Description
The field of printed electronics is a rapidly-emerging area of research and development primarily concerned with low-cost fabrication materials and processes for electronic devices. As conventional silicon-based electronic devices continue to push the physical boundaries of scaling to achieve increased performance for electronic devices, the field of printed electronics instead has focused on niche applications where form, function and cost are more important. However, certain applications in the realm of printed electronics are still poised for adoption to industrial processes, namely the application of printed conductors for electrical interconnects.
This work emphasizes this point by exploring different metal systems that can be used to replace eutectic solders in the modern packaging of electronic devices. The first chapter begins with a discussion of the current packaging process and provides a motivation for the need to replace solder with metallic copper in those systems. The chapter ends with an introduction to the different printing processes used throughout this work and their advantage in achieving high performance electrical interconnects. The next three chapters explore different copper systems that could potentially be used as replacement for solder in modern packages. Each of those chapters explain the synthesis process and then later delve into the details of the ink formulation process for the printed technology used. Finally, they end with an electrical and mechanical characterization of the printed features.
The last chapter in this thesis deals with the understanding of the nature of nanoparticle growth upon sintering. The chapter begins with a discussion of the different growth mechanisms involved in nanoparticle systems and their consequences on the overall morphology of the sintered films. It then relates these changes to the differences in the mechanical strengths observed in these films. Finally, the chapter ends with an explanation for these morphological differences and provides a route for using sintering profile as a control knob to tune the mechanical properties of nanoparticle systems.