201128003 六、發明說明： 【發明所屬之技術領域】 本發明係關於由融液提拉單晶而使其成長的單晶提拉 裝置。 【先前技術】 在使用柴氏（Czochralski，Cz)法的單晶提拉裝置， 從被收容於坩鍋內’透過坩鍋而被加熱的原料融液，進行 目的材料的單晶提拉。 藉由柴氏法製造單晶時，首先在坩堝充塡原料，藉由 高頻加熱法或電阻加熱法加熱坩堝融解原料。原料融解成 爲原料融液時，使在預定的結晶方位切出的種晶接觸於原 料融液表面，使種晶以預定的旋轉速度旋轉同時以預定的 速度進行提拉而使單晶成長。 此時，多半使用銦製的坩鍋。但是，銦製的坩鍋很昂 貴’成爲使單晶的製造成本推高的重要原因。在此，被提 議以比銦還便宜1 / 2〇程度的價格之鉬（Mo )來製造坩鍋 〇 於專利文獻1，記載了在真空室內設置鉬製坩鍋，於 該坩鍋的外圍，被設置了筒狀的碳製加熱器及碳製保溫體 的單晶藍寶石提拉裝置。 於專利文獻2，記載著坩鍋使用價格低的鉬（Mo )或 者鎢（W )，作爲加熱室形成構件可以使用碳氈（carbon- felt ) 成 形品及 碳氈之 藍寶石 單晶提 拉成長 裝置。 -5- 201128003 於專利文獻3，記載著於銦製坩鍋（B )的內側，使鉬 製或者鎢製坩鍋（A)以互不接觸的方式設置成雙重構造 ’把坩鍋（B )加熱至高溫，藉由以其輻射熱間接加熱坩 鍋（A) ’而可以不對坩鍋（A)造成熱損傷地有效率地 融溶原料粉末，即使使用比較廉價的鉬製或鎢製坩鍋（A )也可以使沒有夾雜物（inclusion)的高品質藍寶石單晶 成長之藍寶石單晶育成裝置。 〔先前技術文獻〕 〔專利文獻〕 〔專利文獻1〕日本專利特開昭6 1 -24 7 68 3號公報 〔專利文獻2〕日本專利特開2005- 1 934號公報 〔專利文獻3〕日本專利特開2008 - 73 5 3號公報 【發明內容】 〔發明所欲解決之課題〕 然而，在使用高頻加熱法的柴氏法，坩鍋兼具有保持 原料融液的容器的作用，以及坩鍋自體發熱而融解原料的 加熱器的作用。因此，於坩鍋混合有發熱的部分與不發熱 的部分，坩鍋內融液的溫度梯度會變得急遽。因此，成長 的單晶會產生應變。 在此，如專利文獻3那樣，被提議使坩鍋爲雙重構造 ，間接地進行加熱的方法。但是，在專利文獻3，有必要 使用昂貴的銦製坩鍋。 -6- 201128003 本發明之目的係於根據柴氏法（Czochralski，Cz)法 之單晶提拉裝置，可以使用廉價的坩鍋，同時緩和坩鍋內 的融液的溫度梯度’而抑制成長的單晶之應變。 〔供解決課題之手段〕 被適用於本發明之單晶提拉裝置，包含：具有底部及 由底部的周緣立起的壁部，收容原料融液的坩鍋、以與坩 鍋接近但不接觸地包圍坩鍋的方式設置的第1筒狀構件、 以包圍第1筒狀構件的方式設置的碳或含碳材料所構成的 第2筒狀構件、被捲繞於第2筒狀構件的外側，藉由交流電 流的供給而誘導加熱第2筒狀構件的線圈、以及被配置於 坩鍋的上方’由被收容於坩鍋的原料融液提拉柱狀的單晶 之提拉構件。 接著，特徵可以是坩鍋由鉬（Mo )、含鉬（Mo )的 合金、鎢（W)、或者含鎢（W)的合金構成的。 此外，特徵可以是第1筒狀構件係由鉬（Ta )、鎢（ W)、或者這些之中的至少一種元素的碳化物構成的。 進而，特徵可以是第2筒狀構件是由石墨構成的。 於這樣的單晶提拉裝置，特徵可以是坩鍋，作爲原料 融液收容氧化鋁融液，提拉構件，由被收容於坩鍋的氧化 鋁融液提拉柱狀的藍寶石單晶。 進而另外的特徵可以是提拉構件，由被收容於坩鍋的 氧化鋁融液提拉使成長於c軸方向的柱狀的藍寶石單晶。 201128003 〔發明之效果〕 根據本發明，於根據柴氏法（Czochralski，Cz)法之 單晶提拉裝置，可以使用廉價的坩鍋，同時可以緩和坩鍋 內的融液的溫度梯度，所以可抑制成長的單晶之應變。 【實施方式】 以下’參照附圖詳細說明本發明之實施型態。 (單晶提拉裝置1 ) 圖1係供說明本實施型態適用的單晶提拉裝置1的構成 之一例。 此單晶提拉裝置1，具備使由作爲柱狀單晶之一例之 藍寶石單晶所構成的藍寶石錠200成長之用的加熱爐10。 此加熱爐1〇，具備具有圓柱狀的外形，於其內部被形成圓 柱狀的空間的絕熱容器1 1。接著，絕熱容器11，係以組裝 锆製的絕熱材所構成的零件而被構成的。此外，加熱爐10 進而具備於內部空間收容絕熱容器11之真空室14。進而， 加熱爐10，被貫通形成於真空室14的側面，進而具備：由 真空室14的外部透過真空室14對絕熱容器1 1的內部供給氣 體之氣體供給管12’及被貫通形成於同一真空室14的側面 ，由絕熱容器Η的內部透過真空室14排出氣體至外部的氣 體排出管1 3。 於絕熱容器1 1的內側下方’被配置收容著作爲融溶氧 化鋁（A12 0 3 )而成的原料融液之—例之氧化鋁融液3 0 0的 201128003 坩鍋20。坩鍋20，具有朝向鉛直上方開口的形狀。此坩鍋 20，具有底部21、由底部21的周緣往上方立起的壁部22。 坩鍋20例如係鉬（Mo )製的。 此外，於絕熱容器1 1的內側下方且於坩鍋20的底部2 1 之下，被配置具有圓板狀外形的坩鍋支撐台1 5。此坩鍋支 撐台15，最好是與坩鍋20同樣爲鉬製的。接著，此坩鍋支 撐台15，由絕熱容器1 1的內側底面藉由轉軸（shaft ) 16支 撐。此轉軸16，也最好是與坩鍋20及坩鍋支撐台15同樣爲 鉬製的。如此般，坩鍋2〇藉由坩鍋支撐台15及轉軸16，由 絕熱容器1 1的內側底面被支撐。 進而，在絕熱容器1 1的內側且坩鍋2 0的外側，具備以 捲繞坩鍋20的壁部22的方式設置的作爲第2筒狀構件之一 例之發熱體I7。發熱體17例如係由石墨（graphite )等碳 兀素製造的。 接著’在發熱體17的內側且坩鍋20的外側，具備以捲 繞坩鍋20的壁部22的方式設置，防止發熱體17的構成材料 混入坩鍋20內的氧化鋁融液300之作爲第1筒狀構件之—例 之遮蔽體1 8。作爲遮蔽體1 8之構成材料，例如可以舉出係 由金屬之鉬（Ta)、金屬之鎢（W)、或者這些之中的至 少—種元素的碳化物。其中’遮蔽體丨8以碳化鉬（tantaHe eafbide，TaC )製造的爲佳。 亦即’坩鍋20的外側的側面，以筒狀的遮蔽體丨8、與 進而以被設於該遮蔽體1 8的外側的發熱體1 7所包圍著。 又’坩鍋2 0與遮蔽體1 8 ’係接近而被配置的，但是以 -9 - 201128003 不接觸的方式設置的。另一方面，發熱體17與遮蔽體18 ’ 係密接設置的。又，發熱體1 7與遮蔽體1 8，分別係藉由構 件由絕熱容器1 1的內側底面或內側上面固定的（未圖示） 〇 坩鍋20、遮蔽體18、發熱體17將於稍後詳述。 進而，加熱爐10，具備被繞拉於絕熱容器11的下部側 的側面外側且成爲真空室1 4的下部側的側面內側的部位之 金屬製的加熱線圈30。此加熱線圈30，係中介著絕熱容器 11而與發熱體17的側面成爲對向的方式被配置。 加熱線圈30，例如藉由中空狀的銅管構成的。此外， 加熱線圈30被繞拉爲螺旋狀，全體來看具有圓筒狀的形狀 。亦即，加熱線圈3 0的上部側之內徑與下部側的內徑幾乎 相同。藉此，藉由被繞拉的加熱線圈30被形成於其內部的 空間成爲圓柱狀。此外，通過圓柱狀的空間之加熱線圈3 0 的中心軸，成爲對水平方向幾乎垂直亦即成爲沿著鉛直方 向。 進而，加熱爐10,具備透過被設於絕熱容器11、真空 室14分別之上面的貫通孔而由上方往下伸的提拉構件之一 例之提拉棒40。此提拉棒40係以能夠進行鉛直方向的移動 與以軸爲中心的旋轉的方式被安裝的。又，被設於真空室 14的貫通孔與提拉棒40之間，設有未圖示之密封材。接著 ，於提拉棒40的鉛直下方側之端部，被安裝著供安裝、保 持使藍寶石錠2 00成長之基礎的種晶210 (參照後述之圖2 )之用的保持構件41。 -10- 201128003 此外，單晶提拉裝置1，具備使提拉棒40往鉛直上方 (箭頭A方向）提拉之用的提拉驅動部50及使提拉棒40往 箭頭B方向旋轉之用的旋轉驅動部60。此處，提拉驅動部 5 〇係以馬達等構成，可以調整提拉棒4 0之往箭頭A方向的 提拉速度。此外，旋轉驅動部60也以馬達等構成，可以調 整提拉棒40之往箭頭B方向的旋轉速度。 進而，單晶提拉裝置1，具備透過氣體供給管1 2而往 真空室1 4內部供給氣體之氣體供給部70。於本實施型態， 氣體供給部70，例如可以供給氮氣、氬氣等非活性氣體。 接著，氣體供給部70，可以調整對真空室1 4內部供給的氣 體的流量。 另一方面，單晶提拉裝置1，具備透過氣體排出管13 由真空室Μ內部排出氣體之排氣部80。排氣部80例如具備 真空泵等’可以進行真空室14內的減壓、或進行由氣體供 給部70供給的氣體之排氣。 進而另外，單晶提拉裝置i，具備對加熱線圈30供給 高頻的交流電流（在以下之說明稱爲高頻電流）之線圈電 源90。線圈電源90可以設定對加熱線圈30之高頻電流的供 給之有無以及供給的電流量、進而包括對加熱線圏3 0供給 的闻頻電流的頻率。 此外’單晶提拉裝置1具備透過提拉棒40檢測出成長 於提拉棒4〇的下部側的藍寶石錠2〇〇的重量之重量檢測部 Π 〇。此重量檢測部1 1 〇，例如被構成爲包含從前公知的測 壓兀件（load cell)等。 -11 - 201128003 接著，單晶提拉裝置1，具備前述之提拉驅動部50、 旋轉驅動部60、氣體供給部70、排氣部80以及控制線圈電 源9 0的動作之控制部1 0 〇。此外，控制部！ 〇 〇根據由重量檢 測部1 1 〇輸出的重量訊號，進行提拉的藍寶石錠200的結晶 直徑之計算，反饋至線圈電源90 ^ (藍寶石錠（ingot) 200 ) 圖2係使用圖1所示之單晶提拉裝置1所製造之藍寶石 錠200的構成之一例。 此藍寶石錠200具備：供使藍寶石錠200成長的基礎之 種晶2 1 0、延伸於種晶2 1 0的下部與此種晶2 1 0 —體化之肩 部220、延伸於此肩部220的下部與此肩部220—體化之直 胴部2 3 0、及延伸於直胴部2 3 0的下部與直胴部2 3 0 —體化 之尾部240。接著，於此藍寶石錠200，由上方亦即種晶 2 10側朝向下方亦即尾部240側藍寶石單晶成長於c軸方向 〇 此處，肩部220具有由種晶210側朝向直胴部230側徐 徐擴大其直徑的形狀。此外，直胴部23 0具有由上方朝向 下方其直徑幾乎相同的形狀。又，直胴部23 0的直徑，被 設定爲比所期望的藍寶石單晶的晶圓直徑稍大之値。接著 ，尾部240藉由從上方往下方直徑徐徐縮小，具有由上方 向下方成爲凸狀之形狀。又，於圖2’顯示具有尾部240往 直胴部2 3 0的下方突出的凸狀形狀之例’但在製造條件不 同的場合，亦有如圖2之虛線所示於直胴部23 0的下方具有 -12- 201128003 凹陷的凹狀之形狀。 又，於本實施型態，製造在C軸方向使結晶成長的藍 寶石錠2 0是因爲下述之理由。 一般而言，在藍色LED之基板材料或液晶投影機的偏 光子的保持構件等 > 多以使藍寶石單晶的垂直於c軸之面 ((0001 )面）成爲主面的方式由錠切出晶圓來使用。亦 即，由生產率的觀點來看，由把在c軸方向上使結晶成長 的藍寶石單晶之錠用來切出晶圓使用是較佳的。因此，在 本實施型態，考慮到在後續步驟的便利性，而進行使結晶 成長在C軸方向上的藍寶石錠2 00之製造。 但是，圖1所示之單晶提拉裝置1，不僅可提拉使結晶 成長於c軸方向之藍寶石錠2 0 0，亦可能提拉例如使結晶成 長於a軸方向的藍寶石錠200。此外，不限於藍寶石，亦 可能提拉各種氧化物單晶，進而提拉氧化物以外之單晶亦 爲可能》 (坩鍋20、發熱體17及遮蔽體18) 圖3係顯示圖1所示之坩鍋20、發熱體I7及遮蔽體18的 構成之一例之立體圖。 以下說明坩鍋20、發熱體1 7及遮蔽體18之位置關係。 〈增堝20> 首先，說明坩鍋20之構成。 在本實施型態，坩鍋20係藉由鉬所構成。坩鍋20，實 -13- 201128003 質上僅由鉬材料所構成，或者僅由鎢（W)材料來構成爲 佳。此外，亦可含有鉬與鎢之合金（Mo— W)、進而含有 鈮、钽等其他金屬元素。若爲鉬與鎢之合金（Mo - W)製 造的話，以含有10質量百分比〜40質量百分比之鎢者爲較 佳。使用此等之坩鍋20，均比銦製還要便宜。 底部21具有圓形狀，跨全區域爲幾乎均勻的厚度（例 如2mm〜7mm程度）。此外，壁部22具有圓筒形狀，這些 也跨全區域爲幾乎爲均句的厚度（例如2mm〜7mm程度） 〇 又，坩鍋20的內徑係由要成長的單晶的直徑來決定。 例如，在育成直徑約150mm (約6吋）藍寶石單晶的場合 ，坩鍋20的內徑約爲220mm。 〈發熱體1 7 > 其次，說明發熱體17»發熱體17，係藉由對加熱線圈 3〇供給的高頻電流而產生的磁束的一部分，透過絕熱容器 Η橫切發熱體17時，在發熱體17的壁面產生妨礙該磁場變 化的磁場，結果在發熱體17內產生渦電流。接著，於發熱 體1 7藉由渦電流（I )而產生比例於發熱體1 7的表面電阻 (R )之焦耳熱（W = I2R )，而使發熱體17發熱（誘導加 熱）。因而，發熱體1 7，以電阻値達某個程度之高者較佳 〇 此外’發熱體1 7，係爲了加熱融解被投入坩鍋20的原 料而設置的，所以需要在被投入坩鍋20的原料的融點附近 -14- 201128003 的溫度下是安定的。例如，氧化鋁的融點爲2 040°C，氧化 鋁融液3 0 0的溫度係由2 1 0 0 °C被加熱至2 4 0 0 °C。 石墨融點在3 5 0 0 °C以上具有充分的耐熱性。進而，石 墨具有可效率佳地產生誘導加熱之電阻。 因而，在本實施型態，把石墨作爲發熱體1 7來使用。 又，發熱體1 7不限於石墨，只要滿足前述要件者即可，以 含碳的材料爲較佳。 發熱體1 7的厚度，會受到由線圈電源90供給的高頻電 流的頻率影響，所以在本發明以5mm〜30mm之範圍較佳。 比30mm還要厚的話發熱體17的發熱效率會降低。亦即， 發熱體17太厚的話會產生不發熱的部分，此會奪走熱，所 以發熱體1 7的發熱效率不佳。此外比5mm還要薄的話，發 熱體17的發熱效率會降低。亦即，發熱體17太薄的話發熱 的部分變少所以被供給至加熱線圈30的高頻電流變成難以 反映於發熱量。發熱體17的厚度，較佳者爲10mm〜20mm 〇 又，石墨容易剝離同時由前述2100 °C加熱至2400 °C時 ，變成會具有蒸氣壓。接著，會發生碳氣體及碳氣體固化 的碳粒子。此發生之碳氣體及碳粒子混入坩鍋20內的氧化 鋁融液3 00時，會被取入藍寶石單晶，而成爲結晶缺陷。 此外，碳氣體及碳粒子，會還原氧化鋁融液3 0 0，而產生 氧氣（〇2)或一氧化碳（C0)。因此，與坩鍋20的鉬反 應，產生富於昇華性的鉬之氧化物。藉此，腐蝕坩鍋20， 縮短坩鍋2 0的壽命。 -15- 201128003 <遮蔽體18> 遮蔽體18，在坩鍋20的外側之壁部22與發熱體17之間 ’防止發熱體17構成材料（例如，發熱體17爲石墨的場合 之碳氣體及碳粒子）混入坩鍋2 0內的氧化鋁融液3 0 0。因 此’遮蔽體18，需要在被投入坩鍋20的原料的融點附近的 溫度保持安定，而且例如在發熱體17爲石墨的場合不會被 碳氣體及碳粒子所分解者爲較佳。 碳化鉬融點高達3 8 7 3 °C，係在高溫下安定的碳化物材 料。因而’不會被碳氣體及碳粒子所分解。因而，在本實 施型態，使用碳化钽。又，遮蔽體1 8不限於碳化鉬，只要 滿足前述要件者即可，以含碳化物之材料爲較佳。 