Aachen, Germany – Technologist René Sanders gave a presentation about the manufacturing of shims for microfluidics (µF) on May 8–9, 2017, during the 4th International Conference on Polymer Replication on Nanoscale (PRN 2017).
Microfluidic devices manufacturing
Microfluidic devices like barriers, channels, jets, meshes, nozzles, and complete functional chips, can be manufactured in silicon, glass, polymers or metal. At the Philips Innovation Services MEMS foundry, microfluidic devices are manufactured with MEMS & thin film process steps: lithography, nano-imprint, dry and wet etching and deposition, and using a variety of laser systems. The flexibility of a laser allows for fast prototyping of precise structures, enabling short iteration loops to speed up microfluidic device development.
Microfluidic device standardization project
The presentation from René Sanders dives into the ENIAC MFManufacturing project, a European initiative for the standardization and manufacturability of complex microfluidic devices. The goal of this project is to bring microfluidic devices manufacturing to the same maturity and industrialization level as electronic devices, a requirement for successful integration into the MEMS production process.
The laser part of this project focusses on standardization to 15 x 15 x 1 mm³ units with fixed in- and outlet dimensions and positions. The European project ENIAC made it possible to demonstrate the feasibility of microfluidic device manufacturing, using laser in combination with injection molding.
As demonstrators, two basic µF building blocks were made: a µF mixing channel and µF capillary pumps. Partners within the ENIAC project have conducted functional tests of the µF mixing channel and µF capillary pumps. Conclusions from the functional tests of the µF mixing channel and µF capillary pumps:
- Mixer: channel filled with small ribs enhances mixing
- Capillary pump: array of pillars increases capillary force
Using the laser method in the microfluidic device manufacturing process
The basic process flow for microfluidic device manufacturing using the laser-polymer-molding-method was tested:
- Laser ablation of µF structures
- Polycarbonate master
- Nickel shim
- Injection molded COP (cyclo olefin polymer) part
- Dicing into individual parts
Working with laser allows for precise structures while simultaneously allowing flexibility in the development process with rapid iterations and variations. Once a good design is established experimentally, the polymer structures are electroplated and serve as a shim for injection molding, transitioning from single piece prototyping to mid and high volume production.
Advantages of the laser method
Laser has the limitation that only polycarbonate can be used. However, through the injection molding route, a large number of polymers can be formed, such as COP, COC, PMMA, and of course PC. The laser method is capable of making structures that are impossible or difficult to create using conventional methods (e.g. milling). See as an example the pile structures in the presentation.
More information on microfluidic devices & prototyping:
Technologist, device assembly prototyping