JP2006049293A - Field-emission electron gun and electron beam application apparatus using the same - Google Patents
Field-emission electron gun and electron beam application apparatus using the same Download PDFInfo
- Publication number
- JP2006049293A JP2006049293A JP2005189138A JP2005189138A JP2006049293A JP 2006049293 A JP2006049293 A JP 2006049293A JP 2005189138 A JP2005189138 A JP 2005189138A JP 2005189138 A JP2005189138 A JP 2005189138A JP 2006049293 A JP2006049293 A JP 2006049293A
- Authority
- JP
- Japan
- Prior art keywords
- field emission
- fibrous carbon
- carbon material
- electron gun
- electrons
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Abstract
Description
本発明は、電界放出型電子銃およびそれを搭載した電子ビーム応用装置に関する。 The present invention relates to a field emission electron gun and an electron beam application apparatus equipped with the same.
繊維状炭素物質はその先端径がナノレベルと非常に小さいため、角電流密度が高く、仮想光源サイズが小さいため、これを電子顕微鏡の電子源に適用した場合、高輝度な電子ビームが得られることが知られている（Niels de Jonge, J. Appl. Phys. 95, 673 (2004）、（非特許文献１））。しかし、電子顕微鏡の高分解能化のためには、電子源からの放出電子のエネルギー幅が狭いことが必要であるが、繊維状炭素物質では従来のタングステン電子源と同等であるため、高分解能化は期待できないという課題がある。 Since the fibrous carbon material has a very small tip diameter of nanometer level, the angular current density is high and the virtual light source size is small. Therefore, when this is applied to the electron source of an electron microscope, a high-intensity electron beam is obtained. (Niels de Jonge, J. Appl. Phys. 95, 673 (2004), (Non-patent Document 1)). However, in order to increase the resolution of the electron microscope, it is necessary that the energy width of the emitted electrons from the electron source is narrow. However, since the fibrous carbon material is equivalent to the conventional tungsten electron source, the resolution is increased. There is a problem that cannot be expected.
また、Ｘ線分光分析等に使用される微小Ｘ線源用の電子源として、炭素と共に、ホウ素及び窒素からなる群から選択された少なくとも一種を含有する面電子源を使用することにより、電子放出効率が向上するということが、特開２００３−３６８０５号公報（特許文献１）に開示されている。 Electron emission by using a planar electron source containing at least one selected from the group consisting of boron and nitrogen together with carbon as an electron source for a micro X-ray source used for X-ray spectroscopic analysis and the like. It is disclosed in Japanese Patent Laid-Open No. 2003-36805 (Patent Document 1) that the efficiency is improved.
しかし、炭素にホウ素あるいは窒素をドーピングすることにより放出電子のエネルギー幅が狭くなるという記載はない。また、面電子源のみについて記載されており、電子顕微鏡用の電子源についての記載はない。 However, there is no description that the energy width of emitted electrons is narrowed by doping boron or nitrogen into carbon. Further, only the surface electron source is described, and there is no description about the electron source for the electron microscope.
高輝度かつ高分解能な顕微鏡像が得られる電子顕微鏡や高精細描画可能な電子線描画装置を実現するためには、高輝度かつ狭エネルギー幅の電子ビームが得られる電子銃を搭載することが必要不可欠である。 In order to realize an electron microscope capable of obtaining a high-brightness and high-resolution microscope image and an electron beam drawing apparatus capable of high-definition drawing, it is necessary to mount an electron gun capable of obtaining an electron beam with high brightness and a narrow energy width. It is essential.
本発明の第一の目的は、高輝度かつ狭エネルギー幅の電子ビームが得られる電界放出型電子銃を提供することにある。 A first object of the present invention is to provide a field emission electron gun capable of obtaining an electron beam with high brightness and a narrow energy width.
本発明の第二の目的は、該電界放出型電子銃を搭載した電子ビーム応用装置を提供することにある。 A second object of the present invention is to provide an electron beam application apparatus equipped with the field emission electron gun.
本発明の第一の目的を達成するための手段は、繊維状炭素物質とそれを支持する導電性基材から構成される電界放出型陰極と、電子を電界放出させる引出装置と、電子を加速させる加速装置を有する電界放出型電子銃において、該繊維状炭素物質に原子価が３価および５価の元素のうち少なくとも１種が含有されていることにある。特に、３価および５価の元素はそれぞれホウ素および窒素が望ましい。 Means for achieving the first object of the present invention includes a field emission cathode composed of a fibrous carbon material and a conductive base material supporting the fibrous carbon material, an extraction device for field emission of electrons, and acceleration of electrons. In the field emission electron gun having the acceleration device, the fibrous carbon material contains at least one of trivalent and pentavalent elements. In particular, the trivalent and pentavalent elements are preferably boron and nitrogen, respectively.
また、該原子価が３価および５価の元素の含有量は、該繊維状炭素物質の径方向で、連続あるいは非連続に変化し、中心部よりも表層部の方が多いことにある。電子放出に影響するのは表層部の３価または５価の原子と考えられ、表層部に電子が存在すれば、電子線の半値幅を小さくするという効果が得られる。一方、全体を３価，５価の原子を混合した場合には、カーボンナノチューブの結晶性（強度）が低下するので、表層部に多く３価・５価の原子を存在させることで、半値幅を小さくするとともにナノチューブの強度（結晶性）を維持できる。 In addition, the content of the trivalent and pentavalent elements changes in the radial direction of the fibrous carbon material in a continuous or non-continuous manner, and the surface layer portion is larger than the central portion. It is considered that the trivalent or pentavalent atom in the surface layer part affects the electron emission. If electrons exist in the surface layer part, the effect of reducing the half width of the electron beam can be obtained. On the other hand, when trivalent and pentavalent atoms are mixed as a whole, the crystallinity (strength) of the carbon nanotubes decreases, so by having many trivalent and pentavalent atoms in the surface layer part, The strength (crystallinity) of the nanotube can be maintained.
