In Situ Synchrotron Characterization of Melting, Dissolution, and Resolidification in Lead-Free Solders

Zhou, Bowen; Bieler, T. R.; Wu, Guilin; Zaefferer, Stefan; Lee, Tae‐Kyu; Liu, Kuo Chuan

doi:10.1007/s11664-011-1785-8

Cited by 12 publications

(4 citation statements)

References 21 publications

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“…25 In situ measurements of melting and solidification were also investigated using synchrotron beam line 6ID-D using a wafer-level chip-scale package (WLCSP) with 250-lm solder balls in a 0.5-mmpitch 10 9 10 array directly attached to a 6 mm 9 7 mm silicon die. 27 The beam size included the whole corner ball, the underbump metallurgy, and a small part of the silicon. Multiple samples were reflowed using a history similar to industrial practice, with as many as four reflow events.…”

Section: Methodsmentioning

confidence: 99%

The Role of Elastic and Plastic Anisotropy of Sn in Recrystallization and Damage Evolution During Thermal Cycling in SAC305 Solder Joints

Bieler

Zhou

Blair

et al. 2011

Journal of Elec Materi

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104

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Because failures in lead-free solder joints occur at locations other than the most highly shear-strained regions, reliability prediction is challenging. To gain physical understanding of this phenomenon, physically based understanding of how elastic and plastic deformation anisotropy affect microstructural evolution during thermomechanical cycling is necessary. Upon solidification, SAC305 (Sn-3.0Ag-0.5Cu) solder joints are usually single or tricrystals. The evolution of microstructures and properties is characterized statistically using optical and orientation imaging microscopy. In situ synchrotron x-ray measurements during thermal cycling are used to examine how crystal orientation and thermal cycling history change strain history. Extensive characterization of a low-stress plastic ball grid array (PBGA) package design at different stages of cycling history is compared with preliminary experiments using higherstress package designs. With time and thermal history, microstructural evolution occurs mostly from continuous recrystallization and particle coarsening that is unique to each joint, because of the specific interaction between local thermal and displacement boundary conditions and the strong anisotropic elastic, plastic, expansion, and diffusional properties of Sn crystals. The rate of development of recrystallized microstructures is a strong function of strain and aging. Cracks form at recrystallized (random) boundaries, and then percolate through recrystallized regions. Complications arising from electromigration and corrosion are also considered.

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Section: Methodsmentioning

confidence: 99%

The Role of Elastic and Plastic Anisotropy of Sn in Recrystallization and Damage Evolution During Thermal Cycling in SAC305 Solder Joints

Bieler

Zhou

Blair

et al. 2011

Journal of Elec Materi

Self Cite

104

View full text Add to dashboard Cite

show abstract

“…Around the world synchrotron radiation facilities have designated tomography and diffraction beamlines that are used for failure analysis of microelectronic packages. Some examples of this are imaging void formation caused by electromigration [1][2][3] , evaluating mechanisms for tin whisker growth 4,5 , in situ observations of undercooling and anisotropic thermal expansion of tin and intermetallic compounds (IMCs) 6,7 , in situ observation of solidification and IMC formation [8][9][10] , anisotropic mechanical behavior and recrystallization of tin and lead free solders 10 , voids in flip chip bumps, and in situ observations of Ag-nanoink sintering 11 . All of these studies have further advanced the understanding and development of components in the microelectronic industry.…”

Section: Introductionmentioning

confidence: 99%

Using Synchrotron Radiation Microtomography to Investigate Multi-scale Three-dimensional Microelectronic Packages

Carlton

Elmer

et al. 2016

JoVE

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Synchrotron radiation micro-tomography (SRµT) is a non-destructive three-dimensional (3D) imaging technique that offers high flux for fast data acquisition times with high spatial resolution. In the electronics industry there is serious interest in performing failure analysis on 3D microelectronic packages, many which contain multiple levels of high-density interconnections. Often in tomography there is a trade-off between image resolution and the volume of a sample that can be imaged. This inverse relationship limits the usefulness of conventional computed tomography (CT) systems since a microelectronic package is often large in cross sectional area 100-3,600 mm(2), but has important features on the micron scale. The micro-tomography beamline at the Advanced Light Source (ALS), in Berkeley, CA USA, has a setup which is adaptable and can be tailored to a sample's properties, i.e., density, thickness, etc., with a maximum allowable cross-section of 36 x 36 mm. This setup also has the option of being either monochromatic in the energy range ~7-43 keV or operating with maximum flux in white light mode using a polychromatic beam. Presented here are details of the experimental steps taken to image an entire 16 x 16 mm system within a package, in order to obtain 3D images of the system with a spatial resolution of 8.7 µm all within a scan time of less than 3 min. Also shown are results from packages scanned in different orientations and a sectioned package for higher resolution imaging. In contrast a conventional CT system would take hours to record data with potentially poorer resolution. Indeed, the ratio of field-of-view to throughput time is much higher when using the synchrotron radiation tomography setup. The description below of the experimental setup can be implemented and adapted for use with many other multi-materials.

show abstract

Section: Introductionmentioning

confidence: 99%

Using Synchrotron Radiation Microtomography to Investigate Multi-scale Three-dimensional Microelectronic Packages

Carlton¹,

Elmer²,

Li³

et al. 2016

JoVE

View full text Add to dashboard Cite

Synchrotron radiation micro-tomography (SRµT) is a non-destructive three-dimensional (3D) imaging technique that offers high flux for fast data acquisition times with high spatial resolution. In the electronics industry there is serious interest in performing failure analysis on 3D microelectronic packages, many which contain multiple levels of high-density interconnections. Often in tomography there is a trade-off between image resolution and the volume of a sample that can be imaged. This inverse relationship limits the usefulness of conventional computed tomography (CT) systems since a microelectronic package is often large in cross sectional area 100-3,600 mm 2 , but has important features on the micron scale. The micro-tomography beamline at the Advanced Light Source (ALS), in Berkeley, CA USA, has a setup which is adaptable and can be tailored to a sample's properties, i.e., density, thickness, etc., with a maximum allowable cross-section of 36 x 36 mm. This setup also has the option of being either monochromatic in the energy range ~7-43 keV or operating with maximum flux in white light mode using a polychromatic beam. Presented here are details of the experimental steps taken to image an entire 16 x 16 mm system within a package, in order to obtain 3D images of the system with a spatial resolution of 8.7 µm all within a scan time of less than 3 min. Also shown are results from packages scanned in different orientations and a sectioned package for higher resolution imaging. In contrast a conventional CT system would take hours to record data with potentially poorer resolution. Indeed, the ratio of field-of-view to throughput time is much higher when using the synchrotron radiation tomography setup. The description below of the experimental setup can be implemented and adapted for use with many other multi-materials.

show abstract

In Situ Synchrotron Characterization of Melting, Dissolution, and Resolidification in Lead-Free Solders

Cited by 12 publications

References 21 publications

The Role of Elastic and Plastic Anisotropy of Sn in Recrystallization and Damage Evolution During Thermal Cycling in SAC305 Solder Joints

The Role of Elastic and Plastic Anisotropy of Sn in Recrystallization and Damage Evolution During Thermal Cycling in SAC305 Solder Joints

Using Synchrotron Radiation Microtomography to Investigate Multi-scale Three-dimensional Microelectronic Packages

Using Synchrotron Radiation Microtomography to Investigate Multi-scale Three-dimensional Microelectronic Packages

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