Mechanical and Microfluidic Interconnects Fabricated in SU-8 Photopolymer

SU-8 photopolymer is employed to fabricate interlocking structures through which high-density fluidic connections are provided between microchannel containing substrates. Each interconnect is composed of a compliant SU-8 cylinder that deforms to fit when inserted into a silicon or SU-8 hole that is 1–2 μm smaller in initial diameter. Interconnects up to 200 μm in outer radii in SU-8 films 200 μm thick were analyzed and simulated using ANSYS to determine relative strengths and weaknesses of different interconnect designs, as well as determine forces required for assembly and disassembly. Fabricated 200 μm radius interconnects were tested both mechanically and for fluid pressurization. First-order pull-out forces using weights were measured to be 35 mN for fully assembled 100 μm deep interconnects. Pressure testing on a microfluidic board resulted in a maximum pressure of 30 psi (200 kPa) with no leakage using a computer controlled pressure source and water.Copyright © 2005 by ASME