• Title/Summary/Keyword: Ball Grid Array(BGA)

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Effect of Reflow Number on Mechanical and Electrical Properties of Ball Grid Array (BGA) Solder Joints (BGA 솔더 접합부의 기계적.전기적 특성에 미치는 리플로우 횟수의 효과)

  • Koo, Ja-Myeong;Lee, Chang-Yong;Jung, Seung-Boo
    • Journal of the Microelectronics and Packaging Society
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    • v.14 no.4
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    • pp.71-77
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    • 2007
  • In this study, the mechanical and electrical properties of three different ball grid array (BGA) solder joints, consisting of Sn-37Pb, Sn-3.5Ag and Sn-3.5Ag-0.75Cu (all wt.%), with organic solderability preservative (OSP)-finished Cu pads were investigated as a function of reflow number. Based on scanning electron microscopy (SEM) analysis results, a continuous $Cu_6Sn5$, intermetallic compound (IMC) layer was formed at the solder/substrate interface, which grew with increasing reflow number. The ball shear testing results showed that the shear force peaked after 3 reflows (in case of Sn-Ag solder, 4 reflows), and then decreased with increasing reflow number. The electrical property of the joint gradually decreased with increasing reflow number.

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Development of Copper Cored Solder Ball(CCSB) by Sn-Ag-Cu Alloy Plating Process

  • Lee, Deok-Haeng;Jeong, Un-Seok;Kim, Jong-Uk;Kim, Pan-Su
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • pp.284-284
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    • 2015
  • 반도체 Ball Grid Array(BGA)에 사용되던 종래의 Solder Ball은 Sn96.3 Ag3.0 Cu0.7의 용융솔더를 이용하여 제작하고 있다. 이는 SMT Reflow공정에서 BGA Ball의 퍼짐현상으로 인해 원래의 Ball Height에 영향을 미쳐 접합불량의 원인이 되고 있다. 이러한 문제를 해결하기 위해 Copper Core Ball위에 SnAgCu 삼원합금도금공정을 이용해 문제점을 해결하고자 했으며, 본 실험을 통해 구현한 CCSB를 이용해 SMT Reflow를 진행한 결과 종래의 BGA Ball보다 우수한 효과를 확인할 수 있었다.

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Effect of Test Parameter on Ball Shear Properties for BGA and Flip Chip Packages (BGA 및 Flip Chip 패키지의 볼전단 특성에 미치는 시험변수의 영향)

  • Gu, Ja-Myeong;Jeong, Seung-Bu
    • Proceedings of the KWS Conference
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    • pp.19-21
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    • 2005
  • The ball shea. tests for ball grid array (BGA) and flip chip packages were carried out with different displacement rates to find out the optimum condition of the displacement rate for this test. The BGA packages consisted of two different kinds of solder balls (eutectic Sn-37wt.%Pb and Sn-3.5wt.%Ag) and electroplated Au/Ni/Cu substrate, whereas the flip chip package consisted of electroplated Sn-37Pb solder and Cu UBM. The packages were reflowed up to 10 times, or aged at 443 K up to 21 days. The variation of the displacement rate resulted in the variations of the shear properties such as shear force, displacement rate at break, fracture mode and strain rate sensitivity. The increase in the displacement rate led to the increase of the shear force and brittleness of solder joints.

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3-Dimensional Micro Solder Ball Inspection Using LED Reflection Image

  • Kim, Jee Hong
    • International journal of advanced smart convergence
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    • v.8 no.3
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    • pp.39-45
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    • 2019
  • This paper presents an optical technique for the three-dimensional (3D) shape inspection of micro solder balls used in ball-grid array (BGA) packaging. The proposed technique uses an optical source composed of spatially arranged light-emitting diodes (LEDs) and the results are derived based on the specular reflection characteristics of the micro solder balls for BGA A vision system comprising a camera and LEDs is designed to capture the reflected images of multiple solder balls arranged arbitrarily on a tray and the locations of the LED point-light-source reflections in each ball are determined via image processing, for shape inspection. The proposed methodology aims to determine the presence of defects in 3D BGA shape using the statistical information of the relative positions of multiple BGA balls, which are included in the image. The presence of the BGA balls with large deviations in relative position imply the inconsistencies in their shape. Experiments were conducted to verify that the proposed method could be applied to inspection without sophisticated mechanism and productivity problem.

