4 2 637^f4 d oc/00 2 A7 B7 經濟部智慧財產局員工消费合作社印紫 五、發明說明（f) 本發明是有關於一種高深寬比元件接觸窗之製造方 法，且特別是有關於一種高深寬比(high aspect ratio ; HAR) 無邊界接觸窗(borderless contact)之製造方法。 在現今半導體製程中，爲提高元件的積集度，元件尺 寸邁入線寬爲〇·25μιη，甚至包含0_18μπι以下的製程，而 在縮減尺寸方面，目前新的製程多採用以無邊界接觸窗結 構取代傳統接觸窗的形成方式，以有效地降低元件尺寸， 然而無邊界接觸窗在形成的過程中，對於其控制接觸窗蝕 刻終點上仍有些困難有待克服與改進。對於埋入式動態隨 機存取記憶體（E-DRAM)而言，則無法避免地需要製作高 深寬比(約大於六比一）之元件接觸窗口。 第1Α圖至第1C圖繪示習知一種無邊界接觸窗的製 造流程剖面圖。請參照第1Α圖，首先，提供一基底10， 於基底10上形成有元件隔離結構11，例如爲淺溝渠隔離 (shallow trench isolation，STI)結構，再於基底 1〇 主動區上 形成M0S電晶體12和其源/汲極區13。之後，於基底10 表面形成氮化矽層14，此氮化矽層14可在形成接觸窗的 過程中作爲蝕刻終點，以避免過度蝕刻而破壞元件隔離結 構。之後，再於基底10表面形成氧化砂層15(〇xide layer)。 接著，請參照第1B圖，利用微影蝕刻技術在氧化矽 層15上定義接觸窗開口 16之圖案。接著，以氮化矽層14 爲鈾刻終止層，採用飩刻步驟Π以形成開口 16，而暴露 出氮化砂層14。 請參照第1C圖，完成氧化矽層15的蝕刻步驟後，去 請 先 閱 讀 背4 2 637 ^ f4 d oc / 00 2 A7 B7 Printed by the Consumers ’Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs. 5. Description of the invention (f) The present invention relates to a method for manufacturing a high-aspect-ratio element contact window, and in particular, it relates to A method for manufacturing a high aspect ratio (HAR) borderless contact window. In the current semiconductor manufacturing process, in order to improve the accumulation of components, the component size has been moved to a line width of 0.25 μm, and even includes processes below 0-18 μm. In terms of reducing the size, the current new processes mostly use a borderless contact window structure. It replaces the traditional way of forming the contact window to effectively reduce the size of the component. However, in the process of forming a borderless contact window, there are still some difficulties to be overcome and improved in controlling the endpoint of the contact window etching. For embedded dynamic random access memory (E-DRAM), it is inevitable to make a component contact window with a high aspect ratio (about greater than six to one). Figures 1A to 1C show cross-sectional views of a conventional manufacturing process of a borderless contact window. Please refer to FIG. 1A. First, a substrate 10 is provided, and an element isolation structure 11 is formed on the substrate 10, such as a shallow trench isolation (STI) structure, and then a MOS transistor is formed on the substrate 10 active region. 