Here is the abstract you requested from the IMAPS_2007d 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.
|Board Level Reliability of Solid State Camera Modules|
|Keywords: CMOS imager, Camera module, Reliability|
|In common with most semiconductor devices, solid state camera modules are required to meet reliability standards before the product is deemed to be of sufficient quality for commercial release. The primary application for solid state camera modules is in portable electronics, principally mobile phones. Typically more than two million CMOS imagers are manufactured every day of the year solely for this application and predictions suggest that this volume will double by 2009. The packaged silicon die at the heart of each solid state imager are assessed against Standard tests but, surprisingly, there are no industry Standards for complete camera modules. Although the camera module manufacturers subject components to their own internal evaluations the picture is further confused because some of these tests are conducted with the lens train in place and others without. The first part of this paper will review camera module test regimes in use today with particular emphasis on whether the lens train should be present. Proposed is a bare minimum specification that current generation camera modules would be expected to pass for use in mobile phones. The trend in solid state imagers is towards ever higher resolution devices and smaller pixel dimensions. Whereas the first camera phones supported VGA resolution imagers, 2Mpixel is now common and the norm will likely be >3Mpixel in 2008. At the same time the pixel size has only declined from 3um to 1.75um. The net result is that the physical size of camera modules is increasing and imager die are now broaching the 5mmx5mm size beyond which direct attachment to a PCB is not possible. The second part of this paper will evaluate failure mechanisms specific to packaged solid state imagers and present results of some practical strategies that can be adopted to enable physically large imager die to meet board level reliability standards.|
|Dr. Giles Humpston, Director, R&D
San Jose, CA