Characterization of SnAgCu and SnPb solder joints on low‐temperature co‐fired ceramic substrate

Zhong, Zhang; Arulvanan, P.; Maw, H. P.; Lu, Chuanhe

doi:10.1108/09540910710848518

Cited by 5 publications

(3 citation statements)

References 46 publications

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“…Volume 22 • Number 2 • 2010 • 21-29 in accordance with the average void content of less than 10 percent reported by Zhong et al (2007) in Sn3.5Ag0.7Cu solder joints between Ag-metallized pads of LTCC modules and ENIG-deposited silicon dies (pad size ϭ 1 mm ϫ 1 mm). On the other hand, the solderability of sintered metallization pads depends not only on the solder paste (composition of the alloy and flux system) and the soldering parameters, the quality of the metallization (pad) surface also has a major effect on solderability (Bochenek et al, 2001).…”

Section: Soldering and Surface Mount Technologysupporting

confidence: 79%

Thermomechanically loaded lead-free LGA joints in LTCC/PWB assemblies

Nousiainen

Urhonen

Kangasvieri

et al. 2010

SSMT

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Purpose -The purpose of this paper is to investigate the feasibility of using land grid array (LGA) solder joints as a second-level interconnection option in low-temperature co-fired ceramic (LTCC)/printed wiring board (PWB) assemblies for telecommunication applications. The characteristic behaviour of two commercial lead-free solder materials (Sn4Ag0.5Cu and Sn3Ag0.5Cu0.5In0.05Ni) in reflow processes and thermal cycling tests are also evaluated. Design/methodology/approach -The effect of the reflow temperature profile on voiding in two lead-free solders in LTCC/PWB assemblies was investigated using X-ray and scanning electron microscopy (SEM) investigations. The test assemblies were fabricated and exposed to a temperature cycling test (TCT) in a 0-100°C or Ϫ40 to 125°C temperature range. Organic PWB material with a low coefficient of thermal expansion (CTE) was primarily used. In addition, to compare LGA assemblies with low and high global thermal mismatches, an LTCC module/FR-4 assembly was also fabricated and exposed to a TCT in a 0-100°C temperature range. The characteristic lifetime of the test assemblies was determined using DC resistance measurements. The failure mechanisms of the interconnections were verified using scanning acoustic microscopy, SEM and finite element (FE)-SEM investigations. Findings -This work showed that the solderability of AgPt-metallized LTCC modules was poor, resulting in excessive voiding. This problem was avoided by using pre-tinned modules. In the test assemblies, the Sn4Ag0.5Cu joints had a lower void content and a higher characteristic lifetime compared with the Sn3Ag0.5Cu0.5In0.05Ni joints. Furthermore, it was observed that the Sn3Ag0.5Cu0.5In0.05Ni joints were more prone to fail along the interface between the Ag 3 Sn layer and the solder matrix than were the Sn4Ag0.5Cu joints. It was assumed that the observed difference in the primary failure mechanisms resulted in the decreased lifetime duration of the SnAgCu-InNi/Arlon in both temperature cycling conditions. Originality/value -The results proved that the solderability of both solders in AgPt-metallized modules in a typical surface mount technology process was poor; however, the solderability of the test modules can be notably enhanced with pre-tinned pads. This work also demonstrated the effect of the metallization/solder pair on the failure mechanisms and failure rate in LTCC/PWB assemblies with LGA joints; the work also proved in the TCT, over a temperature range of 0-100°C, that using the present LGA joints in LTCC/PWB assemblies with a high global thermal mismatch did not increase the lifetime duration of the joints to the preferred level (3,000 cycles), whereas the performance of these joints was adequate in assemblies with a low global thermal mismatch. Moreover, the results indicated that using the LGA joint configuration enhanced the reliability of the LTCC/PWB assemblies compared with similar assemblies with collapsible ball grid array solder spheres.

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Section: Soldering and Surface Mount Technologysupporting

confidence: 79%

Thermomechanically loaded lead-free LGA joints in LTCC/PWB assemblies

Nousiainen

Urhonen

Kangasvieri

et al. 2010

SSMT

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“…In most cases, co-fired Ag-based thick films are used as the solder lands on LTCC. Although it has been suggested recently that AgPd metallization may be used in lead-free 1st level interconnections between silicon chips and the LTCC substrate (Zhong et al, 2007), this metallization material is not feasible for 2nd level solder joints between the substrate and the organic motherboard due to its tendency to dissolve into molten solder (Fu and Huang, 2000;Rautioaho et al, 2001;Tian and Kutilainen, 2003;Nousiainen et al, 2005). This causes dispersion strengthening in the solder matrix, which, in turn, induces ceramic cracking in the thermomechanically loaded LTCC substrate (Fu and Huang, 2000;Rautioaho et al, 2001;Nousiainen et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Effect of ENIG deposition on the failure mechanisms of thermomechanically loaded lead‐free 2nd level interconnections in LTCC/PWB assemblies

