Optimization of inlets and outlets of an ALD chamber with radiant heating

A chemical reaction chamber was designed and manufactured to grow high quality, ultra-thin films using the atomic layer deposition (ALD) technology. As the distribution of temperature and gas pressure has large influences on the thickness of sub-nanometer films, it is crucial to achieve uniformity in terms of temperature and gas flow on the substrate. We report here the design and optimization of a cross-flow structured and radiation heated chamber, with special focus on the multi-inlet and multi-outlet structures to deliver the precursors and to get better distribution uniformity. Simulations based on finite element method (FEM) are employed to optimize the structure and corresponding experiments are made to validate with the simulation results.We find that by adjusting the inlet and outlet parameters, such as the inlet numbers and diameter, it is possible to achieve better uniformity of pressure on the substrate and a narrower film thickness distribution within the chamber. Factors influencing the gas flow over the wafer surface are reported and discussed.