Here is the abstract you requested from the IMAPS_2007 technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|Effect of Moisture on Dielectric Properties of CSP Board-Level Underfill|
|Keywords: Underfill, Moisture Resistance, Dielectric Properties|
|Using accelerated aging conditions to predict the reliability of a device is standard practice in the electronics world. Accelerated aging specifications are driven by the end use application and life expectancy of the device. OEMs supplying portable devices commonly require drop resistance, thermal cycling stability, and long term electrical stability. With each generation, OEMs are increasing the device level reliability requirements to reflect the consumer’s on-the-go lifestyle. Since the early 1990’s, OEMs have successfully employed underfill adhesives to achieve the desired mechanical integrity. Recently, OEMs have been implementing more challenging conditions to so-called “damp heat” accelerated aging tests. Underfills are expected to exhibit minimal moisture ingress and retain their functionality in the device. This paper will assess the changes in an underfill’s dielectric properties as a function of residence time at 85*C/85%RH. Ionic mobility data and surface insulation resistance will be compared with changes in volume resistivity and permittivity as a function of moisture uptake. Additionally, drop impact performance will be correlated to changes in bulk mechanical properties (Tg, E’, E”) and adhesion strength, and this will demonstrate the need for low moisture uptake underfills.|
|Andrew Collins, Principal Chemist New Product Development
Emerson & Cuming