Experimental and numerical studies of tungsten line growth in laser chemical vapor deposition

Nano to micro tungsten films are widely used as low resistivity electrical connections in MEMS industry. Pyrolytic laser chemical vapor deposition (LCVD) can directly fabricate thin films or microstructures with the minimum thermal damage. The optimal conditions of the tungsten film growth in LCVD are studied by combining experiments and numerical simulations. A proper region of laser powers is determined by the systematical experiments, which is in the range 40–66 W. Based on a transient numerical model, computational chemistry method within the transition state theory is employed to investigate the deposition rate in the multi-line scanning process. It is found that the energy consumption and vacuum requirement of LCVD are the lowest of all tungsten-film fabrication technologies. From the numerical results the average growth rate is controlled by the laser power and the film uniformity mainly depends on the hatch space. The results provide the guidelines of choosing optimal growing conditions and are helpful in producing high quality tungsten films using laser technique.