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Full-Text Articles in Engineering
Column-Grid-Array (Cga) Versus Ball-Grid-Array (Bga): Boardlevel Drop Test And The Expected Dynamic Stress In The Solder Material, Ephraim Suhir, Reza Ghaffarian
Column-Grid-Array (Cga) Versus Ball-Grid-Array (Bga): Boardlevel Drop Test And The Expected Dynamic Stress In The Solder Material, Ephraim Suhir, Reza Ghaffarian
Mechanical and Materials Engineering Faculty Publications and Presentations
Board level drop test is considered with an objective to develop a physically meaningful analytical predictive model for the evaluation of the expected impactinduced dynamic stresses in the solder material. Ball-gridarray (BGA) and column-grid-array (CGA) designs are addressed. Intuitively it is felt that while the application of the CGA technology to relieve thermal stresses in the solder material might be quite effective (owing to the greater interfacial compliance of the CGA in comparison with the BGA), the situation might be quite different when the PCB/package experiences dynamic loading. This is because the mass of the CGA joints exceeds considerably that …
Predicted Stresses In Ball-Grid-Array (Bga) And Column-Grid-Array (Cga) Interconnections In A Mirror-Like Package Design, Ephraim Suhir, Reza Ghaffarian, Johann Nicolics
Predicted Stresses In Ball-Grid-Array (Bga) And Column-Grid-Array (Cga) Interconnections In A Mirror-Like Package Design, Ephraim Suhir, Reza Ghaffarian, Johann Nicolics
Mechanical and Materials Engineering Faculty Publications and Presentations
There is an obvious incentive for using bow-free (temperature change insensitive) assemblies in various areas of engineering, including electron device and electronic packaging fields. The induced stresses in a bow-free assembly could be, however, rather high, considerably higher than in an assembly, whose bow is not restricted. The simplest and trivial case of a bow-free assembly is a tri-component body, in which the inner component is sandwiched between two identical outer components (“mirror” structure), is addressed in our analysis, and a simple and physically meaningful analytical stress model is suggested. It is concluded that if acceptable stresses (below yield stress …
Could Application Of Column-Grid-Array (Cga) Technology Result In Inelastic-Strain-Free State-Of-Stress In Solder Material?, Ephraim Suhir, Reza Ghaffarian, Johann Nicolics
Could Application Of Column-Grid-Array (Cga) Technology Result In Inelastic-Strain-Free State-Of-Stress In Solder Material?, Ephraim Suhir, Reza Ghaffarian, Johann Nicolics
Mechanical and Materials Engineering Faculty Publications and Presentations
Physically meaningful and easy-to-use analytical stress model is developed for a short cylinder (beam) clamped at the ends and subjected to bending caused by the ends offset. The offset is due, in its turn, to an external lateral force that has to be determined from the known offset. It is envisioned that such a beam can adequately represent the state of stress in a column-grid-array (CGA) solder joint interconnection experiencing thermal loading due to the thermal expansion/contraction mismatch of the IC package and the printed circuit board (PCB). The CGA designs are characterized by considerably higher stand-off heights than ball-grid-array …
Predicted Stresses In A Ball-Grid-Array (Bga)/Column-Grid-Array (Cga) Assembly With A Low Modulus Solder At Its Ends, Ephraim Suhir, Reza Ghaffarian
Predicted Stresses In A Ball-Grid-Array (Bga)/Column-Grid-Array (Cga) Assembly With A Low Modulus Solder At Its Ends, Ephraim Suhir, Reza Ghaffarian
Mechanical and Materials Engineering Faculty Publications and Presentations
A simple, easy-to-use and physically meaningful predictive model is suggested for the assessment of thermal stresses in a ball-grid-array or a column-grid-array with a low modulus solder material at the peripheral portions of the assembly. It is shown that the application of such a design can lead to a considerable relief in the interfacial stresses, even to an extent that inelastic strains in the solder joints could be avoided. If this happens, the fatigue strength of the bond and of the assembly as a whole will be improved dramatically: low-cycle fatigue conditions will be replaced by the elastic fatigue condition, …