Yung-Jin Weng

Optimizations of the Processing Parameters of High-Performance Engineering Plastic in Injection Molding

Thin-wall injection molding parts have the shrinkage distortion problem, this is mainly caused by the setting of processing parameters. Gray relational analysis and Taguchi method were applied to obtain the combination of processing parameters that could produce the product with optimal multiple quality characteristics. We used gray relational analysis to solve the single quality characteristic problem of Taguchi method and used the response graph of gray relational analysis to receive the optimal processing parameters combinations, which would produce the product with multiple quality characteristics. Finally, the confirmation experiment proved the reliability and reproducibility of this experiment with 95% confidence interval.

Technological Development of Advanced Asymmetric Magnetic Soft Mold Micro-Imprint Lithography

This study proposed an advanced micro-imprint lithography (MIL), which integrates electromagnetic field-aided hot embossing and PDMS asymmetric magnetic flexible soft mold imprinting techniques, to imprint and replicate the microlens array structure. It is similar to the continuous grayscale technique; however, it is smoother than the structural form defined by the semi-conductor grayscale mask technique, and the process is simpler with lower costs, making it a good alternative for imprinting techniques and applications. This study also employed prescale films to measure and discuss the distribution of imprinting force on asymmetric magnetic soft molds. The results indicated that the magnetic soft mold and the substrate surface can be fully contacted. Since the magnetic powder reveals a skewed distribution, the test results of prescale film indicated that color depth is related to the concavo-convex of magnetic powder. Thus, the depth and accuracy of structural molding can be controlled in advance by casting the inclining platform. Finally, the SEM observation showed that if an inclining platform is used for composite magnetic PDMS casting, the microlens array asymmetric magnetic soft mold structure, which is complementary to it, could be obtained. The asymmetric magnetic soft mold was applied together with electromagnetic field-aided hot embossing equipment to imprint and replicate different continuous and smooth microlens array structures with foreseeable depth.

Development and Study of Applications Combining Nanopowder Imprint Lithography and Array-Type UV-Curing Technology for Micro-Lens Molding

This study developed creative imprinting technology, combining nano-imprint lithography and array-type UV-curing technology. It used nanopowders as the method to transmit imprint force, and integrated technical features, such as soft lithography, light-curing resistant and gas-assisted imprint technology, in order to study the development of technological processes of micro-lens array manufacturing, and mature the application and technology of nano-imprinting. According to research results, SUS 304 stainless steel sheet with a micro-hole array could be smoothly fabricated into an original micro-lens array mold upon gas-assisted micro-hot embossing. At the same time, a micro-lens array structure with a complementary external form could be precisely remolded and reproduced by PDMS. Complete molding of micro-lens could be effectively achieved by combining imprints of gas-assisted lithography developed in this study, and even UV-NIL. The effective imprinting area and reproducibility of transfer printing could be greatly improved when a micro-lens contacts perfectly with a substrate surface. Moreover, since PDMS soft molds have short remolding times, and are easily feathered during manufacturing, production costs could be effectively reduced through features such as, low surface free energy, resistant to adhering to the mold during imprinting, and collocation of gas-assisted nanopowder imprinting of micro-structural processes.

Electromagnetic Field-Aided Magnetic Soft Mold Reverse Imprinting Technology Applied in Microstructure Replication

This paper proposes an advanced microstructure embossing replication technology that combines an electromagnetic-field-aided magnetic soft mold and a reverse imprinting technology to replicate microstructure. The main advantage of this technology is low pressure, low cost, and quick and easy forming. The entire imprinting process can be completed at room temperature using a ultraviolet (UV) curing technique. This study applied a compound casting technique to fabricate a magnetic poly(dimethylsiloxane) (PDMS) soft mold, with an electromagnetic chuck for even imprinting pressure, and reverse imprinting molding technology. Microstructure cavity of the mold was fully filled with photoresist before imprint replication, and improved microstructure transfer ratio. Examination of the results showed that, the magnetic PDMS soft mold integrated electromagnetic-field-aided reverse imprinting process developed by this study, can successfully replicate microstructure at room temperature, low pressure, and avoid deformation and residual stress problems due to heating and cooling.

Evaluation of the Nanofabrication and Corrosion on Copper by In-situ ECAFM

This study used the Electrochemical Atomic Force Microscopy (ECAFM) in Contact Mode to discuss the nanofabrication and corrosion of pure Cu in an environment with DI water and applied voltage. It also observed the morphological changes of nanometric surfaces of pure Cu. The results showed that in the environment of DI water and applied voltage, the silicon probe of ECAFM would have a nanometric cutting effect at an early stage on a pure Cu surface, thus producing a visible hole. However, such cutting effects would be diminished with time when electrochemical machining is prolonged, due to oxidation effects. If the EC-AFM probe does not continuously scan the pure Cu surface areas, the protrusions on the surface would extend due to oxidation.

