• Title/Summary/Keyword: Ag

Search Result 6,008, Processing Time 0.039 seconds

Investigation of Ag Migration from Ag Paste Bump in Printed Circuit Board (Ag Paste bump 구조를 갖는 인쇄회로기판의 Ag migration 발생 안전성 평가)

  • Song, Chul-Ho;Kim, Young-Hun;Lee, Sang-Min;Mok, Jee-Soo;Yang, Yong-Suk
    • Korean Journal of Materials Research
    • /
    • v.20 no.1
    • /
    • pp.19-24
    • /
    • 2010
  • The current study examined Ag migration from the Ag paste bump in the SABiT technology-applied PCB. A series of experiments were performed to measure the existence/non-existence of Ag in the insulating prepreg region. The average grain size of Ag paste was 30 nm according to X-ray diffraction (XRD) measurement. Conventional XRD showed limitations in finding a small amount of Ag in the prepreg region. The surface morphology and cross section view in the Cu line-Ag paste bump-Cu line structure were observed using a field emission scanning electron microscope (FE-SEM). The amount of Ag as a function of distance from the edge of Ag paste bump was obtained by FE-SEM with energy dispersive spectroscopy (EDS). We used an electron probe micro analyzer (EPMA) to improve the detecting resolution of Ag content and achieved the Ag distribution function as a function of the distance from the edge of the Ag paste bump. The same method with EPMA was applied for Cu filled via instead of Ag paste bump. We compared the distribution function of Ag and Cu, obtained from EPMA, and concluded that there was no considerable Ag migration effect for the SABiT technology-applied printed circuit board (PCB).

High-Speed Shear Test Characterization of Sn-Ag-Cu-In Quaternary Solder Joint (Sn-Ag-Cu-In 4원계 무연솔더 조인트의 고속 전단 특성)

  • Kim, Ju-Hyung;Hyun, Chang-Yong
    • Journal of the Microelectronics and Packaging Society
    • /
    • v.21 no.2
    • /
    • pp.91-97
    • /
    • 2014
  • With Pb-free solder joints containing Sn-Ag-Cu-based ternary alloys (Sn-1.0 wt.%Ag-0.5Cu and Sn-4.0Ag-0.5Cu) and Sn-Ag-Cu-In-based quaternary alloys (Sn-1.0Ag-0.5Cu-1.0In, Sn-1.2Ag-0.5Cu-0.4In, Sn-1.2Ag-0.5Cu-0.6In, and Sn-1.2Ag-0.7Cu-0.4In), fracture-mode change, shear strengths, and fracture energies were observed and measured under a high-speed shear test of 500 mm/s. The samples in each composition were prepared with as-reflowed ones or solid-aged ones at $125^{\circ}C$ to 500 h. As a result, it was observed that ductile or quasi-ductile fracture modes occurs in the most of Sn-Ag-Cu-In samples. The happening frequency of a quasi-ductile fracture mode showed that the Sn-Ag-Cu-In joints possessed ductile fracture properties more than that of Sn-3.0Ag-0.5Cu in the high-speed shear condition. Moreover, the Sn-Ag-Cu-In joints presented averagely fracture energies similar to those of Sn-Ag-Cu joints. While maximum values in the fracture energies were measured after the solid aging for 100 h, clear decreases in the fracture energies were observed after the solid aging for 500 h. This result indicated that reliability degradation of the Sn-Ag-Cu-In solder joints might accelerate from about that time.

The Effects of Maternal HBs antigenemia on the Neonatal Health (산모(産母)의 B형 간염(肝炎) Virus 보유(保有)가 신생아(新生兒) 건강(健康)에 미치는 영향(影響))

