543109 五、發明說明（l) 發明領域 本發明係有關於半導體積體電路之製造技術，特別是 有關於形成一種使用電化學蝕刻瓶型溝槽之方法。 相關技術之描述 一般而言，目前廣泛使用之動態隨機存取記憶體 (Dynamic Rand〇m Access Memory; DRAM)中的電容器係 由兩導電層表面（即電極板）隔著一絕緣物質而構成了該 電容器儲存電荷之能力係由絕緣物質之厚度、電極板之2 面積及絕緣物質的電氣性質所決定。隨著近年來半導體^ 程設計皆朝著縮小半導體元件尺寸以提高密度之方向發、 展’記憶體中記憶胞的基底面積必須不斷減少使積體電路 能容納大量記憶胞而提高密度，但同時，記憶胞電容之電 極板部分必須有足夠之表面積以儲存充足的電荷。 然而在尺寸持續地細微化的情況下，動態隨機存取記 f思體中的溝槽儲存結點電容（t r e n c h s t 〇 r a g e η。d e capacitance)亦隨著縮小，因此必須設法增加儲存電容以 維持記憶體良好的操作性能。 目前已廣泛使用於增加DRAM之儲存電容的方法，例如 藉由增加溝槽底部的寬度以提高表面積形成一瓶型電容口 (bottle shaped capacitor)。以下就習知的瓶型溝槽的 製造方法說明如後，首先，請參閱第丨A圖，先於一矽"基底 10上形成一墊層（pad layer )12圖案，然後以該墊層12"'圖一 案為I虫刻罩幕，利用乾蝕刻方式而於該矽基底丨〇中形成一543109 V. Description of the invention (l) Field of the invention The present invention relates to the manufacturing technology of semiconductor integrated circuits, and particularly to a method for forming a bottle-type trench using electrochemical etching. Description of related technologies Generally speaking, a capacitor in a dynamic random access memory (DRAM) currently widely used is composed of two conductive layer surfaces (ie, electrode plates) with an insulating material interposed therebetween. The capacity of the capacitor to store charge is determined by the thickness of the insulating material, the area of the electrode plate, and the electrical properties of the insulating material. With the recent development of semiconductor process design, the size of semiconductor elements has been reduced to increase the density. The base area of memory cells in memory must be continuously reduced so that integrated circuits can accommodate a large number of memory cells to increase density, but at the same time, The electrode plate portion of the memory cell capacitor must have sufficient surface area to store sufficient charge. However, in the case of continuous miniaturization, the trench storage node capacitance (trenchst η.de capacitance) in the dynamic random access memory f also decreases, so it is necessary to find ways to increase the storage capacitance to maintain memory. Good operating performance. Methods for increasing the storage capacitance of DRAMs have been widely used, such as forming a bottle shaped capacitor by increasing the width of the bottom of the trench to increase the surface area. The following is a description of a conventional method for manufacturing a bottle-shaped groove. First, please refer to FIG. 丨 A, a pad layer 12 pattern is formed on a silicon substrate 10, and then the pad layer is formed. 12 " The picture is a worm-etched mask, and a dry etching method is used to form a silicon substrate.
543109 五、發明說明（2) " 下部周圍部 j槽Η，該溝槽14具有一上部周圍部“與 然後，請參閱第1B圖，例如先沉積一 一 於部分該溝槽14内而覆蓋住該溝槽14之下C未圖不) 並可延伸至“二槽14上部周圍部16上， 以及非專向性去除位於日未圖不） 如此，即形成複曰矽播μ 矽犧牲層20。 上。$成稷-矽犧牲層20於溝槽“之上部周圍糾 去Μ接贫著」進行一濕蝕刻製程（亦稱wet bottle蝕刻制 :二^生蝕刻未被複晶秒犧牲層2°保護的溝槽14 Ϊ側 示而形成類似瓶狀的溝槽14之下部周圍丄側 然而上述製程之複晶石夕犧铋 較大之瓶型溝㉟，且所心；：：”度有限難以餘刻出 成深溝槽再製作瓶型溝槽，由蝕以^別之製程先形 槽，而無法形成深溝槽：且=刻製程會形成錐形溝 的與曰倶㉟，而難以到達溝C子隨著深溝槽深度 的溝槽，之後餘刻製程即停止；' 只此挖出約7微米深 而增加製程的困難度。 發明之概述及目的 有鏗於此，本發明提供一種 之方法，係利用電化學蝕刻機制 瓶型溝槽。 使用電化學蝕刻瓶型溝槽 採取單一步驟方式來形成543109 V. Description of the invention (2) " The lower peripheral part j trough, the trench 14 has an upper peripheral part " and then, please refer to FIG. 1B, for example, first depositing one part of the trench 14 and covering C is located below the trench 14 (not shown) and can be extended to "the upper peripheral portion 16 of the second trench 14 and the non-specific removal is located at the end of the day.) So, a polysilicon μ silicon sacrificial layer is formed 20. on. $ 成 稷 -Silicon sacrificial layer 20 performs a wet etching process (also known as wet bottle etching: the second etching is not protected by the polycrystalline second sacrificial layer 2 °) on