3605twf.doc/006 3605twf.doc/006 經濟部中央標率局員工消費合作社印製 _ 一________ 五、發明説明（/ ) 本發明是有關於一種金屬內連線(metal interconnects) 的製造方法，且特別是有關於一種沈積金屬鈦於接觸窗 (contact window)的製造方法，以簡化傳統之金屬鎢插塞 (tungsten plug)的製程。 當半導體元件比如積體電路的積集度增加，使得晶片 的表面無法提供足夠的面積來製作所需的內連線時，爲了 配合金屬氧化半導體（metal oxide semiconductor;以下簡 稱MOS)電晶體縮小後所增加的內連線需求，兩層以上的 金屬層設計，便逐漸的成爲許多積體電路所必需採用的方 式。在金屬層之間常以內金屬介電（inter-metal dielectric ; 以下簡稱IMD)層加以隔離，其中用來連接上下兩層金屬 層的導線，在半導體工業上，稱之爲介層窗插塞（via plug);若是用以連接MOS元件與金屬層之間的導線，則 稱之爲接觸窗插塞（contact plug)。通常，於介電層中形 成的開口若暴露出內連線中的金屬層，則此開口稱爲介層 窗開口（via hole);若此開口暴露出基底的元件，則稱爲 接觸窗開口（contact hole)。 以下以“插塞”泛稱介層窗插塞和接觸窗插塞，以 “開口 ”泛稱介層窗開口和接觸窗開口。 習知製造插塞和金屬線（metal line)的方法有兩種， 其中一種是插塞和金屬線分兩步驟完成，即在欲行電性耦 接的區域上方形成介電層，接著利用微影蝕刻技術於介電 層內完成開口，並在此開口沈積導電材料以完成插塞；之 後沈積金屬層，並定義金屬層，以形成金屬線與插塞接觸， 3 ---------€------ΐτ------# r · (請先閱讀背而之注意事項再4寫本頁) :尺lit用中國國家標準（CNS丁八4規格（210X297公飧) 3605twf.doc/006 3605twf.doc/006 經濟部中央標隼局負工消费合作社印製 Η7 五、發明説明（〉） 最後再沈積內金屬介電層。另一種是金屬鑲嵌 (damascene)的技術，是一種插塞和金屬線同步形成的技 術。 在超大型積體電路(very large scale integration ; VLSI) 金屬化製程中，鋁與鎢爲現今較常使用的金屬材料。鋁因 爲電阻率(resistivity)較低，所以主要是作爲元件間的導線 之用，鎢則可以化學氣相沈積法（chemical vapor deposition ;以下簡稱CVD)形成，其較常應用作爲不同金屬 間的插塞之用，以便將各層金屬連接。但是，鋁和矽的界 面極易形成尖峰(spiking)現象，而鎢對其它材質的附著能力 也不十分的理想，所以在使用鋁及鎢這兩種金屬時，通常 在金屬與其它材質之間，再加入一層稱爲阻障層(barrier layer)的導電材料，比較常見的阻障層材料有氮化鈦(TiN) 與鈦鶴合金(TiW)等兩種，使接觸窗金屬(contact metal)實際 上是由氮化金屬與金屬層組合而成。 請參照第1A圖，係繪示習知之金屬內連線的主要結構 之剖面示意圖。在一半導體基底10上，形成有場氧化層 (field oxide ; F〇X)12 做爲隔離區（isolation)、閘極（gate)結構 14、以及源/汲極區(source/drain)16，並於場氧化層12之上 形成一位元線（bit line)18之結構。而絕緣層20係做爲 IMD，其材質例如爲二氧化矽。在絕緣層20中，利用鎢插 塞32做爲連接源/汲極區16、位元線18與金屬鋁層34。此 外，在絕緣層20與鎢插塞32之間，以金屬鈦層26和氮化 鈦層30做爲阻障層，而源/汲極區16的表面，形成有自行 4 冢纸疚尺度過川中國阀家標準（CNS ) Λ4Ί& ( 2丨0X297公处) "" (請先閱讀背面之注意事項再填寫本I) -56 3605twf.doc/006 3605twf.doc/006 經濟部中央標準局員工消費合作社印製 D / 五、發明説明（> ) 對準矽化鈦層28。 請參照第1B圖，係繪示習知之金屬內連線結構的局部 剖面示意圖。傳統之金屬內連線的製程中，在完成介電層 開口後，於絕緣層20之上，先後沈積金屬鈦層26和氮化 鈦層30做爲阻障層，然後，利用CVD形成鎢插塞32。其 中沈積金屬鎢之CVD，是以氟化鎢(WFO氣體做爲反應物， 而阻障層的厚度通常很薄。因此在CVD沈積鎢的過程中， 容易發生氟化鎢穿過阻障層，與基底10之矽成份反應，形 成基底10表面之側邊侵飩（lateral encroachment)36與駐洞 (wormholes)38的問題，可能造成元件發生嚴重的遺漏電流 (leakage current) 0 請參照第1C圖，係繪示習知之金屬內連線結構的局部 剖面示意圖。另一方面，氟化鎢亦容易與阻障層之金屬鈦 作用’產生氣泡狀之火山口狀物質40，影響金屬鎢之階梯 覆蓋（step coverage)甚鉅，大大降低元件之良率(yield)。 此外，習知之金屬鎢插塞製程中，係於沈積金屬鎢後， 以乾蝕刻法回蝕金屬鎢，並利用阻障層做爲蝕刻終點，再 經一刷洗(scrubber clean)步驟，以去離子水(deionized water) 淸洗阻障層與鎢插塞之表面，然後，進行金屬鋁之濺鍍 (sputtering deposition)，完成金屬內連線之製作。因此，在 金屬鎢插塞的製程中，除了氟化鎢的侵蝕問題外，步驟繁 複亦是一大缺點。 有鑑於此，本發明的主要目的就是在提供一種金屬內 連線的製造方法，且特別是有關於一種沈積金屬鈦於接觸 5 本紙張尺度適用中國國家標芈（CNS ) A4现格（210X297公釐） ---------^------、訂----- (請先閲讀背面「之注意事項再填寫本頁) 3605twf.doc/006 A7 B7 五、發明説明（y ) ~" 窗的製造方法，取代習知之金屬鎢插塞的製程，避免在金 屬插塞形成時，容易造成阻障層的破壞。 爲達成上述和其它之目的，本發明提出一種金屬插塞 的製造方法’利用金屬鈦之CVD沈積，以改善傳統之金屬 鎢插塞的問題，並簡化金屬插塞的製程》 依照本發明之一較佳實施例，提供具有絕緣層之基 底’此絕緣層中形成有接觸窗開口，且暴露出基底，包括 下列步驟：形成第一金屬鈦層於絕緣層表面與接觸窗開口 側壁；形成金屬矽化物於第一金屬鈦層與暴露出之基底 間；形成氮化鈦層於第一金屬鈦層上；形成第二金屬鈦層 於氮化鈦層上，且第二金屬鈦層塡滿接觸窗開口，並延伸 至絕緣層上；以及形成金屬層於第二金屬鈦層上。此外， 本發明並非只限定於接觸窗之金屬插塞形成，在介層窗開 口之金屬內連線製程亦相同。 爲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圖係繪示習知之金屬內連線的主要結構之剖面 示意圖； 第1B圖與第1C圖係繪示習知之金屬內連線結構的局 部剖面示意圖；以及 第2A圖至第2F圖係繪示根據本發明之一較佳實施 例，一種金屬內連線的製造流程之剖面示意圖。 6 — 本紙張尺度適用中國國家標準（CNS ) A4说格（210X297公釐） 1^ΐτ(泳 (請先閱讀背面之注意事項再填寫本頁) 經濟部中央標準局員工消費合作衽印製 A7 3605twf.doc/006 五、發明説明（穸） 圖式標記說明： 10、100 :基底 12、120 :場氧化層 14、140 :閘極 16、160 :源/汲極區 18、180 :位元線 20、200 :絕緣層 26 :金屬鈦層 28、280 :自行對準矽化鈦層 30、300 :氮化鈦層 32 :金屬鎢插塞 34、340 :金屬鋁層 36 側邊侵蝕 38 蛀洞 40 火山口狀物質 經濟部中央標準局員工消費合作社印製 220 :光阻 240a :接觸窗開口 240b :介層窗開口 260 :第一金屬鈦層 320 :第二金屬鈦層 實施例 第2A圖至第2F圖係繪示根據本發明之一較佳實施 例，一種金屬內連線的製造流程之剖面示意圖。 