  • Park, Jung-Han;Yoon, Sung-Do;Kim, Chang-Youn;Lee, Sung-Kwan
    • Journal of Preventive Medicine and Public Health
    • /
    • v.17 no.1
    • /
    • pp.47-55
    • /
    • 1984
  • To study the risk factors associated with maternal HBsAg carrier and the effects of maternal HBs antigenemia on the neonatal health, sera of 729 pergnant women admitted to the Keimyung University Hospital for delivery during the period of February 1-May 30. 1982 were tested for HBsAg by RPHA method and for anti-HBs by PHA method. Among them 43 women (5.9%) had HBsAg and 246 women (33.7%) had anti-HBs giving an infection rate of 39.6%. The interview data for 43 HBsAg positive mothers and randomly selected 210 HBsAg negative mothers showed a statistically significant association between acupuncture history and HBsAg positive rate (p<0.005) which suggest that acupuncture might have contributed significantly to the propagation of viral hepatitis in Korea. The living standard of HBsAg positive mothers was generally lower than that of HBsAg negative mothers which supports the hypothesis that environmental factors are associated with viral hepatitis B infection. None of the 43 neonates born to HBsAg positive mothers had HBsAg in their cord blood. Three months after birth, 35 out of 43 infants were retested and only one infant became HBsAg positive. At six months of age, 32 out of 35 infants were retested and none of them were HBsAg positive except the same infant who was positive at three months. Among 20 control infants of HBsAg negative mothers, all of them were HBsAg negative at three and six months follow-up. These findings are not consistent with the supposition that perinatal infection is a main route of viral hepatitis B transmission in south-east Asia including Korea. HBsAg positive mothers had significantly higher rate of premature delivery (27.9%) than HBsAg negative mothers (11.7%) (p<0.05). Also, the low birthweight incidence rate was higher among HBsAg positive mothers (23.3%) than negative mothers (14.1%) but this was not statistically significant (P=0.16). The premature rupture of membrane was more frequent among HBsAg positive mothers (25.5%) than negative mothers (11.1%) (p<0.05). There were no significant differences in the stillbirth rate and incidence of congenital anomalies between HBsAg positive and negative groups. It was not clarified in this study due to small sample size whether higher incidence of premature delivery and premature rupture of membranes among HBsAg positive mothers was due to HBs antigenemia per so or their lower living standard than HBsAg negative mothers.

  • PDF

Effects of Ag on the Characteristics of Sn-Pb-Ag Solder for Photovoltaic Ribbon (태양광 리본용 Sn-Pb-Ag 솔더의 특성에 미치는 Ag의 영향)

  • Son, Yeon-Su;Cho, Tae-Sik
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.28 no.5
    • /
    • pp.332-337
    • /
    • 2015
  • We have studied the effects of Ag on the characteristics of $Sn_{60}Pb_{40}Ag_x$ (wt%) solder for photovoltaic ribbon. Ag atoms in the solder formed an alloy phase of $Ag_3Sn$ after reacting with some part of Sn atoms, while they did not react with Pb atoms, but decreased the mean size of Pb solid phase. The enhancement of peel strength between solar cell and ribbon is an important part in the developments of long-lifespan solar module. The peel strength of the solder ribbon of $Sn_{60}Pb_{40}$ (wt%) was $169N/mm^2$, and it was largely enhanced by adding a small amount of Ag atoms. The maximum peel strength was $295N/mm^2$ in the solder ribbon of $Sn_{60}Pb_{40}Ag_2$ (wt%). This result is caused by the high binding energy of 162.9 kJ/mol between Ag atoms in the solder and Ag atoms in Ag sheet.

Facile Preparation of Nanosilver-decorated MWNTs Using Silver Carbamate Complex and Their Polymer Composites

  • Park, Heon-Soo;Gong, Myoung-Seon
    • Bulletin of the Korean Chemical Society
    • /
    • v.33 no.2
    • /
    • pp.483-488
    • /
    • 2012
  • We successfully decorated multi-wall carbon nanotubes (MWNTs) with silver by reacting Ag-NPs with thiolfunctionalized MWNT-SH. Ag alkylcarbamate complex was used as an Ag precursor. Uniform Ag-NPs (5-10 nm) were effectively prepared by microwaving within 60 s using 1-amino-4-methylpiperazine (AMP), which acts as a reaction medium, reducing agent, and stabilizer. The MWNTs were functionalized with 2-aminoethanethiol. Exploiting the chemical affinity between thiol and Ag-NPs, Ag-MWNT nanohybrids were obtained by spontaneous chemical adsorption of MWNT-SH to Ag through Ag-S bonds. The Ag-S-MWNTs were characterized by TGA, XRD, and TEM to confirm that Ag-NPs were uniformly decorated onto the MWNTs. The Ag-S-MWNTs were then employed as conducting filler in epoxy resin to fabricate electrically conducting polymer composites. The electrical properties of the composites were measured and compared with that containing MWNT-SH. The electrical conductivity of composites containing 0.4 wt % Ag-S-MWNT was four orders of magnitude higher than those containing same content of MWNT-SH, confirming Ag-S-MWNT as an effective conducting filler.