High Speed Measurement of Ball Height Data for Ball Grid Arrays (BGA(Ball Grid Array) 높이 데이타의 고속 측정)

  • Cho Tai-Hoon;Joo Hyo-Nam
    • Journal of the Semiconductor & Display Technology
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    • v.5 no.1
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    • pp.1-4
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    • 2006
  • Recently, Ball Grid Arrays(BGAs) are getting used more frequently for a package type. The connectors on a BGA consist of a large number of small solder balls in a grid shape on its bottom side. However, since balls of BGAs mounted on PCBs are not visible, inspection before mounting them is indispensable. High speed non-contact 3D measurement technologies are necessary far real-time measurement of ball height, the most important inspection item. In this paper, an accurate 3D data acquisition system for BGAs is proposed that can acquire 3D profile at high speed using a 3D smart camera and laser slit ray projection. Some clipping and morphological filtering operations are employed to remove spiky error data, which occur due to reflections from some ball area to camera direction.

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Evaluation of Thermal Deformation Model for BGA Packages Using Moire Interferometry

  • Joo, Jinwon;Cho, Seungmin
    • Journal of Mechanical Science and Technology
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    • v.18 no.2
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    • pp.230-239
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    • 2004
  • A compact model approach of a network of spring elements for elastic loading is presented for the thermal deformation analysis of BGA package assembly. High-sensitivity moire interferometry is applied to evaluate and calibrated the model quantitatively. Two ball grid array (BGA) package assemblies are employed for moire experiments. For a package assembly with a small global bending, the spring model can predict the boundary conditions of the critical solder ball excellently well. For a package assembly with a large global bending, however, the relative displacements determined by spring model agree well with that by experiment after accounting for the rigid-body rotation. The shear strain results of the FEM with the input from the calibrated compact spring model agree reasonably well with the experimental data. The results imply that the combined approach of the compact spring model and the local FE analysis is an effective way to predict strains and stresses and to determine solder damage of the critical solder ball.

Effect of Reflow Time on Mechanical and Electrical Properties of Sn-3.5Ag Solder Joints (Sn-3.5Ag 솔더 접합부의 기계적.전기적 특성에 미치는 리플로우 시간의 효과)

  • Gu Ja-Myeong;Mun Jeong-Hun;Jeong Seung-Bu
    • Proceedings of the KWS Conference
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    • pp.36-38
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    • 2006
  • We investigated that the metallurgical, mechanical and electrical properties of the Sn-3.SAg/Cu ball grid array (BGA) solder joints at a reflow temperature of $255^{\circ}C$ for different reflow times of 10, 60, 300 and 1800 s. Two different intermetallic compound (IMC) layers, consisting of scallop-shaped $Cu_6Sn_5$ and very thin $Cu_3Sn$, formed at the solder/substrate interface, and their thicknesses increased with increasing reflow time. The shear force peaked after reflow for 60 s, and then significantly decreased with increasing reflow time. The fracture occurred along the solder ball in the initial reflow, but the fraction of the brittle fracture increased with increasing reflow time. The IMC growth and the volume of Cu dissolved in the solder balls affected the electrical property.

