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Itani T.,EUVL Infrastructure Development Center Inc. | Kozawa T.,Osaka University
Japanese Journal of Applied Physics | Year: 2013

Extreme ultraviolet (EUV) radiation, the wavelength of which is 13.5 nm, is the most promising exposure source for next-generation semiconductor lithography. The development of EUV lithography has been pursued on a worldwide scale. Over the past decade, the development of EUV lithography has significantly progressed and approached its realization. In this paper, the resist materials and processes among the key technologies of EUV lithography are reviewed. Owing to its intensive development, the resist technology has already closely approached the requirements for the 22 nm node. The focus of the development has shifted to the 16nm node and beyond. Despite the trade-off relationships among resolution, line edge roughness/line width roughness, and sensitivity, the capability of resist technology will go beyond the 16nm node. © 2013 The Japan Society of Applied Physics.


Kozawa T.,Osaka University | Santillan J.J.,EUVL Infrastructure Development Center Inc. | Itani T.,EUVL Infrastructure Development Center Inc.
Japanese Journal of Applied Physics | Year: 2013

With the approach of the realization of extreme ultraviolet (EUV) lithography, practical issues such as the defects of resist patterns have attracted attention. In this study, the defects of line-and-space resist patterns were investigated from the viewpoint of the stochastic effects of chemical reactions. The stochastic effect was expressed using the standard deviation of the protected-unit concentration. To eliminate bridges within a 6.8 m length in the line direction, a 1.5-2.0 difference is required between the average protected-unit concentration and the dissolution point at the center of the space. To eliminate line breaks and severe pinching within a 6.1 μm length in the line direction, a 1.2-1:6 difference is required between the average protected-unit concentration and the dissolution point at the center of the resist line pattern. © 2013 The Japan Society of Applied Physics.


Kozawa T.,Osaka University | Santillan J.J.,EUVL Infrastructure Development Center Inc. | Itani T.,EUVL Infrastructure Development Center Inc.
Applied Physics Express | Year: 2013

Extreme ultraviolet (EUV) lithography is promising for the high-volume production of semiconductor devices for the 16 nm node and below. However, the stochastic effect is a significant concern in lithography using high-energy (92.5 eV) photons and highly sensitive resists. In this study, we report a technique for evaluating the stochastic effect on line edge roughness (LER). Resist patterns were analyzed using a Monte Carlo simulation on the basis of the sensitization and reaction mechanisms of chemically amplified EUV resists. The contribution of protected unit fluctuation to LER was estimated to be ±0.31 to ±0.37σ. Copyright © 2013 The Japan Society of Applied Physics.


Kozawa T.,Osaka University | Santillan J.J.,EUVL Infrastructure Development Center Inc. | Itani T.,EUVL Infrastructure Development Center Inc.
Applied Physics Express | Year: 2012

Chemically amplified resists with an acid generator, the anion of which is bound to the polymer through a covalent bond (anion-bound resists), are promising materials for the 16nm node and beyond. However, their reaction mechanism is unknown. In this study, we propose a proton diffusion model for anion-bound resists. To examine the proton diffusion model, we carried out resist-patterning experiments and a simulation. The calculated latent images corresponded well to the measured line width and estimated chemical gradient. This result suggests that protons diffuse under the electric field produced by anions and induce acid-catalytic reactions in anion-bound resists. © 2012 The Japan Society of Applied Physics.


Santillan J.J.,EUVL Infrastructure Development Center Inc. | Itani T.,EUVL Infrastructure Development Center Inc.
Journal of Photopolymer Science and Technology | Year: 2013

The dissolution characteristics of EUV resist patterns as they are formed during the development process were analyzed using the HS-AFM. This in situ dissolution analysis method has been significantly optimized and can now be utilized for the analysis of 32 nm hp L/S pattern developed with a standard concentration (0.26 N) of the tetramethyl ammonium hydroxide developer solution. Further investigations have shown that this method is presently limited to hp L/S patterns around 32 nm hp L/S. This was mainly attributed to the comparatively thick radius of curvature of presently available cantilevers. Furthermore, the results obtained here have shown that resists of good pattern LWR exhibit smooth patterns even during dissolution. On the other hand, resists of comparatively large LWR also show signs of such roughness even during the dissolution process. These results show the possibility of defining the formation mechanism of LWR during the development process. © 2013SPST.

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