes, with almost no degradation. What is this phenomenon called?