Hydrogen evolution assisted cyclic electroplating for lateral copper growth in wearable electronics

• Published in: Journal of electroanalytical chemistry (Lausanne, Switzerland) Switzerland), 2021-12, Vol.902, p.115796, Article 115796
• Main Authors: Rosa-Ortiz, Sabrina M., Phan, Kat-Kim, Khattak, Nida, Thomas, Sylvia W., Takshi, Arash
• Format: Article
• Language: English
• Subjects: Bubbles; Circuit boards; Copper; Copper nanostructure; Electric potential; Electrodeposition; Electronics; Electroplating; Hydrogen; Hydrogen evolution; Hydrogen evolution assisted (HEA) electroplating; Lateral growth; Light emitting diodes; Nanostructure; Plating; Printed circuits; Substrates; Voltage; Wearable technology
• ISSN: 1572-6657; 1873-2569
• DOI: 10.1016/j.jelechem.2021.115796

[Display omitted] •Hydrogen evolution assisted (HEA) electroplating was applied for copper growth.•Cyclic electroplating method was used to control the copper nanostructure.•Scan rate of 100 mV/s has been identified for fast growth of copper. Recent progress in hydrogen evolution assisted (HEA) electroplating has shown promises for fast lateral growth of copper on various rigid and flexible substrates. In this method, concurrent to the copper reduction, hydrogen bubbles are generated at the cathode resulting in a porous copper layer with a growth rate a few orders of magnitude faster than the standard electroplating method. However, the application of constant voltage does not allow bubbles to leave the surface resulting in non-uniform copper growth and unpredictable nanostructures. To allow the hydrogen bubbles to leave the surface, we have applied a cyclic electroplating method in a voltage range that the electroplating alternates between the HEA and non-HEA modes. The effect of the voltage range and the voltage scan rate on the lateral growth of copper and the quality of the copper layer were investigated on a patterned copper track on a standard printed circuit board (PCB). The fastest growth rate of 55 µm/s was obtained for a voltage range between −1.5 V and −0.8 V with a scan rate of 100 mV/s. The scanning electron microscopy (SEM) images of different samples revealed that the scan rate affects the nanostructure of the grown copper layer. The feasibility of applying the HEA cyclic electroplating method for developing wearable electronics was demonstrated by growing copper on a piece of fabric to make contact with the pins of a light emitting diode.