3D microfluidic cartridges by gas pressure assisted thermal bonding of microthermoformed films

Microthermoforming of film substrates is an emerging technology to form thin-walled microfluidic Lab-on-a-Chip cartridges. We present a process chain to fabricate thin-walled 3D microfluidic cartridges by thermally bonding a stack of microthermoformed polymer layers. The three layer bond stack comprises an upper and a lower microthermoformed film substrate separated by a flat intermediate film layer. For thermal bonding the films are pressed together by gas pressure, eliminating the need for any structure dependent tools. The capabilities of the process chain are demonstrated by bonding a complex microfluidic LabDisk demanding two stacked fluidic layers on top of each other.