LF55GN Photosensitive Flexopolymer: A New Material for Ultrathick and High-Aspect-Ratio MEMS Fabrication

Sayah, A.; Parashar, V.K.; Gijs, Martin A. M.

doi:10.1109/jmems.2007.896705

Cited by 6 publications

(8 citation statements)

References 35 publications

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“…The advantages of micromolding include the reusable mold and bench-top fabrication. The use of spin-cast micromolding (SCμM) is simpler and easier to implement than RIE etching or laser (Garra et al 2002;Graubner et al 2002;Sayah et al 2007;Sia and Whitesides 2003). Spincasting techniques are also gentle in the sense that no high-energy ablation mechanism or harsh chemicals are required, which can be a concern when dealing with polymers and very thin-film metals.…”

Section: Electrode Designmentioning

confidence: 99%

“…Additionally, gold does not form a surface oxide, making it suitable for electrode recording sites (Cogan 2008). PDMS shape and topography can be controlled by several methods, including photosensitive polymerization, laser ablation, reactive ion etching (RIE), and micromolding (Garra et al 2002;Graubner et al 2002;Sayah et al 2007;Sia and Whitesides 2003).…”

Section: Introductionmentioning

confidence: 99%

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Highly-compliant, microcable neuroelectrodes fabricated from thin-film gold and PDMS

McClain

Clements

Shafer

et al. 2011

Biomed Microdevices

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Bio-electrodes have traditionally been made of materials such as metal and silicon that are much stiffer than the tissue from which they record or stimulate. This difference in mechanical compliance can cause incomplete or ineffective contact with the tissue. The electrode stiffness has also been hypothesized to cause chronic low-grade injury and scar-tissue encapsulation, reducing stimulation and recording efficiency. As an initial step to resolve these issues with electrode performance, we have developed and characterized electrically-functional, low-Young's modulus, microcable-shaped neuroelectrodes and demonstrated electrophysiological recording functionality. The microcable geometry gives the electrodes a similar footprint to traditional wire and microwire neuroelectrodes, while reducing the difference in Young's modulus from nervous tissue by orders of magnitude. The electrodes are composed of PDMS and thin-film gold, affording them a high-level of compliance that is well suited for in vivo applications. The composite Young's modulus of the electrode was experimentally determined to be 1.81 ± 0.01 MPa. By incorporating a high-tear-strength silicone, Sylgard 186, the load at failure was increased by 92%, relative to that of the commonly used Sylgard 184. The microcable electrodes were also electromechanically tested, with measurable conductivity (220 kΩ) at an average 8% strain (n = 2) after the application of 200% strain. Electrophysiological recording is demonstrated by wrapping the electrode around a peripheral nerve, utilizing the compliance and string-like profile of the electrode for effective recording in nerve tissue.

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Section: Electrode Designmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Highly-compliant, microcable neuroelectrodes fabricated from thin-film gold and PDMS

McClain

Clements

Shafer

et al. 2011

Biomed Microdevices

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“…The incident angle of the collimated UV light in air is determined from the tilting angle of the photoresist container with LF55GN, which is controlled by the stepper motor and the computer controller. 11 It is very low compared to the absorption coefficient of SU8, which is 31 cm −1 at the same wavelength. 3.…”

Section: Photolithography Characterization Formentioning

confidence: 91%

“…11,12 Especially, the fabrication process for the polyurethane photoresist does not require softbake and postexposure bake steps. 11,12 Especially, the fabrication process for the polyurethane photoresist does not require softbake and postexposure bake steps.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of three-dimensional millimeter-height structures using direct ultraviolet lithography on liquid-state photoresist for simple and fast manufacturing

