JP2002234795A - Lithium calcium aluminum fluoride single crystal and method for producing the same - Google Patents
Lithium calcium aluminum fluoride single crystal and method for producing the sameInfo
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、大口径のフッ化リ
チウムカルシウムアルミニウム単結晶及びその製造方法
に関する。[0001] The present invention relates to a large-diameter lithium calcium aluminum fluoride single crystal and a method for producing the same.
【０００２】[0002]
【従来の技術】半導体製造装置用のフォトリソグラフィ
ーなどのレーザー加工の分野では、より精密に加工する
必要から、紫外光を利用することが多くなってきてい
る。しかしながら、レンズ、プリズム、ハーフミラー、
窓材等の光学部材に用いられる硝材として従来から使用
されている石英ガラスでは、紫外光に対する内部透過率
が低くなるなどの問題があるため石英ガラス以外の硝材
が望まれるようになってきている。こうしたなか、波長
が200nmよりも短い、いわゆる真空紫外光に対しては石
英ガラス以外の硝材としてフッ化物系単結晶が使用され
ている。2. Description of the Related Art In the field of laser processing such as photolithography for semiconductor manufacturing equipment, ultraviolet light is increasingly used because of the need for more precise processing. However, lenses, prisms, half mirrors,
In the case of quartz glass conventionally used as a glass material used for optical members such as window materials, there is a problem that the internal transmittance with respect to ultraviolet light is low, so that a glass material other than quartz glass has been desired. . Among these, fluoride single crystals are used as glass materials other than quartz glass for so-called vacuum ultraviolet light having a wavelength shorter than 200 nm.
【０００３】フッ化リチウムカルシウムアルミニウム単
結晶は融液からの回転引き上げ（CZ）法で育成されるこ
とが知られている。直径約25mmの結晶が作製されてお
り、結晶性についても良質であることが報告されている
（J.Cryst.Growth,197(1999)896-900.参照）。また、直
径50mmの結晶の製造方法についても報告されている（特
願平2000-245797号）。[0003] It is known that lithium calcium aluminum fluoride single crystal is grown by a rotation pulling (CZ) method from a melt. A crystal having a diameter of about 25 mm has been prepared, and it has been reported that the crystallinity is also good (see J. Cryst. Growth, 197 (1999) 896-900). Also, a method for producing a crystal having a diameter of 50 mm has been reported (Japanese Patent Application No. 2000-245797).
【０００４】しかし、さらに形状が大型化された場合
は、融液表面半径方向の温度勾配が大きくなる傾向があ
り、結晶製造中の結晶と融液の固液界面形状を安定に保
つことが難しくなる。結果として、結晶内部に残留ひず
みが発生し、さらに細かい気泡の発生することがあっ
た。However, when the shape is further enlarged, the temperature gradient in the radial direction of the melt surface tends to increase, and it is difficult to stably maintain the solid-liquid interface shape between the crystal and the melt during crystal production. Become. As a result, residual strain was generated inside the crystal, and fine bubbles were sometimes generated.
【０００５】また使用するるつぼ直径が約130mmとな
り、融液量も増大するため、結晶製造中の融液の下がり
が大きくなり、結晶製造中の温度条件が変化することが
分かった。結果として、結晶と融液との境界付近におけ
る温度条件が不安定となり、育成途中から結晶内に不純
物が偏析したり、細かい気泡が発生したりすることがあ
った。また、これらの欠陥は育成中に消失しづらく、結
晶後半の結晶性に影響を与えることが分かった。Further, it was found that the diameter of the crucible used was about 130 mm, and the amount of the melt increased, so that the drop of the melt during the production of the crystal became large and the temperature conditions during the production of the crystal changed. As a result, the temperature condition near the boundary between the crystal and the melt becomes unstable, and impurities may be segregated in the crystal during the growth or fine bubbles may be generated. In addition, it was found that these defects hardly disappear during the growth, and affect the crystallinity in the latter half of the crystal.
