Flexible electronic circuits with embedded integrated circuit die and methods of making and using the same

Abstract

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.

1 - 14 . (canceled) 
     
     
         15 . A method for assembling a flexible circuit (IC) module, the method
 comprising:
 providing first and second flexible substrates, each of the flexible substrates including a respective layer of flexible polymer with two layers of conductive material each disposed on a respective side of the layer of flexible polymer; 
 attaching a semiconductor die to the second flexible substrate; 
 laminating an encapsulating layer to the first flexible substrate, the encapsulating layer including a thermoplastic resin or a polyimide adhesive, or both; and 
 laminating the encapsulating layer and the first flexible substrate to the second flexible substrate such that the thermoplastic resin or the polyimide adhesive, or both, flow around and encase therein the semiconductor die. 
   
     
     
         16 . The method of  claim 15 , further comprising patterning circuitry on one or more of the layers of conductive material of the first and second flexible substrates. 
     
     
         17 . The method of  claim 15 , further comprising laser drilling one or more vias through the first flexible substrate to the semiconductor die. 
     
     
         18 . The method of  claim 17 , further comprising electroplating the one or more vias to connect the first flexible substrate to the semiconductor die. 
     
     
         19 . The method of  claim 15 , wherein the encapsulating layer is the polyimide adhesive, the polyimide adhesive comprising an acrylic-based thermally conductive and electrically isolating polyimide adhesive. 
     
     
         20 . The method of  claim 15 , wherein the encapsulating layer is the thermoplastic resin, the thermoplastic resin comprising a B-stage FR-4 glass-reinforced epoxy thermoplastic polymer or copolymer or blend.