Product Code: ICA10_M502

Laser Fabrication of Nanobump Arrays on Si Substrate Via Optical Near-Field Enhancement
Authors:
X.C. Wang, Singapore Institute of Manufacturing Technology (SIMTech); Singapore Singapore
Hongyu Zheng, Singapore Institute of Manufacturing Technology; Singapore Singapore
C. W. Tan, Singapore Institute of Manufacturing Technology (SIMTech); Singapore Singapore
F. Wang, Nanyang Technological University; Singapore Singapore
H. Y. Yu, Nanyang Technological University; Singapore Singapore
K. L. Pey, Nanyang Technological University; Singapore Singapore
Presented at ICALEO 2010

Fabrication technologies on the submicrometer and even nanometer scale are receiving more and more attention and are being intensively investigated due to their important industrial applications. Motivated by the problem of structure damage in dry laser cleaning of submicron particles on surfaces, an approach involving the illumination of micro/nanometer sized spheres using a laser beam was recently demonstrated to produce nanoscale pattern on a solid surface, where a micro or nano spherical particles act as lenses and intensify the incoming laser beam. With this approach, most of the works have been on fabrication of nanoscale pits or dents.
In this paper we report on the fabrication of silicon nanobumps on an n-doped (100) Si wafer with silica microspheres. In the process, a single 248 nm excimer laser pulse was applied on a self-assembled monolayer of 1.5-µm-diameter silica microspheres on a n-doped (100) Si wafer. After laser irradiation at a fluence of 300 mJ/cm2, a regular array of conical Si nanobumps surrounded by a ring shaped trench were fabricated. The structure of the nanobump arrays was characterized by scanning electron microscope, and atomic force microscope. The formed nanobumps were determined to be Si-based bumps with energy disperse spectroscopy. The mechanisms involved in the formation of nanobumps were discussed. The developed Si nanobump pattern has potential applications for sensitive detectors, efficient photovoltaic cells, field-emitter arrays, and displays.