200417524 (1) 玖、發明說明 【發明所屬之技術領域】 本發明是關於一種在半導體製程所使用的矽玻璃 ，更具體而言，關於一種表面具細凹凸之同時對於輕 層鈾刻較小表面狀態變化的矽玻璃工模及其製造方法 【先前技術】 矽玻璃工模是在製造半導體元件的擴散工程，氣 長工程，蝕刻去灰工程等各種工程被使用。該矽玻璃 的表面是施以稱爲噴砂或硏削加工的處理而精修加工 凸的不透明者，或是以稱爲鏡面硏磨或淬火精修加工 炎硏磨等而精修加工成平滑又透明者等，依用途等被 地選擇，惟大都使用者具有洗淨等容易又不容易弄髒 有精修精修加工成透明表面的工模。其中，在擴散工 氣相成長工程中，特別是在氣相成長工程中以 (Chemical Vapor Deposition ) 法等在半導體元件成 聚矽膜’惟這時候在精修加工成透明的矽玻璃工模也 矽膜堆積作爲副生成物，而該副生成物被剝離成爲微 生污染半導體元件。因此，須定期地除去副生成物。 該除去使用含有氫氟酸及硝酸的溶液，惟平滑工模的 也同時地被蝕刻使得表面變粗，產生表面積等的表面 變化’急速地變動副生成物的附著量，而消耗的氣相 氣體的消耗量也變動，有難以控制對於半導體元件的 膜的成長量的缺點問題。如此，在工模表面以噴砂加 工模 微表 相成 工模 成凹 的火 適當 而具 程， CVD 長如 有聚 粒產 一般 表面 狀態 反應 聚矽 工形 -5- (2) (2)200417524 成微細凹凸，而在此積極地捕捉副生成物以謀求防止發生 微粒，惟這一次是從加工微細凹凸的時所發生的加工塑性 層或微破裂等損傷部分在使用時有矽玻璃的微細破片飛散 而會發生污染半導體元件的微粒。又，若副生成物變厚， 則發生依矽玻璃與聚矽之熱脹相差的損壞，爲了防止該情 形，在使用工模之前進行依氣體蝕刻或濕蝕刻的洗淨，惟 與具有透明表面的工模的情形同樣地必須定期地除去副生 成物，有微細凹凸面同時地被蝕刻而使表面狀態變化的缺 點問題。 上述缺點問題是不僅在對於半導體元件的擴散或氣相 成長工程，而對於蝕刻處理也同樣，亦即，在一面流動處 理氣體一面利用電漿等進行蝕刻或去灰工程，也有副生成 物堆積在矽玻璃經剝離而發生微粒的情形，與CVD等同 樣地依噴砂或硏削加工而在表面形成微細凹凸，積極地捕 捉副生成物以謀求防止發生微粒。但是，從加工凹凸時所 發生的加工塑性層或微破裂等的損傷部分，在使用時藉由 電漿有矽玻璃的微細破片會飛散，而成爲污染半導體元件 的微粒等缺點問題。特別是在乾蝕刻中，矽玻璃工具的表 面也被施以與含有氫氟酸溶液處理類似的蝕刻，使得表面 狀態變化較大，有很難控制半導體元件的蝕刻處理本身等 缺點問題。 爲了解決上述缺點問題，提案一種以含有氟化氫溶液 蝕刻經機械加工的工模而開放微破裂，並作成開放微破裂 之面的矽玻璃工模（日本特開平10-59744號公報），或 (3) (3)200417524 是提案一種以機械加工矽玻璃工模表面作成凹凸之後，以 含有氟化氫與氟化錢的溶液加以處理，在表面形成20至 3 00 μηι的窪下狀凹部與間隔20至30 μηι，寬度0.5至50 μηι的槽溝’且在槽溝間及槽溝內均勻地分散寬度1至5 〇 μιη ’高度0.1至10 μηα的小突起的矽玻璃工模（日本特 開平2002- 1 04 843號公報）。然而，在實際使用時，上述 工模是藉由使用使凹部均變成大硏钵狀，而有副生成物的 附著量急變，或減少凹凸，並某一程度地繼續使用，則有 發生剝離微粒等缺點。 鑑於此種現狀，本案發明人等經無心硏究的結果，發 現了將矽玻璃工模的表面粗糙度以中心線平均粗糙度Ra 作成〇·1至20 μιη，且對於輕微的表層蝕刻處理也作成表 面狀態變化較小的面，就可避免副生成物的剝離或矽玻璃 的微細破片的飛散，且減少處理氣體的消耗變化而成爲容 易控制各工程的處理。又，也發現了上述矽玻璃工模交互 重複複數次特定的物理式表層除去手段與特定的化學式表 層除去手段，就可容易的製造’而完成本發明者。 亦即，本發明的目的是在於提供一種在使用時不會發 生污染半導體元件的微粒，且即使重複使用也不會變動處 理條件的矽玻璃工模。 又，本發明的目的是在於提供一種矽玻璃工模的製造 方法。 【發明內容】 -7- (4) 200417524 本發明的一種矽玻璃工模及其製造方法 導體的工程所使的矽玻璃工模，其特徵爲： 部分或全部存在中心平均粗糙度Ra爲0 · 1 ： 凸，且對於輕微的表層蝕刻處理，表面狀態 本發明的矽玻璃工模是如爐芯管，晶圓 蝕刻，去灰用腔等，製造半導體元件的工程 ;在其表面的一部分或全部存在中心線平均 0.1至20 μηι的凹凸，且對於輕微的表層蝕 狀態的變化小的工模。上述表面狀態的變 3.0至4.0%而液溫爲17至23 t：的氫氟酸 1 5至1 7小時者，及使用觸針部前端的R爲 圍的觸針型表面粗糙度測定裝置來測定依據 表面的 JI S B 0 6 0 1的中心線平均粗糙度，而 均粗糙度的變化率作成5 0%以下較理想。亦 刻，例如依電漿氣體的蝕刻會使矽玻璃工模 ，惟具體而言，在初期階段Ra會變大，惟 與表示上述表面狀態的變化小的中心線平均 率有關連，若該變化率爲50%以下，則在實 變化仍較小。上述氫氟酸溶液的濃度在未滿 變化會過度費時而效率較低，若超過上述範 化速度變快而判定時間雖變短，惟從溶液取 用水來置換表面一直到停止飽刻爲產生誤差 溶液的溫度1 7至23 °C，是其溫度爲一般性 又，蝕刻處理時間1 5至1 7小時，是爲 ，屬於製造半 在其表面的一 g 2 0 μ m的凹 的變化小。 載置用晶舟， 所使用的工模 粗糙度Ra爲 刻處理，表面 化小是以濃度 溶液蝕刻處理 2至1 〇 μ m範 與蝕刻前的該 將該中心線平 即，實際的蝕 的表面有變化 其變化大小是 粗糙度的變化 使用上Ra的 上述範圍，則 圍，則初期變 出測定物，使 。又，氫氟酸 :而被採用。 了得到判定所 (5) (5)200417524 用的高精度的變化率所需的時間。在上述變化率的測定爲 使用依據J I s B 0 6 0 1的觸針部前端的R爲2至1 0 μιη的觸 針型表面測定裝置的理由，是在實際使用時的矽玻璃工模 的表面狀態變化，因存在於該初期狀態面的微破裂會因蝕 刻處理而擴大，或是因其表面的鋸齒凹凸被蝕刻處理而產 生形狀變化而會變大。在使用例如雷射的反射光的測定裝 置的非接觸型的測定裝置來測定，則從測定形狀所算出的 中心線平均粗糙度爲正確者，惟也檢測在使用中因副生成 物立即會被塡滿的窄小谷部等，而在使用時難以瞭解處理 條件變化所產生的較大的狀態變化。使用該觸針型表面側 定裝置的測定法，則當然凸部的變化會容易測出，特別是 也容易測出在副生成物的附著狀況敏感的谷部變化。上述 觸針部尖端的R爲2至1 0 μιη，乃爲了作成從未檢測細小 谷的範圍的2 μιη，至可判定實質上凹凸的1 〇 μιη的範圍 者，而可容易地測定適應於實際使用時的表面狀態的變化 〇 在實際使用矽玻璃工模中，有對應於使用過程的副生 成物的適當捕捉量，例如在C V D過程時，晶圓上的膜成 長的多餘氣體，而在依電漿等的乾蝕刻工程時，被蝕刻的 反應氣體，會使矽玻璃工模的表面變粗糙，成爲作爲更多 副生成物而捕捉堆積在工模上。若副生成物的堆積量過多 ，則將膜形成在晶圓上的氣體減少至需要以上而妨礙膜的 成長或蝕刻。另一方面，若捕捉較少，則因剝離等而發生 微粒，又，在依使用時的矽玻璃工模的粗糙度或狀態，會 -9- (6) (6)200417524 從初期狀態變化而有與上述同樣的缺點問題。矽玻璃工模 的表面凹凸是，排列著鋸狀凹凸或不規則地連續銳角山谷 的鋸齒或台形狀的凸部者，惟因在實際使用時的蝕刻處理 使緣部成爲尖細的大碗狀凹凸，而從副生成物的捕捉能力 等初期狀態變化較大。又，從初期狀態形成碗狀凹凸時， 則表面積較小之故，因而副生成物的捕捉能力無法耐於實 用，又該碗狀緣部尖細部分脫落，會發生微粒。所以’本 發明的矽玻璃工模，在其表面一部分或是全部存有中心線 平均粗糙度Ra爲0.1至20 μιη的凹凸。因存有該凹凸’ 可確實地捕捉副生成物而可抑制剝離。較理想是將上述凹 凸作爲形成大凹凸與在其表面形成微細的淺碗狀凹部的多 重構造較佳。具有該多重構造，藉由在輕微鈾刻不容易變 化的大波形凹凸可確保能捕捉所需厚度的副生成物的凹凸 〇 又，在該大波狀凹凸存在微細的淺碗狀凹凸，就可得 到具有固定不會剝離經捕捉的副生成物，且安定表面的工 模。特別期望是淺碗狀凹部比凹部緣徑其底深度還小’且 相鄰的凹部間的境界緣部並不是銳角的凸者。由此，即使 凹部在使用時被鈾刻，緣部附近也均等地減損，可防止在 與相鄰的凹部之間發生以銳角容易脫落的突起狀倒角。 本發明的矽玻璃工模，是在矽玻璃表面交互地重複適 用兩次以上依物理式表層除去手段與化學式表層除去手段 就可製造。較理想是選擇以物理式表層除去手段所形成的 表面粗糙度依次變小的處理條件較佳。 -10- (7) 200417524 依固定砥粒 游離砥粒的 。又，作 砥石等，作 硏磨的處理 在物理式表 性層或微破 飛散，而成 不均質侵蝕 槽溝，而使 或蝕刻工程 手段之後適 層成開放微 的變動，惟 無法充分地 欲充分地進 破裂的損壞 凹部且外周 飛散微細玻 凹部有上述 法充分地除 或微破裂等 變大。又， 尖細凹部， 上述物 處理，依游 依液體硏磨 砥石，具體 有二氧化矽 砥粒分散並 中，使用在 的工模時， 生源。還有 不完全的微 化較大，產 。但是，繼 層除去手段 發生微粒之 層除去手段 工塑性層或 表層手段所 則產生很多 。特別是從 作爲上述外 所記載的處 表層除去手 使得蝕刻處 用時的蝕刻 理式表層除 離砥粒的硏 的處理或是 而言有樹脂 ，或 SiC ， 噴上於液體 矽玻璃表面 有矽玻璃的 在蝕刻處理 破裂的開放 生必須變動 續上述物理 ，除了可除 外，還可減 的表層除去 開放微破裂 形成的加工 大槽溝或碗 外周緣的尖 周緣也不會 理法，惟在 段所形成的 理時的表面 ，則出現多 去手段是指 磨處理，依 這些的組合 接合型鑽石 作爲依液體 的處理等。 形成加工塑 微細破片會 工程時產生 所產生的深 CVD工程 式表層除去 去加工塑性 少表面狀態 量較少，則 。如此，若 塑性層或微 狀或硏缽狀 細部分容易 發生尖細的 該方法中無 加工塑性層 狀態的變化 數外周緣的 砥石的硏削 噴砂處理， 爲固定砥粒 爲游離砥粒 ，有將游離 層除去手段 裂等損傷層 爲微粒的發 ，會產生依 表面狀態變 等處理條件 當化學式表 破裂而減少 依化學式表 進行除去加 行以物理式 層的除去， 緣尖細凹部 璃的破片。 專利文獻2 去以物理式 的損壞層， 進行實際使 而容易發生 -11 - (8) (8)200417524 微粒。 本發明的製造方法，是在最初的物理式表層除去手段 之後依化學式表層除去手段形成在表面具有微破裂被開放 的表面，例如形成具多數硏缽或碗狀凹凸的表面之後，再 適用物理式表層除去手段，將凹凸的銳角部分作成波狀， 又藉由適用化學式表層除去手段，形成殘留在較平坦面的 加工塑性層或開放稍微留下的微破裂者。