Novel Test Methods for Die Strength

2005 ◽  
Author(s):  
M. Y. Tsai ◽  
C. H. Chen ◽  
C. S. Lin
Keyword(s):  
High Performance ◽  
Axial Stress ◽  
Test Methods ◽  
Bending Test ◽  
Published Data ◽  
Failure Strength ◽  
Element Analysis ◽  
Surface Conditions ◽  
Four Point Bending ◽  
Four Point Bending Test

Recently, the 3-D or stacked-die packages are increasingly popular for packaging ICs into a system or subsystem to satisfy the needs of low cost, small form factor, and high performance. For the applications of these packages, IC wafers have to be ground to be relatively thin through the wafers thinning processes (such as grinding, polishing, and plasma etching). The strength of dies has to be determined for the design requirement and thus assuring reliability of the packages. From the published data, there still exist some issues including a large scatter existed in die strength data, and difficulties with differentiating the causes of the low strength from the grinding or die sawing either by three-point bending or four-point bending test. The purposes of this study is to develop new, reliable and simple test methods for determination of die strength to improve the data scatter and also provide a solution for differentiating the factors that affect the variability of die strength, in order to find out the causes of the weakness of the die strength. In this study, two new test methods, point-loaded circular plate with simple supports test (PLT-I) and point-loaded plate on elastic foundation test (PLT-II) are proposed and evaluated by testing two groups of silicon dies with different surface conditions. The surface conditions (roughness) of the specimens are determined by atomic force microscopy and correlated to failure strength. The failure forces from both tests have to be modified by using maximum stress obtained from theory or finite element analysis to get the failure strength. The test results are compared with each other and further with widely-used four-point bending test. The results suggest that, unlike the four-point bending test, both methods provide very consistent data with a small scatter for these two groups of specimens, and indicated the die strength is highly dependent on the surface roughness. Accordingly, these two methods can provide not only a (bi-axial) stress field similar to temperature-loaded die in the packages, but also simple, feasible, reliable and chipping-free tests for silicon dies of dummy or real IC chips, without strict geometrical limitation, such as beam-type geometry for three-point or four-point bending test.

Test Methods for Silicon Die Strength

2006 ◽  
Vol 128 (4) ◽  
pp. 419-426 ◽  
Author(s):  
M. Y. Tsai ◽  
C. H. Chen ◽  
C. S. Lin
Keyword(s):  
High Performance ◽  
Low Cost ◽  
Test Methods ◽  
Biaxial Stress ◽  
Bending Test ◽  
Published Data ◽  
Failure Strength ◽  
Surface Conditions ◽  
Four Point Bending ◽  
Four Point Bending Test

Recently, the 3D or stacked-die packages become increasingly popular for packaging ICs into a system or subsystem to satisfy the needs of low cost, small form factor, and high performance. For the applications of these packages, IC silicon wafers have to be ground to be relatively thin through the wafer-thinning processes (such as grinding, polishing, and plasma etching). The strength of dies has to be determined for the design requirement and reliability assurance of the packages. From the published data, there still exist some issues, including a large scatter existed in die strength data and difficulties in differentiating the causes of the low strength between from the wafer grinding and from wafer sawing by either the three-point bending or four-point bending test. The purposes of this study are to develop new, reliable, and simple test methods for determination of die strength, in order to improve the data scatter, and to provide a solution for differentiating the factors that affect the variability of die strength for finding out the causes of the weakness of the die strength. In this study, two new test methods, point-loaded circular plate with simple supports test (PLT-I) and point-loaded plate on elastic foundation test (PLT-II), are proposed and then evaluated by testing two groups of silicon dies with different surface conditions. The surface conditions (roughness) of the specimens are determined by atomic force microscopy and correlated to failure strength. The failure forces from both tests have to be modified by using maximum stress obtained from theories or finite element analyses to obtain the failure strength. The test results are compared to each other and further with a widely used four-point bending test. The results suggest that, unlike the four-point bending test suffering the chipping effect, both methods provide very consistent data with a small scatter for each group of specimens and can be used for identifying the effect of surface grinding (roughness) on the die strength. It is also shown that the die strength is highly dependent on the surface roughness. Accordingly, these two methods can provide not only a (biaxial) stress field similar to temperature-loaded die in the packages, but also simple, feasible, reliable, and chipping-free tests for silicon dies of dummy or real IC chips, without strict geometrical limitation, such as beam-type geometry for the three-point or four-point bending test.

Failure Strengths of Composite Additions and Repairs

2015 ◽  
Vol 40 (4) ◽  
pp. 364-371 ◽  
Author(s):  
D Tantbirojn ◽  
C Fernando ◽  
A Versluis
Keyword(s):  
Bending Test ◽  
Failure Strength ◽  
Test Beam ◽  
Four Point Bending ◽  
Significant Difference ◽  
Control Failure ◽  
Four Point Bending Test ◽  
Composite Substrates ◽  
Aged Composite ◽  
Mechanical Surface

