A Study of Impact Reliability of Lead-free BGA Balls on Au/Electrolytic Ni/Cu Bond Pad

2005 ◽  
Vol 863 ◽  
Author(s):  
Shengquan Ou ◽  
Yuhuan Xu ◽  
K. N. Tu ◽  
M. O. Alam ◽  
Y. C. Chan
Keyword(s):  
Impact Toughness ◽  
Thermal Aging ◽  
Solder Joints ◽  
Lead Free ◽  
Impact Machine ◽  
Wire Bonds ◽  
Impact Reliability ◽  
Lead Free Solders ◽  
The Impact ◽  
Packaging Module

AbstractThe most frequent failure of wireless, handheld, and movable consumer electronic products is an accidental drop to the ground. The impact may cause interfacial fracture of wire-bonds or solder joints between a Si chip and its packaging module. Existing metrologies, such as ball shear, and pull test cannot well represent the shock reliability of the package. In this study, a micro-impact machine is utilized to test the impact reliability of three kinds of lead-free solders: 99Sn1Ag, 98.5Sn1Ag0.5Cu and 97.5Sn1Ag0.5Cu1In (hereafter called Sn1Ag, Sn1Ag0.5Cu, and Sn1Ag0.5Cu1In). The effect of thermal aging on the impact toughness is also evaluated in this study. We find a ductile-to-brittle transition in SnAg (Cu) solder joints after thermal aging. The impact toughness is enhanced by the thermal aging. This is a combination effect of the growth of intermetallic compound (IMC) at the interface provided strong bonding, and the softening of the solder bulk during the thermal aging absorbed more energy during plastic deformation.

Nanoindentation Characterization of Lead-free Solders and Intermetallic Compounds under Thermal Aging

2010 ◽  
Vol 2010 (1) ◽  
pp. 000314-000318
Author(s):  
Tong Jiang ◽  
Fubin Song ◽  
Chaoran Yang ◽  
S. W. Ricky Lee
Keyword(s):  
Mechanical Properties ◽  
Thermal Aging ◽  
Solder Joints ◽  
Lead Free ◽  
Small Range ◽  
Lead Free Solder ◽  
Solder Alloys ◽  
Aging Test ◽  
Free Solder ◽  
Lead Free Solders

The enforcement of environmental legislation is pushing electronic products to take lead-free solder alloys as the substitute of traditional lead-tin solder alloys. Applications of such alloys require a better understanding of their mechanical behaviors. The mechanical properties of the lead-free solders and IMC layers are affected by the thermal aging. The lead-free solder joints on the pads subject to thermal aging test lead to IMC growth and cause corresponding reliability concerns. In this paper, the mechanical properties of the lead-free solders and IMCs were characterized by nanoindentation. Both the Sn-rich phase and Ag3Sn + β-Sn phase in the lead-free solder joint exhibit strain rate depended and aging soften effect. When lead-free solder joints were subject to thermal aging, Young's modulus of the (Cu, Ni)6Sn5 IMC and Cu6Sn5 IMC changed in very small range. While the hardness value decreased with the increasing of the thermal aging time.

A Novel Mechanism of Embrittlement Affecting the Impact Reliability of Tin-Based Lead-Free Solder Joints

2009 ◽  
Vol 38 (9) ◽  
pp. 1881-1895 ◽  
Author(s):  
Konstantina Lambrinou ◽  
Wout Maurissen ◽  
Paresh Limaye ◽  
Bart Vandevelde ◽  
Bert Verlinden ◽  
...  
Keyword(s):  
Solder Joints ◽  
Lead Free ◽  
Lead Free Solder ◽  
Free Solder ◽  
Impact Reliability ◽  
The Impact

Interfacial reactions and impact reliability of Sn–Zn solder joints on Cu or electroless Au/Ni(P) bond-pads

2004 ◽  
Vol 19 (10) ◽  
pp. 2887-2896 ◽  
Author(s):  
M. Date ◽  
K.N. Tu ◽  
T. Shoji ◽  
M. Fujiyoshi ◽  
K. Sato
Keyword(s):  
Impact Toughness ◽  
Solder Joints ◽  
Void Formation ◽  
Charpy Impact ◽  
Charpy Impact Test ◽  
Joint Reliability ◽  
Solder Balls ◽  
Bond Interface ◽  
Impact Reliability ◽  
The Impact

Sn–9Zn and Sn–8Zn–3Bi solder balls were bonded to Cu or electroless Au/Ni(P)pads, and the effect of aging on joint reliability, including impact reliability, was investigated. For the purpose of quantitatively evaluating the impact toughness ofthe solder joints, a test similar to the classic Charpy impact test was performed.The interfacial compounds formed in the solder/Cu joint during soldering wereCu–Zn intermetallic compounds (IMCs), not Cu–Sn IMCs. One of the Cu–Zn IMCs, γ–Cu5Zn8, thickened remarkably with aging, and eventually its morphology changed from layer-type into discontinuous. The rapid growth of the γ–Cu5Zn8 and void formation at the bond interface led to the significant degradation of the joint reliability due to a ductile-to-brittle transition of the joint. Meanwhile, the compound formed in the solder/Au/Ni(P) joint during soldering was a Au–Zn IMC, above which Zn redeposited during aging. Both the dissolution and diffusion of Ni into the solders were extremely slow, which contributes to negligible void formation at the bond interface. As a result, the solder bumps on the Au/Ni(P) pads were able to maintain the high joint strength and impact toughness even after prolonged aging.