上述物理式表層 除去手段及化學式表層除去手段是交互地重複地適用兩次 以上較佳。由此得到使用中的矽玻璃工模的表面狀態變化 較小的工模。上述物理式表層除去手段是較理想是表面粗 糙度比最初還小般地選擇下一物理式表層除去手段較佳。 在由此所形成的大波狀的凹凸形狀不會大變化的範圍內， 僅將下一物理式表層除去手段的損壞或微破裂，不但以下 一化學式表層除去手段可容易地開放，還在大波狀凹凸的 表面可作成具有多數碗狀凹部的多重構造。例如最初使用 粒度較大的砥粒，而在下一除去手段使用粒度較小的砥粒 等。這時候，也可採用組合液固定砥粒砥石的硏削處理之 後依游離砥粒的硏磨處理等的物理式表層除去手段的組合 。例如最初使用含有# 1 20的鑽石砥粒的固定砥粒砥石之 後，適用依#600的SiC游離砥粒的噴砂處理等。 作爲在本發明所使用的化學式表層除去手段，有依含 有氟化氫的溶液的處理，惟較理想爲在最後的物理式表層 除去手段後的化學式表層除去手段，在上述溶液再含有氟 化銨較佳。由此，對於情節並不明確，惟被除去如依化學 -12· (9) 200417524 式表層除去手段所形成的碗狀或產生硏缽狀 部的尖細突起或其他的銳角突起而可作成半 此乃可能爲氧化氫與氟化錢及砂玻璃所反應 例如良好地發生在碗狀底部，而不會發生在 突起部的結晶會立即脫離，結果，突起部被 除去，而成爲未具有銳角部分的具圓形的形 地，在上述含有氟化氫的溶液分散粒徑1 〇 3 脂，二氧化矽或陶瓷的任一或其組合的微粒 該微粒子就可容易除去工模表面的損壞層， 形成能變高，而可簡化製造順序。又附加超 拌手段就可得到處理的更效率化。 本發明的矽玻璃工模，是在其使用時可 之外，即使重複使用也幾乎不會變動處理條 安定地高品質的半導體元件的處理的效果。 璃工模是藉由可重複適用二次以上特定的物 手段與化學式表層除去手段而能容易地製造 値較高者。 【實施方式】 以下說明本發明的實施例，惟由此本發 限定者。又，以下的實施例1及比較例1的 糙度Ra是藉由表面粗糙度計（日本東京精 的 Surfcom 3 00B) 所測定。此以外的實施 三豊（股）所製的表面粗糙度計（SJ-400) 凹部的外周緣 滑的凹凸面。 產生的結晶， 突起部惟吸收 選擇性地鈾刻 態者，更具體 E 2 0 0 μ m的樹 子較佳。分散 且微細凹凸的 音波振動或攪 減少發生微粒 件，而可發揮 而且上述矽玻 理式表層除去 ，其工業上價 明是並未加以 中心線平均粗 密（股）所製 例等使用日本 -13- (10) (10)200417524 實施例1 以含有#3 00的鑽石砥粒的樹脂接合砥石硏削直徑3〇〇 mm的石英玻璃表面來製作圓板狀乾蝕刻用工模。所得到 工t旲的中心線平均粗f造度R a是1 . 2 μ m。將該工模浸漬1 0 分鐘在5 0 %的氫氟酸溶液。所得到的工模的中心線平均粗 糙度Ra是2。8 μιη。之後以# 1 000的SiC砥粒的樹脂接合 砥石進行表面除去該工模，將中心線平均粗糙度Ra作成 0.5 μ m，又以氟化氫1 5質量％，氟化銨1 5質量％，醋酸 5 0質量％及水所構成的處理液處理一小時。這時的中心線 平均粗糙度Ra是1 ·4 μπι。將上述工模浸漬於20 °C，3 .5 質量％的氫氟酸溶液來調查R a的變化，則如表1所示。 將上述0小時時以顯微鏡所觀察的表面照片表示於第1圖 ’而將餓刻處理1 6小時後以顯微鏡所觀察的表面照片表 不於第2圖。又，將0小時時的掃描電子顯微鏡觀察的照 片表示於第3圖。 比較例1 以含有#3 00的鑽石砥粒的樹脂接合砥石硏削與實施 例1同樣的石英玻璃工模來製作圓板狀乾蝕刻用工模。所 得到的工模的中心線平均粗糙度Ra是1 ·2 μπι。將該工模 浸漬10分鐘在10%的氫氟酸溶液。這時的Ra是1·3 μηι 。對於該工模與實施例1同樣地調查依3 . 5質量％的氫氟 酸的表面粗糙度的變化，則如表1所示。 (11) (11)200417524 表1 0時間 4時間 8時間 1 6時間 實施例1 Ra 1.4 μιχι 1.8 μ m 1.9 μιη 1.9 μηι 變化率 0% 2 9% 3 6% 3 6% 比較例1 Ra 1.3 μιη 1.9 μπι 2.8 μιη 3.3 μηι 變化率 0% 4 6% 1 1 5 % 1 3 0 % 由上述表1所知，實施例1的本發明的矽玻璃工模是 在3 · 5質量％的氫氟酸溶液的蝕刻測試中，R a等的表面狀 態的變化比比較例1極小。將依實施例1與比較例1的工 模，實際上投入在CF4/Ar氣體，2kw的電漿乾蝕刻裝置 ，實施例1的工模中進行5整批的處理，則微粒的發生數 是任一整批均不足1 0個。對於此，在比較例1的工模中 ，則在第3整批發生5 0個以上的大量微粒，而中止使用 。又，各使用後的Ra是實施例1的工模爲2 μιη，比較例 1的工模爲5.2 μιη，與依3 . 5質量％的氫氟酸溶液的蝕刻 測試同樣地有很大差異。又，比較實施例1的第5整批及 比較例1的第3整批的處理晶圓的蝕刻率，則比較例1的 工模對於實施例i的工模是蝕刻率較少。 實施例2 製作對應於直徑1 5 0 mm的矽晶圓的縱型氣相成長用 晶舟。將上述晶舟以#150 SiC砥粒進行噴砂處理，之後以 -15- (12) (12)200417524 15%氫氟酸溶液處理20分鐘後，再以#600 SiC砥粒進行 噴砂處理，然後，以氟化氫1 4質量％，氟化銨1 2質量％ 及水所構成的處理液處理 1小時。以掃描電子顯微鏡 (SEM)攝影所得到的晶舟表面。將其結果表示於第4，5 圖。該晶舟表面的粗糙度是中心線平均粗糙度Ra爲2 . 1 μπι。如第4，5圖所示地在大波狀凹凸的表面形成有淺凹 部的多重構造。將上述晶舟以20 t，3.5%氫氟酸溶液進 行1 6小時的蝕刻測試。將SEM攝影測試後的晶舟的表面 的照片表示於第6，7圖。形成大波狀凹部比先前稍寬廣 而減少數量的多重構造。這時的Ra是2.1 μιη。又，將上 述晶舟使用在實際的SiC的氣相成長工程，來堆積2 μπι 的膜。在上述成長工程的一積單成長，以4%氫氟酸溶液 重複5次/小時的洗淨。使用後的表面的r a是2.5 μ m。 比較例2 在與實施例2同樣的晶舟，以# 1 5 0 S i C砥粒進行噴砂 處理，又，以# 6 0 0 S i C砥粒進行噴砂處理。之後，以1 〇 % 的氫氟酸溶液進行1小時的處理。以S EM攝影所得到的 晶舟表面。將其結果表示於第8，9圖。晶舟的粗糙度是 中心線平均粗糙度Ra爲2.2 μπι。對於該晶舟，與實施例 2同樣地以2 0 °C，3 · 5 %氫氟酸溶液進行1 6小時的蝕刻 測試。將以SEM攝影測試後的晶舟的表面的照片表示於 第1 0，1 1圖，惟與大凹狀緣部連續有銳角凹部的第6圖 的表面有很大差異，Ra是4.8 μιη。又，將上述晶舟使用 -16- (13) (13)200417524 在實際的Sic的氣相成長工程，在2 μιη膜的每一積算成 長，以4%氫氟酸溶液重複5次/小時的洗淨。使用後的表 面的R a是5 . 1 μ m。又，減少從第三次急激地成長於晶圓 上的膜厚，又，可看到增加處理晶圓上的微粒。 產業上的利用可能性 本發明的砂玻璃工模是在使用時不會發生污染半導體 元件的微粒，且即使重複使用也不會變動處理條件之數， 因而可有用地使用作爲爐芯管，晶圓載置用晶舟，蝕刻， 去灰用腔，環，板。 【圖式簡單說明】 第1圖是表示以顯微鏡觀察實施例的乾蝕刻用工模表 面的5 0 0倍的照片。 第2圖是表示將實施例1的乾蝕刻用工模表面浸漬 16小時在3.5質量％的氫氟酸後以顯微鏡觀察的5 00倍的 照片。 第3圖是表示以掃描電子顯微鏡觀察實施例1的乾蝕 刻用工模表面的5 00倍的照片。 第4圖是表示以掃描電子顯微鏡觀察實施例2的晶舟 2〇〇倍的照片。 第5圖是表示以掃描電子顯微鏡觀察實施例2的晶舟 1 000倍的照片。 第6圖是表示將實施例2的晶舟以3 · 5 %氫氟酸溶液 •17- (14) (14)200417524 進行1 6小時的蝕刻測試之後的以SEM所觀察的200倍的 照片。 第7圖是表示將實施例2的晶舟以3.5%氫氟酸溶液 進行1 6小時的蝕刻測試之後的以SEM所觀察的1 000倍 的照片。 第8圖是表示以SEM觀察比較例2的晶舟的200倍 的照片。 第9圖是表示以SEM觀察比較例2的晶舟的1 000倍 的照片。 第1 〇圖是表示將比較例2的晶舟以3 · 5 %氫氟酸溶液 進行1 6小時的鈾刻測試之後的SEM所觀察的200倍的照 片。 第1 1圖是表示將比較例2的晶舟以3.5%氫氟酸溶液 進行1 6小時的蝕刻測試之後的SEM所觀察的1 〇〇〇倍的 照片。200417524 (1) 发明 Description of the invention [Technical field to which the invention belongs] The present invention relates to a silica glass used in a semiconductor process, and more specifically, to a surface with fine unevenness and a small surface for light uranium engraving State-changed silica glass mold and its manufacturing method [Prior technology] The silica glass mold is used in various processes such as diffusion engineering, gas length engineering, etching and ashing engineering for manufacturing semiconductor components. The surface of this silica glass is opaque, which is finished by a process called sandblasting or honing, or is smooth and smooth by mirror honing, quenching, or honing. Those who are transparent are selected according to the purpose, etc., but most users have a mold which is easy to clean and not easily soiled. Among them, in the vapor phase growth process of the diffusion process, especially in the vapor phase growth process (Chemical Vapor Deposition) method, a polysilicon film is formed on the semiconductor element. However, at this time, it is also processed into a transparent silicon glass mold. The silicon film is deposited as a by-product, and the by-product is peeled into a micro-contaminated semiconductor device. Therefore, by-products must be removed regularly. This removal uses a solution containing hydrofluoric acid and nitric acid, but the smooth mold is also etched at the same time to make the surface thicker, causing surface changes such as surface area. 'The amount of adhesion of by-products is rapidly changed and consumed, The consumption amount also varies, and there is a problem that it is difficult to control the growth amount of the film of the semiconductor element. In this way, the surface of the mold is sandblasted and the surface of the mold is concave. The mold is concave and the process is appropriate. The CVD is long. If the particles are produced, the general surface state reacts to the silicon shape. -5- (2) (2) 200417524 It forms fine irregularities, and actively captures by-products here to prevent the occurrence of particles. However, this time from the damage of the plastic layer or micro-cracks that occur when the fine irregularities are processed, there are micro fragments of silica glass during use. The particles are scattered and contaminate the semiconductor element. In addition, if the by-products become thicker, damage caused by the difference in thermal expansion between silica glass and polysilicon will occur. In order to prevent this, cleaning by gas etching or wet etching is performed before using the mold, but with a transparent surface Similarly, in the case of a mold, by-products must be removed periodically, and there is a problem in that fine uneven surfaces are simultaneously etched to change the surface state. The above-mentioned disadvantages are not only in the diffusion or vapor growth process of semiconductor elements, but also in the etching process, that is, the etching or deashing process using plasma or the like is performed while flowing the processing gas, and by-products are also accumulated in the In the case where silica glass is exfoliated to generate particles, similar to CVD or the like, fine irregularities are formed on the surface by sandblasting or honing, and by-products are actively captured to prevent the generation of particles. However, the damaged parts such as the processed plastic layer and micro-cracks that occur during the processing of the irregularities are scattered by the use of the fine fragments of the silica glass in the plasma, and become defects such as particles that contaminate semiconductor devices. Especially in dry etching, the surface of the silica glass tool is also etched similarly to the treatment containing a hydrofluoric acid solution, which causes a large change in the surface state, and has disadvantages such as difficulty in controlling the etching process itself of the semiconductor device. In order to solve the above disadvantages, a silicon glass mold (Japanese Patent Application Laid-Open No. 10-59744) is proposed to open a micro-crack by etching a machined mold with a solution containing hydrogen fluoride and open the micro-cracked surface, or (3 ) (3) 200417524 is a proposal that uses a machined silica glass mold surface to make unevenness, and then treats it with a solution containing hydrogen fluoride and fluorinated money to form a depression with a depression of 20 to 300 μηι on the surface and an interval of 20 to 30 μηι, grooves with a width of 0.5 to 50 μη ′ and uniformly disperse small protrusions of silica glass molds with a width of 1 to 50 μm and a height of 0.1 to 10 μηα (Japanese Patent Application Laid-Open No. 2002-1 04 843). However, in actual use, the above-mentioned molds are used to make the concave portions become large bowl-shaped, and there is a sudden change in the amount of adhesion of by-products, or to reduce unevenness, and continued to use to some extent, peeling particles occur And so on. In view of such a situation, as a result of inadvertent research, the inventors of the present case found that the surface roughness of the silica glass mold is made from the center line average roughness Ra to 0.1 to 20 μm, and that it is also effective for slight surface etching. By making a surface with a small change in surface state, it is possible to avoid the peeling of by-products or the scattering of fine fragments of silica glass, and to reduce the change in the consumption of processing gas, making it easier to control the processing of various processes. It has also been found that the above-mentioned silica glass mold interaction can be easily manufactured by repeating specific physical-type surface-layer removal means and specific chemical-type surface-layer removal means several times, and completed the present inventor. That is, an object of the present invention is to provide a silica glass mold that does not cause particles that contaminate semiconductor elements during use and does not change processing conditions even after repeated use. Another object of the present invention is to provide a method for manufacturing a silica glass mold. [Summary of the Invention] -7- (4) 200417524 The silica glass mold of the present invention is a silica glass mold produced by the conductor engineering process, which is characterized in that: part or all of the center average roughness Ra is 0 · 1: Convex, and for a slight surface etching treatment, the surface state of the silica glass mold of the present invention is a process for manufacturing a semiconductor element such as a furnace core tube, wafer etching, deashing cavity, etc .; part or all of its surface There are irregularities with an average centerline of 0.1 to 20 μm, and a mold with little change in the state of slight surface erosion. The above-mentioned change in surface state is 3.0 to 4.0% and the liquid temperature is 17 to 23 t: hydrofluoric acid for 15 to 17 hours, and a stylus-type surface roughness measuring device using R at the front end of the stylus section to The measurement is based on the average roughness of the center line of JI SB 0 6 0 1 on the surface, and the change rate of the average roughness is preferably 50% or less. At the moment, for example, the etching by plasma gas will make the silica glass mold, but specifically, Ra will increase in the initial stage, but it is related to the average rate of the centerline indicating that the change in the surface state is small. If the rate is below 50%, the real change is still small. If the concentration of the hydrofluoric acid solution is not fully changed, it will be time-consuming and inefficient. If it exceeds the normalization speed, the judgment time will be shortened, but the water will be replaced from the solution until the surface is saturated. The temperature of the solution is 17 to 23 ° C, and its temperature is general. The etching treatment time is 15 to 17 hours. It is because the variation of a recess of g 2 0 μm that is half on the surface is small. The wafer boat for placing, the roughness Ra of the mold used is etched, the surface is small, and the concentration solution is etched in the range of 2 to 10 μm and the center line before the etching is flat, that is, the actual etched surface If there is a change, the magnitude of the change is a change in roughness. When the above range of Ra is used, the measurement object is initially changed to the range. In addition, hydrofluoric acid was used. The time required to obtain the high-accuracy rate of change used in the judgment (5) (5) 200417524. The reason for measuring the above-mentioned rate of change is to use a stylus-type surface measuring device with an R of 2 to 10 μm at the tip of the stylus part according to JI s B 0 6 0 1, which is a silica glass mold in actual use. The surface state changes, and the microcracks existing on the surface in the initial state are enlarged by the etching process, or the shape of the surface is changed due to the etching of the surface irregularities. When measuring using a non-contact type measuring device such as a laser reflected light measuring device, the centerline average roughness calculated from the measured shape is correct. However, it is also detected that by-products are immediately removed during use. It is full of small and small valleys, etc., and it is difficult to understand the large state change caused by changes in processing conditions during use. Using this stylus-type surface-side measuring device, of course, it is easy to detect the change in the convex portion, and in particular, it is also easy to detect the change in the valley portion where the adhesion state of the by-product is sensitive. The R of the tip of the stylus part is 2 to 10 μιη, in order to create a range of 2 μιη from a range where fine valleys are never detected, to a range of 10 μιη which can be judged to be substantially concave and convex, and can be easily measured and adapted to actual conditions Changes in the surface state during use. In the actual use of silica glass molds, there is an appropriate amount of by-products corresponding to the use process. For example, during the CVD process, the excess gas of the film growth on the wafer, and During dry etching processes such as plasma, the etched reactive gas will roughen the surface of the silica glass mold and become more by-products trapped on the mold. If the accumulation amount of the by-product is too large, the gas for forming the film on the wafer is reduced to more than necessary, thereby preventing the growth or etching of the film. On the other hand, if there is less capture, particles may be generated due to peeling and the like, and depending on the roughness or state of the silica glass mold during use, it may change from the initial state of -9- (6) (6) 200417524. There are the same disadvantages as above. The surface irregularities of the silica glass mold are those in which sawtooth-like irregularities or irregularly continuous sharp-angle valleys of sawtooth or mesa-shaped protrusions are arranged, but the edge portion becomes a sharp, large bowl-like shape due to the etching treatment in actual use. Concavities and convexities, and initial state changes such as the ability to capture by-products vary greatly. In addition, when the bowl-shaped unevenness is formed from the initial state, the surface area is small, so that the trapping ability of the by-products cannot be practically used, and the sharp portion of the bowl-shaped edge portion falls off, and particles are generated. Therefore, the silica glass mold of the present invention has unevenness with a center line average roughness Ra of 0.1 to 20 μm on part or all of its surface. The presence of this unevenness' can reliably capture by-products and can suppress peeling. It is preferable that the above-mentioned concavity and convexity be a multi-layer structure having large concavities and convexities and a fine shallow bowl-shaped concavity formed on the surface. With this multi-layer structure, it is possible to capture the unevenness of the by-products of the required thickness by the large corrugated unevenness which is not easy to change in a slight uranium engraving. In addition, there is a fine shallow bowl-shaped unevenness in the large corrugated unevenness. It has a mold that fixes the captured by-products and stabilizes the surface. It is particularly desirable that the shallow bowl-shaped recessed portion is smaller than the depth of the edge of the recessed portion, and that the boundary edge portion between adjacent recessed portions is not a sharp-angled protruding portion. Accordingly, even if the recessed portion is engraved with uranium during use, the vicinity of the edge portion is uniformly reduced, and a protrusion-like chamfer that easily falls off at an acute angle with an adjacent recessed portion can be prevented. The silica glass mold of the present invention can be manufactured by repeatedly applying two or more times on the surface of silica glass alternately according to physical surface layer removal means and chemical surface layer removal means. Ideally, it is better to select processing conditions where the surface roughness formed by the physical surface layer removal means becomes smaller in order. -10- (7) 200417524 According to the fixed capsule, free capsule. In addition, as vermiculite, etc., the treatment of honing is scattered in the physical surface layer or slightly broken, and it becomes an uneven heterogeneous erosion trench, which makes the appropriate layer open and slightly change after etching or etching, but it cannot be fully desired. The damaged concave portion which is sufficiently broken and the fine glass concave portion scattered on the outer periphery is sufficiently removed by the above method, or becomes slightly broken. In addition, the sharp concavities are processed by the above-mentioned materials, and the vermiculite is honing according to the liquid. Specifically, the silica particles are dispersed and dispersed in the mold. There is also incomplete microfabrication and production. However, there are many methods for removing the layer by means of layer removal, such as plastic layer or surface layer. In particular, the process of removing the hand from the surface layer described above makes the etching surface layer used for the etching place to remove the particles from the particles, or there is a resin, or SiC, and there is silicon sprayed on the surface of the liquid silicon glass. The open rupture of the glass during the etching process must be changed to continue the above physics. In addition to the exception, the surface layer can be removed to remove the processing of the large grooves or the sharp peripheral edges of the outer periphery of the bowl. The formed natural surface has multiple removal methods, which refers to abrasion treatment, and a combination of these types of bonded diamonds as a liquid treatment. The formation of processing plastic micro-fragments will produce the deep CVD engineering-type surface layer removal during processing to reduce the processing plasticity, the surface state is small, and the amount is small. In this way, if the plastic layer or micro-shaped or thin bowl-shaped thin parts are prone to sharpening, in this method, there is no change in the state of the processed plastic layer. The damage layer such as cracking of the free layer is made of fine particles, which will cause processing conditions such as surface conditions to change. When the chemical formula table is broken, the removal will be performed according to the chemical formula table, and the physical layer will be removed. . Patent Document 2 uses a physical damage layer to make it practically easy to occur -11-(8) (8) 200417524 fine particles. The manufacturing method of the present invention is to form a surface having microcracks and openings on its surface by using a chemical formula surface layer removal method after the first physical formula surface layer removal method, for example, after forming a surface with a large number of bowls or bowl-shaped irregularities, the physical formula is then applied. The surface layer removing means forms an undulated acute-angle portion, and by applying a chemical formula surface layer removing means, a processed plastic layer remaining on a flatter surface or a micro-crack left slightly open is formed. It is preferable that the physical-type surface layer removing means and the chemical-type surface layer removing means are applied repeatedly two or more times alternately. Thus, a mold with a small change in the surface state of the silica glass mold in use is obtained. The above-mentioned physical-type surface-layer removing method is preferable, and it is preferable to select the next physical-type surface-layer removing method so that the surface roughness is smaller than the original one. In the range where the large wave-shaped uneven shape formed by this does not change much, only the next physical formula surface layer removal means is damaged or micro-ruptured. Not only the next chemical formula surface layer removal means can be easily opened, but also in a large wave shape. The uneven surface can have a multiple structure with a large number of bowl-shaped depressions. For example, larger grains are used initially, and smaller grains are used in the next removal method. At this time, it is also possible to use a combination of physical surface layer removal means such as honing treatment of free flint particles followed by honing treatment of fixed flint particles with a combination liquid. For example, after the first use of fixed particles of diamond particles containing # 1 20 diamond particles, a sandblasting treatment of SiC free particles according to # 600 can be applied. As the chemical formula surface layer removing means used in the present invention, there is a treatment based on a solution containing hydrogen fluoride, but it is more preferably a chemical formula surface layer removing means after the final physical formula surface layer removing means, and it is preferable to further include ammonium fluoride in the solution. . Therefore, the plot is not clear, but it can be made into a half by removing the bowl-like shape or the sharp protrusions of the bowl-shaped portion or other sharp-angled protrusions formed by the chemical surface removal method of chemical-12 · (9) 200417524. This may be due to the reaction of hydrogen oxide with fluorinated gold and sand glass. For example, it occurs well at the bottom of the bowl, and the crystals that do not occur at the protrusions are immediately detached. As a result, the protrusions are removed and they do not have sharp corners. In a circular shape, particles of any one or a combination of 103, grease, silicon dioxide, or ceramics are dispersed in the above-mentioned solution containing hydrogen fluoride. The particles can easily remove the damaged layer on the surface of the mold, and form energy It becomes high, and the manufacturing sequence can be simplified. Adding super-mixing means can make processing more