坩鍋20與遮蔽體1 8，係接近而被配置的，但是以不接 觸的方式設置的。遮蔽體18，係藉由來自發熱體17的熱傳 導或熱輻射而被加熱的，所以坩鍋20與遮蔽體18接觸的話 ，與坩鍋20接觸的部分之溫度變高，會使坩鍋20內的氧化 鋁融液300的溫度梯度變得急峻。 另一方面，發熱體17與遮蔽體18，即使接觸亦無妨， 發熱體17與遮蔽體18局部接觸的話，該部分會變得高溫。 在此，使發熱體17與遮蔽體18密接，或者不接觸地接近配 置爲較佳。 遮蔽體18的厚度，較佳者爲0.1mm〜10mm之範圍。厚 度比10mm還厚的話，加工變難或者成本會提高。此外， 厚度比0.1 mm還要薄的話，作爲遮蔽體18強度會變脆而在 由單晶提拉裝置1內取出時（操作時）恐有破損之虞，喪 -16- 201128003 失強度面上的可信賴性。遮蔽體1 8的厚度，較佳者爲 0.3mm〜5mm之範圍。 如以上所說明的，在本實施型態，藉由加熱線圈3 0， 使發熱體17被加熱，密接或者接近於發熱體17而被配置的 遮蔽體18，藉由來自發熱體17的熱傳導及/或熱輻射而被 加熱。接著，接近於遮蔽體1 8而被配置的坩鍋20，藉由來 自被加熱的遮蔽體1 8的熱輻射而被加熱。在本實施型態， 坩鍋20僅擔任作爲保持氧化鋁融液3 00的容器之作用，加 熱器之作用則由發熱體1 7來擔任。亦即，坩鍋20成爲被間 接地加熱。 於本實施型態，坩鍋20係被間接地加熱，所以與藉由 誘導加熱而使坩鍋20擔負著作爲加熱器的角色相比，坩鍋 20內的氧化鋁融液3 00的溫度梯度被緩和了。藉此，可以 抑制育成的單晶之應變的發生。 發熱體17的側面的長度，比坩鍋20的壁部22的長度更 短亦可，較佳者爲相同於坩鍋20的壁部22的長度或者更長 ，且發熱體17的上端及下端分別設定爲比坩鍋20的上端及 下端更爲伸出，這從加熱坩鍋20的效率來看是較佳的。在 本實施型態，於坩鍋20與發熱體17之間中介著遮蔽體18， 但遮蔽體1 8的熱容量很小，所以遮蔽體1 8不能成爲加熱坩 鍋2 0的充分的熱源。亦即，加熱坩鍋2 0的熱的大部分係由 發熱體1 7供給的。在此，筒狀的發熱體1 7的側面長度，比 坩鍋20的壁部22的長度（坩鍋20的高度）更短的話，於坩 鍋20的壁部22的上部或/及下部，不會受到來自發熱體17 -17- 201128003 (包含遮蔽體18)的充分的熱輻射，坩鍋20，連帶在氧化 鋁融液3 00有產生急峻的溫度梯度之虞。 另一方面，遮蔽體18，係爲了防止發熱體17的構成材 料（例如，發熱體17爲石墨的場合之碳氣體及碳粒子）混 入坩鍋20內而設置的。由此觀點來看，遮蔽體18的上端， 被設定爲比發熱體17的上端更高。亦即，遮蔽體18的上端 ，被設定爲比發熱體17的上端更高爲較佳。又，遮蔽體18 的上端，亦可比坩鍋20的壁部22的上端更低，但坩鍋20的 壁部22的上端的高度被設爲比其更高的高度爲較佳。另一 方面，遮蔽體18的下端，至少在坩鍋20的壁部22的範圍內 即可，被設定爲比坩鍋20的壁部22的下端更低亦可。同樣 地，遮蔽體18的下端，只要在發熱體17的側面的範圍內即 可，被設定爲比發熱體17的下端更低亦可。亦即，遮蔽體 1 8，於朝向鉛直上方設置的坩鍋20的開口部分，以隔開坩 鍋20與發熱體17的方式設置。這是因爲發熱體17的構成材 料之往坩鍋20內的氧化鋁融液300的混入，係透過朝向鉛 直上方而設的坩鍋20的開口部分而產生的，所以於坩鍋2〇 的開口部分，遮蔽體1 8可以抑制發熱體1 7的構成材料的混 入即可。 (藍寶石錠200之製造方法） 圖4係供說明使用圖1所示之單晶提拉裝置1，製造圖2 所示之藍寶石錠200的步驟之一例之用的說明圖。 藍寶石錠200的製造，首先執行藉由加熱被塡充於真 -18- 201128003 空室1 4內的坩堝20內之固體氧化鋁進行融溶的融溶步驟（ 步驟1 0 1 )。 其次，執行在使種晶2〗0的下端部接觸於氧化鋁之融 液亦即氧化鋁融液3 00的狀態下進行溫度調整之種晶步驟 (步驟1 0 2 )。 接著，執行藉由使接觸於氧化鋁融液3 0 0的種晶2 1 0旋 轉（圖1之箭頭B方向）同時往上方（圖1之箭頭A方向）提 拉，在種晶210的下方形成肩部220之肩部形成步驟（步驟 103)。 接著，執行作爲透過種晶2 1 0使肩部2 2 0旋轉同時往上 方提拉，而於肩部220的下方形成直胴部230之直胴部形成 步驟（步驟104 )。 進而接著，執行藉由透過種晶2 1 0及肩部2 2 0使直胴部 2 3 0旋轉同時往上方提拉由氧化鋁融液3 0 0拉離，在直胴部 23 0的下方形成尾部24〇之尾部形成步驟（步驟105)。 接著，停止坩鍋20內的氧化鋁融液3 00的加熱執行進 行冷卻的冷卻步驟（步驟106 )，在所得到的藍寶石錠200 被冷卻後取出至真空室的外部，而結束一連串的製造步 驟。 又，如此進行所得到的藍寶石錠200，首先分別在肩 部220與直胴部23 0之邊界及在直胴部23 0與尾部240之邊界 切斷，切出直胴部23 0。其次，切出的直胴部230進而，在 與長邊方向直交的方向上切斷，成爲藍寶石單晶之晶圓（ wafer )。此時，本實施型態之藍寶石單晶200係晶體成長 -19- 201128003 於C軸方向，所以所得的晶圓的主面爲C面（（0001 )面） 。接著，所得到的晶圓被用於藍光LED或偏光子之製造等 〇 接下來，針對前述各個步驟進行具體說明。但此處由 步驟1 0 1之融溶步驟之前所執行的準備步驟開始依序說明 <準備步驟> 在準備步驟，首先準備c軸（<0001〉）之種晶210。 其次，在提拉棒40之保持構件41安裝種晶210，設定於特 定的位置。接著，在坩堝20內塡充氧化鋁之原料亦即氧化 鋁原料，將坩鍋20配置於坩鍋支撐台15上後，在真空室14 內組裝絕熱容器1 1。 接著，在不進行從氣體供給部70供給氣體的狀態下， 使用排氣部8 0減壓真空室1 4內。其後，氣體供給部7 0對真 空室14內供給特定的氣體，使真空室14的內部成爲常壓。 <融溶步驟> 在融溶步驟，氣體供給部70將特定的氣體供給至真空 室14內》又’於融溶步驟供給的氣體，亦可與準備步驟爲 相同的氣體，亦可爲不同的氣體。但是，坩鍋20例如以鉬 等容易被氧化的材料構成的場合，由氣體供給部70供給的 氣體之中混合有氧氣者爲不佳。 此時’旋轉驅動部6 0使提拉棒4 〇以第1旋轉速度旋轉 -20- 201128003 此外，線圈電源90對加熱線圈30供給高頻電流。由線 圈電源90對加熱線圈30供給高頻電流時，加熱線圈30的周 圍磁束會反覆地產生/消滅。 如此進行而在加熱線圈30產生的磁束的一部分，透過 絕熱容器11橫切發熱體17時，在發熱體17的壁面產生妨礙 該磁場變化的磁場，結果在發熱體1 7內產生渦電流。 接著，藉由來自發熱體17的熱輻射或熱傳導，使遮蔽 體18被加熱。進而，藉由來自遮蔽體18的熱輻射而使坩鍋 2 0被加熱。坩鍋2〇藉由熱傳導而使全體被加熱。 如此進行，坩堝20的底部21及壁部22被加熱，而伴此 使被收容於坩堝20內的氧化鋁被加熱至超過其融點（20 54 °C )時，坩堝2 0內氧化鋁原料亦即氧化鋁融溶，成爲氧化 鋁融液30(^ <種晶步驟> 在種晶步驟，氣體供給部70將特定的氣體供給至真空 室14內。又，於種晶步驟供給的氣體，亦可與融溶步驟爲 相同的氣體，亦可爲不同的氣體。但是，與融溶步驟同樣 ，最好是不要有氧的混入。 接著’提拉驅動部5 0使被安裝於保持構件4〗的種晶 210的下端’而使提拉棒40下降而停止於與坩堝2〇內的氧 化鋁融液3 00接觸的位置。在該狀態，線圈電源9〇根據來 自重量檢測部1 1 0的重量訊號，調節對加熱線圈3 〇供給的 -21 - 201128003 高頻電流的電流値。 <肩部形成步驟> 在肩部形成步驟，線圈電源90調節供給至加熱線圈30 的高頻電流後，在等到氧化鋁融液300的溫度安定下來爲 止暫時先保持一段時間，其後使提拉棒40以第1旋轉速度 旋轉同時以第1提拉速度來提拉》 如此一來，種晶210在其下端部浸於氧化鋁融液3 00的 狀態下被旋轉同時提拉，在種晶2 1 0的下端，形成朝向鉛 直下方擴開的肩部220。 又，在肩部220的直徑比所要的晶圓直徑更大上數個 mm程度的時間點，結束肩部形成步驟。 <直胴部形成步驟> 在直胴部形成步驟，氣體供給部70將特定的氣體供給 至真空室14內。又，於直胴部形成步驟供給的氣體，亦可 與肩部形成步驟爲相同的氣體，亦可爲不同的氣體。但是 ，與融溶步驟同樣，最好是不要有氧的混入。 此外，線圈電源90接著對加熱線圈30供給高頻電流， 透過坩堝2〇加熱氧化鋁融液3 00。 進而，提拉驅動部50以第2提拉速度提拉提拉棒40。 此處第2提拉速度，亦可爲與肩部形成步驟之第1提拉速度 相同的速度，亦可爲不同之速度。 進而此外，旋轉驅動部60使提拉棒40以第2旋轉速度 -22- 201128003 旋轉。此處，第2旋轉速度，亦可爲與肩部形成步驟之第！ 旋轉速度相同的速度，亦可爲不同之速度。 與種晶2 1 0 —體化的肩部2 2 0，在其下端部浸於氧化鋁 融液3 0 0的狀態被旋轉同時提拉，所以在肩部2 2 0的下端部 ，較佳者爲形成圓柱狀之直胴部230。直胴部23 0的直徑只 要是比所要的晶圓的直徑還大即可。 <尾部形成步驟> 在尾部形成步驟，氣體供給部7 0將特定的氣體供給至 真空室14內。又’於尾部形成步驟供給的氣體，亦可與直 胴部形成步驟爲相同的氣體，亦可爲不同的氣體。但是， 與融溶步驟同樣，最好是不要有氧的混入。 此外，線圈電源9 0接著對加熱線圈3 〇供給高頻電流， 透過坩堝2 0加熱氧化鋁融液3 0 0。 進而，提拉驅動部50以第3提拉速度提拉提拉棒40。 此處第3提拉速度’亦可爲與肩部形成步驟之第丨提拉速度 或者直胴部形成步驟之第2提拉速度相同的速度，亦可爲 與這些不同之速度。 進而此外，旋轉驅動部6 0使提拉棒4 〇以第3旋轉速度 旋轉。此處，第3旋轉速度’亦可爲與肩部形成步驟之第1 旋轉速度或直胴部形成步驟之第2旋轉速度相同的速度， 亦可爲與這些不同之速度。 又’於尾部形成步驟之最初，尾部2 4 0之下端，維持 於與氧化鋁融液3 00接觸的狀態。 -23- 201128003 接著，經過特定時間之尾部形成步驟之最終階段，提 拉驅動部5〇使提拉棒4〇之提拉速度增加而使提拉棒40進而 往上方提拉，使尾部240之下端脫離氧化鋁融液3 00。藉此 ，得到圖2所示之藍寶石錠200。 <冷卻步驟> 在冷卻步驟，氣體供給部70將特定的氣體供給至真空 室14內。又，於冷卻步驟供給的氣體，亦可與尾部形成步 驟爲相同的氣體，亦可爲不同的氣體。但是，與融溶步驟 同樣，最好是不要有氧的混入。 此外，線圈電源90停止對加熱線圈30之高頻電流的供 給，中止透過坩渦20之氧化鋁融液300之加熱。 進而，提拉驅動部50停止提拉棒40的提拉，旋轉驅動 部60停止提拉棒40的旋轉。 此時，在坩鍋20內，未形成藍寶石錠200的氧化鋁以 氧化鋁融液300的形式殘留少量。因此，伴隨著加熱的停 止之坩鍋20中的氧化鋁融液300徐徐冷卻，下降至氧化鋁 的融點後在坩鍋20中固化，成爲氧化鋁之固體。 接著，在真空室14內被充分冷卻的狀態，由真空室14 內取出藍寶石錠200。 如以上說明的，在本實施型態，不是藉由加熱線圈3 0 直接加熱坩鍋20之壁部22，而是間接地加熱坩鍋20。因此 ，與藉由加熱線圈30直接加熱坩鍋20的壁部22的場合相比 ，可以緩和坩鍋2 0內的融液的溫度梯度。因而，可以抑制 -24- 201128003 藉由急遽的溫度梯度導致成長的單晶內發生的應變。 【圖式簡單說明】 圖1係供說明本實施型態適用的單晶提拉裝置的構成 之一例。 圖2係使用單晶提拉裝置所製造之藍寶石錠之構成之 一例。 圖3係顯示坩鍋、發熱體及遮蔽體的構成之一例之立 體圖。 圖4係供說明使用單晶提拉裝置製造藍寶石錠的步驟 之一例之流程圖。 【主要元件符號說明】 1 :單晶提拉裝置 I 〇 :加熱爐 II :絕熱容器 14 :真空室 1 5 :坩堝支撐台 1 6 :轉軸 17 :發熱體 18 :遮蔽體 2 0 :坩堝 3 〇 =加熱線圈 40 :提拉棒 -25- 201128003 41 :保持構件 5 0 :提拉驅動部 6 0 :旋轉驅動部 70 :氣體供給部 80 :排氣部 9 0 :線圈電源 1 0 0 :控制部 1 1 〇 :重量檢測部 200:藍寶石錠（ingot) 2 1 0 :種晶 220 :肩部 2 3 0 :直胴部 240 :尾部 3 00 :氧化鋁融液 -26BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single crystal pulling device for growing a single crystal by a melt. [Prior Art] A single crystal pulling device using a Czochralski (Cz) method is used to carry out single crystal pulling of a target material from a raw material melt which is accommodated in a crucible and is heated by a crucible. When a single crystal is produced by the Czochralski method, the raw material is first heated, and the raw material is melted by a high-frequency heating method or a resistance heating method. When the raw material is melted into a raw material melt, the seed crystal cut out at a predetermined crystal orientation is brought into contact with the surface of the raw material melt, and the seed crystal is rotated at a predetermined rotational speed while being pulled at a predetermined speed to grow the single crystal. At this time, most of the crucibles made of indium are used. However, the crucible made of indium is very expensive, which is an important reason for increasing the manufacturing cost of the single crystal. Here, it is proposed to manufacture a crucible having a molybdenum (Mo) which is less than 1 / 2 便宜 cheaper than indium. Patent Document 1 discloses that a molybdenum crucible is provided in a vacuum chamber, on the periphery of the crucible. A single crystal sapphire pulling device provided with a cylindrical carbon heater and a carbon heat insulator. Patent Document 2 describes molybdenum (Mo) or tungsten (W) having a low cost in a crucible, and a carbon-fel molded article and a carbon felt-based sapphire single crystal pulling and growing device can be used as the heating chamber forming member. . In the case of the indium-made crucible (B), the molybdenum or tungsten crucible (A) is placed in a double structure so as not to be in contact with each other. Heating to a high temperature, by indirectly heating the crucible (A)' with its radiant heat, the raw material powder can be efficiently melted without causing thermal damage to the crucible (A), even if a relatively inexpensive molybdenum or tungsten crucible is used ( A) A sapphire single crystal growth apparatus in which a high-quality sapphire single crystal without inclusions can be grown. [PRIOR ART DOCUMENT] [Patent Document 1] Japanese Patent Laid-Open Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. 2005- 1 934 (Patent Document 3) Japanese Patent JP-A-2008-73 5 3 SUMMARY OF THE INVENTION [Problems to be Solved by the Invention] However, in the Chai method using the high-frequency heating method, the crucible has the function of holding the container of the raw material melt, and the crucible The pot itself heats up and melts the material as a heater. Therefore, in the crucible where the hot portion is mixed with the non-heated portion, the temperature gradient of the melt in the crucible becomes impatient. Therefore, the grown single crystal will generate strain. Here, as in Patent Document 3, a method in which the crucible is a double structure and indirectly heated is proposed. However, in Patent Document 3, it is necessary to use an expensive indium crucible. -6- 201128003 The object of the present invention is a single crystal pulling device according to the Czochralski (Cz) method, which can suppress the growth by using an inexpensive crucible while relaxing the temperature gradient of the melt in the crucible. Strain of single crystal. [Means for Solving the Problem] The single crystal pulling device to which the present invention is applied includes a bottom portion and a wall portion rising from the periphery of the bottom portion, and a crucible containing the raw material melt, which is close to but not in contact with the crucible The first tubular member provided to surround the crucible, the second tubular member formed of carbon or a carbonaceous material provided to surround the first tubular member, and wound around the outer side of the second tubular member The coil that heats the second tubular member is induced by the supply of the alternating current, and the pulling member that is placed on the upper side of the crucible to pull the columnar single crystal from the raw material contained in the crucible. Next, the feature may be that the crucible is composed of molybdenum (Mo), an alloy containing molybdenum (Mo), tungsten (W), or an alloy containing tungsten (W). Further, the first tubular member may be composed of molybdenum (Ta), tungsten (W), or a carbide of at least one of these elements. Further, it may be characterized in that the second tubular member is made of graphite. Such a single crystal pulling apparatus may be characterized by a crucible, a raw material melt containing alumina melt, a pulling member, and a columnar sapphire single crystal pulled from an aluminum oxide melt contained in a crucible. Further, another feature may be a pulling member that is pulled by an alumina melt contained in a crucible to grow a columnar sapphire single crystal grown in the c-axis direction. 201128003 [Effects of the Invention] According to the present invention, in the single crystal pulling apparatus according to the Czochralski (Cz) method, an inexpensive crucible can be used, and the temperature gradient of the melt in the crucible can be alleviated, so Suppresses the strain of a growing single crystal. [Embodiment] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. (Single crystal pulling device 1) Fig. 1 is a view showing an example of the configuration of the single crystal pulling device 1 to which the present embodiment is applied. The single crystal pulling apparatus 1 includes a heating furnace 10 for growing a sapphire ingot 200 composed of a sapphire single crystal which is an example of a columnar single crystal. This heating furnace has a heat insulating container 1 having a cylindrical outer shape and a cylindrical columnar space inside. Next, the heat insulating container 11 is constructed by assembling a component made of a heat insulating material made of zirconium. Further, the heating furnace 10 further includes a vacuum chamber 14 that accommodates the heat insulating container 11 in the internal space. Further, the heating furnace 10 is formed to penetrate the side surface of the vacuum chamber 14, and further includes a gas supply pipe 12' that supplies gas to the inside of the heat insulating container 1 through the vacuum chamber 14 through the outside of the vacuum chamber 14, and is formed in the same The side of the vacuum chamber 14 is exhausted from the inside of the heat insulating container 透过 through the vacuum chamber 14 to the external gas discharge pipe 13 . In the lower side of the inside of the heat insulating container 1', the 201128003 crucible 20 of the alumina melt 300, which is a raw material melt which is made of molten aluminum oxide (A12 0 3 ), is placed. The crucible 20 has a shape that opens toward the vertical upper side. This crucible 20 has a bottom portion 21 and a wall portion 22 which rises upward from the periphery of the bottom portion 21. The crucible 20 is made of, for example, molybdenum (Mo). Further, under the inner side of the heat insulating container 1 1 and below the bottom portion 2 1 of the crucible 20, a crucible support table 15 having a disk-shaped outer shape is disposed. The crucible support 15 is preferably made of molybdenum similarly to the crucible 20. Next, the crucible support 15 is supported by a shaft 16 from the inner bottom surface of the heat insulating container 1 1. The spindle 16, preferably also made of molybdenum, is the same as the crucible 20 and the crucible support 