| Due to the advantages of large input/output capacity and the ability to improve the electrical performance,the flip chip technology is widely used in the semiconductor packaging industry.The underfill is an important process in flip chip packaging,and the most common underfill process is the capillary-force-driving underfill process.It is important to study the flow behavior of encapsulated materials in the process of underfill for actual underfill packaging production.In this paper,the flow behavior of the underfill fluid was studied through experiments,which emphasized on the size of solder bumps,the width between solder bumps and the way of filling.And the accuracy of the two-dimensional numerical analysis method was verified according to the experiment results.The main researches and results are as following:(1)The photolithography technology was used to produce experiment samples,the substrates and chips were replaced by transparent glass plates,the solder bumps were acquired by etching the silicon which were on the surface of glass plates.The three were fabricated together by SOG(Silicon on Glass)technology,which achieved the visualization of the flow process.(2)The visualized experiment platform of the underfill flow was set up.The influence of diameter of solder bumps?the width between solder bumps and the filling type to underfill process were studied by comparing the experiment results of thirteen groups.(3)For the experimental cases,the two-dimensional simulation method was used to simulate the underfill flow process,and the accuracy of the method was verified by comparing the simulation results and experiment results.Furthermore,the deviations between experiment and simulation were analyzed.(4)The two-dimensional simulation analysis method was applied to a flip chip from IBM.The accuracy was tested by experiments,which showed that the two-dimensional numerical analysis method has high practical value. |
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