さらに、本発明の各電子銃ごとに電子源となる各一本の繊維状炭素物質を有し、該一本の繊維状炭素物質へのホウ素および窒素のうち少なくとも１種の含有量が、炭素に対する原子重量比として０.１ 〜５％であり、該一本の繊維状炭素物質の直径は、２０〜２００ｎｍとすることが好ましい。 Further, each electron gun according to the present invention has a single fibrous carbon material serving as an electron source, and the content of at least one of boron and nitrogen in the one fibrous carbon material is carbon. The atomic weight ratio with respect to is 0.1 to 5%, and the diameter of the one fibrous carbon material is preferably 20 to 200 nm.
繊維状炭素物質の直径、特に先端径が大きいほど、エミッション電流の増大によるエネルギー幅増大効果（ベルシェ効果）は低減できる。また、先端径が太いほど、エミッション電流が大きい際の半値幅を小さくすることができる。しかし、ＣＮＴの結晶性が悪くなるので、２００ｎｍ以下とすることが好ましい。 As the diameter of the fibrous carbon material, particularly the tip diameter, is larger, the energy width increase effect (Belcher effect) due to the increase in emission current can be reduced. Further, the thicker the tip diameter, the smaller the full width at half maximum when the emission current is large. However, since the crystallinity of CNT deteriorates, the thickness is preferably 200 nm or less.
また、一本の繊維状炭素物質とそれを支持する導電性基材から構成される電界放出型陰極と、電子を電界放出させる引出装置と、電子を加速させる加速装置を有する電界放出型電子銃において、該一本の繊維状炭素物質からのエミッション電流が１０ｎＡの場合の電界放出電子のエネルギー半値幅が０.２５ｅＶ 以下、あるいはエミッション電流が１μＡの場合の電界放出電子のエネルギー半値幅が０.３５ｅＶ 以下であるものとすることを特徴とする電界放出型電子銃である。 A field emission electron gun having a field emission cathode composed of one fibrous carbon material and a conductive base material supporting the fibrous carbon material, an extraction device for electron emission of electrons, and an acceleration device for acceleration of electrons In this case, the energy half-value width of field emission electrons when the emission current from the one fibrous carbon material is 10 nA is 0.25 eV or less, or the energy half-value width of field emission electrons when the emission current is 1 μA is 0.5. A field emission electron gun characterized by having a voltage of 35 eV or less.
エミッション電流値は電子銃を適用する電子顕微鏡等の装置構成により異なる。エミッション電流が１０ｎＡの場合はＣＮＴ本来の電子状態を反映した(先端径の影響は小さい)エネルギー半値幅が期待でき、性能のよい電子銃を提供可能である。エミッション電流が１μＡ以上の場合は半値幅はＣＮＴの先端半径に依存し、先端径が小さいほど、少ないエミッション電流で急激にエネルギー半値幅が大きくなってしまうので、ドープの効果および先端の直径を調整することで、上記特性を満たす電子銃を提供可能である。 The emission current value varies depending on the configuration of an apparatus such as an electron microscope to which the electron gun is applied. When the emission current is 10 nA, an energy half width reflecting the original electronic state of the CNT (small influence of the tip diameter) can be expected, and a high-performance electron gun can be provided. When the emission current is 1μA or more, the half-value width depends on the tip radius of the CNT. The smaller the tip diameter, the larger the half-value width with less emission current, so the effect of doping and the tip diameter are adjusted. By doing so, an electron gun satisfying the above characteristics can be provided.
本発明の第二の目的を達成するための手段は、上記本発明の電界放出型電子銃を各種電子ビーム応用装置に適用することである。 Means for achieving the second object of the present invention is to apply the field emission electron gun of the present invention to various electron beam application apparatuses.
本発明により、高輝度かつ狭エネルギー幅な電子ビームを放出する電界放出型電子銃およびそれを用いた電界放出型電子顕微鏡，測長ＳＥＭ，電子線描画装置を提供することができる。 According to the present invention, it is possible to provide a field emission electron gun that emits an electron beam having a high luminance and a narrow energy width, a field emission electron microscope, a length measuring SEM, and an electron beam drawing apparatus using the same.
本発明の実施形態について図面を参照しつつ詳細に説明する。 Embodiments of the present invention will be described in detail with reference to the drawings.
本実施例に係る電子銃構成を図１に示す。本実施例に係る電子銃は３価および５価の元素であるホウ素および窒素のうち少なくとも１種が含有されている一本の繊維状炭素物質とそれを支持する導電性基材から構成される電界放出型陰極と、電子を電界放出させる引出装置と、電子を加速させる加速装置から構成される。但し、該電界放出型陰極の電界電子放出特性が最大限に発揮できる電子銃構成であれば、これに限定されるものではない。 FIG. 1 shows an electron gun configuration according to this embodiment. The electron gun according to the present embodiment is composed of one fibrous carbon substance containing at least one of trivalent and pentavalent elements boron and nitrogen, and a conductive base material supporting the fibrous carbon substance. It comprises a field emission cathode, an extraction device for electron emission of electrons, and an acceleration device for acceleration of electrons. However, the present invention is not limited to this as long as the electron gun configuration can maximize the field electron emission characteristics of the field emission cathode.
例えば本実施例に示される静電型電子銃構成でなくとも、図２に示すような引出電極を球面収差の小さい磁界レンズに置き換えた磁界界浸型電子銃構成であってもよい。 For example, instead of the electrostatic electron gun configuration shown in the present embodiment, a magnetic field immersion electron gun configuration in which the extraction electrode as shown in FIG. 2 is replaced with a magnetic lens with small spherical aberration may be used.
図３に窒素をドープした繊維状炭素物質を用いた本実施例に係る電界放出型陰極先端部のＳＥＭ写真を示す。電界放出型陰極は一本の繊維状炭素物質と導電性基材とそれを支持する絶縁性の支持台および電極から構成されている。繊維状炭素物質と導電性基材の接合部は導電性被覆層により補強されている。 FIG. 3 shows an SEM photograph of the tip of the field emission cathode according to this example using a fibrous carbon material doped with nitrogen. The field emission cathode is composed of a single fibrous carbon material, a conductive base material, an insulating support base and electrodes for supporting it. The joint between the fibrous carbon material and the conductive substrate is reinforced by a conductive coating layer.