【０００６】結晶欠陥の少ない良質単結晶を得るには、
結晶肩部から直胴部そして下端部への形状変化が制御さ
れる必要がある。その為には一般に自動形状制御装置が
用いられる。これは、ロードセルで結晶重量を測定し、
その変化率を設定値になるようにるつぼ加熱出力を調整
するシステムである。In order to obtain a high quality single crystal having few crystal defects,
The shape change from the crystal shoulder to the straight body and the lower end needs to be controlled. For this purpose, an automatic shape control device is generally used. This measures the weight of the crystal with a load cell,
This is a system that adjusts the crucible heating output so that the rate of change becomes a set value.
【０００７】[0007]
【発明が解決しようとする課題】しかし、結晶製造中の
固液界面形状が安定でない場合、製造している結晶に加
わる浮力にばらつきが生じ、ロードセルによる結晶重量
測定値が正確な値を示さなかった。結果として、結晶の
形状制御が困難であり、大口径のフッ化リチウムカルシ
ウムアルミニウム単結晶を製造することはできなかっ
た。However, when the solid-liquid interface shape during the production of the crystal is not stable, the buoyancy applied to the crystal being produced varies, and the measured value of the crystal weight by the load cell does not show an accurate value. Was. As a result, it was difficult to control the shape of the crystal, and a large-diameter lithium calcium aluminum fluoride single crystal could not be produced.
【０００８】それ故に本発明の課題は、大口径のフッ化
リチウムカルシウムアルミニウム単結晶の製造を可能に
する製造方法、及びそれにより製造された単結晶を提供
することにある。[0008] It is therefore an object of the present invention to provide a method for producing a single crystal of lithium calcium aluminum fluoride having a large diameter and a single crystal produced thereby.
【０００９】[0009]
【課題を解決するための手段】本発明者は、半導体製造
装置用のフォトリソグラフィーに使用するレンズ、プリ
ズム、ハーフミラー、窓材等の光学部材に有用である大
口径フッ化リチウムカルシウムアルミニウム単結晶の作
製方法を検討した結果、フッ化リチウムカルシウムアル
ミニウム原料の混合比をモル比でLiF：CaF2：AlF3 = 1.
05〜1.20：1：1.05〜1.20となるように混合し、フッ化
リチウムカルシウムアルミニウム単結晶を製造する際、
フッ化リチウムカルシウムアルミニウム種結晶の回転数
を製造する結晶径に応じてほぼ比例的に10〜20rpmで制
御し、さらにフッ化リチウムカルシウムアルミニウム単
結晶製造中にるつぼに満たされている融液面が一定とな
るようにるつぼを動かすことが有効であることを見いだ
した。SUMMARY OF THE INVENTION The present inventors have developed a large-diameter lithium calcium aluminum fluoride single crystal useful for optical members such as lenses, prisms, half mirrors, and window materials used in photolithography for semiconductor manufacturing equipment. As a result of studying the preparation method of LiF: CaF 2 : AlF 3 = 1.
When mixed so that the ratio becomes 05 to 1.20: 1: 1.05 to 1.20, and manufactures lithium calcium aluminum fluoride single crystal,
The rotation speed of the lithium calcium aluminum fluoride seed crystal is controlled in proportion to 10 to 20 rpm according to the crystal diameter to be produced, and the melt surface filled in the crucible during the production of the lithium calcium aluminum fluoride single crystal is increased. It has been found that moving the crucible so that it is constant is effective.
