3D Microfluidics from Hard Materials

• Anisotropic wet-chemical etching of Si with KOH: inexpensive batch process, smooth surface, side wall angle depends on crystal orientation
• Anisotropic plasma-enhanced dry Si etching (ASE/Bosch process): single wafers, dense structures, vertical side walls
• Super-rough surfaces by etching in SF₆/C₄F₈ plasma
• Isotropic wet etching of glass with HF: round channels, 3 – 700 µm deep
• Ultrasonic drilling and micro-blasting for 150 – 1000 µm thick glass, Si, quartz

a) Etched channel structure of a micromachined device, b) Micro pores, realized by ASE at presence of insulated platinum electrodes, c) Etched sieve structure, d) GeSiM dispenser structure: View from the pump chamber of the fluid inlet (From left to right)