Abstract: A polymer lead-frame is made from a flexible substrate with flexible conductive traces. The generally square lead-frame has diagonal cutouts partially extending from the corners towards the center, as well as a central hole that lies within a footprint of the die. The die is bonded directly to the lead frame, preferably with anisotropic, electrically conductive adhesive. The die is placed with the lead frame in a fixture. A holding force is applied to secure the die and, if necessary, a curing force is applied during a cure cycle. The fixture allows transport of the assembly to a curing oven and allows application of the curing force. The die has contact pads characterized by a non-planar, non-bump-like surface with concavities having depths of at least about one-seventh the diameter of conductive particles in the anisotropic conductive adhesive.

Abstract: A method of making a planar, subsurface electronic circuit having at least one electronic circuit component assembled therewith is disclosed. First, three dimensional, essentially square channels interspersed with lands are formed within a dielectric material on a substrate. The channels are then filled in one pass with a curable polymeric material containing a conductive metal filler so that the upper surfaces of the circuit trace formed by this conductive material are at essentially the same level as the upper surface of the lands. Circuit components are place to engage the conductive material. The curable material is then cured after placing the electronic component(s).

Abstract: A polymer lead frame is made from a flexible substrate with flexible conductive traces. The generally square lead frame has diagonal cutouts partially extending from the corners towards the center, as well as a central hole that lies within a footprint of the die. The die is bonded directly to the lead frame, preferably with anisotropic, electrically conductive adhesive. The die is placed with the lead frame in a fixture. A holding force is applied to secure the die and, if necessary, a curing force is applied during a cure cycle. The fixture allows transport of the assembly to a curing oven and allows application of the curing force. The die has contact pads characterized by a non-planar, non-bump-like surface with concavities having depths of at least about one-seventh the diameter of conductive particles in the anisotropic conductive adhesive.