Ensemble Modeling of In Situ Features for Printed Electronics Manufacturing With In Situ Process Control Potential

Aerosol jet printing (AJP) is a direct-write-based printed electronics process that is capable to print various materials with fine features [C. Goth et al., “Aerosol jet printing on rapid prototyping materials for fine pitch electronic applications,” in Proc. IEEE 61st Electron. Compon. Technol. Conf., Lake Buena Vista, FL, USA, 2011, pp. 1211-1216.]. It eliminates the complex masking process in traditional semiconductor manufacturing, thus enables flexible electronics designs and reduces manufacturing cost. However, the quality control of AJP processes is still a challenging problem, primarily due to the lack of understanding of the potential root causes of the quality issues. There is a complex interaction among the process setting variables, in situ features, and product quality in AJP processes. In this letter, an ensemble modeling strategy is proposed to quantify the effect of the process setting variables on the in situ features, and the effect of the in situ features on the product quality in a two-level hierarchical way. By identifying significant in situ features as responses for the process setting variables, as well as significant predictors for the product quality in a joint model estimation problem, the proposed model has a hierarchical variable relationship to enable the in situ process control for variation reduction and defect mitigation. A real case study is investigated to demonstrate the advantages of the proposed method.