15. In this manner, the crucible 2 is supported by the inner bottom surface of the heat insulating container 1 by the crucible support table 15 and the rotating shaft 16. Furthermore, the heat generating body I7 which is one example of the second cylindrical member provided to wind the wall portion 22 of the crucible 20 is provided inside the heat insulating container 1 1 and outside the crucible 20 . The heating element 17 is made of, for example, carbon such as graphite. Then, the inside of the heating element 17 and the outside of the crucible 20 are provided so as to be wound around the wall portion 22 of the crucible 20, and the constituent material of the heating element 17 is prevented from being mixed into the crucible 20. The first cylindrical member is an example of a shielding body 18. The constituent material of the shielding body 18 may, for example, be a metal molybdenum (Ta), a metallic tungsten (W), or a carbide of at least one of these elements. Among them, the shielding body 8 is preferably made of tantalum carbide (TaC). That is, the side surface on the outer side of the crucible 20 is surrounded by a cylindrical shielding body 8 and a heating element 17 provided outside the shielding body 18. Further, the crucible 20 is disposed close to the shielding body 1 8 ', but is disposed so as not to be in contact with -9 - 201128003. On the other hand, the heating element 17 is provided in close contact with the shielding body 18'. Further, the heating element 17 and the shielding body 18 are respectively fixed by a member (not shown) from the inner bottom surface or the inner upper surface of the heat insulating container 1 (the illustration), the shielding body 18, and the heating element 17 will be slightly Detailed later. Furthermore, the heating furnace 10 is provided with a metal heating coil 30 which is wound around the outer side surface of the lower side of the heat insulating container 11 and which is located on the inner side of the lower side of the vacuum chamber 14 . This heating coil 30 is disposed so as to face the side surface of the heat generating body 17 by interposing the heat insulating container 11. The heating coil 30 is formed, for example, by a hollow copper tube. Further, the heating coil 30 is wound in a spiral shape and has a cylindrical shape as a whole. That is, the inner diameter of the upper side of the heating coil 30 is almost the same as the inner diameter of the lower side. Thereby, the space formed inside the heating coil 30 that is wound is cylindrical. Further, the central axis of the heating coil 30 passing through the cylindrical space becomes almost vertical in the horizontal direction, that is, in the vertical direction. Further, the heating furnace 10 is provided with a pulling rod 40 which is an example of a pulling member which is passed through a through hole provided in the upper surface of the heat insulating container 11 and the vacuum chamber 14 and which is extended downward from above. This pulling rod 40 is attached so as to be movable in the vertical direction and in the rotation centered on the shaft. Further, a sealing member (not shown) is provided between the through hole provided in the vacuum chamber 14 and the pulling rod 40. Then, at the end portion on the vertical lower side of the pull-up bar 40, a holding member 41 for mounting and holding the seed crystal 210 (see Fig. 2 to be described later) on which the sapphire ingot 200 is grown is attached. -10- 201128003 In addition, the single crystal pulling device 1 includes a pulling drive unit 50 for pulling the pulling rod 40 vertically upward (in the direction of the arrow A) and rotating the pulling rod 40 in the direction of the arrow B. Rotary drive unit 60. Here, the pulling drive unit 5 is configured by a motor or the like, and the pulling speed of the pulling rod 40 in the direction of the arrow A can be adjusted. Further, the rotation driving unit 60 is also constituted by a motor or the like, and the rotation speed of the pulling rod 40 in the direction of the arrow B can be adjusted. Further, the single crystal pulling device 1 includes a gas supply unit 70 that supplies a gas to the inside of the vacuum chamber 14 through the gas supply pipe 12 . In the present embodiment, the gas supply unit 70 can supply, for example, an inert gas such as nitrogen or argon. Next, the gas supply unit 70 can adjust the flow rate of the gas supplied to the inside of the vacuum chamber 14. On the other hand, the single crystal pulling device 1 includes an exhaust portion 80 that discharges gas from the inside of the vacuum chamber through the gas discharge pipe 13. The exhaust unit 80 includes, for example, a vacuum pump or the like that can perform pressure reduction in the vacuum chamber 14 or exhaust gas supplied from the gas supply unit 70. Further, the single crystal pulling device i includes a coil power source 90 that supplies a high-frequency alternating current (referred to as a high-frequency current in the following description) to the heating coil 30. The coil power supply 90 can set the supply of the high-frequency current to the heating coil 30 and the amount of current supplied, and further includes the frequency of the frequency-frequency current supplied to the heating coil 30. Further, the single crystal pulling device 1 is provided with a weight detecting portion Π that detects the weight of the sapphire ingot 2 成长 which is grown on the lower side of the pulling rod 4 through the pulling rod 40. The weight detecting unit 1 1 〇 is configured, for example, to include a load cell or the like known in the past. -11 - 201128003 Next, the single crystal pulling device 1 includes the above-described pulling drive unit 50, the rotation driving unit 60, the gas supply unit 70, the exhaust unit 80, and the control unit 10 that controls the operation of the coil power supply 90. . In addition, the control department!