導電性基材の材質としては、特に限定されるものではないが、融点，耐酸化性，機械的強度の点から、貴金属（具体的には、金，銀，白金族），結晶質カーボンあるいは高融点金属（具体的には、タングステン，タンタル，ニオブ，モリブデン等）が好ましい。 The material of the conductive substrate is not particularly limited, but in terms of melting point, oxidation resistance and mechanical strength, noble metal (specifically, gold, silver, platinum group), crystalline carbon or High melting point metals (specifically, tungsten, tantalum, niobium, molybdenum, etc.) are preferred.
また、導電性基材の中心軸と繊維状炭素物質とのなす角度を制御できるように、化学エッチング等で先端を鋭利化させた導電性基材先端部にＦＩＢ加工等により平坦面を形成させる。なお、繊維状炭素物質から放出される電子ビームの放射角を考慮すると、導電性基材の中心軸と繊維状炭素物質とのなす角度を±５°以下にしなければ、電子ビームの光軸調整が困難になる。 In addition, a flat surface is formed by FIB processing or the like at the tip of the conductive base material sharpened by chemical etching or the like so that the angle between the central axis of the conductive base material and the fibrous carbon material can be controlled. . In consideration of the radiation angle of the electron beam emitted from the fibrous carbon material, the optical axis adjustment of the electron beam must be performed unless the angle formed between the central axis of the conductive substrate and the fibrous carbon material is ± 5 ° or less. Becomes difficult.
また、導電性基材に繊維状炭素物質を接合する直前に、接合面に形成されている酸化膜あるいはカーボンコンタミネーション層を極力除去するのが好ましい。なぜなら、電気抵抗率の高い酸化膜やカーボンコンタミネーション層を介在させた状態で導電性基材に繊維状炭素物質を接合すると、次のような問題が生じるからである。（１）繊維状炭素物質と導電性基材との接触電気抵抗が大きくなり、電子放出が阻害される。その結果、放出電流が飽和して、大きなエミッション電流が得られなくなる。（２）エミッション電流を増加させた場合、接合部での発熱によって、繊維状炭素物質あるいは導電性基材が破壊してしまう。（３）エミッション電流を増加させた場合、接合部での発熱による繊維状炭素物質の温度上昇に伴い、繊維状炭素物質から熱電子放出も同時に生じてしまう。このため、放出電子のエネルギー幅が極端に大きくなってしまう。 Moreover, it is preferable to remove as much as possible the oxide film or carbon contamination layer formed on the bonding surface immediately before bonding the fibrous carbon material to the conductive substrate. This is because if the fibrous carbon material is bonded to the conductive base material with an oxide film having a high electrical resistivity or a carbon contamination layer interposed, the following problem occurs. (1) Contact electrical resistance between the fibrous carbon material and the conductive base material is increased, and electron emission is inhibited. As a result, the emission current is saturated and a large emission current cannot be obtained. (2) When the emission current is increased, the fibrous carbon material or the conductive base material is destroyed due to heat generation at the joint. (3) When the emission current is increased, thermionic emission from the fibrous carbon material also occurs at the same time as the temperature of the fibrous carbon material increases due to heat generation at the joint. For this reason, the energy width of the emitted electrons becomes extremely large.
なお、前記カーボンコンタミネーション層とは、導電性基材と繊維状炭素物質とを電子顕微鏡内で接合する工程において、電子顕微鏡試料室に残存している炭化水素等が電子ビームで分解形成する電気抵抗率の高いアモルファスカーボンを指す。 Note that the carbon contamination layer is an electric field in which hydrocarbons and the like remaining in the electron microscope sample chamber are decomposed and formed by an electron beam in the step of joining the conductive substrate and the fibrous carbon substance in the electron microscope. It refers to amorphous carbon with high resistivity.
なお、以下のような方法で、電気抵抗率の高い酸化膜やカーボンコンタミネーション層を除去することが可能となる。（１）導電性基材の接合部をイオンスパッタ処理する。
（２）これらの層が分解，蒸発する温度に加熱する。（３）繊維状炭素物質と導電性基材との間に電圧印加し、繊維状炭素物質から電界電子放出させることにより、繊維状炭素物質接合部表面のカーボンコンタミネーション層を除去する。
In addition, it becomes possible to remove an oxide film and a carbon contamination layer with high electrical resistivity by the following method. (1) An ion sputtering process is performed on the joint portion of the conductive substrate.
(2) Heat to a temperature at which these layers decompose and evaporate. (3) A voltage is applied between the fibrous carbon material and the conductive substrate to cause field electrons to be emitted from the fibrous carbon material, thereby removing the carbon contamination layer on the surface of the fibrous carbon material junction.
また、エミッション電流を安定化させるために、引出電圧を昇圧させて、繊維状炭素物質からのエミッション電流を増加させる場合、繊維状炭素物質と引出電極との間に作用する電界による静電気力（引力）も増加し、導電性基材から繊維状炭素物質が剥離してしまうことがある。このため、導電性基材への繊維状炭素物質の取付け部分の少なくとも一部に、導電性被覆層を形成させることで、十分な接合強度を確保する必要がある。 Also, in order to stabilize the emission current, when the extraction voltage is increased to increase the emission current from the fibrous carbon material, the electrostatic force (attraction force) caused by the electric field acting between the fibrous carbon material and the extraction electrode ) Also increases, and the fibrous carbon material may peel from the conductive substrate. For this reason, it is necessary to ensure sufficient bonding strength by forming a conductive coating layer on at least a part of the attachment portion of the fibrous carbon material to the conductive substrate.
以下に、導電性被覆層の形成方法について述べる。導電性元素を含む有機ガスを導入したチャンバー内で、接触部分の少なくとも一部に電子ビームを照射することにより、短時間で十分な厚さの導電性被覆層を形成させることができる。この方法により、導電性基材より突出している繊維状炭素物質へ導電性被覆元素を付着させることなく、繊維状炭素物質と導電性基材との接合部のみを局所的に被覆し、接合補強することができる。 Below, the formation method of an electroconductive coating layer is described. A conductive coating layer having a sufficient thickness can be formed in a short time by irradiating at least part of the contact portion with an electron beam in a chamber into which an organic gas containing a conductive element is introduced. By this method, without attaching the conductive coating element to the fibrous carbon material protruding from the conductive base material, only the joint between the fibrous carbon material and the conductive base material is locally covered to thereby strengthen the joint. can do.
