Multi-scale simulation of ALD of dielectrics and metals with IProS 2D software

IPros 2D can be used for coupled multi-scale simulation and optimization of ALD in single wafer and batch reactors:

  • shortening the process cycle
  • improving on-wafer and wafer-to-wafer uniformity
  • improving within-trench conformality

Key output characteristics include step coverage and mass gain.

Reactor-scale simulations include unsteady mass transport and heat transfer. At each time step, feature-scale simulations take the results for reactant delivery from reactor-scale mass transport models and, after computations inside the trench, provide feedback reflecting the reactant consumption etc. to the reactor-scale model. 

Model of the species transport and chemical interaction inside the trench enables detailed simulation of sidewall coverage evolution.

Software supports simulation of heating elements and optimization of thermal profile in the reactor chamber.

 

Example: Coupled reactor and feature scale modeling of ALD of HfO2 on a patterned wafer

Multi-scale model of HfO2 ALD in a vertical batch reactor with 66 12” patterned wafers (doi:10.1016/j.surfcoat.2007.04.079).  

Cylindrical trenches with AR 60: D = 200 nm, h = 12 μm. Trench tops take about 5% of the blanket wafer area.

The difference between the coverage of the mesa top vs coverage deep inside the trench. Both characteristics are plotted along the wafer (center to periphery, as marked in the figure above by green and grey dots respectively) at 20 seconds into the Hf step.  

Left: Evolution of precursor distribution in the batch reactor. 

Example: ALD of TiN on a patterned wafer

This case includes flow modeling with showerhead and species transport coupled with deposition on patterned wafer – trenches with AR 100.

Shown results, starting from the top:

  • Flow pattern and TiCl4 distribution in the reactor 
  • Evolution of trench sidewall coverage in trenches with AR 100. 
  • Comparison of mass gain for two different pulse durations. Note, that effective mass gain per wafer area includes so-called loading effect, mass accumulation inside the trenches.