Interconnect processes

If the spacing between adjacent wires in the same layer is halved, approximately how does the capacitance between them change? (Approximate as parallel plates.)

  1. AIt roughly halves
  2. BIt does not change
  3. CIt roughly doubles
Show answer and explanation

Answer: C. It roughly doubles

The capacitance of parallel plates is C = εS/d, inversely proportional to spacing d. Halving the spacing roughly doubles the capacitance between wires. As scaling narrows spacing, capacitance increases, raising delay, power and crosstalk, so low-k materials and similar measures are used.

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