請參照第2A圖，提供一半導體基底100 ’於基底100 ---------|批衣------、玎------線 (請先閱讀背面之注意事項再填寫本頁) 本紙伕尺度適用中國國家標準（CNS ) A4規格（210X297公釐） A7 B7 3605twf.doc/006 五、發明説明（έ) 上形成有場氧化層120做爲隔離區、閫極結構140、以及源 /汲極區160，並於場氧化層120之上形成一位元線180之 結構。沈積一絕緣層200覆蓋整個基底100結構，例如以 低壓化學氣相沈積法(low pressure CVD ; LPCVD)，絕緣層 200之材質比如爲二氧化矽。然後，在絕緣層200之上，沈 積一層已定義之光阻(photoresist)220做爲罩幕層。 請參照第2B圖，比如以非等向性蝕刻法，在絕緣層 200中形成接觸窗開口 240a，暴露出源/汲極區160 ;以及 形成介層窗開口 240b，暴露出位元線180。 請參照第2C圖，以CVD沈積一第一金屬鈦層260， 覆蓋絕緣層200、接觸窗開口 240a與介層窗開口 240b，第 一金屬鈦層260的厚度約爲200〜400A之間。接著，進行快 速熱製程處理(rapid thermal process; RTP)，接觸窗開口 240a 中暴露之源/汲極區160表面，會形成一自行對準矽化鈦層 280。 請參照第2D圖，形成一氮化鈦層300覆蓋第一金屬鈦 層260與自行對準矽化鈦層280。 請參照第2E圖，再以CVD沈積一第二金屬鈦層320， 覆蓋氮化鈦層300，並塡滿接觸窗開口 240a與介層窗開口 240b ’完成金屬插塞的製作。其中，第二金屬鈦層32〇的 厚度約爲1000~1500A之間。 請參照第2F圖，然後，利用磁控直流濺鍍法形成一金 屬鋁層340，覆蓋第二金屬鈦層320 ’完成金屬內連線之連 接。 8 本紙張尺度適用中ϋ家標準（CNS ) A4規格（210X297公釐) ' I-------- ------1T-------線 y (請先閱讀背面之注意事項再填寫本頁) 經濟部中央標準局負工消費合作社印製 3605twf.doc/006 、 五、發明説明（/*]) —— - 因爲本發明之金屬插塞，係利用金屬鈦之沈積，所以 大爲簡化金屬內連線之製程，至於習知中做爲阻障層之氮 化鈦層300 ’依照本發明之一較佳實施例，可以省略。而 CVD沈積金屬鈦之反應，係利用氯化鈦（TiCi4)做爲反應 物，對於同爲鈦成份之阻障層並無侵蝕性，避免習知之蛀 洞、火山口狀物質等問題，大大提高良率。關於金屬鈦之 沈積，如下列之化學反應式所示：3605twf.doc / 006 3605twf.doc / 006 Printed by the Consumer Cooperatives of the Central Standards Bureau of the Ministry of Economic Affairs _________ V. Description of the Invention (/) The present invention relates to a method for manufacturing metal interconnects, In particular, it relates to a manufacturing method of depositing metal titanium on a contact window to simplify the traditional metal tungsten plug process. When the degree of accumulation of semiconductor elements such as integrated circuits increases, so that the surface of the wafer cannot provide enough area to make the required interconnects, the size of the transistor is reduced in order to match the metal oxide semiconductor (MOS) The increased interconnect requirements and the design of two or more metal layers have gradually become the necessary method for many integrated circuits. Inter-metal dielectric (IMD) layers are often used to isolate between metal layers. The wires used to connect the upper and lower metal layers are called the interlayer window plugs in the semiconductor industry ( via plug); if it is used to connect the wires between the MOS element and the metal layer, it is called a contact plug. Generally, if the opening formed in the dielectric layer exposes the metal layer in the interconnect, this opening is called a via hole; if this opening exposes the components of the substrate, it is called a contact window opening. (Contact hole). Hereinafter, the "plug" is generally referred to as a via window plug and a contact window plug, and the "opening" is generically referred to as a via window opening and a contact window opening. There are two known methods for manufacturing plugs and metal lines. One is to complete the plug and metal line in two steps, that is, to form a dielectric layer over the area to be electrically coupled. The shadow etching technology completes the opening in the dielectric layer, and deposits a conductive material in the opening to complete the plug; after that, a metal layer is deposited and the metal layer is defined to form a metal wire in contact with the plug, 3 ------- -€ ------ ΐτ ------ # r · (Please read the precautions first and then write this page): Chinese national standard (CNS Ding Ba 4 specifications (210X297)飧) 3605twf.doc / 006 3605twf.doc / 006 Printed by the Consumers ’Cooperative of the Central Bureau of Standards, Ministry of Economic Affairs Η5. Description of the invention (〉) Finally, the inner metal dielectric layer is deposited. The other is a damascene Technology is a technology in which plugs and metal wires are formed simultaneously. In the very large scale integration (VLSI) metallization process, aluminum and tungsten are the most commonly used metal materials today. Aluminum is because of its resistivity ( Resistivity) is low, so it is mainly used as a wire between components, It can be formed by chemical vapor deposition (hereinafter referred to as CVD), which is more commonly used as a plug between different metals in order to connect the layers of metals. However, the interface between aluminum and silicon is very easy to form sharp peaks ( spiking) phenomenon, and the adhesion of tungsten to other materials is not very satisfactory. Therefore, when using two metals, aluminum and tungsten, a layer called barrier layer is usually added between the metal and other materials. ) Conductive materials, the more common barrier layer materials are titanium nitride (TiN) and titanium crane alloy (TiW) and other two, so that the contact window metal (contact metal) is actually a combination of metal nitride and metal layer and Please refer to FIG. 1A, which is a schematic cross-sectional view showing the main structure of a conventional metal interconnect. On a semiconductor substrate 10, a field oxide (Fox) 12 is formed as an isolation region ( isolation), gate structure 14, and source / drain region 16, and a bit line 18 structure is formed on the field oxide layer 12. The insulation layer 20 is As IMD, its material is, for example, dioxygen Silicon. In the insulating layer 20, a tungsten plug 32 is used to connect the source / drain region 16, the bit line 18, and the metal aluminum layer 34. In addition, between the insulating layer 20 and the tungsten plug 32, titanium metal is used. The layer 26 and the titanium nitride layer 30 are used as barrier layers, and the surface of the source / drain region 16 is formed with a self-contained 4 dimensional scale, which passes through the Chinese Valve Standard (CNS) Λ4Ί & (2 丨 0X297) " " (Please read the notes on the back before filling in this I) -56 3605twf.doc / 006 3605twf.doc / 006 Printed by the Consumers' Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs D / V. Invention Description (>) Yes The quasi-silicide layer 28. Please refer to FIG. 1B, which is a schematic partial cross-sectional view of a conventional metal interconnect structure. In the traditional metal interconnection process, after the opening of the dielectric layer is completed, a metal titanium layer 26 and a titanium nitride layer 30 are deposited on the insulating layer 20 as a barrier layer, and then a tungsten plug is formed by CVD. Plug 32. Among them, CVD for depositing metal tungsten uses tungsten fluoride (WFO gas as a reactant, and the thickness of the barrier layer is usually very thin. Therefore, in the process of CVD tungsten deposition, tungsten fluoride easily passes through the barrier layer. It reacts with the silicon component of the substrate 10 to form problems of lateral encroachment 36 and wormholes 38 on the surface of the substrate 10, which may cause serious leakage current of the component. 