• Journal of the Microelectronics and Packaging Society
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• v.29 no.4
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• pp.1-8
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• 2022

High-density packaging technologies, including Through-Si-Via (TSV) technologies, are considered important in many fields such as IoT (internet of things), 6G/5G (generation) communication, and high-performance computing (HPC). Achieving high integration in two dimensional packaging has confronted with physical limitations, and hence various studies have been performed for the three-dimensional (3D) packaging technologies. In this review, we described about the causes and effects of scallop formation in TSV, the scallop-free etching technique for creating smooth sidewalls, Cu pillar and Cu-SiO₂ hybrid bonding in TSV. These technologies are expected to have effects on the formation of high-quality TSVs and the development of 3D packaging technologies.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.467-468
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• 2006

• Journal of the Korean Society for Precision Engineering
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• v.16 no.4 s.97
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• pp.129-137
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• 1999

A parametric curve interpolator has been proposed for machining curves instead of a linear interpolator in which curves are approximated by a set of line segment. The parametric curve interpolator is superior to linear interpolator in machining time and contour error and generate exact position commands directly from curve equations. In this paper, a new toolpath generation method is proposed based on the parametric curve interpolator. This method retains all the benefits of parametric curve interpolator and can bound the scallop height within a specified value. By interpolating curves and surfaces directly from the mathematical equations, the amount of data from CAD/CAM system to CNC controller can be significantly reduced. The proposed method was implemented on a CNC controller and was confirmed to give a better result than the other existing method.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.1
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• pp.23-30
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• 2021

To examine the optimal temperature, light intensity, and shell-type for shell-living conchocelis production, we tested the shell infiltration of free-living conchocelis fragments under various environmental conditions. Under a combination of various temperatures (10, 15, 20, 25 and 30℃) and light intensities (1, 5, 10, 20, 40, and 80 μmol m-2 s-1), the optimal infiltration conditions of the evaluated three Pyropia species were 20-25℃ and 5-80 μmol m-2 s-1 for P. yezoensis, 20-30℃ and 20-80 μmol m-2 s-1 for P. seriata, and 20-25℃ and 20-80 μmol m-2 s-1 for P. dentata. The infiltration efficiency of free-living conchocelis for different shell types was greater in Korean and Chinese oyster Crassostrea gigas shells than that in scallop Argopecten irradians and clam Meretrix lusoria shells. These results suggest that oyster shells are suitable substrates for shell-living conchocelis production. In conclusion, the present results for optimal infiltration conditions for free-living conchocelis of the three examined Pyropia species will contribute significantly to the production of stable shell-living conchocelis.

• Proceedings of the KWS Conference
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• 2006.05a
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• pp.30-32
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• 2006

The interfacial reaction and reliability of eutectic Sn-Pb and Pb-free eutectic Sn-Ag ball-grid-array (BGA) solders with an immersion Ag-plated Cu substrate were evaluated following isothermal aging at $150^{\circ}C$. During reflowing, the topmost Ag layer was dissolved completely into the molten solder, leaving the Cu layer exposed to the molten solder for both solder systems. A typical scallop-type Cu-Sn intermetallic compound (IMC) layer was formed at both of the solder/Cu interfaces during reflowing. The thickness of the Cu-Sn IMCs for both solders was found to increase linearly with the square root of isothermal aging time. The growth of the $Cu_3Sn$ layer for the Sn-37Pb solder was faster than that for the Sn-3.5Ag solder, In the case of the Sn-37Pb solder, the formation of the Pb-rich layer on the Cu-Sn IMC layer retarded the growth of the $Cu_6Sn_5$ IMC layer, and thereby increased the growth rate of the $Cu_3Sn$ IMC layer. In the ball shear test conducted on the Sn-37Pb/Ag-plated Cu joint after aging for 500h, fracturing occurred at the solder/$Cu_6Sn_5$ interface. The shear failure was significantly related to the interfacial adhesion strength between the Pb-rich and $Cu_6Sn_5$ IMC layers. On the other hand, all fracturing occurred in the bulk solder for the Sn-3.5Ag/Ag-plated Cu joint, which confirmed its desirable joint reliability.