12 and its source / drain region 13. Thereafter, a silicon nitride layer 14 is formed on the surface of the substrate 10, and the silicon nitride layer 14 can be used as an etching end point during the formation of the contact window to avoid over-etching and damaging the device isolation structure. After that, an oxide sand layer 15 (Oxide layer) is formed on the surface of the substrate 10. Next, referring to FIG. 1B, a pattern of a contact window opening 16 is defined on the silicon oxide layer 15 using a lithography etching technique. Next, the silicon nitride layer 14 is used as a uranium etch stop layer, and an etch step Π is used to form an opening 16 to expose the nitrided sand layer 14. Please refer to FIG. 1C. After the etching step of the silicon oxide layer 15 is completed, please read it.
I 訂 竣 本紙張尺度適用中0國家標準（CNS)A4規格（210 X 297公釐） 經苽部智慧財產局員工消费合作社印製 4 2 6^丨4。·2 A7 B7 五、發明說明（1) 除氮化矽層14而暴露出源極/汲極區13，完成接觸窗開口 16a之製程。 請參照第2A至2D圖，在上述對氧化矽層的蝕刻步 驟中，氧化物對氮化物的蝕刻選擇比（oxide to nitride selectivity)是影響接觸窗16之輪廓形成好壞的重要因素。 不當的蝕刻選擇比會造成蝕刻氧化矽層時其終點不容易停 在氮化矽層14上，例如過度蝕刻氮化矽層所形成之開口 21(如第2A圖所示），或未達蝕刻終點即停止蝕刻情形所 形成之開口 18(如第2B圖所示），或形成底端尖細（taper) 的開口 19(如第2C圖所示），但是卻會造成開口底部之面 積縮小且造成高接觸電阻値。然而習知技藝採用不適當的 蝕刻選擇比’在蝕刻氧化物的過程中不易控制其蝕刻的終 點，因此容易產生上述的情形，而致使後續塡充導電層時 產生電性的問題。若此製程需要高選擇性，且要停止在氮 化矽層上’則在底端尖細之開口之製程中，同樣也無法有 效改善氮化矽層之蝕刻選擇性。 此外，爲了因應兀件積集度的需要，業者逐漸致力於 形成接近90度（89度）的垂直輪廓(veriicai pr〇fiie)的接觸 窗開口以符合設計規則（design rule)的要求。然而習知技 藝形成接近90度的垂直輪廓接觸窗開口時，在上述之餓 刻條件下，其頂端角落處容易沈積高分子薄膜，影響蝕刻 的非等向性而容易形成圓胖曲折輪廓（b〇wing pr〇file)的開 2 20(如第2D圖所示），致使後續塡充導電層時其階梯覆 盍倉t；力不佳而導致空隙（void)的生成，造成元件接觸不良 4 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公度 (請t閲讀背ΐβ之沒意事項再填寫本頁) 裝------—訂--------竣 a —^^TTtwf). doc/0 0 2 /17 4 269 5 4 ____B7_____ 五、發明說明（7) 等情形。 然而在電漿蝕刻製程中，高蝕刻選擇比與形成垂直輪 廓的接觸窗開口往往不能同時兼顧，因此習知無邊界接觸 窗的触刻技術通常視需要而決定取捨其中之一條件11 本發明提供一種高深寬比元件接觸窗或介層窗之製造 方法，此製造方法包括使用一蝕刻製程，此蝕刻製程係於 一反應室中進行，此蝕刻製程包括：使用一 C4F8/Ar/CO 混合氣體或者是C4F8/C2F6/Ar/CO混合氣體作爲一蝕刻氣 體源，以及控制C4F8、Ar、C0氣體流量分別約爲10〜20 seem、100〜500sccm、1〜lOOsccm，且 C2F6/C4F8 氣體流量 比値約爲0.5〜1.5，其中反應室包括：器壁溫度約爲 150〜400°C;壓力約爲 4mTorr至 lOOmTorr;偏壓（Bias Power) 約爲 lOOOwatts 至 2000watts :功率約爲 1500watts 至 3000watts ;頂蓋溫度約爲l5〇°C至300°C ;套環溫度約爲 150eC至400。0 ;以及冷卻機溫度約爲-20°C至20°C。 經濟部智慧財產局員工消费合作社印製 本發明可在高氧化物對氮化物的蝕刻選擇比下形成_ 直輪廓的接觸窗開口，而不需犧牲任何一個條件，以避g 習知技藝中容易過度蝕刻或未達蝕刻終點即停止蝕刻等彳胃 形，或形成曲折輪廓的接觸窗而導致元件漏電與接觸_$ 値不穩定的現象。 本發明提供一種高深寬比元件接觸窗的製造方法> % 控制所需的接觸窗輪廓。 爲讓本發明之上述和其他目的、特徵、和優點能 顯易懂，下文特舉一較佳實施例，並配合所附圖式，作_ 5 本紙張尺度適用争固國家標準（CNS)A4規格（210 X 297公釐） 4 2 g9 5 fl.doc/002 A7 B7 經濟部智慧財產局員工消費合作杜印製 五、發明說明（r) 細說明如下： 圖式之簡單說明： 第1A圖至第1C圖繪示習知一種高深寬比無邊界接 觸窗之製造流程剖面圖。 第2A圖至第2D圖繪示四種高深寬比無邊界接觸窗 之形成輪廓。 第3A圖至第3C圖繪示依據本發明較佳實施例一種 高深寬比無邊界接觸窗之製造流程剖面圖。 第4圖繪示依據本發明較佳實施例一種ICP高密度電 漿蝕刻機台。 圖式之標記說明： 10、 30 :基底 11、 31 :元件隔離結構 12、 32 : MOS電晶體 13、 33 :源極/汲極區 14、 34 :氮化砂層 15、 35 :氧化矽層 16、 16a、36、36a :接觸窗 40 :頂端 42 :基座 44 :套環 4 6 :冷卻機 48 :反應室 17 :傳統蝕刻步驟 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） ------------- ^ · ---- I I 訂--------^ (諳先閲讀免面之注意事項再填寫本頁) 4277twfl.doc/〇〇2 A7 五、發明說明（夕） 37 :本發明之蝕刻歩驟 18、19、20、21 : _口 實施例 第3A fflgm 3C： 細本龍雌實施例—種 高深寬比無邊界接觸窗之製造流程剖面圖。 