前記導電性元素を含む有機ガスとしては、ＦＩＢ等で通常使用されているガリウムイオンビーム等の高エネルギー重イオンビームでしか分解しない有機ガスは使用できない。これは、高エネルギー重イオンビームが繊維状炭素物質に照射されてしまうと、繊維状炭素物質自体が一瞬で損傷を受けてしまい、破断したり、照射欠陥が生じてしまうからである。このため、有機ガスを分解させるのに用いる粒子線としては繊維状炭素物質に損傷を与えない１００ｋｅＶ以下の電子ビームが好ましく、有機ガスとしても１００ｋｅＶ以下の電子ビームで分解し、かつ１００℃以下で気化するピレンモノマー，タングステンカルボニル等が好適である。これらの有機ガスに電子ビームを照射することにより、繊維状炭素物質と導電性基材との接合部のみにカーボン層やタングステン層等の導電性材料を局所的に形成させることができる。 As the organic gas containing the conductive element, an organic gas that can be decomposed only by a high energy heavy ion beam such as a gallium ion beam usually used in FIB or the like cannot be used. This is because if the fibrous carbon material is irradiated with a high-energy heavy ion beam, the fibrous carbon material itself is damaged in a moment, resulting in breakage or irradiation defects. Therefore, the particle beam used for decomposing the organic gas is preferably an electron beam of 100 keV or less that does not damage the fibrous carbon material, and the organic gas is decomposed by an electron beam of 100 keV or less and at 100 ° C. or less. Vaporizable pyrene monomer, tungsten carbonyl and the like are preferred. By irradiating these organic gases with an electron beam, a conductive material such as a carbon layer or a tungsten layer can be locally formed only at the joint between the fibrous carbon substance and the conductive substrate.
図４に本実施例に係る窒素を含有した繊維状炭素物質のＴＥＭ写真を示す。繊維状炭素物質の形状としては、電界電子放出特性，電気抵抗，耐久性の点から、直径は２０ｎｍ〜２００ｎｍ、長さは数１００ｎｍ〜数１０μｍであることが好ましい。また、図３に示すように、窒素を含有した繊維状炭素物質は多数の節から構成されており、この節の部分に多くの窒素が含有されていた。なお、所望の電界電子放出特性が得られるならば、繊維状炭素物質の形態は中空あるいは中実であっても良く、特に限定されるものではない。また、繊維状炭素物質の先端形状は図４（ａ）に示すように、閉じていても、図４（ｂ）に示すように、開いていても良い。なお、繊維状炭素物質の先端が閉じている方がエミッション電流が安定するので、好ましい。 FIG. 4 shows a TEM photograph of a fibrous carbon material containing nitrogen according to the present example. The shape of the fibrous carbon material is preferably 20 nm to 200 nm in diameter and several 100 nm to several 10 μm in length from the viewpoint of field electron emission characteristics, electric resistance, and durability. Further, as shown in FIG. 3, the fibrous carbon material containing nitrogen is composed of a large number of nodes, and a lot of nitrogen is contained in the portions of the nodes. In addition, as long as desired field electron emission characteristics can be obtained, the form of the fibrous carbon material may be hollow or solid, and is not particularly limited. Further, the tip shape of the fibrous carbon substance may be closed as shown in FIG. 4 (a) or may be opened as shown in FIG. 4 (b). Note that it is preferable that the tip of the fibrous carbon material is closed because the emission current is stabilized.
図５はホウ素あるいは窒素等の原子価が３価あるいは５価の元素をドーピングした繊維状炭素物質における自由電子の状態密度分布と繊維状炭素物質から電界放出される電子に対するポテンシャル分布および電界放出される電子のエネルギー分布を図示したものである。３価あるいは５価の元素を繊維状炭素物質にドーピングすることにより、図示されるように、フェルミレベル（ＥF ）付近に自由電子が局在化することが計算により明らかになった。該繊維状炭素物質に内向きの強電界を加えると、外部電界と鏡像力でつくられるポテンシャルによって、図示されるようなポテンシャル障壁が形成され、障壁の厚さが
１０Åのオーダになると、量子力学的トンネル効果によって、フェルミレベル付近に局在化する自由電子が真空中に放出され、図示されるような狭エネルギー幅の電子ビームが得られることになる。
FIG. 5 shows the density distribution of free electrons in a fibrous carbon material doped with a trivalent or pentavalent element such as boron or nitrogen, and the potential distribution and field emission for electrons emitted from the fibrous carbon material. The energy distribution of electrons is illustrated. It has been calculated by calculation that free electrons are localized in the vicinity of the Fermi level (E F ) as shown in the figure by doping a trivalent or pentavalent element into a fibrous carbon material. When an inward strong electric field is applied to the fibrous carbon material, a potential barrier as shown in the figure is formed by the potential created by the external electric field and mirror image force. When the thickness of the barrier is on the order of 10 mm, quantum mechanics Due to the dynamic tunnel effect, free electrons localized near the Fermi level are emitted into the vacuum, and an electron beam with a narrow energy width as shown in the figure is obtained.
図６は繊維状炭素物質における電界放出電子のエネルギー分布に及ぼす窒素のドーピング効果を実評価した結果である。なお、この時のエミッション電流は１μＡであった。窒素のドーピングにより、放出電子のエネルギー幅の半値幅（ΔＥ）は０.４ｅＶから０.２ｅＶと半減した。 FIG. 6 shows the result of actual evaluation of the doping effect of nitrogen on the energy distribution of field emission electrons in a fibrous carbon material. The emission current at this time was 1 μA. By doping with nitrogen, the half width (ΔE) of the energy width of the emitted electrons was halved from 0.4 eV to 0.2 eV.