计算 Calculating the crystal diameter of the sapphire ingot 200 according to the weight signal outputted by the weight detecting unit 1 1 ,, and feeding back to the coil power source 90 ^ (sapphire ingot 200) Fig. 2 is as shown in Fig. An example of the configuration of the sapphire ingot 200 manufactured by the single crystal pulling device 1. The sapphire ingot 200 includes: a seed crystal 2 10 that is a base for growing the sapphire ingot 200, a lower portion 220 that extends over the seed crystal 2 10 and a shoulder portion 220 that is formed by the crystal 2 10 , and extends over the shoulder portion The lower portion of the 220 and the shoulder portion 220 are formed by a straight portion 2300, and a lower portion 240 extending from the lower portion of the straight portion 203 and the straight portion 203. Next, the sapphire ingot 200 is grown in the c-axis direction from the upper side, that is, the seed crystal 2 10 side toward the lower side, that is, the tail portion 240 side sapphire single crystal. Here, the shoulder portion 220 has the seed crystal 210 side toward the straight portion 230. The side slowly expands its diameter shape. Further, the straight portion 23 0 has a shape in which the diameter is almost the same from the upper side toward the lower side. Further, the diameter of the straight portion 23 0 is set to be slightly larger than the diameter of the wafer of the desired sapphire single crystal. Then, the tail portion 240 is gradually reduced in diameter from the upper side to the lower side, and has a shape which is convex from the upper side to the lower side. 2' shows a convex shape having a tail portion 240 protruding downward from the straight portion 2300. However, when the manufacturing conditions are different, there is also a straight line portion 23 as shown by a broken line in FIG. The lower part has a concave shape of -12-201128003. Further, in the present embodiment, the sapphire ingot 20 which grows crystals in the C-axis direction is produced for the following reasons. In general, the substrate material of the blue LED or the holding member of the polarizer of the liquid crystal projector is often made of an ingot such that the surface of the sapphire single crystal perpendicular to the c-axis (the (0001) plane) becomes the main surface. Cut out the wafer for use. That is, from the viewpoint of productivity, it is preferable to use an ingot of sapphire single crystal which grows crystals in the c-axis direction for cutting out the wafer. Therefore, in the present embodiment, the manufacture of the sapphire ingot 200 which grows the crystal in the C-axis direction is performed in consideration of the convenience in the subsequent step. However, the single crystal pulling apparatus 1 shown in Fig. 1 can not only lift the crystal sapphire ingot in the c-axis direction, but also lift the sapphire ingot 200 which is crystallized in the a-axis direction. In addition, it is not limited to sapphire, and it is also possible to lift various oxide single crystals, and it is also possible to extract single crystals other than oxides (the crucible 20, the heating element 17 and the shielding body 18). A perspective view of an example of the configuration of the crucible 20, the heating element I7, and the shielding body 18. The positional relationship between the crucible 20, the heating element 17 and the shielding body 18 will be described below. <增埚20> First, the constitution of the crucible 20 will be described. In this embodiment, the crucible 20 is composed of molybdenum. Shabu-shabu 20, Shi -13- 201128003 is preferably composed of only molybdenum material or only tungsten (W) material. Further, it may contain an alloy of molybdenum and tungsten (Mo-W), and further contains other metal elements such as ruthenium and osmium. In the case of an alloy of molybdenum and tungsten (Mo - W), it is preferred to contain 10% by mass to 40% by mass of tungsten. The use of such crucibles 20 is even cheaper than indium. The bottom portion 21 has a circular shape and is almost uniform in thickness across the entire region (e.g., about 2 mm to 7 mm). Further, the wall portion 22 has a cylindrical shape, and these are also almost uniform thicknesses (for example, about 2 mm to 7 mm) across the entire area. Further, the inner diameter of the crucible 20 is determined by the diameter of the single crystal to be grown. For example, in the case of cultivating a sapphire single crystal having a diameter of about 150 mm (about 6 Å), the inner diameter of the crucible 20 is about 220 mm. <The heating element 1 7 > Next, the heating element 17»the heating element 17 is described as a part of the magnetic flux generated by the high-frequency current supplied to the heating coil 3〇, and when the heating element 17 is cut through the heat insulating container, A magnetic field that hinders the change of the magnetic field is generated on the wall surface of the heating element 17, and as a result, an eddy current is generated in the heating element 17. Then, the heating element 17 generates Joule heat (W = I2R) proportional to the surface resistance (R) of the heating element 17 by the eddy current (I), and causes the heating element 17 to generate heat (induced heating). Therefore, it is preferable that the heating element 17 is higher in resistance to a certain degree, and the heating element 17 is provided for heating and melting the raw material that is put into the crucible 20, so that it is required to be put into the crucible 20 The melting point of the raw material is stable near the temperature of -14 to 201128003. For example, the melting point of alumina is 2 040 ° C, and the temperature of aluminum oxide melt 300 is heated from 2 1 0 0 ° C to 2 400 ° C. The graphite melting point has sufficient heat resistance above 3500 °C. Further, the graphite has an electric resistance which can efficiently induce heating. Therefore, in the present embodiment, graphite is used as the heating element 17. Further, the heating element 17 is not limited to graphite, and a material containing carbon is preferable as long as the above requirements are satisfied. Since the thickness of the heating element 17 is affected by the frequency of the high-frequency current supplied from the coil power supply 90, it is preferably in the range of 5 mm to 30 mm in the present invention. If it is thicker than 30 mm, the heat generation efficiency of the heating element 17 is lowered. That is, if the heating element 17 is too thick, a portion which does not generate heat will be generated, which will take away heat, so that the heating efficiency of the heating element 17 is not good. Further, if it is thinner than 5 mm, the heat generation efficiency of the heat generating body 17 is lowered. In other words, when the heating element 17 is too thin, the portion where heat is generated is reduced, so that the high-frequency current supplied to the heating coil 30 is hardly reflected