Lead-free Solder Joint Reliability – State of the Art and Perspectives

Pan, Jianbiao; Wang, Jyhwen; Shaddock, David

doi:10.4071/1551-4897-2.1.72

Cited by 18 publications

(6 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This result implies that the reliability of SnAgCu alloys outperform SnPb for small components and vice versa for large components. This conclusion is consistent with the thermal fatigue experimental results that suggested that SnAgCu alloys outperform SnPb at low strain applications and vice versa at high-strain amplitude applications [14][15][16][17][18][19]. Figure 10.…”

Section: Effect Of Thermal Shocksupporting

confidence: 81%

Investigation of the Lead-free Solder Joint Shear Performance

Webster

Pan

Toleno

2007

Journal of Microelectronics and Electronic Packaging

Self Cite

View full text Add to dashboard Cite

Reflow profile has significant impact on solder joint performance because it influences wetting and microstructure of the solder joint. The purpose of this study is to investigate the effects of reflow profile and thermal shock on the shear performance of eutectic SnPb (SnPb) and Sn3.0Ag0.5Cu (SAC305) solder joints. Test boards were assembled with four different sized surface mount chip resistors (1206, 0805, 0603 and 0402). Nine reflow profiles for SAC 305 and nine reflow profiles for SnPb were developed with three levels of peak temperature (12ºC, 22ºC, and 32ºC above solder liquidus temperature, or 230ºC, 240ºC, and 250ºC for SAC 305; and 195ºC, 205ºC, and 215ºC for SnPb) and three levels of time above solder liquidus temperature (30 sec., 60 sec., and 90 sec.). Half of the test vehicles were then subjected to air-to-air thermal shock conditioning from -40 to 125°C. The shear force data were analyzed using the Analysis of Variance (ANOVA). The fracture surfaces were studied using a Scanning Electron Microscopy (SEM) with Energy Dispersive Spectroscopy (EDS). It was found that thermal shock degraded both SnPb and SnAgCu joints shear strength, and that the effect of thermal shock on solder joint shear strength is much more significant than that of reflow profile. The SnAgCu solder joints have weaker shear strength than the SnPb solders. SnAgCu solder joint after thermal shock retains more of its shear strength than that of SnPb for small components and vice versa for larger components.

show abstract

Section: Effect Of Thermal Shocksupporting

confidence: 81%

Investigation of the Lead-free Solder Joint Shear Performance

Webster

Pan

Toleno

2007

Journal of Microelectronics and Electronic Packaging

Self Cite

View full text Add to dashboard Cite

show abstract

“…Therefore, in this study, DRL-coated donors were employed. The DRL was prepared by spin coating a Ag nanoparticle ink (SunChemicals, 20 wt.% silver content) onto the donor substrate (quartz window, 50 mm dia × 3mm thick purchased from UQG Optics) at 1000 rpm for 30 s. After the spin coating procedure, the Ag NP ink was dried at 75 °C for 10 min and then sintered at 175 °C for 10 min, resulting in a thin (300 nm thick) Ag layer [ 6 ]. Silver was chosen as the DRL material for compatibility reasons, considering that the solder paste already contains a small percentage of silver.…”

Section: Methodsmentioning

confidence: 99%

“…Conventional chip-bonding technologies spanning wire or thermosonic bonding and flip-chip bonding, have been improving in terms of throughput and reliability [1], but still cannot process flexible dies [2], nor accommodate the conformal attachment of dies on-chip with non-planar surface morphologies [3,4]. However, novel integration schemes and printable materials [5] have enabled innovative configurations, such as flexible and stretchable devices, aligned with environmental concerns for greener approaches [6]. These integration schemes, incorporating heterostructures and 3D architectures in many cases [7], have laid the foundations for a novel paradigm in interconnection technology: the digital and drop-on-demand fabrication techniques [8].…”

