Novel methodology to integrate ultra-thin chips on flexible foils

The placement and integration of ultra-thin chips (UTCs) on low-cost polymer foils is a key challenge in the realization of large-area flexible electronic products. Such products, are for cost reasons, preferably fabricated on low cost polyester foils like PET/PEN. A disadvantage of these materials is that they have a low thermal stability. As a consequence of this, the majority of existing chip integration technologies cannot be used. A novel approach for placement and interconnection of UTCs is presented in this paper. This approach, which involves face-up bonding of UTC and its subsequent interconnection, is compatible with low-cost polymer foils. The key process steps involved in UTC integration using the proposed methodology are discussed in detail. The fabrication of a technology demonstrator to validate the proposed concept is also detailed.