3D-stacking of UTCPs as a module miniaturization technology

3D-stacking of Ultra Thin Chip Packages (UTCP’s) – one of the emerging technologies in the field of high density integration - is presented here. This technology is developed to increase the functionality of the electronic devices and to raise the comfort zone by reducing the overall size and weight of the package. This has a bright future in the area of mobile communication, medical equipments like hearing aids, implants, patient monitoring. This paper describes an approach to produce miniaturized modular packages by using Ultrathin Chip Package Technology, stacking and through-hole (TH) interconnection technology. UTCP technology is a board level packaging concept, based on embedding of ultra-thin chips (~20 µm) within two 20 µm thick spin-on polyimide layers resulting in a thin flexible chip package of thickness ~50 µm. Stacking of the 4 layers of UTCPs by using 25 µm thick layers of adhesive films and vacuum lamination processes results in stacked UTCP modules of total thickness ~300 µm. The connection to the different layers of the UTCPs is realized by drilling THs on the outer contact pads on the stacked packages, followed by metallization of these THs by Cu electroless deposition, electroplating and finally metal structuring. After processing and testing, the stacks can be easily mounted within functional demonstrators (e.g, Hearing Aid device, etc) replacing single silicon die of almost same size, but with 4 times output.

Publication year:2011

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