Microscopic observation of failure mechanism of anisotropic conductive film for flip-chip joining

The objective of this work was to study the failure mechanism of anisotropic conductive film (ACF) in chip-on-glass (COG) by microscopic observation. A semiconductor thermal cycle system was designed and manufactured based on the mechanism that a semiconductor P-N joint was able to generate cool and hot with electric current variation. The device took less than 40 min to complete a thermal cycle from -40/spl deg/C to 95/spl deg/C. An on-site local microscopic observation system was set up with an electron microscope. The moisture absorption of foil-on-glass (FOG) specimens were measured under thermal cycling (-40/spl deg/C to 95/spl deg/C ), high temperature and high humidity (85/spl deg/C, 85%RH), and the ambient air (20/spl deg/C, 41%RH) conditions, respectively. The evolution of interfacial bubbles and delamination of COG specimens was observed. The experiment has shown that the moisture absorption of ACF in FOG varied with the temperature and humidity.