Microstructures in solder joints between Sn95.5Ag4Cu0.5 solder and Ag/Pd thick film

Tian, Dewei; Kutilainen, Terho

doi:10.1007/s11664-003-0186-z

Cited by 4 publications

(3 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…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

View full text Add to dashboard Cite

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.

show abstract

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

View full text Add to dashboard Cite

show abstract

“…Since, the detrimental effect of an excessive amount of intermetallic compounds (IMCs) on the reliability of ceramic component/PWB assemblies is well-known, several studies have focused on either the reactions between liquid solder and Agbased (AgPd, and AgPdPt, AgPt) metallizations of ceramic substrates or solid state IMC layer growth in these metallization/ solder pairs during isothermal aging (Yamada et al, 1992;Shangguan et al, 1994;Tian and Kutilainen, 2003). Furthermore, shear stress tests and/or thermal cycling tests of The current issue and full text archive of this journal is available at www.emeraldinsight.com/0954-0911.htm The authors would like to acknowledge Mr L. Lehtiniemi, Mr T. Urhonen, and Mr J. Jääskeläinen for their assistance during the experimental work of this study.…”

Section: Introductionmentioning

confidence: 99%

Interfacial reactions between Sn‐based solders and AgPt thick film metallizations on LTCC

Nousiainen

Kangasvieri

Rönkä

et al. 2007

Soldering &Amp; Surface Mount Technology

View full text Add to dashboard Cite

Purpose -This paper aims to investigate the metallurgical reactions between two commercial AgPt thick films used as a solder land on a low temperature co-fired ceramic (LTCC) module and solder materials (SnAgCu, SnInAgCu, and SnPbAg) in typical reflow conditions and to clarify the effect of excessive intermetallic compound (IMC) formation on the reliability of LTCC/printed wiring boards (PWB) assemblies. Design/methodology/approach -Metallurgical reactions between liquid solders and AgPt metallizations of LTCC modules were investigated by increasing the number of reflow cycles with different peak temperatures. The microstructures of AgPt metallization/solder interfaces were analyzed using SEM/EDS investigation. In addition, a test LTCC module/PWB assembly with an excess IMC layer within the joints was fabricated and exposed to a temperature cycling test in a 2 40 to 1258C temperature range. The characteristic lifetime of the test assembly was determined using DC resistance measurements. The failure mechanism of the test assembly was verified using scanning acoustic microscopy and SEM investigation. Findings -The results showed that the higher peak reflow temperature of common lead-free solders had a significant effect on the consumption of the original AgPt metallization of LTCC modules. The results also suggested that the excess porosity of the metallization accelerated the degradation of the metallization layer. Finally, the impact of these adverse metallurgical effects on the actual failure mechanism in an LTCC/PWB assembly was demonstrated. Originality/value -This paper proves how essential it is to know the actual LTCC metallization/solder interactions that occur during reflow soldering and to recognize their effect on solder joint reliability in LTCC module/PWB assemblies. Moreover, the adverse effect of using lead-free solders on the degradation of Ag-based metallizations and, consequently, on board level reliability is demonstrated. Finally, practical guidelines for selecting materials for second-level solder interconnections of LTCC module are given.

show abstract

“…[1][2][3] However, the solidification characteristics and microstructure and mechanical properties of these alloys are quite different from traditional SnPb solder alloys. [4][5][6][7][8][9] The cooling rate in the reflow process has been found to have a significant effect on the microstructure of SAC alloys during solidification, 9,10 although creep behavior was not strongly dependent on the microstructure formation. 10 In the present research, test vehicles were assembled with the SAC solder alloy using three different cooling rates (normal, medium, and high) during the reflow process.…”

Section: Introductionmentioning

confidence: 99%

Accelerated thermal fatigue of lead-free solder joints as a function of reflow cooling rate

Yan

Zbrzezny

Agia³

et al. 2004

Journal of Elec Materi

View full text Add to dashboard Cite

Leadless chip resistor (LCR) assemblies were manufactured using both traditional tin-lead (Sn37Pb) and lead-free (Sn3.8Ag0.7Cu) solders. The leadfree test vehicles were assembled using three different cooling rates: 1.6°C/sec, 3.8°C/sec, and 6.8°C/sec. They were then exposed to accelerated thermalcycling (ATC) tests between 0°C and 100°C with a 10-14°C/min ramp rate and a 5-min dwell time. The test results indicated that these lead-free solder joints had better creep-fatigue performance than the tin-lead solder joints. The LCR built with the medium cooling rate showed the longest fatigue life compared with the resistors built with the normal cooling rate of 1.6°C/sec and the higher cooling rate 6.8°C/sec. The number of cycles to failure was significantly correlated to the void defect rate. Failure analyses were done using crosssectioning methods and scanning electron microscopy (SEM). Finite-element models were built to analyze the inelastic, equivalent strain range in solder joints subjected to thermal-cycling conditions with different degrees of solder wetting. The results indicated that poor wetting increases strains throughout the joint significantly, which is in accordance with the ATC results.

show abstract

Microstructures in solder joints between Sn95.5Ag4Cu0.5 solder and Ag/Pd thick film

Cited by 4 publications

References 17 publications

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

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

Interfacial reactions between Sn‐based solders and AgPt thick film metallizations on LTCC

Accelerated thermal fatigue of lead-free solder joints as a function of reflow cooling rate

Contact Info

Product

Resources

About