Parylene and MEMS Technology
Posted by Sean Horn
Monday, June 18, 2012 7:52
@ 7:52 AM
In the past decade, the use of Parylene as a structural material in microelectromechanical systems (MEMS) devices has attracted significant 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 MEMS TECHNOLOGY
Parylene has an easy coating process, 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. An example of current usage would be neuron cages, which are manufactured using a multiple parylene layer etching process. Another current use is parylene enabled retinal ocular implants.
Parylene Technology for Neural Probes Applications. Changlin Pang. California Institute of Technology. Pasadena, California. 2008.
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.