"To meet the urgent market demand for small package size and high reliability performance for automotive CMOS image sensor (CIS) application, wafer level chip scale packaging (WLCSP) technology using through silicon vias (TSV) needs to be developed to replace current chip on board (COB) packages. In this paper, a WLCSP with the size of 5.82 mm × 5.22 mm and thickness of 850 μm was developed for the backside illumination (BSI) CIS chip using a 65 nm node with a size of 5.8 mm × 5.2 mm. The packaged product has 1392 × 976 pixels and a resolution of up to 60 frames per second with more than 120 dB dynamic range. The structure of the 3D package was designed and the key fabrication processes on a 12” inch wafer were investigated. More than 98% yield and excellent optical performance of the CIS package was achieved after process optimization. The final packages were qualified by AEC-Q100 Grade 2."
This is an interesting topic : RELIABILITY. Here a reliable wafer level packaging technique is announced, but I do have to make the remark that ABSOLUTELY not all existing sensors and/or cameras are reliable and ready for the harsh environments of the automotive world. I have been testing and testing devices of several vendors at 85% humidity and 85% degr.C. and you don't believe your own eyes if you see the results. Because an awfull lot of work has been put into these experiments, I cannot reveal the data or give you hard numbers. But the reliability reports are available for sale. Next to 85/85 tests, also stress by means of sunlight is evaluated as well as cosmic ray damage.
ReplyDeleteOne thing is for sure : CMOS sensors are much more reliable than CCDs ever were, but also CMOS degrades over time !