Contactless In Situ Electrical Characterization Method of Printed Electronic Devices with Terahertz Spectroscopy.

Mariia Zhuldybina,François Blanchard,Xavier Ropagnol,Charles Trudeau,Martin Bolduc,Ricardo Zednik

doi:10.3390/s19030444

Abstract

Printed electronic devices are attracting significant interest due to their versatility and low cost; however, quality control during manufacturing is a significant challenge, preventing the widespread adoption of this promising technology. We show that terahertz (THz) radiation can be used for the in situ inspection of printed electronic devices, as confirmed through a comparison with conventional electrical conductivity methods. Our in situ method consists of printing a simple test pattern exhibiting a distinct signature in the THz range that enables the precise characterization of the static electrical conductivities of the printed ink. We demonstrate that contactless dual-wavelength THz spectroscopy analysis, which requires only a single THz measurement, is more precise and repeatable than the conventional four-point probe conductivity measurement method. Our results open the door to a simple strategy for performing contactless quality control in real time of printed electronic devices at any stage of its production line.

Highlights

Printable electronics (PE) is an advanced manufacturing technology that is of significant interest to a large range of industries, from consumer goods, electronics, aerospace, automotive, pharmaceutical, biomedical, to textiles and fashion [1,2,3,4,5]
Five vortex phase plate (VPP) samples with different conductivities were characterized by the THz-Time-domain spectroscopy (TDS) described above
We developed a quality control bar for industrial production of PE devices based on a VPP working in the THz range

Summary

Introduction

Printable electronics (PE) is an advanced manufacturing technology that is of significant interest to a large range of industries, from consumer goods, electronics, aerospace, automotive, pharmaceutical, biomedical, to textiles and fashion [1,2,3,4,5]. It offers an attractive alternative to conventional circuit manufacturing by enabling lower-cost, maskless, and rapid production of customized electronic devices [6]. PE is compatible with a wide range of substrates, as long as they are not porous and can resist all fabrication steps, including pre- and post-printing processes [7]. Post-printing processes play a key role in the manufacturing of PE devices. The most commonly used sintering approaches are conventional thermal annealing, electrical sintering, microwave, and photonic sintering by either continuous-wave laser irradiation or Sensors 2019, 19, 444; doi:10.3390/s19030444 www.mdpi.com/journal/sensors

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