Manufacture of microfluidic glass chips by deep plasma etching, femtosecond laser ablation, and anodic bonding

• Published in: Microsystem technologies 2010-08, Vol.16 (8-9), p.1485-1493
• Main Authors: Queste, S., Salut, R., Clatot, S., Rauch, J.-Y., Khan Malek, Chantal G.
• Format: Article
• Language: English
• Subjects: Applied fluid mechanics; Applied sciences; Electronics and Microelectronics; Engineering; Engineering Sciences; Exact sciences and technology; Fluid dynamics; Fluidics; Fundamental areas of phenomenology (including applications); Instrumentation; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Machine components; Mechanical Engineering; Mechanical engineering. Machine design; Mechanical instruments, equipment and techniques; Micromechanical devices and systems; Nanotechnology; Optics; Photonic; Physics; Precision engineering, watch making; Seals and gaskets; Technical Paper
• ISSN: 0946-7076; 1432-1858
• DOI: 10.1007/s00542-010-1020-1

Two dry subtractive techniques for the fabrication of microchannels in borosilicate glass were investigated, plasma etching and laser ablation. Inductively coupled plasma reactive ion etching was carried out in a fluorine plasma (C 4 F 8 /O 2 ) using an electroplated Ni mask. Depth up to 100 μm with a profile angle of 83°–88° and a smooth bottom of the etched structure (Ra below 3 nm) were achieved at an etch rate of 0.9 μm/min. An ultrashort pulse Ti:sapphire laser operating at the wavelength of 800 nm and 5 kHz repetition rate was used for micromachining. Channels of 100 μm width and 140 μm height with a profile angle of 80–85° were obtained in 3 min using an average power of 160 mW and a pulse duration of 120 fs. A novel process for glass–glass anodic bonding using a conductive interlayer of Si/Al/Si has been developed to seal microfluidic components with good optical transparency using a relatively low temperature (350°C).