Method to Improve Die-Attach for Stacked Packages
Original Publication Date: 2004-Oct-25
Included in the Prior Art Database: 2004-Oct-25
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In the current assembly process of stacked FBGA (Fine Pitch Ball Grid Array) packages, there is a contamination of the re-distribution layer (RDL) of the bottom chip during the spacer die-attach step. Due to the capillary effect of the RDL topography, the die-attach glue flows between the RDL traces and prevent mold compound adhesion between the RDL traces as seen in figure 1. In order to avoid the bleed-out of the die attach glue, a special design of the RDL coverage is proposed (figure 2). The RDL coverage features a glue trap that confines the die-attach glue in the vicinity of the spacer.