Toufiq Rahman | Bangladesh University of Engineering & Technology (original) (raw)
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Papers by Toufiq Rahman
The modern trend is to decrease the size of microprocessor components. At the same time, the numb... more The modern trend is to decrease the size of microprocessor components. At the same time, the number of I/O of the silicon chip microprocessors have been greatly increased over the last few years, which means high BUS speed, high amount of heat generation and much more elevated temperature operation. Plastic ball grid array (PBGA) is one of the most widely used microprocessor components in electronic packaging industries. Due to the complex nature of the geometric configuration of the package, thermal stresses are developed inside the package which is the result of package temperature fluctuation. Also thermal stresses may develop when exposed to harsh environments where fluctuation of temperature may occur e.g. spaceship, automobile etc. As a result, the solder balls of PGBA may fail resulting in disconnection of signal to the processor. In our study, the microscopic view of cross section of some PGBA packages were observed. It was found that the copper layer thicknesses of substrates vary from package to package which causes the variation in mechanical properties of the Bismaleimide-Triazine (BT) substrate material. Results show that the variation of mechanical properties of the substrate layer in the microprocessor package significantly affects the thermal cycling life of lead free solder joints which means the number of cycles before failure of the package.
The modern trend is to decrease the size of microprocessor components. At the same time, the numb... more The modern trend is to decrease the size of microprocessor components. At the same time, the number of I/O of the silicon chip microprocessors have been greatly increased over the last few years, which means high BUS speed, high amount of heat generation and much more elevated temperature operation. Plastic ball grid array (PBGA) is one of the most widely used microprocessor components in electronic packaging industries. Due to the complex nature of the geometric configuration of the package, thermal stresses are developed inside the package which is the result of package temperature fluctuation. Also thermal stresses may develop when exposed to harsh environments where fluctuation of temperature may occur e.g. spaceship, automobile etc. As a result, the solder balls of PGBA may fail resulting in disconnection of signal to the processor. In our study, the microscopic view of cross section of some PGBA packages were observed. It was found that the copper layer thicknesses of substrates vary from package to package which causes the variation in mechanical properties of the Bismaleimide-Triazine (BT) substrate material. Results show that the variation of mechanical properties of the substrate layer in the microprocessor package significantly affects the thermal cycling life of lead free solder joints which means the number of cycles before failure of the package.