Interconnect processes

What is the main purpose of using low-k (low dielectric constant) materials for interlayer dielectrics?

  1. ATo reduce wire resistance
  2. BTo increase the mechanical strength of the interlayer dielectric
  3. CTo reduce parasitic capacitance between wires and lower RC delay
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Answer: C. To reduce parasitic capacitance between wires and lower RC delay

As wire spacing narrows, capacitance between wires increases, raising signal delay (RC delay) and power consumption. Insulators with lower permittivity reduce this capacitance. However, low-k materials, which are often porous, tend to have low mechanical strength, which is a challenge in CMP and packaging.

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More Interconnect processes questions

  1. What is the main purpose of barrier metals such as Ta and TaN in copper wiring?
  2. Which correctly describes a via in multilevel interconnects?
  3. If a wire's length is doubled without changing its cross-section or spacing, approximately how many times larger does its RC delay become?
  4. What is the purpose of forming silicides such as NiSi on the surfaces of a transistor's source, drain and gate?
  5. Which metal has been widely used to fill contact holes connecting transistors to the lowest wiring layer?