Rapid hot embossing of polymer microstructures using carbide-bonded graphene coating on silicon stampers

• Published in: Surface & coatings technology Vol. 258; pp. 174 - 180
• Main Authors: Xie, Pengcheng, He, Peng, Yen, Ying-Chieh, Kwak, Kwang Joo, Gallego-Perez, Daniel, Chang, Lingqian, Liao, Wei-ching, Yi, Allen, Lee, L. James
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.11.2014; Elsevier
• Subjects: Applied sciences; Arrays; Carbide-bonded graphene coating; Coating; Cross-disciplinary physics: materials science; rheology; Cycle time; Electrically conductive; Embossing; Exact sciences and technology; Graphene; Heating; Hot embossing; Materials science; Metals. Metallurgy; Microstructures; Physics; Production techniques; Rapid mold heating and cooling; Silicon; Surface treatment; Surface treatments; Rapid mold heating and cooling; Microstructures; Hot embossing; Carbide-bonded graphene coating; Surface treatments; Microstructure; Polymers; Coatings; Heat rate; Rapid cooling; Carbides
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2014.09.034

In this study, we present a novel rapid hot micro-embossing technique utilizing micro-patterned silicon stampers coated with a newly developed carbide-bonded graphene network to implement rapid heating and cooling. The graphene coating layer is highly thermally conductive and a ~45nm thick coating layer on silicon wafer could serve as a highly efficient heating film because of its high electrical conductivity of 1.98×104S/m and low surface resistivity of 20.4Ω. Heating rates of 5–10°C/s could be achieved by employing a DC operating voltage under 50V to allow the contact surface temperature of the stamper and the polymer substrate reaching glass transition temperature within 10s for rapid embossing of microscale features. Since the graphene coating is very thin, the stamper surface could be cooled rapidly after embossing to keep the cycle time shorter than 25s. This novel hot embossing technique was successfully implemented to imprint microchannel and microlens arrays on thermoplastic polymer substrates with high precision. Compared with conventional hot embossing, our facile method could achieve better replication fidelity with much less cycle time. •Rapid hot embossing using carbide-bonded graphene coated Si stampers•The graphene coating serves as a heating film with a surface resistivity of 20.4Ω.•A heating rate of 5.5°C/s could be achieved by employing a DC voltage under 50V.•Stamper surface could be cooled rapidly keeping the cycle time shorter than 25s.•It was successfully implemented to imprint microchannel and microlens arrays.