Toho Gakuen

The development of chemically amplified resists requires many experiments to optimize the chemical composition, which includes the type of monomer molecules and their component ratios, initiator concentration, and process conditions. In addition, the optimization process requires extensive knowledge and experience. In this paper, we apply deep learning to predict the exposure properties, such as sensitivity and contrast, of KrF chemically amplified resists and to optimize the ratio of monomer components. The experimental data are used to predict photoresist development properties by deep learning using in-house code. To achieve this goal, we synthesized several photoresist resins with different proportions. Each resin was then used to prepare photoresist formulations, which were subsequently subjected to exposure and development testing under various energy conditions. Using the film thickness data obtained, we trained our deep learning system to more comprehensively predict the exposure and development curves of photoresists under different resin component conditions. The results of validation experiments showed that the predicted results were consistent with the experimental results, and the predictions for the exposure and development characteristics of different monomer component ratios were quite accurate, confirming that the deep learning outcomes possess high credibility and feasibility.

EUV lithography technology has started to be used for the fabrication of 7 nm logic devices, and has been used for mass production technology since 2020. As EUV lithography plays a more important role in semiconductor manufacturing, photoresists for EUV exposure also become more important. However, there are few places in Japan where we can use EUV exposure tool. To solve this problem, it is effective to evaluate photoresists by other wavelengths such as 248 nm to screen samples in the initial stage. In our former report, we have evaluated the correlation between KrF, EB and EUV exposure, and we showed that there are good correlations among them. In this report, we synthesized acrylic polymers by changing the ratio of protection group or molecular weight. Acrylic monomers using this report are commercially available, for example a protection group type and a lactone polarity type. Using these samples, the evaluations by KrF, ArF and EUV exposure were performed, respectively.

Abstract When shopping online, it is difficult to estimate size from visual cues in the form of product images. While package shape and color have been discussed as factors influencing perceptions of product size, this research focuses on the influence of visual cues, such as the number of dimensions of the product image (i.e., two‐dimensional image vs. three‐dimensional image) on perceptions of product size. This study involved three surveys whose results revealed that three‐dimensional product images are perceived as larger products than two‐dimensional product images. Moreover, three‐dimensional product images positively influenced perceived product weight, suggesting a downstream effect from perceived weight on willingness to pay (WTP, Study 3). The results of this study contribute to a better understanding of how consumers perceive product size from product images in online retailing. Specifically, the results of this study extend our understanding of the mechanisms behind product size perception by including the influential factor of product image dimensionality in size perception bias. In addition, these findings have practical implications. In recent years, food packaging has become smaller, but consumers may react negatively to smaller packages, even when the volume of the contents remains unchanged. For these practical concerns, it may be possible to mitigate the negative effects of downsizing by presenting product images in a three‐dimensional format.

It has been reported that the good correlation in sensitivity and resolution between EUV exposure and EB exposure because of the similar mechanism of the photochemical-reaction in photoresists during exposure. However, in the early stages of EUV resist development, there are problems on the points of the cost and time-consuming to evaluate all EUV resist materials by EB exposure. Therefore, we investigated the possibility of using KrF exposure as the initial screening of EUV resists. If the correlation between KrF exposure, EB exposure and EUV exposure can be found, it will be possible to evaluate photoresists in a step-by-step manner, such as screening with KrF exposure first, followed by EB exposure, and finally EUV exposure in the initial evaluation stage. In this paper, we report on our investigations in the case of novolac resists, PHS chemically amplified resists, acrylic chemically amplified resists, and EUV polymer resists.

Laparoscopes are now widely used in clinical settings. Laparoscopes are particularly useful in detecting cancers and excising affected areas. During laparoscopic operations, however, the spatter of blood and bodily fluids resulting from the excision of the affected area can fog the objective lens. Condensation on the lens caused by temperature differences between the instrument interior and exterior can also obscure vision. Any obstruction of the field of view during the surgical procedure must be addressed by cleaning the lens at the tip; however, doing so prolongs the time required for the procedure, makes it more invasive, and increases patient burdens. Drawing on biomimicry principles, we developed a laparoscope lens with super water-repellent and antifouling properties. This paper reports our results.

