Fatigue Test Method for Observing the Delamination Effect in a QFN Package

Semiconductor devices are assembled in a variety of package configurations, and are they used in various applications. The quad flat no lead (QFN) package is useful for improving the reliability of the package. Generally, thermal cycle tests (TCTs) are applied to under development electronic packages in order to prove their reliability. At the early stage, however, a more effective test is desirable because of the TCTs are time-consuming. A new mechanical fatigue test for the QFN package, namely the three-point assembly fixture with a rounded contact surface test method, was proposed and it is the subject of this paper. This fixture 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; a micro tensile tester incorporating a deflection measuring device shall be used to generate a controlled board deflection rate. The validity of the mechanical test method can then be verified based on the stress analysis results and also these obtain in the experiments. Considering the QFN package delamination, lead cracking, package body cracking, and cracking between the various lead statistically based on the experimental, it was shown that the probability during cycle loads and the maximum load for the QFN package for delamination can be estimated.