in the amount of heat generation. The thickness of the heating element 17 is preferably 10 mm to 20 mm. Further, when the graphite is easily peeled off and heated from 2100 ° C to 2400 ° C, the vapor pressure is obtained. Then, carbon particles in which carbon gas and carbon gas are solidified occur. When the carbon gas and the carbon particles which are generated are mixed into the aluminum oxide melt in the crucible 20, they are taken into the sapphire single crystal and become crystal defects. In addition, carbon gas and carbon particles reduce the alumina melt 300 to produce oxygen (〇2) or carbon monoxide (C0). Therefore, in response to the molybdenum of the crucible 20, a sublimation-rich molybdenum oxide is produced. Thereby, the crucible 20 is corroded, and the life of the crucible 20 is shortened. -15- 201128003 <Shielding body 18> The shielding body 18 prevents the heating element 17 from forming a material between the wall portion 22 on the outer side of the crucible 20 and the heating element 17 (for example, carbon gas in the case where the heating element 17 is graphite) And carbon particles) mixed with aluminum oxide melt 300 in the crucible. Therefore, the shielding body 18 needs to be kept at a temperature near the melting point of the raw material to be introduced into the crucible 20, and for example, when the heating element 17 is graphite, it is preferably not decomposed by carbon gas or carbon particles. The molybdenum carbide has a melting point of up to 3 8 7 3 °C and is a stable carbide material at high temperatures. Therefore, it is not decomposed by carbon gas and carbon particles. Thus, in this embodiment, tantalum carbide is used. Further, the shielding body 18 is not limited to molybdenum carbide, and a material containing a carbide is preferable as long as the above requirements are satisfied. The crucible 20 is disposed adjacent to the shielding body 18, but is disposed in a non-contact manner. The shielding body 18 is heated by heat conduction or heat radiation from the heating element 17, so that when the crucible 20 is in contact with the shielding body 18, the temperature of the portion in contact with the crucible 20 becomes high, and the crucible 20 is inside. The temperature gradient of the alumina melt 300 becomes severe. On the other hand, the heating element 17 and the shielding body 18 may be in contact with each other, and if the heating element 17 is partially in contact with the shielding body 18, the portion may become high in temperature. Here, it is preferable that the heating element 17 is in close contact with the shielding body 18 or in a non-contact manner. The thickness of the shielding body 18 is preferably in the range of 0.1 mm to 10 mm. If the thickness is thicker than 10 mm, the processing becomes difficult or the cost is increased. In addition, if the thickness is thinner than 0.1 mm, the strength of the shielding body 18 becomes brittle, and when it is taken out by the single crystal pulling device 1 (during operation), it may be damaged, and the loss-strength surface is lost. Trustworthiness. The thickness of the shielding body 18 is preferably in the range of 0.3 mm to 5 mm. As described above, in the present embodiment, the heating body 17 is heated by the heating coil 30, and the shielding body 18 which is disposed in close contact with or close to the heating element 17 is thermally conducted by the heating element 17 and / or heat radiation is heated. Next, the crucible 20 disposed close to the shielding body 18 is heated by the heat radiation from the heated shielding body 18. In the present embodiment, the crucible 20 functions only as a container for holding the alumina melt 300, and the heater functions as the heating element 17. That is, the crucible 20 is heated by the ground. In the present embodiment, since the crucible 20 is indirectly heated, the temperature gradient of the alumina melt 300 in the crucible 20 is compared with the role of the crucible 20 as a heater by induction heating. Was moderated. Thereby, the occurrence of strain of the grown single crystal can be suppressed. The length of the side surface of the heating element 17 may be shorter than the length of the wall portion 22 of the crucible 20, preferably the length or longer than the wall portion 22 of the crucible 20, and the upper end and the lower end of the heating element 17 It is set to protrude more than the upper end and the lower end of the crucible 20, respectively, which is preferable from the viewpoint of the efficiency of heating the crucible 20. In the present embodiment, the shielding body 18 is interposed between the crucible 20 and the heating element 17, but the heat capacity of the shielding body 18 is small, so that the shielding body 18 cannot be a sufficient heat source for heating the crucible 20. That is, most of the heat for heating the crucible 20 is supplied from the heating element 17. Here, the length of the side surface of the cylindrical heat generating body 17 is shorter than the length of the wall portion 22 of the crucible 20 (the height of the crucible 20), and is in the upper portion and/or the lower portion of the wall portion 22 of the crucible 20, It does not receive sufficient heat radiation from the heating element 17 -17- 201128003 (including the shielding body 18), and the crucible 20 is associated with a sharp temperature gradient in the alumina melt 300. On the other hand, the shielding body 18 is provided to prevent the constituent material of the heating element 17 (for example, carbon gas and carbon particles in the case where the heating element 17 is graphite) from being mixed into the crucible 20. From this point of view, the upper end of the shielding body 18 is set to be higher than the upper end of the heating element 17. That is, the upper end of the shielding body 18 is set to be higher than the upper end of the heating element 17. Further, the upper end of the shielding body 18 may be lower than the upper end of the wall portion 22 of the crucible 20, but the height of the upper end of the wall portion 22 of the crucible 20 is preferably set to be higher than the height. On the other hand, the lower end of the shielding body 18 may be at least in the range of the wall portion 22 of the crucible 20, and may be set to be lower than the lower end of the wall portion 22 of the crucible 20. Similarly, the lower end of the shielding body 18 may be set to be lower