図７はエミッションに対するΔＥの依存性に及ぼす繊維状炭素物質への窒素のドーピングの効果を評価した結果である。繊維状炭素物質に窒素をドーピングすることにより、
ΔＥが大幅に低減した。
FIG. 7 shows the results of evaluating the effect of doping nitrogen on the fibrous carbon material on the dependence of ΔE on emissions. By doping nitrogen into the fibrous carbon material,
ΔE was greatly reduced.
上述のようにこれらのドーピングの効果は、一定範囲に放出電子帯が形成され、その結果として放出電子のエネルギー幅が小さくなる点にある。従って、上述のようにホウ素でも同様の効果が認められると予想される。 As described above, the effect of these dopings is that an emission electron band is formed in a certain range, and as a result, the energy width of the emission electrons is reduced. Therefore, as described above, it is expected that the same effect can be observed with boron.
なお、窒素含有量が、炭素に対する原子重量比として０.１ ％以上で、ΔＥが低減しはじめ、窒素含有量が増加するにつれて、ΔＥがより低減するが、５％以上になると、繊維状炭素物質を構成するグラファイト層が大きく歪みはじめ、折れ曲がったり、欠陥が多く発生し、機械的特性が劣化する。このことから、繊維状炭素物質におけるホウ素あるいは窒素に代表される原子価が３価あるいは５価のドープ元素の元素の含有量は、炭素に対する原子重量比として０.１ 〜５％が好ましい。 Note that when the nitrogen content is 0.1% or more as an atomic weight ratio with respect to carbon, ΔE begins to decrease, and as the nitrogen content increases, ΔE further decreases. The graphite layer constituting the material begins to be greatly distorted, bent, has many defects, and the mechanical properties deteriorate. For this reason, the content of the element of the dope element having a trivalent or pentavalent valence represented by boron or nitrogen in the fibrous carbon material is preferably 0.1 to 5% as an atomic weight ratio with respect to carbon.
なお、ホウ素あるいは窒素がドーピングされた繊維状炭素物質は、アーク放電法，プラズマ合成法，パルスレーザ蒸着，気相熱合成法等、周知の方法で製造することができる。また、製造された繊維状炭素物質中のドーピング元素の含有量はＸＰＳ，ＴＥＭ−EELS等で組成分析することで確認することができる。以下に、本実施例で実施した繊維状炭素物質の作製方法を下記する。 The fibrous carbon material doped with boron or nitrogen can be produced by a known method such as an arc discharge method, a plasma synthesis method, pulse laser deposition, or a vapor phase thermal synthesis method. Further, the content of the doping element in the produced fibrous carbon material can be confirmed by analyzing the composition with XPS, TEM-EELS, or the like. Below, the preparation methods of the fibrous carbon substance implemented in the present Example are described below.
（１）窒素をドーピングした繊維状炭素物質の作製法（その１）
ゾル・ゲル法により支持触媒であるＦｅ2Ｏ3／Ａｌ2Ｏ3を作製した。アルミニウムtri−sec−ブトキシ(８ｇ) をメタノール（５０ｍｌ）に溶解した後、溶液が透明になるまで希釈し、ＨＣｌ（０.０１ｍＭ）溶液を加えた。さらに、硝酸鉄Ｆｅ(ＮＯ3)3・９Ｈ2Ｏ
(３.２ｇ) を加えた後、アンモニア溶液を加え、ゲル化した。それを一晩、１００℃で乾燥させた後、６００℃で１０時間焼成し、支持触媒を作製した。その支持触媒を石英管が設置された管状の電気炉に入れ、アルゴンガス（２００sccm）を流しながら、８００℃まで昇温し、８００℃に達した時点で、水素（１００sccm）を１時間導入することにより、支持触媒の酸化物を還元した。その後、ジメチルホルムアミド ＨＯＣＮ(ＣＨ3)2をアルゴンガスをキャリアガスとして石英管に導入すると同時に、無水アンモニアガス（１００sccm）を導入することによって、窒素がドーピングされた繊維状炭素物質が合成された。
(1) Preparation method of fibrous carbon material doped with nitrogen (part 1)
Fe 2 O 3 / Al 2 O 3 as a supported catalyst was prepared by a sol-gel method. Aluminum tri-sec-butoxy (8 g) was dissolved in methanol (50 ml), diluted until the solution became clear, and HCl (0.01 mM) solution was added. Furthermore, iron nitrate Fe (NO 3 ) 3 · 9H 2 O
After adding (3.2 g), an ammonia solution was added and gelled. It was dried overnight at 100 ° C. and then calcined at 600 ° C. for 10 hours to produce a supported catalyst. The supported catalyst is put into a tubular electric furnace in which a quartz tube is installed, and heated to 800 ° C. while flowing argon gas (200 sccm). When the temperature reaches 800 ° C., hydrogen (100 sccm) is introduced for 1 hour. As a result, the oxide of the supported catalyst was reduced. Thereafter, dimethylformamide HOCN (CH 3 ) 2 was introduced into the quartz tube using argon gas as a carrier gas, and at the same time, anhydrous ammonia gas (100 sccm) was introduced to synthesize a fibrous carbon material doped with nitrogen.
（２）窒素をドーピングした繊維状炭素物質の作製法（その２）
粉末状のメラミン（ｓ−triaminotriazine）とフェロセン(dicyclopentadieny−liron)の混合粉末（メラミン：フェロセン＝４：１）を石英管が設置された管状の電気炉に挿入し、アルゴンガス（０.８ｌ／min）を流した雰囲気で１０５０℃，１５分間加熱することにより、窒素がドーピングされた繊維状炭素物質を合成した。
(2) Fabrication method of fibrous carbon material doped with nitrogen (part 2)
A mixed powder (melamine: ferrocene = 4: 1) of powdered melamine (s-triaminotriazine) and ferrocene (melamine: ferrocene = 4: 1) was inserted into a tubular electric furnace provided with a quartz tube, and argon gas (0.8 l / A fibrous carbon material doped with nitrogen was synthesized by heating at 1050 ° C. for 15 minutes in an atmosphere in which a flow of min) was performed.