0 Please refer to FIG. 1C It is a schematic partial cross-sectional view of a conventional metal interconnect structure. On the other hand, tungsten fluoride also easily interacts with the metal titanium of the barrier layer to generate a bubble-like crater-like substance 40, which affects the step coverage of metal tungsten. The step coverage is huge, which greatly reduces the yield of the device. In addition, in the conventional metal tungsten plug manufacturing process, after depositing metal tungsten, the metal tungsten is etched back by dry etching, and a barrier layer is used to make To the end of the etching, the surface of the barrier layer and the tungsten plug is washed with deionized water through a scrubber cleaning step, and then the metal and aluminum are sputtered to complete the gold deposition. The production of interconnects. Therefore, in the process of metal tungsten plugs, in addition to the problem of corrosion of tungsten fluoride, complicated steps are also a major disadvantage. In view of this, the main purpose of the present invention is to provide a metal interconnect Line manufacturing method, and in particular about a deposited metal titanium in contact with 5 paper sizes applicable to Chinese National Standard (CNS) A4 (210X297 mm) --------- ^ ---- -、 Order ----- (Please read the “Notes on the back side before filling out this page”) 3605twf.doc / 006 A7 B7 V. Description of the invention (y) ~ " Window manufacturing method, replacing the conventional metal tungsten The process of the plug avoids the damage of the barrier layer when the metal plug is formed. In order to achieve the above and other objectives, the present invention proposes a method for manufacturing a metal plug 'using CVD deposition of metal titanium to improve the traditional The problem of metal tungsten plugs and simplifying the process of metal plugs "According to a preferred embodiment of the present invention, a substrate with an insulating layer is provided. The contact layer opening is formed in the insulating layer and the substrate is exposed, including the following: Steps: forming the first gold A titanium layer is formed on the surface of the insulating layer and the opening of the contact window; a metal silicide is formed between the first metal titanium layer and the exposed substrate; a titanium nitride layer is formed on the first metal titanium layer; and a second metal titanium layer is formed on On the titanium nitride layer, and the second metal titanium layer fills the opening of the contact window and extends to the insulating layer; and forms a metal layer on the second metal titanium layer. In addition, the present invention is not limited to the metal plug of the contact window. The plug is formed, and the metal interconnection process at the opening of the interlayer window is also the same. In order to make the above-mentioned objects, features, and advantages of the present invention more obvious and easy to understand, a preferred embodiment is given below, in conjunction with the accompanying drawings The detailed description is as follows: Brief description of the diagram: Figure 1A is a schematic cross-sectional view showing the main structure of a conventional metal interconnect; Figures 1B and 1C are parts of a conventional metal interconnect structure Sectional schematic diagrams; and FIGS. 2A to 2F are schematic sectional diagrams illustrating a manufacturing process of a metal interconnect according to a preferred embodiment of the present invention. 6 — This paper size applies the Chinese National Standard (CNS) A4 scale (210X297 mm) 1 ^ ΐτ (swimming (please read the precautions on the back before filling this page) Printed by A7, Consumer Cooperation, Central Standards Bureau, Ministry of Economic Affairs 3605twf.doc / 006 V. Description of the invention (穸) Schematic notation: 10, 100: substrate 12, 120: field oxide layer 14, 140: gate 16, 160: source / drain region 18, 180: bit Lines 20, 200: Insulating layer 26: Metal titanium layer 28, 280: Self-aligned titanium silicide layer 30, 300: Titanium nitride layer 32: Metal tungsten plug 34, 340: Metal aluminum layer 36 Side erosion 38 Cavity 40 Printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economics of the Crater-like Material 220: Photoresist 240a: Contact window opening 240b: Intermediate window opening 260: First metal titanium layer 320: Second metal titanium layer Embodiment 2A to FIG. 2F is a schematic cross-sectional view illustrating a manufacturing process of a metal interconnect according to a preferred embodiment of the present invention. Referring to FIG. 2A, a semiconductor substrate 100 ′ is provided on the substrate 100 ------- -| Batch clothes ------, 玎 ------ line (please read the precautions on the back before filling this page) The paper scale is applicable to the Chinese National Standard (CNS) A4 specification (210X297 mm) A7 B7 3605twf.doc / 006 V. Description of the invention (field) A field oxide layer 120 is formed as the isolation region, the pole structure 140, and the source / Drain region 160, and a bit line 180 structure is formed on the field oxide layer 120. An insulating layer 200 is deposited to cover the entire substrate 100 structure, such as low pressure chemical vapor deposition (LPCVD), The material of the insulating layer 200 is, for example, silicon dioxide. Then, a defined photoresist 220 is deposited on the insulating layer 200 as a mask layer. Please refer to FIG. 2B, for example, by anisotropic etching Method, forming a contact window opening 240a in the insulating layer 200 to expose the source / drain region 160; and forming a via window 240b to expose the bit line 180. Referring to FIG. 2C, a first metal is deposited by CVD The titanium layer 260 covers the insulating layer 200, the contact window opening 240a and the via window opening 240b, and the thickness of the first metal titanium layer 260 is between about 200 and 400 A. Then, a rapid thermal process (RTP) is performed. In the contact window opening 240a 160 exposed surfaces of the source / drain region, the formation of a self-aligned titanium silicide layer 280. Referring to FIG. 2D, a titanium nitride layer, a titanium layer 300 covering the first metal layer of titanium silicide 260 is aligned with the self-280. Referring to FIG. 2E, a second metal titanium layer 320 is deposited by CVD, covering the titanium nitride layer 300, and filling the contact window opening 240a and the via window opening 240b 'to complete the fabrication of the metal plug. The thickness of the second titanium metal layer 32 is about 1000 to 1500A. Referring to FIG. 2F, a metal aluminum layer 340 is formed by a magnetron DC sputtering method to cover the second metal titanium layer 320 'to complete the connection of the metal interconnects. 