Inkjet printing of SU-8 for polymer-based MEMS a case study for microlenses

Fakhfouri, V.; Cantale, N.; Mermoud, Grégory; Kim, J.Y.; Boïko, D. L.; Charbon, Edoardo; Martinoli, Alcherio; Brugger, Juergen

doi:10.1109/memsys.2008.4443679

Cited by 37 publications

(28 citation statements)

References 11 publications

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“…In this case, the diameter of the droplet was 3 mm and the surface contact angles of the SU-8 droplet was about ~10° on the plasma treated PDMS and ~58.7° on the untreated PDMS, measured by a contact angle analyzer. The simulation used 7.95 mm 2 /s for the kinematic viscosity of SU-8 3005 at an elevated temperature (between 60 °C and 95 °C) [10]. We assumed the SU-8 density of 1.075 g/cm3 and the surface tension of about 48 mN/m [10], [11].…”

Section: A Maximum Droplet Volumementioning

confidence: 99%

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Droplet backside exposure for making slanted SU-8 microneedles

Kwon

2013

2013 35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

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This paper presented a droplet backside exposure (DBE) method for making slanted microneedle structures on a flexible polymer substrate. To demonstrate the feasibility of the DBE approach, SU-8 microneedle arrays were fabricated on polydimethylsiloxane (PDMS) substrates. The length of the microneedles was controlled by tuning the volume of the SU-8 droplet, utilizing the wetting barrier phenomenon at a liquid-vapor-hydrophilic surface-hydrophobic surface interface. The experimental results showed excellent repeatability and controllability of the DBE method for microneedle fabrication. Analytical models were also studied to predict the dimensions of the microneedles, which agreed with the experimental data.

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Section: A Maximum Droplet Volumementioning

confidence: 99%

“…The simulation used 7.95 mm 2 /s for the kinematic viscosity of SU-8 3005 at an elevated temperature (between 60 °C and 95 °C) [10]. We assumed the SU-8 density of 1.075 g/cm3 and the surface tension of about 48 mN/m [10], [11]. The mass flow rate of the inlet was 2.15×10-5 kg/s.…”

Section: A Maximum Droplet Volumementioning

confidence: 99%

Droplet backside exposure for making slanted SU-8 microneedles

Kwon

2013

2013 35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC)

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“…Among the many important applications for printed electronics are photovoltaic devices 1 , sensors 2 , displays 3 and radio-frequency identification (RFID) tags 4 . Many types of functional materials can be formulated into printable inks, including electrically conducting 5 , semiconducting 6 and insulating materials 7 , as well as materials with magnetic 8 , optical 9 , chemical 10 or biological 11 functions. When comparing printing methods, inkjet allows comparably small feature size, less than 40 µm on some substrates 12 .…”

Section: Introductionmentioning

confidence: 99%

Assisted sintering of silver nanoparticle inkjet ink on paper with active coatings

et al. 2015

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Inkjet-printed metal films are important within the emerging field of printed electronics. For large-scale manufacturing, low-cost flexible substrates and low temperature sintering is desired. Tailored coated substrates are interesting for roll-to-roll fabrication of printed electronics, since a suitable tailoring of the ink-substrate system may reduce, or remove, the need for explicit sintering. Here we utilize specially designed coated papers, containing chloride as an active sintering agent. The built-in sintering agent greatly assists low-temperature sintering of inkjet-printed AgNP films. Further, we examine the effect of variations in coating pore size and precoating type. Interestingly, we find that the sintering is substantially affected by these parameters. IntroductionThe interest in printed electronics and other printed functionalities is considerable worldwide. In contrast to traditional subtractive photolithography-and etching processes, the printing process is purely additive, which means less material waste and a reduced need for processing chemicals. This results in cost savings and environmental advantages, in particular when large area coverage is desired. Additionally, printing processes have good compatibility with flexible substrates such as plastic films and paper. Applying electronic-or other functionality on flexible, low-cost substrates, across large areas in roll-to-roll processes, enables novel applications with large potential. Among the many important applications for printed electronics are photovoltaic devices . It is capable of covering large areas with simple and cost-effective setups. Furthermore, the non-contact nature of deposition allows it to be used for delicate and pressure-sensitive surfaces. The ink formulation is relatively challenging. To be reliably jetted, properties such as viscosity, surface tension, volatility and particle size need to be well controlled. To avoid aggregation, the particles are typically stabilized using polymers that adhere to the surfaces. Depending on the specific polymers and electrical charges in the system, the stabilization may be either steric, electrostatic or a combination of both (electrosteric) 13 . Some of the most common stabilizing polymers are polyvinylpyrrolidone (PVP) and polyvinyl alcohol (PVA) 14 .Electrically conducting layers are important since they are included in most applications of printed electronics. Although conductive inkjet inks may be formulated from several classes of materials, including conductive polymers 15 , carbon-based materials 16,17 , and metal nanoparticles (NPs) [18][19][20] . The metal NP inks are particularly suitable when high conductivity is required, for example when printing antennas 21 and circuit board conductors 22,23 .Paper-based substrates for printed electronics are interesting for several reasons. Environmental friendliness, flexibility and low cost are the key benefits. The physical and chemical properties may be altered by chemical additives or changes in materials and processes. Therefor...

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“…It has already been successfully used for a broad range of applications, such as among others, micro cantilevers [2], micro-optics [3], for microcapsule fabrication [4], as master for PDMS-based microfluidic setups [5], or as stamps for bio-medical purposes [6]. SU-8 and its derivatives can be prototyped by several methods, such as UV photolithography [7], two-photon polymerization [8], laser writing [9], inkjet printing (IJP) [10], or a combination of those technologies [11].…”

Section: Introductionmentioning

confidence: 99%

Inkjet Printing of High Aspect Ratio Superparamagnetic SU-8 Microstructures with Preferential Magnetic Directions

et al. 2014

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Structuring SU-8 based superparamagnetic polymer composite (SPMPC) containing Fe 3 O 4 nanoparticles by photolithography is limited in thickness due to light absorption by the nanoparticles. Hence, obtaining thicker structures requires alternative processing techniques. This paper presents a method based on inkjet printing and thermal curing for the fabrication of much thicker hemispherical microstructures of SPMPC. The OPEN ACCESSMicromachines 2014, 5 584 microstructures are fabricated by inkjet printing the nanoparticle-doped SU-8 onto flat substrates functionalized to reduce the surface energy and thus the wetting. The thickness and the aspect ratio of the printed structures are further increased by printing the composite onto substrates with confinement pedestals. Fully crosslinked microstructures with a thickness up to 88.8 μm and edge angle of 112° ± 4° are obtained. Manipulation of the microstructures by an external field is enabled by creating lines of densely aggregated nanoparticles inside the composite. To this end, the printed microstructures are placed within an external magnetic field directly before crosslinking inducing the aggregation of dense Fe 3 O 4 nanoparticle lines with in-plane and out-of-plane directions.

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Inkjet printing of SU-8 for polymer-based MEMS a case study for microlenses

Cited by 37 publications

References 11 publications

Droplet backside exposure for making slanted SU-8 microneedles

Droplet backside exposure for making slanted SU-8 microneedles

Assisted sintering of silver nanoparticle inkjet ink on paper with active coatings

Inkjet Printing of High Aspect Ratio Superparamagnetic SU-8 Microstructures with Preferential Magnetic Directions

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