Inkjet-printed interconnects for unpackaged dies in printed electronics

• Published in: Electronics letters Vol. 55; no. 5; pp. 252 - 254
• Main Authors: Bezuidenhout, P, Smith, S, Land, K, Joubert, T-H
• Format: Journal Article
• Language: English
• Published: The Institution of Engineering and Technology 07.03.2019
• Subjects: Circuits and systems; flexible electronics; flexible substrates; hybrid inkjet‐printed paper‐based circuit; ink jet printing; inkjet‐printed interconnection; integrated circuit technology; paper‐based electronics platforms; printing protocols; radiofrequency identification; silicon; silver; silver interconnects; unpackaged RFID tag die; unpackaged silicon; radiofrequency identification; flexible electronics; printing protocols; paper-based electronics platforms; flexible substrates; silicon; unpackaged RFID tag die; inkjet-printed interconnection; hybrid inkjet-printed paper-based circuit; unpackaged silicon; silver; silver interconnects; integrated circuit technology; ink jet printing
• ISSN: 0013-5194; 1350-911X; 1350-911X
• DOI: 10.1049/el.2018.6839

This work details manufacturing processes developed to integrate an unpackaged silicon die onto a paper substrate, as part of constructing a hybrid inkjet-printed paper-based circuit. This integration between rigid components and flexible substrates is beneficial in low-cost applications and capitalises on the advantages of both the well-established integrated circuit technology and the emerging paper-based electronics platforms. A superglue incline at the chip edge formed a ramp for printing the silver interconnects between the paper-based circuit and the chip pads. Two printing protocols are compared, the first a single layer using 5 μm drop spacing, and the second using a 35 μm drop spacing for three layers. An unpackaged RFID tag die is successfully integrated and is presented as proof of concept.