EUVL Infrastructure Development Center Inc.

Japan

EUVL Infrastructure Development Center Inc.

Japan

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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.


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.


Murachi T.,EUVL Infrastructure Development Center Inc. | Amano T.,EUVL Infrastructure Development Center Inc.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

In order to mitigate phase defects on EUVL mask blanks, Fiducial Marks (FMs) should be located with high registration accuracy by the EUV Actinic Blank Inspection tool, the E-Beam (EB) writer, and other inspection tools. The proposed registration accuracy is less than 10 nm for each tools [1]. In our previous studies [2] and [3] we fabricated FMs by FIB etching, or resist exposure by the EB writer and etching process, and inspected those FMs by the EUV Actinic full-field mask Blank Inspection (ABI) prototype developed at MIRAI-Selete. The registration accuracy of those FMs with the MIRAI EUV ABI prototype were not enough due to a pixel size of 500 nm on the mask in order to achieve total less than 10 nm defect location accuracy on the EUVL mask blank. We studied the registration accuracy improvement of FM on the blank by the experiment with the MIRAI EUV ABI prototype to establish the phase defect mitigation method. In this experiment, we took some images of FMs by moving the mask stage of the MIRAI EUV ABI prototype by lengths of sub-pixels. And we analyzed registration accuracy of FM by stringing those images shifting sub-pixel. This method can achieve less than 2.5 nm FM registration accuracy by the conditions equal to or more than 4 times quasimagnification, trench detection, and 50% threshold level In this presentation, we will explain the experiment results of FM registration accuracy improvement on the EUVL mask with MIRAI EUV ABI prototype to establish the phase defect mitigation method. © 2013 SPIE.


Amano T.,EUVL Infrastructure Development Center Inc. | Terasawa T.,EUVL Infrastructure Development Center Inc.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

Our recent study reveals that the propagation of a phase defect (PD) from an EUV mask substrate surface through a multilayer does not always propagate in a vertical direction. In this study, to fully understand the propagation model of PDs, two types of defects on a Qz substrate are prepared. One is space patterns fabricated by a mask patterning process followed by an etching giving a cross-sectional angle of 90 degrees. The others are AFM scratched space patterns with their cross-sectional angles as 30 and 60 degrees. After coating, a patterned Qz substrate with a multilayer, propagation of PDs through the multilayer was observed by a TEM. As a result, the TEM images clearly exhibited a tendency that originating from the Qz substrate while the PDs propagated through the multilayer their propagation path was inclined toward the center of the mask. A maximum inclination of this path was found to be 5.9 degrees at a distance of 93 mm away from the mask's center. The impacts of the inclination angles on the printed images on wafer calculated using a simulator. A phase defect with an inclination angle of one degree corresponded to a positional shift of one nanometer on printed wafer image. © 2013 SPIE.


Santillan J.J.,EUVL Infrastructure Development Center Inc. | Itani T.,EUVL Infrastructure Development Center Inc.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

Preliminary results of in situ analyses of dissolution of resist patterns of half-pitch (hp) lines and spaces (L/S) using high-speed atomic force microscopy are discussed. Initial experiments were conducted on an EUV-exposed 32 nm hp L/S pattern using a standard concentration (0.26 N) of tetramethylammonium hydroxide (TMAH) developer solution. This was done using a carbon nanofiber-based cantilever tip and after various tool enhancements and optimizations. Difference in the dissolution characteristics of various resist polymers such as polyhydroxystyrene (PHS)-based and hybrid (PHS-methacryl) resists was observed. These results are in agreement with the previously obtained results of measurements performed with 32 nm isolated line patterns on resist films developed with diluted developer solutions (1/20 of 0.26 N TMAH), where the PHS-based resist showed a uniformly dissolved, grain-like dissolution characteristic, while the hybrid resist exhibited resist swelling of the exposed resist film. © 2013 SPIE.


Yamane T.,EUVL Infrastructure Development Center Inc. | Terasawa T.,EUVL Infrastructure Development Center Inc.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

We have developed actinic inspection systems to detect multilayer phase-defects with dark field imaging. Although a prototype system for full-field inspection is available for half-pitch (hp) 16 nm node from the viewpoint of inspection sensitivity, but the inspection time for such a full-field area of a mask requires 4.8 hours and hence the technique is not viable for a high-volume manufacturing (HVM) application. To reduce the inspection time of the prototype, its signal to noise ratio was analyzed. The result shows that an "n" times faster scanning speed would require an "n" times enhancement of the illumination intensity for the system. The intensity was enhanced by 1.7 times, by improving the optic efficiency of the system where full-field inspection time reduced from 4.8 hours to 3.25 hours, and where the detection probability was also improved. These results are applied towards the development of a HVM prototype, and for evaluating 11 nm node inspection techniques. © 2012 SPIE.


Santillan J.J.,EUVL Infrastructure Development Center Inc. | Itani T.,EUVL Infrastructure Development Center Inc.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

In this paper, the'pattern formation'characteristics of a polyhydroxystyrene (PHS)-acryl hybrid extreme ultraviolet (EUV) resist was investigated using a high speed atomic force microscope. This analysis covers the dissolution or development, rinse and drying processes that are conventionally applied after EUV exposure and post exposure bake. As a result, it was found that during the development process, the EUV-exposed resist film exhibited swelling characteristics. This was assumed to be the effect of the balance / imbalance in dissolvability introduced by the hydrophobic acryl and hydrophilic PHS components of this hybrid resist. During the rinse process with de-ionized water, the critical dimension (CD) of the resulting line pattern after development was observed to increase with rinse time. This was attributed to a possible permeation of water into the resist line pattern causing the CD to swell. Lastly, for the drying process, the same line pattern CD was found to shrink similar to pre-rinse sizes and taper at the top edges. This suggests evaporation of the rinse water imbedded into the resist line pattern. © 2012 SPIE.


Toriumi M.,EUVL Infrastructure Development Center Inc. | Itani T.,EUVL Infrastructure Development Center Inc.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

EUV resist materials are requested simultaneously to improve the resolution, line-edge roughness (LER), and sensitivity (RLS). In a resist film inhomogeneous structures in nanometer region may have large effects on directly the resolution and LER and indirectly on sensitivity. Inhomogeneity of PAGs in a hybrid resist for EUV lithography was investigated using molecular dynamics simulations. The hybrid resist film showed the inhomogeneous positions and motions of PAG cations and anions. Free volumes in resist matrix influence the motions of PAGs. Molecular structure such as bulky phenyl groups of a PAG cation localize the positions and reduce the motion of a cation. Chemical properties such as ionic interactions and lone-pair interaction also play an important role to determine the inhomogeneity of PAGs. Fluorine interaction enables active motions of PAG anions. © 2014 SPIE.

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