• Title/Summary/Keyword: soldering process

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Tafel Characteristics by Electrochemical Reaction of SnAgCu Pb-Free Solder (SnAgCu계 무연솔더의 전기화학적 반응에 따른 타펠 특성)

  • Hong Won Sik;Kim Kwang-Bae
    • Korean Journal of Materials Research
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    • v.15 no.8
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    • pp.536-542
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    • 2005
  • Recently European Council(EU) published the RoHS(restriction of the use of certain hazardous substances in electrical and electronic equipment) which is prohibit the use of Pb, Hg, Cd, $Cr^{+6}$, PBB or PBDE in the electrical and electronic equipments. So EU member States shall ensure that, from 1 July 2006, new electrical and electronic equipment put on the market does not contain 6 hazardous substances. The one of the most important in electronics manufacturing process is soldering. Soldering process use the chemical substances which are applied in fluxing and cleaning processes and it can generate the malfunction of electronics caused by corrosion in the fields conditions. Therefore this study researched on the polarization and Tafel properties of Sn40Pb and Sn3.0Ag0.5Cu(SAC) solder based on the electrochemical theory. We prepared SnPb specimens which was aged in $150^{\circ}C,\;180^{\circ}C$ for 15 minutes ana Sn3.0Ag0.5Cu specimens that was aged in $180^{\circ}C,\;220^{\circ}C$ for 10 minutes. Experimental polarization curves were measured in distilled ionized water and $3.5 wt\%$, 1 mole NaCl electrolyte of $40^{\circ}C$, pH 7.5. Ag/AgCl and graphite were utilized by reference and counter electrode, respectively. To observe the electrochemical reaction, polarization test was conducted from -250 mV to +250 mV. From the polarization curves that were composed of anodic and cathodic curves, we obtained Tafel slop, reversible electrode potential(Ecorr) and exchange current density(Icorr). In these results, corrosion rate for two specimen were compared Sn3.0Ag0.5Cu with SnPb solders

Application of the Axiomatic Design Methodology to the Design of PBGA Package with Polyimide Coating Layer

  • Yang, Ji-Hyuck;Lee, Kang-Yong;Dong, C. Y.
    • Journal of Mechanical Science and Technology
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    • v.18 no.9
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    • pp.1572-1581
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    • 2004
  • The purposes of the paper are to apply the axiomatic design methodology to the design of PBGA package with polyimide coating under hygrothermal loading in the IR soldering process and to suggest more reliable design conditions by stress analysis. The analysis model is a 256-pin perimeter Plastic Ball Grid Array (PBGA) package with the polyimide coating surrounding chip and above surface of BT-substrate. The polyimide coating is suggested to depress the maximum stresses occurred on the stress concentration positions. The axiomatic design methodology is proved to be useful to find the more reliable design conditions for PBGA package. Finally, the optimal values of design variables to depress the stress in the PBGA package are obtained.

Trasient Liquid Phase bonding for Power Semiconductor (전력반도체 패키징을 위한 Transient liquid phase 접합 기술)

  • Roh, Myong-Hoon;Nishikawa, Hiroshi;Jung, Jae Pil;Kim, Wonjoong
    • Journal of the Microelectronics and Packaging Society
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    • v.24 no.1
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    • pp.27-34
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    • 2017
  • Recently, a demand in sustainable green technologies is requiring the lead free bonding for high power module packaging due to the environmental pollution. The Transient-liquid phase (TLP) bonding can be a good alternative to a high Pb-bearing soldering. Basically, TLP bonding is known as the combination of soldering and diffusion bonding. Since the low melting temperature material is fully consumed after TLP bonding, the remelting temperature of joint layer becomes higher than the operating temperature of the power module. Also, TLP bonding is cost-effective process than metal nanopaste bonding such as Ag. In this paper, various TLP bonding techniques for power semiconductor were described.

Modeling of Soldering Proess using Longitudinal Thermosonic Method (종방향 열초음파 방법을 이용한 솔더링 공정의 모델링)

  • 김정호;이지혜;유중돈;최두선
    • Proceedings of the KWS Conference
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    • 2003.05a
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    • pp.224-227
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    • 2003
  • The longitudinal thermosonic bonding method is investigated in this work for its application to the soldering process for electronic packaging. The effect of the ultrasonic is analyzed through lumped modeling, and the material properties of a viscoelastic model are measured experimentally. The thermosonic bonding method is verified by inserting the Cu pin and Au bump into solder block. As the solder thickness decreases, temperature of the solder is calculated to increase rapidly because of larger strain. Localized heating due to ultrasonic vibration is observed to melt the solder near the pin, which is adequate to the high density electronic package and Pb-free solder having high melting temperature.

