Board Level Reliability of Solid State Camera Modules

摘要

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 packaged silicon die at the heart of each solid state camera module 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 next 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. However resolution is increasing faster than smaller pixels and technology nodes are being introduced. The net result is imager die in micro ball grid array, chip scale packages, are now broaching the 5mm × 5mm boundary beyond which direct attachment to a printed circuit board is not possible. The second part of this paper will present a practical strategy that can be adopted to enable physically large imager die to meet board level reliability Standards.