Crack Propagation Experiments on Flip Chip Solder Joints

1998 ◽  
Vol 515 ◽  
Author(s):  
S. Wiese ◽  
F. Feustel ◽  
S. Rzepka ◽  
E. Meusel
Keyword(s):  
Crack Propagation ◽  
Flip Chip ◽  
Solder Joints ◽  
Shear Loading ◽  
Displacement Curve ◽  
In Situ Experiments ◽  
Propagation Experiment ◽  
Crack Propagation Experiment ◽  
Number Of Cycles ◽  
Force Displacement

ABSTRACTThe paper presents crack propagation experiments on real flip chip specimens applied to reversible shear loading. Two specially designed micro testers will be introduced. The first tester provides very precise measurements of the force displacement hysteresis. The achieved resolutions have been I mN for force and 20 nm for displacement. The second micro tester works similar to the first one, but is designed for in-situ experiments inside the SEM. Since it needs to be very small in size it reaches only resolutions of 10 mN and 100nm, which is sufficient to achieve equivalence to the first tester. A cyclic triangular strain wave is used as load profile for the crack propagation experiment. The experiment was done with both machines applying equivalent specimens and load. The force displacement curve was recorded using the first micro mechanical tester. From those hysteresis, the force amplitude has been determined for every cycle. All force amplitudes are plotted versus the number of cycles in order to quantify the crack length. With the second tester, images were taken at every 10th … 100th cycle in order to locate the crack propagation. Finally both results have been linked together for a combined quatitive and spatial description of the crack propagation in flip chip solder joints.

Misaligned Flip-Chip Solder Joints: Prediction and Experimental Determination of Force-Displacement Curves

2002 ◽  
Vol 124 (3) ◽  
pp. 227-233 ◽  
Author(s):  
D. Josell ◽  
W. E. Wallace ◽  
J. A. Warren ◽  
D. Wheeler ◽  
A. C. Powell
Keyword(s):  
Flip Chip ◽  
Solder Joints ◽  
Minimum Energy ◽  
Computer Code ◽  
Silicon Substrates ◽  
Surface Evolver ◽  
Solder Volume ◽  
Lateral Offset ◽  
Force Displacement

The results of wetting experiments between eutectic lead-tin solder and copper pads on silicon substrates in geometries relevant to flip-chip applications are presented. Measurements of solder joint dimensions, specifically stand-off height and lateral offset (i.e., misalignment), as functions of the applied force (normal and shear), solder volume and pad diameter are presented. The experimentally-measured force-displacement relationships are compared with predictions obtained from the minimum energy model of the Surface Evolver computer code. For the case of the axisymmetric joint (zero shear) an exact solution to the capillary equations is also presented. The comparison of experimental and modeling results indicates that such models are accurate as well as extremely sensitive means for predicting the geometry of these solder joints.

Study on the Damage Tolerance of a Stiffened Panel with a Skin Pad

2008 ◽  
Vol 33-37 ◽  
pp. 297-300
Author(s):  
Yi Li ◽  
Sheng Nan Wang
Keyword(s):  
Crack Propagation ◽  
Static Analysis ◽  
Damage Tolerance ◽  
Fortran Program ◽  
Structure Design ◽  
Stiffened Panel ◽  
Manufacturing Cost ◽  
Aircraft Structure ◽  
Propagation Experiment ◽  
Crack Propagation Experiment

During the development of an aircraft structure design, designers draw out a skin-stringer panel with a skin pad on the basis of a conventional skin-stringer panel(skin is directly connected with stringer by rivets or there was a sheet betweeen skin and stringers) to reduce the manufacturing cost. In this paper, we calculated the SIF of three kinds of skin-stringer panels by FE. And then, we analyze the damage tolerance of these structures by fortran program. Especially we carried out a crack propagation experiment of a skin-stringer panel with a skin pad and compared it with the results of a static analysis. Finally we researched the influence of the thickness of a skin pad on the damage tolerance. According to the researches above we concluded the advantages of the skin-stringer panel with a skin pad on the damage tolerance, and presented some suggestions about the thickness of a skin pad.

scholarly journals Modelling of Crack Propagation in Layered Structures Using Extended Finite Element Method

2016 ◽  
Vol 2 (5) ◽  
pp. 180-188 ◽  
Author(s):  
Hesamoddin Nasaj Moghaddam ◽  
Ali Keyhani ◽  
Iman Aghayan
Keyword(s):  
Finite Element Method ◽  
Crack Initiation ◽  
Crack Propagation ◽  
Young’S Modulus ◽  
Extended Finite Element Method ◽  
Young's Modulus ◽  
Displacement Curve ◽  
Extended Finite Element ◽  
Three Point Bending ◽  
Force Displacement

