Interconnect processes

Which metal has been widely used to fill contact holes connecting transistors to the lowest wiring layer?

  1. ATungsten (W)
  2. BGold (Au)
  3. CLead (Pb)
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Answer: A. Tungsten (W)

Contact holes have widely been filled with tungsten, which CVD can deposit deep into narrow holes (tungsten plugs). It is used with Ti or TiN barrier layers to prevent diffusion into silicon.

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More Interconnect processes questions

  1. When copper wires become very narrow, what is the main reason their effective resistivity rises?
  2. In multilevel interconnects, what is the main reason upper-level wires are made wider and thicker?
  3. What is the main purpose of the technique that makes part of the insulator between wires a cavity (air gap)?
  4. Which correctly describes backside power delivery, which is being introduced in advanced logic?
  5. What is the phenomenon called in which current flowing through the resistance of power wiring lowers the supply voltage that reaches circuits?