Interconnect processes

In multilevel interconnects, what is the main reason upper-level wires are made wider and thicker?

  1. ABecause the upper levels must transmit light
  2. BBecause fine patterning is harder in upper levels
  3. CTo reduce the resistance of long power and signal wires
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Answer: C. To reduce the resistance of long power and signal wires

Lower-level wires connect nearby transistors densely and are thin, while upper-level wires distribute power across the chip and connect distant blocks, so they are made wide and thick. Lowering the resistance of long wires limits voltage drop and signal delay.

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More Interconnect processes questions

  1. What is the main purpose of the technique that makes part of the insulator between wires a cavity (air gap)?
  2. Which correctly describes backside power delivery, which is being introduced in advanced logic?
  3. What is the phenomenon called in which current flowing through the resistance of power wiring lowers the supply voltage that reaches circuits?
  4. What is the phenomenon called in which, through capacitive coupling between adjacent wires, a signal change on one wire appears as noise on the other?
  5. What is the main purpose of placing a cap layer such as cobalt on top of copper wiring?