Fabrication of Optical Waveguide Devices Using Electromagnetic Assisted Nanoimprinting

A creative technology was used in this research. Using the PDMS flexible mold magnetic powder method to transmit imprinting, and by combining the special characteristics of the soft lithography, polymethylmethacrylate (PMMA), and electromagnetic Plate uniform control pressing technology, researching the use of magnetic flexible mold imprinting technology to produce the optical waveguide devices, so as to allow the usage and the technology of micro hot embossing or nanoimprinting more mature.

A Discussion on the Development of SCF-CO2 Hot Embossing Molding Technology and Replication Moldability

This study developed carbon dioxide (CO2)-assisted hot embossing molding technology using the penetration of SCF (supercritical fluid), as generated by CO2 in a high pressure process, into the high polymer plastic substrate in order to realize the plasticization phenomenon. At the glass transition temperature (Tg), microstructure array elements were molded by hot embossing replication, and the optical effects of the formed microstructure were discussed. This study first developed the SCF hot embossing system equipment by evenly infiltrating the plastic substrate through the SCF phenomenon generated by CO2 under high pressure. Using the characteristics of the CO2-aided uniform imprinting technology, this study discussed the microstructure replication moldability and optical effects of the microstructure at the Tg temperature. The results suggested that the SCF hot embossing system proposed in this study can successfully transliterate the microstructure onto the photo-resist at Tg temperature. This study also tested and discussed the replication moldability and optical effects of the structure.

A Novel Magnetic Nickel Mold Combined Nano-Particle Fluid Electromagnetism Imprinting on Replicating Microstructures

This study proposes a novel technology using nano-particle fluid electromagnetism to control the direct hot imprint resist of nickel mold. combining the present gas-assisted nanoparticle hot imprint molding technology, electroforming technology, and self-designed heatable electromagnetic plate for even control and progressive pressuring technology, this study used electromagnetic nickel mold direct hot imprint to replicate micro structures, in order to make the molding technology and application of micro nanoimprint more mature. This study first used gas-assisted nanoparticle hot embossing method to replicate structures of microlens of original silicon molds on PC, so as to obtain complementary structural patterns. This PC film with structures of microlens is cast into nickel molds by electroforming. This nickel mold was used as the mold for magnetic embossing to imprint hot plastic PMMA.The result showed that through gas-assisted nanoparticle hot embossing molding, casting and component magnetic PDMS soft mold casting, molds of high costs and complicated production process can be massively replicated, and the replication precision is good. Hot gas embossing PDMS film and the surface of base materials can achieve even pressure and conformal contact, thus significantly improving the effective imprint area and imprintability. Through electroforming, casting duration of magnetic nickel molds can be shortened and costs can be effectively lowered. Moreover, electromagnetic plate was used to evenly control the direct hot pressure imprint resist, which is an advantage of the production process of micro structures.

Fabrication of Ridge Waveguide Microstructure Using Vacuum-assisted Micromolding Technology

Limited by light source wavelength and light diffraction, nanostructure fabrication is tough, but it needs multiple special and expensive processes (e.g.: E-beam). The common problems are complex and slow processing, expensive manufacturing equipment and material, and it is very unsuitable for mass production; therefore, it’s of utmost importance to develop a nanoscale, high resolution and cost efficient next generation semiconductor process. This study integrated PDMS soft mold, photo resist(SU-8 2035) and vacuum pumping equipment, as well as researched and developed a vacuum-assisted photo resistant microstructure filling technique, and combined soft mold to fabricate waveguide microstructure. Conformal contact was obtained between PDMS soft mold and substrate surface, with low surface free energy, and resistance of sticking to resist in filling.Vacuum equipment was used to enable compact and complete resistant filling, and it can not only greatly increase the effective filling area, but, without residue after filling. There is no need for post treatment removing of the residual layer; it can well lower cost and reduce process time, so that the microstructure component manufacturing technique and application can be more mature.

Fabrication of Microlens Arrays by Using Nano-Particle Fluid Imprinting Technology

In this study, we look into an innovative technology which utilizes nano-particles as a medium for imprinting. This technology integrates the advantages of soft lithography, photo-cure resist, and gas assisted imprinting. We try to produce micro-lens arrays by gas-assisted nano-particles based soft mould imprinting on photo-cure resists. It helps the application and technology of nano-imprinting becoming more sophisticated. We find that PDMS can be used to precisely replicate micro-to-nano-meter level micro-structures. Together with nano-particles and well-proportioned gas pressure, we can construct a perfect shape of micro-structures and achieve a conformal contact with the surface of base material. It increases the effective imprinting area significantly and improves the replication capability of the transfer. Meanwhile, the PDMS soft mould is easy for production and fast in replication, which reduces the cost remarkably. Furthermore, it has a low surface free energy and low viscosity to the resists. Integrating gas assisted nano-particles imprinting can be a great advantage in the process of micro-structure.