Characterisation of the fabrication process of freestanding SU-8 microstructures integrated in printing circuit board in microelectromechanical systems

Abstract

The characterization of the fabrication process to develop free-standing SU-8 structures integrated in PCBMEMS (Printing Circuit Board in Microelectromechanical Systems) technology is presented. SU-8 microcantilevers, microbridges, microchannels and micromembranes have been fabricated following the described procedure. Adherence between FR4 substrate and SU-8 has been studied using the destructive blister method, determining the surface energy. Residual thermal stress has also been analyzed for this integration and compared when using other substrates. Moreover, a study of the copper wet etching with cupric chloride has been performed in order to characterize how this isotropic etching affects the geometry of the copper structures. Finally, stiction has been observed and examined, determining the adhesion energy responsible of this effect.

Low-voltage puzzle-like fractal microelectromechanial system variable capacitor suppressing pull-in

“…Another factor to consider in this design is the upward warping that will take place due to residual stresses [11][12][13], which will affect the TR. Ideally, the top plate should be parallel to the bottom plate.…”

Fabrication process of a SU-8 monolithic pressurized microchamber for pressure driven microfluidic applications

“…2. Flame Retardant 4 (FR4) of a conventional Printed Circuit Board (PCB) is selected as a substrate due to its low cost and good adherence with SU-8 [10]. Fabrication starts by stripping the photoresist of the PCB using acetone, in order to etch the copper away by means of HCl, oxygen peroxide and DI water for 4 min (a).…”

Microsystem Technologies for Biomedical Applications

“…The low adherence of PDMS to SU8 and silicon facilitates the demolding process. We propose Flame Retadant 4 (FR4) of Printed Circuit Board (PCB) as substrate due to its low cost and good adherence with SU-8, Perdigones, Moreno, Luque & Quero (2010). However this material presents more roughness than silicon or pyrex but no problems have been observed due to this issue.…”

“…With this approach there is no need of external impulsion so the connections and the complexity of the setup of the system is reduced. As example of this kind of devices, an autonomous microdevice for the impulsion in microfluidic applications is explained in detail in Aracil, Quero, Luque, Moreno & Perdigones (2010). The one-shot pneumatic impulsion device (OPID) is composed by a chamber and a single-use microvalve that connects its output port to the external microfluidic circuit where the fluid is propelled, Fig.…”