Inkjet-Deposited Interconnections for Electronic Packaging

Inkjet technology provides an interesting approach for electronic manufacturing. Small volumes of functional material e.g., conductive ink are dispensed on top of the substrate. Electrical circuits are formed by suitable printing sequence and sintering processes. In this paper, we present a concept of inkjet deposited System-in-Package (SiP). The package contains bare ICs and discrete passive components that are encapsulated with resin mold. Encapsulation material works as a substrate for interconnections, which are directly deposited on top of the mold. All connections between the components and connections to the I/O pins are formed by inkjetting silver nano-particle and dielectric inks. Silver nano-particles are sintered in an oven at 220°C and resistivity values lower than 5 µΩcm are reported. Precuring of a substrate in a higher temperature than the sintering temperature of silver nano-particles, decreases the resistivity of the lines. As a conclusion, the sintering profile needs to be considered carefully in order to achieve resistance requirements set by the design. This paper focuses on interconnections and system integration design aspects.