Influence of minor Zn addition on the microstructural stability of Sn-0.7 wt% Cu solder after aging and electromigration

Orientador(a) (dc.contributor.advisor)Rhod, Eduardo Luis
Orientador(a) (dc.contributor.advisor)Jung, Seung-Boo
Orientador(a) (dc.contributor.advisor)Kim, Yongil
Lattes Orientador(a) (dc.contributor.advisorLattes)http://lattes.cnpq.br/2146647990461845pt_BR
Autor(a) (dc.contributor.author)Ilha, Bernardo Bortolotto
Autor(a) Lattes (dc.contributor.authorLattes)http://lattes.cnpq.br/2013974785375760pt_BR
Data de Disponibilização (dc.date.accessioned)2018-10-03T13:26:39Z
dc.date.available (dc.date.available)2018-10-03T13:26:39Z
Data da defesa / Data do evento (dc.date.issued)2018-01-16
Resumo (dc.description.resumo)The aging and electromigration (EM) effects were evaluated when up to 0.19 wt.% Zn was added to Sn-0.7 wt.% Cu solder. Currently, the Sn-0.7 wt.% Cu solder is being widely used in the electronic industries due to its advantages of low cost and high temperature applications. However, its usage is also limited by detrimental properties – for instance, when compared to SAC305, Sn-0.7 wt.% Cu solder has lower electromigration life time, shear strength and drop reliability. Minor Zn alloying to Pb-free solders reportedly enhances some of their properties, e.g.: stabilization of bulk microstructures by decreasing undercooling; formation of a thin interfacial diffusion barrier and, thereby, suppressing Cu3Sn and Cu6Sn5 interfacial IMC growth rate and retarding under bump metallurgy (UBM) diffusion through the solder; and also, compensation for Sn self-diffusion due to reverse polarity effect. In this research, the aging and EM effects are assessed when 0.09, 0.16 and 0.19 wt.% Zn were added to Sn-0.7 wt.% Cu solder. The samples underwent up to 500 h of isothermal aging at temperatures of 125, 150 and 175 °C, and EM samples underwent up to 200 h of stressing at a constant temperature of 150 °C and current of 3.25 A. Solder balls were fabricated on a BGA structure for the aging tests, and for the EM tests, a pair of solders was assembled in a daisy-chain structure with organic solderability preservative (OSP) and electroless nickel immersion gold (ENIG) surface finishes. The microstructural evolution and compositional distribution analyses were carried out using optical microscope with brightfield and cross polarized light, scanning electron microscope (SEM), energy dispersive spectrometer (EDS), electron probe micro analyzer (EPMA), and electron backscattered diffraction (EBSD). The addition of Zn suppresses the formation of Cu3Sn IMC and the total interfacial IMC thickness upon aging, and the samples with ENIG had smaller IMC thickness than OSP surface finish. In addition, the grains' microstructure becomes less interlaced and more stable, indicating lower undercooling. The electromigration effects on the microstructure is mainly governed by the relative orientation between the c-axis of Sn grains and the direction of current flow. When parallel, allows cathode UBM and alloying elements diffusion through the solder and formation of IMC, and, when transverse, inhibits this diffusion leading to failure by void formation at the anode UBM/solder interface due to depletion of the UBM and slow Sn self-diffusion.en
Agência de fomento (dc.description.sponsorship)UNISINOS - Universidade do Vale do Rio dos Sinospt_BR
URI (dc.identifier.uri)http://www.repositorio.jesuita.org.br/handle/UNISINOS/7322
Idioma (dc.language)pt_BRpt_BR
Nome da instituição (dc.publisher)Universidade do Vale do Rio dos Sinospt_BR
País da Instituição (dc.publisher.country)Brasilpt_BR
Departamento (dc.publisher.department)Escola Politécnicapt_BR
Sigla da Instituição (dc.publisher.initials)Unisinospt_BR
Programa (dc.publisher.program)Programa de Pós-Graduação em Engenharia Elétricapt_BR
Direitos de acesso ao documento (dc.rights)openAccesspt_BR
Assunto (dc.subject)Sn solderen
Assunto (dc.subject)Zn alloyingen
Assunto (dc.subject)Isothermal agingen
Assunto (dc.subject)Electromigrationen
Tema (CNPq) (dc.subject.cnpq)ACCNPQ::Engenharias::Engenharia Elétricapt_BR
Título (dc.title)Influence of minor Zn addition on the microstructural stability of Sn-0.7 wt% Cu solder after aging and electromigrationpt_BR
Tipo de arquivo (dc.type)Dissertaçãopt_BR

Arquivos

Pacote original

Agora exibindo 1 - 1 de 1
Carregando...
Imagem de Miniatura
Nome:
Bernardo Bortolotto Ilha_.pdf
Tamanho:
33.56 MB
Formato:
Adobe Portable Document Format
Descrição:
microstructural_stability

Licença do pacote

Agora exibindo 1 - 1 de 1
Carregando...
Imagem de Miniatura
Nome:
license.txt
Tamanho:
2.12 KB
Formato:
Item-specific license agreed upon to submission
Descrição: