UV Lithography and Molding Fabrication of Ultrathick Micrometallic Structures Using a KMPR Photoresist

Shin, Youngmin; Gamzina, Diana; Barnett, Larry R.; Yaghmaie, Frank; Baig, Anisullah; Luhmann, Neville C.

doi:10.1109/jmems.2010.2045880

Cited by 41 publications

(15 citation statements)

References 17 publications

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“…The selection considerations of the photoresist in the second lithography step are threefold: (1) must be a negative photoresist; (2) the resist thickness should well exceed the thickness difference of the dual-height structures and, (3) for some applications where a fixed gap size is desired, a straight resist wall-profile is needed. A chemically amplified thick negative photoresist KMPR with HAR capability and straight wall-profile, has been reported as an SU8 alternative for UV LIGA process with improved removability [9,10]. For demonstration purpose, KMPR 1050 (MicroChem) with 100 µm in thickness was used for the second lithography step.…”

Section: Second Lithography Process For High-aspect-ratio (Har) Moldsmentioning

confidence: 99%

A single mask process for the realization of fully-isolated, dual-height MEMS metallic structures separated by narrow gaps

Kim

Allen

2018

J. Micromech. Microeng.

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Multi-height metallic structures are of importance for various MEMS applications, including master molds for creating 3D structures by nanoimprint lithography, or realizing vertically displaced electrodes for out-of-plane electrostatic actuators. Normally these types of multi-height structures require a multi-mask process with increased fabrication complexity. In this work, a fabrication technology is presented in which fully-isolated, dual-height MEMS metallic structures separated by narrow gaps can be realized using a self-aligned, single-mask process. The main scheme of this proposed process is through-mold electrodeposition, where two photoresist mold fabrication steps and two electrodeposition steps are sequentially implemented to define the thinner and thicker structures in the dual-height configuration. The process relies on two selfaligned steps enabled by the electrodeposited thinner structures: a wet-etching of the seed layer utilizing the thinner structure as an etch-mask to electrically isolate the thinner and the thicker structures, and a backside UV lithography utilizing the thinner structure as a lithographic mask to create a high-aspect-ratio mold for the thicker structure through-mold electrodeposition. The latter step requires the metallic structures to be fabricated on a transparent substrate. Test structures with differences in aspect ratio are demonstrated to showcase the capability of the process.

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Section: Second Lithography Process For High-aspect-ratio (Har) Moldsmentioning

confidence: 99%

A single mask process for the realization of fully-isolated, dual-height MEMS metallic structures separated by narrow gaps

Kim

Allen

2018

J. Micromech. Microeng.

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“…This photoresist layer is typically ∼10 μm thicker than the height of the features, i.e., ∼160 μm. To accomplish this, KMPR 1050 (epoxybased negative-tone photoresist) is spun onto the wafer at 1200 rpm for 10 s. 10,11 The wafer is then baked at 100 • C on a hot plate for 2 h and left in ambient conditions for 12 h to allow the solvents to out-gas from the resist. The wafer is baked again on the hotplate at 100 • C for 15 min to further drive out residual solvent.…”

Section: Fabricationmentioning

confidence: 99%

“…To achieve a proximity that is relevant to ions used for quantum information, i.e., an ion distance, h 100 μm, from the surfaces, the trap should have features on this scale. In order to fabricate a stylus trap with features of 100 μm, we utilized UV-LIGA (a German acronym for lithography, electroplating, and molding) technology, [8][9][10][11][12] i.e., UV photolithograpy with a thick resist and subsequent metal electroforming with the use of electrodeposition. Using this technique, we have fabricated traps that consist of 150 μm tall structures (see Figs.…”

Section: Introductionmentioning

confidence: 99%

Micro-fabricated stylus ion trap

Lew

McKay

Baca

et al. 2013

Review of Scientific Instruments

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An electroformed, three-dimensional stylus Paul trap was designed to confine a single atomic ion for use as a sensor to probe the electric-field noise of proximate surfaces. The trap was microfabricated with the UV-LIGA technique to reduce the distance of the ion from the surface of interest. We detail the fabrication process used to produce a 150 μm tall stylus trap with feature sizes of 40 μm. We confined single, laser-cooled, (25)Mg(+) ions with lifetimes greater than 2 h above the stylus trap in an ultra-high-vacuum environment. After cooling a motional mode of the ion at 4 MHz close to its ground state ( = 0.34 ± 0.07), the heating rate of the trap was measured with Raman sideband spectroscopy to be 387 ± 15 quanta/s at an ion height of 62 μm above the stylus electrodes.

