Laser Welding for Processing of Thin Crystalline Si Wafers

Thin crystalline Si films (<100 μm) are used in many applications, such as sensors, photovoltaic absorbers, and optical and particle filters. Such thin crystalline Si films are difficult to handle and break easily under standard semiconductor processing. This paper presents a laser-welding process for the mechanical connection of a thin Si film with a separate stabilizing frame that is also made of crystalline Si. We measure the tear-off stresses to be in the range of 17-50 kPa. The supported thin Si films withstand typical semiconductor processes such as plasma deposition, oxidation, and wet chemical cleaning.