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

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.

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EFFECT OF BORON ON MICROSTRUCTURE AND MECHANICAL PROPERTIES OF HOT-ROLLED Nb-ADDED HSLA H-SECTION STEEL

International Journal of Modern Physics B ◽

10.1142/s0217979209061780 ◽

2009 ◽

Vol 23 (06n07) ◽

pp. 1885-1890 ◽

Cited By ~ 5

Author(s):

ZUOCHENG WANG ◽

GUOTAO CUI ◽

TAO SUN ◽

WEIMIN GUO ◽

XIULING ZHAO ◽

...

Keyword(s):

Mechanical Properties ◽

Impact Toughness ◽

Charpy Impact ◽

High Strength ◽

Charpy Impact Test ◽

Uniaxial Tensile ◽

Uniaxial Tensile Test ◽

Boron Addition ◽

Low Temperature Impact Toughness ◽

The Impact

In our research, boron was added into the Nb -added high strength low alloy (HSLA) H -section steels. The contents of boron added were 4ppm, 8ppm and 11ppm, respectively. The mechanical properties of H -section steels with/without boron were examined by using uniaxial tensile test and Charpy impact test ( V -notch). The morphologies of the microstructure and the fracture surfaces of the impact specimens were observed by metalloscope, stereomicroscope and electron probe. The experimental results indicate that boron gives a significant increase in impact toughness, especially in low temperature impact toughness, though it leads to an unremarkable increase in strength and plasticity. For instance, the absorbed energy at -40°C reaches up to 126J from 15J by 8ppm boron addition, and the ductile-brittle transition temperature declines by 20°C. It is shown that boron has a beneficial effect on grain refinement. The fracture mechanism is transited from cleavage fracture to dimple fracture due to boron addition.

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Effect of Shock Temperature on the Impact Toughness of Butt-Joint

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.602-604.2096 ◽

2012 ◽

Vol 602-604 ◽

pp. 2096-2099

Author(s):

Min You ◽

Ling Wu ◽

Hai Zhou Yu ◽

Jing Rong Hu ◽

Mei Li

Keyword(s):

Impact Toughness ◽

Impact Test ◽

Charpy Impact ◽

Charpy Impact Test ◽

Butt Joint ◽

Adhesively Bonded ◽

A Value ◽

Shock Temperature ◽

Izod Impact ◽

The Impact

The effect of the shock temperature and time on the impact toughness of the adhesively bonded steel butt joint under Charpy or Izod impact test is studied using the experimental method. The results obtained show that the impact toughness decreases when the shock temperature increased. When the curing time, temperature as well as the open assembly time was set as constant, the higher the shock temperature is, the lower the impact toughness of the joint. Comparing to the Charpy impact test, the Izod impact test is more sensitive to the shock temperature. When the shock temperature is set at a value not less than 300 C, the impact toughness measured is nearly the same as zero due to decomposition, carbonization and volatilization of the adhesive.

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Comparison of Impact Toughness and Fracture Morphologies Between Pb-Containing and Pb-Free Solder Joints Subject to the Charpy Impact Test

Journal of Electronic Materials ◽

10.1007/s11664-008-0551-z ◽

2008 ◽

Vol 37 (11) ◽

pp. 1756-1756 ◽

Cited By ~ 1

Author(s):

Ning Zhang ◽

Yaowu Shi ◽

Zhidong Xia ◽

Yongping Lei ◽

Fu Guo ◽

...

Keyword(s):

Impact Toughness ◽

Impact Test ◽

Solder Joints ◽

Charpy Impact ◽

Charpy Impact Test ◽

Free Solder ◽

Fracture Morphologies

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Effect of Trace Boron on Low Temperature Impact Toughness of Hot-Rolled Nb-Added HSLA H-Beams

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.174-177.1030 ◽

2012 ◽

Vol 174-177 ◽

pp. 1030-1033 ◽

Cited By ~ 1

Author(s):

Guo Tao Cui ◽

Zuo Cheng Wang ◽

Tao Sun ◽

Wei Min Guo ◽

Jun Qing Gao

Keyword(s):

Impact Toughness ◽

Impact Energy ◽

Charpy Impact ◽

Charpy Impact Test ◽

Total Oxygen ◽

Transmission Electron ◽

Temperature Impact ◽

Low Temperature Impact Toughness ◽

Hot Rolled ◽

The Impact

In this research, trace boron (4ppm, 8ppm, 11ppm) was added into the Nb-added HSLA H-beams. The impact toughness of H-beams with/without boron was examined by Charpy impact test (V-notch). The morphologies of the microstructure and the fracture surfaces of the impact specimens were observed by metalloscope, stereomicroscope and electron probe. The experimental results prove that the absorbed impact energy at -40°C for the 4ppm, 8ppm, 11ppm boron-added steels respectively reaches up to 80J, 126J, 85J from 15J and H-beams with boron have a lower FATT than that without boron. It is also found that the total oxygen content affects the absorbed impact energy to a certain extent. It is discovered by transmission electron microscope (TEM) that boron mainly exists in solid solution state, except that a little amount of Fe23(C, B)6is formed at the grain boundaries, and the distribution of Nb(C, N) is also influenced by boron addition.

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

MRS Proceedings ◽

10.1557/proc-863-b10.5 ◽

2005 ◽

Vol 863 ◽

Cited By ~ 4

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.

