The Realization of Redistribution Layers for FOWLP by Inkjet Printing

Abstract

The implementation of additive manufacturing technology (e.g., digital printing) to the electronic packaging segment has recently received increasing attention. In almost all types of Fan-out wafer level packaging (FOWLP), redistribution layers (RDLs) are formed by a combination of photolithography, sputtering and plating process. Alternatively, in this study, inkjet-printed RDLs were introduced for FOWLP. In contrast to a subtractive method (e.g., photolithography), additive manufacturing techniques allow depositing the material only where it is desired. In the current study, RDL structures for different embedded modules were realized by inkjet printing and further characterized by electrical examinations. It was proposed that a digital printing process can be a more efficient and lower-cost solution especially for rapid prototyping of RDLs, since several production steps will be skipped, less material will be wasted and the supply chain will be shortened.

Classifications and Applications of Inkjet Printing Technology: A Review

“…Two commercialized printheads, i.e., piezoelectric and EHD, were used for printing metals and polymers [244]. Roshanghias et al [245] inkjet-printed redistribution layers (RDLs) and a metal route used to connect the MEMS microphone pads to application-specific integrated circuits (ASICs) and fan-out the signals via solder balls. In another study, they inkjet-printed the RDLs of Ag-ink nanoparticles for the fan-out packaging of capacitive micromachined ultrasound transducers [246].…”

Single-Step Direct Growth of Graphene on Cu Ink toward Flexible Hybrid Electronic Applications by Plasma-Enhanced Chemical Vapor Deposition

“…Specifically, additive manufacturing such as IJP is promising to greatly lower production costs because of its superior material utilization efficiency by direct patterning and its scalability. , IJP has been successfully demonstrated in devices such as printed sensors, − antennas, , interconnects, , and displays. , However, the high surface-to-volume ratio of the metallic nanoparticles in the ink material is susceptible to rapid oxidation. Therefore, substantial emphasis has been made on silver ink because of its resistance to oxidation and the conductive nature of its oxidized surface layer .…”

On the Feasibility of Fan-Out Wafer-Level Packaging of Capacitive Micromachined Ultrasound Transducers (CMUT) by Using Inkjet-Printed Redistribution Layers

“…As schematically illustrated in Figure 1 , metallic and dielectric structures can be deposited selectively and in a controlled volume via a drop-on-demand printing technology (e.g., inkjet, aerosol, electrostatic, electrohydrodynamic, etc.). The concept of inkjet-printed RDLs for FOWLP was introduced in our previous work [ 11 ]. Inkjet-printed circuitry was also evaluated for the fabrication of low-cost silicon [ 12 ] and organic interposers [ 13 ], which showed great potential for rapid prototyping and signal probing.…”