A7 B7 465048 A7A i twi'.d〇c/002 五、發明說明（I ) 本發明是有關於一·種在半導體元件製造中’鎢插塞的 形成方法，且特別是有關於一種在高深寬比（aspect ratio) 之介層窗開口或接觸窗開口中，鎢插褰的形成方法。 半導體元件已普遍使用在現代社會中，且實際上在各 種設備與服務中已成爲不可缺少的一部份。不過，這些元 件仍然從砂基晶片碁底製備，此较基晶片基底錯由各式的 選擇性蝕刻及沉積薄膜之製程處理，以在晶片中製作微結 構，藉以使其執行在電子應用上所需的功能。 從矽晶片生產半導體元件的過程中’有時希望在內介 電層中製作高深寬比之接觸窗開口，其塡滿鎢於其中°然 而，考量許多因素，並不希望鎢插塞與介電層之間直接接 觸。因此，通常使用一層或更多層的”阻障層"或”阻障薄膜 "，分開鎢插塞與介電層。 如第1圖中所描述之習知技術，使用傳統技術之鈦(Ti) 薄膜101塗蓋在介電層中之高深寬比開口 105。接著，使 用物理氣相沉積（PVD)技術形成氮化鈦（TiN)薄膜103。 接著參照第2圖，使用化學氣相沉積（CVD)技術沉積 毯覆式鎢金屬層1〇7 ’以塡滿開口 1〇5。最後參照第3圖， 使用氟基電漿回蝕刻製程或是化學機械硏磨步驟，從介電 層上去除鎢'氮化鈦與鈦。 — 然而’對於非常大之深寬比開口，即深寬比大於二， 其很難獲得對阻障層之共形階梯覆蓋。此不足的階梯覆蓋 可能導致在底部角落的不連續，且在化學氣相沉積的鎢沉 積期間，由於高腐蝕性之六氟化鎢氣體，造成介層窗毒化。 4 {請先閱婧背面之注意事項再填寫本頁} -----11 I 訂----- 3. 經濟部智慧財產局員工消費合作社印製 本紙張尺家標準(CNS)A4規格（210 X 297公釐） 47：l A7 五、發明說明（二） 因此，需使用更複雜且昂貴技術，如離子金屬電漿濺 鍵駄薄膜（IMP Ti)，以及有機金屬化學氣相沉積氮化鈦薄 膜（MOCVD ΤΊΝ)。不過，這些技術受限於低產率、對所需 設備需花費所有者昂貴的成本、以及低設備堪用時間。此 外，對於MOCVD，高碳內涵物（>4%)與高阻抗（大約2〇〇 微歐姆-公分）限制其在高速電路上的應用。 在半導體元件製造期間，需要一種在接觸窗開口或介 層窗開口形成鎢插塞的方法。最好，此方法需相對地費用 較低，且容易與標準半導體製造技術相結合。 因此本發明提供一種在介電層中形成鎢插塞的方法， 該介電層覆蓋於一基底結構之上。此方法包括：在介電層 上沉積一層氮化鈦。接著在介電層及氮化鈦層中形成一開 口至基底結構。然後使用選擇性沉積技術，在氮化鈦層上 且在基底結構上沉積鎢，直到開口之深寬比低於一預定 値。之後毯覆式沉積鎢覆蓋在選擇性沉積鎢上，直到塡滿 該開口。 爲讓本發明之上述和其他目的、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1圖至第3圖是繪示習知一種鎢插塞製程； 第4圖至第6圖是繪示依照本發明之鎢插塞製程；以 及 第7圖是繪示依照本發明之鎢插塞製程應用於內金屬 (請先閱讀背面之注意事項再填寫本頁) 裳-----—訂-----A7 B7 465048 A7A i twi'.d〇c / 002 V. Description of the invention (I) The present invention relates to a method for forming a 'tungsten plug in the manufacture of semiconductor elements, and particularly to a method for forming Forming method of tungsten insert in aspect window opening or contact window opening. Semiconductor components have been widely used in modern society, and in fact have become an indispensable part in various equipment and services. However, these components are still prepared from sand-based wafers, which are processed by a variety of selective etching and deposition thin-film processes compared to the base wafer substrate to make microstructures in the wafer, so that they can be implemented in electronic applications. Required features. During the production of semiconductor devices from silicon wafers, sometimes it is desirable to make contact window openings with high aspect ratios in the inner dielectric layer, which are filled with tungsten. However, due to many factors, tungsten plugs and dielectrics are not desired. Direct contact between layers. Therefore, one or more layers of "barrier layer" or "barrier film" are usually used to separate the tungsten plug from the dielectric layer. As in the conventional technique described in FIG. 1, a high aspect ratio opening 105 in a dielectric layer is coated with a titanium (Ti) film 101 using a conventional technique. Next, a titanium nitride (TiN) film 103 is formed using a physical vapor deposition (PVD) technique. Next, referring to FIG. 2, a blanket tungsten metal layer 107 ′ is deposited using a chemical vapor deposition (CVD) technique to fill the opening 105. Finally, referring to FIG. 3, tungsten-titanium nitride and titanium are removed from the dielectric layer using a fluorine-based plasma etch-back process or a chemical mechanical honing step. — However, for very large aspect ratio openings, that is, aspect ratios greater than two, it is difficult to obtain conformal step coverage of the barrier layer. This insufficient