Thermal Spray Equipment and Materials Considerations for Electronics and Semiconductor Equipment Coatings

Silicon coatings produced using a thermal plasma spray process can have an economical advantage in the semiconductor equipment industry due to the speed in which the material is deposited.  In order to obtain high quality coatings for the semiconductor, target, and electrical industries, atmospheric thermal plasma spraying of silicon must be well understood.  Examples for thermally sprayed silicon coatings range from uses in electronics to the semiconductor equipment industry.  In order to produce the high quality coatings required in these industries, it is desirable to control the final properties of the silicon coating.  Efforts conducted on thermal spraying of silicon include investigations into the microstructure, due to the coating quality importance in electrical transport properties.  In addition, direct measurements of the electrical resistivity have been undertaken to show the importance of the spray parameters on the resulting depositions.

 An investigation into the microstructure and chemical composition of silicon depositions after being subjected to directional re-solidification.  Zone melt recrystalization (ZMR) of the depositions resulted in crystalline grain sizes up to 100µm.  There was also evidence that the melt resulted in a slag at the surface, which could be chemically etched away.  Understanding and controlling the silicon grain growth, microstructure densification and impurity concentration may have important implications in producing coatings in the electronics to semiconductor equipment industries.