Pad-Printing as a Fabrication Process for Flexible and Compact Multilayer Circuits

Abstract

The purpose of this paper is to present a newly developed process for the fabrication of multilayer circuits based on the pad-printing technique. Even though the maturity level, in terms of accuracy, substrate type and print size of several printing industrial processes is relatively high, the fabrication complexity of multilayer printed electronics remains relatively high. Due to its versatility, the pad-printing technique allows the superposition of printed conductive and insulating layers. Compared to other printing processes, its main advantage is the ability to print on various substrates even on flexible, curved or irregular surfaces. Silver-based inks were used for the formulation of conductive layers while UV inks were employed to fulfil the functionality of the insulating layers. To demonstrate the functionality of the pad-printing results, a multilayer test pattern has been designed and printed on Kapton®. Furthermore, to demonstrate the efficacy of this approach, a multilayer circuit composed of three stacked layers has been designed and printed on various substrates including Kapton®, paper and wood. This electronic circuit controls an array of LEDs through the manipulation of a two-key capacitive touch sensor. This study, allowed us to define recommendations for the different parameters leading to high printing quality. We expect a long-term beneficial impact of this study towards a low-cost, fast, and environmental-friendly production of printed electronics.

Recent Progress in Printed Photonic Devices: A Brief Review of Materials, Devices, and Applications

“…Pad-printing technology can print on diverse materials such as ceramics, glass, plastics, coated substrates, metals, wood, automotive components, pharmaceuticals, cosmetics, food, and other similar substances. The pad-printing process comprises multiple stages or phases as shown in Figure 9 [ 83 ]. In step A, the components comprising a resting place are the pad (1), substrate (2), engraved pattern in the ink (3), cliché (4), and ink cup (5).…”

“… Schematic diagram of pad-printing process ( A ) Rest position with (1) Pad, (2) Substrate, (3) Inked engraved pattern, (4) Cliché and (5) Ink cup. ( B ) Shows the movement of the pad and ink cup at the same time ( C ) patterned ink film is transferred to the pad ( D ) the pad is moved towards the substrate ( E ) the patterned ink film is deposited on the substrate ( F ) the pad moves to its initial position [ 83 ]. …”

A Review of Manufacturing Methods for Flexible Devices and Energy Storage Devices

“…This limitation prevents the integration of multiple functionalities on the device, greatly restricting its practicality. Therefore, it is essential to prioritize the research and design of multilayer flexible electronic devices [ 126 , 127 , 128 , 129 , 130 ] to overcome these limitations and enhance their functionality.…”

Wearable UHF-RFID Sensor for Wetness Detection

“…Pad printing, which is a versatile offset printing technique, is one of the oldest printing techniques. Thanks to the developments in pad printing, the application areas of pad printing have expanded from conventional textiles to sensors, biosensors, RFID tags, and photovoltaic cells [33], [34]. The first step in the pad printing method is to create the desired pattern on the printing plate called cliché.…”

“…Finally, the silicone pad first takes the pattern onto itself and then transfers it to the substrate [22], [34], [35]. Pad printing becomes advantageous when compared to other printing methods due to its low cost, simplicity, fastness, ability to work even with high viscosity inks, printing on a wide variety of substrates like flexible, curved, and rough surfaces, and printing layer by layer [33]. Literature reveals that many textile-based sensors and antennas have been introduced.…”