（３）ボロンをドーピングした繊維状炭素物質の作製法（その１）
ボロンドーピングした繊維状炭素物質をレーザー蒸発法により作製した。ターゲットをアルゴンガス中（５００Torr）で１１００℃まで加熱した。Ｎｄ：ＹＡＧレーザー（1064ｎｍ，１０Ｈｚ）をターゲットに照射し、ターゲットを溶発させることによって、ボロンドーピングした繊維状炭素物質を作製した。ターゲットの組成は０.５ 〜１０at％Ｂ，
０.５ａｔ％Ｃｏ，０.５ａｔ％Ｎｉ、残りカーボンであった。
(3) Fabrication method of boron-doped fibrous carbon material (Part 1)
Boron-doped fibrous carbon material was prepared by laser evaporation. The target was heated to 1100 ° C. in argon gas (500 Torr). The target was irradiated with an Nd: YAG laser (1064 nm, 10 Hz), and the target was ablated, thereby producing a boron-doped fibrous carbon material. The composition of the target is 0.5-10at% B,
0.5 at% Co, 0.5 at% Ni, and remaining carbon.
（４）ボロンをドーピングした繊維状炭素物質の作製法（その２）
ボロンドーピングした繊維状炭素物質を大気中でのアーク放電法により作製した。B4C粉末を表面に塗布して黒鉛板を＋極、ＴＩＧ溶接トーチのタングステン電極を−極に接続し、アルゴンガスを流しながら電流２００Ａで１秒間放電させることによって、ボロンドーピングした繊維状炭素物質を作製した。
(4) Preparation method of fibrous carbon material doped with boron (Part 2)
Boron doped fibrous carbon material was prepared by arc discharge method in the atmosphere. Boron-doped fibrous carbon by applying B 4 C powder on the surface, connecting the graphite plate to the positive electrode and the tungsten electrode of the TIG welding torch to the negative electrode and discharging at 200 A for 1 second while flowing argon gas. The material was made.
（５）表層部に多くボロンをドーピングした繊維状炭素物質の作製法
ボロンあるいは窒素がドーピングされていない繊維状炭素物質を出発原料とし、これを酸化ホウ素（Ｂ2Ｏ3）とアンモニアガス（１×１０-6 〜１×１０4mbar）中、高温下
（１１５０℃）で反応させることにより表層部に多くボロンをドーピングした繊維状炭素物質を作製した。酸化ホウ素（Ｂ2Ｏ3）とボロンあるいは窒素がドーピングされていない繊維状炭素物質を５：１の比で混合した混合粉末をアルミナ製のるつぼに入れ、アンモニアガスを流しながら（１×１０-6〜１×１０4mbar ）、このるつぼを１１５０℃に加熱してある管状電気炉に挿入した。なお、加熱時間により、ボロンのドーピング量および濃度分布を制御した。
(5) Fabrication method of fibrous carbon material with a large amount of boron doped in the surface layer The starting material is a fibrous carbon material that is not doped with boron or nitrogen, and this is used as boron oxide (B 2 O 3 ) and ammonia gas (1 A fibrous carbon material in which a large amount of boron was doped in the surface layer portion was produced by reacting at a high temperature (1150 ° C.) in × 10 −6 to 1 × 10 4 mbar). A mixed powder in which a fibrous carbon material not doped with boron oxide (B 2 O 3 ) and boron or nitrogen is mixed at a ratio of 5: 1 is placed in an alumina crucible, and ammonia gas is allowed to flow (1 × 10 −5). 6 to 1 × 10 4 mbar), and this crucible was inserted into a tubular electric furnace heated to 1150 ° C. The boron doping amount and concentration distribution were controlled by the heating time.
上記原子価が３価および５価の元素のうち少なくとも１種が含有されている一本の繊維状炭素物質から構成される電界放出型電子銃を用いることによって、高輝度かつ狭エネルギー幅の電子ビームが得られる。 By using a field emission electron gun composed of a single fibrous carbon material containing at least one of trivalent and pentavalent elements, electrons having high brightness and narrow energy width A beam is obtained.
（電子ビーム応用装置への適用例１）
図８に本発明の電子銃を用いた走査型電子顕微鏡（ＳＥＭ）の全体構成図を示す。走査型電子顕微鏡は、電子銃から放出される電子ビームに沿って、アライメントコイル，コンデンサレンズ，非点補正コイル，偏向・走査コイル，対物レンズ，対物絞りが配置されている。試料は、試料ステージに設置され、電子ビームが照射されるようになっている。試料室内の側壁部に二次電子検出器が設けられている。また、試料室は排気系によって高真空に保持されるようになっている。このように構成されることから、電子銃から放出された電子ビームは陽極で加速され、電子レンズによって集束されて試料上の微小領域に照射される。この照射領域を二次元走査し、試料から放出される二次電子，反射電子等を二次電子検出器により検出し、その検出信号量の違いを基に拡大像を形成する。
(Application example 1 to electron beam application equipment)
FIG. 8 shows an overall configuration diagram of a scanning electron microscope (SEM) using the electron gun of the present invention. In a scanning electron microscope, an alignment coil, a condenser lens, an astigmatism correction coil, a deflection / scanning coil, an objective lens, and an objective aperture are arranged along an electron beam emitted from an electron gun. The sample is placed on a sample stage and irradiated with an electron beam. A secondary electron detector is provided on the side wall in the sample chamber. The sample chamber is maintained at a high vacuum by an exhaust system. With this configuration, the electron beam emitted from the electron gun is accelerated by the anode, focused by the electron lens, and irradiated onto a minute region on the sample. The irradiation area is scanned two-dimensionally, secondary electrons and reflected electrons emitted from the sample are detected by a secondary electron detector, and an enlarged image is formed based on the difference in the detected signal amount.
本発明の電子銃を走査型電子顕微鏡に適用することにより、従来機種と比べて格段に高分解能かつ高輝度な二次電子像や反射電子像を短時間で得られる走査型電子顕微鏡を実現することが可能となる。 By applying the electron gun of the present invention to a scanning electron microscope, a scanning electron microscope capable of obtaining secondary electron images and reflected electron images with much higher resolution and higher brightness than conventional models in a short time is realized. It becomes possible.
