Room temperature bonding for packaging CMOS image sensors; direct sapphire ceramic sealing

In this paper, we demonstrated the use of a novel bonding technology to manufacture sapphire-ceramic package for CMOS image sensor devices. The package must be reliable enough to be used in the space science missions: it must provide protection from external environment during on-ground testing, storage and use. Environmental and hermeticity tests were performed to evaluate the package quality. Especially the moisture inside the package was observed since it could interrupt the function of an image sensor. Robust packages are also needed in other applications such as medical implants, military and telecoms. The study showed that presented bonding technology can be applied for bonding sapphire to ceramic. Moisture levels of only one tenth of what is commonly detected in the stressed image sensor packages were detected in the manufactured packages. It was shown that package design is robust and varying environmental conditions have no influence on the bonding seams or the device functionality.