【００１０】即ち、本発明の大口径フッ化リチウムカル
シウムアルミニウム単結晶製造方法は、原料のLiF、CaF
2、AlF3の混合比がモル比でLiF：CaF2：AlF3 = 1.05〜
1.20：1：1.05〜1.20となるように混合粉末フッ化物原
料を準備し、10-6torr以上の高真空を保ちながら、粉末
フッ化物原料を室温から500〜1000℃の範囲の温度まで
加熱し、炉内において原料中に含まれる水分・酸素を除
去し、原料を融解後、作製炉内にフロン系ガスを導入
し、融液あるい溶液表面に発生する不純物及び融液ある
いは溶液内に存在する不純物と、作製炉内のフロン系ガ
スとを、不純物を除去するのに十分な時間反応させるこ
とによって不純物を除去し、得られた融液あるいは溶液
にLiCaAlF6の種結晶を接触させ、この種結晶を徐々に引
き上げる際、種結晶の回転数を製造する結晶径に応じて
ほぼ比例的に10〜20rpmにて制御し、結晶製造中の融液
面が一定となるように融液を上昇させることを特徴とす
る。That is, the method for producing a single crystal of large-diameter lithium calcium aluminum fluoride according to the present invention uses the raw materials LiF and CaF
2, LiF in a mixing ratio of the molar ratio of AlF 3: CaF 2: AlF 3 = 1.05~
1.20: 1: Prepare mixed powder fluoride raw material so as to be 1.05 to 1.20, and heat powder fluoride raw material from room temperature to a temperature in the range of 500 to 1000 ° C while maintaining a high vacuum of 10 -6 torr or more. After removing water and oxygen contained in the raw material in the furnace, melting the raw material, introducing a chlorofluorocarbon gas into the manufacturing furnace, impurities generated on the melt or solution surface and present in the melt or solution The impurities to be removed and the CFC-based gas in the production furnace are reacted for a time sufficient to remove the impurities, thereby removing the impurities.The resulting melt or solution is brought into contact with a LiCaAlF 6 seed crystal, and When the seed crystal is gradually pulled up, the rotation speed of the seed crystal is controlled in proportion to 10 to 20 rpm almost in proportion to the crystal diameter to be manufactured, and the melt is raised so that the melt surface during the crystal manufacturing becomes constant. It is characterized by making it.
【００１１】[0011]
【発明の実施の形態】以下に、本発明の実施の形態に係
るフッ化物バルク単結晶の製造方法を説明する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for manufacturing a bulk fluoride single crystal according to an embodiment of the present invention will be described.
【００１２】（ａ）混合粉末フッ化物原料の準備 原料のLiF、CaF2、AlF3の混合比がモル比でLiF：CaF2：
AlF3 = 1.05〜1.20：1：1.05〜1.20となるように混合粉
末フッ化物原料を準備する。これは原料の混合比をLi
F、AlF3側にずらすことを意味する。上記条件を外れる
場合透明でクラックやインクルージョン等のない単結晶
はできない。(A) Preparation of Mixed Powder Fluoride Raw Material The mixing ratio of the raw materials LiF, CaF 2 , and AlF 3 is LiF: CaF 2 :
A mixed powder fluoride raw material is prepared so that AlF 3 = 1.05 to 1.20: 1: 1.05 to 1.20. This means that the mixing ratio of the raw materials is Li
It means shifting to F, AlF 3 side. If the above conditions are not met, a single crystal which is transparent and free from cracks and inclusions cannot be obtained.
【００１３】（ｂ）粉末フッ化物原料の溶解、水分及び
酸素の除去 10-6torr以上の高真空を保ちながら、粉末フッ化物原料
を室温から500〜1000℃の範囲の所定の温度まで加熱
し、炉内において原料中に含まれる水分・酸素を除去す
る。(B) Dissolution of the powdery fluoride raw material, removal of water and oxygen While maintaining a high vacuum of 10 -6 torr or more, the powdery fluoride raw material is heated from room temperature to a predetermined temperature in the range of 500 to 1000 ° C. Then, moisture and oxygen contained in the raw material are removed in the furnace.
【００１４】この場合、粉末フッ化物原料は所望の単結
晶の組成に応じて適宜選択して用いる、粒度等も特に制
限が無く当業者であれば適宜設定できる範囲である。ま
た、10-6torr以上の高真空とするのは水分及び酸素の除
去を容易とするためである10 -6torr未満だと十分に水分
を除去できない。In this case, the powdery fluoride raw material has a desired single bond.
The particle size and the like are particularly controlled according to the composition of the crystal.
There is no limit, and the range can be appropriately set by those skilled in the art. Ma
T, 10-6High vacuum above torr is used to remove moisture and oxygen.
10 to make it easier to leave -6Sufficient moisture if less than torr
Cannot be removed.
【００１５】粉末フッ化物原料を室温から500℃以上で
例えば1000℃の範囲内の所定の温度まで加熱し、原料中
に含まれる水分・酸素を除去する。500℃未満であると
十分な効果が望めず、また上限温度は水分・酸素の除去
という観点から設定し、例えば1000℃とする。The powdery fluoride raw material is heated from room temperature to a predetermined temperature in the range of 500 ° C. or more, for example, 1000 ° C., to remove water and oxygen contained in the raw material. If the temperature is lower than 500 ° C., a sufficient effect cannot be expected, and the upper limit temperature is set from the viewpoint of removing moisture and oxygen, for example, 1000 ° C.