請參照第3A圖，首先提供一基底3〇，基底3〇上已 形成元件隔離結構31 ’其材料例如爲氧化物、高密度電漿 氧化物、碟砍玻璃或常壓化學氣相沉積氧化物。在元件隔 離結構31所定義出的主動區上已形成有一電晶體結構或 其他元件結構32。此電晶體結構32具有一源極/汲極區 33。之後’於基底30袠面例如以低壓化學氣相沈積法 (LPCVD)或電獎增益化學氣相沉積法（pECVD)沈積氮化矽 層34，作爲定義接觸窗時之終點。之後，再於基底3〇表 面形成氧化矽層35 ’其材料例如爲LpCVD氧化物、高密 度電獎氧化物、磷砂玻璃或常壓化學氣相沉積氧化物或硼 磷矽玻璃。而氧化砂層35需一較厚的厚度，以完全覆蓋 基底30上之電晶體結構32，而提供隔離的效果。 請參照第3B圖，接著，利用微影製程在介電層35上 形成圖案化之罩幕層(未繪示），用以定義接觸窗開口 36之 圖案。接著’進行氧化矽層35的蝕刻步驟37，以氮化矽 層34作爲蝕刻中止層，而暴露出氮化矽層34以形成開口 36 〇 有別於習知之作法，本發明之蝕刻步驟37係例如使 用具高密度電漿之電感式耦合電漿蝕刻機台（ICP high 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） — — — If----- *---IIn --— — — — — — (請先閱讀背面之注意事項再填寫本頁) 經濟部智慧財產局員工消费合作社印製 \ 4277twfLdoc/002 心6954… 五、發明說明（<) density plasma etcher) ’ 並且採用 c4F8/Ar/CO 或者是 C2F6/C4F8/Ar/CO混合氣體作爲蝕刻氣體源。 其中，C4F8氣體流量控制在約1〇至20sccm左右，Ar 氣體流量控制在約100至1〇Osccm左右，以及CO氣體流 量控制在約小於lOOsccm，例如介於〗〜i〇〇sccm之間。若 採用的蝕刻氣體源爲C4F8/C2F6/Ar/CO混合氣體時，其C2F6 與C4F8之流量比値約爲0.5至I.1左右。C2F6與C4F8氣體 可提供高分子反應所需的碳原子與蝕刻反應所需的氟原 子。Ar可增加離子轟擊的能力，以減少高分子沉積在開口 36側壁。而CO則可用來平衡蝕刻反應中沉積在開口 36 底部的高分子數量。 第4圖繪示一種依據本發明較佳實施例一種ICP高密 度電漿蝕刻機台。請參照第4圖，ICP高密度電漿蝕刻機 台之頂端40其溫度控制在約150°C至約300°C左右。基 座42上之套環44其溫度控制在約150°C至約40(TC左右。 反應室48器壁之溫度約爲150〜400°C。反應室壓力則控 制在約4至約50 mTorr左右。偏壓（Bias Power)約控制在 1000watts 至 2000watts 之間。功率約爲 1500watts 至 3000watts左右。冷卻機46之溫度則控制在-20°C至20°C 左右。 於高溫下進行電漿反應係由於反應室中所產生之高分 子的數量一定，而在高溫下高分子不易附著於反應室壁 上，因此在晶片上沈積的分子數目因而增加，而且高溫亦 可使氟離子容易與反應室中的CFXK合物產生反應，如此 (諳it閲讀背is之注意事項再蜞窝本頁) ---I I ---"III — 蝮 經濟部智慧財產局員工消費合作杜印製 1 本紙張尺度適用令國國家標準（CNS>A4規格（210 X 297公》) Α7 Β7 λ ^ 4277twfl.doc/002 ^ ^69 κ ,； 五、發明說明（1) 可減少氟離子的含量，控制其蝕刻反應之速率。因此可使 得提供碳原子的C4F8與C2F6氣體能夠和氧化矽層產生聚 合反應’而在被蝕刻之氧化矽層的蝕刻壁和氮化矽層上沈 積一層高分子薄膜，有助於乾飩刻的非等向性。 其中，沉積在氧化砂層之尚分子可被移除。然而，沉 積在非氧化矽層上的高分子則不容易被移除，這些非氧化 矽層包括氮化矽、矽化鎢、矽化鈦與鋁等。因此，蝕刻步 驟可以利用這些非氧化矽層，例如氮化矽層，作爲蝕刻終 點。 在本發明中控制蝕刻速率之方法包括於蝕刻氣體源中 加入C0氣體以及使用較高的Ar氣體流量(約100~500SCCm 左右）。本發明並且調整C4F8氣體流量、C4F8/C2F6之流量 比、反應室溫度以及其他的操作條件，藉以達到20 : 1的 蝕刻選擇比，且同時形成接近90度(>89度）之接觸窗垂直 輪廓。如此解決了習知技藝無邊界接觸窗製程中選擇蝕刻 選擇比或接觸窗輪廓間的限制。 請參照第3C圖，完成氧化矽層35的蝕刻步驟後，去 除氮化矽層34而暴露出源極/汲極區33以形成接觸窗開 口 36a。之後可以任何習知技藝於接觸窗中塡入多晶矽或 金屬等導電材料，可作爲導線（wiring line)或內連接線 (interconnect)之用，而完成所需的元件結構。 本實施例中之開口係以接觸窗開口爲例，因此在開口 形成後，所暴露出者爲摻雜區。若開口以介層窗開口爲例， 則開口形成後，所暴露出者爲導電層。再者，以金屬鑲嵌 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） 111 )11111 I, 裝· — 1 I 訂- ·,·.^ — ·1··^ (請先閱讀背面之注意事項再填寫本頁) 經濟部智慧財產局員工消費合作社印製 4 泛fl.:dctc：_2 A7 五、發明說明（$ ) 製程爲例，則是暴露出導電層。而本發明均可應用於接觸 窗開口、介層窗開口或是金屬鑲嵌形成的開口等製程當 中。 由上述本發明較佳實施例可知，本發明的特徵在於： 1. 