424002 五、發明說明（1) 本發明係有關於一種半導體積體電路（1C)的製造技 術，特別是有關於一種在化學機械研磨（chemical mechanical polishing ;CMP)處理後，能夠防止銅内連線 (Cu interconnects)表面受損的清洗方法及銅金屬雜質去 除劑。 不論何種電子元件均少不了用來傳輸電訊的金屬導 線’半導體積體電路元件亦然，各個元件必藉由適當的内 連線當作電性連接’方得以發揮所欲達成之功能。在今曰 多層内連線製程中’除了製作各層導線圖案之外，更須藉 助接觸孔（contact via)構成，以作為元件接觸區與導線 之間或是多層導線之間的聯繫通道。在内連線材質方面， 由於銅金屬的高傳導性’高延展性等優點，成為廣受矚目 的材質之一。 以下利用第Η〜2B圖所示之銅内連線的CMP及清洗製程 剖面圖，以說明習知技術。 首先’請參照第1Α圖’該剖面顯示已形成若干元件的f 半導體基底10 ’符號12表示金屬間介電層，符號丨4表示防 止銅金屬擴散至其他元件的擴散阻障層。符號丨6為利用例 如電化學沈積法（eletro-chemical deposition ;ECD)形 成的雙鑲嵌式（dual damascene)銅内連線。 然後’請參照第1 B圖’對上述銅内連線1 6施以化學機 械研磨平坦化’以形成上表面與上述金屬間介電層12略為 等高的銅内連線16a。此時，銅内連線16a與金屬間介電層 12的表面將殘留研漿與銅等金屬雜質。424002 V. Description of the invention (1) The present invention relates to a semiconductor integrated circuit (1C) manufacturing technology, and particularly to a method capable of preventing copper interconnects after chemical mechanical polishing (CMP) treatment. (Cu interconnects) surface damage cleaning method and copper metal impurity removing agent. No matter what kind of electronic component is indispensable, the metal wire used for transmitting telecommunications is also a semiconductor integrated circuit component, and each component must perform its desired function by using appropriate interconnects as electrical connections. In today's multi-layer interconnect process, in addition to making each layer of wire pattern, it is also necessary to use contact vias to form the contact channel between the component contact area and the wire or between the multi-layer wire. In terms of the material of the interconnect, it is one of the materials that has attracted much attention because of its high conductivity and high ductility. In the following, a cross-sectional view of the CMP and cleaning process of the copper interconnects shown in Figures 2 to 2B is used to explain the conventional technique. First, please refer to FIG. 1A. The cross section shows the f semiconductor substrate 10 where several elements have been formed. The symbol 12 indicates an intermetal dielectric layer, and the symbol 4 indicates a diffusion barrier layer that prevents copper metal from diffusing to other elements. Symbol 6 is a dual damascene copper interconnect formed by, for example, an electro-chemical deposition (ECD) method. Then, "refer to Fig. 1B", the above-mentioned copper interconnects 16 are subjected to chemical mechanical polishing and planarization 'to form copper interconnects 16a having an upper surface and the intermetal dielectric layer 12 having a substantially equal height. At this time, the surface of the copper interconnects 16a and the intermetal dielectric layer 12 will have metal impurities such as slurry and copper.
424002 五、發明說明（2) " ' ~ 接著’利用含有氫氧化銨（NH4〇H)鹼性溶液進行清 洗’其主要目的在於去除上述殘留的研漿固體雜質粒子。 其次’利用氫氟酸（HF)溶液以去除銅等金屬離質。 然而’上述氫氧化銨（氨水）及HF容易對銅金屬表面 過度侵餘’而導致銅内連線16a表面產生許多孔隙p〇(如第 1B圖所示）。 再者，利用HF清洗時，HF之中的氟離子可能擴散至元 件而造成嚴重的污染問題，而且其對於擴散阻障層的蝕刻 速率較高’亦有可能侵蝕擴散阻障層。 有鑑於此’本發明的目的在於提供一種内連線研磨後 的清洗方法及銅金屬雜質去除劑，不但能夠有效地去除研 漿與銅等金屬雜質，亦可防止銅内連線被侵蝕。 根據上述目的’本發明提供一種銅内連線研磨後的清 洗方法，適用於化學機械研磨後殘留研漿與銅等金屬雜質 的去除’上述清洗方法包括下列步驟：利用含有氫氧化四 甲鍵（tetra me thy 1 ammonium hydroxide ;TMAH)之溶液 以去除上述殘留研漿；以及利用含有銅抑制劑之有機酸 (organic acid)溶液以去除上述錦金屬雜質。 上述銅内連線研磨後的清洗方法，其中殘留研漿包括 氧化鋁。上述銅金屬雜質包括銅；與至少一選自鈉、鋰、 鉀、鉻、及鋁構成的族群。銅抑制劑（Cu inhibitor)例如 為三峻甲基苯（benzotriazole ;BTA)。上述有機酸例如為 檸檬酸（citric acid)、蘋果酸（malic acid)、草酸 (oxalic acid)等。