efficient. The silica glass mold of the present invention has the effect of processing a stable high-quality semiconductor element with little change in the processing bar even when it is repeatedly used, even if it is repeatedly used. The glass mold can be easily manufactured by reapplying the specific material means and chemical surface removal means more than twice. [Embodiments] Examples of the present invention will be described below, but the present invention is limited by them. The roughness Ra of the following Example 1 and Comparative Example 1 was measured by a surface roughness meter (Surcom 300B, Tokyo Seiki, Japan). The surface roughness meter (SJ-400) manufactured by Mikasa (Other) Co., Ltd. has a concave and convex surface with a smooth outer periphery. The resulting crystals, the protrusions only absorb the selective uranium engraving, more specifically the tree of E 2 0 0 μm is preferred. The scattered and fine uneven sonic vibration or agitation can reduce the occurrence of fine particles, and it can be used and the above-mentioned silica glass surface layer is removed. The industrial price is obviously not including the center line average thickness (strand). -(10) (10) 200417524 Example 1 A 300 mm diameter quartz glass surface was bonded with vermiculite bonded with a resin containing diamond particles of # 3 00 to produce a disc-shaped dry etching tool. The average thickness f a of the center line of the obtained work t 旲 is 1.2 μm. The mold was immersed in a 50% hydrofluoric acid solution for 10 minutes. The center line average roughness Ra of the obtained die was 2.8 μm. Then the surface was removed with a resin bonded vermiculite of # 1 000 SiC particles, and the center line average roughness Ra was 0.5 μm, and then 15% by mass of hydrogen fluoride, 15% by mass of ammonium fluoride, and 5% of acetic acid. The treatment liquid consisting of 0% by mass and water was treated for one hour. The center line average roughness Ra at this time is 1.4 μm. As shown in Table 1, when the above mold was immersed in a 3.5% by mass hydrofluoric acid solution at 20 ° C to investigate the change in Ra. The photograph of the surface observed under the microscope at 0 hours is shown in Fig. 1 ', and the photograph of the surface observed under the microscope after 16 hours of starving treatment is shown in Fig. 2. In addition, a photograph observed by a scanning electron microscope at 0 hours is shown in FIG. 3. Comparative Example 1 A resin-bonded vermiculite was cut with a resin containing diamond particles of # 3 00, and the quartz glass mold similar to that of Example 1 was used to produce a disc-shaped dry etching mold. The average roughness Ra of the center line of the obtained mold was 1.2 μm. The mold was immersed in a 10% hydrofluoric acid solution for 10 minutes. Ra at this time is 1.3 μm. Table 1 shows the change of the surface roughness of the hydrofluoric acid according to 3.5 mass% of this mold in the same manner as in Example 1. (11) (11) 200417524 Table 1 0 time 4 time 8 time 16 time Example 1 Ra 1.4 μιχι 1.8 μm 1.9 μιη 1.9 μηι Change rate 0% 2 9% 3 6% 3 6% Comparative Example 1 Ra 1.3 μιη 1.9 μπι 2.8 μιη 3.3 μηι Change rate 0% 4 6% 1 1 5% 1 3 0% As is known from Table 1 above, the silica glass mold of the present invention in Example 1 is at 3.5 mass% hydrofluoric acid. In the etching test of the solution, the change in the surface state of Ra and the like was extremely small compared to Comparative Example 1. The molds according to Example 1 and Comparative Example 1 were actually put into a CF4 / Ar gas, 2 kw plasma dry etching device. The molds of Example 1 were processed in 5 batches, and the number of particles was Less than 10 in any one batch. In this regard, in the mold of Comparative Example 1, a large number of 50 or more particles were generated in the third batch, and the use was discontinued. The Ra after each use is 2 μm in the mold of Example 1 and 5.2 μm in the mold of Comparative Example 1, which is very different from the etching test of a hydrofluoric acid solution of 3.5% by mass. In addition, when comparing the etching rates of the processed wafers in the fifth batch of Example 1 and the third batch of Comparative Example 1, the molds of Comparative Example 1 have a smaller etching rate than the molds of Example i. Example 2 A wafer for vertical vapor growth corresponding to a silicon wafer having a diameter of 150 mm was produced. The crystal boat was sandblasted with # 150 SiC particles, and then treated with -15- (12) (12) 200417524 15% hydrofluoric acid solution