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Graphical abstract Highlights • Surface-modified Fe 3 O 4 NPs and magnetic gelphotoresists were successfully prepared for TPP microfabrication. • Stability, UV photopolymerization effect and TPP properties of the magnetic gel photoresists were investigated. • 3D magnetic hydrogel microstructure with a size of ∼10 μm was successfully fabricated by TPP. • Obvious and reversible external-magnetic-field-driven bending behavior of the 3D hydrogel micro-nail was observed. Abstract In the biomedical micro-electromechanical systems (MEMS) field, the fabrication of three-dimensional (3D) magnetic hydrogel microdevices and microactuators with sizes smaller than 100 μm is difficult. In this paper, magnetic-field-driven 3D hydrogel microstructures were fabricated through four steps: the synthesis of surface-modified Fe 3 O 4 nanoparticles (Fe 3 O 4 NPs), the preparation of a magnetic gel photoresist, two-photon polymerization microfabrication, and a solvent-exchange process. For the preparation of a stable magnetic gel photoresist, surface-modified Fe 3 O 4 NPs with an average size of 7.8 nm were synthetized and well dispersed in gel photoresist. The magnetic gel photoresist exhibited a good UV photopolymerization effect, and a magnetic-field-driven macroscopic hydrogel was prepared. The two-photon polymerization properties of gel photoresists with various Fe 3 O 4 NP contents were investigated in detail, and the minimum width of fabricated lines reached 106 nm for the photoresist with 0.32 wt% Fe 3 O 4 NPs. Three hydrogel microstructures—the Qingdao University logo, a magnetically actuated micro-rod, and a magnetically actuated micro-nail—were successfully fabricated using a gel photoresist with 0.96 wt% Fe 3 O 4 NPs. Importantly, obvious and reversible external-magnetic-field-driven bending behavior of the 3D hydrogel micro-nail with a size of 10 μm was observed. [ABSTRACT FROM AUTHOR]

A novel conical nozzle fabrication method for piezoelectric inkjet printhead is proposed based on the microelectromechanical system technology. By optimizing the exposure gap, exposure dose, postexposure bake (PEB), and development time, the SU-8 conical nozzle was fabricated. After thermal bonding with an open chamber, the piezoelectric inkjet printhead chamber was formed. The results show that the optimum SU-8 conical nozzle can be fabricated by applying exposure dose of 105 mJ/cm2, exposure gap of 50 µm, PEB temperature of 65°C, PEB time of 10 min, and development time of 210 s. The final size of optimum conical nozzle is the large aperture of 30.46 ± 1.17 µm, small aperture of 20.34 ± 1.42 µm, and nozzle height of 45.38 ± 1.02 µm. [ABSTRACT FROM AUTHOR]

In deep x-ray lithography (DXRL), synchrotron radiation is applied to transfer absorber patterns on an x-ray mask into thick photoresist to generate high quality microstructures. Fabrication of the required x-ray masks is a demanding process sequence and constitutes a bottleneck in DXRL technology. Polymer-based mask membranes offer many benefits during mask fabrication and operation, but usually suffer from large thermal distortions during x-ray exposure. These are due to the low thermal conductivity of most polymers (approximately 0.2W/m K), which results in ineffi- cient heat transfer to the cooled areas around mask and substrate. The power tuning capabilities at the Synchrotron Laboratory for Micro and Nano Devices beamline, Canadian Light Source, however, allow the beam power to be adjusted and consequently limit thermal distortions. In this study, x-ray masks based on 30 lm thick polyimide membranes are studied. Numerical simulations of the thermal and thermoelastic behavior were performed using the software package ANSYS R14.5. The beam power input parameters were calculated with the software LEX-D. For experimental verification, a process to fabricate simple test masks was developed. The polymer membranes were processed on stainless steel sacrificial wafers and were patterned with 80 lm thick nickel absorbers in two macroscopic layouts. Five chromel/alumel (K-type) thermocouples where then bonded to the absorbers to measure the heat distribution. The measurements generally validated the numerical results. The simulated thermal distributions consistently overestimate the experimental values by approximately 4-6 K, which is mainly attributed to uncertainties in the experimental proximity gap settings. The thermal simulation results indicate that the dominant heating mechanism of the resist is conduction: Energy absorbed in the mask absorbers is conducted through the helium gas in the proximity gap to the nonexposed poly(methyl methacrylate) (PMMA) areas and the substrate (cooled to 18 °C). For 500 lm thick PMMA resist, exposed with a synchrotron beam power of 19.6 W, maximum temperatures in the mask are 31.0 and 25.8 °C in the resist below. Maximum single-axis resist deformations in the mask plane amount to 4.12 lm. At 250 lm resist thickness, the observed temperatures are only 25.4 °C in the mask and 22.3 °C in the resist, with maximum mask plane deformations of about 2.3 lm. Integrated over the entire absorber size of 60 mm, these deformations roughly double. Local structure accuracy results were obtained by measuring distortions in a micropatterned polyimide mask. Deformations verify simulation results, vary with the position on the layout, and scale with the incident beam power. At 3.3W incident beam power, typical deformations around 1-1.5 lm and maximum deformations of 2.3 lm were measured in 100 lm thick resist. [ABSTRACT FROM AUTHOR]

We show the design for a laser scanning microscopy defect detection system based upon the idea that the light can reflect off a photoresist-laden fused-silica sample containing defects, allowing height and depth information to be obtained through changes in light intensity. Image registration using predefined points is employed. Image processing techniques involving median and deconvolution filtering are used. Results show that the 2.1-µm resolution of these defects is obtainable, and receiver operating characteristic curves are used for quantifying results. Discriminabilities of 0.73 are achieved. Preliminary results for larger-array patterns through stitching processes are also shown. [ABSTRACT FROM AUTHOR]

The development of new photoresist materials for multi-lithography applications is crucial but a challenging task for semiconductor industries. During the last few decades, given the need for new resists to meet the requirements of semiconductor industries, several research groups have developed different resist materials for specific lithography applications. In this context, we have successfully synthesized a new molecular non-chemically amplified resist (n-CAR) (C3) based on the functionalization of aromatic hydroxyl core (4,4′-(9H-fluorene-9,9-diyl)diphenol) with radiation sensitive sulfonium triflates for various lithography applications. While, micron scale features have been developed using i-line (365 nm) and DUVL (254 nm) exposure tools, electron beam studies on C3 thin films enabled us to pattern 20 nm line features with L/3S (line/space) characteristics on the silicon substrate. The sensitivity and contrast were calculated from the contrast curve analysis as 280 µC cm−2 and 0.025 respectively. Being an important parameter for any newly developed resists, the line edge roughness (LER) of 30 nm (L/5S) features were calculated, using SUMMIT metrology package, to be 3.66  ±  0.3 nm and found to be within the acceptable range. AFM analysis further confirmed 20 nm line width with smooth pattern wall. No deformation of patterned features was observed during AFM analysis which indicated good adhesion property between patterned resists and silicon substrates. [ABSTRACT FROM AUTHOR]