【００１６】(ｃ) 不純物の除去 原料を融解後、作製炉内にフロン系ガスを導入し、融液
又は溶液表面に発生する不純物及び融液又は溶液内に存
在する不純物と、作製炉内のフロン系ガスとを、不純物
を除去するのに十分な時間反応させることによって不純
物を除去する。フロン系ガスであれば本工程で用いるこ
とができるが、例えばCF４を用いることができる。また
フロン系ガスと他のガス、例えばC2H6との混合ガスを用
いることもできる。「不純物を除去するのに十分な時
間」とは、例えば30分以内等とすることができる。(C) Removal of impurities After the raw material is melted, a fluorocarbon-based gas is introduced into the production furnace, and impurities generated on the surface of the melt or the solution and impurities present in the melt or the solution are compared with impurities in the production furnace. The impurities are removed by reacting with a chlorofluorocarbon-based gas for a time sufficient to remove the impurities. As long as a chlorofluorocarbon-based gas can be used in this step, for example, CF 4 can be used. Also, a mixed gas of a chlorofluorocarbon-based gas and another gas, for example, C 2 H 6 can be used. "Sufficient time to remove impurities" can be, for example, within 30 minutes.
【００１７】（ｄ）融液成長法によるフッ化物バルク単
結晶の製造 得られた融液あるいは溶液にLiCaAlF6の種結晶を接触さ
せ、この種結晶を徐々に引き上げる際、種結晶の回転数
を製造する結晶径に応じてほぼ比例的に10〜20rpmの範
囲で調整する。これは、結晶製造中の結晶と融液との固
液界面形状を安定化させるためのもので、結晶径が大き
くなるにつれて種結晶の回転数を大きくすることで結晶
と融液との固液界面形状を安定化させることができる。
例えば結晶のネック部径5mmにおいて種結晶回転数10rpm
とし直胴部径75mmにおいて種結晶回転数20rpmとするも
のである。直径３インチ以上のフッ化リチウムカルシウ
ムアルミニウム単結晶を製造する際、種結晶の回転数を
ある値に一定とした場合、結晶製造中の結晶と融液との
固液界面形状が不安定となるため、結晶径の制御が不安
定となり、結果として、透明でクラックやインクルージ
ョンのない単結晶はできない。(D) Production of Bulk Fluoride Single Crystal by Melt Growth Method When a seed crystal of LiCaAlF 6 is brought into contact with the obtained melt or solution and the seed crystal is gradually pulled up, the number of rotations of the seed crystal is increased. It is adjusted in the range of 10 to 20 rpm almost proportionally according to the crystal diameter to be manufactured. This is to stabilize the shape of the solid-liquid interface between the crystal and the melt during crystal production, and to increase the number of rotations of the seed crystal as the crystal diameter increases, thereby increasing the solid-liquid The interface shape can be stabilized.
For example, at the neck diameter of the crystal of 5 mm, the seed crystal rotation speed is 10 rpm
The seed crystal rotation speed is 20 rpm at a straight body diameter of 75 mm. When producing a lithium calcium aluminum fluoride single crystal having a diameter of 3 inches or more, if the number of revolutions of the seed crystal is fixed to a certain value, the shape of the solid-liquid interface between the crystal and the melt during crystal production becomes unstable. Therefore, the control of the crystal diameter becomes unstable, and as a result, a single crystal that is transparent and free from cracks and inclusions cannot be obtained.
【００１８】（ｅ）るつぼの上昇 結晶製造中の結晶と融液との境界付近の温度条件を安定
化するため、融液面が一定となるように融液を上昇させ
フッ化リチウムカルシウムアルミニウム単結晶を製造す
る。これは、結晶製造中の結晶と融液の境界付近の温度
条件を安定化させるためのもので、結晶製造中に融液面
が一定となるようにるつぼの上昇を行わなかった場合、
透明でクラックやインクルージョン等のない単結晶はで
きない。(E) Raising the crucible In order to stabilize the temperature conditions near the boundary between the crystal and the melt during the production of the crystal, the melt is raised so that the melt surface becomes constant, and lithium calcium aluminum fluoride is added. Produce crystals. This is to stabilize the temperature conditions near the boundary between the crystal and the melt during crystal production.If the crucible is not raised so that the melt surface is constant during crystal production,
A single crystal that is transparent and free from cracks and inclusions cannot be formed.
