Shear Strength and Fracture Surface Studies of Ball Grid Array (BGA) Flexible Surface-Mount Electronics Packaging Under Isothermal Ageing

This paper elucidates the effect of isothermal ageing at temperature of 85 °C, 125 °C and 150 °C for 100, 500 and 1000 h on Sn-3.0Ag-0.5Cu (SAC305) lead-free solder with the addition of 1 wt% kaolin geopolymer ceramic (KGC) reinforcement particles. SAC305-KGC composite solders were fabricated through powder metallurgy using a hybrid microwave sintering method and reflowed on copper substrate printed circuit board with an organic solderability preservative surface finish. The results revealed that, the addition of KGC was beneficial in improving the total thickness of interfacial intermetallic compound (IMC) layer. At higher isothermal ageing of 150 °C and 1000 h, the IMC layer in SAC305-KGC composite solder was towards a planar-type morphology. Moreover, the growth of total interfacial IMC layer and Cu3Sn layer during isothermal ageing was found to be controlled by bulk diffusion and grain-boundary process, respectively. The activation energy possessed by SAC305-KGC composite solder for total interfacial IMC layer and Cu3Sn IMC was 74 kJ/mol and 104 kJ/mol, respectively. Based on a lap shear test, the shear strength of SAC305-KGC composite solder exhibited higher shear strength than non-reinforced SAC305 solder. Meanwhile, the solder joints failure mode after shear testing was a combination of brittle and ductile modes at higher ageing temperature and time for SAC305-KGC composite solder.

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Effect of intermetallic compound layer thickness on the shear strength of 1206 chip resistor solder joint

Soldering & Surface Mount Technology ◽

10.1108/ssmt-07-2013-0019 ◽

2015 ◽

Vol 27 (1) ◽

pp. 52-58 ◽

Cited By ~ 5

Author(s):

Peter K. Bernasko ◽

Sabuj Mallik ◽

G. Takyi

Keyword(s):

Shear Strength ◽

Intermetallic Compound ◽

Solder Joint ◽

Layer Thickness ◽

Solder Joints ◽

Ageing Time ◽

Circuit Board ◽

Intermetallic Compound Layer ◽

Content Type ◽

Surface Mount

Purpose – The purpose of this paper is to study the effect of intermetallic compound (IMC) layer thickness on the shear strength of surface-mount component 1206 chip resistor solder joints. Design/methodology/approach – To evaluate the shear strength and IMC thickness of the 1206 chip resistor solder joints, the test vehicles were conventionally reflowed for 480 seconds at a peak temperature of 240°C at different isothermal ageing times of 100, 200 and 300 hours. A cross-sectional study was conducted on the reflowed and aged 1206 chip resistor solder joints. The shear strength of the solder joints aged at 100, 200 and 300 hours was measured using a shear tester (Dage-4000PXY bond tester). Findings – It was found that the growth of IMC layer thickness increases as the ageing time increases at a constant temperature of 175°C, which resulted in a reduction of solder joint strength due to its brittle nature. It was also found that the shear strength of the reflowed 1206 chip resistor solder joint was higher than the aged joints. Moreover, it was revealed that the shear strength of the 1206 resistor solder joints aged at 100, 200 and 300 hours was influenced by the ageing reaction times. The results also indicate that an increase in ageing time and temperature does not have much influence on the formation and growth of Kirkendall voids. Research limitations/implications – A proper correlation between shear strength and fracture mode is required. Practical implications – The IMC thickness can be used to predict the shear strength of the component/printed circuit board pad solder joint. Originality/value – The shear strength of the 1206 chip resistor solder joint is a function of ageing time and temperature (°C). Therefore, it is vital to consider the shear strength of the surface-mount chip component in high-temperature electronics.