• Journal of Aquaculture
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• v.6 no.1
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• pp.1-12
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• 1993

Identification of blood cells and their physological functions in the cultured scallop, Patinopecten yessoensis collected from Abashiri Bay, Hokkaido, Japan were studied by electron microscopic structure and histological observations. The physiological function of each blood cell type was studied on the basis of its cytological structure, the lysosome in the blood cell and its phagocytosis. The blood cells were classified as Type I, Type II and Type III. The morphological characteristics of each blood cell type are as follows ; Type I : The cell is oval shaped and its cytoplasm contains comparatively low electron dense materials. The oval nucleus is sometimes ramified into two nuclei. Lumps of tubular smooth endoplasmic reticula and vacuoles are distributed near the nucleus. Type II : The cell appears long and oval shaped, and its cytoplasm contains high electron dense materials. The oval nucleus does not ramify, and large numbers of sac-like smooth endoplasmic reticula and free ribosomes are developed around the nucleus. No vacuoles exist in the cytoplasm Type 1II : The cell is round in shape and the electron density of the cytoplasm is the highest among the three types of cells because of large quantities of rough­surfaced endoplasmic reticula and no vacuoles. Particularly, the nucleus reveals a wheel-like shape owing to lumps of tuberous chromatin. The cells of Type I and II seem to have the role of carrying out phagocytosis on either foreign materials such as bacteria or endogenous old cells and the transport of nutritive materials. The type III cell, which has not been found in any bivalve species of non Pectinidae, may be said to have the function of production and the secretion of protein related to some humoral defense materials.

• Korean Journal of Materials Research
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• v.12 no.9
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• pp.750-760
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• 2002

In this study, three solders, Sn-37Pb, Sn-3.5Ag, and Sn-3.8Ag-0.7Cu were screen printed on both electroless Ni/Au and OSP metal finished micro-via PCBs (Printed Circuit Boards). The interfacial reaction between PCB metal pad finish materials and solder materials, and its effects on the solder bump joint mechanical reliability were investigated. The lead free solders formed a large amount of intermetallic compounds (IMC) than Sn-37Pb on both electroless Ni/Au and OSP (Organic Solderabilty Preservatives) finished PCBs during solder reflows because of the higher Sn content and higher reflow temperature. For OSP finish, scallop-like $Cu_{6}$ /$Sn_{5}$ and planar $Cu_3$Sn intermetallic compounds (IMC) were formed, and fracture occurred 100% within the solder regardless of reflow numbers and solder materials. Bump shear strength of lead free solders showed higher value than that of Sn-37Pb solder, because lead free solders are usually harder than eutectic Sn-37Pb solder. For Ni/Au finish, polygonal shaped $Ni_3$$Sn_4$ IMC and P-rich Ni layer were formed, and a brittle fracture at the Ni-Sn IMC layer or the interface between Ni-Sn intermetallic and P-rich Ni layer was observed after several reflows. Therefore, bump shear strength values of the Ni/Au finish are relatively lower than those of OSP finish. Especially, spalled IMCs at Sn-3.5Ag interface was observed after several reflow times. And, for the Sn-3.8Ag-0.7Cu solder case, the ternary Sn-Ni-Cu IMCs were observed. As a result, it was found that OSP finished PCB was a better choice for solders on PCB in terms of flip chip mechanical reliability.

• Food Science and Preservation
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• v.18 no.4
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• pp.535-545
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• 2011

The nutrient composition, including the proximate composition and the mineral, vitamin, amino acid, and free-amino-acid levels, of baechu kimchi (Chinese cabbage kimchi) to which 14 kinds of seafood (flatfish, yellow corvina, sea beam, pollack gizzard shad, ray, gray mullet, skate, hairtail, anchovy, sea squit, pen shell, scallop, small octopus)were added was analyzed. The seafoods were added to salted cabbage at concentration of 10% (w/w) and the prepared seafood baechu Kimchi (BK) was stored at $5^{\circ}C$ for seven days. The levels of moisture (82.09-88.56%), crude lipid (0.31-0.64%), and crude ash (2.70-3.50%) did not differ much among the samples, but the level of crude protein of the BK-with-seafood samples (2.42-5.15%) was greater than that of the control BK (2%), without seafood. The Fe and Ca contents of BK with flatfish showed the highest values (4.1 and 74 mg/100 g, respectively). The vitamin A contents of BK samples with 14 different kinds of seafood were higher than that of the control BK. Moreover, the BK with sea squit had higher vitamin $B_2$ (0.90 mg/100 g) and vitamin C (8.48 mg/100 g) contents among all the BK-with-different-kinds-of-seafood samples. Total amino acids were detected in all BK-with-seafood samples, most of which had high levels of glutamic acid, aspartic acid, proline and alanine. Glutamic acid was the most abundant of all the amino acids. The major free amino acids were hydroxyproline, glutamic acid, alanine, proline, leucine, and valine, of which hydroxyproline was the most abundant. In conclusion, BK with seafood is thought to be a very good source of protein, which is very important from dietary life of humans.