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“…This sheet beam topology is particularly of interest in the millimeter wave band devices at frequencies >100 GHz where the familiar P $ f 2 scaling no longer holds with a dramatic decrease in power observed in the "THz gap" that lies between the electronics and photonics areas of research. 9,10 In addition to the ability to transport higher power for reasonably efficient beam-wave interaction, the planar structures are relatively easier to fabricate using unconventional/MEMS fabrication schemes like LIGA, 11,12 EDM machining, 13,14 Si DRIE, 4 and nano-CNC milling. 11,12,15 This paper presents the RF transmission measurements (cold test) results of the Sheet Beam TWTA in the 170 GHz-270 GHz frequency range that is fabricated by state-of-the-art nano CNC-milling process 16 and diffusion bonded in a three layer topology.…”

Section: Introductionmentioning

confidence: 99%

0.22 THz wideband sheet electron beam traveling wave tube amplifier: Cold test measurements and beam wave interaction analysis

et al. 2012

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Measurements of parallel electron velocity distributions using whistler wave absorption Rev. Sci. Instrum. 83, 083503 (2012) HELIOS: A helium line-ratio spectral-monitoring diagnostic used to generate high resolution profiles near the ion cyclotron resonant heating antenna on TEXTOR Rev. Sci. Instrum. 83, 10D722 (2012) Microwave Doppler reflectometer system in LHD Rev. Sci. Instrum. 83, 10E322 (2012) Design of a millimeter-wave polarimeter for NSTX-Upgrade and initial test on DIII-D Rev. Sci. Instrum. 83, 10E321 (2012) Design of the reflective optics for Tore Supra ECEI system Rev. Sci. Instrum. 83, 10E318 (2012) Additional information on Phys. PlasmasIn this paper, we describe micro-fabrication, RF measurements, and particle-in-cell (PIC) simulation modeling analysis of the 0.22 THz double-vane half period staggered traveling wave tube amplifier (TWTA) circuit. The TWTA slow wave structure comprised of two sections separated by two sever ports loaded by loss material, with integrated broadband input/output couplers. The micro-metallic structures were fabricated using nano-CNC milling and diffusion bonded in a three layer process. The 3D optical microscopy and SEM analysis showed that the fabrication error was within 2-3 lm and surface roughness was measured within 30-50 nm. The RF measurements were conducted with an Agilent PNA-X network analyzer employing WR5.1 T/R modules with a frequency range of 178-228 GHz. The in-band insertion loss (S 21 ) for both the short section and long section (separated by a sever) was measured as $À5 dB while the return loss was generally around $À15 dB or better. The measurements matched well with the S-matrix simulation analysis that predicted a 3 dB bandwidth of $45 GHz with an operating frequency at 220 GHz. However, the measured S 21 was $3 dB less than the design values, and is attributed to surface roughness and alignment issues. The confirmation measurements were conducted over the full frequency band up to 270 GHz employing a backward wave oscillator (BWO) scalar network analyzer setup employing a BWO in the frequency range 190 GHz-270 GHz. PIC simulations were conducted for the realistic TWT output power performance analysis with incorporation of corner radius of 127 lm, which is inevitably induced by nano-machining. Furthermore, the S 21 value in both sections of the TWT structure was reduced to correspond to the measurements by using a degraded conductivity of 10% International Annealed Copper Standard. At 220 GHz, for an elliptic sheet electron beam of 20 kV and 0.25 A, the average output power of the tube was predicted to be reduced from 90 W (for ideal conductivity/design Sparameters) to 70 W (for the measured S-parameters/inferred conductivity) for an average input power of 50 mW. The gain of the tube remains reasonable: $31.4 dB with an electronic efficiency of $1.4%. The same analysis was also conducted for several frequencies between 190 GHz-260 GHz. This detailed realistic PIC analysis demonstrated that this nano-machined TWT circuit has slightly reduced...

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UV Lithography and Molding Fabrication of Ultrathick Micrometallic Structures Using a KMPR Photoresist

Cited by 41 publications

References 17 publications

A single mask process for the realization of fully-isolated, dual-height MEMS metallic structures separated by narrow gaps

A single mask process for the realization of fully-isolated, dual-height MEMS metallic structures separated by narrow gaps

Micro-fabricated stylus ion trap

0.22 THz wideband sheet electron beam traveling wave tube amplifier: Cold test measurements and beam wave interaction analysis

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