【００１９】なお、得られた単結晶の相は粉末Ｘ線解析
（XRD）で、またOH−基の存在の有無はFT-IRにより調べ
た。[0019] Incidentally, the phase of single crystals obtained in the powder X-ray analysis (XRD), also OH - presence or absence of group was examined by FT-IR.
【００２０】（実施例）純度4NのLiF、CaF2、AlF3市販
粉末原料をモル比でLiF： CaF2：AlF3 = 1.10：1：1.10
となるように秤量し、それらを混合せずに直径130mmの
るつぼ内に充填した。原料の全重量は3000gであった。
そのまま図１に示すホットゾーン構成の単結晶育成炉内
にるつぼを置き、10-6torr程度まで真空に引き、そのま
ま約700℃程度まで真空状態で加熱した。(Embodiment) LiF, CaF 2 , and AlF 3 having a purity of 4N are commercially available as raw materials in a molar ratio of LiF: CaF 2 : AlF 3 = 1.10: 1: 1.10.
And weighed such that they were not mixed and filled into a crucible having a diameter of 130 mm. The total weight of the raw materials was 3000g.
The crucible was placed in a single crystal growth furnace having a hot zone configuration as shown in FIG. 1 and was evacuated to about 10 −6 torr, and heated as it was to about 700 ° C. in a vacuum.
【００２１】ここでCF4ガスを単結晶育成炉に導入し
た。その後、 昇温し、粉末原料を融解し、そのまま30
分、液体状態で保った。この時、液体表面に現れた不純
物が、CF 4ガスと反応することにより、全て消滅した。
液体に種結晶を接触させ、ａ軸方向に引き上げ速度0.8m
m/hで、回転数は製造する結晶径に比例してネック径5mm
においては10rpm、直胴径75mmにおいては20rpmとした。
さらに、結晶育成中に融液面が一定となるようにるつぼ
を上昇させて単結晶を育成した。Where CFFourGas into the single crystal growing furnace
Was. Then, the temperature is raised to melt the powder raw material,
Minutes, kept in liquid state. At this time, impurities appearing on the liquid surface
Things are CF FourAll disappeared by reacting with the gas.
The seed crystal is brought into contact with the liquid, and the pulling speed is 0.8m in the a-axis direction.
m / h, the number of rotations is 5 mm in neck diameter in proportion to the crystal diameter to be manufactured
Was set to 10 rpm, and 20 rpm for a straight body diameter of 75 mm.
In addition, crucibles are kept so that the melt surface is constant during crystal growth.
Was raised to grow a single crystal.
【００２２】図２に育成結晶径の変化に伴う種結晶の回
転数変化とるつぼ上昇速度変化を示す。るつぼ上昇速度
は結晶育成中の融液面が一定となるように計算して出し
た値であり、次のような計算式を用いた。まず、育成結
晶直径及びるつぼ直径をそれぞれDcrystal及びD
crucibleとする。さらに結晶引き上げ速度及びるつぼ上
昇速度をそれぞれVcrystal及びVcrucibleとすると、融
液面を一定とした場合、Vcruc ible/Vcrystal = D
crystal 2/Dcrusible 2が成り立つ。この式から計算され
た値でるつぼを上昇させた。FIG. 2 shows the change in the number of rotations of the seed crystal and the change in the crucible rising speed with the change in the diameter of the grown crystal. The crucible rising speed is a value calculated and calculated so that the melt surface during crystal growth is constant, and the following formula was used. First, the diameter of the grown crystal and the diameter of the crucible are D crystal and D, respectively.
crucible . Further, assuming that the crystal pulling speed and the crucible rising speed are V crystal and V crucible , respectively, when the melt surface is fixed, V cruc ible / V crystal = D
crystal 2 / D crusible 2 holds. The crucible was raised with the value calculated from this formula.
