Critical Factors Affecting the Undercooling of Pb-free, Flip-Chip Solder Bumps and In-situ Observation of Solidification Process

2007 ◽  
Author(s):  
Sung K. Kang ◽  
Moon Gi Cho ◽  
Paul Lauro ◽  
Da-Yuan Shih
Keyword(s):  
Flip Chip ◽  
Solidification Process ◽  
In Situ Observation ◽  
Critical Factors ◽  
Factors Affecting ◽  
Solder Bumps

Study of the undercooling of Pb-free, flip-chip solder bumps and in situ observation of solidification process

2007 ◽  
Vol 22 (3) ◽  
pp. 557-560 ◽  
Author(s):  
Sung K. Kang ◽  
M.G. Cho ◽  
P. Lauro ◽  
Da-Yuan Shih
Keyword(s):  
Flip Chip ◽  
Solidification Process ◽  
In Situ Observation ◽  
Imaging Method ◽  
Scanning Calorimetry ◽  
Solder Bumps ◽  
Chip Size ◽  
Free Solder ◽  
Heating Up

The undercooling of flip-chip Pb-free solder bumps was investigated by differential scanning calorimetry (DSC) to understand the effects of solder composition and volume, with and without the presence of an under bump metallurgy (UBM). A large amount of the undercooling (as large as 90 °C) was observed with Sn-rich, flip-chip size solder bumps sitting in a glass mold, while the corresponding undercooling was significantly reduced in the presence of a wettable UBM surface. In addition, the solidification of an array of individual solder bumps was monitored in situ by a video imaging technique during both heating-up and cooling-down cycles. Data obtained by the optical imaging method were used to complement the DSC thermal measurements. A random solidification of the array of bumps was demonstrated during cooling, which also spans a wide temperature range of 40–80 °C. In contrast, an almost simultaneous melting of the bumps was observed during heating.

In Situ Observation of Macro and Micro Solidification Process in the Molten Pool during Laser Remelting

Applied laser ◽  
2015 ◽  
Vol 35 (1) ◽  
pp. 20-24
Author(s):  
王永辉 Wang Yonghui ◽  
林鑫 Lin Xin ◽  
王理林 Wang Lilin ◽  
杨海欧 Yang Haiou ◽  
黄卫东 Huang Weidong
Keyword(s):  
Molten Pool ◽  
Solidification Process ◽  
In Situ Observation ◽  
Laser Remelting

In-situ observation of material migration in flip-chip solder joints under current stressing

2006 ◽  
Vol 35 (10) ◽  
pp. 1781-1786 ◽  
Author(s):  
C. M. Tsai ◽  
Yi-Shao Lai ◽  
Y. L. Lin ◽  
C. W. Chang ◽  
C. R. Kao
Keyword(s):  
Flip Chip ◽  
Solder Joints ◽  
In Situ Observation ◽  
Current Stressing ◽  
Material Migration

Dendrite Grow up Relations with Cooling Speed

2013 ◽  
Vol 750-752 ◽  
pp. 473-476
Author(s):  
Qing Jun Zhang ◽  
Chun Liang Yan ◽  
Zhi Min Cui ◽  
Yao Guang Wu
Keyword(s):  
Cooling Rate ◽  
Structure Refinement ◽  
Dendritic Structure ◽  
Solidification Process ◽  
Confocal Laser ◽  
In Situ Observation ◽  
Dendrite Formation ◽  
Cooling Speed ◽  
Infrared Heater

Using confocal laser microscope with an infrared heater for 45 steel under different rate of solidification dendrite formation in the process of in situ observation, in the melt solidification phase has different cooling rate the cooling of dendrite formation, analysis of cooling rate on final solidified structure. Results show that with the reduction of temperature in the solidification process dendrite growth continuously, new nuclear has been formed, with the speeding up of the cooling rate, the dendritic structure refinement.

In Situ Observation of Solidification Process of AISI 304 Austenitic Stainless Steel

2008 ◽  
Vol 15 (6) ◽  
pp. 78-82 ◽  
Author(s):  
Fu-xiang Huang ◽  
Xin-hua Wang ◽  
Jiong-ming Zhang ◽  
Chen-xi Ji ◽  
Yuan Fang ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Solidification Process ◽  
In Situ Observation ◽  
Aisi 304 ◽  
304 Austenitic Stainless Steel

In‐Situ Mapping and Modeling Verification of Thermomechanical Deformation in Underfilled Flip‐Chip Packaging Using Moiré Interferometry

1996 ◽  
Vol 445 ◽  
Author(s):  
Xiang Dai ◽  
Connie Kim ◽  
Ralf Willecke ◽  
Paul S. Ho
Keyword(s):  
Flip Chip ◽  
Thermal Loading ◽  
Deformation Monitoring ◽  
Moiré Interferometry ◽  
Moire Interferometry ◽  
Fringe Analysis ◽  
Element Analysis ◽  
Solder Bumps ◽  
Thermomechanical Deformation

