Fabrication of Flexible Hybrid Circuits in Parylene

• Autor(a) principal: Rodrigues, Pedro Carvalho
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/152017
• topic: Flexible Hybrid Electronics; Double Layer; Parylene C; Silicon Integrated Circuit; Temperature Sensing; Domínio/Área Científica::Engenharia e Tecnologia::Outras Engenharias e Tecnologias

In recent years, with the increasing research interest in personalized medicine, new and disruptive technologies such as the Internet of Things (IoT) and flexible wearable electronics have emerged and have become trending topics in the scientific community. Despite consistent progress in the area of fully flexible electronics, these continue to reveal some restrictions, which can be overcome by traditional silicon integrated circuits (ICs). The combination between these technologies generated the new concept of flexible hybrid electronics (FHE) igniting a new generation of wearable health monitoring systems. This thesis reports a new way to the use parylene C as substrate, dielectric and encap- sulation layers to accommodate silicon ICs, surface mounted devices (SMDs) and thin metal layers, in order to create flexible and conformable double layered hybrid sensing membranes for body temperature monitoring, one of the most relevant physiological pa- rameters upon a medical diagnosis, since it’s among the main indicators for inflammation and infection. To achieve the thin metal and parylene C layers, thin-film microfabrica- tion techniques were employed and corroborated by superficial, electrical and structural characterization techniques. In addition the establishment of an electrical connection by the integration of silicon ICs and SMDs onto the thin metal layer was successfully tested using a low-temperature solder paste and a reflow oven, which reproduced a previously inputted time-temperature profile. Furthermore, this thesis analyses the repercussions of this integration procedure on the peel off process. Throughout this work, commercial body temperature measuring circuits were used as inspiration for the temperature sensing circuits developed. The interface between the produced membranes and their respective microcontrollers was also tested, although no temperature measurements were obtained due to parylene’s performance as a dielectric. The successful production of a fully functional flexible and conformable double layered hybrid sensing membrane could propel the adaptation of other rigid health monitoring electronics to FHE membranes, further engraving this technology into people’s daily lives.