US Patent 9899330 Flexible electronic circuits with embedded integrated circuit die

Flexible integrated circuit (IC) modules, flexible IC devices, and methods of making and using flexible IC modules are presented herein. A flexible integrated circuit module is disclosed which includes a flexible substrate and a semiconductor die attached to the flexible substrate. An encapsulating layer, which is attached to the flexible substrate, includes a thermoplastic resin and/or a polyimide adhesive encasing therein the semiconductor die. The encapsulating layer may be an acrylic-based thermally conductive and electrically isolating polyimide adhesive. Optionally, the encapsulating layer may be a B-stage FR-4 glass-reinforced epoxy thermoplastic polymer or copolymer or blend. The die may be embedded between two flexible substrates, each of which includes a layer of flexible polymer, such as a polyimide sheet, with two layers of conductive material, such as copper cladding, disposed on opposing sides of the layer of flexible polymer.