Inkjet Printing Design Rules Formalization and Improvement

A process design kit (PDK) or Technology Design kit (TDK) is a set of files which describes manufacturing parameters that are relevant for the designers (fabrication layers, electrical parameters and design rules) for a certain technology of a given foundry. PDKs customize CAD/EDA tools used by designers, providing enough abstraction of technological details to facilitate the design of (organic electronics) circuits. Design rules are a set of geometric restrictions imposed to the different layers fabricated by the foundry that designers have to respect. By taking the geometric design rules into account, the design engineers address physical layout to develop devices and circuits without the need of a deep knowledge of process and materials. These rules guarantee their manufacturability and enable working circuits with an optimal balance of yield versus integration density. Design rules for inkjet printing are similar to general design rules for photolithographic processes but also need to cope with the failures related to additive printing of inks and related curing. In this paper, parameterizable cells (PCells) have been used to automate the generation of a complete set of structures to formalize and arrive at technology-independent design rules. A set of test vehicles has been designed, printed and characterized demonstrating the methodology to comprehensively capture the design criteria for inkjet printing technology. For improving design rules and scaling down device dimensions, we present a design approach that combines pre-patterned, high-resolution substrates with digital inkjet fabrication as a demonstration of the capabilities of combining inkjet with other fabrication technologies.