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A Novel Anisotropic Conductive Adhesive for Lead-Free Surface Mount Electronics Packaging

Electronic and Photonic Packaging, Electrical Systems Design and Photonics, and Nanotechnology ◽

10.1115/imece2005-83021 ◽

2005 ◽

Cited By ~ 3

Author(s):

S. Manian Ramkumar ◽

Krishnaswami Srihari

Keyword(s):

Surface Area ◽

Electronics Packaging ◽

Conductive Adhesive ◽

Lead Free ◽

The Novel ◽

Small Surface ◽

Surface Mount ◽

Anisotropic Conductive Adhesive ◽

Fine Pitch ◽

Very High

The electronics industry, in recent years, has been focusing primarily on product miniaturization and lead-free assembly. The need for product miniaturization is due to the continuous demand for portable electronic products that are multifunctional, yet smaller, faster, cheaper, and lighter. This is forcing the industry to design and assemble products with miniature passive and active devices. These devices typically have fine pitch footprints that provide a very small surface area for attachment. The solder attach technique relies primarily on the formation of intermetallics between the mating metallic surfaces. With a reduction in the surface area of the pads, the ratio of intermetallic to solder is very high once the solder joint is formed. This could result in unreliable solder joints, due to the brittle nature of intermetallics. In addition, the need to eliminate lead-based materials as a means of interconnection has renewed the industry’s interest in exploring other means of assembling surface mount devices reliably. This paper discusses the performance characteristics and preliminary research findings pertaining to a novel Anisotropic Conductive Adhesive (ACA) for electronics packaging applications, utilizing the Z Bond™ technology from Nexaura Systems, LLC. Typically, ACAs require the application of pressure during the curing process, to establish the electrical connection. The novel ACA uses a magnetic field to align the particles in the Z-axis direction and eliminates the need for pressure during curing. The formation of conductive columns within the polymer matrix provides a very high insulation resistance between adjacent conductors. The novel ACA also enables mass curing of the adhesive, eliminating the need for sequential assembly. The novel ACA’s I-V characteristics and performance under thermal and temperature-humidity aging are discussed in detail.

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Broad Bandwidth Study of the Topography of the Fracture Surface of Energetic Materials

MRS Proceedings ◽

10.1557/proc-140-411 ◽

1988 ◽

Vol 140 ◽

Author(s):

M. Yvonne D. Lanzerotti ◽

James J. Pinto ◽

Allan Wolfe

Keyword(s):

Shear Strength ◽

Fracture Surface ◽

Energetic Materials ◽

Power Spectra ◽

Low Frequency ◽

Frequency Region ◽

Fast Fourier Transform Algorithm ◽

Prolate Spheroidal ◽

Broad Bandwidth ◽

Fracture Surfaces

AbstractThe Z,X coordinates of the fracture surfaces of TNT have been measured witha stylus profilometer. The fracture surfaces of the material under study are obtained by accelerating prepared samples in anultracentrifuge. When the tensile or shear strength is exceeded a fracture surface is obtained. Usingdiamond and sapphire styli the topography of the fracture surface has been studied from a wavelength of 1.0 micron to nearly 1.0 centimeter. The powerspectra have been calculated from the data using a prolate spheroidal data window in the horizontal space domain prior to the employment of the fast Fourier transform algorithm. The power spectra are found to decrease with increasing spatial frequency. Peaks are observed in the low frequency region of the power spectra and indicate that much of the fracture is occurring atgrain boundaries.

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Determining the strength of brittle materials by means of fracture-surface studies

Strength of Materials ◽

10.1007/bf01522651 ◽

1975 ◽

Vol 7 (7) ◽

pp. 793-797 ◽

Cited By ~ 1

Author(s):

G. S. Pisarenko ◽

Yu. I. Kozub ◽

V. G. Soluyanov ◽

A. P. Poleshko

Keyword(s):

Fracture Surface ◽

Brittle Materials ◽

Surface Studies

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Microstructure evolution and mechanical properties of 5083 aluminum alloy joints by ultrasonic soldering

International Journal of Modern Physics B ◽

10.1142/s0217979217440404 ◽

2017 ◽

Vol 31 (16-19) ◽

pp. 1744040

Author(s):

