Papers by Author: Dong Iel Kim

Abstract: Adhesion strength for single layer ceramic capacitor sheet, used in MLCC(Multilayer Ceramic Capacitor), was measured by peel tests. The peel strength was measured during the separation of the ceramic sheet from the PET film using the peel testing system developed in this study. The sheet specimen was adhered on the glass jig floating on the liquid media, which was designed to minimize the friction, and the specimen was pulled up by micro-actuator. In this study, the dependency of the specimen width, peel angle and testing speed on the adhesive strength was experimentally investigated. It was found that the adhesive strength for the ceramic sheet is nearly identical, irrespective of the specimen width ranged from 5 to 20 mm, and the adhesive strength was increased with increasing testing speed. Furthermore, the strength was shown to be dependent on the peel angle.

Abstract: To measure the micro-mechanical properties for micro/nano materials, out-of-plane ESPI system and micro-strip bend testing system were developed. For the bending system, PZT actuator was controlled with the stroke resolution of 0.6 nm and out-of-plane ESPI system was developed in compact and portable type. To quantitatively analyze the out-of-plane ESPI fringe patterns, 4-bucket technique was used and unwrapped phase map was obtained. Electrolytic copper foil with the thickness of 18 μm was used for preparation of the strip bend specimen with length of 8 mm and three different widths of 2, 3 and 5 mm. The strip bending tests showed that the out-of-plane deflection in the bend specimen was measured with a maximum of 8 % in error. Furthermore, from the experiment, the variation of the deflection along the supporting span could be determined and significant region was linear.

Abstract: To determine the micro-mechanical properties for micro/nano materials, it may be essential to measure the strain/deformation during micro-mechanical testing. Therefore, in this study, continuous measurement of in-plane tensile strain in micro-sized specimens of thin film materials was introduced using the micro-ESPI technique. TiN and Au thin films 1 and 0.47µm thick, respectively, were deposited on the silicon wafer and fabricated into the micro-sized tensile specimens by the electromachining process. The micro-tensile loading system and micro-ESPI system were developed to measure the tensile strain during micro-tensile loading. Micro-tensile stress-strain curves for these materials were determined using the algorithm for continuous strain measurement. Furthermore, the new algorithm for enhancing the sensitivity to measurement of in-plane tensile strain was suggested. Using the algorithm, micro-tensile strain data between interfringes were calculated. It is shown that the algorithm for enhancement of the sensitivity suggested in this study makes the sensitivity to the in-plane tensile strain increase.