The Semiconductor industry has experienced continued rapid growth due to continuous improvements in the integration density of various electronic components (i.e., transistors, diodes, resistors, capacitors, etc.). For the most part, this improvement in integration density has come from repeated reductions in minimum feature size, which allows more components to be integrated into a given area. Three-dimensional (3D) integrated circuits (ICs) are therefore created to resolve the limitations of the number and length of interconnections between devices as the number of devices increases. Dies-to-wafer stack bonding is one method for forming 3D ICs, wherein one or more die is bonded to a wafer, and the size of dies may be smaller than the size of chips on the wafer. In order to reduce the thickness of semiconductor packages, increase the chip speed, and for high-density fabrication, efforts to reduce the thickness of a semiconductor wafer are in progress. Thickness reduction is performed by so-called backside grinding of a semiconductor wafer on the surface opposite that containing pattern-formed circuitry, on which a carrier is typically attached to support wafer handling through an adhesive material. Because the thinned wafer tends to have insufficient strength and is more susceptible to deformation such as bending and/or warping, a surface of the wafer is then encapsulated in a molding compound (e.g., thermo-curing epoxy resin), prior to the wafer being separated into individual chip packages using a dicing process. However, a portion of the adhesive material adjacent to the wafer edge is exposed, and which is easily attacked in subsequent etching process, e.g., a wet etch or dry etch process, causing a problem of temporary carrier boning and de-bonding processes. Conventionally an edge seal layer is provided on the edge of the adhesive material, but the following wafer thinning process exposes another portion of the adhesive material adjacent to the wafer edge.
USPTO Backgrounds
USPTO Backgrounds