Mold Design and Fabrication for Surface Relief Gratings by Glass Nanoimprint

Mori, Toshiharu; Kimoto, Yoshihisa; Kasa, Haruya; Kintaka, Kenji; Hotou, Norihito; Nishii, Junji; Hirai, Yoshihiko

doi:10.1143/jjap.48.06fh20

Cited by 14 publications

(11 citation statements)

References 21 publications

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“…Figure 4 depicts the X-ray diffraction pattern of the watersoaked glass after heating under vacuum. Peaks due to bismuth metal were observed as well as additional peaks assigned to Bi 2 O 2 CO 3 or Bi(OH) 3 .…”

Section: ¹3mentioning

confidence: 99%

Browning of bismuth borate glass by heat treatment under vacuum

Fukumi

Kitamura

Nishii

2012

J. Ceram. Soc. Japan

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Browning after heating under vacuum has been studied on bismuth borate glasses. It was found that the reaction of water with glass surfaces was a necessary step for browning and that browning occurred at the surface of glass. The fraction of Bi atoms forming Bi metal was about 1%. It was deduced that browning was caused by the formation of Bi metal particles through the dehydration of hydrated layer of the glass surface.©2012 The Ceramic Society of Japan. All rights reserved.Key-words : Bismuth borate glasses, Heat treatment, Browning [Received July 4, 2012; Accepted September 4, 2012] Bismuth borate glasses have low deformation temperature and high refractive index. 1) Therefore, bismuth borate glasses are used as high refractive index optical glasses for mold pressing. Recently, a glass nano-imprinting method, which is one kind of mold pressing methods, has been developed for the fabrication of optical elements which have periodic structures with sub-micron periods on glass surfaces.2)4) In this process, glass plates or glass gobs are pressed around the glass deformation temperature by molds on which fine structures were incised. The operation is carried out under vacuum, in order to prevent molds from degradation and to avoid the formation of voids of atmospheric gases on glass surfaces. Surfaces of bismuth borate glasses sometimes became grayish-brown slightly by the heating under vacuum and included voids at worst.5) The browning and the void formation deteriorate the performance of optical elements, hence they should be avoided. The browning of bismuth borate glasses has been studied in the present study.5.3K 2 O29.0Bi 2 O 3 65.8B 2 O 3 (named KBB) glass was prepared by a conventional melting method. An appropriate mixture of K 2 CO 3 (Nacalai Tesque, 99.5%), Bi 2 O 3 (Wako Pure Chemical Industries, 99.9%) and B 2 O 3 (Kanto Chemicals, 95.0%) was melted in a platinum crucible at temperatures from 800 to 950°C for 2 h by an electric furnace and was stirred every 30 min. The melt was poured onto a brass plate to form a glass plate. The glass plate was annealed at glass transition temperature and was allowed to cool in a furnace. Then, the glass plate was cut into several pieces, and the surface of which was polished by SiC and Al 2 O 3 abrasives and subsequently by CeO 2 powder to form optically flat glass plates with a thickness of 2 mm. Water or mineral oil was used as a dispersion medium for polishing. The glass plates polished with water-and mineral-oil slurry were rinsed by acetone and cyclohexane, respectively. In addition, wrinkle-free glass marbles with a diameter of about 5 mm were prepared in KBB glass by dropping the melt on a pre-heated brass plate. The glass marble was soaked at 25°C for 24 h in water the amount of which was 2cc per 1 mm 2 surface area of the glass. 40Bi 2 O 3 60B 2 O 3 (named BB hereafter) was also prepared for comparison.Glass plates polished by water-abrasive slurry and oil-abrasive slurry, an un-soaked glass marble and a glass marble soaked in water were heated in an elec...