【００２３】これらの条件で育成した単結晶は、直径約
75mm、長さ約200mmで、気泡、クラック、スキヤツタリ
ングセンターなどの無い、透明な高品質大口径フッ化リ
チウムカルシウムアルミニウム単結晶であった。結晶内
にはレーザー特性の劣化をもたらすOH-の存在は一切観
察されなかった。The single crystal grown under these conditions has a diameter of about
It was a transparent, high-quality, large-diameter lithium calcium aluminum fluoride single crystal with a size of 75 mm and a length of about 200 mm, free from bubbles, cracks, and scattering centers. The crystal leads to degradation of the laser characteristics OH - presence of was observed at all.
【００２４】（比較例１）純度4NのLiF、CaF2、AlF3市
販粉末原料をモル比でLiF：CaF2：AlF3 = 1.10：1：1.1
0となるように秤量し、それらを混合せずに坩堝内に充
填した。原料の全重量は3000gであった。上記原料を溶
解後、種結晶を接触させ、ａ軸方向に引き上げ速度0.8m
m/h、回転数8rpm一定で引き上げた。それ以外は実施例
と同様の手段及び条件で結晶を育成した。(Comparative Example 1) LiF, CaF 2 , and AlF 3 commercially available raw materials having a purity of 4N were mixed at a molar ratio of LiF: CaF 2 : AlF 3 = 1.10: 1: 1.1.
They were weighed so as to be 0, and they were filled in a crucible without mixing. The total weight of the raw materials was 3000g. After dissolving the above-mentioned raw materials, the seed crystal is brought into contact, and the pulling speed in the a-axis direction is 0.8 m
The speed was raised at a constant speed of 8 rpm at m / h. Otherwise, crystals were grown by the same means and under the same conditions as in the examples.
【００２５】得られた結晶形状は直胴部直径75mmで長さ
200mmで、直胴部において結晶形状の制御が困難とな
り、多量のインクルージョンが発生した。The obtained crystal shape has a straight body diameter of 75 mm and a length of 75 mm.
At 200 mm, it was difficult to control the crystal shape in the straight body, and a large amount of inclusion occurred.
【００２６】（比較例２）純度4NのLiF、CaF2、AlF3市
販粉末原料をモル比でLiF：CaF2：AlF3 = 1.10：1：1.1
0となるように秤量し、それらを混合せずに坩堝内に充
填した。原料の全重量は3000gであった。上記原料を溶
解後、種結晶を接触させ、ａ軸方向に引き上げ速度0.8m
m/h、回転数25rpm一定で引き上げた。それ以外は実施例
と同様の手段及び条件で結晶を育成した。Comparative Example 2 LiF, CaF 2 , and AlF 3 commercially available powder materials having a purity of 4N were mixed at a molar ratio of LiF: CaF 2 : AlF 3 = 1.10: 1: 1.1.
They were weighed so as to be 0, and they were filled in a crucible without mixing. The total weight of the raw materials was 3000g. After dissolving the above-mentioned raw materials, the seed crystal is brought into contact, and the pulling speed in the a-axis direction is 0.8 m.
m / h, rotation speed was constantly increased at 25 rpm. Otherwise, crystals were grown by the same means and under the same conditions as in the examples.
【００２７】得られた結晶形状は直胴部直径75mmで長さ
200mmで、直胴部において結晶径状の制御が困難とな
り、多量のインクルージョンが発生した。The obtained crystal shape has a straight body diameter of 75 mm and a length of 75 mm.
With a diameter of 200 mm, it became difficult to control the crystal diameter in the straight body, and a large amount of inclusions occurred.
【００２８】（比較例３）純度4NのLiF、CaF2、AlF3市
販粉末原料をモル比でLiF：CaF2：AlF3 = 1.10：1：1.1
0となるように秤量し、それらを混合せずに坩堝内に充
填した。原料の全重量は3000gであった。上記原料を溶
解後、種結晶を接触させ、ａ軸方向に引き上げ速度0.8m
m/h、回転数は製造する結晶径に比例してネック径5mmに
おいては10rpm、直胴径75mmにおいては20rpmとした。ま
た結晶育成中のるつぼの上昇は行わなかった。それ以外
は実施例と同様の手段及び条件で結晶を育成した。Comparative Example 3 LiF, CaF 2 , and AlF 3 commercially available powder materials having a purity of 4N were used in a molar ratio of LiF: CaF 2 : AlF 3 = 1.10: 1: 1.1.
