Reduction of geometric error in FIB fabrication of micro structures = 집속이온빔을 이용한 미세구조물의 형상정밀도 향상

다국어 초록 (Multilingual Abstract)

Micro-nano structure processing using FIB (Focused Ion Beam) is especially attracting recent interests since sputtering and deposition processes can be applied to various materials and 3D structure processing can be easily implemented. However, like other beam-based manufacturing processes, the redeposition of the sputtered material during the machining deteriorates the geometric accuracy of ion beam machining. In this research a new approach to reduce the geometric error in FIB machining is introduced. The observed redeposition phenomena have been compared with existing theoretical model. Although the redeposition effect has good repeatability the prediction of exact amount of geometric error in ion beam machining is difficult.Therefore, proposed method utilizes process control approach. Developed algorithm measures the redeposition amount after every production cycle and modifies next process plan. And measurement of information of the amount and the shape about geometric error using a image processing method. The geometric error compensation method has been implemented to a real FIB machine and the experimental results demonstrated considerable improvement of micrometer-sized pocket, circular cone and steps structures machining.We find out the optimized FIB milling conditions such as beam current, overlap and dwell time will be applied in the experiment for the geometric error compensation method using preliminary experiment. Therefore, the robust design methodology is to optimize the product quality such ad the surface roughness, geometry accuracy and fabricated depth. Another aspect we can predict machining surface by overlap in FIB fabrication.Accordingly, the development provides ingredients for fundamental research activities in the 3D design technology of the final product with enhanced geometric accuracy by enabling all aspects of processing, including basic processing, measurement and modified processing, within single FIB equipment.