Experimental characterization of adhesion strength between the silicone encapsulant and the bottom of a SMD LED leadframe cup

This paper presents an experimental study on the adhesion strength between the silicone encapsulant and the bottom of the leadframe cup of a 3528 SMD LED. In this study, a new test method was proposed using silicone to mount a piece of dummy silicon chip to the bottom of the leadframe cup. Afterwards, a bond tester was employed to apply the loading on the edge of the dummy silicon chip to shear the silicone underneath. In addition to the characterization of adhesion strength, parametric studies were also performed to investigate the effects of shear height and shear speed on the adhesion strength. Detailed information about sample preparation and experimental procedure will be presented in the paper.