Negative photoresists for optical lithography

Shaw, Jane M.; Gelorme, Jeffrey D.; LaBianca, N.; Conley, Will; Holmes, Steven J.

doi:10.1147/rd.411.0081

Cited by 317 publications

(233 citation statements)

References 23 publications

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“…Previous works have reported a 0.22 Poisson ratio for the SU-8 polymer [12], assuming then a similar membrane behavior to expression (1) when a real pressure is applied. In order to verify the theoretical analysis before determining the appropriate dimensions for the membrane, software tool Coventorware was used to simulate the phenomenon involved in valve operation.…”

Section: Mechanical Actuationmentioning

confidence: 54%

A novel single-use SU-8 microvalve for pressure-driven microfluidic applications

Quero¹

2009

J. Micromech. Microeng.

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Abstract.A novel microfluidic single-use valve for fluid injection and extraction in pressuredriven applications is presented in this paper. The device consists in a thin SU-8 membrane crossed by a resistor that withstands a mechanical stress induced by a pressure difference. When the resistor heats up the membrane, the SU-8 fracture strength drastically decreases causing the valve activation. This device has been designed, fabricated using inexpensive SU-8 and Printed Circuit Board technologies, and finally characterized. The hybrid thermalmechanical microvalve operation principle has been demonstrated and experimental results have shown the device characteristics and performance. Specifically, this design was functional at pressures of 0.8 MPa and opened in less than 3.2 seconds with an applied power of 280 mW. The simple fabrication process and the absence of moving mechanical parts have made the valve suitable for large-scale integration in Lab-on-Chip microfluidic platforms.

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Section: Mechanical Actuationmentioning

confidence: 54%

A novel single-use SU-8 microvalve for pressure-driven microfluidic applications

Quero¹

2009

J. Micromech. Microeng.

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“…However, SU-8 is an epoxy-based negative photoresist, which consists of epoxies and photoinitiators (triarylsulfonium salts). 28 After exposure, SU-8 is polymerized by cationic photopolymerization processes, which releases hexafluoroantimonate complexes (SbF 6 2 ) from photoinitiators for further polymerization processes. In our experiment, the SU-8 is exposed by a 500% over dosage, meaning most of the photoinitiator is reacted, and then generates large amount of SbF 6 2 .…”

Section: Principle and Fundamental Studies Sessile Drop Experimentsmentioning

confidence: 99%

Asymmetric electrowetting—moving droplets by a square wave

et al. 2007

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Here droplet oscillation and continuous pumping are demonstrated by asymmetric electrowetting on an open surface with embedded electrodes powered by a square wave electrical signal without control circuits. The polarity effect of electrowetting on an SU-8 and Teflon coated electrode is investigated, and it is found that the h-V (contact angle-applied voltage) curve is asymmetric along the V = 0 axis by sessile drop and coplanar electrode experiments. A systematic deviation of measured contact angles from the theoretical ones is observed when the electrode beneath the droplet is negatively biased. In the sessile drop experiment, up to a 10u increment of contact angle is measured on a negatively biased electrode. In addition, a coplanar electrode experiment is designed to examine the contact angles at the same applied potential but opposite polarities on two sides of one droplet at the same time. The design of the coplanar electrodes is then expanded to oscillate and transport droplets on square-wave-powered symmetric (square) and asymmetric (polygon) electrodes to demonstrate manipulation capability on an open surface. The frequency of oscillation and the speed of transportation are determined by the frequency of the applied square wave and the pitch of the electrodes. Droplets with different volumes are tested by square waves of varied frequencies and amplitudes. The 1.0 ml droplet is successfully transported on a device with a loop of 24 electrodes continuously at a speed up to 23.6 mm s 21 when a 9 Hz square wave is applied.

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“…[1][2][3] Commercially available formulations (Shell Chemical, MicroChem) provide a macromonomer 1 (Scheme 1) dissolved in γ-butyrolactone at different concentrations. 1 These different formulations are spin-coated onto a wide range of substrates giving raise to a range of film thicknesses in the range 1 to 100µm, depending on the viscosity of the original solution and the spin speed. [1][2][3] They also contain a photoacid to initiate polymerization of the epoxide groups upon UV exposure.…”

Section: Introductionmentioning

confidence: 99%

“…1 These different formulations are spin-coated onto a wide range of substrates giving raise to a range of film thicknesses in the range 1 to 100µm, depending on the viscosity of the original solution and the spin speed. [1][2][3] They also contain a photoacid to initiate polymerization of the epoxide groups upon UV exposure. [1][2][3] The resulting polymerized resin is a highly crosslinked polymer, the hardness of which depends on the time and energy of the UV exposure and post-exposure baking times and temperatures.…”

Section: Introductionmentioning

confidence: 99%

Multistep Synthesis on SU-8: Combining Microfabrication and Solid-Phase Chemistry on a Single Material

et al. 2007

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SU-8 is an epoxy-novolac resin and a well-established negative photoresist for microfabrication and microengineering. The photopolymerized resist is an extremely highly crosslinked polymer showing outstanding chemical and physical robustness with residual surface epoxy groups amenable for chemical functionalization. In this paper we describe, for the first time, the preparation and surface modification of SU-8 particles shaped as microbars, the attachment of appropriate linkers, and the successful application of these particles to multistep solid-phase synthesis leading to oligonucleotides and peptides attached in an unambiguous manner to the support surface.

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Negative photoresists for optical lithography

Cited by 317 publications

References 23 publications

A novel single-use SU-8 microvalve for pressure-driven microfluidic applications

A novel single-use SU-8 microvalve for pressure-driven microfluidic applications

Asymmetric electrowetting—moving droplets by a square wave

Multistep Synthesis on SU-8: Combining Microfabrication and Solid-Phase Chemistry on a Single Material

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