Parylene and MEMS Technology

Parylene’s application as a structural material in microelectromechanical systems (MEMS) devices has garnered notable attention. Parylene C, known for its biocompatibility, is widely used in implantable medical devices. Parylene C is also compatible with MEMS microfabrication processes.

What are MEMS?

Microelectromechanical systems (MEMS) is the technology of very small devices; it merges at the nano-scale into nanoelectromechanical systems (NEMS) and nanotechnology. MEMS are made up of components between 1 to 100 micrometres in size (i.e. 0.001 to 0.1 mm), and MEMS devices generally range in size from 20 micrometres (20 millionths of a metre) to a millimetre (i.e. 0.02 to 1.0 mm). They usually consist of a central unit that processes data (the microprocessor) and several components that interact with the outside such as microsensors.

What is Parylene?

Parylene is a polymer applied through a deposition process. Parylene coatings are completely conformal, have a uniform thickness and are pinhole free. Parylene is chemically and biologically inert and stable and make excellent barrier material. Parylene has excellent electrical properties: low dielectric constant and loss with good high-frequency properties; good dielectric strength; and high bulk and surface resistance.

Parylene and and MEMS Technology

Parylene provides controllable conformal coating thickness and is highly compatible with the plasma etching process. As a result of this, Parylene has been easily integrated with the fast growing MEMs technology. Neuron cages are an example of an application, crafted through a refined multiple Parylene layer etching technique. Another common application includes using Parylene for retinal ocular implants.

References:
1.] Parylene Technology for Neural Probes Applications. Changlin Pang. California Institute of Technology. Pasadena, California. 2008.
2.] A Parylene MEMS Electrothermal Valve. Po-Ying Li et al. J Microelectromech Syst. 2009 December; 18(6): 1184–1197. doi: 10.1109/JMEMS.2009.2031689.