Section: Introductionmentioning

confidence: 99%

Eco-Friendly Lead-Free Solder Paste Printing via Laser-Induced Forward Transfer for the Assembly of Ultra-Fine Pitch Electronic Components

et al. 2021

View full text Add to dashboard Cite

Current challenges in printed circuit board (PCB) assembly require high-resolution deposition of ultra-fine pitch components (<0.3 mm and <60 μm respectively), high throughput and compatibility with flexible substrates, which are poorly met by the conventional deposition techniques (e.g., stencil printing). Laser-Induced Forward Transfer (LIFT) constitutes an excellent alternative for assembly of electronic components: it is fully compatible with lead-free soldering materials and offers high-resolution printing of solder paste bumps (<60 μm) and throughput (up to 10,000 pads/s). In this work, the laser-process conditions which allow control over the transfer of solder paste bumps and arrays, with form factors in line with the features of fine pitch PCBs, are investigated. The study of solder paste as a function of donor/receiver gap confirmed that controllable printing of bumps containing many microparticles is feasible for a gap < 100 μm from a donor layer thickness set at 100 and 150 μm. The transfer of solder bumps with resolution < 100 μm and solder micropatterns on different substrates, including PCB and silver pads, have been achieved. Finally, the successful operation of a LED interconnected to a pin connector bonded to a laser-printed solder micro-pattern was demonstrated.

show abstract

“…With the help of scanning acoustic microscopy (SAM) analysis we could rule out package internal delaminations of group TC2-C due to the higher board assembly reflow wetable area of thermal pad solder resist thermal via temperatures as potential reason for the worse behavior. Generally the relative ranking of the solder materials in an accelerated temperature cycling test depends on the strain level [7,8,13,14]. Our experiment indicates a relatively high strain level in the solder joints.…”

Section: Resultsmentioning

confidence: 91%

“…This relative ranking SnPbAg vs. SnAgCu is different to our temperature cycling results. This may be due to the fact that in power cycling the strain ranges are much smaller than in the temperature cycling test (because of the lower maximum temperature gradients) [13,14].…”

Section: Correlation Of Simulation With Experiments and Discussionmentioning

confidence: 99%

Reliability Investigations of Leadless QFN Packages until End-of-Life with Application Specific Board Level Stress Tests

Birzer

Stoeckl

Schuetz

et al.

56th Electronic Components and Technology Conference 2006

View full text Add to dashboard Cite

We report board level stress tests of leadless QFN packages (pitch 0.5 mm) with focus on different application fields. We did temperature cycling tests, drop test, bend test, and power cycling tests, with special focus on the influences of board design and soldering technology. We performed the stress tests until end-of-life and determined the dominating failure modes. In our temperature cycling study on 2.35 mm thick boards solder joints of SnAgCu performed slightly worse than SnPbAg. We were able to optimize the thermal pad design on the PCB to improve the temperature cycling reliability. For drop test we achieved an excellent reliability by comparing different board designs. This was achieved by avoiding copper trace cracking within the board. This failure mode we verified also with cyclic bend tests. Additionally we performed power cycling investigations using different power consumptions and solder pastes for board assembly (SnAgCu and SnPbAg). A strong lifetime dependence on power and a superior behavior of SnAgCu solder was found. The results were successfully correlated with finite element simulations. In our stress tests we observed clear evidence for influence of soldering technology and board design/technology on board level reliability performance. For different application fields satisfactory reliability can be achieved in case specific measures on board assembly and printed circuit board design are taken. IntroductionDuring the last years Quad Flat No-lead (QFN) packages became very popular as cost effective solution for low pincount IC products. A QFN is a plastic encapsulated package with a copper leadframe, which is exposed on the package bottom side. The peripheral leads as well as the exposed die pad can be soldered to the printed circuit board (PCB) by standard SMT processes. Figure 1 shows a schematic cross section of a QFN on a PCB.

show abstract

Lead-free Solder Joint Reliability – State of the Art and Perspectives

Cited by 18 publications

References 21 publications

Investigation of the Lead-free Solder Joint Shear Performance

Investigation of the Lead-free Solder Joint Shear Performance

Eco-Friendly Lead-Free Solder Paste Printing via Laser-Induced Forward Transfer for the Assembly of Ultra-Fine Pitch Electronic Components

Reliability Investigations of Leadless QFN Packages until End-of-Life with Application Specific Board Level Stress Tests

Contact Info

Product

Resources

About