Strip grinding introduction for thin PoP

Abstract

Due to rapid growth in the mobile industry, Package-onPackage (PoP) has been widely adopted for 3D integration of logic and memory devices within mobile handsets, and other portable multimedia products, etc. Typical PoP configuration includes a logic function in the bottom package while memory dice are assembled into the top package. The TMV solution is widely adopted to reduce package warpage, to achieve a fine pitch PoP, and to stabilize stacking performance. Another big benefit of the TMV is to generate a thin structure by exposing the back side of the die using a film assist mold system. However, the trend of mobile devices is going thinner and thinner, and there is a limitation to achieve the thin PoP structure. The most difficult barrier to generate the thin PoP structure is the warpage control. In this paper, a strip grinding process is introduced as a solution to generate thinner PoP structures in overmolded packages. Applying the strip grinding process to exposed die, reducing mold clearance, and exploring double sided mold structures to reduce die/package height were also investigated.

Implementation and Performance Evaluation of a Bivariate Cut-HDMR Metamodel for Semiconductor Packaging Design Problems with a Large Number of Input Variables

“…The details of design variables are summarized in Table 3. The design spaces of the package dimensions and the material properties were defined by the values found in the literature: package dimensions in [31,[33][34][35][36][37][38][39] and material properties in [40][41][42][43][44][45]. The TFBGA package was subjected to the EMC molding process at 175 • C, which was used as a stress-free temperature.…”