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Comparison of Impact Toughness and Fracture Morphologies Between Pb-Containing and Pb-Free Solder Joints Subject to the Charpy Impact Test

Journal of Electronic Materials ◽

10.1007/s11664-008-0506-4 ◽

2008 ◽

Vol 37 (10) ◽

pp. 1631-1639 ◽

Cited By ~ 15

Author(s):

Ning Zhang ◽

Yaowu Shi ◽

Zhidong Xia ◽

Yongping Lei ◽

Fu Guo ◽

...

Keyword(s):

Impact Toughness ◽

Impact Test ◽

Solder Joints ◽

Charpy Impact ◽

Charpy Impact Test ◽

Free Solder ◽

Fracture Morphologies

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Comparative analysis of dynamic strength and impact toughness of pipe steels

EPJ Web of Conferences ◽

10.1051/epjconf/202125004002 ◽

2021 ◽

Vol 250 ◽

pp. 04002

Author(s):

Anatoly Bragov ◽

Alexander Konstantinov ◽

Andrey Lomunov ◽

Leopold Kruszka

Keyword(s):

Impact Toughness ◽

Dynamic Strength ◽

Charpy Impact ◽

Original System ◽

Charpy Impact Test ◽

Load Cycle ◽

Pipe Steels ◽

Type Specimens ◽

Steel Grades ◽

The Impact

To study the dynamic strength of pipe steels, a cycle of dynamic tests of three grades of pipeline steels (X80, X90, and X100) was performed, which included three types of experiments based on the Kolsky method: uniaxial tension of smooth specimens, as well as tension of specimens with a V-shaped annular notch and Charpy impact test according to the three-point bending pattern of beam-type specimens with a V-notch. In the last two cases, the fracture force and impact toughness, as well as the nominal fracture stress in the specimen, were determined. To assess the effect of “cold brittleness” and determine the temperature of the ductile-brittle transition, the specified test cycle was carried out in the temperature range from +20°C to –100°C. As shown by the test results, the studied steels have a fairly high ductility: the elongation at break is 25-30%. Therefore, the destruction of specimens directly in the first load cycle is not always possible. The use of an original system for registering additional loading cycles makes it possible to determine in which loading cycle the specimen ruptured. The limiting characteristics of plasticity (ψ and δ) of all tested steel grades are weakly dependent on both the strain rate and temperature (within the range of their variation). Whereas the impact toughness of steels significantly (2-3 times) decreases with a decrease in temperatures from room temperature to –100°C.

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Effects of Al, Si and N Content on the Formation of M-A Constituent and HAZ Toughness of Ti-Containing Low-Carbon Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1016.42 ◽

2021 ◽

Vol 1016 ◽

pp. 42-49

Author(s):

Kook Soo Bang ◽

Joo Hyeon Cha ◽

Kyu Tae Han ◽

Hong Chul Jeong

Keyword(s):

Carbon Steel ◽

Impact Toughness ◽

Low Carbon Steel ◽

Charpy Impact ◽

Coarse Grained ◽

Low Carbon ◽

N Content ◽

Si Content ◽

The Impact ◽

Haz Toughness

The present work investigated the effects of Al, Si, and N content on the impact toughness of the coarse-grained heat-affected zone (CGHAZ) of Ti-containing low-carbon steel. Simulated CGHAZ of differing Al, Si, and N contents were prepared, and Charpy impact toughness was determined. The results were interpreted in terms of microstructure, especially martensite-austenite (M-A) constituent. All elements accelerated ferrite transformation in CGHAZ but at the same time increased the amount of M-A constituent, thereby deteriorating CGHAZ toughness. It is believed that Al, Si, and free N that is uncombined with Ti retard the decomposition of austenite into pearlite and increase the carbon content in the last transforming austenite, thus increasing the amount of M-A constituent. Regardless of the amount of ferrite in CGHAZ, its toughness decreased linearly with an increase of M-A constituent in this experiment, indicating that HAZ toughness is predominantly affected by the presence of M-A constituent. When a comparison of the effectiveness is made between Al and Si, it showed that a decrease in Si content is more effective in reducing M-A constituents.

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Suppression of Kirkendall voiding in Sn-3.5Ag/Cu solder joints by pre-annealing process

International Symposium on Microelectronics ◽

10.4071/isom-2011-tp4-paper3 ◽

2011 ◽

Vol 2011 (1) ◽

pp. 000337-000340

Author(s):

S. H. Kim ◽

Jin Yu

Keyword(s):

Solder Joints ◽

Void Formation ◽

Annealing Process ◽

Schematic Diagram ◽

Cu Films ◽

Joint Reliability ◽

Organic Impurities ◽

Solder Reflow ◽

Kirkendall Voids ◽

Annealing Method

In this study, electroplated Cu films were pre-annealed at T (T = 673, 773, 873 K) for varying times. Sn-3.5Ag solder reflowed over the Cu films and subsequently aged at 150°C for 240 hrs. Effects of pre-annealing on the microstructure of Cu films, as well as contents of organic impurities incorporated in the Cu films were investigated. After solder reflow, the formation of Kirkendall voids at Cu3Sn/Cu interface was observed from SEM micrographs. Results show that the pre-annealing process significantly suppressed Kirkendall void formation in the Sn-3.5Ag/Cu solder joints. A line fraction of voids at the Cu3Sn/Cu interface was definitely suppressed in the case of 500°C and 600°C pre-annealed samples compared to as-deposited Cu sample. SIMS analyses revealed that pre-annealing reduced the level of impurities in the Cu films, especially S and C. The mechanism of suppressing Kirkendall voids at the Cu3Sn/Cu interface was presented by schematic diagram, and it could be seen that pre-annealing method has a potential to enhance solder joint reliability.

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