Preparation of Ag-PS and Ag-PSS Particles by ${\gamma}$-Irradiation and Their Antimicrobial Efficiency against Staphylococcus aureus ATCC 6538 and Klebsiella pneumoniae ATCC 4352

  • Oh Seong-Dae;Byun Bok-Soo;Lee Seung-Ho;Choi Seong-Ho
    • Macromolecular Research
    • /
    • v.14 no.2
    • /
    • pp.194-198
    • /
    • 2006
  • Polystyrene, PS, particles of 450 nm diameter and poly(styrene-co-styrene sulfonate), PSS, particles of 140-160 nm diameter were prepared by emulsifier-free emulsion polymerization. The surfaces of the PS and PSS particles were coated with Ag nanoparticles for the application of antimicrobial agents by reduction of Ag ions using ${\gamma}$-irradiation. The Ag-PS and Ag-PSS were characterized by High-Resolution Transmittance Electron Microscopy (HR-TEM), Field-Emission Scanning Electron Microscopy (FE-SEM), and Energy Dispersive X-ray Spectroscopy (EDXS). The HR-TEM and EDXS data showed that the Ag nanoparticles were loaded on the surface of the PS and PSS particles, respectively. The antimicrobial efficiency of the Ag-PS and Ag-PSS particles (0.4 g) with ca. 100 ppm Ag, which was coated onto yam (KS K 0905-1996 rule), was tested against Staphylococcus aureus ATCC 6538 and Klebsiella pneumoniae ATCC 4352 after 100 washing cycles (KS K 0432-1999 rule). The antimicrobial efficiency of the Ag-PS particles against Staphylococcus aureus ATCC 6538 and Klebsiella pneumoniae ATCC 4352 was 99.9% after 100 cycles washing., confirming that the Ag-PS particles can be used as antimicrobial agents.

The Study on the Solidification Path of the Near Eutectic Compositions in Sn-Ag-Cu Lead-Free Solder System (Sn-Ag-Cu 삼원계 공정점 근처 여러 조성들의 미세조직 연구)

  • 김현득;김종훈;정상원;이혁모
    • Proceedings of the International Microelectronics And Packaging Society Conference
    • /
    • 2003.11a
    • /
    • pp.114-117
    • /
    • 2003
  • 본 연구에서는 계산을 통해 나온 Sn-Ag-Cu 삼원계 공정점(Sn-3.7Ag-0.9Cu)을 바탕으로 그 근처의 응고경로가 다른 6가지 조성(Sn-4.6Ag-0.4Cu, Sn-4.9Ag-1.0Cu, Sn-3.9Ag-1.3Cu, Sn-2.2Ag-1.2Cu, Sn-2Ag-0.7Cu, Sn-2.7Ag-0.3Cu)에 대한 솔더합금의 미세조직을 관찰하였다. 응고경로는 $L\;\rightarrow\;L+Primary\;\rightarrow\;L+Primary+Secondary\;\rightarrow\;Ternary\;Eutectic+Primary+Secondary$로 되며 6가지 경우를 예상할 수 있다 솔더합금의 미세조직은 느린 냉각으로 인하여 빠른 냉각, 보통 냉각에 비해 상대적으로 커다란 $\beta-Sn$ dendrite를 보였고 $Ag_3Sn,\;Cu_6Sn_5$과는 다르게 $\beta-Sn$는 약 $30^{\circ}C$의 과냉(DSC분석)이 존재하게 되어 Sn-4.6Ag-0.4Cu의 경우에는 $Ag_3Sn$상이, Sn-2.2Ag-1.2Cu의 경우에는 $Cu_6Sn_5$가 과대성장을 하였다. 솔더의 기계적 특성을 살펴보고자 Cu 기판위에서 각 조성의 솔더볼을 솔더링한 후 다양한 냉각 속도를 적용하여 reflow 솔더링을 하고 솔더/기판 접합에 대한 전단 강도 시험을 실시했다. 냉각 속도가 빠를수록 $\beta-Sn$의 dendrite가 미세해져서 높은 전단 강도를 보였고 6가지 조성의 솔더볼중 공정조직 분율이 낮은 Sn-2Ag-0.7Cu 조성의 경우에서 낮은 전단 강도가 나타났다.

