Lam’s market-leading ALTUS® systems combine CVD and ALD technologies to deposit the highly conformal films needed for advanced metallization applications.
Molybdenum (Mo) can be deposited using ALD to provide better filling of device features. Alternatively, it can be deposited with non-fluorinated halide precursors to avoid dielectric damage caused in some tungsten applications. The etchback and chemical-mechanical planarization (CMP) processes are accomplished with known chemistries and tool sets for faster integration in the fab process flow.
Tungsten deposition is used to form conductive features like contacts, vias, and plugs on a chip. These features are small, often narrow, and use only a small amount of metal, so minimizing resistance and achieving complete fill can be difficult. At these nanoscale dimensions, even slight imperfections can impact device performance or cause a chip to fail.
As semiconductor manufacturers move to smaller technology nodes, contact metallization processes face significant scaling and integration challenges, such as minimizing contact resistance to meet the lower power consumption and high-speed requirements of advanced devices.
For nanoscale structures, complete fill with tungsten (W) using conventional CVD is limited by overhang from conventional barrier films and deposition techniques. This results in closure of the feature opening before complete fill can take place, leading to voids, higher resistance, and contact failure. Even completely filled smaller features contain less tungsten, which results in higher contact resistance.
Advanced memory and logic features require deposition techniques that enable complete, defect-free tungsten fill, while reducing resistance of the bulk tungsten. Good barrier step coverage and lower resistance at reduced thicknesses (relative to physical vapor deposition/CVD barrier films) is needed to improve contact fill and reduce contact resistance.
The demand for more advanced computational capabilities is increasing considerably and today’s chipmakers are pushing the boundaries of what’s possible in the race to scale.
To meet the requirements of NAND, DRAM, and logic features, different deposition technology is required. Traditional metallization schemes simply cannot meet these scaling requirements, so the industry is implementing molybdenum (Mo) metallization across all three leading edge IC types.
However, significant innovation is needed to make Mo viable in manufacturing using ALD tools. These challenges include: ability to apply high temperatures, enabling advanced reactor and process sequence designs, being able to precisely control wafer temperature and offering bulk delivery of the Mo solid precursor through various chemical handling.
Visit Metallization Solutions page for more information