Atsushi Sekiguchi

Electron Beam Lithography Using Highly Sensitive Negative Type of Plant-Based Resist Material Derived from Biomass on Hardmask Layer

We investigated electron beam (EB) lithography using a novel highly sensitive negative type of plant-based resist material derived from biomass on a hardmask layer for trilayer processes. The chemical design concept for using the plant-based resist material with glucose and dextrin derivatives was first demonstrated in the EB lithography. The 1 µm line patterning images with highly efficient crosslinking properties and low film thickness shrinkage were provided under specific process conditions of EB lithography. The results shown reveal that the alpha-linked disaccharide formed by a 1,1-glucoside bond between two glucose units in dextrin derivatives was an important factor in controlling the highly sensitive EB patterning and developer properties.

Ecofriendly antiglare film derived from biomass using ultraviolet curing nanoimprint lithography for high-definition display

Abstract. Nanopatterning of an ecofriendly antiglare film derived from biomass using an ultraviolet curing nanoimprint lithography is reported. Developed sugar-related organic compounds with liquid glucose and trehalose derivatives derived from biomass produced high-quality imprint images of pillar patterns with a 230-nm diameter. Ecofriendly antiglare film with liquid glucose and trehalose derivatives derived from biomass was indicated to achieve the real refraction index of 1.45 to 1.53 at 350 to 800 nm, low imaginary refractive index of <0.005 and low volumetric shrinkage of 4.8% during ultraviolet irradiation. A distinctive bulky glucose structure in glucose and trehalose derivatives was considered to be effective for minimizing the volumetric shrinkage of resist film during ultraviolet irradiation, in addition to suitable optical properties for high-definition display.

EUV lithography using water-developable resist material derived from biomass

A water-developable resist material which had specific desired properties such as high sensitivity of 5.0 μC/cm2, thermal stability of 160 °C, suitable calculated linear absorption coefficients of 13.5 nm, and acceptable CF4 etch selectivity was proposed using EB lithography for EUV lithography. A water developable resist material derived from biomass is expected for non-petroleum resources, environmental affair, safety, easiness of handling, and health of the working people, instead of the common developable process of trimethylphenylammonium hydroxide. 100 nm line and 400 nm space patterning images with exposure dose of 5.0 μC/cm2 were provided by specific process conditions of EB lithography. The developed trehalose derivatives with hydroxyl groups and EB sensitive groups in the water-developable resist material derived from biomass were applicable to future development of high-sensitive and resolution negative type of water-developable resist material as a novel chemical design.

Study of Dill's B parameter measurement of EUV resist

Our group previously explored methods for measuring simulation parameter for advanced chemically amplified (CA) resists, including development parameters [1]. Dill’s C parameter [2-3] , acid diffusion length generated from PAG [4], and de-protection reaction parameters [5-6]. We performed simulations of EUV resists using these parameters, the results of which allowed us to examine the conditions for reducing LER and improving resolution. This paper discusses a method for measuring the Dill’s B parameter, which had been difficult to measure with conventional methods. We also confirmed that enhancing the resist polymer’s EUV light absorption is effective in improving the sensitivity of the CA resist.

Development of plant-based resist materials in electron beam lithography

Electron beam lithography has great potential for future production of nano-imprint templates, light-emitting diodes, solar cell devices, actuators, biosensors, and micro electro mechanical systems (MEMS) where continued success ultimately requires improvements in current processing technologies. Electron beam lithography is promising for advancing multiple electronic applications due to several advantages such as high resolution, deep depth of focus, flexibility in material design, and assumable cost. This study presents progress in the development of a new plant-based resist material (TPU-EBR1) to achieve high exposure sensitivity and lower film thickness shrinkage by electron beam irradiation. Highly efficient crosslinking properties and high quality patterning line images were provided by specific process conditions of 30 keV electron beam lithography. Lower film thickness shrinkage of the newly developed TPU-EBR than that of the referenced acrylate type resist material is one of key to achieve EB patterning. The validity of our approach using the developed TPU-EBR was confirmed experimentally. In addition, this new approach was demonstrated to apply glucose and dextrin derivatives as the eco-friendlier compounds to the resist materials in micro and nano-patterning processes for environmentally-compatible electronic device fabrications.

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.

Fabrication of optical film derived from biomass using eco-friendly nanoimprint lithography

This paper presents the chemical design and fabrication of optical film derived from biomass using eco-friendly nanoimprint lithography. The optical film derived from biomass with subwavelength structures was successfully demonstrated in specific desired properties. The linearly polymerized polysaccharide in optical film derived from biomass indicated two effects of high concentration of acrylate group in the side-chain terminus for highly sensitivity, and the ring components containing bulky disaccharide for suitable optical properties. The optical film derived from biomass is applicable to future development of antireflective material with subwavelength structures and suitable refractive index material as a chemical design concept.

Development of water-developable resist material derived from biomass in EB lithography

A water developable, non-chemically amplified, high sensitive, and negative tone resist material in the developable process of EB lithography was investigated for environmental affair, safety, easiness of handling, and health of the working people, instead of the common developable process of trimethylphenylammonium hydroxide or resist solvents. The material design concept to use the plantbased resist material derived from biomass was proposed. A novel high-sensitive negative tone of plantbased resist material with the sugar chain structure derived from biomass on underlayer was demonstrated in EB lithography for the future production of optical and electronic devices. The 400 nm line patterning images with exposure dose of 7.0 μC/cm2 were provided by specific process conditions of EB lithography for optical and electronic devices.