the trench "remove the M around the upper part". The groove 14 is shown on the side of the groove to form a bottle-shaped groove around the lower side of the groove 14 which is similar to a bottle. However, the above-mentioned process is a bottle-shaped groove with a large bismuth and sacrificial bismuth. Deep grooves are made and bottle-shaped grooves are made. The grooves are shaped by etch and other processes, but deep grooves cannot be formed: and = the engraving process will form a tapered groove and a groove, and it is difficult to reach the groove The trench is deep at the depth of the trench, and the manufacturing process is stopped after that; 'It is only necessary to dig a depth of about 7 microns to increase the difficulty of the process. The summary and purpose of the invention are heretofore, the present invention provides a method for making use of Electrochemical etching mechanism of bottle-shaped grooves. Electrochemical etching of bottle-shaped grooves in a single step
543109 五、發明說明（3) 溝栌之2上述目的，本發明揭示一種使用電化學蝕刻瓶型 之^危法，包括下列步驟··提供一具有墊層結構及溝槽 用ί化與!I ^述溝槽之側壁上形成一蝕刻停止層；以及使 化與^ = u J將上述溝槽蝕刻成一瓶型溝槽，其中上述電 化學蝕刻機制為： ％ 6HF+Sl ^-+^ + 41^+26- 懂，^ ^ ^ ^明之上述目的、特徵、和優點能更明顯易 明如下：特牛一較佳實施例，並配合所附圖式，作詳細說 實施例 種 # ffi : f :第2Α至冗圖’其顯示本發明之實施例中， 使用電化丰蝕刻瓶型溝槽之方法。 半導體ί 第2Α圖，在—基底，例如是由碎構成的 102 M 形成一由氮化物層104和墊氧化物層 、曰結構106。例如是以熱氧化法（thermal 〇X1da 形成厚度大約為〗〇〇埃的塾氧化物層（_ 〇X1de)102。其次，利用化學氣相沉 104於墊氧化物層102上。然後 ^成鼠化物層 圖案（未顯示）於氮化物層104上。阻 ”二Ϊ去除未被光阻圖案覆蓋之氮化物層104和位於 其底下的塾氧化物層102，形成一具有溝槽圖案而由氮化 〇548-7712TWF(N);90141;ycchen.ptd 第6頁 543109543109 V. Description of the invention (3) Gully 2 The above-mentioned purpose, the present invention discloses a method for using a galvanic etching bottle type, including the following steps: · Providing a cushion structure and a groove for the lithography and! ^ An etch stop layer is formed on the sidewall of the trench; and 化 = u J to etch the trench into a bottle-shaped trench, wherein the above-mentioned electrochemical etching mechanism is:% 6HF + Sl ^-+ ^ + 41 ^ + 26- Understand, ^ ^ ^ ^ The above-mentioned purpose, characteristics, and advantages of the Ming can be more obvious and easy to clarify as follows: a special embodiment of the special cow, and in conjunction with the accompanying drawings, the embodiment # ffi: f : 2A to redundant drawings' which show a method for etching bottle-shaped trenches using Dianfeng in the embodiment of the present invention. FIG. 2A of the semiconductor. In the substrate, for example, 102 M composed of chips is formed into a nitride layer 104 and a pad oxide layer, ie, a structure 106. For example, a thermal oxidation method (thermal OX1da) is used to form a hafnium oxide layer (_ OX1de) 102 with a thickness of about OO Angstroms. Second, a chemical vapor deposition 104 is used on the pad oxide layer 102. Then, a rat is formed A nitride layer pattern (not shown) is formed on the nitride layer 104. The "resistance" layer removes the nitride layer 104 and the hafnium oxide layer 102 underneath the photoresist pattern to form a trench pattern formed by nitrogen. Chem. 0548-7712TWF (N); 90141; ycchen.ptd Page 6 543109
物層104和墊氧化物層1〇2構成之墊層結構1〇6。然 光阻圖案和墊層結構丨〇6作為蝕刻罩幕，蝕刻去除 2 層結構1 0 6覆蓋之基底1 〇 〇，例如利用反應離子蝕刻法 (ReaCtlVe Ion Etching; RIE)，而蝕刻出一溝槽1〇8。 後，將光阻去除，其結果如第2A圖所示。 " 。之 其次’請參照第2Β圖，於溝槽1〇8内形成一蝕刻停止 層1 1 0 ’例如利用低壓化學氣相沈積法以形成一氮化 層0 接著，請參照第2 C圖，去除|虫刻停止層11 〇之底部以 於溝槽108之側壁上留下蝕刻停止層11〇。/例如利用"*非°等向 性蝕刻法完成。 ^ 然後’凊參照弟2 D圖’將基底1 〇 〇置於一電化學餘刻 裝置120中，並於基底丨00上方懸空放置一陰極，且將基底 1 00之底部接上陽極，使用電化學蝕刻通入適當之電流進 行深度蝕刻（deep trench)將溝槽1〇8蝕刻成一深溝槽 112。電化學蝕刻裝置120中具有一電化學蝕刻液丨22 f電 化學蝕刻液1 2 2包括，氳氟酸、氫氟酸加乙醇、氫氟酸加 水、或氫氟酸加乙醇及水。本發明實施例之電化學钱刻機 制為： 6HF+S1 SiF62-+H2 +41^+26- 最後，請參照第2 E圖，繼續將基底1 〇 〇置於電化學餘 刻裝置1 2 0中，使用電化學蝕刻將深溝槽11 2 I虫刻成瓶塑溝A pad structure 106 composed of an object layer 104 and a pad oxide layer 102. However, the photoresist pattern and the pad structure are used as an etching mask, and the substrate covered by the two-layer structure 106 is etched and removed. For example, a trench is etched using ReaCtlVe Ion Etching (RIE). Slot 108. Then, the photoresist is removed, and the result is shown in FIG. 2A. ". Secondly, please refer to FIG. 2B to form an etch stop layer 1 1 0 in the trench 108. For example, a low-pressure chemical vapor deposition method is used to form a nitride layer 0. Next, refer to FIG. 2C to remove The bottom of the etch stop layer 110 is to leave an etch stop layer 11 on the sidewall of the trench 108. / For example, using " * non ° isotropic etching method. ^ Then “refer to the 2D drawing”, place the substrate 100 in an electrochemical etching device 120, and place a cathode suspended above the substrate 丨 00, and connect the bottom of the substrate 100 to the anode. A deep trench is etched by applying an appropriate current for deep etching to etch the trench 108 into a deep trench 112. The electrochemical etching device 120 has an electrochemical etching solution 22 f. The electrochemical etching solution 12 includes fluorinated acid, hydrofluoric acid plus ethanol, hydrofluoric acid plus water, or hydrofluoric acid plus ethanol and water. The electrochemical money engraving mechanism of the embodiment of the present invention is: 6HF + S1 SiF62- + H2 + 41 ^ + 26- Finally, please refer to FIG. 2E, and continue to place the substrate 100 in the electrochemical remaining device 1 2 0 In the process, the deep groove 11 2 I was engraved into a bottle plastic groove using electrochemical etching.
0548-7712TWF(N);90141;ycchen.ptd 第7頁 543109 五、發明說明（5) 槽114 〇須注意的是， 、 --- 槽之方法可以為里 發明管' Αϊ 114。 —步领而將溝样;otf化學蝕刻瓶型溝 本發明實施例係利m 瓦生溝才曰 式來形成深溝槽與沲 電化學餘刿她生丨 罝 ^ ^ , 瓦裂溝施 刻機制採取| 一牛跡七0548-7712TWF (N); 90141; ycchen.ptd Page 7 543109 V. Description of the invention (5) Tank 114 〇 It should be noted that the method of the tank can be the invention tube 'Αϊ 114. —Step-by-step and groove-like; otf chemically etched bottle-shaped grooves. The embodiment of the present invention is to create deep grooves and electrochemistry to form deep grooves. 沲 ^ ^, the mechanism of tile cracking engraving Taken | One Bull Trail Seven
成本較低。 …斤須製程較傳絲I 雖然本發明已以，社 車乂傳統方法更簡 限定本發日月’任何熟‘二’施例揭露如上，缺 神和範圍内，舍可作承項技藝者，在不脱…、並非用以 田7作更動與潤飾 m 脫離本發明之精 ¥視後附之申請專利範圍所界定者為$本發明之保護範圍Cost is lower. … The process of making a catty muster is more than that of silk. Although the present invention has been adopted, the traditional method of the social car is simpler and more restrictive. If you do not take it off, do not use Tian 7 to make changes and retouch m. Depart from the essence of the present invention. ¥ The scope of the present invention is defined by the scope of the attached patent.
543109 圖式簡單說明 第1 A至1 C圖係顯示傳統形成瓶型溝槽之方法的製程剖 面圖。 第2A至2E圖係根據本發明實施例之使用電化學蝕刻瓶 型溝槽的製程剖面圖。 符號說明 1 0 0〜半導體基底； 1 0 2〜墊氧化物層； 1 0 4〜氮化物層； 1 0 6〜墊層結構； I 0 8〜溝槽； 11 0〜蝕刻停止層； II 2〜深溝槽； 11 4〜瓶型溝槽； 1 2 0〜電化學蝕刻裝置；1 2 2〜電化學蝕刻液。543109 Brief Description of Drawings Figures 1A to 1C are cross-sectional views showing the process of a conventional method for forming a bottle groove. Figures 2A to 2E are cross-sectional views of a process of electrochemically etching a bottle-shaped trench according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 100 to semiconductor substrate; 102 to pad oxide layer; 104 to nitride layer; 106 to pad structure; I 0 to 8 trench; 110 to etch stop layer; II 2 ~ Deep groove; 11 4 ~ Bottle groove; 12 ~ 0 ~ Electrochemical etching device; 12 ~ 2 ~ Electrochemical etching solution.
0548-7712TWF(N);90141 ;ycchen.ptd 第9頁0548-7712TWF (N); 90141; ycchen.ptd p. 9