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Micromachines 2018, 9(12), 639;

Bonding Strength of a Glass Microfluidic Device Fabricated by Femtosecond Laser Micromachining and Direct Welding

Department of Electronics and Control Engineering, Hanbat National University, Daejeon 34158, Korea
Department of Laser and Electron Beam Application, Korea Institute of Machinery and Materials, Daejeon 34103, Korea
Authors to whom correspondence should be addressed.
Received: 31 October 2018 / Revised: 24 November 2018 / Accepted: 30 November 2018 / Published: 3 December 2018
(This article belongs to the Special Issue MEMS/NEMS Sensors: Fabrication and Application)
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We present a rapid and highly reliable glass (fused silica) microfluidic device fabrication process using various laser processes, including maskless microchannel formation and packaging. Femtosecond laser assisted selective etching was adopted to pattern microfluidic channels on a glass substrate and direct welding was applied for local melting of the glass interface in the vicinity of the microchannels. To pattern channels, a pulse energy of 10 μJ was used with a scanning speed of 100 mm/s at a pulse repetition rate of 500 kHz. After 20–30 min of etching in hydrofluoric acid (HF), the glass was welded with a pulse energy of 2.7 μJ and a speed of 20 mm/s. The developed process was as simple as drawing, but powerful enough to reduce the entire production time to an hour. To investigate the welding strength of the fabricated glass device, we increased the hydraulic pressure inside the microchannel of the glass device integrated into a custom-built pressure measurement system and monitored the internal pressure. The glass device showed extremely reliable bonding by enduring internal pressure up to at least 1.4 MPa without any leakage or breakage. The measured pressure is 3.5-fold higher than the maximum internal pressure of the conventional polydimethylsiloxane (PDMS)–glass or PDMS–PDMS bonding. The demonstrated laser process can be applied to produce a new class of glass devices with reliability in a high pressure environment, which cannot be achieved by PDMS devices or ultraviolet (UV) glued glass devices. View Full-Text
Keywords: microfluidic; femtosecond laser; rapid fabrication; glass welding; bonding strength microfluidic; femtosecond laser; rapid fabrication; glass welding; bonding strength

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Kim, S.; Kim, J.; Joung, Y.-H.; Choi, J.; Koo, C. Bonding Strength of a Glass Microfluidic Device Fabricated by Femtosecond Laser Micromachining and Direct Welding. Micromachines 2018, 9, 639.

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