  • PDF

Study on the prevalence of HBV Ag and HBV markers revealed through preemployment examination in asymptomatic healthy persons (직장(職場) 채용(採用) 신체검사(身體檢査)에서 나타난 B형(型) 바이러스 간염(肝炎) 검사성적(檢査成績)에 관(關)한 고찰(考察))

  • Kim, Joo-Ja
    • Journal of Preventive Medicine and Public Health
    • /
    • v.17 no.1
    • /
    • pp.203-210
    • /
    • 1984
  • Primary screening test for serum HBsAg by RPHA from 4,805 persons who were clinically well through preemployment examination for the period of one calendar year of 1983 revealed 476 (9.9%) positive individual carriers. There were no significant differences in distribution of positives of serum HBsAg by age group, profession, or province area. Among positives of serum HBsAg, 356 (74.8%) showed normal findings and 120 (25.2%) showed abnormal findings in liver function test, respectively. Radioimmunoassay was done in 169 positives of HBsAg and RIA detected 10 negative persons who were positive by RPHA revealing 5.9% of false positive rate and 94.1% of sensitivity of RPHA. In RIA profile of HBV markers, pattern I (HBsAg+, Anti-HBe+) was 46.6%, pattern II (HBsAg+, HBeAg+) was 33.3%, pattern III (HBsAg+only) was 18.3%, pattern IV (HBsAg+, HBeAg+, Anti-HBs+) was 1.3%, pattern V (HBsAg+, HBeAg+, Anti-HBe+) was 0.6%, respectively. There were no positives of HBsAg among 10 persons who were negatives of HBsAg by RIA.

  • PDF

The Effect of Electroplating Parameters on the Compositions and Morphologies of Sn-Ag Bumps (Sn-Ag 범프의 조성과 표면 형상에 영향을 미치는 도금 인자들에 관한 연구)

  • Kim, Jong-Yeon;Yoo, Jin;Bae, Jin-Soo;Lee, Jae-Ho
    • Journal of the Microelectronics and Packaging Society
    • /
    • v.10 no.4
    • /
    • pp.73-79
    • /
    • 2003
  • With the variation of Ag concentration in bath, current density, duty cycle, additive and agitation for electroplating of Sn-Ag solder, the compositions and the morphologies of solder were studied. It was possible to controll Ag content in Sn-Ag solder by varying Ag concentration in bath and current density. The microstructure size of Sn-Ag solder decreased with increasing current density. Duty cycle of pulse electroplating and quantity of additive affected on Ag content of deposit and surface roughness. In this work eutectic Sn-Ag solder bumps with fine pitch of 30 $\mu\textrm{m}$ and height of 15 $\mu\textrm{m}$ was formed successfully. The Ag content of electrodeposited solder was confirmed by EDS and WDS analyses and the surface morphologies was analyzed by SEM and 3D surface analyzer.

  • PDF

Single crystal growth and structure analysis of superionic conductor ${\beta}-Ag_3SI$ (초이온도전체 ${\beta}-Ag_3SI$의 단결정 육성과 결정구조 해석)

  • Nam Woong Cho;Kwang Soo Yoo;Hyung Jin Jung
    • Journal of the Korean Crystal Growth and Crystal Technology
    • /
    • v.4 no.1
    • /
    • pp.63-70
    • /
    • 1994
  • Single crystals of the superionic conductor ${\beta}-Ag_3SI$ were prepared by thermal treatmentr from the reactant mixture of AgI and $Ag_2S$. The growing single crystals were made to spherical shape of $200{mu}m$ in diameter. The detailed structures analyses revealed that $Ag^+$ in ${\beta}-Ag_3SI$ distribute on 12h site of 4-coordination inpreference to 3c site of 6-coordination. The effective one-particle potential (o.p.p.). of $Ag^+$ along [110] direction was evaluated from the probability density function(p.d.f.) Activation energy calculated from the o.p.p. curve has been found to be 0.012 eV for the diffusion of $Ag^+$ on (001) plane in the ${\beta}-Ag_3SI$ structure.

  • PDF