Reliability Enhancement of ACF Joined Flip Chips with Parylene C as a Protective Coating

Abstract

Electronic devices are entering every field of life nowadays. Also medicine uses electrical instruments and devices every day, and the safety and reliability are the key factors in that sector. Also the operational aspects of devices are of course vital and make the device useful and worth wile. However, the hardware of the device plays also a key role, since w ithout it the programs cannot function. Furthermore, the use of different packaging technologies determines the size and weight of the device. As the devices get more complicated, the packaging of electronics becomes more important. In this study the reliability of anisotropically conductive adhesive joined flip chip components is considered with a parylene C protective coating on top. With this coating the compatibility with human body and the reliability in medical devices are ensured. Reliability testing was made in 8585-constant humidity test with two different test substrate layouts and test chips. These contained thin chip and substrate structure and thick chip and substrate l a y o u t s. T he re s u l t s s ho w t ha t w i t h t h i n , m o re s p a c e saving and lighter structure, the reliability can be dramatically improved. Furthermore, parylene C proves to be an excellent protection against humid environment enhancing the long term reliability even more.