抄録
Particulate contamination on a wafer is the most crucial problem for wafer bonding, which is one of key process technologies for MEMS (Micro Electro Mechanical Systems). To address the problem, physical assists such as megasonic agitation is generally employed, but acoustic agitation often causes damage to fragile MEMS structures. In this study, several cleaning methods were compared in terms of both particle removal efficiency (PRE) and damage to the fragile MEMS structures. Conventional immersion type cleaning or ultrasonic cleaning cannot remove small particles efficiently, while atomized water jet spray (2-fluid jet spray) cleaning with pressurized nitrogen gas can effectively remove particles without damage to cantilever structures in a short time. Megasonic cleaning with de-ionized water can remove the particles, but it damages the cantilever structures at a same time. In contrast, megasonic cleaning with surfactant dissolved water or diluted ammonia/H2O2 water can effectively remove particles even at a low physical energy, which causes no damage to the structures.
