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The aim of this study is to report the femtosecond laser with the characteristics of ultra-short pulse to develop the laser scribing technique of CIGS thin-film solar cells. In recent years, the P1 layer has always been scribed by long-pulse laser. The P2 and P3 layers are usually scribed by using high precision machine. To make a breakthrough in scribing processes for CIGS solar cell, the femtosecond laser scribing technique is proposed in this work. The wavelengths of femtosecond laser scribing in our work are in the range of infrared. The P1、P2 and P3 layers are scribed by using femtosecond laser processing at 1035 nm. In order to investigate the film, samples were scribed with the laser beam, and subsequently measured for film composition by X-ray fluorescence (EDS-XRF) spectroscopy. Optical microscopy was used to characterize the appearance of the scribed lines. A scanning electron microscope (SEM) and optical microscope (OM) were utilized to inspect the appearance of the laser treated films. The experimental results indicated that the substrates made of Mo (Molybdenum), CIGS and ZnO (ITO) can all be employed and the edges of metal device are especially suitable for femtosecond laser scribing. The scribing speed of femtosecond laser for Mo/glass substrate can reach as high as 2000 mm/s. Through the study, we got the best processes parameters of manufacturing. The results of this study indicated femtosecond laser can indeed improve the scribing quality in processing Mo material and CIGS thin-film as well.

This paper presents a novel method to create and integrate micro-machined devices and high aspect-ratio (height-to-width ratio) microstructures in which the microstructures are built up using multiple layers of photopolymer film and/or viscous solution. Very high aspect-ratio 2and 3-dimensional (2-D and 3-D) microstructures were constructed by stacking photo-imageable polymer films. Such films may be dry films applied by lamination or solution layers applied by bar coating, or doctor blade coating. Photolithography is used in both cases to define the microstructure. This additive process of thin-film micromachining facilitates high aspect-ratio microstructure fabrication. We have demonstrated structures of up to 12-layers comprising 2-D arrays of deep trenches (180 µm deep and 25 µm wide) and a 2-layer SU-8 micro-trench array with an aspect ratio up to 36 on glass substrates. Miniaturized structures of interconnected reservoirs as small as 50 µm x 50 µm x 15 µm (~38 pico liter storage capacity) are also being fabricated, along with a novel 5-layer microfluidic channel array and a vacuum-infiltration process for fluid manipulation. This method has the potential to create functional large-area micro-devices at low-cost and with increased device flexibility, durability, prototyping speed, and reduced process complexity for applications in optoelectronics, integrated detectors, and biodevices. The novel multi-layer photopolymer dry film and solution process also allows microstructures in micro-electro-mechanical systems (MEMS) to be built with ease and provides the functionality of MEMS integration with electronic devices and integrated circuits (ICs).

The dual beam Focused Ion Beam (FIB) system provides unique capabilities such as nanolithography and nanostructure fabrication using FIB chemical vapor deposition. The formation of electrical interconnects by FIB is of particular interest [1][2]. Equipped with nano-manipulators, the system allows us to directly measure the properties of nanostructures in-situ. In this paper, we present results on the in-situ electrical characterization of nanoscale test structures fabricated in the FIB.A FEI Dual Beam Nova NanoLab 200 equipped with five gas injection sources for deposition and etching was used for this study. This FIB is also equipped with a Zyvex F100 nano-manipulation stage, which includes four independent manipulators with 10 nm positioning resolution ( Fig. 1(a)). The four manipulators can be fitted with either sharp whisker probes for electrically probing samples or microgrippers for manipulating nanostructures as small as 10 nm. Fig. 1(b) shows gold contact pads used as electrical test structures for this study. A 100 nm thick gold thin film was deposited on insulating SiO 2 /Si substrates through a shadow mask to fabricate "dog-bone" looking structures (90µm×6µm).For electrical studies, a small gap of about 100 nm in width was first created by FIB Ga ion beam etching, as shown in Fig. 2(a). This provides electrical isolation between two-terminal contact structures. In-situ electrical I-V measurements were made on this structure with nano-manipulators connected to a Keithley 4200-SCS system. Fig. 2(b) shows I-V characteristics of the structure before and after the electrical isolation. The as-deposited gold contact pads exhibit a good electrical conductivity. The measured electrical conductivity of the electrically isolated structure fabricated by FIB is negligible and is well within the noise level of the measurement system (inset in Fig. 2(b)), indicating no significant metallic Ga contamination across the isolated contact structure. This also indicates that the substrate electrical conduction is negligible. Nanoscale interconnect structures were then fabricated by FIB CVD deposition of Pt, as shown in Fig. 3(a). The FIB deposited Pt nanointerconnect has a geometry of 500×200×200 nm 3 . The measured I-V characteristic of the Pt nanointerconnect is shown in Fig. 3(b), showing a good Ohmic behavior. The in-situ measured resistivity is approximately 220 µΩ⋅cm, which is higher than pure bulk Pt (10.6 µΩ⋅cm) [3]. However, the measured resistivity is consistent with previous studies [4]. Ex-situ electrical measurements were also done on the same nanointerconnect structure, resulting in minimal differences. Therefore, the measured resistivity is attributed to the FIB CVD process related defects such as co-deposited carbon contamination and disordered Pt microstructure. The contact resistance may also contribute to the total resistance. Our results demonstrate the feasibility of nano-patterning, deposition, and electrical probing all in-situ. This approach will work for complex interconnect integration of nanosc...

This study presents the design, simulation, fabrication and measurement of a microfluidic chip with micro cylindrical post array for separating particles. The structure of microfluidic chip is consisted of top glass, a micro channel with cylindrical post array, two Au end electrodes and bottom glass. Both in-line and staggered arrays of micro cylindrical posts were designed and made of SU-8 inside the micro channel by MEMS technology. The simulated results showed that the applied DC voltage at the end electrodes would generate a non-uniform electric fleld within the array of cylindrical posts, and particles would be attracted there. From the results of experiment, the minimum required DC voltages to drive micro particles flowing into the micro channel by electrokinetic effect were 15V and 30V, respectively, at the electrode spacing of 8mm and 25mm for both array types. Under the dielectrophoretic effect created by the non-uniform electric field, the latex particles could be concentrated around micro cylindrical posts with electric fleld intensity minima and separated from flowing fluid. This phenomenon is in agreement with the simulation.