Optimized SU-8 Processing for Low-Cost Microstructures Fabrication without Cleanroom Facilities

The study and optimization of epoxy-based negative photoresist (SU-8) microstructures through a low-cost process and without the need for cleanroom facility is presented in this paper. It is demonstrated that the Ultraviolet Rays (UV) exposure equipment, commonly used in the Printed Circuit Board (PCB) industry, can replace the more expensive and less available equipment, as the Mask Aligner that has been used in the last 15 years for SU-8 patterning. Moreover, high transparency masks, printed in a photomask, are used, instead of expensive chromium masks. The fabrication of well-defined SU-8 microstructures with aspect ratios more than 20 is successfully demonstrated with those facilities. The viability of using the gray-scale technology in the photomasks for the fabrication of 3D microstructures is also reported. Moreover, SU-8 microstructures for different applications are shown throughout the paper.

[1]  Sung-Keun Lee,et al.  3D microfabrication with inclined/rotated UV lithography , 2004 .

[2]  Bozena Kaminska,et al.  PDMS as a sacrificial substrate for SU-8-based biomedical and microfluidic applications , 2008 .

[3]  George M. Whitesides,et al.  Generation of chrome masks with micrometer-scale features using microlens lithography , 2002 .

[4]  Jian Zhang,et al.  Characterization of the polymerization of SU-8 photoresist and its applications in micro-electro-mechanical systems (MEMS) , 2001 .

[5]  A. Neyer,et al.  Novel exposure methods based on reflection and refraction effects in the field of SU-8 lithography , 2006 .

[6]  Graça Maria Henriques Minas,et al.  Pressure Sensor for Gastrointestinal Intraluminal Measuring , 2014, BIODEVICES.

[7]  David F. Moore,et al.  Micromechanical testing of SU-8 cantilevers , 2005 .

[8]  Ivo Rendina,et al.  Photomasks Fabrication Based on Optical Reduction for Microfluidic Applications , 2013, Micromachines.

[9]  S. Büttgenbach,et al.  SU8-micromechanical structures with in situ fabricated movable parts , 2002 .

[10]  José Higino Correia,et al.  A SU-8 fluidic microsystem for biological fluids analysis , 2005 .

[11]  Sujeet K. Sinha,et al.  Releasing high aspect ratio SU-8 microstructures using AZ photoresist as a sacrificial layer on metallized Si substrates , 2013 .

[12]  Kwang-Cheol Lee,et al.  Fabrication and characterization of freestanding 3D carbon microstructures using multi-exposures and resist pyrolysis , 2008 .

[13]  M. Madou,et al.  One-step maskless grayscale lithography for the fabrication of 3-dimensional structures in SU-8 , 2011 .

[14]  C. Greiner,et al.  SU-8: a photoresist for high-aspect-ratio and 3D submicron lithography , 2007 .

[15]  Mathieu Hautefeuille,et al.  Rapid fabrication of on-demand high-resolution optical masks with a CD-DVD pickup unit. , 2014, Applied optics.

[16]  Wei Duan,et al.  A protocol for improving fabrication yield of thin SU-8 microcantilevers for use in an aptasensor , 2015 .

[17]  A. Mason,et al.  Lab-on-CMOS integration of microfluidics and electrochemical sensors. , 2013, Lab on a chip.

[18]  N. Bhat,et al.  CHARACTERIZATION OF OPTICAL PROPERTIES OF SU-8 AND FABRICATION OF OPTICAL COMPONENETS , 2009 .

[19]  G. Minas,et al.  SU-8 microfluidic mixer for use in lab-on-a-chip devices for biological fluids analyses , 2006, 2006 IEEE International Conference on Industrial Technology.

[20]  Marc Madou,et al.  SU-8 Photolithography and Its Impact on Microfluidics , 2011 .

[21]  Xin Zhang,et al.  Fabrication of three-dimensional microstructures based on singled-layered SU-8 for lab-on-chip applications , 2006 .

[22]  Pranabendu Ganguly,et al.  Microstructuring of SU-8 Resist for MEMS and Bio-Applications , 2010 .