Hiroyuki Kagami

Development of nano-surgery system for cell organelles

A nano-surgery system has been developed for operation of minute organelles in a cell. such as chloroplast and mitochondria. For the operation, nano-pipettes, nano-manipulators, sample stage, and bellows pump were fabricated. It has been succeeded to prick a chromosphere in a plant cell and the membrane just under the nucleus of an animal cell with the tip of nano-pipette and to inject fluorescent dye into these organelles.

An Extended Dynamic Model of a Geyser Induced by an Inflow of Gas (2)

We modified further our extended dynamic model of a geyser induced by an inflow of gas, by taking into consideration the effects during spouting of an elbow shape, pairs of sudden expansions and contractions, and repeats of this shape in an underground watercourse. Through numerical simulations of this extended dynamic model, we see that a large number of sudden expansions and contractions or a large angular elbow in the underground watercourse greatly affects the spouting dynamics of the geyser.

Thickness control of a thin film after drying through thermal and evaporative management in drying process of a polymer solution coated on a flat substrate: application of the dynamical model of the drying process

We have proposed and modified a model of drying process of polymer solution coated on a flat substrate for flat polymer film fabrication supposing resist coating process in semiconductor engineering process and so on. And we have clarified dependence of distribution of polymer molecules on a flat substrate on a various parameters based on analysis of many numerical simulations of the model. Then we applied the model to thickness control of a thin film after drying through thermal management. But minute thickness control of a thin film after drying was not enough and more minute thickness control of it was desired. Therefore, in this study, we add evaporative management for more minute thickness control of a thin film after drying. As a result, thickness control of a thin film after drying in drying process of a polymer solution coated on a flat substrate can be improved further through adding evaporative operations to thermal operations artificially and instantaneously depending on solutes distribution during drying.

Applying the dynamical model of drying process of a polymer solution coated on a flat substrate to effects of bumpy substrate

We apply the former general dynamical model of drying process of polymer solution coated on a flat substrate for flat polymer film fabrication to concrete detailed subjects. Concretely we apply the model to effects of a bumpy substrate as an example. We understand that a humpy structure on a substrate does not affect nearly solutes distribution after drying because effects of diffusion around the hump are sufficiently effective as far as the hump interfere with diffusion. We also understand that when the beginning time of special vaporization near a hump is earlier, solutes distribution after drying except for at the edges region is thinner a little because leveling including the edges region by diffusion is more effective.

Characteristic three-dimensional structure of resist's distribution after drying a resist solution coated on a flat substrate: analysis using the extended dynamical model of the drying process

We extend the former dynamical model of drying process of a resist solution coated on a flat substrate to three-dimensional one. And through numerical simulation of the extended dynamical model we clarified characteristic three-dimensional structure of resists thickness distribution after drying. And we confirmed characteristic thickness distribution of resist thin film obtained by two-dimensional model through three-dimensional model again.

A modified dynamical model of drying process of polymer blend solution coated on a flat substrate

We have proposed and modified a model of drying process of polymer solution coated on a flat substrate for flat polymer film fabrication. And for example numerical simulation of the model reproduces a typical thickness profile of the polymer film formed after drying. Then we have clarified dependence of distribution of polymer molecules on a flat substrate on a various parameters based on analysis of numerical simulations. Then we drove nonlinear equations of drying process from the dynamical model and the fruits were reported. The subject of above studies was limited to solution having one kind of solute though the model could essentially deal with solution having some kinds of solutes. But nowadays discussion of drying process of a solution having some kinds of solutes is needed because drying process of solution having some kinds of solutes appears in many industrial scenes. Polymer blend solution is one instance. And typical resist consists of a few kinds of polymers. Then we introduced a dynamical model of drying process of polymer blend solution coated on a flat substrate and results of numerical simulations of the dynamical model. But above model was the simplest one. In this study, we modify above dynamical model of drying process of polymer blend solution adding effects that some parameters change with time as functions of some variables to it. Then we consider essence of drying process of polymer blend solution through comparison between results of numerical simulations of the modified model and those of the former model.

Nonlinear dynamics that appears in the dynamical model of drying process of a polymer solution coated on a flat substrate

We have proposed and modified the dynamical model of drying process of polymer solution coated on a flat substrate for flat polymer film fabrication and have presented the fruits through some meetings and so on. Though basic equations of the dynamical model have characteristic nonlinearity, character of the nonlinearity has not been studied enough yet. In this paper, at first, we derive nonlinear equations from the dynamical model of drying process of polymer solution. Then we introduce results of numerical simulations of the nonlinear equations and consider roles of various parameters. Some of them are indirectly concerned in strength of non-equilibriumity. Through this study, we approach essential qualities of nonlinearity in non-equilibrium process of drying process.

Impact of the Marangoni effect on the polymer thin film thickness profile after drying polymer solution coated on a flat substrate

Drying process of polymer solution coated on a flat substrate is very important in various industrial applications. Then we have proposed and modified a model of drying process of polymer solution coated on a flat substrate for flat polymer film fabrication. In the previous study, we added Marangoni effect as pseudo-negative diffusion on an upper gas-liquid interface to the former model. And we saw through numerical simulation of the modified model that solute on upper gas-liquid interface was attracted more strongly to the edge due to Marangoni effect. In this study, we show that this effect is remarkable on upper gas-liquid interface, while the effect extends to sufficiently inside of the polymer solution film.

Verification of the modified model of drying process of a polymer liquid film on a flat substrate by experiment

No abstract available.

The influence of spatio-temporal variation of temperature distribution in a polymer solution on a flat substrate on formation of polymer film's thickness distribution during the drying process, based on results of simulation of the modified model

We did many numerical simulation of the modified model of drying process for the flat polymer (resist) film fabrication taking effects of latent heat and heat conductivity into account and studied effects of introducing latent heat and heat conductivity to the model. From those we clarified dependence of distribution of resist molecules on a substrate on latent heat of solvent. Moreover, we clarified why above characteristic dependence of distribution of resist molecules on latent heat appeared.