• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.120.2-120.2
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• 2017

본 연구에서는 고신뢰성 인쇄회로기판이나 플립칩 패키지에 적용되는 범프 표면처리에서 널리 사용되는, ENIG나 ENEPIG 대체를 위한 electroless Pd/immersion Au(EPIG)에 대하여 연구하였다. Transmission electron microscopy(TEM) 분석 결과 형성된 Au layer는 crystalline, Pd layer는 amorphous 임을 확인하였으며, 열처리 후 X-Ray photoelectron spectroscopy(XPS)를 통하여 EPIG층이 하부 copper의 확산방지막으로서 효과가 있음을 알 수 있었다. 또한, 비정질 Pd layer가 확산을 방지하기 위하여는 일정수준 이상의 두께가 필요하며, 그 두께는 35~65nm 수준임을 알 수 있었다.

• Journal of the Korean institute of surface engineering
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• v.50 no.3
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• pp.170-176
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• 2017

EPIG (Electroless Pd/immersion Au) process was studied to replace ENIG (electroless Ni/immersion Au) and ENEPIG (electroless Ni/electroless Pd/immersion Au) processes for bump surface treatment used in high reliable flip chip packages. The palladium and gold layers formed by EPIG process were uniform with thickness of 125 nm and 34.5 nm, respectively. EPAG (Electroless Pd/autocatalytic Au) also produced even layers of palladium and gold with the thickness of 115 nm and 100 nm. TEM results exhibited that the gold layer in EPIG surface had crystalline structure while the palladium layer was amorphous one. After annealing at 250 nm, XPS analysis indicated that the palladium layer with thickness more than 22~33 nm could act as a diffusion barrier of copper interconnects. As a result of comparing the chip shear strength obtained from ENIG and EPIG surfaces, it was confirmed that the bonding strength was similar each other as 12.337 kg and 12.330 kg, respectively.

• Journal of Animal Science and Technology
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• v.44 no.2
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• pp.207-212
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• 2002

This study was conducted to investigate the genotypes and frequencies of Melanocortin 1 Receptor(MC1R) genes in pigs which plays a central role in regulation of eumelanin (black/brown) and phaeomelanin(red/yellow) pigment synthesis within the mammalian melanocytes. Four different breeds of pigs(20 Landrace, 20 Yorkshire, 20 Duroc, and 93 Jeju native black pigs) were used and PCR-RFLP analysis of MC1R gene was also carried out. Two regions of MC1R genes (428bp and 405bp) were amplified using two specific primers (MERL1-EPIG2, EPIG1-EPIG3), respectively and MC1R allele were determined using 2 restriction enzymes (BspHⅠ, AccⅡ). The results of this experiment indicated that MC1R allelic type in Landrace, Large Yorkshire and Duroc were MC1R *2 (Ep), MC1R *2 (Ep), MC1R *4 (e), respectively. However, various allelic types of MC1R genes were detected in Jeju native black pigs. MC1R allelic type of Jeju black pigs was MC1R*2 type as in Meishan and Large black breeds or MC1R*3 type as in Hampshire and Berkshire breeds and the gene frequencies of ED1 and ED2 were 0.554 and 0.446 in average.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.1
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• pp.49-54
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• 2023

Recently, System in Packaging(SIP) technology needs to meet high frequency (5G and more) communication technology and fine pitch surface treatment. The conventional Electroless Ni/Immersion Au plating(ENIG) is not suitable for high frequency range because of magnetic properties are increasing the transmission loss. Without nickel plating layer, the pattern and pad reliability level must be meet the condition. In this review paper, we investigated research trends on Ni-less surface treatment technology for high-frequency communication and frequency characteristics according to materials.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.3
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• pp.356-362
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• 2003

The present study was conducted to know the physicochemical properties of non fermented tea and fermented teas with the fermented time of 0 hr (non fermented tea), 10 hrs, 17 hrs (semi-fermented tea), 24 hrs (black tea), respectively The moisture content of non fermented tea, semi fermented, and black tea was 3.01% ~ 3.29%. The contents of reducing sugar, crude lipid, crude protein were increased and that of ascorbic acid was decresed with fermentation. The total contents of those increased as tea was more fermented. The contents of the citric acid and the malic acid were increased with fermentation, but the content of the succinic acid was decreased. However, the total content of organic acid was generally increased with fermentation. The total content of the amino acid was increased with fermentation. In non fermented tea, Thr+theanine, the Asp, and the Glu, were determined in order of content. In semi-fermented tea and black tea, Ter+theanine, Glu, and Asp were determined in order of content. The rate of essential amino acid in the total content of free amino acid was increased with fermentation. The content of theanine was 1.21% in non fermented tea and 1.50% in black tea. The contents of theanine were increased as tea was more fermented. The content of caffein was 3.57% in non fermented tea and 3.55 ~ 3.60% in semi-fermented tea and black tea. These results were inconsistent in the content of caffein. Five kinds of catechin, that is, cathechin, epigallocathechin, epicathechin, epigallocathechin gallate, and epicathechin gallate were extracted. The content of catechin was 14.18% in non fermented tea, but decreased sharply as tea was more fermented.