Papers by Keyword: Anisotropic Wet Etching

Abstract: The experimental trials were conducted by design of experiments (DOE) technique to find an anisotropic wet etching condition that achieves 90° wall angle on silicon (100) orientation wafer. Three considered factors assigned to the DOE were NaOH concentration, solution temperature, and stirring speed. The response aimed for this study was not only targeting at 90° wall but also providing highest etch rate. The experimental results showed that in order to fabricate the 90° wall angle, the best etching condition using was 30% wt NaOH concentration, 80°C solution temperature, and 300 rpm stirring speed. This condition gave an etch rate of 1245 nm/min with surface roughness (R_a) of 701.48 nm.

Abstract: The experiments to study the feasibility to fabricate the 45 slant on p-type (100)-oriented silicon wafer were done. The various mask shapes, rectangular, cross, circle and boomerang, were patterned on the SiO2 mask by utilizing the conventional photolithography and dry etching process for investigating the anisotropic wet etch characteristic. The edge of masks were align in two crystal direction, 110 and 100 that is allowable to get a better understanding about the crystal orientation and the angle between planes in a crystal system. The very low etch rate,  50 nm/min, process regime was selected to fabricate the 45 slant with the concept is the lowest of an overall etch rate in the system to reach the level that is possible to detect the (110) plane. The etch recipe can be used for the next development work to built a housing of the laser light source for applying in a data storage technology.

Abstract: The advantages of micromachining over conventional fabrication include precise dimensional control, integration of on-chip circuits and potential low cost owning to batch processing. Fabrication microspeaker for hearing instrument application using MEMS technology is challenging because of certain critical requirements, including their small size, low driving voltage, high output sound pressure level, flat frequency response and low energy consumption. A small in size, lightweight, and low cost microspeaker is demanded for application such as cellular phones and hearing aids. The device consist of two part; first parts is a micromachined polyimide membrane as the sound generating plate, where thevoice coil placed on the top of membrane, and the coil is a single loop voice coil. The second part is back plate permanent magnet. The disc permanent magnet bonded on acoustic hole plate is Neodymium-Iron-Boron (NdFeB) with magnetization of 1.45 T, diameter 1.6 mm, and thickness 0.8 mm. The fabrication process and performance of the first result device is discussed, and the thickness of electroplated single loop voice coil copper 10 mm and acoustic hole bonded together. The total size of the microspeaker chip is 5 mm x 5 mm x 1.5 mm, polyimide membrane thickness 2 mm.