Kim

Yoon

2015

J. Micro/Nanolith. MEMS MOEMS

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A rapid three-dimensional (3-D) ultraviolet (UV) lithography process for the fabrication of millimeter-tall high aspect ratio complex structures is presented. The liquid-state negative-tone photosensitive polyurethane, LF55GN, has been directly photopatterned using multidirectionally projected UV light for 3-D micropattern formation. The proposed lithographic scheme enabled us to overcome the maximum height obtained with a photopatternable epoxy, SU8, which has been conventionally most commonly used for the fabrication of tall and high aspect ratio microstructures. Also, the fabrication process time has been significantly reduced by eliminating photoresist-baking steps. Computer-controlled multidirectional UV lithography has been employed to fabricate 3-D structures, where the UV-exposure substrate is dynamically tilt-rotating during UV exposure to create various 3-D ray traces in the polyurethane layer. LF55GN has been characterized to provide feasible fabrication conditions for the multidirectional UV lithography. Very tall structures including a 6-mm tall triangular slab and a 5-mm tall hexablaze have been successfully fabricated. A 4.5-mm tall air-lifted polymer-core bowtie monopole antenna, which is the tallest monopole structure fabricated by photolithography and subsequent metallization, has been successfully demonstrated. The antenna shows a resonant radiation frequency of 12.34 GHz, a return loss of 36 dB, and a 10 dB bandwidth of 7%. Kim and Yoon: Fabrication of three-dimensional millimeter-height structures. . . Downloaded From: http://nanolithography.spiedigitallibrary.org/ on 08/20/2015 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx Kim and Yoon: Fabrication of three-dimensional millimeter-height structures. . . Downloaded From: http://nanolithography.spiedigitallibrary.org/ on 08/20/2015 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx Kim and Yoon: Fabrication of three-dimensional millimeter-height structures. . . Downloaded From: http://nanolithography.spiedigitallibrary.org/ on 08/20/2015 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx Kim and Yoon: Fabrication of three-dimensional millimeter-height structures. . . Downloaded From: http://nanolithography.spiedigitallibrary.org/ on 08/20/2015 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx Kim and Yoon: Fabrication of three-dimensional millimeter-height structures. . . Downloaded From: http://nanolithography.spiedigitallibrary.org/ on 08/20/2015 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx Kim and Yoon: Fabrication of three-dimensional millimeter-height structures. . . Downloaded From: http://nanolithography.spiedigitallibrary.org/ on 08/20/2015 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx Kim and Yoon: Fabrication of three-dimensional millimeter-height structures. . . Downloaded From: http://nanolithography.spiedigitallibrary.org/ on 08/20/2015 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx

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“…The fabrication process consists of two steps: mask preparation and powderblasting machining: (a) LF55GN photosensitive elastomer (Macdermid, Cernay, France) is used as a masking material. More details of processing the photosensitive material can be found in previous work [30]. The elastomer presents a good erosion resistance to powder blasting [28].…”

Section: Methodsmentioning

confidence: 99%

Fabrication of microfluidic mixers with varying topography in glass using the powder-blasting process

Sayah

Thivolle

Parashar

et al. 2009

J. Micromech. Microeng.

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The powder-blasting method is used to fabricate structures with a three-dimensional topography in glass using elastomeric masks. The relation between the mask opening width and the erosion depth is exploited to fabricate microstructures with varying depth in a single micropatterning step. As an application, planar three-dimensional micro-mixers were fabricated, which consist of a repeating convergent microfluidic nozzle structure. Three different designs of the micro-mixers were considered. The mixing of co-flowing laminar streams results from the generation of multiple vortices at the exit of the different convergent nozzles.

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LF55GN Photosensitive Flexopolymer: A New Material for Ultrathick and High-Aspect-Ratio MEMS Fabrication

Cited by 6 publications

References 35 publications

Highly-compliant, microcable neuroelectrodes fabricated from thin-film gold and PDMS

Highly-compliant, microcable neuroelectrodes fabricated from thin-film gold and PDMS

Fabrication of three-dimensional millimeter-height structures using direct ultraviolet lithography on liquid-state photoresist for simple and fast manufacturing

Fabrication of microfluidic mixers with varying topography in glass using the powder-blasting process

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