200844270 九、發明說明 【發明所屬之技術領域】 本發明係關於：被使用在半導體裝置製造的最基本基 礎材料的矽單晶的製造之單晶育成裝置，特別是，關於藉 ' 由柴可勞斯基法（Czochralski method )而育成矽單晶之 * 單晶育成裝置。 ^ 【先前技術】 在製造矽單晶（以下，有單獨記載爲「單晶」者）係 有各種的手法，但在其中一般爲柴可勞斯基法（ Czochralski method )(以下，記爲「CZ法」）。在藉由 CZ法的單晶製造，係在已被作爲減壓氛圍的爐體內，將 種晶浸漬於蓄積在石英坩鍋內的矽融液，從此狀態一邊使 坩鍋以及種晶旋轉、同時將種晶徐徐地向上方拉起。由此 ，在種晶的下方使矽的單晶成長，得到大略圓柱狀的單晶 在藉由如此的CZ法之單晶的上拉，係已知··在結晶 剖面的缺陷分布等，爲相依於結晶成長速度，也就是上拉 速度。越加快上拉速度，環狀的OSF產生區域越向外周部 移動，最終係朝向結晶有效部分的外側而被排除。反之， 因爲變慢上拉速度，而環狀的OSF產生區域係向結晶中心 部移動，最終在該中心部消滅。 OSF產生區域的內側和外側都是缺陷產生區域，但是 其外側與內係缺陷的種類不同。另外，可知：若將上拉速 -5- 200844270 度加以高速度化，則想當然而生產性提高，再加上缺陷爲 細微化。因此，作爲在結晶成長之一個方向性，是追求上 拉的高速化。 作爲用以實現高速上拉的技術，已知爲：進行熱遮蔽 體的配設。熱遮蔽體，係爲以包圍單晶的周圍的方式設置 之逆圓錐台形狀的筒狀的隔熱構件，主要是遮蔽來自坩鍋 內的融液或配置於坩鍋的外側之加熱器的輻射熱。由此， 因爲可抑制從融液上拉的單晶的加熱，所以結果上促進了 單晶的冷卻，可謀求上拉速度的高速化。 而且在最近，亦注目著：在熱遮蔽體的內側，配設： 強制地水冷的筒狀的冷卻體之技術（例如：日本特開平 1 1 -92272號公報）。藉由將在內部流通冷卻水的筒狀冷卻 體，以包圍單晶的周圍的方式設置在熱遮蔽體的內側，更 促進單晶的特別局溫部分之冷卻，可謀求上拉速度的更高 速化。 但是，在藉由如此的CZ法之單晶的育成，不可否認 地：若產生單晶的非預定落下等，則以坩鍋爲首的各種熱 區構成構件（熱遮蔽體或冷卻體等）會破損。不過，在謀 求上拉速度的高速化的零件之中，熱遮蔽體的破損並不產 生那麼大的問題。 但是，在冷卻體已破損的情況，係有引起很大的事故 之疑慮。因冷卻體的破損，流通於冷卻體的內部之冷卻水 係漏出至爐體內，若此已漏出的冷卻水與處於溫度非常高 的狀態之融液等接觸，則一口氣地產生氣化而爐體內的壓 -6- 200844270 力劇烈地上昇。也就是，有可能引起水蒸氣爆炸。另外， 即使在冷卻體不破損的情況，也有因爲經年累月的劣化等 而自然產生漏出冷卻水之情事，在此情況亦擔心有同樣的 水蒸氣爆炸。 對於如此的安全操作上的問題，在先前的單晶育成裝 置，係個別以流量計測定：流入至冷卻體的冷卻水的流量 、與從冷卻體流出的冷卻水的流量，僅以兩者的流量差而 判定冷卻水的異常漏水（例如：日本特開2002-1 04895號 公報）。此係著眼於：在冷卻體不產生漏水的情況，係向 冷卻體的冷卻水的流入量與從冷卻體的冷卻水的流出量爲 一致；另一方面，若在冷卻體產生漏水，則比起向冷卻體 的流入量而言，從冷卻體的流出量減少。藉由如此的單晶 育成裝置，可在作業中檢測出從冷卻體的漏水，結果可在 很大的事故產生之前，採取適當的處置。 【發明內容】 然而，在上述的先前的單晶育成裝置，係當合於冷卻 水的異常漏水的判定，而實際上儘管冷卻體爲健全沒有漏 水，但有對於冷卻體之冷卻水的流出入而產生流量差的結 果，被誤判爲有漏水之情事。此係起因於：向冷卻體的冷 卻水之送水壓爲因送水幫浦的能力或運轉狀況等而變爲不 安定、或從流量計的輸出受到突然雜訊的影響。若如此的 誤判斷產生，則爲了確認漏水的有無而決定中斷作業，對 安定作業引起障礙。 200844270 於是，本發明係鑑於上述的問題而爲之物，其目的爲 提供：一邊使用冷卻體而謀求上拉速度的高速化、同時可 以高精確度檢測出從該冷卻體的漏水之安定作業性優良的 單晶育成裝置。 爲了達成上述目的，由本發明的單晶育成裝置，係藉 由CZ法而在爐體內從原料融液而育成單晶之單晶育成裝 置，含有以下的構成。在爐體內包圍由原料融液被育成之 單晶，藉由在內部流通的冷卻水而被冷卻，而將前述單晶 加以冷卻之冷卻體。檢測出流入至此冷卻體的前述冷卻水 的流量之流入側流量計。檢測出從前述冷卻體流出的前述 冷卻水的流量之流出側流量計。檢測出前述爐體內的壓力 之壓力計。在藉由前述流入側流量計及前述流出側流量計 的檢測値，而算出兩者的流量差，並且藉由前述壓力計的 檢測値而算出每單位時間的壓力變動，根據前述流量差以 及前述壓力變動而判定前述冷卻水有無漏水之控制部。 如作爲如此的構成，則根據流量差及壓力變動就能判 斷來自冷卻體的冷卻水漏水，而因爲流量差、壓力變動係 個別起因於漏水的完全不同的現象，根據兩者之漏水判斷 係精確度高。 在此，若根據實用性，則前述控制部係在特定期間內 ’前述流量差及前述壓力變動爲超過了事先設定之閾値時 ’判定爲有漏水爲理想。 另外，從將莫大的事故防止於未然的觀點來看，含有 :連接於朝向前述冷卻體的前述冷卻水的流入口，在路徑 -8- 200844270 中設置了前述流入側流量計之給水 冷卻體的前述冷卻水的流出口，在 側流量計之排水管、和從前述排水 分歧管、和開閉前述給水管的路徑 述排水管的路徑，在比朝向前述分 之處，加以開閉之排水管用閥、和 之分歧管用閥；前述控制部，係在 ，則將前述給水管用閥以及前述排 爲閉狀態，並且，將前述分歧管用 態爲理想。 如藉由本發明的單晶育成裝置 出來自冷卻體的漏水，可進行安定 【實施方式】 以下，關於本發明的單晶育成 邊參照圖面同時詳細敘述。 第1圖係表示爲本發明的一實 的構成之縱剖面圖、第2圖爲該單 。如第1圖、第2圖所示地，單晶 被稱爲上拉爐，作爲構成外圍的爐 室1及上拉室2。上拉室2係比主 主室1上被配置於同軸上。 在主室1的內部，係於該中；C 係成爲雙重構造，由：被塡充多結 管、和連接於來自前述 路徑中設置了前述流出 管分歧而開放至外部之 之給水管用閥、和將前 歧管的分歧點還下流側 開閉前述分歧管的路徑 判定爲有漏水的情況時 水管用閥從開狀態切換 閥從閉狀態切換爲開狀 ，則可以高精確度檢測 的作業。 裝置的一實施形態，一 施形態的單晶育成裝置 晶育成裝置的橫剖面圖 育成裝置係一般而言亦 體，具備：圓筒狀的主 室1直徑小而較長，在 部配置坩鍋3。坩鍋3 晶矽的內側之石英坩鍋 -9- 200844270 、和嵌合於其外側之石墨製的支持坩鍋而構成。此坩鍋3 ，係支持在被稱爲托架 （pedestal )之無圖示的支持軸上 ，依照該支持軸的旋轉驅動、昇降驅動，一邊在圓周方向 上旋轉、一邊在軸方向上昇降。 在坩鍋3的外側，係以包圍坩鍋3的方式將阻抗加熱 式的加熱器4以同心圓狀地配置，在其更外側，係沿著主 室1的內面而配置著保溫筒5。加熱器4係使塡充於坩鍋 3內的多結晶矽熔融，藉由此而在坩鍋3內蓄積著矽的融 液6 〇 一方面，在坩鍋3的上方，係作爲上拉軸的線7，爲 通過上拉室2的中心部而懸吊著。線7，係藉由在設置於 上拉室2的上部之上拉機構而旋轉驅動的同時、在軸方向 被昇降驅動。在線7的下端部，係安裝著保持種晶之種晶 夾具。將被保持於種晶夾具的種晶，浸漬於坩鍋3內的融 液6，一邊使該種晶旋轉、同時應使之徐徐地上昇而藉由 驅動線7，在種晶的下方，矽的單晶8漸漸成長。 另外，在坩鍋3的上方，係以包圍單晶8的周圍之方 式，大略圓筒狀的熱遮蔽體9爲接近坩鍋3內的融液6而 被設置爲同心圓狀。此熱遮蔽體9係由石墨所構成，擔任 阻擋來自坩鍋3內的融液6或加熱器4之輻射熱的任·務。 爲了有效地發揮該熱遮蔽效果，所以熱遮蔽體9，係從下 方朝向上方徐徐地擴大直徑，將該下部插入至坩鍋3內而 使其位於坩鍋3內的融液6的上方的樣態之逆圓錐台形（ 錐形）爲理想。 -10- 200844270 在熱遮蔽體9的內側，係大略圓筒狀的冷卻體1 0被 同心圓狀地配置。冷卻體1 0係由熱傳導性良好的銅系金 屬所構成，在該內部形成流通冷卻水之通水路。在冷卻體 1 〇，係於該通水路的入口連接給水管1 4，在通水路的出口 連接排水管1 5。給水管1 4及排水管1 5亦由銅系金屬所構 成。在冷卻體1 0係通過給水管1 4而流入冷卻水，該已流 入之冷卻水係經過通水路而從冷卻體1 〇流出，通過排水 管1 5而被排出。如此，冷卻體1 〇，係由在內部流通的冷 卻水而被強制冷卻。 此冷卻體10，係配置於熱遮蔽體9的下部內，藉由特 別包圍單晶8的凝固之後的高溫部分，擔任促進該高溫部 分的冷卻之任務。而且，冷卻體1 〇亦與熱遮蔽體9同樣 地作爲：從下方朝向上方徐徐地擴大直徑之錐狀。給水管 1 4及排水管1 5，係在對冷卻體1 0不施加荷重的狀態熔接 〇 冷卻體10係，在爐體內的上拉軸周圍，藉由放射狀 地配置之複數的支持臂1 3而被支持於爐體內。支持臂1 3 係由：從主室1的上部內面，朝向爐體內中心而水平地延 伸出，從中途向下方彎曲之略逆L字形的棒狀材所構成， 冷卻體1 0，係該上緣部爲在各支持臂1 3的各先端部，藉 由螺栓等而被可裝卸地連結。各支持臂1 3，在此係藉由不 銹鋼所構成，對冷卻體1 0係藉由另外系統的通水而強制 地冷卻。 另外，在主室1，係連接：連繋於無圖示的真空幫浦 -11 - 200844270 之真空排氣管11。藉由真空幫浦的驅動，爐體的內部空氣 通過真空排氣管11而被排氣，爐體內被作爲減壓氛圍。 在真空排氣管11的路徑中，係設置著無圖示的蝶閥，藉 由此蝶閥的開閉程度而調整爐體內的壓力。蝶閥，係藉由 * 來自後述的第3圖所示之控制部22的指令而被驅動。 " 在上拉室2的上部’係連接：將Ar氣體等的惰性氣 體導入爐體內之無圖示的沖洗氣體（purge gas )導入管 I 。在爐體內，係通過沖洗氣體導入管而供給惰性氣體，爐 體內被作爲減壓下的惰性氣體氛圍。向爐體內的惰性氣體 的導入量，係藉由設置在沖洗氣體導入管的路徑中的質量 流量控制器而調整。質量流量控制器，係藉由來自後述的 第3圖所示之控制部22的指令而被驅動。 於主室1，係設置：檢測出爐體的內部壓力之壓力計 1 2。但是，爐內壓力的檢測係不限定於此，如爲可實質上 檢測出爐內壓力者亦佳，例如：檢測出被排出爐外的氣體 φ 壓力亦佳。 第3圖爲在單晶育成裝置的漏水監視系統之系統圖。 如第3圖所示地，在給水管1 4，係在路徑中設置第1流量 計17以及自動式的第1開閉閥19。第1流量計17，係檢 測出：通過給水管1 4而流入至冷卻體1 0的冷卻水之流量 。作爲第1流量計1 7係可適用超音波式之物。第1開閉 閥19，係在開狀態下打開給水管1 4的路徑，在閉狀態下 遮斷給水管1 4的路徑。在此的第1流量計1 7係被設置在 :以配管長看來，從冷卻體1 0算起 3 m以內之處，第1 -12- 200844270 開閉閥1 9係設置在第1流量計1 7的上流側。在給水管1 4 的上流區域，係配設：送出冷卻水之無圖示的送水幫浦。 同樣地，在排水管1 5，係在路徑中設置第2流量計 1 8以及自動式的第2開閉閥20。第2流量計1 8，係檢測 出：通過排水管1 5而從冷卻體1 0流出的冷卻水之流量。 作爲第2流量計1 8係可適用超音波式之物。第2開閉閥 20，係在開狀態下打開排水管1 5的路徑，在閉狀態下遮 斷排水管1 5的路徑。在此的第2流量計1 8係被設置在： 以配管長看來，從冷卻體1 〇算起 3m以內之處，第2開 閉閥20係設置在第2流量計1 8的下流側。 另外，在排水管15，係安裝：從第2流量計1 8與第 2開閉閥20之間分歧之分歧管1 6。在分歧管1 6，在路徑 中裝備著專用的自動式的第3開閉閥21。第3開閉閥21 ，係在開狀態下打開分歧管1 6的路徑，在閉狀態下遮斷 分歧管1 6的路徑。分歧管1 6的下流端，係開放於爐體的 外部。 第1流量計1 7及第2流量計1 8係連接於控制部22， 控制部22係接受：關於在第1流量計1 7、第2流量計1 8 個別檢測出的流量L1、L2之訊號。另外，在控制部22係 連接壓力計12，控制部22係接受：關於在壓力計12檢測 出之爐體內的壓力P之訊號。然後，第1開閉閥19、第2 開閉閥20及第3開閉閥21，係藉由來自控制部22的指令 而操作。 接著，說明關於如此的單晶育成裝置的結晶成長之作 -13- 200844270 業例。 在坩鍋3內裝塡多結晶矽原料1〇〇kg，之後，將爐體 內作爲2 0 0 P a的A r氛圍。藉由設置在堪鍋3的外側的加 熱器4，熔融坩鍋3內的多結晶矽原料，使用〗〇 〇方位的 種晶，而在該下方使直徑20 0mm的單晶成長。 此時’以埘鍋3內的融液6的液面水平維持於一定的 方式’隨者結晶成長而使坦鍋3徐徐地上昇。另外，在與 單晶8的旋轉方向相同方向或相反方向，使坦鍋3旋轉。 在通常的作業，係第1開閉閥1 9及第2開閉閥2 0都 作爲開狀態，另一方面，第3開閉閥2 1被作爲閉狀態。 如這麼作，則冷卻水通過已打開路徑的給水管1 4及排水 管1 5而流通到冷卻體1 0 ’強制地冷卻冷卻體1 〇。由此， 特別是強制地冷卻：單晶8之凝固之後的高溫部分。其結 果，作爲單晶8的上拉速度，可達成2mm/分以上。附帶 的，在不使用冷卻體10的情況之達成上拉速度爲1mm/ 分左右。而且，分歧管16係因爲路徑被遮斷，所以冷卻 水不流通。 在此，在以下說明關於在該作業中所進行之漏水監視 系統的動作。 第4圖，係表示在單晶育成裝置的漏水監視系統的動 作之流程圖。如第4圖所示，首先在步驟# 5 ’控制部2 2， 係逐次接受：來自第1流量計17之關於朝向冷卻體10的 冷卻水的流入流量L1之訊號、來自第2流量計1 8之關於 從冷卻體1 〇的冷卻水的流出流量L2之訊號 '以及來自壓 -14 - 200844270 力計1 2之關於爐體內的壓力p之訊號。 接著在步驟# 1 0，控制部22係在已接受的訊號之中’ 藉由關於流入流量L1及流出流量L2的訊號，而逐次算出 :流入流量L1與流出流量L2的流量差△ L ( =L1-L2)。 配合這個，藉由關於爐內壓力P的訊號，逐次算出每單位 時間的壓力變動ΔΡ。 接著在步驟# 1 5，控制部22係逐次比較：已算出的流 量差△ L與事先設定的閾値△ LB。關於對該流量差之閾値 △ LB的資訊，係被收納在控制部22所搭載的記憶體。閾 値△ LB，係如考慮第1流量計1 7及第2流量計1 8的檢測 精確度而設定則爲理想，從現在的流量計的檢測精確度以 及冷卻水量來看，係設定爲30cc/秒以上爲最佳。 配合這個，逐次比較：已算出的壓力變動ΔΡ與事先 設定的閾値ΔΡΒ。關於對該壓力變動之閾値ΔΡΒ的資訊 ，亦被收納在控制部22所搭載的記憶體。閾値△ PB，係 在對於：從冷卻體不漏水之通常的作業時的爐內壓力變動 的最大値，有2倍以上的壓力變動的情況下，判斷爲異常 的方式，設定閾値△ pB爲最佳。 在步驟#2 0，逐次判定：流量差△ L是否超過了閾値 △ LB。若在冷卻體1 0產生漏水，則因爲該漏水量係以流 量差△ L而顯現，所以在此係以流量差△ L是否超過了閾 値△ L B，而可暫時地判斷有無漏水。在流量差△ L還沒有 超過閾値△ LB的情況，係暫時地判斷爲沒有漏水而進入 步驟#2 5，另一方面，在超過的情況，係暫時地判斷爲有 -15- 200844270 漏水而進入步驟# 3 0。 在步驟#25，係逐次判定··壓力變動△ P是否超過了 閾値△ PB。若在冷卻體〗〇產生漏水，則因爲該漏水在爐 內氣化而爐體內的壓力上昇，此係以壓力變動ΔΡ而顯現 ，所以在此，係以壓力變動△ P是否超過了閾値^?8，而 可暫時地判斷有無漏水。在壓力變動△ P還沒有超過閾値 △ PB的情況，係暫時地判斷爲沒有漏水而進入步驟#5， 另一方面，在超過的情況，係暫時地判斷爲有漏水而進入 步驟#35。 在步驟#20暫時判斷爲有漏水的情況，在步驟#30，在 將流量差△ L超過閾値△ LB的時點作爲起點之特定期間內 ，逐次判定：壓力變動△ P是否超過了閾値△ PB。也就是 ，在流量差△ L超過閾値△ LB之大略同時，判定：壓力變 動△ P是否亦超過了閾値△ PB。作爲特定期間，從將向流 量計輸出的突然雜訊的影響變小之觀點來看，1秒以上爲 最佳、從將來自冷卻體的漏水之被害加以變小的觀點來看 ，設定在5秒以內爲最佳。 在流量差與壓力變動ΔΡ係大略同時地超過了閾 値△ LB、△ PB的情況，因爲成爲：在時間上同時的時脈 下，呈現出起因於漏水之不同的2個現象’所以在此情況 係可以高精確度判斷有漏水。在步驟# 3 0被判斷爲有漏水 的情況，係進入步驟# 4 0而採取合適的安全處置。 一方面，在流量差△ L與壓力變動△ P係大略同時地 不超過閾値△ LB、△ PB的情況’因爲成爲··在時間上保 -16- 200844270 有間隔的時序下，呈現出起因於漏水之不同的2個現象， 所以在此情況係實際上沒有產生漏水，可想定爲：流量差 △ L和壓力變動△ P係被誤檢測，而可以高精確度判斷沒 有漏水。在步驟#3 0被判斷爲沒有漏水的情況，係回到步 驟#5而繼續監視。 另外，在步驟#25暫時判斷爲有漏水的情況，在步驟 #3 5，在將壓力變動△ P超過閾値△ PB的時點作爲起點之 特定期間內，理想上在1秒鐘內，逐次判定：流量差△ L 是否超過了閾値ALB。也就是，在壓力變動ΔΡ超過了閾 値△ PB之大略同時，判定：流量差△ L是否亦超過了閾値 Δ LB。 在壓力變動ΔΡ和流量差AL係大略同時超過了閾値 △ PB、△ LB的情況，與步驟#3〇時相同，可以高精確度 判斷有漏水。在步驟#35被判斷爲有漏水的情況，係進入 步驟#40而採取合適的安全處置。 一方面，在壓力變動ΔΡ和流量差AL係大略同時不 超過閾値△ PB、△ LB的情況，與步驟#30時相同，可以 高精確度判斷沒有漏水。在步驟#3 5被判斷爲沒有漏水的 情況’係回到步驟#5而繼續監視。 在步驟#40，係可爲如以下的安全處置。 第1 ’控制部22係對第1開閉閥19、第2開閉閥20 以及第3開閉閥21送出指令，在將第1開閉閥19以及第 2開閉閥20從開狀態切換爲閉狀態的同時，將第3開閉閥 2 1 閉狀Sg切換爲開狀態（梦照第3圖）。若如此作，則 -17- 200844270 因爲給水管14以及排水管15的路徑被遮斷’所以向冷卻 體1 0的給水係被強制地停止。配合這個，停留在冷卻體 1 0內的冷卻水，係通過已被打開路徑的分歧管1 6而向外 部排出。在此，在冷卻體1 〇的內部已停止流動的冷卻水 ，因爲：因爐體內的高溫的影響而被加熱，劇烈地昇溫而 氣化，由此而產生體積膨脹而成爲高壓，所以通過開放至 外部的分歧管16而成爲噴出至外部。因而’可將因漏水 之水蒸氣爆炸防止於未然’提高安全性。 第2，將從冷卻體1 〇有漏水的意旨，藉由警告音的發 出或警示燈的開燈等而報知。由此，可認知：在冷卻體10 產生了漏水。 第3，停止向加熱器4之通電。配合這個，在將貯留 積融液6的坩鍋3之旋轉及昇降加以停止的同時’將懸吊 著單晶8的線7之旋轉以及昇降加以停止。 在如此的單晶育成裝置，將根據來自第1流量計1 7、 第2流量計1 8、以及壓力計1 2之檢測値的處理之一例’ 表示於以下的表1。 -18- 200844270200844270 IX. OBJECT OF THE INVENTION [Technical Field] The present invention relates to a single crystal growth apparatus for manufacturing a single crystal of a single base material used in the manufacture of a semiconductor device, and in particular, The Czochralski method is used to grow a single crystal growth apparatus for single crystals. ^ [Prior Art] There are various methods for manufacturing a single crystal (hereinafter, referred to as "single crystal" alone), but in general, it is the Czochralski method (hereinafter, " CZ method"). In the case of the single crystal by the CZ method, the seed crystal is immersed in the crucible in the quartz crucible, and the crucible and the seed crystal are rotated while being in this state. Pull the seed crystals up slowly. As a result, a single crystal of ruthenium is grown under the seed crystal to obtain a substantially cylindrical single crystal which is pulled up by a single crystal of such a CZ method, and is known as a defect distribution in a crystal cross section. It depends on the growth rate of the crystal, that is, the pull-up speed. The faster the pull-up speed is, the more the annular OSF-generating region moves toward the outer periphery, and the final portion is excluded toward the outer side of the effective portion of the crystal. On the contrary, since the pull-up speed is slowed down, the annular OSF generating region moves toward the center of the crystal and is eventually destroyed at the center portion. The inside and the outside of the OSF-generating region are both defect-producing regions, but the outer side is different from the inner-system defect. In addition, it is understood that when the speed of the pull-up is -5 - 200844270 degrees, the productivity is improved, and the defect is further reduced. Therefore, as one direction of crystal growth, the speed of pulling up is sought. As a technique for realizing high-speed pull-up, it is known to perform the arrangement of the heat shield. The heat shielding body is a cylindrical heat insulating member having a reverse truncated cone shape so as to surround the periphery of the single crystal, and mainly shields the radiant heat from the melt in the crucible or the heater disposed outside the crucible. . Thereby, since the heating of the single crystal pulled up from the melt can be suppressed, the cooling of the single crystal is promoted as a result, and the speed of the pull-up speed can be increased. Further, recently, it has been noted that a technique of forcibly cooling a cylindrical cooling body is provided on the inside of the heat shielding body (for example, Japanese Laid-Open Patent Publication No. Hei No. Hei. No. Hei. No. Hei. By providing a cylindrical cooling body that circulates cooling water therein, it is provided inside the heat shielding body so as to surround the periphery of the single crystal, thereby further promoting the cooling of the special temperature portion of the single crystal, thereby achieving a higher speed of the pull-up speed. Chemical. However, in the case of the single crystal growth by the CZ method, it is undeniable that if a single crystal is undesired, etc., various hot zone members (heat shields, heat sinks, etc.) including a crucible are formed. Will be damaged. However, in the parts requiring high speed of the pull-up speed, the damage of the heat shield does not cause such a big problem. However, in the case where the cooling body has been broken, there is a concern that a large accident has occurred. When the cooling body is broken, the cooling water flowing through the inside of the cooling body leaks into the furnace body, and if the leaked cooling water comes into contact with the melt in a state of very high temperature, the gas is ignited in the furnace body. The pressure of -6- 200844270 force rose violently. That is, it is possible to cause a water vapor explosion. In addition, even if the cooling body is not damaged, there is a case where the cooling water is naturally leaked due to deterioration over time, and in this case, the same steam explosion is also feared. In the case of such a safe operation, in the conventional single crystal growth apparatus, the flow rate of the cooling water flowing into the cooling body and the flow rate of the cooling water flowing out from the cooling body are measured by the flow meter. The abnormal flow rate of the cooling water is determined by the difference in flow rate (for example, Japanese Laid-Open Patent Publication No. 2002-1 04895). In this case, when the cooling body does not leak, the amount of the cooling water flowing into the cooling body is the same as the amount of the cooling water flowing from the cooling body. On the other hand, if the cooling body leaks, the ratio is higher. The amount of outflow from the cooling body is reduced in the amount of inflow to the cooling body. With such a single crystal growth apparatus, water leakage from the cooling body can be detected during the work, and as a result, appropriate disposal can be taken before a large accident occurs. SUMMARY OF THE INVENTION However, in the above-described single crystal growth apparatus, it is determined that the abnormal water leakage of the cooling water is combined, and actually, although the cooling body is sound and there is no water leakage, there is an outflow of cooling water to the cooling body. The result of the flow difference was misjudged as a leak. This is caused by the fact that the water supply pressure to the cooling water of the cooling body is unstable due to the capacity or operating condition of the water supply pump, or is affected by sudden noise from the output of the flow meter. If such a misjudgment occurs, it is decided to interrupt the operation in order to confirm the presence or absence of water leakage, which may cause an obstacle to the stability operation. The present invention has been made in view of the above problems, and an object of the present invention is to provide a high-accuracy pull-up speed and a high-precision detection of water leakage stability from the cooling body while using a cooling body. Excellent single crystal growth device. In order to achieve the above object, the single crystal growth apparatus of the present invention is a single crystal growth apparatus which grows a single crystal from a raw material melt by a CZ method, and has the following constitution. A single crystal which is bred by the raw material melt is surrounded in the furnace body, and is cooled by the cooling water flowing inside, and the single crystal is cooled. An inflow side flow meter that detects the flow rate of the aforementioned cooling water flowing into the cooling body. An outflow side flow meter that detects the flow rate of the cooling water flowing out from the cooling body. A pressure gauge that detects the pressure in the furnace body. The flow rate difference between the inflow side flow meter and the outflow side flow meter is calculated, and the pressure fluctuation per unit time is calculated by the detection of the pressure gauge, and the flow rate difference and the aforementioned A control unit that determines whether or not the cooling water has water leakage due to a pressure fluctuation. With such a configuration, it is possible to determine the leakage of the cooling water from the cooling body based on the flow rate difference and the pressure fluctuation, and the flow rate difference and the pressure fluctuation are caused by the completely different phenomenon of the water leakage, and the water leakage determination is accurate based on the two. High degree. Here, according to the practicability, the control unit determines that there is a water leakage when the flow rate difference and the pressure fluctuation exceed a predetermined threshold value within a predetermined period. In addition, from the viewpoint of preventing a large accident from occurring, the inlet of the cooling water that is connected to the cooling body is provided, and the water supply cooling body of the inflow side flow meter is provided in the path -8-200844270. The drain port of the cooling water, the drain pipe of the side flow meter, and the path of the drain pipe from the drain branch pipe and the path for opening and closing the water supply pipe are opened and closed by a drain valve And the control valve is a valve, and the valve for the water supply pipe and the row are closed, and the branch pipe is preferably used. The water leakage from the cooling body can be stabilized by the single crystal growth apparatus of the present invention. [Embodiment] Hereinafter, the single crystal growth of the present invention will be described in detail with reference to the drawings. Fig. 1 is a longitudinal sectional view showing a configuration of the present invention, and Fig. 2 is a view showing the same. As shown in Fig. 1 and Fig. 2, the single crystal is referred to as a pull-up furnace as a furnace chamber 1 and a pull-up chamber 2 constituting the outer periphery. The pull-up chamber 2 is disposed coaxially with respect to the main main chamber 1. In the interior of the main chamber 1 , the C system has a double structure, and is connected to a water supply pipe that is connected to the water supply pipe from the path in which the outflow pipe is branched and opened to the outside. When it is determined that there is a water leakage when the branch point of the front manifold is opened and closed on the downstream side, the water pipe valve is switched from the closed state to the open state, and the operation can be detected with high accuracy. In one embodiment of the apparatus, the cross-sectional culturing apparatus of the crystallization culturing apparatus of the single crystal culturing apparatus of the present embodiment is generally a body, and has a cylindrical main chamber 1 having a small diameter and a long length, and a crucible is disposed in the portion. 3. The quartz crucible on the inner side of the crucible 3 crucible is -9-200844270, and the graphite crucible is fitted to the outside of the crucible. The crucible 3 is supported on a support shaft (not shown) called a pedestal, and is hoisted in the circumferential direction while rotating in the circumferential direction in accordance with the rotation drive and the elevation drive of the support shaft. On the outer side of the crucible 3, the impedance heating type heater 4 is arranged concentrically so as to surround the crucible 3, and on the outer side thereof, the heat insulating tube 5 is disposed along the inner surface of the main chamber 1. . The heater 4 melts the polycrystalline crucible filled in the crucible 3, whereby the crucible 6 is accumulated in the crucible 3, and on the one hand, the upper crucible is used as the upper pull shaft. The line 7 is suspended by the center portion of the pull-up chamber 2. The wire 7 is driven up and down in the axial direction while being rotationally driven by the upper pull-up mechanism provided in the pull-up chamber 2. At the lower end of the line 7, a seed crystal holder for holding the seed crystal is mounted. The seed crystal held in the seed crystal holder is immersed in the melt 6 in the crucible 3, and the seed crystal is rotated while being slowly raised to drive the wire 7 below the seed crystal. The single crystal 8 is gradually growing. Further, above the crucible 3, a substantially cylindrical heat shield 9 is provided in a concentric shape close to the melt 6 in the crucible 3 so as to surround the periphery of the single crystal 8. This heat shielding body 9 is made of graphite and serves as a task for blocking the radiant heat from the melt 6 or the heater 4 in the crucible 3. In order to effectively exhibit the heat shielding effect, the heat shielding body 9 is gradually enlarged in diameter from the lower side, and the lower portion is inserted into the crucible 3 so as to be positioned above the melt 6 in the crucible 3. The inverse truncated cone shape (conical shape) is ideal. -10- 200844270 On the inner side of the heat shielding body 9, a substantially cylindrical cooling body 10 is arranged concentrically. The cooling body 10 is made of a copper-based metal having good thermal conductivity, and a water passage through which cooling water flows is formed inside. In the cooling body 1 〇, the water supply pipe 14 is connected to the inlet of the water passage, and the drain pipe 15 is connected to the outlet of the water passage. The water supply pipe 14 and the drain pipe 15 are also made of a copper-based metal. The cooling body 10 passes through the water supply pipe 14 and flows into the cooling water. The cooled cooling water flows out of the cooling body 1 through the water passage, and is discharged through the drain pipe 15. Thus, the cooling body 1 is forcedly cooled by the cooling water flowing inside. The heat sink 10 is disposed in the lower portion of the heat shield 9, and particularly serves to accelerate the cooling of the high temperature portion by particularly surrounding the high temperature portion after solidification of the single crystal 8. Further, in the same manner as the heat shield 9, the heat sink body 1 has a tapered shape in which the diameter is gradually increased from the lower side toward the upper side. The water supply pipe 14 and the drain pipe 15 are welded to the cooling body 10 in a state where no load is applied to the cooling body 10, and a plurality of support arms 1 are radially arranged around the pull-up shaft in the furnace body. 3 is supported in the furnace. The support arm 13 is composed of a bar-shaped material which is horizontally extended from the upper inner surface of the main chamber 1 toward the center of the furnace body and which is bent downward from the middle, and the cooling body 10 is used. The upper edge portion is detachably coupled to each of the tip end portions of the respective support arms 13 by bolts or the like. Each of the support arms 13 is made of stainless steel, and the cooling body 10 is forcibly cooled by water passing through another system. Further, in the main chamber 1, a vacuum exhaust pipe 11 connected to a vacuum pump -11 - 200844270 (not shown) is connected. By the driving of the vacuum pump, the internal air of the furnace body is exhausted through the vacuum exhaust pipe 11, and the furnace body is used as a decompression atmosphere. In the path of the vacuum exhaust pipe 11, a butterfly valve (not shown) is provided, and the pressure in the furnace body is adjusted by the degree of opening and closing of the butterfly valve. The butterfly valve is driven by an instruction from the control unit 22 shown in Fig. 3 which will be described later. " In the upper portion of the pull-up chamber 2, a purge gas introduced into the furnace body, such as an inert gas such as Ar gas, is introduced into the tube I. In the furnace body, an inert gas is supplied through a flushing gas introduction pipe, and the inside of the furnace is used as an inert gas atmosphere under reduced pressure. The amount of inert gas introduced into the furnace is adjusted by a mass flow controller provided in the path of the flushing gas introduction pipe. The mass flow controller is driven by an instruction from the control unit 22 shown in Fig. 3 which will be described later. In the main chamber 1, a pressure gauge 12 for detecting the internal pressure of the furnace body is provided. However, the detection of the pressure in the furnace is not limited thereto, and it is also preferable that the pressure in the furnace can be substantially detected. For example, it is also preferable to detect the gas φ pressure outside the furnace. Figure 3 is a system diagram of a water leakage monitoring system in a single crystal growth apparatus. As shown in Fig. 3, the first flow meter 17 and the automatic first opening and closing valve 19 are provided in the water supply pipe 14 in the path. The first flow meter 17 detects the flow rate of the cooling water flowing into the cooling body 10 through the water supply pipe 14. As the first flowmeter, it is possible to apply an ultrasonic type. The first opening and closing valve 19 opens the path of the water supply pipe 14 in the open state, and blocks the path of the water supply pipe 14 in the closed state. Here, the first flowmeter 17 is provided in the first flowmeter in the case where the length of the pipe is 3 m or less from the cooling body 10, and the first -12-200844270 on-off valve 19 is provided in the first flowmeter. 1 7 on the upstream side. In the upstream area of the water supply pipe 14, a water supply pump (not shown) that sends cooling water is disposed. Similarly, in the drain pipe 15, a second flow meter 18 and an automatic second on-off valve 20 are provided in the path. The second flow meter 18 detects the flow rate of the cooling water flowing out of the cooling body 10 through the drain pipe 15. As the second flow meter 18, an ultrasonic type can be applied. The second on-off valve 20 opens the path of the drain pipe 15 in the open state, and blocks the path of the drain pipe 15 in the closed state. Here, the second flow meter 18 is provided in the lower flow side of the second flow meter 18 from the viewpoint of the length of the pipe, within 3 m from the cooling body 1 . Further, in the drain pipe 15, a branch pipe 16 which is branched from between the second flow meter 18 and the second opening/closing valve 20 is attached. In the branch pipe 16, a dedicated automatic third opening and closing valve 21 is provided in the path. The third on-off valve 21 opens the path of the branch pipe 16 in the open state, and blocks the path of the branch pipe 16 in the closed state. The downstream end of the manifold 16 is open to the outside of the furnace. The first flow meter 17 and the second flow meter 18 are connected to the control unit 22, and the control unit 22 receives the flow rates L1 and L2 individually detected by the first flow meter 1 7 and the second flow meter 1 8 . Signal. Further, the control unit 22 is connected to the pressure gauge 12, and the control unit 22 receives a signal about the pressure P in the furnace body detected by the pressure gauge 12. Then, the first on-off valve 19, the second on-off valve 20, and the third on-off valve 21 are operated by an instruction from the control unit 22. Next, an example of the crystal growth of such a single crystal growth apparatus will be described -13-200844270. In the crucible 3, 1 〇〇kg of polycrystalline ruthenium raw material was placed, and then the inside of the furnace was used as an Ar atmosphere of 200 Pa. The polycrystalline silicon material in the crucible 3 is melted by the heater 4 provided outside the canister 3, and the seed crystal of the orientation of 〇 〇 is used, and a single crystal having a diameter of 20 mm is grown below. At this time, the liquid level of the melt 6 in the crucible 3 is maintained at a constant level. As the crystal grows, the pan 3 is slowly raised. Further, the pan 3 is rotated in the same direction or in the opposite direction to the direction of rotation of the single crystal 8. In the normal operation, the first on-off valve 19 and the second on-off valve 20 are both in an open state, and the third on-off valve 21 is in a closed state. In this manner, the cooling water flows through the water supply pipe 14 and the drain pipe 15 of the opened path to the cooling body 10' to forcibly cool the cooling body 1 〇. Thereby, in particular, forced cooling is performed: a high temperature portion after solidification of the single crystal 8. As a result, the pull-up speed of the single crystal 8 can be 2 mm/min or more. Incidentally, the pull-up speed of about 1 mm/min is achieved without using the cooling body 10. Further, since the branch pipe 16 is blocked, the cooling water does not flow. Here, the operation of the water leakage monitoring system performed in the work will be described below. Fig. 4 is a flow chart showing the operation of the water leakage monitoring system of the single crystal growth apparatus. As shown in Fig. 4, first, in the step #5' control unit 2, the signal from the first flow meter 17 regarding the inflow flow rate L1 of the cooling water toward the cooling body 10 is received one by one, from the second flow meter 1 8 signal about the outflow flow rate L2 of the cooling water from the cooling body 1 and the pressure p from the pressure-14 - 200844270 force meter 12 about the furnace body. Next, in step #10, the control unit 22 sequentially calculates, among the received signals, a flow difference between the inflow flow rate L1 and the outflow flow rate L2 by the signal about the inflow flow rate L1 and the outflow flow rate L2 (= L1-L2). In conjunction with this, the pressure variation ΔΡ per unit time is successively calculated by the signal about the pressure P in the furnace. Next, at step #15, the control unit 22 successively compares the calculated flow difference ΔL with the threshold ΔΔ LB set in advance. The information on the threshold 値 Δ LB of the flow rate difference is stored in the memory mounted on the control unit 22. The threshold 値 Δ LB is ideally set in consideration of the detection accuracy of the first flow meter 17 and the second flow meter 18, and is set to 30 cc from the current measurement accuracy of the flow meter and the amount of cooling water. More than seconds is the best. In conjunction with this, successive comparisons are made: the calculated pressure variation ΔΡ and the previously set threshold 値ΔΡΒ. The information on the threshold 値ΔΡΒ of the pressure fluctuation is also stored in the memory mounted on the control unit 22. In the case where there is a pressure fluctuation of twice or more in the maximum fluctuation of the pressure in the furnace during the normal operation without leaking from the cooling body, the threshold 値 Δ PB is set to be the most abnormal, and the threshold 値 Δ pB is set to the maximum. good. At step #2 0, it is successively determined whether the flow difference Δ L exceeds the threshold △ Δ LB. When water leakage occurs in the cooling body 10, since the water leakage amount appears as a flow difference ΔL, it is possible to temporarily determine whether or not there is water leakage by whether or not the flow rate difference ΔL exceeds the threshold 値Δ L B . When the flow rate difference ΔL has not exceeded the threshold 値Δ LB, it is determined that there is no water leakage and the process proceeds to step #25. On the other hand, if it exceeds, it is temporarily determined that there is a leak of -15-200844270 and enters. Step # 3 0. In step #25, it is determined whether or not the pressure fluctuation ΔP has exceeded the threshold 値 Δ PB. If water leakage occurs in the cooling body, the leak occurs in the furnace and the pressure in the furnace rises. This is caused by the pressure fluctuation ΔΡ. Therefore, is the pressure fluctuation ΔP exceeding the threshold? 8, and can temporarily determine whether there is water leakage. When the pressure fluctuation ΔP has not exceeded the threshold △ Δ PB, it is determined that there is no water leakage and the process proceeds to step #5. On the other hand, if it exceeds, it is determined that there is a water leakage and the process proceeds to step #35. When it is determined in step #20 that there is a water leakage, in step #30, in a specific period in which the flow rate difference Δ L exceeds the threshold 値 Δ LB as a starting point, it is sequentially determined whether or not the pressure fluctuation Δ P exceeds the threshold 値 Δ PB. That is, when the flow difference Δ L exceeds the threshold 値 Δ LB, it is determined whether or not the pressure change Δ P exceeds the threshold 値 Δ PB. From the viewpoint of reducing the influence of the sudden noise output to the flowmeter, the optimum period is preferably 1 second or longer, and is set to 5 from the viewpoint of reducing the damage of the water leakage from the cooling body. Within seconds is the best. In the case where the flow rate difference and the pressure fluctuation Δ 大 are more than the threshold 値 Δ LB and Δ PB, the two phenomena which are caused by the difference in water leakage appear in the time-time simultaneously. The system can judge the water leakage with high precision. If it is determined that there is a water leakage at step #30, the process proceeds to step #40 and an appropriate safety treatment is taken. On the other hand, in the case where the flow rate difference ΔL and the pressure fluctuation ΔP are not more than the threshold 値 Δ LB and Δ PB at the same time, it is caused by the timing of the time interval -16-200844270. There are two different phenomena of water leakage. Therefore, in this case, there is actually no water leakage. It is conceivable that the flow difference ΔL and the pressure variation Δ P are erroneously detected, and it is possible to judge that there is no water leakage with high accuracy. If it is judged that there is no water leakage at step #3 0, the process returns to step #5 and the monitoring is continued. Further, in the case where it is determined in step #25 that there is a water leakage, in step #3 5, in a specific period in which the pressure fluctuation Δ P exceeds the threshold 値 Δ PB as a starting point, it is preferable to successively determine within one second: Whether the flow difference Δ L exceeds the threshold 値ALB. That is, when the pressure fluctuation ΔΡ exceeds the threshold 値ΔPB, it is determined whether or not the flow rate difference ΔL also exceeds the threshold Δ Δ LB. When the pressure fluctuation ΔΡ and the flow rate difference AL are substantially simultaneously exceeding the thresholds △ Δ PB and Δ LB, as in the case of step #3〇, it is possible to judge the water leakage with high accuracy. In the case where it is judged that there is a water leakage at step #35, the process proceeds to step #40 and an appropriate safety treatment is taken. On the other hand, in the case where the pressure fluctuation ΔΡ and the flow rate difference AL do not exceed the thresholds 値 Δ PB and Δ LB at the same time, as in the case of step #30, it is possible to judge that there is no water leakage with high accuracy. In the case where it is judged that there is no water leakage at the step #3 5, the process returns to the step #5 and the monitoring is continued. At step #40, it may be a safe disposal as below. The first 'control unit 22 sends a command to the first on-off valve 19, the second on-off valve 20, and the third on-off valve 21, and switches the first on-off valve 19 and the second on-off valve 20 from the open state to the closed state. The third opening/closing valve 2 1 is closed in the open state Sg (the third picture of the dream). If so, -17- 200844270 is blocked because the path of the water supply pipe 14 and the drain pipe 15 is blocked, so the water supply system to the cooling body 10 is forcibly stopped. In conjunction with this, the cooling water remaining in the cooling body 10 is discharged to the outside through the branch pipe 16 which has been opened. Here, the cooling water that has stopped flowing inside the cooling body 1 被 is heated by the influence of the high temperature in the furnace body, and is heated and heated to be violently heated, thereby causing volume expansion and high pressure, so that it is opened. The outer tube 16 is discharged to the outside. Therefore, it is possible to prevent the explosion of water vapor due to leakage and prevent it from becoming safe. Secondly, it is reported from the cooling body 1 that there is a water leakage, by the issuance of a warning sound or the turning on of the warning light. Thus, it can be recognized that water leakage has occurred in the cooling body 10. Third, the energization to the heater 4 is stopped. In conjunction with this, the rotation and lifting of the wire 7 on which the single crystal 8 is suspended are stopped while the rotation and lifting of the crucible 3 in which the melted liquid 6 is stored are stopped. In such a single crystal growth apparatus, an example of the processing based on the detection enthalpy from the first flowmeter 1 7 , the second flowmeter 1 8 , and the pressure gauge 12 is shown in Table 1 below. -18- 200844270
流量差閾値ALB [cc/秒] 壓力變動閾値ΔΡΒ [MPa/秒〕 0.00013 流量差AL 〔⑶/秒〕 60 60 壓力變動ΔΡ [MPa/秒〕 產生時期 判斷有無漏水 0.00005 不問 無漏水 0.00020 非同時 無漏水 0.00020 同時 有漏水 在此’將案例1〜3作爲丨例而表示。在任一案例，都 是將對流量差Δ L的閾値△ LB作爲5〇cc/秒、將對壓力 變動△ P的閾値△ P B作爲〇 . 〇 〇 0 1 3 Μ P a。 在案例1 ’流里差△ L爲6 0 c c /秒，超過閾値△ [ b。 壓力變動△ P爲〇.〇〇〇〇5MPa ’爲閾値△ pb以內。在此情 況’不問流量差△ L與壓力變動△ p的產生時期，被判斷 爲沒有漏水。 在案例2，流量差△ L爲60cc/秒，超過閾値△ lb。 壓力變動ΔΡ爲0.00020MPa，此亦超過閾値αρβ。但是， 流量差△ L與壓力變動△ P的產生時期並非同時，空開特 定期間以上。在此情況，被判斷爲沒有漏水。 在案例3，係與案例2相同，流量差△ L爲6 〇 c c ^/秒 ，超過閾値△ L B，壓力變動△ p爲〇 · 〇 〇 〇 2 〇 μ P a，超過闆 値ΔΡΒ。但是，流量差AL與壓力變動ΔΡ的產生時期爲 同時。在此情況，被判斷爲有漏水。 -19- 200844270 如此，在本實施形態的單晶育成裝置，係根據流量差 △ L及壓力變動△ P就能判斷來自冷卻體的冷卻水漏水’ 而因爲流量差△ L、壓力變動△ P係個別起因於漏水之完 全不同的現象，根據兩者之漏水判斷係精確度高。因此， 可以高精確度檢測來自冷卻體的漏水，可進行安定的作業 〇 在本發明的單晶育成裝置，係可在高精確度檢測來自 冷卻體的漏水，安定作業性優良。因此，本發明，係在使 用冷卻體而謀求上拉速度的高速化之單晶育成裝置，爲非 常有用。 【圖式簡單說明】 第1圖係表示爲本發明的一實施形態的單晶育成裝置 的構成之縱剖面圖。 第2圖爲第1圖的單晶育成裝置之橫剖面圖。 弟3圖爲漏水監視系統之系統圖。 桌4圖爲表不漏水監視系統的動作之流程圖。 【主要元件符號說明】 L1 :流入流量 L2 :流出流量 P :壓力 1 :主室 2 :上拉室 20- 200844270 坩鍋 加熱器 保溫筒 融液 線 單晶 熱遮蔽體 :冷卻體 :真空排氣管 :壓力計 z支持臂 :給水管 z排水管 =分歧管 :第1流量計 :第2流量計 :第1開閉閥 :第2開閉閥 :第3開閉閥 :控制部Flow difference threshold 値ALB [cc/sec] Pressure variation threshold 値ΔΡΒ [MPa/sec] 0.00013 Flow difference AL [(3)/sec] 60 60 Pressure variation ΔΡ [MPa/sec] Judgment period for water leakage 0.00005 No water leakage 0.00020 No simultaneous Leakage 0.00020 At the same time, there is water leakage. Here, Cases 1 to 3 are shown as examples. In either case, the threshold 値 Δ LB for the flow difference Δ L is taken as 5 〇 cc / sec, and the threshold 値 Δ P B for the pressure variation Δ P is taken as 〇 〇 〇 0 1 3 Μ P a . In the case 1 'flow difference Δ L is 6 0 c c / sec, exceeding the threshold 値 △ [ b. The pressure variation ΔP is 〇.〇〇〇〇5MPa ’ is within the threshold 値Δpb. In this case, it is judged that there is no water leakage regardless of the generation period of the flow difference ΔL and the pressure fluctuation Δp. In Case 2, the flow difference ΔL is 60 cc/sec, which exceeds the threshold 値 Δ lb. The pressure variation ΔΡ is 0.00020 MPa, which also exceeds the threshold 値αρβ. However, the flow rate difference Δ L and the pressure fluctuation Δ P are not generated at the same time, and are more than a certain period of time. In this case, it is judged that there is no water leakage. In Case 3, the same as Case 2, the flow difference ΔL is 6 〇 c c ^/sec, exceeding the threshold 値 Δ L B , and the pressure variation Δ p is 〇 · 〇 〇 〇 2 〇 μ P a, exceeding the plate 値ΔΡΒ. However, the flow rate difference AL and the pressure fluctuation ΔΡ are generated simultaneously. In this case, it is judged that there is a leak. -19- 200844270 In the single crystal growth apparatus of the present embodiment, the cooling water leakage from the cooling body can be determined based on the flow rate difference ΔL and the pressure fluctuation ΔP, and the flow rate difference ΔL and the pressure fluctuation Δ P are Individually due to the completely different phenomenon of water leakage, the accuracy of the water leakage is high. Therefore, the water leakage from the cooling body can be detected with high accuracy, and the operation can be performed stably. 〇 In the single crystal growth apparatus of the present invention, water leakage from the cooling body can be detected with high accuracy, and the workability is excellent. Therefore, the present invention is very useful in a single crystal growth apparatus which uses a cooling body to increase the speed of the pulling up. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a longitudinal sectional view showing a configuration of a single crystal growth apparatus according to an embodiment of the present invention. Fig. 2 is a cross-sectional view showing the single crystal growth apparatus of Fig. 1. Brother 3 shows the system diagram of the water leakage monitoring system. Table 4 is a flow chart showing the operation of the watertight monitoring system. [Main component symbol description] L1: Inflow flow rate L2: Outflow flow rate P: Pressure 1: Main chamber 2: Pull-up chamber 20- 200844270 Shabu-shabu heater insulation tube Melt line Single crystal heat shield: Cooling body: Vacuum exhaust Tube: pressure gauge z support arm: water supply pipe z drain pipe = branch pipe: first flow meter: second flow meter: first open/close valve: second open/close valve: third open/close valve: control unit