for 20 minutes, and then sandblasted with # 600 SiC particles. Then, It treated with the treatment liquid which consists of 14 mass% of hydrogen fluoride, 12 mass% of ammonium fluoride, and water for 1 hour. The obtained boat surface was photographed with a scanning electron microscope (SEM). The results are shown in Figures 4 and 5. The roughness of the surface of the wafer boat was 2.1 μm, the center line average roughness Ra. As shown in Figs. 4 and 5, a multiple structure of shallow concave portions is formed on the surface of the large corrugated unevenness. The wafer boat was etched with a 20 t, 3.5% hydrofluoric acid solution for 16 hours. The photographs of the surface of the wafer boat after the SEM photographic test are shown in Figs. A large structure with a large wave-shaped recess is slightly wider than before, reducing the number of structures. Ra at this time is 2.1 μm. In addition, the above-mentioned wafer boat is used to deposit a 2 μm film using a vapor growth process of actual SiC. Grow on the one-piece bill of the growth process described above, and repeat the washing 5 times / hour with a 4% hydrofluoric acid solution. The surface a after use was 2.5 μm. Comparative Example 2 In the same boat as Example 2, sandblasting was performed with # 1 50 0 S i C particles, and sandblasting was performed with # 6 0 0 S i C particles. After that, the solution was treated with a 10% hydrofluoric acid solution for 1 hour. The boat surface obtained by S EM photography. The results are shown in Figs. 8 and 9. The roughness of the wafer boat is an average roughness Ra of the centerline of 2.2 μm. This wafer boat was subjected to an etching test at 20 ° C and a 3.5% hydrofluoric acid solution for 16 hours in the same manner as in Example 2. The photographs of the surface of the wafer boat after the SEM photographic test are shown in Figs. 10 and 11, but are very different from the surface of Fig. 6 in which sharply concave portions continue to have sharp concave edges, and Ra is 4.8 µm. In addition, using the above-mentioned wafer boat -16- (13) (13) 200417524 in the actual Sic vapor phase growth process, each cumulative growth of the 2 μm film was repeated 5 times per hour with a 4% hydrofluoric acid solution. Wash. The R a of the surface after use was 5.1 μm. In addition, the thickness of the film that has grown sharply on the wafer from the third time is reduced, and it is seen that the number of particles on the wafer is increased. Industrial Applicability The sand glass mold of the present invention does not cause particles that contaminate semiconductor elements during use, and does not change the number of processing conditions even after repeated use. Therefore, it can be usefully used as a furnace core tube. Wafers for circular mounting, cavities, rings, and plates for etching and ash removal. [Brief Description of the Drawings] Fig. 1 is a photograph showing a magnification of 500 times of the surface of the mold for dry etching of the example observed under a microscope. Fig. 2 is a photograph showing a 500-fold magnification of the surface of the mold for dry etching of Example 1 after being immersed in 3.5% by mass of hydrofluoric acid for 16 hours. Fig. 3 is a photograph showing the surface of the mold for dry etching of Example 1 at a magnification of 500 times observed with a scanning electron microscope. Fig. 4 is a photograph showing a 200-fold observation of the wafer boat of Example 2 with a scanning electron microscope. Fig. 5 is a photograph showing the wafer boat of Example 2 at a magnification of 1,000 times with a scanning electron microscope. FIG. 6 is a 200-times photograph observed by SEM after the wafer boat of Example 2 was subjected to an etching test with a 3.5% hydrofluoric acid solution for 17- (14) (14) 200417524 for 16 hours. Fig. 7 is a photograph of 1,000 times observed by SEM after the wafer boat of Example 2 was subjected to an etching test with a 3.5% hydrofluoric acid solution for 16 hours. Fig. 8 is a photograph showing a 200-fold observation of the wafer boat of Comparative Example 2 by SEM. Fig. 9 is a photograph showing a 1000-fold observation of the wafer boat of Comparative Example 2 by SEM. Fig. 10 is a photograph taken 200 times by SEM after the wafer boat of Comparative Example 2 was subjected to a uranium engraving test with a 3.5% hydrofluoric acid solution for 16 hours. Fig. 11 is a photograph of 1000 times observed by SEM after the wafer boat of Comparative Example 2 was subjected to an etching test with a 3.5% hydrofluoric acid solution for 16 hours.