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A study on the tensile strength of flow-soldered joint using low residue flux (저잔사 플럭스를 사용한 플로 솔더링부의 인장특성 연구)

  • 장인철;최명기;신영의;정재필;서창제
    • Journal of Welding and Joining
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    • v.17 no.1
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    • pp.77-81
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    • 1999
  • Through-hole PCB(Printed Circuit Board) was soldered by flow soldering process using cleaning or noncleaning fluxes. Preheating temperature and conveyor speed were changed in the range of 323∼413K and 0.3∼2m/min respectively. The soldered joints were tensile tested in order to evaluated bonding strength. As experimental results, relatively high tensile fracture load, 120∼140N, were obtained in case of preheating temperature of 383K, and conveyor speed was 0.6∼1.0 m/min. Fractured surfaces of higher tensile strength show some dimple area, while those of lower tensile fracture load show brittle fracture.

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Manufacturing of Composite Solders by an In-situ Process (In-situ 공정에 의한 복합솔더 제조)

  • Hwang, Seong-Yong;Lee, Joo-Won;Lee, Zin-Hyoung
    • Journal of Korea Foundry Society
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    • v.22 no.1
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    • pp.35-41
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    • 2002
  • To improve the reliability of solder joints, a composite solder which consists of solder matrix and intermetallic reinforcements was manufactured by a new method. The cast ingot of Sn-6.9Cu-2.9Ag alloy had primary Cu6Sn5 intermetallics in the form of dendrites. After rolling the ingot, the intermetallic dendrites were crushed into fine particles and distributed uniformly throughout the solder matrix. As the rolled strips became thinner, the average size of the crushed particles reached a critical size which did not decrease any more by further rolling. The critical size was nearly the same as the average width of intermetallic dendrite trunk. The crushed intermetallic particles did not melt and remained in solid state during reflow soldering due to their high meltingterm-perature. The coarsening and gravitational segregation of the particles were observed during reflow soldering.

Soldering characteristics of Ag-Pd electrodes in relationship to differing particle size of LTCC substrate (LTCC 기판의 Particle Size 에 따른 Ag-Pd 전극의 Soldering 특성 변화)

  • 조현민;유명재;박종철
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • 2002.05a
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    • pp.130-133
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    • 2002
  • Solder leaching resistance of the metal electrode is an important factor with regard to adhesion properties of ceramic substrate. In the Low Temperature Co-fired Ceramics (LTCC), Ag-Pd or Ag-Pt pastes are used instead of pure Ag paste to prevent leaching. Solder leaching behavior of the Ag-Pd paste in relation to LTCC raw material powder size was investigated. First fabrication of LTCC green tape with different particle size was done. LTCC substrates with Ag-Pd electrode were prepared using conventional multilayer ceramic process. Dipping test was performed to test solder leaching behavior of the electrode. Ag-Pd electrode on LTCC substrate with smaller particle size achieved higher solder leaching resistance.

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Long Duration Withstand Current Characteristics of ZnO Varistors (ZnO 바리스터 소자의 장시간 방전내량 특성)

  • Cho, Han-Goo;Yoon, Han-Soo;Kim, Suk-Soo;Han, Se-Won;Yu, Kun-Yang;Lee, Yong-Sun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.07a
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    • pp.544-545
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    • 2005
  • This paper describes the long duration withstand current characteristics of ZnO varistors. Two ZnO varistors were manufactured with general ceramic production methods and three abroad varistors were also prepared to be compared. During long duration withstand test, sample 1 was destroyed at 4th impulse current but the rest passed test. Before and After the test, the residual voltage variation of varistors passed was below 5%. According to the test results, it is thought that the manufacturing process such as insulating coating, sintering condition and soldering method should be improved.

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Activation Energy and Interface Reaction of Sn-40Pb/Cu & Sn-3.0Ag-0.5Cu/Cu (Sn-40Pb/Cu 및 Sn-3.0Ag-0.5Cu/Cu 접합부 계면반응 및 활성화에너지)

  • Kim, Whee-Sung;Hong, Won-Sik;Park, Sung-Hun;Kim, Kwang-Bae
    • Korean Journal of Materials Research
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    • v.17 no.8
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    • pp.402-407
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    • 2007
  • In electronics manufacturing processes, soldering process has generally been used in surface mounting technology. Because of environmental restriction, lead free solders as like a SnAgCu ternary system are being used widely. After soldering process, the formation and growth of intermetalic compounds(IMCs) are formed in the interface between solder and Cu substrate as follows isothermal temperature and time. In this studies, therefore, we investigated the effects of the Cu substrate thickness on the IMC formation and growth of Sn-40Pb/Cu and Sn-3.0Ag-0.5Cu/Cu solder joints, respectively. The effect of the Cu thickness in PCB Cu pad and pure Cu plate was analyzed as measuring of thickness of each IMC. After solder was soldered on PCB and Cu plate which have different Cu thickness, we measured the IMC thickness in solder joints respectively. Also we compared with the effectiveness of Cu thickness on the IMC growth. From these results, we calculated the activation energy.