Analysis of flip-chip packages using high resolution moire interferometry

Author(s):  
M.R. Miller ◽  
I. Mohammed ◽  
Xiang Dai ◽  
Ning Jiang ◽  
P.S. Ho
1996 ◽  
Vol 445 ◽  
Author(s):  
Xiang Dai ◽  
Connie Kim ◽  
Ralf Willecke ◽  
Paul S. Ho

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.


2006 ◽  
Vol 326-328 ◽  
pp. 517-520 ◽  
Author(s):  
Jin Hyoung Park ◽  
Chang Kyu Chung ◽  
Kyoung Wook Paik ◽  
Soon Bok Lee

Among many factors that influence the reliability of a flip-chip assembly using NCF interconnections, the most effective parameters are often the coefficient of thermal expansion (CTE), the modulus (E), and the glass transition temperatures (Tg). Of these factors, the effect of Tg on thermal deformation and device reliability is significant; however, it has not been shown clearly what effect Tg has on the reliability of NCF. The Tg of a conventional NCF material is approximately 110°C. In this study, a new high Tg NCF material that has a 140oC Tg is proposed. The thermal behaviors of the conventional and new NCFs between -40oC to 150oC are observed using an optical method. Twyman-Green interferometry and the moiré interferometry method are used to measure the thermal micro-deformations. The Twyman-Green interferometry measurement technique is applied to verify the stress-free state. The stress-free temperatures of the conventional and new Tg NCF materials are approximately 100oC and 120oC respectively. A shear strain at a part of the NCF chip edge is measured by moiré interferometry. Additionally, a method to accurately measure the residual warpage and shear strain at room temperature is proposed. Through the analysis of the relationship between the warpage and the shear strain, the effect of the high-Tg NCF material on the reliability is studied.


2002 ◽  
Vol 5 (7) ◽  
pp. 654-659
Author(s):  
Yasuyuki MORITA ◽  
Kazuo ARAKAWA ◽  
Mitsugu TODO ◽  
Masayuki KANETO

1998 ◽  
Vol 120 (2) ◽  
pp. 179-185 ◽  
Author(s):  
J. Wang ◽  
Z. Qian ◽  
D. Zou ◽  
S. Liu

In this paper, the creep behavior of a flip-chip package under a thermal load was investigated by using nonlinear finite element technique coupled with high density laser moire´ interferometry. The real-time moire´ interferometry technique was used to monitor and measure the time-dependent deformation of flip-chip packages during the test, while the finite element method was adapted to analyze the variation of stresses at edges and corners of interfaces with time by considering the viscoelastic properties of the underfill and the viscoplastic behavior of the solder balls. The results show that the creep behavior of the underfill and the solder balls does not have significant effect on the warpage of the flip-chip under the considered thermal load due to their constrained small volume. The variation of the time-dependent deformation in the flip-chip package caused by the creep behavior of the underfill and the solder balls is in the submicro scale. The maximum steady-state U-displacement is only reduced by up to 6.7 percent compared with the maximum initial state U-displacement. Likewise, the maximum steady-state V-displacement is merely reduced by up to 10 percent compared with the maximum initial state V-displacement. The creep behavior slightly weakens the warpage situation of the flip-chip package. However, the modeling results show that the localized stresses at corners and edges of interfaces greatly decrease due to the consideration of viscoelastic properties of the underfill and the viscoplastic properties of the solder balls, and, thereby, effectively preventing interfaces from cracking. In addition, the predicted deformation values of the flip-chip package obtained from the finite element analysis were compared with the test data obtained from the laser moire´ interferometry technique. It is shown that the deformation values of the flip-chip package predicted from the finite element analysis are in a fair agreement with those obtained from the test.


2005 ◽  
Vol 127 (2) ◽  
pp. 86-90 ◽  
Author(s):  
Woon-Seong Kwon ◽  
Myung-Jin Yim ◽  
Kyung-Wook Paik ◽  
Suk-Jin Ham ◽  
Soon-Bok Lee

One of the most important issues whether anisotropic conductive film (ACF) interconnection technology is suitable to be used for flip chip on organic board applications is thermal cycling reliability. In this study, thermally induced deformations and warpages of ACF flip chip assemblies as a function of distance from neutral point (DNP) and ACF materials properties were investigated using in situ high sensitivity moire´ interferometry. For a nondestructive failure analysis, scanning acoustic microscopy investigation was performed for tested assemblies. To elucidate the effects of ACF material properties and DNP on the thermal cycling reliability of ACF assembly, Weibull analysis for the lifetime estimation of ACF joint was performed, and compared with thermal deformations of ACF flip chip assembly investigated by moire´ interferometry. Results indicate that the properties of ACF have a significant role in the thermal deformation and reliability performance during thermal cycling testing. Therefore, optimized ACF properties can enhance ACF package reliability during thermal cycling regime.


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