Achieving high reliability low cost lead-free SAC solder joints via Mn or Ce doping

Liu, Weiping; Lee, Ning-Cheng; Porras, Adriana; Ding, Min; Gallagher, Tony; Huang, Austin; Chen, Scott; Lee, Jeffrey ChangBing

doi:10.1109/ectc.2009.5074134

Cited by 32 publications

(20 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Again, this can be attributed to the dilution effect of bump alloy by paste alloy. It is interesting to compare this data with the results of an earlier study on SAC105M [5]. In that work, the BGAs were assembled with SAC305 paste, and the TCT (-40 C/125 C) performance for devices which were pre-conditioned at 150 C/250 hrs are summarized in Table 5.…”

Section: Reliabilitymentioning

confidence: 96%

Shock resistant and thermally reliable low Ag SAC solder doped with Mn

Goudarzi¹,

Brown

Liu³

et al. 2013

2013 14th International Conference on Electronic Packaging Technology

Self Cite

View full text Add to dashboard Cite

98.5Sn0.5Ag1Cu0.05Mn (SAC0510M) exhibits a melting behavior similar to SAC105. It is two times better than SAC105 in the dynamic bending test; more than 8 times better in the modified JEDEC drop test; and more than 40-60% better in the -55 C/125 C thermal cycling test. The reduced hardness and much thinner and stable IMC layer on Ni are responsible for the superior nonfragility, while the stabilized IMC and microstructure are responsible for the thermal cycling performance. A thinner IMC layer on Ni is more important than reduced hardness in improving non-fragility. The thermal cycling performance of SAC0510M may override SAC305. A high Tg brittle board causes poor drop test results due to pad cratering. INTRODUCTIONLead-free soldering has been widely adopted by the electronics industry, with SnAgCu (SAC) having high Ag content being the initial main stream of choice. This selection was later challenged due to the fragility of solder joints toward drop and the high cost of Ag. Low Ag SAC was considered to be a solution for resolving both issues. However, this approach compromised temperature cycling performance, making it unacceptable for high end applications. Previously, a low Ag SAC alloy doped with Mn, SACM™, was reported to have considerable improvement in shock resistance and thermal fatigue performance. In this study, a second generation alloy within the SACM family was developed with significantly more improvement. It was evaluated against SAC105 for JEDEC22B111 drop, dynamic bending test, and IPC-9701 -55/125 C temperature cycling. The improvement essentially eliminated the need for underfilling for BGA and CSP on mobile devices, and the results are presented and discussed.

show abstract

Section: Reliabilitymentioning

confidence: 96%

Shock resistant and thermally reliable low Ag SAC solder doped with Mn

Goudarzi¹,

Brown

Liu³

et al. 2013

2013 14th International Conference on Electronic Packaging Technology

Self Cite

View full text Add to dashboard Cite

show abstract

“…Moreover, decreasing Ag content also reduces the cost of raw materials. However, this improvement in drop impact performance can occur with a worsening of temperature cycling reliability (Kittidacha et al, 2008;Syed et al, 2008;Shnawah et al, 2012a, b (Pandher and Healey, 2003;Liu et al, 2009;Yu et al, 2010;Shnawah et al, 2012a, b). The net result of a minor alloying addition is to:…”

Section: Introductionmentioning

confidence: 93%

The bulk alloy microstructure and tensile properties of Sn‐1Ag‐0.5Cu‐xAl lead‐free solder alloys (x=0, 1, 1.5 and 2 wt.%)

Shnawah

Sabri

Badruddin

et al. 2012

Microelectronics International

View full text Add to dashboard Cite

Purpose -The purpose of this paper is to investigate the effect of Al addition on the bulk alloy microstructure and tensile properties of the low Ag-content Sn-1Ag-0.5Cu (SAC105) solder alloy. Design/methodology/approach -The Sn-1Ag-0.5Cu-xAl (x ¼ 0, 1, 1.5 and 2 wt.%) bulk solder specimens with flat dog-bone shape were used for tensile testing in this work. The specimens were prepared by melting purity ingots of Sn, Ag, Cu and Al in an induction furnace. Subsequently, the molten alloys were poured into pre-heated stainless steel molds, and the molds were naturally air-cooled to room temperature. Finally, the molds were disassembled, and the dog-bone samples were removed. The solder specimens were subjected to tensile testing on an INSTRON tester with loading rate 10 2 3 s 2 1 . The microstructural analysis was carried out using scanning electron microscopy/Energy dispersive X-ray spectroscopy. Electron Backscatter Diffraction (EBSD) analysis was used to identify the IMC phases. To obtain the microstructure, the solder samples were prepared by dicing, molding, grinding and polishing processes.Findings -The addition of Al to the SAC105 solder alloy suppresses the formation of Ag 3 Sn and Cu 6 Sn 5 IMC particles and leads to the formation of larger Al-rich and Al-Cu IMC particles and a large amount of fine Al-Ag IMC particles. The addition of Al also leads to refining of the primary b-Sn grains. The addition of Al results in a significant increase on the elastic modulus and yield strength. On the other hand, the addition of Al drastically deteriorates the total elongation. Originality/value -The addition of Al to the low Ag-content SAC105 solder alloy has been discussed for the first time. This work provides a starting-point to study the effect of Al addition on the drop impact and thermal cycling reliability of the SAC105 alloy.

show abstract

“…7b, d). Mn added in the IMC layer degraded the brittleness of IMC structure [12], which enhanced the breaking strength of SnAgCuMn/Cu joint by aging. Besides, a large number of voids were detected in SnAgCu1.0Mn/Cu and SnAgCu1.5Mn/Cu joints after aged for 500 h at 150°C.…”

Section: Hardness and Tensile Properties Analysismentioning

confidence: 99%

“…Liu et al [5,12] reported that the Mn/Ce doped Sn1.0Ag0.5Cu alloys achieved a homogeneous microstructure, high strength in drop tests and high reliability in dynamic bending tests. The Sn1.0Ag0.5Cu ?…”

Section: Introductionmentioning

confidence: 99%

The effects of Mn powder additions on the microstructures and tensile property of SnAgCu/Cu solder joints

Shen

Zhang

et al. 2014

J Mater Sci: Mater Electron

View full text Add to dashboard Cite

In this paper, the effects of Mn powder on fusion property of Sn3.0Ag0.5Cu solder alloy and microstructures as well as tensile property of the solder joints of Sn3.0Ag0.5Cu/Cu were investigated by differential scanning calorimetry analysis, scanning electron microscopy and tensile tests. The results showed that the addition of Mn dramatically suppressed under cooling of SnAgCu solder alloy. Mn addition contributed to the growth of Cu 6 Sn 5 intermetallic compound layers since it provided nucleation sites for Cu 6 Sn 5 at the solder joints. Moreover, Mn addition increased the hardness of the solder alloys and reduced the tensile strength of SnAgCu/Cu solder joints. During aging, the growth of IMC layers of SnAgCuMn/Cu solder joints was slower than that of SnAgCu/Cu solder joints, and the tensile strength of all the solder joints increased after aging.

show abstract

Achieving high reliability low cost lead-free SAC solder joints via Mn or Ce doping

Cited by 32 publications

References 7 publications

Shock resistant and thermally reliable low Ag SAC solder doped with Mn

Shock resistant and thermally reliable low Ag SAC solder doped with Mn

The bulk alloy microstructure and tensile properties of Sn‐1Ag‐0.5Cu‐xAl lead‐free solder alloys (x=0, 1, 1.5 and 2 wt.%)

The effects of Mn powder additions on the microstructures and tensile property of SnAgCu/Cu solder joints

Contact Info

Product

Resources

About