Nousiainen

Kangasvieri

Kautio

et al. 2010

Soldering &Amp; Surface Mount Technology

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Purpose -The purpose of this paper is to investigate the effect of electroless NiAu (ENIG) deposition on the failure mechanisms and characteristic lifetimes of three different non-collapsible lead-free 2nd level interconnections in low-temperature co-fired ceramic (LTCC)/printed wiring board (PWB) assemblies. Design/methodology/approach -Five LTCC module/PWB assemblies were fabricated and exposed to a temperature cycling test over a 2 40 to 1258C temperature range. The characteristic lifetimes of these assemblies were determined using direct current resistance measurements. The failure mechanisms of the test assemblies were verified using X-ray and scanning acoustic microscopy, optical microscopy with polarized light, scanning electron microscope (SEM)/energy dispersive spectroscopy and field emission-SEM investigation. Findings -A stable intermetallic compound (IMC) layer is formed between the Ni deposit and solder matrix during reflow soldering. The layer thickness does not grow excessively and the interface between the layer and solder is practically free from Kirkendall voids after the thermal cycling test (TCT) over a temperature range of 2 40 to 1258C. The adhesion between the IMC layer and solder matrix is sufficient to prevent separation of this interface, resulting in intergranular (creep) or mixed transgranular/intergranular (fatigue/creep) failure within the solder matrix. However, the thermal fatigue endurance of the lead-free solder has a major effect on the characteristic lifetime, not the deposit material of the solder land. Depending on the thickness of the LTCC substrate and the composition of the lead-free solder alloy, characteristic lifetimes of over 2,000 cycles are achieved in the TCT. Originality/value -The paper investigates in detail the advantages and disadvantages of ENIG deposition in LTCC/PWB assemblies with a large global thermal mismatch (DCTE $ 10 ppm/8C), considering the design and manufacturing stages of the solder joint configuration and its performance under harsh accelerated test conditions.

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“…그 중에서 Sn-3.0Ag-0.5Cu 조성(SAC305)은 기존 유연솔더에 비해 34 o C 정도 융점이 높지만 젖음성(wettability), 기계적 강도, 접합 부 신뢰성 등이 양호하여 현재 무연 전자기기에서 가장 널리 사용되고 있다. [1][2][3] 최근 전자산업의 주력제품인 스마트폰, 태블릿 PC 등 모바일기기에도 SAC305 조성이 주로 사용되고 있는데, SAC305는 접합부 미세조직에 취성이 큰 Ag 3 Sn 상이 다 량 석출되어 기계적 충격에 대한 신뢰성이 취약한 것으 로 보고되고 있다. 4) SAC305 무연솔더에서 3.0 wt%의 Ag는 공정조성에 가 까운 합금을 형성하고 솔더 젖음성을 향상시키는 역할을 한다.…”

Section: 서 론unclassified

Solderability and BGA Joint Reliability of Sn-Ag-Cu-In-(Mn, Pd) Pb-free Solders

Jang¹,

Yu²,

Lee³

et al. 2013

Journal of the Microelectronics and Packaging Society

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초 록: Sn-3.0Ag-0.5Cu 무연솔더에서 Ag 함량의 감소는 기계적 충격 신뢰성 향상에 도움이 되는 반면 솔더링성을 저하시키는 것으로 알려져 있다. 본 연구에서는 저 Ag함유 무연솔더의 솔더링성 향상을 위해 In을 첨가한 Sn-1.2Ag-0.7Cu-0.4In 4원계 조성과 여기에 미량의 Mn 및 Pd을 첨가한 무연솔더 조성에 대하여 솔더 젖음성을 평가하고, 보드 레 벨 BGA 패키지의 열싸이클링 및 기계적 충격 신뢰성을 평가하였다. Sn-1.2Ag-0.7Cu 조성에 0.4 wt% In을 첨가한 합금 의 젖음성은 Sn-3.0Ag-0.5Cu에 근접한 수준으로 향상되었으나, 패키지의 열싸이클링 신뢰성은 Sn-3.0Ag-0.5Cu에 미치 지 못하는 것으로 나타났다. Sn-1.2Ag-0.7Cu-0.4In 조성에 0.03 wt% Pd의 첨가는 솔더 젖음성 및 패키지 신뢰성을 저하 시킨 반면에 0.1 wt% Mn을 첨가한 합금은 특히 기계적 충격 신뢰성이 Sn-3.0Ag-0.5Cu는 물론 Sn-1.0Ag-0.5Cu보다도 우수한 수준으로 향상되었는데, 이는 Mn 첨가가 합금의 모듈러스를 감소시킨 데에 기인하는 것으로 생각된다.

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Characterization of SnAgCu and SnPb solder joints on low‐temperature co‐fired ceramic substrate

Cited by 5 publications

References 46 publications

Thermomechanically loaded lead-free LGA joints in LTCC/PWB assemblies

Thermomechanically loaded lead-free LGA joints in LTCC/PWB assemblies

Effect of ENIG deposition on the failure mechanisms of thermomechanically loaded lead‐free 2nd level interconnections in LTCC/PWB assemblies

Solderability and BGA Joint Reliability of Sn-Ag-Cu-In-(Mn, Pd) Pb-free Solders

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