- The semiconductor industry is transitioning from tungsten to molybdenum (Mo) to meet the demands of the AI era
- Molybdenum’s lower resistivity and lack of barrier layer enable scalability while simplifying the manufacturing process
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For nearly a quarter of a century, the semiconductor industry has relied on tungsten as the interconnect material of choice for advanced memory and logic applications.
But as traditional metallization approaches reach their physical limits to meet evolving scaling demands for the AI era, the industry is turning to a new material–molybdenum.
What is an interconnect anyway? Interconnects are the intricate wiring networks that connect components on a chip.
- They function like a plumbing system, transporting electrons and connecting transistors and other components.
- Just as a blockage in a plumbing system can disrupt the water flow, a chip’s performance depends on the smooth movement of signals and power through these wires. Inefficiencies in interconnects can bottleneck a chip’s performance, slowing its speed and reducing efficiency.
The backstory: The industry has addressed interconnect scaling using three main materials. Aluminum interconnects transitioned to copper and tungsten depending on the interconnect type.
The challenge: As AI drives the demand for greater computing power, chipmakers are stacking components in dense 3D architectures to pack in more performance. The “pipes” (or interconnects) must be made thinner and more efficient to carry more “water” (or electrical signals) through tighter spaces without losing “pressure” (or signal strength). As the industry races to scale to meet increasing demands from AI, tungsten is being pushed to its limits.
Enter molybdenum: Molybdenum is emerging as a promising alternative to tungsten.
- Molybdenum has lower resistivity compared to tungsten in small features, which allows electrical currents to flow more easily, like how smoother pipes allow water to flow more freely.
- It also doesn't need an adhesion or barrier layer like tungsten. In plumbing, you might need an extra layer to prevent leaks and ensure the pipes stay in place, which can add additional complexity and cost.
- Finally, its shorter mean-free path—the distance electrons can travel before colliding—makes it more suitable for advanced, smaller device structures, allowing electrons to travel more efficiently.
Botton line: The transition to molybdenum marks a new metallization inflection point, allowing chipmakers to build devices for the AI era and beyond.
Read about Lam’s ALTUS® Halo, the world’s first atomic layer deposition (ALD) tool that harnesses the capabilities of the metal molybdenum in the production of leading-edge semiconductors.
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