Emerging Interconnect and Pb-free Materials for Advanced Packaging Technology: Poster Session
Sponsored by: TMS Functional Materials Division, TMS: Electronic Packaging and Interconnection Materials Committee
Program Organizers: Fan-Yi Ouyang, National Tsing Hua University; C. Robert Kao, National Taiwan University; Albert T Wu, National Central University; Fay Hua, Intel Corporation; Yan Li, Intel Corporation; Babak Arfaei, Binghamton University; Kazuhiro Nogita, The University of Queensland

Tuesday 6:00 PM
February 28, 2017
Room: Hall B1
Location: San Diego Convention Ctr

L-61: Effect of Component Surface Finish on the Thermo-mechanical Reliability of Lead-free High Temperature Solder Alloys: Faramarz Hadian1; Harry Schoeller2; Eric Cotts1; 1Binghamton University; 2Universal Instrument Corporation
    New reliability issues arise in solder joints operating at 200oC, including accelerated growth of intermetallic compounds at metallization/solder interfaces and more rapid coarsening of precipitates. Thus Pb free solder joint performance was investigated in thermal shock excursions between -55oC and 200oC for many different combinations of Pb free solders and surface finishes. These tests were combined with careful microstructural characterization before and after thermal shock, and shear strength measurements. A standard high Pb solder was also subjected to all aspects of the test plan, and thus was utilized as a standard. Sn based solder alloys with solid substitutional additions such as Sb or Bi performed best. Significant variations were observed with changes in surface finishes. Comparisons were made to the performance of Ag-filled epoxy/Au joints.

L-62: Investigation of Melting Behavior and Morphology Change of Sn Nanowires based on Infra-red (IR) Heating Method: Jirui Wang1; Fan Gao1; Zhiyong Gu1; 1University of Massachusetts Lowell
    Infra-red (IR) based soldering method is a non-contact soldering method with focused heating area and short heating duration. The whole soldering process can be done within a few seconds without spreading too much unnecessary heat to the surrounding in order to protect thermal sensitive components or substrates such as polymers or organic molecules. In this study, Sn nanowires were prepared by the electrodeposition method using nanoporous templates and used as a model system to investigate the melting behavior and morphology evolvement of nanowires upon IR heating. Several important factors, including the choice of flux, operating temperature, and heating time, were studied for their effect on solder nanowire melting. The melting behavior and morphology change were examined by field emission scanning electron microscopy (FE-SEM). The process parameters were optimized to obtain uniform and fully reflowed solder balls, which is important for IR-based soldering of nanowire devices.

L-63: Study on Thermomechanical Properties of Graphene-added Solder Paste for Automotive Electronics: Sang Jun Park1; Dong-Yurl Yu1; Kyoung-Ho Kim1; Junghwan Bang1; Soong-Keun Hyun2; Yong-Ho Ko1; 1Korea Institute of Industrial Technology; 2Dept. of Materials Science and Engineering, Inha University
    Recently, in an automotive electronics industry, Pb-based materials have been replaced with Pb-free solder for joining between electronic chips/packages and substrate due to environmental regulations such as the end-of-life vehicle (ELV). When it is compared with consumer electronics, the high reliability for long lifetime of the automotive electronics are required. To improve the reliability of Sn-based Pb-free solders, various studies for solder joint materials, such as Zn-Al and, nanoparticle-added solders, have been proposed. In this study, the thermo-mechanical reliability of graphene-added Sn-3.0wt%Ag-0.5wt%Cu (SAC305) solders were investigated. The weight percentage of the graphene contents was varied from 0 to 0.2 wt%. The prepared solder paste was printed and reflowed with surface-mount technology (SMT) process. Aa thermal shock test was performed and then the joint strength was also measured with a high speed shear test. The thickness of intermetallic compound (IMC) was also observed to investigate the thermal behavior of solder joints.

L-64: Synchrotron X-ray Study of Sn Whisker Growth Induced by Electromigration: Cheng-En Ho1; Wan-Zhen Hsieh1; Pei-Tzu Lee1; Cheng-Hsien Yang1; 1Yuan Ze Uneversity
    Tin (Sn) is a conducting material and the growth of Sn whiskers becomes a serious reliability concern owing to the applications of Sn-based solder and surface finish over the fine-pitch circuits in microelectronic packages. Sn whisker growth refers to a creep phenomenon in which both stress generation and relaxation take place simultaneously. A stress gradient can be generated in a Sn film with the Sn/Cu reaction, providing the driving force of a long-range Sn diffusion needed for whiskering. To advance fundamental understanding of the whiskering mechanism, electromigration testing on a Sn Blech structure is usually employed to accelerate the growth of Sn whiskers. In this study, we conducted an in-situ analysis via synchrotron X-ray radiation and electron backscatter diffraction (EBSD) to measure the local stress level, stress evolution, crystallographic orientation of a Sn Blech structure under electron current stressing, to gain better understanding of Sn whiskers.