Crack propagation in structures is an important issue which is engineers and designers should consider. Modeling crack propagation in structures and study the behavior of this phenomenon can give a better insight to engineers and designers for selecting the construction’s materials. Extended finite element method (XFEM) was used successfully in the past few years for simulating crack initiation and propagation in sophisticated and complex geometries in elastic fracture mechanics. In this paper, crack propagation in three-point bending beam including initial crack was modeled based on ABAQUS software. The following consequences were attained through the study of simulation data. First, the effects of young’s modulus and fracture energy on force-displacement curve at three-point bending beam were investigated. It was observed that, by increasing the value of young’s modulus and fracture energy, three-point bending beam was showed more load carrying against initiation. Second, in multi-layer beam, the effect of young’s modulus on force-displacement curve was investigated. In case I (the thin upper layer is harder than the substrate) the value of young’s modulus in substrate was kept constant and the amount of young’s modulus in thin layer was risen in each step rather than the substrate, the peak in force-displacement curve was ascended and three-point bending beam resisted better against crack initiation. Next, similar conditions was considered in case II (the thin upper layer is softer than the substrate), by decreasing the value of young’ modulus in top layer, peak in force-displacement curve was declined and crack initiation was happened in lower loading in each step. Finally, sensitivity analysis for thickness of top layer was conducted and the impact of this parameter was studied.

scholarly journals Characteristic Tearing Energy and Fatigue Crack Propagation of Filled Natural Rubber

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3891
Author(s):  
Jigang Rong ◽  
Jun Yang ◽  
Youjian Huang ◽  
Wenbo Luo ◽  
Xiaoling Hu
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Pure Shear ◽  
Fatigue Loading ◽  
Propagation Length ◽  
Cutting Method ◽  
Tearing Energy ◽  
Propagation Experiment ◽  
Crack Propagation Experiment

Below the incipient characteristic tearing energy (T0), cracks will not grow in rubber under fatigue loading. Hence, determination of the characteristic tearing energy T0 is very important in the rubber industry. A rubber cutting experiment was conducted to determine the T0, using the cutting method proposed originally by Lake and Yeoh. Then, a fatigue crack propagation experiment on a edge-notched pure shear specimen under variable amplitude loading was studied. A method to obtain the crack propagation rate da/dN from the relationship of the crack propagation length (Δa) with the number of cycles (N) is proposed. Finally, the T0 obtained from the cutting method is compared with the value decided by the fatigue crack propagation experiment. The values of T0 obtained from the two different methods are a little different.

Application of Synchrotron Radiation X-Ray Laminography to Nondestructive Evaluation of the Fatigue Crack Propagation Process in Flip Chip Solder Joints

2013 ◽  
Author(s):  
Hiroyuki Tsuritani ◽  
Toshihiko Sayama ◽  
Yoshiyuki Okamoto ◽  
Takeshi Takayanagi ◽  
Kentaro Uesugi ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Synchrotron Radiation ◽  
Crack Propagation ◽  
Flip Chip ◽  
Solder Joints ◽  
Fatigue Cracks ◽  
Propagation Process ◽  
X Ray ◽  
Micro Cracks ◽  
Crack Propagation Process

The reliability and lifetime of micro-joints on printed circuit boards (PCBs) is significantly affected by fatigue processes, including fatigue crack initiation and propagation to failure. Accordingly, the industries producing electronic devices and components strongly desire the development of a new nondestructive inspection technology, which detects micro-cracks appearing as thermal fatigue fractures in these joints. Accordingly, the authors have demonstrated that the micro-cracks in the micro-solder joints can be observed using the SP-μCT synchrotron X-ray micro tomography system. However, in order for such solder joint micro-cracks to be observable by SP-μCT, the observation object must have a diameter of less than roughly 1 mm. In this investigation, we applied a synchrotron radiation X-ray laminography system to three-dimensionally and nondestructively evaluate the fatigue crack propagation process in flip chip solder micro-joints. X-ray laminography is a technique for nondestructively observing planar objects. The optical system developed for use in X-ray laminography was constructed to provide the rotation stage with a 20° tilt from the horizontally incident X-ray beam. For this reason, X-rays were sufficiently transmitted through the planar object, in all directions. The observed specimens had a flip chip structure, in which a 10.04 mm square LSI chip is connected to a 52.55 mm (length) × 30.0 mm (width) FR-4 substrate by 120 μm diameter Sn-3.0wt%Ag-0.5wt%Cu lead-free solder bumps. A thermal cycle test was carried out, and specimens were collected at fixed cycle numbers. The same solder joints were observed successively using the synchrotron radiation X-ray laminography system at beamline BL20XU at SPring-8, the largest synchrotron radiation facility in Japan. An X-ray beam energy of 29.0 keV was selected to obtain laminography images with high contrast among component. The obtained laminography images clearly show the evolution of cracks, voids, and the Ag3Sn phase due to the thermal cyclic loading of the solder joints. In addition, the surface area of the same fatigue cracks was also measured, to quantify the crack propagation process. However, the surface area change measured by laminography differed from the crack propagation results obtained by standard SP-μCT. This difference may be due to an inability to observe some micro-cracks, due to crack closure to beneath than the detection limit of synchrotron radiation X-ray laminography. Consequently, these results demonstrate the possibility that nondestructive observation of fatigue cracks in the solder bumps on a large size electronic substrate by synchrotron radiation X-ray laminography, although its detection ability for narrow cracks may be limited, compared to SP-μCT.

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