step coverage may cause discontinuities in the bottom corners, and during chemical vapor deposition of tungsten deposition, the via window is poisoned due to the highly corrosive tungsten hexafluoride gas. 4 {Please read the precautions on the back of Jing before filling out this page} ----- 11 I order ----- 3. This paper is printed on a paper ruler (CNS) A4 specification by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs (210 X 297 mm) 47: l A7 V. Description of the Invention (2) Therefore, more complicated and expensive technologies are needed, such as ionic metal plasma sputter bond rhenium film (IMP Ti), and organometallic chemical vapor deposition nitrogen Titanium thin film (MOCVD TZON). However, these technologies are limited by low yields, expensive owner costs for required equipment, and low equipment time. In addition, for MOCVD, high carbon inclusions (> 4%) and high impedance (about 200 microohm-cm) limit their application to high-speed circuits. During semiconductor device manufacturing, a method for forming tungsten plugs in contact window openings or vias in vias is needed. Preferably, this method is relatively low cost and easily integrates with standard semiconductor manufacturing techniques. Therefore, the present invention provides a method for forming a tungsten plug in a dielectric layer, and the dielectric layer covers a base structure. The method includes depositing a layer of titanium nitride on a dielectric layer. An opening is then formed in the dielectric layer and the titanium nitride layer to the base structure. A selective deposition technique is then used to deposit tungsten on the titanium nitride layer and on the base structure until the opening has a depth-to-width ratio below a predetermined 値. The blanket deposited tungsten then covers the selectively deposited tungsten until the opening is filled. In order to make the above and other objects, features, and advantages of the present invention more comprehensible, a preferred embodiment is given below in conjunction with the accompanying drawings for detailed description as follows: Brief description of the drawings: FIG. 1 FIG. 3 to FIG. 3 show a conventional tungsten plug manufacturing process; FIGS. 4 to 6 show a tungsten plug manufacturing process according to the present invention; and FIG. 7 shows a tungsten plug manufacturing process according to the present invention. Yu Nei Metal (Please read the notes on the back before filling this page)
I I IK K 3. 經濟部智慧財產局員工消費合作社印製 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） 經濟部智慧財產局員工消費合作社印製 46 Γ ^74 I ι\ν r.doc/l)U2 Α7 _Β7_ 五、發明說明（夕） 連線。 圖式之標記說明： 101 :鈦薄膜 103:氮化鈦薄膜 105 :開口 1.07 :毯覆式鎢金屬層 400 :介電層 401 :氮化鈦層 402 :基底 403 :選擇性沉積鎢 404 :開口 TiN:氮化鈦層 Metal :金屬層 較佳實施例 本發明參照第4圖能更明顯易懂，其係繪示一介電層 400形成於一基底402之上。在此所使用之術語”基底”， 如所了解的可能包含一半導體晶片、形成於晶片中之主動 與被動元件、以及形成在晶片表面上之各層。術語"基底” 表示包含形成在一半導體晶片中的元件，以及覆蓋在晶片 上的各層。 其中，介電層400可能是氧化層或氮化層之單一或混 合層，且如一般所知之內介電層（ILD)或內金屬介電層 (IMD)。形成在介電層400之上爲一氮化鈦層401，其作 用係作爲一成核層，用於稍後沉積的鎢層。注意不同於習 .......I…..— J ---------IIΊ. τ 裝 ------訂--------- - (請先閱讀背面之注意事項再填寫本頁). 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） 4650^3 4 74 I |\\ l'.d(»c/002 A7 B7 五、發明說明（t) 知之處，在形成鎢插塞之開□的微影與蝕刻之前，先在介 電層上形成氮化鈦層401。由於並不需要形成氮化鈦層401 於高深寬比之開口中，因此可使用氮化鈦層之傳統濺鍍 法。本發明之另一優點是在形成開口之前’先沉積氮化鈦 層401，由於氮化鈦層401原有的抗反射性質，可增進微 影圖案製程的邊際。 接著參照第5圖，使用傳統微影及鈾刻技術形成開口 404(亦即所知如介層窗開口）。