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Fabrication of Test Socket from BeCu Metal Sheet (BeCu 금속박판을 이용한 테스트 소켓 제작)

  • Kim, Bong-Hwan
    • Journal of Sensor Science and Technology
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    • v.21 no.1
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    • pp.34-38
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    • 2012
  • We have developed a cost effective test socket for ball grid array(BGA) integrated circuit(IC) packages using BeCu metal sheet as a test probe. The BeCu furnishes the best combination of electrical conductivity and corrosion resistance. The probe of the test socket was designed with a BeCu cantilever. The cantilever was designed with a length of 450 ${\mu}m$, a width of 200 ${\mu}m$, a thickness of 10 ${\mu}m$, and a pitch of 650 ${\mu}m$ for $11{\times}11$ BGA. The fabrication of the test socket used techniques such as through-silicon-via filling, bonding silicon wafer and BeCu metal sheet with dry film resist(DFR). The test socket is applicable for BGA IC chip.

Reaction Characteristics between In-l5Pb-5Ag Solder and Au/Ni Surface Finish and Reliability Evaluation of Solder Joint (In-l5Pb-5Ag 솔더와 Au/Ni Surface Finish와의 반응 특성 및 접합 신뢰성 평가)

  • 이종현;엄용성;최광성;최병석;윤호경;박흥우;문종태
    • Journal of the Microelectronics and Packaging Society
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    • v.9 no.4
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    • pp.1-9
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    • 2002
  • The metallurgical reaction properties between the pad consisted of 0.5 $\mu\textrm{m}$Au/5 $\mu\textrm{m}$Ni/Cu layers on a conventional ball grid array (BGA) substrate and In-15 (wt.%)Pb-5Ag solder ball were characterized during the reflow process and solid aging. During the reflow process of 1 to 5 minutes, it was observed that thin $AuIn_2$ or Ni-In intermetallic layer was formed at the interface of solder/pad. The dissolution rate of the Au layer into the molten solder was about $2\times 10^{-3}$ $\mu\textrm{m}$/sec which is remarkably low in comparison with a eutectic Sn-37Pb solder. After solid aging treatment for 500 hrs at $130^{\circ}C$, the thickness of $Ni_{28}In_{72}$ intermetallic layer was increased to about 3 $\mu\textrm{m}$ in all the conditions nevertheless the initial reflow time was different. These result show that In atoms in the solder alloy were diffused through the $AuIn_2$ phase to react with underlaying Ni layer during solid aging treatment. From the microstructural observation and shear tests, the reaction properties between In-15Pb-5Ag alloy and Au/Ni surface finish were analyzed not to trigger Au-embrittlement in the solder joints unlike Sn-37Pb composition.

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Effects of Graphene Oxide Addition on the Electromigration Characteristics of Sn-3.0Ag-0.5Cu Pb-free Solder Joints (Graphene Oxide 첨가에 따른 Sn-3.0Ag-0.5Cu 무연솔더 접합부의 Electromigration 특성 분석)

  • Son, Kirak;Kim, Gahui;Ko, Yong-Ho;Park, Young-Bae
    • Journal of the Microelectronics and Packaging Society
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    • v.26 no.3
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    • pp.81-88
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    • 2019
  • In this study, the effects of graphene oxide (GO) addition on electromigration (EM) lifetime of Sn-3.0Ag-0.5Cu Pb-free solder joint between a ball grid array (BGA) package and printed circuit board (PCB) were investigated. After as-bonded, $(Cu,Ni)_6Sn_5$ intermetallic compound (IMC) was formed at the interface of package side finished with electroplated Ni/Au, while $Cu_6Sn_5$ IMC was formed at the interface of OSP-treated PCB side. Mean time to failure of solder joint without GO solder joint under $130^{\circ}C$ with a current density of $1.0{\times}10^3A/cm^2$ was 189.9 hrs and that with GO was 367.1 hrs. EM open failure was occurred at the interface of PCB side with smaller pad diameter than that of package side due to Cu consumption by electrons flow. Meanwhile, we observed that the added GO was distributed at the interface between $Cu_6Sn_5$ IMC and solder. Therefore, we assumed that EM reliability of solder joint with GO was superior to that of without GO by suppressing the Cu diffusion at current crowding regions.