Effect of Aging on the Properties of Intermetallic Layers in SAC+Bi Solder Joints

2021 ◽  
Author(s):  
Mohammad Ashraful Haq ◽  
Mohd Aminul Hoque ◽  
Jeffrey C. Suhling ◽  
Pradeep Lall
Keyword(s):  
Solder Joints ◽  
Lead Free ◽  
Lead Free Solder ◽  
Aging Condition ◽  
Sac305 Solder ◽  
The Poor ◽  
Free Solder ◽  
Lead Free Solders ◽  
Overall Reliability ◽  
Intermetallic Layers

Abstract A major problem faced by electronic packaging industries is the poor reliability of lead free solder joints. One of the most common methods utilized to tackle this problem is by doping the alloy with other elements, especially bismuth. Researches have shown Bismuth doped solder joints to mostly fail near the Intermetallic (IMC) layer rather than the bulk of the solder joint as commonly observed in traditional SAC305 solder joints. An understanding of the properties of this IMC layer would thus provide better solutions on improving the reliability of bismuth doped solder joints. In this study, the authors have used three different lead free solders doped with 1%, 2% and 3% bismuth. Joints of these alloys were created on copper substrates. The joints were then polished to clearly expose the IMC layers. These joints were then aged at 125 °C for 0, 1, 2, 5 and 10 days. For each aging condition, the elastic modulus and the hardness of the IMC layers were evaluated using a nanoindenter. The IMC layer thickness and the chemical composition of the IMC layers were also determined for each alloy at every aging condition using Scanning Electron Microscopy (SEM) and EDS. The results from this study will give a better idea on how the percentage of bismuth content in lead free solder affects the IMC layer properties and the overall reliability of the solder joints.

Measurement of impact toughness of eutectic SnPb and SnAgCu solder joints in ball grid array by mini-impact tester

2008 ◽  
Vol 23 (5) ◽  
pp. 1482-1487 ◽  
Author(s):  
Yuhuan Xu ◽  
Shengquan Ou ◽  
K.N. Tu ◽  
Kejun Zeng ◽  
Rajiv Dunne
Keyword(s):  
Impact Toughness ◽  
High Speed ◽  
Solder Joints ◽  
Ball Grid Array ◽  
Snagcu Solder ◽  
Snpb Solder ◽  
Impact Tester ◽  
Pull Tests ◽  
The Impact ◽  
Eutectic Snpb

The most frequent cause of failure for wireless, handheld, and portable consumer electronic products is an accidental drop to the ground. The impact may cause interfacial fracture of ball-grid-array solder joints. Existing metrology, such as ball shear and ball pull tests, cannot characterize the impact-induced high speed fracture failure. In this study, a mini-impact tester was utilized to measure the impact toughness and to characterize the impact reliability of both eutectic SnPb and SnAgCu solder joints. The annealing effect at 150 °C on the impact toughness was investigated, and the fractured surfaces were examined. The impact toughness of SnAgCu solder joints with the plating of electroless Ni/immersion Au (ENIG) became worse after annealing, decreasing from 10 or 11 mJ to 7 mJ. On the other hand, an improvement of the impact toughness of eutectic SnPb solder joints with ENIG was recorded after annealing, increasing from 6 or 10 to 15 mJ. Annealing has softened the bulk SnPb solder so that more plastic deformation can occur to absorb the impact energy.

Impact Toughness of Titanium Alloys with Different Strengthening Methods

2007 ◽  
Vol 353-358 ◽  
pp. 433-437 ◽  
Author(s):  
Qiao Yan Sun ◽  
Lin Xiao ◽  
Jun Sun
Keyword(s):  
Low Temperature ◽  
Impact Toughness ◽  
Room Temperature ◽  
Alloying Elements ◽  
Initiation Energy ◽  
Impact Machine ◽  
Impact Tests ◽  
General Yielding ◽  
The Impact ◽  
Effect Of Alloying

In present paper effect of alloying elements and strengthening particle on the impact toughness were investigated. Load and energy in the impact tests were also discussed in detail for Ti-2Al, Ti-2Sn,Ti-2Zr, Ti-1Mo and Ti/TiC. Impact tests were carried out at room temperature (293K) and low temperature (83K) using a 300J capacity impact machine. Ti-1Mo, Ti-2Zr,Ti-2Sn alloys exhibit high impact toughness even at low temperature, while Ti-2Al and Ti/TiC only have high toughness at room temperature. At room temperature, general yielding occurred in all the materials, but it occurred only in Ti-1Mo, Ti-2Zr and Ti-2Sn at low temperature. It seemed that strengthening titanium couldn’t affect the elastic energy (Ei) effectively, but bring about more changes to Ep (propagation energy of crack) than to Ei (initiation energy of crack). As for the effect of alloying elements on the impact toughness, it seems to be related to the comprehensive result of the concentration and electronegative property of alloying elements. The interface between the TiC particles and matrix resulted in low toughness, especially at cryogenic temperature.

Examination of the impact test equipment used for the assessment of drop impact reliability for the solder joints

2002 ◽  
Vol 2002 (0) ◽  
pp. 239-240
Author(s):  
Qiang YU ◽  
Hironobu KIKUCHI ◽  
Keiji WATANABE ◽  
Manabu KAKINO ◽  
Noriyuki FUJIWARA ◽  
...  
Keyword(s):  
Impact Test ◽  
Solder Joints ◽  
Drop Impact ◽  
Test Equipment ◽  
Impact Reliability ◽  
The Impact
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