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Section: ¹3mentioning

confidence: 99%

Browning of bismuth borate glass by heat treatment under vacuum

Fukumi

Kitamura

Nishii

2012

J. Ceram. Soc. Japan

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“…First, AAO films with a nominal pore diameter have been fabricated over large areas by electrochemical oxidation, and their pore diameter can be tuned in the range of 6–200 nm by selecting suitable oxidation voltage and acidic electrolyte. − In particular, AAO films with a pore diameter of approximately 100 nm are used as UV nanoimprint molds to fabricate optical antireflection polymer films with nanopillars. , Second, thermal chemical vapor deposition (CVD) using acetylene gas as a carbon source produces a ultrathin carbon film on AAO surfaces. For example, an incompletely crystallized carbon film with a thickness of less than 10 nm was deposited all over the outermost and side-wall surfaces of AAO films with a pore diameter of 100 nm and then used as nanoscale carbon tubes. , We anticipated that this carbon film could function as an antisticking layer for UV-cured resins, because glassy carbon molds are used for pattern transfer to fused silica surfaces by thermal nanoimprinting − and the surface free energy of nonpolar carbon films is estimated to be as small as 6.5 mJ m –2 . Third, the size distribution of the pore diameter of AAO films is within approximately 15 nm.…”

Section: Introductionmentioning

confidence: 99%

Size-Dependent Filling Behavior of UV-Curable Di(meth)acrylate Resins into Carbon-Coated Anodic Aluminum Oxide Pores of around 20 nm

Nakagawa

Nakaya

Hoshikawa

et al. 2016

ACS Appl. Mater. Interfaces

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Ultraviolet (UV) nanoimprint lithography is a promising nanofabrication technology with cost efficiency and high throughput for sub-20 nm size semiconductor, data storage, and optical devices. To test formability of organic resist mask patterns, we investigated whether the type of polymerizable di(meth)acrylate monomer affected the fabrication of cured resin nanopillars by UV nanoimprinting using molds with pores of around 20 nm. We used carbon-coated, porous, anodic aluminum oxide (AAO) films prepared by electrochemical oxidation and thermal chemical vapor deposition as molds, because the pore diameter distribution in the range of 10-40 nm was suitable for combinatorial testing to investigate whether UV-curable resins comprising each monomer were filled into the mold recesses in UV nanoimprinting. Although the UV-curable resins, except for a bisphenol A-based one, detached from the molds without pull-out defects after radical photopolymerization under UV light, the number of cured resin nanopillars was independent of the viscosity of the monomer(s) in each resin. The number of resin nanopillars increased and their diameter decreased as the number of hydroxy groups in the aliphatic diacrylate monomers increased. It was concluded that the filling of the carbon-coated pores having diameters of around 20 nm with UV-curable resins was promoted by the presence of hydroxy groups in the aliphatic di(meth)acrylate monomers.

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“…Recently, the micro-press molding method has been used for the fabrication of glass microoptical devices. [10][11][12] However, the mold for the micro-press molding of glass requires mechanical strength and chemical stability at high temperatures. Generally, glassy carbon (GC) 13) and silicon carbide (SiC) 14) are used as mold materials.…”

Section: Introductionmentioning

confidence: 99%

Property Variation of Ni–W Electroformed Mold for Micro-Press Molding

Yasui

Kaneko

Takahashi

et al. 2013

Jpn. J. Appl. Phys.

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We proposed a simple method to fabricate a Ni–W electroformed mold for glass micro-press molding. For example, borosilicate glass (D263) was molded using the Ni–W electroformed mold. A Ni–W electroformed mold with a fine line was fabricated by photolithography and electroforming technology. Additionally, the Ni–W electroformed mold did not require a release layer. As the result of molding D263 at 883 K, the minimum pitch of the glass pattern was the same as that of the Ni–W electroformed mold. We argue that the crystallization of amorphous Ni–W occurred with the activation energy derived from the heating of micro-press molding. The heating temperature was 833 K. Additionally, the release characteristics of a Ni–W film were improved by increasing the percentage of W. In terms of the thermochemical stability and high content rate of W, we indicated that Ni–W electroformed molds can be used repeatedly for glass micro-press molding.

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Mold Design and Fabrication for Surface Relief Gratings by Glass Nanoimprint

Cited by 14 publications

References 21 publications

Browning of bismuth borate glass by heat treatment under vacuum

Browning of bismuth borate glass by heat treatment under vacuum

Size-Dependent Filling Behavior of UV-Curable Di(meth)acrylate Resins into Carbon-Coated Anodic Aluminum Oxide Pores of around 20 nm

Property Variation of Ni–W Electroformed Mold for Micro-Press Molding

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