AbstractAn experimental technique of environmental moiré interferometry has been developed for in‐situ monitoring and analysis of thermomechanical deformation of microelectronics packages subjected to thermal loading under a controlled atmosphere. Coupled with fractional fringe analysis and digital image processing, the environmental moiré interferometry technique achieves accurate and realistic deformation monitoring with high sensitivity and excellent spatial resolution. It has been applied to investigate the thermomechanical deformations induced by thermal loading in an underfilled flip‐chip‐on‐board packaging. The effects of temperature change in the range of 102 °C to 22 °C are analyzed for underfill and solder bumps. In addition, shear deformation and shear strains across the solder bumps are determined as a function of temperature. The experimental results are compared with the results of a finite element analysis for modeling verification. Good agreement between the modeling results and experimental measurements has been found in the overall displacement fields. Through this study, the role of underfill in the thermomechanical deformation of the underfilled flip‐chip package is determined.

scholarly journals Modelling In-situ Factors Affecting Bud’s Growth of Rafflesia kerrii Meijer in Lojing Highlands, Kelantan, Peninsular Malaysia

2021 ◽  
Vol 29 (2) ◽  
Author(s):  
Abdul Hamid Mar Iman ◽  
Nor Hizami Hassin ◽  
Muhamad Azahar Abas ◽  
Zulhazman Hamzah
Keyword(s):  
Data Collection ◽  
Ecological Factors ◽  
Geographic Area ◽  
Ordinary Least Squares ◽  
Peninsular Malaysia ◽  
In Situ Observation ◽  
Cross Sectional ◽  
Factors Affecting ◽  
Consistent Error

Studies on the statistical approach to analyzing growth factors of bud’s growth in the genus Rafflesia have been lacking. This study quantified the effects of eight selected ecological factors hypothesized to be influencing bud’s growth (diameter and circumference) of Rafflesia kerrii Meijer. A non-experimental cross-sectional data collection was conducted between April and August 2018 by in-situ observation and measurements on eight ecological factors utilizing thirty-four sampled individual plants in Lojing Highlands, Kelantan, Peninsular Malaysia. The Ordinary Least Squares (OLS) and Heteroscedasticity-Consistent- Error (HCE) OLS regression models were employed to establish the statistical relationship between bud’s growth and its influencing factors. Host plant’s ecological ability, level of temperature, light shading, soil acidity, and interaction between plant survival condition and growth stage were found to be the significant and influential ecological factors to bud’s growth of Rafflesia kerrii. The results also showed that, model wise, HCE OLS models outperformed the OLS models in explaining the cause-and-effect relationship under study. Due to some limitations in sampling and data collection, further studies were recommended to corroborate this study using a larger sample covering a larger geographic area – possibly across different localities.

scholarly journals Dendritic Growth in Si1−xGex Melts

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 761
Author(s):  
Genki Takakura ◽  
Mukannan Arivanandhan ◽  
Kensaku Maeda ◽  
Lu-Chung Chuang ◽  
Keiji Shiga ◽  
...  
Keyword(s):  
Dendritic Growth ◽  
Elevated Temperatures ◽  
Electronic Devices ◽  
Solidification Process ◽  
Dendrite Growth ◽  
In Situ Observation ◽  
Wide Range ◽  
Solidification Processes ◽  
Semiconductor Alloy

We investigated the types of dendrites grown in Si1−xGex (0 < x < 1) melts, and also investigated the initiation of dendrite growth during unidirectional growth of Si1-xGex alloys. Si1−xGex (0 < x < 1) is a semiconductor alloy with a completely miscible-type binary phase diagram. Therefore, Si1−xGex alloys are promising for use as epitaxial substrates for electronic devices owing to the fact that their band gap and lattice constant can be tuned by selecting the proper composition, and also for thermoelectric applications at elevated temperatures. On the other hand, regarding the fundamentals of solidification, some phenomena during the solidification process have not been clarified completely. Dendrite growth is a well-known phenomenon, which appears during the solidification processes of various materials. However, the details of dendrite growth in Si1−xGex (0 < x < 1) melts have not yet been reported. We attempted to observe dendritic growth in Si1−xGex (0 < x < 1) melts over a wide range of composition by an in situ observation technique. It was found that twin-related dendrites appear in Si1−xGex (0 < x < 1) melts. It was also found that faceted dendrites can be grown in directional solidification before instability of the crystal/melt interface occurs, when a growing crystal contains parallel twin boundaries.

In Situ Observation of Solidification in Horizontal Centrifugal Casting Process

2010 ◽  
Vol 649 ◽  
pp. 325-330 ◽  
Author(s):  
Hisao Esaka ◽  
Jun-Nichi Hiramoto ◽  
Shota Miyahara ◽  
Kei Shinozuka
Keyword(s):  
Centrifugal Casting ◽  
Solidification Process ◽  
Casting Process ◽  
Tangential Direction ◽  
In Situ Observation ◽  
Permanent Mold ◽  
Metal Solidification ◽  
Water Pipes ◽  
Made In

Horizontal centrifugal casting is widely used for production of water pipes, rolls and so on. Advantage of this process is to press molten metal against the permanent mold due to centrifugal force. Thanks to this, one can obtain fine structure and sound castings1). On the other hand, macroscopic segregation on tangential direction sometimes forms. The formation mechanism of macroscopic segregation has not well understood. This is because the solidification process itself is still uncertain since it is very complex2-4). Thus, in order to understand the solidification process in horizontal centrifugal casting an in-situ observation has been made in this study. Transparent organic substance has been used to simulate the metal solidification.

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