Papers by Keyword: QFN

Abstract: Quad Flat No-Lead or QFN is able to provide lighter, thinner and higher performance packaging requirement with its exposed pad and leads at the package bottom for better heat dissipation. However, QFN packages possess certain weaknesses. QFN package failures are related to crack and delaminating, such as die cracking, moulding compound and solder mask interfacial delaminating. From previous projects, the epoxy thickness and die thickness plays an important role in reducing failures in QFN package. The objective of this project is to observe the effects of die and epoxy thickness. The effects on QFN are measured in the die and lead frame part. Stress towards the die is also measured: including thermal, first principle and Von Misses stress. The structural optimization is based on the Finite Element Analysis (FEA). By using ANSYS 10.0, six models were constructed, where three models were built to analyse in thickness of epoxy, and another three to study the effects on die thickness. The effect was measured by the value stress (first principle stress and Von Misses stress) and thermal strain effect, which will lead to a result of how the dimensions of the packaging will give a better tolerance towards stress.

Abstract: This paper presents a methodology to determine the durability of Quad Flat No-Lead (QFN) package. The QFN package is useful for improving the reliability of the package. A mechanical fatigue test namely three points bending cyclic test and signal analysis were proposed in this paper. The three points bending cyclic test method is a test assembly that supports a specimen on two anvils or rollers, and symmetrically loads the specimen on the opposite surface with an anvil or roller using micro-tester machine. For strain signal collection, a strain gauge was connected to the dynamic data acquisition system, and it was used for each tested QFN package for determining the response of the captured cyclic strain signal. It was found that the sinusoidal amplitude pattern of signal response has been obtained during the constant three points bending cyclic test. The obtained response signals were then analysed using the Power Spectral Density.

Abstract: This paper discusses some issues in micromechanical property of a newly developed Quad Flat No-lead (QFN) 3D stacked die package using three-point bending test approach. The relevant test methodologies were carried out in order to observe the flexural stress, strain, maximum load and deflection of the package. While performing the test, these QFN packages were positioned on the three points test bench, and the specific applied load was then applied and moved down until the package was clearly bent and broken. The related findings indicated that the maximum load was found to be at 251.52 N and the maximum deflection was obtained at 0.41 mm. The results were important for setting related testing parameters (load, stress and strain) before applying the three point cyclic bending test on the QFN stacked die package as the future work.