Flexible and ultra-thin embedded chip package

Abstract

An ultra-thin, flexible package was successfully demonstrated in this paper. The integration of semiconductor chip and flexible substrate, development of ultra-thin chip technology, and embedded chip technology are the key topics. For the purpose of bendable, the embedded chip should be thin enough. The chips were thinned to less than 20µm by mechanical grinding and plasma treatment process. Besides, the dicing before grinding (DBG) method was applied for segment of ultra-thin chips. The ultra-thin chip can be embedded into a thin polyimide material by lamination process and build-up layer coating without die attached film (DAF). Following, micro-via drilling process, metallization and patterning process realize electrical interconnections. A temporary rigid carrier substrate was used for handling ultrathin substrate during process. Finally, an ultra-thin, flexible package was accomplished by releasing from the carrier substrate. Using this novel process, the total thickness of flexible package is only 59µm. It can be easily bended, and the curvature radius of flexible package can reach 10mm without any cracks occurred. The static and dynamic bending tests were also done. The results show this ultra-thin and flexible package has good mechanical properties. Technologies and bending test results will be represented in this paper.