SUMMARY Purpose When adding composite to a cured composite restoration, the intent is to achieve the same failure strength as the original restorative material. This study evaluated the failure strengths of added or repaired composite using various chemical and/or mechanical surface treatments. Methods Failure strengths were determined using a four-point bending test. Beam-shaped specimens were fabricated by adding new composite to cured composite (Filtek Supreme Ultra). The cured composites were either fresh or aged seven days (N=10-14). The composite surfaces were left unground or were ground before treatment with various combinations of roughening, acid etching, silane, and dental adhesives (conventional Adper SingleBond Plus or new multimode Scotchbond Universal) and/or tribochemistry (CoJet system). Monolithic composite specimens were the control. Failure strengths were statistically analyzed using one-way analysis of variance and the Fisher protected least significant difference (α=0.05). Results Failure strengths (mean ± standard deviation) when composite was added to unground freshly cured composites (111±25 MPa) and aged composites using a new multimode adhesive with (102±22 MPa) or without (98±22 MPa) tribochemical treatment were not significantly lower than the monolithic specimens (122±23 MPa). Grinding the surfaces of freshly cured composite significantly reduced failure strength, either with (81±30 MPa) or without (86±31 MPa) use of conventional adhesive. Failure strengths of aged composites were also significantly lower (51±21 MPa with SingleBond Plus), even after tribochemical treatment (71±29 MPa with SingleBond Plus; 73±35 MPa with Silane-Visiobond). Conclusions Using a new multimode adhesive when adding composite to freshly cured or aged composite substrates recovered the failure strength to that of the original monolithic composite.

scholarly journals Comparison of the two point bending and four point bending test methods for aged asphalt concrete field samples

2014 ◽  
Vol 48 (9) ◽  
pp. 2901-2913 ◽  
Author(s):  
Lily D. Poulikakos ◽  
Michel Pittet ◽  
Andre-Gilles Dumont ◽  
Manfred N. Partl
Keyword(s):  
Asphalt Concrete ◽  
Test Methods ◽  
Bending Test ◽  
Four Point Bending ◽  
Field Samples ◽  
Aged Asphalt ◽  
Four Point Bending Test

Sandwich Beam in Four-Point Bending Test: Experiment and Numerical Models

2014 ◽  
Vol 969 ◽  
pp. 316-319 ◽  
Author(s):  
Stanislav Piovár ◽  
Eva Kormaníková
Keyword(s):  
Stress Condition ◽  
Numerical Models ◽  
Sandwich Beam ◽  
Bending Test ◽  
Plane Stress Condition ◽  
Element Analysis ◽  
The Core ◽  
Four Point Bending ◽  
The Finite Element Analysis ◽  
Four Point Bending Test

The numerical modeling of lightweight sandwich beam in four-point bending, using combination of finite elements by help of two modeling approaches 2-D and 3-D models is presented. The mechanical results of hot-dipped zinc steel face layers and polyurethane foam core, obtained from comprehensive material testing program, were used as input data in order to implement the finite element analysis by the commercial ANSYS code. The material nonlinearities, most pronounced in the core, as well as geometric nonlinearities are included in the models. As was shown an advantage of plane stress condition can be applied in numerical models in one-way bending.

Bending Deformation Performance of Underground Pipe for Power Transmission

2020 ◽  
Author(s):  
Michiya Sakai ◽  
Shinichi Matsuura ◽  
Masahiro Yoshimoto ◽  
Satoshi Takenaka ◽  
Jin Saito
Keyword(s):  
Power Transmission ◽  
Bending Test ◽  
Straight Pipe ◽  
Limit States ◽  
Element Analysis ◽  
Buckling Strength ◽  
Bending Deformation ◽  
Four Point Bending ◽  
Pipe Model ◽  
Four Point Bending Test

Abstract In order to clarify the ultimate strength of the Pipe type Oil Filled (POF) steel pipe, the four-point bending test of a straight pipe was performed using buried pipes for power transmission, and the ultimate behavior related to bending deformation performance was confirmed. The straight pipe model under the condition of joint and axial force as parameters was tested, and the limit states against ovalization due to buckling of pipe were shown. Based on the experimental results, we performed finite element analysis (FEA) by detailed modeling for the four-point bending test of a straight pipe, confirmed the analysis accuracy, and showed that it was possible to evaluate even local deformation due to buckling. The test results were evaluated by the buckling strength formula of the cylindrical shell, it was confirmed that the maximum buckling strength can be assessed conservatively and rationally.

Mechanical Properties of Fiber Reinforced Lime-Based Mortars Evaluated from Four-Point Bending Test

2016 ◽  
Vol 821 ◽  
pp. 526-531
Author(s):  
Michal Přinosil ◽  
Petr Kabele
Keyword(s):  
Thermal Effects ◽  
High Performance ◽  
Correlation Method ◽  
Image Correlation ◽  
Bending Test ◽  
Fiber Reinforced ◽  
Four Point Bending ◽  
High Performance Fiber ◽  
Bending Behavior ◽  
Four Point Bending Test

In the study, the bending behavior of high-performance fiber reinforced lime-based mortars is experimentally investigated using four-point bending test. From the experimental data, the influence of the mortar’s composition on its stiffness, cracking strength and ultimate strength are investigated. It is also studied, whether the response has strain-softening or strain-hardening character and whether the material exhibits multiple cracking. Such behavior is very important for the durability of the material, because it allows carrying load during imposed deformations (due to thermal effects, movements of foundations, seismicity, etc.). The number of formed cracks is examined using digital image correlation method. The mortar composition is considered with two types of binder (pure lime, lime-metakaolin), with two types of polyvinyl alcohol fibers in four volume fractions (0.5÷2.0%). As the reference, we consider two sets of specimens made of plain mortar without fiber reinforcement.

scholarly journals Structural behaviour of PSCC slab panel under four-point bending test

2021 ◽  
Vol 1144 (1) ◽  
pp. 012039
Author(s):  
M A Iman ◽  
N Mohamad ◽  
A A A Samad ◽  
Steafenie George ◽  
M A Tambichik ◽  
...  
Keyword(s):  
Bending Test ◽  
Structural Behaviour ◽  
Four Point Bending ◽  
Four Point Bending Test
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