• Journal of the Korean Society for Precision Engineering
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• v.31 no.12
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• pp.1101-1106
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• 2014

Hybrid manufacturing technology has been advanced to overcome limitations due to traditional fabrication methods. To fabricate a micro/nano-scale structure, various manufacturing technologies such as lithography and etching were attempted. Since these manufacturing processes are limited by their materials, temperature and features, it is necessary to develop a new three-dimensional (3D) printing method. A novel nano-scale 3D printing system was developed consisting of the Nano-Particle Deposition System (NPDS) and the Focused Ion Beam (FIB) to overcome these limitations. By repeating deposition and machining processes, it was possible to fabricate micro/nano-scale 3D structures with various metals and ceramics. Since each process works in different chambers, a transfer process is required. In this research, nanoscale 3D printing system was briefly explained and an alignment algorithm for nano-scale 3D printing system was developed. Implementing the algorithm leads to an accepted error margin of 0.5% by compensating error in rotational, horizontal, and vertical axes.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.5
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• pp.550-555
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• 2007

The effective fracture toughness testing of materials intended for application in Micro Electro Mechanical Systems (MEMS) devices is required in order to improve understanding of how micro sized material used in device may be expected to perform upon the micro scale. ${\gamma}$-TiAl based materials are being considered for application in MEMS devices at elevated temperatures. Especially, in Alloy 4, both ${\alpha}_2$ and ${\gamma}$ lamellae were altered markedly in 3,000 h, $700^{\circ}C$ exposure. Parallel decomposition of coarse ${\alpha}_2$ into bunches of very fine (${\alpha}_2+{\gamma}$) lamellae. Parallel decomposition of coarse ${\alpha}_2$ into bunches of very fine (${\alpha}_2+{\gamma}$) lamellae. The materials were examined 2 types Alloy 4 on heat exposed specimen($700^{\circ}C$, 3,000 h) and no heat exposed one. Micro sized cantilever beams were prepared mechanical polishing on both side at $25{\sim}30{\mu}m$ and electro final stage polishing to observe lamellar orientation of same colony with EBSD (Electron Backscatter Diffraction Pattern). Through lamellar orientation as inter-lamellae or trans-lamellae, Cantilever beam was fabricated with Focused Ion Beam(FIB). The directional behavior of the lamellar structure was important property in single material, because of the effects of the different processing method and variations in properties according to lamellar orientation. In MEMS application, it is first necessary to have a reliable understanding of the manufacturing methods to be used to produce micro structure.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.3
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• pp.43-50
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• 2014

By the trends of electronic package to be smaller, thinner and more integrative, the reliability of interconnection between Si chip and printed circuit board is required. This paper reports on a study of high speed shear energy of Sn-4.0wt%Ag-0.5wt%Cu (SAC405) solder joints with different the thicknesses of electroless Ni-P deposit. A high speed shear testing of solder joints was conducted to find a relationship between the thickness of Ni-P deposit and the brittle fracture in electroless Ni-P deposit/SAC405 solder. A focused ion beam (FIB) was used to polish the cross sections to reveal details of the microstructure of the fractured pad surface with and without $HNO_3$ vapor treatment. The high speed shear energy of SAC405 solder joint with $1{\mu}m$ Ni-P deposit was found to be lower without $HNO_3$ vapor, compared to those of over $3{\mu}m$ Ni-P deposit. This could be due to the edge of solder resist in $1{\mu}m$ Ni-P deposit, which provides a fracture location for the weakened shear energy of solder joints and brittle fracture in high speed shear test. With $HNO_3$ vapor, the brittle fracture mode in high speed shear test decreased with increasing the thickness of Ni-P deposit. Then the roughness (Ra) of Ni-P deposits decreased with increasing its thickness. Thus, this gives the evidence that the decrease in roughness of Ni-P deposit for Eelectroless Ni/ Electroless Pd/ Immersion Au (ENEPIG) surface play a critical role for improving the robustness of SAC405 solder joint.