New Opportunities in Metallization Integration in Cofired Electroceramic Multilayers by the Cold Sintering Process

Metallization with high conductivities is critical in the design of high performance multilayer electroceramic devices. Cold sintering offers exciting new opportunities in the integration of different material classes; here we explore novel metal chemistries and demonstrate their integration into ceramic multilayers. The processing is enabled due to the cosintering of both the ceramic and metal powders in fast times and at extremely low sintering temperatures. Metal powders are printed as pastes and formed into multilayers that can be cosintered with the ceramic ZnO; these specific metals include Cu, Fe, and Al. The multilayer structures are assembled and fabricated under a thick film process and enabled by using a polypropylene carbonate binder system that can be removed at low temperatures under N2–H2 forming gas, permitting control of oxidation of the Cu, Fe, and Al. As a result, extremely high conductivity electrodes are fabricated and quantified through the equivalent series resistance (ESR). In addition, new electrode composite concepts, such as mixed particles of Fe–Cu cosintered in between the ZnO layers, are possible with the cold sintering process.