また、半導体プロセスにおける微細加工パターンの観察や寸法測長を行う測長ＳＥＭの電子光学系の基本構成も図８と同様であるため、本発明の電子銃を適用することによって、同様の効果が得られる。 In addition, since the basic configuration of the electron optical system of the length measuring SEM that performs microscopic pattern observation and dimension measurement in the semiconductor process is the same as that shown in FIG. 8, the same effect can be obtained by applying the electron gun of the present invention. can get.
なお、電界放出型電子銃を搭載する走査型電子顕微鏡の構成は図８で示したものに限定されることはなく、電界放出型電子銃の特性が十分引出せる構成であれば従来周知の構成を採用できる。 Note that the configuration of the scanning electron microscope on which the field emission electron gun is mounted is not limited to that shown in FIG. 8, and any conventionally known configuration can be used as long as the characteristics of the field emission electron gun can be sufficiently extracted. Can be adopted.
（電子ビーム応用装置への適用例２）
図９は本発明の電子銃を搭載した電子線描画装置の全体構成例である。電子光学系の基本構成は前記した走査型電子顕微鏡とほぼ同様である。電子銃から電界放射により得られた電子ビームをコンデンサレンズで絞り、対物レンズで試料上に絞込み、ナノメータオーダーのビームスポットを得る。この時、試料への電子ビーム照射のＯＮ／ＯＦＦを制御するブランキング電極の中心は、コンデンサレンズで作られるクロスオーバ点に一致した方が良い。
(Application example 2 to electron beam application equipment)
FIG. 9 shows an example of the overall configuration of an electron beam lithography apparatus equipped with the electron gun of the present invention. The basic configuration of the electron optical system is almost the same as that of the scanning electron microscope described above. An electron beam obtained by field emission from an electron gun is narrowed down with a condenser lens and narrowed down on a sample with an objective lens to obtain a beam spot of nanometer order. At this time, the center of the blanking electrode that controls ON / OFF of the electron beam irradiation to the sample is preferably coincident with the crossover point formed by the condenser lens.
電子線描画は、電子ビームをブランキング電極でＯＮ／ＯＦＦしながら、偏光・走査コイルにより試料上で電子ビームを偏光，走査させながら照射することで実施される。 Electron beam drawing is performed by irradiating an electron beam while being polarized and scanned on a sample by a polarization / scanning coil while the electron beam is turned ON / OFF by a blanking electrode.
電子線描画装置は、電子線に感応するレジストを塗布した試料基板に電子ビームを照射し、各種回路パターンを形成するものであるが、各種回路パターンの高精細化に伴い、極細プローブ径が得られる電子銃が必要になってきている。本発明の電子銃を適用することにより、従来機種に比べ、格段に高輝度かつ極細プローブ径が得られるため、高効率かつ高精細な電子線描画が可能となる。 The electron beam lithography system irradiates a sample substrate coated with a resist sensitive to electron beams with an electron beam to form various circuit patterns. An electron gun is needed. By applying the electron gun of the present invention, it is possible to obtain an extremely high brightness and ultrafine probe diameter as compared with the conventional model, so that high-efficiency and high-definition electron beam drawing is possible.
なお、図１０に示すように、本発明の電界放出型陰極を複数個搭載し、各々の陰極に独立に電圧印加できるようにすることで、多数の電子ビームを同時に試料へ照射し、一括描画できるため、描画効率を飛躍的に向上させることができる。 As shown in FIG. 10, a plurality of field emission cathodes of the present invention are mounted, and a voltage can be applied independently to each cathode, so that a large number of electron beams are simultaneously irradiated onto a sample, and batch drawing is performed. Therefore, the drawing efficiency can be greatly improved.
１…一本の繊維状炭素物質を有する導電性基材、２…電極、３…電極支持台、４…引出電極、５…加速電極、６…引出電極電源、７…加速電極電源、８…磁界レンズ、９…３価および５価の元素であるホウ素および窒素のうち少なくとも１種が含有されている一本の繊維状炭素物質、１０…導電性被覆層、１１…導電性基材先端部に形成した平坦面、１２…導電性基材、１３…電界放出型陰極、１４…電子銃、１５…アライメントコイル、１６…コンデンサレンズ、１７…非点補正コイル、１８…対物レンズ、１９…偏向，走査コイル、２０…試料、２１…二次電子検出器、２２…対物レンズ絞り、２３…試料ステージ、２４…排気系、２５…ブランカ、２６…電極支持台、２７…電極駆動回路、２８…電子レンズ、２９…偏向器、３０…電子ビーム。
DESCRIPTION OF
Claims (13)
ＳＥＭ。 A length-measuring SEM equipped with the field emission electron gun according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2005189138A JP2006049293A (en) | 2004-06-30 | 2005-06-29 | Field-emission electron gun and electron beam application apparatus using the same |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2004192454 | 2004-06-30 | ||
| JP2005189138A JP2006049293A (en) | 2004-06-30 | 2005-06-29 | Field-emission electron gun and electron beam application apparatus using the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2006049293A true JP2006049293A (en) | 2006-02-16 |
| JP2006049293A5 JP2006049293A5 (en) | 2006-03-30 |
Family
ID=36027562
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2005189138A Pending JP2006049293A (en) | 2004-06-30 | 2005-06-29 | Field-emission electron gun and electron beam application apparatus using the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2006049293A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008047309A (en) * | 2006-08-11 | 2008-02-28 | Hitachi High-Technologies Corp | Field emission type electron gun, and its operation method |
| JP2008300307A (en) * | 2007-06-04 | 2008-12-11 | Hitachi High-Technologies Corp | Electron emitting element, electron gun, and electronic beam application device using the same |
| US7732764B2 (en) | 2006-08-02 | 2010-06-08 | Hitachi, Ltd. | Field emission electron gun and electron beam applied device using the same |
| KR20220103389A (en) * | 2021-01-15 | 2022-07-22 | 씨비테크 주식회사 | An electron microscope containing an electron gun in which a vine-shaped carbon nano structure is formed |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001048509A (en) * | 1999-07-29 | 2001-02-20 | Ricoh Co Ltd | Cnt and cnt assembly, field emission type cold cathode electron emission element, its production and display device using the same electron emission element |
| JP2001357771A (en) * | 2000-06-12 | 2001-12-26 | Matsushita Electric Ind Co Ltd | Electron emission element and its manufacturing method and surface light emitting device and image display device and solid vacuum device |
| JP2003036805A (en) * | 2001-07-23 | 2003-02-07 | Kobe Steel Ltd | Micro x-ray source |
| JP2004079223A (en) * | 2002-08-12 | 2004-03-11 | Hitachi Ltd | Electron source having carbon nanotube and electron microscope as well as electron beam lithography device using the same |
| JP2004119263A (en) * | 2002-09-27 | 2004-04-15 | Matsushita Electric Ind Co Ltd | Electron emissive material and its manufacturing method and field emission device and picture drawing element using it |