They were weighed so as to be 0, and they were filled in a crucible without mixing. The total weight of the raw materials was 3000g. After dissolving the above-mentioned raw materials, the seed crystal is brought into contact, and the pulling speed in the a-axis direction is 0.8 m
m / h and the number of rotations were 10 rpm for a neck diameter of 5 mm and 20 rpm for a straight body diameter of 75 mm in proportion to the crystal diameter to be produced. The crucible was not raised during crystal growth. Otherwise, crystals were grown by the same means and under the same conditions as in the examples.
【００２９】得られた結晶形状は直胴部直径75mmで長さ
200mmで、直胴部の途中から多量のインクルージョンが
発生した。The obtained crystal shape has a straight body diameter of 75 mm and a length of 75 mm.
At 200mm, a large amount of inclusions occurred in the middle of the straight body.
【００３０】[0030]
【発明の効果】以上説明したように、本発明によれば、
通常の育成方法では作製困難であった直径３インチのフ
ッ化リチウムカルシウムアルミニウム単結晶の作成が可
能となった。更に、半導体製造装置用のフォトリソグラ
フィーに使用するレンズ、プリズム、ハーフミラー、窓
材等の光学部材として大口径フッ化リチウムカルシウム
アルミニウム単結晶を提供できることが示された、等多
くの重大な効果が認められた。As described above, according to the present invention,
It has become possible to produce a lithium calcium aluminum fluoride single crystal having a diameter of 3 inches, which was difficult to produce by a normal growing method. Furthermore, it has been shown that a large-diameter lithium calcium aluminum fluoride single crystal can be provided as an optical member such as a lens, a prism, a half mirror, and a window material used for photolithography for a semiconductor manufacturing apparatus. Admitted.
【図１】結晶育成に用いたホットゾーン構成図である。FIG. 1 is a configuration diagram of a hot zone used for growing a crystal.
【図２】育成結晶径に伴う種結晶回転数変化及びるつぼ
上昇速度変化の図である。FIG. 2 is a diagram showing a change in the number of rotations of a seed crystal and a change in a rising speed of a crucible according to a grown crystal diameter.
１ カーボンヒーター ２ カーボン保温材 ３ 結晶引き上げ軸 ４ 育成結晶 ５ 融液 ６ 白金るつぼ Vcrystal 結晶引き上げ速度 Vcrucible るつぼ上昇速度 REFERENCE SIGNS LIST 1 carbon heater 2 carbon heat insulating material 3 crystal pulling shaft 4 growing crystal 5 melt 6 platinum crucible V crystal crystal pulling speed V crucible crucible raising speed
───────────────────────────────────────────────────── フロントページの続き (72)発明者 島村 清史 宮城県仙台市太白区三神峯１−３−２− 302 (72)発明者 福田 承生 宮城県仙台市泉区虹ノ丘２−６−７ (72)発明者 猿倉 信彦 愛知県岡崎市竜美南２−３−１ 明大寺住 宅６−403 Ｆターム(参考） 4G077 AA02 CF07 EC02 EC10 EH08 EH09 PF33 PF35 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kiyoshi Shimamura 1-2-3-2 Mikamine, Taishiro-ku, Sendai-city, Miyagi Prefecture (72) Inventor Seio Fukuda 2-6-7 Ninooka, Izumi-ku, Sendai-city, Miyagi Prefecture (72) Inventor Nobuhiko Sarukura 2-3-1 Tatsumi Minami, Okazaki City, Aichi Prefecture 6-403 Myodaiji Residence F-term (reference) 4G077 AA02 CF07 EC02 EC10 EH08 EH09 PF33 PF35
Claims (2)
比でLiF：CaF2：AlF3= 1.05〜1.20：1：1.05〜1.20とな
るように混合粉末フッ化物原料を準備し、 10-6torr以上の高真空を保ちながら、粉末フッ化物原料
を室温から500℃以上で所定の温度の範囲内の温度まで
加熱し、炉内において原料中に含まれる水分・酸素を除
去し、 原料を融解後、作製炉内にフロン系ガスを導入し、融液
あるいは溶液表面に発生する不純物及び融液あるいは溶
液内に存在する不純物と、作製炉内のフロン系ガスと
を、不純物を除去するのに十分な時間反応させることに
よって不純物を除去し、 融解した原料にLiCaAlF6の種結晶を接触させ、この種結
晶を徐々に引き上げて単結晶を製造する際、製造してい
る結晶径に応じてほぼ比例的に種結晶の回転数を10〜20
rpmで変化させ、引き上げ速度を0.7〜1.0mm/hとし、さ
らに結晶製造中の融液面が一定となるように融液を上昇
させることを特徴とするフッ化リチウムカルシウムアル
