Reflow of thermoplastic sheet for passivation of power integrated circuits

A method comprising:

• (a) placing a sheet of material over wirebonds and a semiconductor die, wherein the die is attached to a substrate, wherein the wirebonds are attached to the semiconductor die, and wherein the sheet of material comprises a layer of PET poly(ethylene terephthalate);
• (b) heating the sheet of material such that the sheet of material softens and becomes conformal to the wirebonds and to the semiconductor die, wherein the conformal sheet of material directly contacts the wirebonds and the semiconductor die;
• and
• (c) overmolding the semiconductor die, the wirebonds, the conformal sheet of material, and at least a part of the substrate in a resin encapsulant material, wherein the resin encapsulant material contacts the conformal sheet of material.

A packaged semiconductor device comprising:

• a substrate;
• a semiconductor die attached to the substrate, wherein the semiconductor die has sidewalls;
• a wirebond attached to the semiconductor die;
• an amount of resin encapsulant that forms an outside surface of the packaged semiconductor device, wherein the outside surface extends over the semiconductor die;
• and
• means for conformally covering the semiconductor die, the wirebond, and a portion of the substrate with a layer of reflowed thermoplastic sheeting such that the reflowed thermoplastic sheeting is disposed between the semiconductor die and the amount of resin encapsulant, and wherein the means directly contacts the sidewalls of the semiconductor die, the wirebond, and the portion of the substrate.

A packaged multi-chip power module, comprising:

• a substrate;
• a plurality of power semiconductor dice attached to the substrate;
• a wirebond attached to at least one of the dice;
• a sheet of material that extends over the dice, the wirebond, and at least part of the substrate, wherein the sheet of material is substantially conformal to the wirebond and to the dice and directly contacts the wirebond and the dice, wherein the sheet of material comprises a layer of PET (poly(ethylene terephthalate));
• and
• a housing that houses the substrate, the dice, the wirebond, and the sheet of material.

A method comprising:

• (a) placing a sheet of material over wirebonds and a semiconductor die, wherein the die is attached to a substrate, wherein the wirebonds are attached to the semiconductor die, and wherein the sheet of material comprises a layer of PET (poly(ethylene terephthalate));
• (b) heating the sheet of material such that the sheet of material softens and becomes conformal to the wirebonds and to the semiconductor die thereby forming a PET-coated substrate assembly, wherein the conformal sheet of material directly contacts the wirebonds and the semiconductor die of the PET-coated substrate assembly;
• and
• (c) incorporating the PET-coated substrate assembly into a power module.