| JP2004165518A (en) * | 2002-11-14 | 2004-06-10 | Ricoh Co Ltd | Electron beam lithography system and manufacturing method of principal part thereof |
| WO2004052489A2 (en) * | 2002-12-09 | 2004-06-24 | The University Of North Carolina At Chapel Hill | Methods for assembly and sorting of nanostructure-containing materials and related articles |
-
2005
- 2005-06-29 JP JP2005189138A patent/JP2006049293A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001048509A (en) * | 1999-07-29 | 2001-02-20 | Ricoh Co Ltd | Cnt and cnt assembly, field emission type cold cathode electron emission element, its production and display device using the same electron emission element |
| JP2001357771A (en) * | 2000-06-12 | 2001-12-26 | Matsushita Electric Ind Co Ltd | Electron emission element and its manufacturing method and surface light emitting device and image display device and solid vacuum device |
| JP2003036805A (en) * | 2001-07-23 | 2003-02-07 | Kobe Steel Ltd | Micro x-ray source |
| JP2004079223A (en) * | 2002-08-12 | 2004-03-11 | Hitachi Ltd | Electron source having carbon nanotube and electron microscope as well as electron beam lithography device using the same |
| JP2004119263A (en) * | 2002-09-27 | 2004-04-15 | Matsushita Electric Ind Co Ltd | Electron emissive material and its manufacturing method and field emission device and picture drawing element using it |
| JP2004165518A (en) * | 2002-11-14 | 2004-06-10 | Ricoh Co Ltd | Electron beam lithography system and manufacturing method of principal part thereof |
| WO2004052489A2 (en) * | 2002-12-09 | 2004-06-24 | The University Of North Carolina At Chapel Hill | Methods for assembly and sorting of nanostructure-containing materials and related articles |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7732764B2 (en) | 2006-08-02 | 2010-06-08 | Hitachi, Ltd. | Field emission electron gun and electron beam applied device using the same |
| JP2008047309A (en) * | 2006-08-11 | 2008-02-28 | Hitachi High-Technologies Corp | Field emission type electron gun, and its operation method |
| JP2008300307A (en) * | 2007-06-04 | 2008-12-11 | Hitachi High-Technologies Corp | Electron emitting element, electron gun, and electronic beam application device using the same |
| KR20220103389A (en) * | 2021-01-15 | 2022-07-22 | 씨비테크 주식회사 | An electron microscope containing an electron gun in which a vine-shaped carbon nano structure is formed |
| KR102581290B1 (en) * | 2021-01-15 | 2023-09-21 | 씨비테크 주식회사 | An electron microscope containing an electron gun in which a vine-shaped carbon nano structure is formed |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3832402B2 (en) | Electron source having carbon nanotubes, electron microscope and electron beam drawing apparatus using the same | |
| JP2873930B2 (en) | Carbonaceous solid structure having carbon nanotubes, electron emitter for electron beam source element composed of carbonaceous solid structure, and method of manufacturing carbonaceous solid structure | |
| JP6458727B2 (en) | Electrode material with low work function and high chemical stability | |
| Eletskii | Carbon nanotube-based electron field emitters | |
| US7777404B1 (en) | Field emission type electron gun comprising single fibrous carbon electron emitter and operating method for the same | |
| JP2015518245A5 (en) | ||
| US7732764B2 (en) | Field emission electron gun and electron beam applied device using the same | |
| CN109804450B (en) | Electron beam apparatus | |
| JP5102968B2 (en) | Conductive needle and method of manufacturing the same | |
| JP3982558B2 (en) | Electron source having carbon nanotubes, electron microscope and electron beam drawing apparatus using the same | |
| JP4029289B2 (en) | Manufacturing method of conductive needle and conductive needle manufactured by the method | |
| JP2006049293A (en) | Field-emission electron gun and electron beam application apparatus using the same | |
| JP2007179867A (en) | Electron source using fibrous carbon material | |
| JP4317779B2 (en) | Field emission electron gun and electron beam application apparatus using the same | |
| JP3525135B2 (en) | Carbon atom cluster ion generating apparatus and carbon atom cluster ion generating method | |
| JP4895938B2 (en) | Field emission electron gun and electron beam application apparatus using the same | |
| JP3423639B2 (en) | Method and apparatus for producing carbon nanotube | |
| JP2010015966A (en) | Electron-emitting element, electron gun, electron microscope device using it, and electron beam lithogrphy device | |
| JP2008047309A (en) | Field emission type electron gun, and its operation method | |
| US20060001350A1 (en) | Field emission electron gun and electron beam apparatus using the same | |
| US20100258724A1 (en) | Tip-sharpened carbon nanotubes and electron source using thereof | |
| JP3188952B2 (en) | Recovery method of carbon nanotube | |
| JP2002080211A (en) | Method of making carbon nanotube | |
| JP5335508B2 (en) | Method of forming strained aerial wiring, charged particle beam prism and manufacturing method thereof, observation method using interference fringe of charged particle beam, electron microscope and method of forming interference fringe in electron microscope | |
| JP2009129547A (en) | Field emission type electron source and electron beam application device using it |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20060213 |
|
| RD04 | Notification of resignation of power of attorney |
Free format text: JAPANESE INTERMEDIATE CODE: A7424 Effective date: 20060509 |
|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20070525 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20070525 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20100224 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20100302 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20100428 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20100706 |
|
| A02 | Decision of refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A02 Effective date: 20101102 |