ミニウム単結晶の製造方法。1. A mixed powder fluoride raw material is prepared so that the mixing ratio of the raw materials LiF, CaF 2 , and AlF 3 is LiF: CaF 2 : AlF 3 = 1.05 to 1.20: 1: 1.05 to 1.20 in molar ratio. While maintaining a high vacuum of 10 -6 torr or more, the powdered fluoride raw material is heated from room temperature to a temperature of 500 ° C. or more to a temperature within a predetermined range to remove moisture and oxygen contained in the raw material in the furnace. After the raw materials are melted, a fluorocarbon gas is introduced into the production furnace, and impurities generated on the surface of the melt or solution and impurities present in the melt or solution and the fluorocarbon gas in the production furnace are removed. The impurities are removed by reacting for a sufficient time to remove them, and a LiCaAlF 6 seed crystal is brought into contact with the molten raw material, and the seed crystal is gradually pulled up to produce a single crystal. Rotation of the seed crystal approximately in proportion to
rpm, changing the pulling speed to 0.7 to 1.0 mm / h, and further raising the melt so that the melt surface during the crystal production is constant, a method for producing a lithium calcium aluminum fluoride single crystal, .
口径フッ化リチウムカルシウムアルミニウム単結晶。2. A large-diameter lithium calcium aluminum fluoride single crystal produced by the production method according to claim 1.
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| JP2001030975A JP2002234795A (en) | 2001-02-07 | 2001-02-07 | Lithium calcium aluminum fluoride single crystal and method for producing the same |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001030975A JP2002234795A (en) | 2001-02-07 | 2001-02-07 | Lithium calcium aluminum fluoride single crystal and method for producing the same |
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| JP2002234795A true JP2002234795A (en) | 2002-08-23 |
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ID=18895121
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1422322A1 (en) * | 2002-11-19 | 2004-05-26 | Tokuyama Corporation | As-grown single crystal of alkaline earth metal fluoride |
| RU2310829C2 (en) * | 2003-03-28 | 2007-11-20 | Стелла Кемифа Корпорейшн | Method of analyzing admixtures in fluoride and producing material for growing monocrystal |
| WO2012144383A1 (en) * | 2011-04-22 | 2012-10-26 | セントラル硝子株式会社 | Process for producing fluorine-containing combined salt |
| CN103570050A (en) * | 2012-09-19 | 2014-02-12 | 东北林业大学 | Lithium hexafluoride calcium aluminium material with hollow tetrakaidecahedron structure |
-
2001
- 2001-02-07 JP JP2001030975A patent/JP2002234795A/en not_active Withdrawn
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1422322A1 (en) * | 2002-11-19 | 2004-05-26 | Tokuyama Corporation | As-grown single crystal of alkaline earth metal fluoride |
| US7364715B2 (en) | 2002-11-19 | 2008-04-29 | Tokuyama Corporation | As-grown single crystal of alkaline earth metal fluoride |
| RU2310829C2 (en) * | 2003-03-28 | 2007-11-20 | Стелла Кемифа Корпорейшн | Method of analyzing admixtures in fluoride and producing material for growing monocrystal |
| WO2012144383A1 (en) * | 2011-04-22 | 2012-10-26 | セントラル硝子株式会社 | Process for producing fluorine-containing combined salt |
| JP2012232886A (en) * | 2011-04-22 | 2012-11-29 | Central Glass Co Ltd | Process for producing fluorine-containing combined salt |
| US9556037B2 (en) | 2011-04-22 | 2017-01-31 | Central Glass Company, Limited | Process for producing fluorine-containing combined salt |
| CN103570050A (en) * | 2012-09-19 | 2014-02-12 | 东北林业大学 | Lithium hexafluoride calcium aluminium material with hollow tetrakaidecahedron structure |
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