Solder Extrusion Characterization Study on SiP Modules Inductors

Demand for higher levels of integration with cost effective solution have driven the increased use of and innovation in System in Package module for Radio Frequency (RF) new products. System in Package (SiP) module high integration capability allows for wide range of power and frequency applications ranging from low power remote heads to massive Multiple-Input Multiple-Output (MIMO) systems. System in Package module employs both active devices and passive components, such as inductor, capacitor and resistor, together with other materials like substrate, solder and gold wire. This paper discusses the characterization study of solder extrusion during the development work for a new product employing new substrate plating. The study covered two characterization activities on key factors affecting solder extrusion under inductors namely, material characterization and process characterization. Materials characterization covered the study of new substrate plating and the inductor type considered under the new product which may impact solder extrusion. Process Characterization covered the study of solder paste screen print process versus their solder extrusion output response. Characterizations resulted to the definition of optimum pre-mould plasma cleaning parameter and solder screen printing process parameters for the new product, the results of which were integrated in its further development, qualification and production release.