開口典型地完全鈾穿介電層 400，向下直到下面的基底。一般基底亦可以是氮化鈦層， 在此情況，使用開口係在內金屬連線之應用。第7圖係繪 示此一應用。 接著，執行鎢層之第一沉積製程。第一沉積製程爲化 學氣相沉積鎢之一度空間選擇性沉積。選擇性沉積製程之 特色係只在矽、矽化物及金屬上沉積鎢+，但不會在氧化物 上沉積。選擇性沉積製程可在壓力約0.6 torr，溫度約在 攝氏300-400度之間，H2流速約在3000sccm，以及WF6 流速約在lOsccm。此製程可在ULVAC Ceraus (Methuen, ΜA)物理氣相沉積裝置上執行°因此，結果如第5圖所不， 金|只在氮化鈦層401與開口底部的表面形成，不論其爲矽 或是氣化鈦ΰ注意有極少的鎢沉積在介電層400的側壁上。 此選擰性沉積之效果’使開口 4〇4的深寬比明顯地降低’ 因爲在開口底部之沉積速率相對地較開口側壁高甚多。持 續執行選擇性沉積技術’直到開口之深寬比低於一預定程 度，例如是1.5或1。 7 (請先閱讀背面之注意事項再填寫本頁)II IK K 3. Printed by the Employees 'Cooperatives of the Intellectual Property Bureau of the Ministry of Economics This paper is printed in accordance with the Chinese National Standard (CNS) A4 (210 X 297 mm) Printed by the Employees' Cooperatives of the Intellectual Property Bureau of the Ministry of Economics 46 Γ ^ 74 \ ν r.doc / l) U2 Α7 _Β7_ V. Description of the Invention (Even) Connection. Description of the symbols of the drawings: 101: titanium film 103: titanium nitride film 105: opening 1.07: blanket tungsten metal layer 400: dielectric layer 401: titanium nitride layer 402: substrate 403: selectively deposited tungsten 404: opening TiN: titanium nitride layer Metal: metal layer. The preferred embodiment of the present invention can be more clearly understood with reference to FIG. 4, which shows that a dielectric layer 400 is formed on a substrate 402. The term "substrate" as used herein, as understood, may include a semiconductor wafer, active and passive components formed in the wafer, and layers formed on the surface of the wafer. The term " substrate " means including elements formed in a semiconductor wafer and the layers overlying the wafer. The dielectric layer 400 may be a single or mixed layer of an oxide layer or a nitride layer, and is generally known An inner dielectric layer (ILD) or an inner metal dielectric layer (IMD). A titanium nitride layer 401 is formed on the dielectric layer 400 and functions as a nucleation layer for a tungsten layer to be deposited later. .Attention is different from Xi ....... I… ..— J --------- IIΊ. Τ Equipment -------- Order ----------(Please Please read the notes on the back before filling this page). This paper size is in accordance with Chinese National Standard (CNS) A4 (210 X 297 mm) 4650 ^ 3 4 74 I | \\ l'.d (»c / 002 A7 B7 V. Description of the invention (t) Known, before forming the lithography and etching of the tungsten plug, a titanium nitride layer 401 is formed on the dielectric layer. Since the titanium nitride layer 401 is not required to be formed on For high-aspect-ratio openings, the traditional sputtering method of titanium nitride layer can be used. Another advantage of the present invention is that the titanium nitride layer 401 is first deposited before the opening is formed. Reflective nature The margin of the lithographic pattern process can be enhanced. Next, referring to FIG. 5, an opening 404 (also known as a dielectric window opening) is formed using conventional lithography and uranium engraving techniques. The opening is typically completely uranium penetrating the dielectric layer 400 to It goes down to the underlying substrate. Generally, the substrate can also be a titanium nitride layer. In this case, the opening is used for the inner metal connection. Figure 7 shows this application. Next, the first deposition of the tungsten layer is performed. Process. The