Here is the abstract you requested from the Automotive_2012 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.
|Cooling from Down Under – Thermally Conductive Underfill|
|Keywords: thermal management, underfill, reliability|
|The industry trend towards reduced feature size and faster operating speed has generated increased demand for flip chip devices. Flip chip technology enables design flexibility through shorter electrical paths, smaller footprints and form factor, and higher I/O density. Flip chip devices are however susceptible to thermal cycling and mechanical shock stresses and require the use of an underfill to achieve the desired reliability. In addition, despite improvements resulting from advances in the device design, the cooling capabilities of these packages still limit device performance, especially in devices where there is limited space for traditional heat dissipation techniques (i.e.: thermal interface materials combined with a heat sink and/or fan). To address the issue of thermal dissipation in flip chip applications, LORD Corporation has developed a thermally conductive underfill which combines the excellent processing properties and reliability improvement of a traditional underfill with a thermal conductivity of 1.2 W/mK. The thermally conductive underfill is ideal for flip chip applications where there is insufficient space for traditional heat dissipation techniques and/or in hermetic packages in which there is no air flow available to cool the device. This paper describes the key challenges in developing underfill technologies imposed by the package geometries (small gaps and dense area array interconnects) and performance requirements (fast flow and improved reliability performance). These demands on underfills require polymeric materials with improved chemistries and fillers with specially selected size distribution and morphology. We will discuss the design of a non-anhydride underfill with low viscosity, small particle size filler, fast flow and high reliability. These properties are essential in designing underfills to encapsulate small to large die with narrow stand-off heights. Physical properties, processing parameters of the underfill as well as flip chip device reliability data will be presented.|