Characterization of Epoxy-Functionalized Silsesquioxanes as Potential Underfill Encapsulants

1998 ◽  
Vol 519 ◽  
Author(s):  
E. K. Lin ◽  
C. R. Snyder ◽  
F. I. Mopsik ◽  
W. E. Wallace ◽  
W. L. Wu ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Flip Chip ◽  
Coefficient Of Thermal Expansion ◽  
Silica Particles ◽  
Critical Parameters ◽  
Organic Hybrid ◽  
Solder Bumps ◽  
The Difference ◽  
Electronics Packages

AbstractIn electronics packaging, underfill encapsulants are needed to improve package reliability in flip-chip devices. The underfill generally consists of an epoxy resin highly filled with silica particles and is designed to reduce the stress arising from the difference in the thermal expansion between the solder bumps and the substrate. Currently, concerns about the flow of the silica particles and surface phenomena are arising as electronics packages reduce in size. Newly developed epoxy-functionalized octameric silsesquioxanes provide an intriguing alternative to current formulations. These single-phase inorganic/organic hybrid materials may have properties similar to filled materials without the complications from the rheology of filled materials. The physical properties of the functionalized silsesquioxanes are measured with respect to the critical parameters for underfill materials. Measurements of properties such as the coefficient of thermal expansion and density are performed to evaluate the suitability of these materials as potential underfill encapsulants.

Application of an Epoxy Cap in a Flip-Chip Package Design

1989 ◽  
Vol 111 (1) ◽  
pp. 16-20 ◽  
Author(s):  
E. Suhir
Keyword(s):  
Thermal Expansion ◽  
Flip Chip ◽  
Coefficient Of Thermal Expansion ◽  
Preliminary Test ◽  
Elastic Stability ◽  
Thermally Induced ◽  
Package Design ◽  
Silicone Gels ◽  
Low Modulus ◽  
Supporting Frame

In order to combine the merits of epoxies, which provide good environmental and mechanical protection, and the merits of silicone gels, resulting in low stresses, one can use an encapsulation version, where a low modulus gel is utilized as a major encapsulant, while epoxy is applied as a protecting cap. Such an encapsulation version is currently under consideration, parallel with a metal cap version, for the Advanced VLSI package design which is being developed at AT&T Bell Laboratories. We recommend that the coefficient of thermal expansion for the epoxy be somewhat smaller than the coefficient of thermal expansion for the supporting frame. In this case the thermally induced displacements would result in a desirable tightness in the cap/frame interface. This paper is aimed at the assessment of stresses, which could arise in the supporting frame and in the epoxy cap at low temperatures. Also, the elastic stability of the cap, subjected to compression, is evaluated. The calculations were executed for the Advanced VLSI package design and for a Solder Test Vehicle (STV), which is currently used to obtain preliminary information regarding the performance of the candidate encapsulants. It is concluded that in order to avoid buckling of the cap, the latter should not be thinner than 15 mils (0.40 mm) in the case of VLSI package design and than 17.5 mils (0.45 mm) in the case of STV. At the same time, the thickness of the cap should not be greater than necessary, both for smaller stresses in the cap and for sufficient undercap space, required for wirebond encapsulation. The obtained formulas enable one to evaluate the actual and the buckling stresses. Preliminary test data, obtained by using STV samples, confirmed the feasibility of the application of an epoxy cap in a flip-chip package design.

Bilayer graded Al/B4C/rice husk ash composite: Wettability behavior, thermo-mechanical, and electrical properties

2018 ◽  
Vol 52 (27) ◽  
pp. 3745-3758 ◽  
Author(s):  
Amin Bahrami ◽  
Niloofar Soltani ◽  
Martin I Pech-Canul ◽  
Shaghayegh Soltani ◽  
Luis A González ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Thermal Expansion ◽  
Aluminum Alloys ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Material Selection ◽  
Coefficient Of Thermal Expansion ◽  
Thermal Expansion Coefficients ◽  
One Step ◽  
The Difference