8 This paper size applies CNS A4 specification (210X297mm) 'I -------- ------ 1T ------- line y (Please read the back first Please pay attention to this page, please fill in this page) Printed by the Central Bureau of Standards, Ministry of Economic Affairs, Consumer Cooperative, 3605twf.doc / 006, V. Description of the invention (/ *)) ——-Because the metal plug of the present invention uses metal Deposition, so that the process of interconnecting the metal is greatly simplified. As for the conventional titanium nitride layer 300 'as a barrier layer according to a preferred embodiment of the present invention, it can be omitted. The reaction of titanium deposited by CVD uses titanium chloride (TiCi4) as a reactant, and it is not corrosive to the barrier layer of the same titanium component, which avoids the problems of conventional pits and crater-like substances, and greatly improves Yield. Regarding the deposition of metallic titanium, it is shown in the following chemical reaction formula:
TiCl4u)+H2—Ti+HClu) 然而此後續之製程爲熟習此技藝者所熟知，且非關本 發明之特徵，故此處不再贅述。 綜上所述，本發明的特徵在於： 1. 依照本發明之一較佳實施例，CVD沈積金屬鈦之反 應，係利用氯化鈦(TiCh)做爲反應物，對於同爲鈦成份之 阻障層並無侵蝕性，避免習知之蛀洞、火山口狀物質等問 題，大大提高良率。 2. 本發明利用金屬鈦之沈積，完成金屬插塞的製作， 避免習知之金屬鎢插塞製程步驟的繁瑣，大爲簡化金屬內 連線製程。 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。 9 本纸张尺度適用中國國家標準（CNS ) /\7故格（210X 297公兑) H ! - - I I- m n I . I - I 士水-:I - , < (請先閱讀背而之注意事項再珀艿本页 -s 体 經濟部中央標準局員工消f合作社印製TiCl4u) + H2—Ti + HClu) However, this subsequent process is well known to those skilled in the art and is not related to the features of the present invention, so it will not be repeated here. In summary, the present invention is characterized by: 1. According to a preferred embodiment of the present invention, the reaction of CVD deposition of metal titanium is by using titanium chloride (TiCh) as a reactant, and the resistance to the same titanium component The barrier layer is non-erosive, avoiding problems such as the known caves and crater-like materials, and greatly improving the yield. 2. The present invention utilizes the deposition of metal titanium to complete the production of metal plugs, avoids the tedious process steps of the conventional metal tungsten plugs, and greatly simplifies the metal interconnection process. Although the present invention has been disclosed as above with a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make various modifications and decorations without departing from the spirit and scope of the present invention. The scope of protection of the invention shall be determined by the scope of the attached patent application. 9 This paper size applies to Chinese National Standards (CNS) / \ 7 Former (210X 297) H!--I I- mn I. I-I Shishui-: I-, < (Please read the back first Note for reprint on this page-printed by staff of the Central Standards Bureau of the Ministry of Sports and Economy