Takao Kameda

Nanoimprint lithography using disposable biomass template

A novel nanoimprint lithography process using disposable biomass template having gas permeability was investigated. It was found that a disposable biomass template derived from cellulose materials shows an excellent gas permeability and decreases transcriptional defects in conventional templates such as quartz, PMDS, DLC that have no gas permeability. We believe that outgasses from imprinted materials are easily removed through the template. The approach to use a cellulose for template material is suitable as the next generation of clean separation technology. It is expected to be one of the defect-less thermal nanoimprint lithographic technologies. It is also expected that volatile materials and solvent including materials become available that often create defects and peelings in conventional temples that have no gas permeability.

Utilization of gas permeable metal plate for the purpose of reduction of transfer defect in MEMS electronic device

The electronic substrate used for the MEMS device is finely processed, and imprint lithography is often used as a processing method. However, in the printing process, gas is caught in the molding material, and transfer failure frequently occurs. Therefore, in this study, a gas permeable metal plate with a gas permeable structure inside was fabricated and imprinted on a material to be transferred containing 50% of volatile material. As a result, no gas pool was observed and imprinting was possible without defective transfer. This not only prevents entrainment of gas at the time of imprinting, but also a transfer material containing a volatile solvent can be used as a material to be transferred. It is greatly expected that the developed gas permeable metal plate becomes a material necessary for MEMS device processing.

Internal structure of metal material with gas permeability function related to MEMS devices

MEMS technology is incorporated into various devices (automobiles, digital cameras, optical devices) indispensable for our daily lives. Semiconductor manufacturing process technology such as photolithography method and ion beam method is mainly used for micropatterning necessary for MEMS and microfabrication of diffraction grating. In photolithography, many transfer defects caused by gas are generated. Therefore, a metal plate having gas permeability was prepared with a 3D printer, and the surface and internal structure of the metal plate was evaluated. Further, the porosity of the metal plate was calculated by measuring the size and weight of the produced metal plate. As a result, it was confirmed that there were numerous holes in the inside of the metallic material, and it was confirmed that the hole having the role of permeating the gas and the hole having the role of temporarily preserving the gas. Furthermore, it was also confirmed that the porosity of the metal plate is about 10%. Metallic materials with gas permeability can be expected to be materials required for MEMS device processing.

Temperature dependence of viscoelasticity of crystalline cellulose with different molecular weights added to silicone elastomer

Silicone elastomers ( polydimethylsiloxane _ PDMS) are widely used in the field of imprint lithography and microcontactprinting (μCP). When performing microcontactprinting, the mechanical properties of the PCMS as a base material have a great influence on the performance of the device. Cellulose nanofibers having features of high strength, high elasticity and low coefficient of linear expansion have attracted attention in recent years due to their characteristics. Therefore, three types of crystalline cellulose having different molecular weights were added to PDMS to prepare a composite material, and dynamic viscoelasticity was measured using a rheometer. The PDMS with the highest molecular weight crystalline cellulose added exhibited smaller storage modulus than PDMS with other molecular weight added in all temperature ranges. Furthermore, when comparing PDMS to which crystalline cellulose was added and PDMS which is not added, the storage modulus of PDMS to which cellulose was added in the low temperature region was higher than that of PDMS to which it was not added, but it was reversed in the high temperature region It was a result. When used in a low temperature range (less than 150 ° C.), it can be said that cellulose can function as a reinforcing material for PDMS.

Temperature dependency of mechanical properties for crystalline cellulose added to silicone elastomer

A chemical cross-linked transparent film was got by a silicon compound to crystalline cellulose. Temperature dependency for the elasticity modulus of a provided film was measured. The shear elastic modulus was obtained the value of 2 x 106 [Pa] at room temperature. The sample decreases in 190 [deg. C] for the elasticity modulus at the room temperature as 60%, but approximately 10% recover when temperature rises up to 200 [deg. C] or more.

High resolution patterning of ultraviolet cross-linked resins using gas permeable mold derived from cellulose in nanoimprint lithography

A cellulose-based gas permeable mold having thermal crosslinking group for nanoimprint lithography has been developed to prevent transcriptional defects by volatile solvents from nanoimprinting materials. 3 wt.% of thermal initiator was required for producing the cellulose-based gas permeable mold. The void on 10 μm line structure of imprinted UV crosslinked resin with acetone as volatile solvents in nanoimprint lithography process using non-gas permeable mold was significantly removed using the cellulose-based gas permeable mold due to its high oxygen gas permeability. The cellulosebased gas permeable mold allows the employment of solvent including imprinting materials such as compounds and alloy particle.

Production and evaluation of measuring equipment for share viscosity of polymer melts included nanofiller with injection molding machine

Shear viscosity measurement device was produced to evaluate the injection molding workability for high-performance resins. Observation was possible in shear rate from 10 to 10000 [1/sec] that were higher than rotary rheometer by measuring with a plasticization cylinder of the injection molding machine. The result of measurements extrapolated result of a measurement of the rotary rheometer.

Approach of UV nanoimprint lithography using template with gas-permeable and gaseous adsorption for reduction of air-trapping issue

In this paper, we studied a novel approach, UV nanoimprint lithography using glucose-based template with gaspermeable and gaseous adsorption for reduction of air-trapping issue. The air-trapping issue in UV nanoimprint lithography resist is a cause of pattern failure in resist or UV curable materials. The results of 180 nm dense line patterning of UV curable patterning materials containing acetone in UV nanoimprint lithography using glucose-based template with gas-permeable and gaseous adsorption were effected to reduce the pattern failure as compared with that of the poly(dimethylsiloxane) without gas-permeable and gaseous adsorption as the reference. The proposed UV nanoimprint lithography using glucose-based template with gas-permeable and gaseous adsorption is one of the most promising processes ready to be investigated for mass-production of photomask applications.

Evaluation of the properties of the permeability film material using cellulose nanofibers

In order to enable the large-area patterning of micro-fabrication, constant intensity will be required to the mold material. Then, we have deposited the sample was subjected to a chemical synthesis in different hydroxy propyl cellulose (HPC) viscosity, we evaluated its transferability and optical transparency. As a result of gel permeation chromatography system (GPC) measurement, we confirmed that high viscosity sample was high molecular weight in the two types of HPC with different viscosity. Further, we will produce a film with the sample, we evaluated the transfer and light permeability of the film. In the evaluation of transfer properties, Regardless of the level of the viscosity of the HPC of the main raw material, the shape of the master silicon template(5μm line and space) had been transferred to the HPC template. Moreover in the evaluation of optical transparency, HPC template had about 60% of the light transmittance in the 365nm wavelength. The sample have a possibility to improve the strength to be polymerized, and a high optical transparency, it used in this study is expected to be a mold material for UV nano-imprint lithography.