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This paper presents a new numerical model to characterize the compression molding of wafer level packaging with epoxy polymer molding compound. With its successful application on a reconfigured carrier wafer with fully populated 3-die packages embedded, flow pattern in the wafer level compression molding is characterized for various process conditions and 2 different molding compounds. Focuses have been given on die shift induced by the impact of compression mold flow. Flow pattern and flow drag on individual die is presented. If the adhesive force is less than the maximum flow drag on the die during compression molding, die shift will take place. Results show that the peripheral dies experience highest flow drag and thus are more likely to shift outwards. Moreover, higher compression speed at low molding temperature for a low viscosity molding compound increases the risk of die shift. Key advantage of this numerical study is to give the insights into process parameters and provide initial process window to prevent die shift induced by compression flow drag. [ABSTRACT FROM PUBLISHER]

In recent years, embedded wafer level package (EMWLP) technology has become a promising platform for SiP integration [1] due to its relatively low cost and good electrical performance [1–2]. As the platform is being considered for higher frequency applications (eg. 77-GHz radar), it becomes pertinent to characterize for the dielectric properties of the materials involved. Another concern is that the dielectric properties of inhomogeneous materials (eg. mold compound) may vary from batch to batch. Thus, it is desirable to have structures which are compact to enable in-situ dielectric characterization. In this work, we propose meander T-resonator structure for in-situ dielectric characterization. We also attempt to extract for the relative permittivity of the mold compound in a coplanar waveguide (CPW) configuration, based on analytical expressions. Lastly, we compare the results extracted from both the T-resonator and transmission line (TL) structure. [ABSTRACT FROM PUBLISHER]