424002 V. Description of the invention (2) " '~ The next step is to' wash with alkaline solution containing ammonium hydroxide (NH4OH) '. Its main purpose is to remove the above-mentioned residual slurry solid impurity particles. Secondly, a hydrofluoric acid (HF) solution is used to remove metal impurities such as copper. However, 'the above-mentioned ammonium hydroxide (ammonia) and HF are easy to excessively swell on the surface of the copper metal', resulting in many pores p0 on the surface of the copper interconnect 16a (as shown in FIG. 1B). In addition, when cleaning with HF, the fluorine ions in HF may diffuse to the elements and cause serious pollution problems, and the high etching rate of the diffusion barrier layer may also erode the diffusion barrier layer. In view of this, an object of the present invention is to provide a cleaning method and a copper metal impurity removing agent after the interconnections are polished, which can not only effectively remove metal impurities such as slurry and copper, but also prevent the copper interconnections from being corroded. According to the above object, the present invention provides a method for cleaning copper interconnects after grinding, which is suitable for the removal of residual slurry and copper and other metal impurities after chemical mechanical polishing. The above cleaning method includes the following steps: tetra me thy 1 ammonium hydroxide; TMAH) solution to remove the above-mentioned residual slurry; and an organic acid solution containing a copper inhibitor to remove the above-mentioned bromide impurities. The above-mentioned method for cleaning copper interconnects after grinding, wherein the residual slurry includes alumina. The copper metal impurities include copper; and at least one group selected from the group consisting of sodium, lithium, potassium, chromium, and aluminum. The copper inhibitor (Cu inhibitor) is, for example, benzotriazole (BTA). The organic acid is, for example, citric acid, malic acid, oxalic acid, or the like.
第5頁 424002 ' 五、發明說明（3) 上述含有銅抑制劑之有機酸溶液更包含螯合劑，其具 體例為乙二胺四乙酸（ethyene diamine tetraacetic acid ； EDTA) 〇 根據上述目的，本發明提供一種銅金屬雜質去除劑， 適用於化學機械研磨後的清洗步驟，上述去除劑包括： 100重量部的去離子水；20~40重量部的有機酸（擰檬酸）； 以及0. 01〜〇. 1重量部的銅抑制劑（三唑甲基笨）。 為了讓本發明之上述目的、特徵、和優點能更明顯易 懂’下文特舉一較佳實施例，並配合所附圖式，作詳細說 明如下： 圖式之簡單說明： 第1A〜第1 B圖係習知技術對銅内連線進行化學機械研 磨及清洗處理的製程剖面圖。 第2A〜第2B圖係本發明實施例對銅内連線進行化學機 械研磨及清洗處理的製程剖面圖。 符號之說明 100〜半導體（矽）基底； 102〜金屬間介電層; 1〇4〜擴散阻障層； 106〜化學機械研磨處理前之銅内連線； 10 6a〜化學機械研磨處理後之鋼内連線。 實施例 •以下利用第2A〜2B圖所示之銅内連線平坦化及清洗之 製程剖面® ’以說明本發明之銅内連線清洗方法的應用場Page 5 424002 'V. Description of the invention (3) The organic acid solution containing a copper inhibitor further contains a chelating agent, a specific example of which is ethylene diamine tetraacetic acid (EDTA). According to the above object, the present invention 01〜 Provide a copper metal impurity remover, suitable for cleaning steps after chemical mechanical grinding, the remover includes: 100 parts by weight of deionized water; 20 ~ 40 parts by weight of organic acid (citric acid); and 0. 01 ~ 0.1 weight part of copper inhibitor (triazolemethylbenzyl). In order to make the above-mentioned objects, features, and advantages of the present invention more comprehensible, a preferred embodiment is given below and described in detail with the accompanying drawings as follows: Brief description of the drawings: 1A to 1 Figure B is a cross-sectional view of a conventional process for chemical mechanical polishing and cleaning of copper interconnects. Figures 2A to 2B are cross-sectional views of a process of performing chemical mechanical polishing and cleaning of copper interconnects according to an embodiment of the present invention. Explanation of symbols: 100 ~ semiconductor (silicon) substrate; 102 ~ intermetal dielectric layer; 104 ~ diffusion barrier layer; 106 ~ copper interconnects before chemical mechanical polishing treatment; 10 6a ~ after chemical mechanical polishing treatment Steel interconnects. Example • The following uses the process cross-sections of the copper interconnects flattening and cleaning shown in Figures 2A to 2B to illustrate the application fields of the copper interconnect cleaning method of the present invention.
