Molded Substrates for Inkjet Printed Modules

Ever increasing demand for high-performance, miniaturized, low-cost, and more environmentally conscious targets set high requirements for electronics packaging and manufacturing. Digital drop-on-demand printing of materials is an interesting approach for electronics manufacturing allowing several advantages compared to subtractive methods to manufacture electronics. Additive processing by means of digital printing offers new possibilities to electronics integration, by enabling direct writing on even nonplanar surfaces, and interconnection without specific substrate for components. A module utilizing additive deposition of conductive metallic nanoparticle inks and dielectrics using inkjet printing was designed. Conventional laminate-based or ceramic interconnection substrate, i.e., printed wiring boards was not used as often in electronics modules. Chip-first modules made using a particular encapsulation method were constructed of molded substrate with embedded components and without any wiring. The molding process and the characteristics of molding material were examined using real product samples, material characterization methods, and modeling. The interconnection process using inkjettable metallic nanoparticle and dielectric inks set strict requirements for molding materials; the surface characteristics should be suitable for the inkjetting of conductive and dielectric materials. Additionally, material must withstand the harsh process conditions that include several heating cycles in relatively high temperatures for organic materials. The surface characteristics of the molding material should be adjusted to ensure good control of inkjetted fluids on a surface enabling high-yield inkjetting of fine-pitch patterns. Furthermore, the mechanical properties of molding material and molding material surface have an effect on the interconnection process yield and reliability of the inkjetted lines and interconnections. The characteristics of molded modules working as substrate for additively processed patterns is a crucial role in the manufacturing of a highly integrated printed module.