Interconnect processes

What is the effect of increasing a wire's thickness (height) without changing its width?

  1. ANeither resistance nor capacitance changes
  2. BBoth resistance and capacitance drop
  3. CResistance drops, but the area facing adjacent wires grows, raising inter-wire capacitance
Show answer and explanation

Answer: C. Resistance drops, but the area facing adjacent wires grows, raising inter-wire capacitance

A thicker wire has a larger cross-section, so its resistance drops. But the sidewall area facing adjacent wires increases, raising inter-wire capacitance. Wire thickness (aspect ratio) is therefore chosen by balancing delay, power and crosstalk.

  • A. Both the cross-section and the facing area change, so both quantities change.
  • B. Capacitance rises because the facing area grows.
  • C. Correct. Resistance drops and capacitance rises.
Practice this topic Back to topic

More Interconnect processes questions

  1. In chips using mechanically weak low-k films, what is the problem called in which stress during packaging cracks or delaminates the films?
  2. 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?
  3. In electromigration testing, wires shorter than a certain length show greatly extended lifetimes, with almost no degradation. What is this phenomenon called?
  4. When a wire becomes narrower than its grains so that grain boundaries line up across the wire, what is this structure called, and how does it affect electromigration?
  5. When high-frequency signals flow in a wire, what is the phenomenon called in which current concentrates near the conductor surface and the effective resistance rises?