Abstract We have studied optical properties of interstellar dust around the Orion A molecular cloud to investigate the size distribution and the composition of dust grains. Orion A is one of the most studied molecular clouds in the solar vicinity (d ≃ 400 pc). In this paper, we used optical and near-infrared photometric data. The optical data were obtained by BVRI bands imaging observations. The near-infrared data consisting of JHK S bands were taken from 2MASS point source catalog. We produced some color excess maps around Orion A and measured their ratios such as E(R − I)/E(B − V). In order to investigate dust properties, we compared the observed ratios with results of simulation performed by Naoi et al. who calculated the extinction in the optical to near-infrared wavelengths based on a standard dust model. They assumed a power-law grain-size distribution with an upper cutoff radius and assumed graphite and silicate as dominant components. As a result, we found that the upper cutoff radius around Orion A is ≃0.3 μm, and silicate predominates compared with graphite (with the fraction of silicate grater than 93%). In addition, we further derived the total-to-selective extinction ratio R V from the observed extinction of A V and the color excess E(B − V), and compared it with the model calculations. Dust properties (i.e., the upper cutoff radius and the ratio of graphite/silicate) derived from R V are almost consistent with those derived from the color excess ratios.

Wetting in Cassie-Baxter state on multi-pillar and multi-hole surfaces is discussed in terms of Gibbs free energy. To discuss thermodynamic stability, free-energy differences before and after the wetting are formulated. However, no difference between the Cassie-Baxter states on multi-pillar and multi-hole surfaces is found. Furthermore, Laplace pressure generated by pillars or by a hole is discussed to find the conditions to prevent the penetration of water into the space between the pillars and the hole. As a result, it is predicted the condition in which multi-hole surface easily generates higher Laplace pressure than multi-pillar surface and easy to prevent the penetration. In other words, it is found that the multi-hole surface is a promising way to generate the Cassie-Baxter state.

In this study, we prepared the EUV metal resist, which included ZrO₂ nano-particle and three type of ligands such as 2-propenoic acid 2-methyl (MAA), propanoic acid 2-methyl (IBA) and vinylbenzoic acid (VBA). In this study, we prepared the following resists by blending each material separately for evaluating the outgassing from the view point of EUV resist materials. We prepared three type of samples on a basis of ZrO₂-MAA, ZrO₂-IBA and ZrO₂-VBA, each resist was coated on a silicon wafer, and we evaluated the outgassing from these samples during irradiation of 2 keV electron by in-situ mass spectrometry. From the results of mass spectrum, we observed the outgassing of PAG as unique peaks. And each ligand peak was distributed over the low mass range. On the other hand, the ZrO₂ peaks could not be observe in mass spectrum of each sample. Thus, ZrO₂ nano-particles might not be evaporating during 2keV electron irradiation.

To improve EUV resist sensitivity, studies have sought to enhance EUV light absorption by adding metals characterized by high EUV light absorption to the resist polymer. This approach is intended to increase secondary electron emission, thereby enhancing PAG reactivity and improving acid generation efficiency [1-3]. As reported in our previous report, to determine whether adding metals characterized by high EUV light absorption actually enhances sensitivity, we performed transmittance measurements and sensitivity evaluations of resist samples doped with ZrO2 or TeO2 nanoparticles, which have low and high EUV light absorption, respectively, in molar quantities of 0-2 relative to PAG. The samples were subjected to EUV exposure at the NewSUBARU synchrotron radiation facility. The results of transmittance measurements and sensitivity evaluations showed that, while the ZrO2-doped resist showed no changes in absorption or sensitivity, the TeO2-doped resist showed enhancement in both properties. Based on these results, we confirmed that adding metals characterized by high EUV light absorption to the EUV resist enhances its EUV light absorption and increases secondary electron emission, thereby enhancing PAG reactivity and improving acid generation efficiency [4-5]. In the efforts discussed in the present report, we examined whether adding metals directly to PAG could further enhance sensitivity by increasing the EUV light absorption of PAG itself, thereby efficiently heightening the effect of the secondary electron emission on PAG.