than the lower end of the heating element 17 as long as it is within the range of the side surface of the heating element 17. That is, the shielding body 18 is disposed at an opening portion of the crucible 20 disposed vertically upward to separate the crucible 20 from the heating element 17. This is because the constituent material of the heating element 17 is mixed with the alumina melt 300 in the crucible 20, and is transmitted through the opening portion of the crucible 20 provided vertically upward, so that the opening of the crucible 2 is In part, the shielding body 18 can suppress the incorporation of the constituent materials of the heating element 17 . (Manufacturing Method of Sapphire Ingot 200) Fig. 4 is an explanatory view for explaining an example of the step of manufacturing the sapphire ingot 200 shown in Fig. 2 by using the single crystal pulling device 1 shown in Fig. 1. For the manufacture of the sapphire ingot 200, a melting step (step 1 0 1 ) of melting the solid alumina in the crucible 20 in the empty chamber 14 of the true -18-201128003 is first performed. Next, a seeding step of performing temperature adjustment in a state where the lower end portion of the seed crystal 2 "0" is brought into contact with the melt of alumina, that is, the alumina melt 300 (step 1 0 2 ) is performed. Next, the seed crystal 2 10 0 that is in contact with the alumina melt 300 (rotation in the direction of the arrow B) is simultaneously pulled upward (in the direction of the arrow A in FIG. 1), below the seed crystal 210. A shoulder forming step of forming the shoulder 220 is formed (step 103). Next, a straight-line forming step (step 104) is performed in which the shoulder portion 220 is rotated while passing through the seed crystal 2 10 and the straight portion 230 is formed below the shoulder portion 220. Then, the straight 胴 2 3 0 is rotated by the seed crystal 2 10 and the shoulder 2 2 0 while being pulled upward, and pulled away by the alumina melt 300, below the straight portion 23 0 A tail forming step of forming the tail portion 24 is formed (step 105). Next, the cooling of the alumina melt 300 in the crucible 20 is stopped to perform the cooling step (step 106), and the obtained sapphire ingot 200 is cooled and taken out to the outside of the vacuum chamber, thereby ending a series of manufacturing steps. . Further, the sapphire ingot 200 thus obtained is first cut at the boundary between the shoulder portion 220 and the straight portion 23 0 and at the boundary between the straight portion 23 0 and the tail portion 240, and the straight portion 23 0 is cut out. Next, the cut straight portion 230 is further cut in a direction orthogonal to the longitudinal direction to form a wafer of sapphire single crystal. At this time, the sapphire single crystal 200-based crystal of the present embodiment is grown in the C-axis direction, so that the main surface of the obtained wafer is the C-plane ((0001) plane). Next, the obtained wafer is used for the manufacture of a blue LED or a polarizer, etc. Next, each step described above will be specifically described. Here, the preparation step performed before the melting step of the step 101 is described in the following. <Preparation step> In the preparation step, the seed crystal 210 of the c-axis (<0001>) is first prepared. Next, the seed crystal 210 is attached to the holding member 41 of the pulling rod 40, and is set at a specific position. Next, an aluminum oxide raw material, which is a raw material of alumina, is placed in the crucible 20, and the crucible 20 is placed on the crucible support table 15, and then the heat insulating container 11 is assembled in the vacuum chamber 14. Next, in a state where the gas is not supplied from the gas supply unit 70, the inside of the vacuum chamber 14 is decompressed using the exhaust unit 80. Thereafter, the gas supply unit 70 supplies a specific gas to the inside of the vacuum chamber 14 to make the inside of the vacuum chamber 14 a normal pressure. <melting step> In the melting step, the gas supply unit 70 supplies a specific gas into the vacuum chamber 14 and the gas supplied in the melting step may be the same gas as the preparation step, or may be Different gases. However, when the crucible 20 is made of a material which is easily oxidized such as molybdenum, it is not preferable that oxygen is mixed into the gas supplied from the gas supply unit 70. At this time, the rotary driving unit 60 rotates the pulling rod 4 第 at the first rotation speed. -20- 201128003 Further, the coil power supply 90 supplies a high-frequency current to the heating coil 30. When the high-frequency current is supplied to the heating coil 30 by the coil power supply 90, the peripheral magnetic flux of the heating coil 30 is repeatedly generated/destroyed. When a part of the magnetic flux generated in the heating coil 30 is cross-cut through the heat insulating container 11 as described above, a magnetic field that hinders the change of the magnetic field is generated on the wall surface of the heat generating body 17, and an eddy current is generated in the heat generating body 17 as a result. Next, the shield 18 is heated by heat radiation or heat conduction from the heat generating body 17. Further, the crucible 20 is heated by heat radiation from the shield 18. The crucible 2 is heated by heat conduction. In this way, the bottom portion 21 and the wall portion 22 of the crucible 20 are heated, and when the alumina contained in the crucible 20 is heated to exceed its melting point (20 54 ° C), the alumina raw material in the crucible 20 That is, the alumina is melted and becomes the alumina melt 30 (^ < seeding step > In the seeding step, the gas supply unit 70 supplies a specific gas into the vacuum chamber 14. Further, in the seeding step The gas may be the same gas as the melting step, or may be a different gas. However, as with the melting step, it is preferable not to mix oxygen. Next, the pulling drive unit 50 is mounted and held. The lower end ' of the seed crystal 210 of the member 4 is lowered, and the pulling rod 40 is lowered to stop at a position in contact with the alumina melt 300 in the crucible 2 00. In this state, the coil power source 9 is based on the weight detecting portion 1 The weight signal of 10 adjusts the current -21 of the high-frequency current supplied to the heating coil 3 -21. - <shoulder forming step> In the shoulder forming step, the coil