In this study, wettability behavior of B4C substrate as well as B4C/crystalline rice husk ash and B4C/amorphous rice husk ash substrates with two aluminum alloys were studied. The electrical resistivity, thermal expansion coefficients, and thermal diffusivity of bilayer Al/B4C/rice husk ash composite fabricated by one-step pressureless infiltration were measured and the obtained data were systemically analyzed using the Taguchi method and analysis of variance. Boron carbide substrates after addition of amorphous or crystalline rice husk ash display good wettability with molten aluminum alloys. The results show that, electrical resistivity of Al/B4C/rice husk ash composites is mainly influenced by initial preform porosity, while the coefficient of thermal expansion of composites is determined by the chemical composition of infiltrated alloys. The measured values for coefficient of thermal expansion (10.5 × 10−6/℃) and electrical resistivity (0.60 × 10−5 Ω.m) of Al/B4C/rice husk ash composites, fabricated according to analysis of variance's optimal conditions are in good agreement with those of the projected values (11.02 × 10−6/℃ and 0.65 × 10−5 Ω.m, respectively). The difference between the corresponding values obtained from verification tests and projected values, for electrical resistivity and coefficient of thermal expansion are less than 5%. Finally, as a material selection approach, the strengths and weaknesses of the composites have been graphed in the form of radar diagrams.

scholarly journals Thermal analysis of metal-ceramic bonding using finite element method

2014 ◽  
Vol 3 (2) ◽  
pp. 216 ◽  
Author(s):  
S. Gopinath ◽  
R Sabarish ◽  
R. Sasidharan
Keyword(s):  
Finite Element ◽  
Thermal Expansion ◽  
Thermal Stress ◽  
Bonding Strength ◽  
Coefficient Of Thermal Expansion ◽  
Linear Thermal Expansion ◽  
Processing Temperature ◽  
Element Analysis ◽  
Metal Ceramic ◽  
The Difference

This paper reports a finite element study of effect of bonding strength between metal and ceramic. The bonding strength is evaluated with different processing temperature and holding time. The difference between the coefficients of linear thermal expansion (CTEs) of the metal and ceramic induces thermal stress at the interface. The mismatch thermal stress at the interface region plays an important role in improving bonding strength. Hence, it is essential to evaluate the interface bonding in metal-ceramics joints. The Al/SiC bonding was modeled and analyzed using finite element analysis in ANSYS (v.10). Keywords: Bonding Strength, Coefficient of Thermal Expansion, Thermal Stress, Interface, Al/Sic, FEA.

Reliability of Sn-Ag-Cu Flip Chip Package with Underfill under Thermal Shock

2006 ◽  
Vol 510-511 ◽  
pp. 558-561 ◽  
Author(s):  
Bo In Noh ◽  
Seung Boo Jung
Keyword(s):  
Thermal Expansion ◽  
Thermal Shock ◽  
Solder Ball ◽  
Flip Chip ◽  
Coefficient Of Thermal Expansion ◽  
Fatigue Property ◽  
Electroless Nickel ◽  
Fatigue Properties ◽  
Electroless Nickel Immersion Gold ◽  
Better Than

Thermal fatigue properties of solder joints encapsulated with underfill were studied conducting thermal shock tests. Flip chip package with electroless nickel-immersion gold plated on FR-4 substrate and the Sn-3.0Ag-0.5Cu solder ball was used. The fatigue property of package with underfill was better than the package without it. The fatigue property of package with underfill which has a higher glass transition temperature (Tg) and lower coefficient of thermal expansion (CTE) was better than that of package with underfill with lower Tg and higher CTE.

Effects of Hybrid Structures on the Stress Reduction and Thermal Properties of Joints in Electronics Devices

2016 ◽  
Vol 879 ◽  
pp. 1258-1264
Author(s):  
Michiya Matsushima ◽  
Noriyasu Nakashima ◽  
Satoshi Nishioka ◽  
Shinji Fukumoto ◽  
Kozo Fujimoto
Keyword(s):  
Thermal Expansion ◽  
Epoxy Resin ◽  
Stress Reduction ◽  
Analytical Study ◽  
Coefficient Of Thermal Expansion ◽  
Conductive Adhesives ◽  
Silicon Chips ◽  
Composite Joint ◽  
The Difference ◽  
Reduction Effect

Electronics devices consist of silicon chips, copper leads, resin or ceramics substrates and which are jointed to each other with solder, conductive adhesive or other materials. Each coefficient of thermal expansion is different and it causes strain concentration and cracks. The solder easily deformed by the difference of the thermal expansion and it relieved the stress on the devices however the epoxy resin of the conductive adhesives are harder. So we suggested the composed joint including the relaxation layers of low elastic material. The shear strength and elongation of the epoxy resin joint, silicone rubber joint and the composite joint of the two materials were investigated. The analytical study was carried out to clarify the stress reduction effect of the design of the relaxation layer in the composite joints. The parameters such as the width, height, pitch and the distance of the relaxation layer from the joint edge are investigated. The high relaxation layer close to the joint edge effectively reduced the stress of the joint. The stress reduction effect appeared in the different pitch of the layers.

