Flexible circuits on soft substrates

A method for manufacturing an electronic device, comprising:

• placing a solid circuit die with one or more contact pads on a first major surface of a substrate such that the one or more contact pads contacts the first major surface of the substrate to provide an at least partially sealed contact pad;
• placing an electrically conductive trace on the first major surface of the substrate, wherein the electrically conductive trace has a first exposed major surface and a second surface, wherein the second surface of the electrically conductive trace contacts the first major surface of the substrate to provide an at least partially sealed electrically conductive trace;
• applying a liquid encapsulant over the first major surface of the substrate and the solid circuit die;
• hardening the liquid encapsulant to form a carrier with a first major surface contacting the first major surface of the substrate and forming an interface therewith;
• separating the carrier and the substrate at the interface to expose:
• (1) the at least partially sealed one or more contact pads on the first major surface of the carrier to provide an at least partially exposed one or more contact pads, and (2) the at least partially sealed electrically conductive trace to provide an at least partially exposed electrically conductive trace surface;
• applying a guide layer on the first major surface of the carrier, wherein the guide layer comprises a microchannel with a first end overlying the at least partially exposed contact pad and a second end overlying the exposed at least partially exposed electrically conductive trace surface;
• depositing a conductive particle-containing liquid in the microchannel to contact the at least partially exposed one or more contact pads and the at least partially exposed electrically conductive trace and form an interconnection therebetween;
• and
• solidifying the conductive particle-containing liquid to form an electrically conductive trace in the microchannel

A method for manufacturing an electronic device, comprising:

• placing a solid circuit die with one or more contact pads on a first major surface of a substrate such that the one or more contact pads contacts the first major surface of the substrate to provide an at least partially sealed contact pad;
• placing an electrically conductive trace on the first major surface of the substrate, wherein the electrically conductive trace has a first exposed major surface and a second surface, wherein the second surface of the electrically conductive trace contacts the first major surface of the substrate to provide an at least partially sealed electrically conductive trace;
• applying a liquid encapsulant over the first major surface of the substrate, the solid circuit die and the electrically conductive trace;
• hardening the liquid encapsulant to form a carrier with a first major surface contacting the first major surface of the substrate and forming an interface therewith;
• separating the carrier and the substrate at the interface to expose:
• (1) the at least partially sealed one or more contact pads on the first major surface of the carrier to provide an at least partially exposed one or more contact pads, and (2) the at least partially sealed electrically conductive trace to provide an at least partially exposed electrically conductive trace surface;
• laminating a guide layer on the first major surface of the carrier, wherein the guide layer comprises a microchannel with a first end overlying the at least partially exposed contact pad and a second end overlying the exposed at least partially exposed electrically conductive trace surface;
• applying a mask layer over the guide layer and the first major surface of the carrier, wherein the microchannel in the guide layer remains exposed;
• vapor depositing a conductive particle-containing liquid on the mask layer and in the microchannel of the guide layer, wherein the conductive particle-containing liquid contacts the at least partially exposed one or more contact pads and the at least partially exposed electrically conductive trace and form an interconnection therebetween;
• solidifying the conductive particle-containing liquid to form an electrically conductive trace in the microchannel;
• and
• removing the mask layer.