Thin quad flat package with no leads (qfn) fabrication methods

Abstract

Embodiments of the present invention include a method of packaging semiconductor devices. The method comprises the steps of molding a surface of a wafer, sawing the wafer into individual devices, attaching the individual semiconductor device to an adhesive surface, molding the exposed surface, and sawing the wafer into individual semiconductor devices. The step of molding forms a continuous molded layer. The step of sawing results in each individual semiconductor having a molded layer. This molded layer corresponds to a portion of the continuous molded layer. The step of attaching includes attaching the molded layer of the individual semiconductor devices to the adhesive surface. The step of molding the exposed area includes molding an exposed area above the adhesive surface. This forms a solid expanse of material. The step of sawing the wafer into individual semiconductor devices includes sawing the solid expanse of material.

1 . A method of packaging semiconductor devices comprising:
 molding a first surface of a wafer with a first mold compound, and in accordance therewith, forming a continuous molded layer;   sawing the wafer into individual semiconductor devices, each individual semiconductor device includes a molded layer corresponding to a portion of the continuous molded layer;   attaching a surface of each of the molded layers of each of the individual semiconductor devices to an adhesive surface;   molding an exposed area above the adhesive surface with a second mold compound, and in accordance therewith, forming a solid expanse of material;   removing the adhesive surface to expose each of the surfaces of each of the molded layers of each of the individual semiconductor device; and   sawing the solid expanse of material, and in accordance therewith, forming a plurality of individual packaged semiconductor devices.   
     
     
         2 . The method of  claim 1 , wherein the adhesive surface has a leadframe attached thereto and the step of attaching the surface of each of the molded layers of each the individual semiconductor devices to the adhesive surface includes placing the individual semiconductor devices in individual cavities of the leadframe. 
     
     
         3 . The method of  claim 1 , further comprising attaching a bond wire between a conductive pad of each of the individual semiconductor device to a conductive surface of a portion of a leadframe, the conductive surface corresponding to the conductive pad,
 wherein the leadframe and the surface of each the molded layers of the each of the individual semiconductor devices are attached to the adhesive surface.   
     
     
         4 . The method of  claim 1 , wherein the step of molding an exposed area above the adhesive surface includes molding exposed areas of the individual semiconductor devices and a leadframe, and wherein a portion of the leadframe and a portion of the surface of each of the molded layers of each of the individual semiconductor devices are attached to the adhesive surface, and in accordance therewith, said attached portions remain unexposed. 
     
     
         5 . The method of  claim 4 , wherein the step of molding an exposed area above the adhesive surface includes molding bond wires between conductive pads of each of the individual semiconductor devices and the leadframe. 
     
     
         6 . The method of  claim 1 , wherein the first mold compound is the same as the second mold compound. 
     
     
         7 . The method of  claim 1 , wherein portions of the second mold compound meld with portions of the first mold compound. 
     
     
         8 . The method of  claim 1 , wherein portions of the second mold compound adhere with portions of the first mold compound. 
     
     
         9 . The method of  claim 1 , wherein the step of sawing the solid expanse of material includes sawing the leadframe. 
     
     
         10 . The method of  claim 8 , wherein the step of sawing the solid expanse of material further includes sawing the second mold compound overlying the leadframe.