Visco-Elastic Effect of Underfill Material in Reliability Analysis of Flip-Chip Package

2009 ◽  
Author(s):  
Yoshihiko Kanda ◽  
Kunihiro Zama ◽  
Yoshiharu Kariya ◽  
Takao Mikami ◽  
Takaya Kobayashi ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Reliability Analysis ◽  
Flip Chip ◽  
Cooling Process ◽  
Thermal Cycling Condition ◽  
Solder Bumps ◽  
The Difference ◽  
Analytical Result ◽  
Underfill Material ◽  
Cycling Condition

The effect of viscoelasticity of underfill on the reliability analysis of flip-chip package by using FEA has been investigated in this study. The analytical result on thermal warpage of a package is different depending on whether the underfill is assumed to be elastic or viscoelastic. The difference is prominent in materials with low Tg, specifically during the cooling process. The viscoelastic effect of the underfill on the fatigue life of the solder bumps is also appears in materials with low Tg, and the predicted fatigue life of a package is about twice as short if the underfill is assumed to be elastic instead of viscoelastic. Thus, the differences in the assumption regarding the viscoelastic properties of the underfill affect the reliability analysis of the packages under thermal cycling condition using FEA.

Micromechanics-based thermal expansion characterization of SiC nanoparticle-reinforced metal matrix nanocomposites

2018 ◽  
Vol 233 (1) ◽  
pp. 190-201 ◽  
Author(s):  
Mohammad K Hassanzadeh-Aghdam
Keyword(s):  
Thermal Expansion ◽  
Metal Matrix ◽  
Volume Fraction ◽  
Coefficient Of Thermal Expansion ◽  
Critical Parameters ◽  
Sic Nanoparticles ◽  
Metal Matrix Nanocomposites ◽  
Interphase Region ◽  
Matrix Nanocomposites ◽  
Al Matrix

Understanding the structure–property relations for metal matrix nanocomposites reinforced with nanoparticles is a key factor for a reliable and optimal design of such new material systems. In the present study, coefficient of thermal expansion of silicon carbide (SiC) nanoparticle-reinforced aluminum (Al) matrix nanocomposites is predicted using a three-dimensional unit cell based micromechanical approach. The model takes into account the aluminum carbide (Al4C3) interphase region formed due to the reaction between SiC nanoparticles and surrounding Al matrix. The effects of some critical parameters, including volume fraction and diameter of SiC nanoparticles, interphase features such as geometry and material properties on the coefficient of thermal expansion of Al nanocomposite are extensively investigated. The obtained results clearly reveal the high influence of the interphase region on the coefficient of thermal expansion of Al nanocomposite. Based on the simulation results, the coefficient of thermal expansion of Al nanocomposite nonlinearly decreases with the increase in the interphase thickness or decreasing SiC nanoparticles diameter. Furthermore, the role of interphase in the thermal expansion behavior of Al nanocomposite becomes more prominent with the reduction in the nanoparticle diameter. Also, the coefficient of thermal expansion of Al nanocomposite linearly decreases as SiC nanoparticle volume fraction increases.

Transient and Residual Stresses and Displacements in Self-Curing Bone Cement—Part I: Characterization of Relevant Volumetric Behavior of Bone Cement

1982 ◽  
Vol 104 (1) ◽  
pp. 21-27 ◽  
Author(s):  
A. M. Ahmed ◽  
W. Pak ◽  
D. L. Burke ◽  
J. Miller
Keyword(s):  
Thermal Expansion ◽  
Residual Stresses ◽  
Bone Cement ◽  
Coefficient Of Thermal Expansion ◽  
Stress Generation ◽  
Curing Process ◽  
Cooling Phase ◽  
Volumetric Behavior ◽  
Fixation System

In this first part of a two-part report, some aspects of the volumetric behavior of bone cement during its curing process are examined as a prelude to an analysis for the transient and residual stresses and displacements in stem fixation systems. Experiments show that stress generation in the cement is associated with its temperature while curing and that during the cooling phase, the stresses are mainly due to thermal as opposed to bulk shrinkage. The appropriate coefficient of thermal expansion of bone cement has been evaluated from measurements in a simulated fixation system in conjunction with a thermoelastic analysis.

Sign in / Sign up

Export Citation Format

Share Document