power supply 90 adjusts the supply to the heating coil 30 After the frequency current, wait until the temperature of the alumina melt 300 After being set, it is temporarily held for a while, and then the pulling rod 40 is rotated at the first rotation speed while being pulled at the first pulling speed. Thus, the seed crystal 210 is immersed in the alumina melt at the lower end portion thereof. In the state of 30,000, it is rotated while pulling, and at the lower end of the seed crystal 210, a shoulder portion 220 is formed which is expanded downward. Further, the diameter of the shoulder portion 220 is larger than the diameter of the desired wafer. At the time point of the degree of mm, the shoulder forming step is ended. <Direct straight portion forming step> In the straight portion forming step, the gas supply portion 70 supplies a specific gas into the vacuum chamber 14. Further, it is formed in the straight portion The gas supplied in the step may be the same gas as the shoulder forming step, or may be a different gas. However, as with the melting step, it is preferable not to mix oxygen. Further, the coil power source 90 is followed by the heating coil. 30, the high-frequency current is supplied, and the alumina melt is heated by 坩埚2〇. Further, the pulling drive unit 50 pulls up the pulling rod 40 at the second pulling speed. Here, the second pulling speed may be The speed at which the first pulling speed of the shoulder forming step is the same Further, the rotation drive unit 60 rotates the pulling rod 40 at the second rotation speed -22-201128003. Here, the second rotation speed may be the step of forming the shoulder portion! The speed at which the rotation speed is the same may be different speeds. The shoulder portion 2 2 0 which is formed with the seed crystal 2 1 0 is rotated while being pulled in the state in which the lower end portion is immersed in the alumina melt 300 . Therefore, at the lower end portion of the shoulder portion 220, a cylindrical straight portion 230 is preferably formed. The diameter of the straight portion 23 0 may be larger than the diameter of the desired wafer. > In the tail forming step, the gas supply unit 70 supplies a specific gas into the vacuum chamber 14. Further, the gas supplied in the tail forming step may be the same gas as the straight portion forming step, or may be a different gas. However, as with the melting step, it is preferable not to mix with oxygen. Further, the coil power supply 90 then supplies a high-frequency current to the heating coil 3 ,, and heats the alumina melt 300 through the 坩埚20. Further, the pulling drive unit 50 lifts the pulling rod 40 at the third pulling speed. Here, the third pulling speed ' may be the same as the second pulling speed of the shoulder forming step or the second pulling speed of the straight portion forming step, or may be a speed different from these. Further, the rotation driving unit 60 rotates the pulling rod 4 〇 at the third rotation speed. Here, the third rotation speed ' may be the same speed as the first rotation speed of the shoulder forming step or the second rotation speed of the straight portion forming step, or may be a speed different from these. Further, at the beginning of the tail forming step, the lower end of the tail portion 240 is maintained in contact with the alumina melt 300. -23- 201128003 Next, after the final stage of the tail forming step of the specific time, the pulling drive unit 5 increases the pulling speed of the pulling rod 4〇, and the pulling rod 40 is further pulled upward, so that the tail portion 240 The lower end is separated from the alumina melt 3 00. Thereby, the sapphire ingot 200 shown in Fig. 2 is obtained. <Cooling Step> In the cooling step, the gas supply unit 70 supplies a specific gas into the vacuum chamber 14. Further, the gas supplied in the cooling step may be the same gas as the tail forming step, or may be a different gas. However, as with the melting step, it is best not to mix with oxygen. Further, the coil power supply 90 stops the supply of the high-frequency current to the heating coil 30, and stops the heating of the alumina melt 300 passing through the vortex 20. Further, the pulling drive unit 50 stops the pulling of the pulling rod 40, and the rotation driving unit 60 stops the rotation of the pulling rod 40. At this time, in the crucible 20, the alumina in which the sapphire ingot 200 is not formed remains as a small amount in the form of the alumina melt 300. Therefore, the alumina melt 300 in the crucible 20 with the stop of heating is gradually cooled, lowered to the melting point of the alumina, and solidified in the crucible 20 to become a solid of alumina. Next, in a state where the vacuum chamber 14 is sufficiently cooled, the sapphire ingot 200 is taken out from the inside of the vacuum chamber 14. As described above, in the present embodiment, the crucible 20 is not indirectly heated by the heating of the wall portion 22 of the crucible 20 by the heating coil 30. Therefore, the temperature gradient of the melt in the crucible 20 can be alleviated as compared with the case where the wall portion 22 of the crucible 20 is directly heated by the heating coil 30. Therefore, it is possible to suppress the strain occurring in the grown single crystal by the violent temperature gradient from -24 to 201128003. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing an example of a configuration of a single crystal pulling device to which the present embodiment is applied. Fig. 2 is an example of the constitution of a sapphire ingot manufactured using a single crystal pulling device. Fig. 3 is a perspective view showing an example of a configuration of a crucible, a heating element, and a shielding body. Fig. 4 is a flow chart for explaining an example of a step of manufacturing a sapphire ingot using a single crystal pulling device. [Description of main components] 1 : Single crystal pulling device I 〇: Heating furnace II: Insulation container 14 : Vacuum chamber 1 5 : 坩埚 Support table 1 6 : Rotary shaft 17 : Heating element 18 : Shielding body 2 0 : 坩埚 3 〇 = heating coil 40 : pulling rod - 25 - 201128003 41 : holding member 5 0 : pulling drive unit 6 0 : rotary drive unit 70 : gas supply unit 80 : exhaust unit 9 0 : coil power supply 1 0 0 : control unit 1 1 〇: weight detecting unit 200: sapphire ingot 2 1 0 : seed crystal 220: shoulder 2 3 0 : straight portion 240: tail 3 00: alumina melt -26