Interconnect processes

What is the basic role of the interlayer dielectric that fills the space between wires?

  1. ATo lower wire resistance
  2. BTo set the transistor threshold voltage
  3. CTo electrically insulate wires from each other and prevent shorts
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Answer: C. To electrically insulate wires from each other and prevent shorts

The interlayer dielectric electrically insulates adjacent wires in the same layer and wires in upper and lower layers, preventing shorts. Because it also affects capacitance between wires, low-permittivity (low-k) materials have come into use.

  • A. The insulator does not lower wire resistance.
  • B. The threshold voltage is set by the transistor's gate structure and similar.
  • C. Correct. It insulates wires from each other.
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More Interconnect processes questions

  1. Why has an Al-Cu alloy with about 0.5% copper been used for aluminum wiring?
  2. What is the phenomenon called in which electroplated Cu films, simply left at room temperature, grow larger grains over time and drop in resistivity?
  3. What is the main purpose of the design practice of placing two or more vias, rather than one, wherever possible to connect upper and lower wires?
  4. Which term refers to the contacts and local interconnects that connect the transistors to the multilevel wiring?
  5. In scaled multilevel wiring, what is the main reason via resistance has become a problem?