Additive Fabrication of Conductive Patterns by a Template Transfer Process Based on Benzotriazole Adsorption As a Separation Layer

Abstract

The traditional subtractive process to fabricate conductive patterns is environmentally harmful, wasteful, and limited in line width. The additive process, including direct printing of conductive paste or ink, direct printing of catalytic ink, laser-induced forward transfer, etc., can solve these problems. However, the current additive process also faces many difficulties such as low electrical and adhesion properties, low pattern thickness, high cost, etc. Benzotriazole (BTA), as widely used corrosion inhibitor, can be adsorbed onto a copper surface. The electroplated copper film on BTA-adsorbed copper foil shows poor adhesion. On the basis of this phenomenon, a novel template transfer process to additively fabricate conductive patterns has been developed. A permeant antiadhesive mask is printed on carrier copper foil, and then, BTA is adsorbed onto the exposed area of the carrier foil, thus forming the template. The template is electroplated to grow conductive patterns in the exposed parts, and then can be adhered to the flexible substrate. The substrate is peeled off, with the transfer of the conductive patterns to the substrate, to form the designed conductive patterns on PET. By reimmersing the template into BTA solution, the template can be used again. The mechanism of BTA adsorption and the reason for the low peeling strength are researched using Raman spectra, XPS and electrochemical impedance spectroscopy. Copper patterns more than 20 μm in thickness can be prepared on PET, the resistivity of the prepared copper patterns is 2.01 μΩ cm, which is about the same as bulk copper, and the peeling strength of the pattern on PET is measured to be 6.97 N/cm. This template transfer process, with no waste, low pollution, high electrical and adhesion properties, and low cost, shows high potential in the large scale manufacturing of electronic devices, such as RFID circuitry, FPCs, etc.

Additive Preparation of Conductive Circuit Based on Template Transfer Process Using a Reusable Photoresist

“…R e represents the impendence of the electrolyte. Q 1 represents the capacitive behavior of the epitaxial layer on the carrier copper (mainly affected by the interfacial capacitance of the copper/oxide layer), and R 1 represents the resistive behavior of the oxide layer …”

“…Q 1 represents the capacitive behavior of the epitaxial layer on the carrier copper (mainly affected by the interfacial capacitance of the copper/ oxide layer), and R 1 represents the resistive behavior of the oxide layer. 42 Q 2 represents the capacitive behavior of the electrical double layer at the oxide/electrolyte interface with the PDMS nanolayer as the dielectric, and R 2 represents its resistive behavior. Since the anti-adhesion film mainly affects the electrical behavior of the oxide/electrolyte interface, its capacitance (C) can be calculated from Q 2 and R 2 by 57 As a result, the thickness (d) of the antiadhesion film can be obtained from the parallel capacitor equation d = ε 0 εS/C, in which ε 0 represents a vacuum dielectric constant of 8.85 × 10 −14 F/cm, S represents the surface area of anti-adhesion film, and ε represents the relative permittivity of the anti-adhesion film, which was also measured via the EIS test and calculated to be 53.75, as shown in Figure S4.…”

“…41 However, the conductive circuits cannot be directly fabricated on any substrate by electroplating as the electrodeposition of the metal is only available when a conductive layer is coated on the substrate for current conduction. In a previous research, 42 we have developed a template transfer process based on electroplating of thick pure metal as well as interfacial selfassembly and screen printing for the additive fabrication of conductive circuits on a nonconductive polymer substrate. The fabrication steps include the preparation of the template and the circuits: an anti-adhesion mask is first prepared on the carrier copper foil by screen printing followed by benzotriazole (BTA) adsorption on the exposed copper surface to prepare the template.…”

Highly Conductive and Fatigue‐Free Flexible Copper Film Electrode Fabricated by a Facile Dry Transfer Technique

“…Functionalizing the donor surfaces with adhesion reduction layers cannot resist to high temperature process, for the coating material is organic. [32] As there is no heterogeneous material access in the transfer process, the method of stress inducing delamination is simple, nondestructive, and compatible with high temperature techniques, which is rather suitable for the transfer of The flexible electrodes with excellent electrical and mechanical performance play critical and fundamental roles in the wearable electronics. In this work, highly conductive and fatigue-free flexible copper thin-film electrodes on polyethylene terephthalate substrate are successfully fabricated by a facile, nondestructive, and heat-resistant dry transfer technique.…”

Microscale Metallization on Conducting Polyaniline Patterns

“…Fabrication of metallic nanomaterial patterns is very important in the electronic industry . A variety of techniques for producing these metallic nanoparticle patterns have been developed, such as ink‐jet printing, direct writing, electroplating, screen printing, and soft lithography including micro‐contact printing (μCP) and nanoimprint lithography (NIL) . Nevertheless, adapting a fair number of techniques to industrial uses is difficult due to the relatively complicated processes and/or the expensive installations.…”