第6頁 4 2 A 002 ”产 五、發明說明（4) 合。 首先，請參照第2 A圖’該剖面顯示已形成電晶體、電 容、電阻（圖皆未顯示）等元件的半導體基底100，符號1〇2 表示低介電常數材料之金屬間介電層（IMD),符號1〇4表示 防止銅金屬擴散至其他元件的擴散阻障層（diffusion barrier layer)，其例如由氮化组（TaN) /组構成。而符號 106為利用例如電化學沈積法（ECD)形成的雙鑲嵌式銅内連 線。 然後，請參照第2B圖，對上述銅内連線106施以化學 機械研磨平坦化，以形成上表面與上述金屬間介電層102 略為等高的銅内連線106a，上述化學機械研磨是在適當的 操作條件下，採用含有氧化銘（Al2〇3)之研漿（slurry)以進 行。此時’銅内連線l〇6a與金屬間介電層102的表面將殘 留研漿與銅等金屬雜質。 接著’利用含有氫氧化四曱銨（TMAH)之鹼性溶液（pH大 於10)進行清洗，其主要目的在於去除上述殘留的研漿固 體雜質粒子。 其次’利用本發明提供的含有銅抑制劑之有機酸溶 液’以去除銅等金屬雜質。上述含有銅抑制劑之有機酸溶 液例如由100重量部的去離子水；20〜40重量部的檸檬酸 (有機酸）；0. 01〜〇 · 1重量部的三唑甲基苯（銅抑制劑）組 成。再者’上述銅等金屬雜質除了銅金屬之外，亦可能包 含鈉、鋰、鉀、鉻、及鋁等金屬。 為了提昇金屬離子的去除效果，也可以視需要在上述Page 6 4 2 A 002 "Production 5. Description of the invention (4). First, please refer to Figure 2A '. This section shows the semiconductor substrate 100 where components such as transistors, capacitors, resistors (not shown) have been formed. The symbol 10 refers to an intermetal dielectric layer (IMD) of a low dielectric constant material, and the symbol 104 refers to a diffusion barrier layer that prevents copper metal from diffusing to other elements, for example, a nitride group (TaN) / group structure. The reference numeral 106 is a dual-inlaid copper interconnect formed by, for example, an electrochemical deposition method (ECD). Then, referring to FIG. 2B, the above-mentioned copper interconnect 106 is subjected to chemical mechanical polishing. The planarization is performed to form a copper interconnect 106a having an upper surface and the intermetal dielectric layer 102 having a substantially equal height. The above-mentioned chemical mechanical polishing is performed using a slurry containing an oxide indium (Al203) under appropriate operating conditions ( slurry) to carry out. At this time, the surface of the copper interconnects 106a and the intermetal dielectric layer 102 will remain with metal impurities such as slurry and copper. Next, the alkaline solution containing tetraammonium hydroxide (TMAH) will be used. (PH greater than 10) The main purpose of cleaning It is used to remove the above-mentioned residual slurry solid impurity particles. Secondly, "using the organic inhibitor solution containing copper inhibitor provided by the present invention" to remove metal impurities such as copper. The organic acid solution containing copper inhibitor is, for example, 100 parts by weight. Ionized water; 20 ~ 40 parts by weight of citric acid (organic acid); 0.01 ~ 〇 · 1 parts by weight of triazole methylbenzene (copper inhibitor). Furthermore, the above-mentioned metal impurities such as copper except copper metal In addition, it may also contain metals such as sodium, lithium, potassium, chromium, and aluminum. In order to improve the removal effect of metal ions, you can also add
Λ2Λ 00^_______ 五、發明說明（5) _ 含有銅抑制劑之有機酸溶液之中添加適量的乙二胺四乙酸 (EDTA)等螯合劑（chalet agent)。 本發明利用金屬污染測試（TXRF) ’以測得殘留之金屬 量，由此測試可確認本發明銅金屬雜質之去除劑的效果優 於習知技術之氫氟酸。 發明特徵與效果 本發明利用氫氧化四甲銨（TM A Η )之鹼性溶液取代傳統 的氫氧化敍，以去除研漿之固體粒子。益且利用特定的有 機酸溶液當作鋼金屬雜質之去除劑，以取代傳統的氫氟酸 溶液。 藉此，不但能夠有效地去除研漿與銅等金屬雜質，亦 可防止銅内連線被侵蝕。再者，亦可避免氟離子引起的污 染問題。 〜雖然本發明已以較佳實施例揭露如上，然其並非用以 2夂本發明，任何熟習此項技藝者，在不脫離本發明之精 春圍内，當可作更動與潤飾，因此本發明之保護範圍 田視後附之申請專利範圍所界定者為準。Λ2Λ 00 ^ _______ 5. Description of the invention (5) _ Add an appropriate amount of a chelet agent such as ethylenediaminetetraacetic acid (EDTA) to the organic acid solution containing a copper inhibitor. In the present invention, a metal contamination test (TXRF) is used to measure the amount of remaining metal. From this test, it can be confirmed that the effect of the remover of copper metal impurities of the present invention is better than that of hydrofluoric acid in the conventional technology. Features and Effects of the Invention The present invention uses a basic solution of tetramethylammonium hydroxide (TM A Η) instead of the traditional hydroxide to remove the solid particles of the slurry. It also uses a specific organic acid solution as a remover of steel metal impurities to replace the traditional hydrofluoric acid solution. This not only effectively removes metal impurities such as slurry and copper, but also prevents copper interconnects from being corroded. Furthermore, the problem of contamination due to fluoride ions can also be avoided. ~ Although the present invention has been disclosed as above with a preferred embodiment, it is not intended to be used in the present invention. Any person skilled in the art can make changes and decorations without departing from the fine spring enclosure of the present invention. The scope of protection of the invention shall be determined by the scope of the patent application attached to it.
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