Dengquan Han ◽

Yuanxing Li ◽

Yongpan He ◽

Sifu Qiu ◽

Hui Chen

Keyword(s):

Shear Strength ◽

Aluminum Alloy ◽

Fracture Surface ◽

Filler Metal ◽

Aluminum Alloy 5083 ◽

Zn Content ◽

Ultrasonic Soldering ◽

5083 Aluminum Alloy ◽

Pure Sn ◽

Shear Strength Reduction

Aluminum alloy 5083 was joined with Sn–[Formula: see text]Zn ([Formula: see text], 5, 9, 30 and 60 wt.%) filler metal by ultrasonic soldering at 400[Formula: see text]C. The joint microstructure consisted of [Formula: see text]-Sn and [Formula: see text]-Al solid–solution phases when using pure Sn solder. Zn-rich phases were observed in the joints with Sn–Zn filler metal. The Zn-rich phases grew thicker and larger with the increase in Zn content in the filler metal. The joints soldered with Sn–30Zn filler metal reached a maximum shear strength of 70 MPa. Joint cracking occurred at the interface of pure Sn and Sn–9Zn solders as indicated by SEM observation of the fracture surfaces. The locations of the fracture surface moved from the interface to the seam when using the Sn–30Zn or Sn–60Zn filler metal. The coarse Zn-rich phases were also observed on the fracture surface using Sn–60Sn solder, which results in a shear strength reduction of the joints.

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SURFACE-MOUNT PIFA USING BALL GRID ARRAY PACKAGING FOR 5G MMWAVE

Progress In Electromagnetics Research Letters ◽

10.2528/pierl21050203 ◽

2021 ◽

Vol 98 ◽

pp. 55-60

Author(s):

Xi Wang ◽

Xiubo Liu ◽

Wei Zhang ◽

Dongning Hao ◽

Yanyan Liu

Keyword(s):

Ball Grid Array ◽

Surface Mount

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Urea Formaldehyde Resin Resultant Plywood with Rapid Formaldehyde Release Modified by Tunnel-Structured Sepiolite

Polymers ◽

10.3390/polym11081286 ◽

2019 ◽

Vol 11 (8) ◽

pp. 1286 ◽

Cited By ~ 4

Author(s):

Li ◽

Gao ◽

Xia ◽

Li ◽

Zhou

Keyword(s):

Shear Strength ◽

Fracture Surface ◽

Cross Section ◽

Urea Formaldehyde ◽

Formaldehyde Emission ◽

Formaldehyde Resin ◽

Tunnel Structure ◽

Formaldehyde Release ◽

Uf Resin ◽

The Cost

In order to reduce the cost of plywood and save edible resources (wheat flour), a cheap and resourceful clay, sepiolite, was used to modify urea formaldehyde (UF) resin. The performances of filler-filled UF resins were characterized by measuring the thermal behavior, cross section, and functional groups. Results showed that cured UF resin with SEP (sepiolite) formed a toughened fracture surface, and the wet shear strength of the resultant plywood was maximum improved by 31.4%. The tunnel structure of SEP was beneficial to the releasing of formaldehyde, as a result, the formaldehyde emission of the plywood bonded by UF resin with SEP declined by 43.7% compared to that without SEP. This study provided a new idea to reduce the formaldehyde emission, i.e. accelerating formaldehyde release before the product is put into use.

