Experimental study on the thermo-mechanical effects of underfill and low-CTE substrate in a flip-chip device

Morita, Yasuyuki; Arakawa, Kazuo; Todo, Mitsugu; Kaneto, Masayuki

doi:10.1016/j.microrel.2005.02.013

Cited by 13 publications

(6 citation statements)

References 5 publications

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“…Thus, the deformation incurred by the temperature increment is locked into the grating and recorded at room temperature. Numerous examples can be found in the literature [20,21,[23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41].…”

Section: Microelectronics Devicementioning

confidence: 99%

Recent Applications of Moiré Interferometry

Ifju

Han

2010

Exp Mech

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Moiré interferometry has been a valuable experimental technique for the understanding of the mechanical behavior of materials and structures. Over the last decade less emphasis has been placed on the development of the technique and more towards applications. This paper is a review article on recent applications using moiré interferometry in the fields of microelectronics devices, material characterization, micromechanics, residual stress, composite materials, fracture mechanics, and biomechanics. The general principles of moiré interferometry and advancement of techniques will not be discussed in this text, but references will be provided.

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Section: Microelectronics Devicementioning

confidence: 99%

Recent Applications of Moiré Interferometry

Ifju

Han

2010

Exp Mech

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“…The microscope scanning moiré method has been reported for residual strain/stress measurement of composite materials [14,15], and moiré interferometry has been applied to residual strain/stress measurement of electronic packages and composite materials [16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Residual Thermal Strain Distribution Measurement of Underfills in Flip Chip Electronic Packages by an Inverse Approach Based on the Sampling Moiré Method

Wang

Enomoto³

2020

Exp Mech

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Residual deformation evaluation of underfill (UF) materials in flip chips is crucial to improve the reliability of electronic packages. In this study, we propose to evaluate the residual thermal strain distributions using an inverse method based on the sampling moiré technique. Even if a grid pattern is fabricated on the specimen at room temperature, the residual strain distributions at an arbitrary temperature relative to the specimen formation temperature can be successfully calculated. The residual strain distributions relative to the free contraction state at an arbitrary temperature can also be measured when the coefficient of thermal expansion is available. A thermal chamber for flip chips was designed under a laser scanning microscope. Using the proposed method, the normal, shear and principal internal strain distributions and deformation characteristics of two kinds of UFs in flip chips were investigated relative to 150 °C. The strains of the UF with low glass transition temperature (UF-A) concentrate near the die material, especially at the die corner, while the strain concentration of the underfill with high glass transition temperature (UF-B) mainly occurs at the die corner and the buffer layer. The maximum principal strain of UF-A is greater than that of UF-B around the die corner. The residual maximum principal strain distributions relative to the free contraction state at 25 °C were compared with the simulation results by the finite element method. The residual strain distribution trends from experiments are consistent with those from simulations.

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“…Full capillary flow underfills (FCFUs) have been used for years to protect against the coefficient of thermal expansion (CTE) mismatch in flip chip ball grid array (BGA) packages and the effects of temperature cycling. [1][2][3][4][5][6][7][8] Eventually, the underfill approach extended to the printed circuit board arena. Underfill at the board level dominates markets such as cell phones, personal digital assistants, MP3 players, digital cameras, and automotive applications.…”

Section: Introductionmentioning

confidence: 99%

Thermomechanical Fatigue Performance of Lead-Free Chip Scale Package Assemblies with Fast Cure and Reworkable Capillary Flow Underfills

Shi

Tian

Ueda

2012

Jpn. J. Appl. Phys.

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In this paper, we present the results of temperature cycling test for full and partial capillary flow underfilled lead-free chip scale packages (CSPs), the tests were carried out on the basis of JEDEC standard. Two kinds of representative fast cure and reworkable underfill materials are used in this study, and CSPs without underfills were also tested for comparison. The test results show that the two underfill materials reduce the thermomechanical fatigue performance of CSP assemblies. The underfill with high T g and storage modulus yielded better performance; indeed, the coefficient of thermal expansion (CTE) is also very critical to the thermomechanical fatigue performance, but its effects is not so obvious in this study owing to the similar CTEs of the underfills used. In addition, the negative effect of a partial underfill pattern is smaller than that of a full underfill pattern. Failure analysis shows that the dominant failure mode observed is solder cracking near the package and/or printed circuit board pads.

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Experimental study on the thermo-mechanical effects of underfill and low-CTE substrate in a flip-chip device

Cited by 13 publications

References 5 publications

Recent Applications of Moiré Interferometry

Recent Applications of Moiré Interferometry

Residual Thermal Strain Distribution Measurement of Underfills in Flip Chip Electronic Packages by an Inverse Approach Based on the Sampling Moiré Method

Thermomechanical Fatigue Performance of Lead-Free Chip Scale Package Assemblies with Fast Cure and Reworkable Capillary Flow Underfills

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