Fast and Cost-Effective Fabrication of Ultrathin (20 μm) Silicon Substrates by Melt-Spinning

Thin silicon wafer fabrication is a crucial aspect of semiconductor manufacturing, offering enhanced material yield and reduced fabrication costs. Traditional techniques for producing thin silicon substrates often involve the use of supporting substrates for bonding/debonding or intricate processes, such as etching and thinning. In this study, we present the fabrication of an ultrathin polycrystalline silicon substrate utilizing a melt-spinner approach. Our approach has yielded a substrate of unprecedented dimensions, characterized by a width of 1 cm, a length of 5 cm, and an approximate thickness of 20 μm, and fabricated at a speed of 35 m s^-1. This development marks a significant progression in the domain of silicon substrate fabrication, as it stands as the thinnest free-standing polycrystalline silicon substrate achieved to date. Our approach presents substantial potential for cost-effective substrate manufacturing, eliminating the need for the current thinning and etching steps that contribute to material waste, excessive processing time, and high electricity consumption for melting raw silicon material as melt-spun silicon substrates require a postprocessing step of polishing for less than 10 min. This advancement is poised to benefit not only silicon photovoltaic applications but also a broad range of applications, including lightweight wearable electronics, ultrathin membrane structures, microelectromechanical systems for sensing, and the development of advanced material processing.