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Development of a High-Performance Adhesive with a Microphase, Separation Crosslinking Structure Using Wheat Flour and a Hydroxymethyl Melamine Prepolymer

Polymers ◽

10.3390/polym11050893 ◽

2019 ◽

Vol 11 (5) ◽

pp. 893 ◽

Cited By ~ 1

Author(s):

Jieyu Zhang ◽

Yi Zhang ◽

Jianzhang Li ◽

Qiang Gao

Keyword(s):

Shear Strength ◽

Fracture Surface ◽

Bond Strength ◽

Wheat Flour ◽

High Performance ◽

Water Resistance ◽

Microphase Separation ◽

Low Cost ◽

Bond Performance ◽

Effective Manner

The objective of this study is to use wheat flour (WF) and hydroxymethyl melamine prepolymer (HMP) to develop a low cost, highly water-resistant, starch-based bio-adhesive for plywood fabrication. Three-layer plywood was fabricated using the resultant adhesive, and the wet shear strength of the plywood samples was measured under various conditions. After determining that water resistance was significantly improved with the addition of HMP, we evaluated the physical characteristics of the starch-based adhesive and functional groups and analyzed the thermal stability and fracture surface of the cured adhesive samples. Results showed that by adding 20 wt.% HMP into WF adhesive, the sedimentation volume in the resultant adhesive decreased by 11.3%, indicating that the increase of crosslinking in the structure of the adhesives increased the bond strength, and the wet shear strength of the resultant plywood in 63 °C water improved by 375% when compared with the WF adhesive. After increasing the addition of HMP to 40 wt.%, the wet shear strength of the resultant plywood in 100 °C water changed from 0 MPa to 0.71 MPa, which meets the exterior use plywood requirement. This water resistance and bond strength improvement resulted from (1) HMP reacting with functions in WF and forming a crosslinking structure to prevent moisture intrusion; and (2) HMP self-crosslinking and combining with crosslinked WF to form a microphase separation crosslinking structure, which improved both the crosslinking density and the toughness of the adhesive, and subsequently, the adhesive’s bond performance. In addition, the microphase separation crosslinking structure had better thermostability and created a compact ductile fracture surface, which further improved the bond performance of the adhesive. Thus, using a prepolymer to form a microphase separation crosslinking structure within the adhesive improves the rigidity, toughness, and water resistance of the material in a practical and cost-effective manner.

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Effect of ultrasonic vibration on interfacial reaction of Ni/Sn/Ni soldered joint

Soldering & Surface Mount Technology ◽

10.1108/ssmt-05-2019-0018 ◽

2019 ◽

Vol 32 (2) ◽

pp. 73-81

Author(s):

Yun Liu ◽

Weiyuan Yu ◽

Xuemin Sun ◽

Fengfeng Wang

Keyword(s):

Shear Strength ◽

Ultrasonic Vibration ◽

Grain Morphology ◽

Electronics Packaging ◽

Dispersion Strengthening ◽

Shear Tests ◽

Content Type ◽

Ultrasonic Assisted ◽

Surface Microstructures ◽

Soldered Joint

Purpose This paper aims to investigate the effect of ultrasonic vibration (USV) on the evolution of intermetallic compounds (IMCs), grain morphology and shear strength of soldered Ni/Sn/Ni samples. Design/methodology/approach The Ni/Sn/Ni joints were obtained through ultrasonic-assisted soldering. The formation of IMCs, their composition, grain morphology and the fractured-surface microstructures from shear tests were characterized using scanning electron microscopy and energy-dispersive x-ray spectroscopy. Findings Without USV, a planar interfacial Ni3Sn4 layer was formed at the Ni/Sn interface, and a few Ni3Sn4 grains were distributed in the soldered joint. The morphology of these grains was needle-shaped. With USV, several grooves were formed at the interfacial Ni3Sn4 layer due to ultrasonic cavitation. Some deepened grooves led to “neck” connections at the roots of the Ni3Sn4 grains, which accelerated the strong detachment of Ni3Sn4 from the substrate. In addition, two types of Ni3Sn4 grains, needle-shaped and granular-shaped, were observed at the interface. Furthermore, the shear strength increased with longer USV time, which was attributed to the thinning of the interfacial IMC layers and dispersion strengthening from the Ni3Sn4 particles distributed evenly in the joint. Originality/value The novelty of the paper is the detailed study of the effect of USV on the morphology, size changes of interfacial IMC and joint strength. This provides guidance for the application of ultrasonic-assisted soldering in electronics packaging.

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