first deposition process is a one-time spatially selective deposition of chemical vapor deposition tungsten. The characteristic of the selective deposition process is that only tungsten + is deposited on silicon, silicide, and metal, but not on oxides. Selectivity The deposition process can be at a pressure of about 0.6 torr, a temperature of about 300-400 degrees Celsius, a flow rate of H2 of about 3000 sccm, and a flow rate of about WF6 of about 10 sccm. This process can be performed on a ULVAC Ceraus (Methuen, MA) physical vapor deposition device Therefore, the result is not as shown in Figure 5. Gold is formed only on the surface of the titanium nitride layer 401 and the bottom of the opening, whether it is silicon or vaporized titanium. Note that there is very little tungsten deposited on the dielectric layer 400. On the side. The effect of selective deposition 'remarkably reduces the aspect ratio of the opening 404' because the deposition rate at the bottom of the opening is relatively much higher than the side wall of the opening. The selective deposition technique is continued until the opening aspect ratio is below one The degree of reservation, such as 1.5 or 1. 7 (Please read the notes on the back before filling in this page)
裝---I---—訂！ — !^J 經濟部智慧財產局員工消費合作社印製 本紙張尺度適(CNS)A4規格（210 X 297公釐） 4650 4 74 I l\vr.doc/(]〇2 A7 B7 五、發明說明（ί) 接著參照第6圖，由於具有低深寬比，可使用傳統的 毯覆式鎢沉積塡滿開口 404的殘餘部分，形成鎢層405。 毯覆式沉積製程壓力可在約80 torr，溫度約在攝氏400-440 度之間，H2流速約300sccm，以及WF6約15sccm。就如 此技藝所熟知，鎢的毯覆式化學氣相沉積爲”三度空間'’製 程，將迅速塡滿此開口。 注意到雖然在介層窗開口之側壁及底部沒有阻障層， 相信在氧化物側壁上使用選擇性沉積鎢，將不會造成問 題。 雖然本發明已以一較佳實施例揭露如上，然其並非用 以限定本發明，任何熟習此技藝者，在不脫離本發明之精 神和範圍內，當可作各種之更動與潤飾，因此本發明之保 護範圍當視後附之申請專利範圍所界定者爲準。 (請先閱讀背面之注意事項再填寫本頁) 裝--------訂---------^ 經濟部智慧財產局員工消費合作社印製 8 本紙張尺度適用中國國家標準（CNS)A4規格（210 297公釐）Install --- I ----- Order! —! ^ J Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs (CNS) A4 size (210 X 297 mm) 4650 4 74 I l \ vr.doc / (] 〇2 A7 B7 V. Description of the invention (Ί) Next, referring to FIG. 6, because of the low aspect ratio, the conventional tungsten blanket deposition can be used to fill the remaining portion of the opening 404 to form a tungsten layer 405. The blanket deposition process pressure can be about 80 torr, The temperature is about 400-440 degrees Celsius, the H2 flow rate is about 300 sccm, and the WF6 is about 15 sccm. As is well known in the art, the blanket chemical vapor deposition of tungsten is a "three-dimensional" process, which will quickly fill this. It is noted that although there is no barrier layer on the sidewall and bottom of the opening of the via, it is believed that the use of selective deposition of tungsten on the sidewall of the oxide will not cause problems. Although the present invention has been disclosed as above with a preferred embodiment, However, it is not intended to limit the present invention. Any person skilled in the art can make various modifications and retouches without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be regarded as the scope of the attached patent application. The definition shall prevail. (Please (Please read the notes on the back and fill in this page.) -------- Order --------- ^ Printed by the Intellectual Property Bureau Staff Consumer Cooperatives of the Ministry of Economic Affairs 8 This paper size applies to Chinese national standards (CNS ) A4 size (210 297 mm)