進行接觸窗的蝕刻製程時，採用ICP高密度電漿 蝕刻機並使用C4F8/Ar/CO或者是C4F8/C2F6/Ar/C◦作爲蝕 刻氣體源和控制其操作條件，可同時達到高氧化物對氮化 物的蝕刻選擇比且形成垂直輪廓的接觸窗開口，而不需犧 牲任何一個條件。 2. 本發明採用一種可產生高密度電漿氣體的電感式 耦合電漿蝕刻機，使用C4F8/Ar/CO或者是C4F8/C2F6/Ar/CO 作爲蝕刻氣體源，且在高的反應室溫度下進行接觸窗的触 刻製程。藉由控制高分子的沈積速率，可控制蝕刻時所欲 形成的接觸窗輪廓。 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)I Order Completion This paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm). It is printed by the Ministry of Intellectual Property Bureau's Consumer Cooperatives 4 2 6 ^ 4. · 2 A7 B7 V. Description of the invention (1) Except the silicon nitride layer 14 to expose the source / drain region 13 and complete the process of contact window opening 16a. Please refer to FIGS. 2A to 2D. In the above etching step for the silicon oxide layer, the oxide to nitride selectivity is an important factor affecting the formation of the contour of the contact window 16. Improper etching selection ratio will cause the end of the silicon oxide layer to stop on the silicon nitride layer 14 when the silicon oxide layer is etched, such as the opening 21 formed by over-etching the silicon nitride layer (as shown in FIG. 2A), or the etching is not reached. The end point is the opening 18 (shown in FIG. 2B) formed by stopping the etching, or the tapered opening 19 (shown in FIG. 2C), but it will cause the area of the bottom of the opening to shrink and Causes high contact resistance. However, the conventional technique uses an inappropriate etching selection ratio ′, which makes it difficult to control the end point of etching during the process of etching the oxide, so it is easy to cause the above-mentioned situation, which may cause electrical problems when subsequently filling the conductive layer. If this process requires high selectivity, and if it is to be stopped on the silicon nitride layer, then in the process with a sharp opening at the bottom end, the etching selectivity of the silicon nitride layer cannot be effectively improved. In addition, in order to meet the requirements of the accumulation degree of the components, the industry gradually strives to form a contact window opening with a vertical profile (veriicai prófiie) close to 90 degrees (89 degrees) to meet the requirements of the design rule. However, when the conventional technique forms a vertical contour contact window opening close to 90 degrees, under the above-mentioned conditions, it is easy to deposit a polymer film at the top corners, which affects the anisotropy of the etching and easily forms a round and zigzag contour (b 〇wing pr〇file) open 2 20 (as shown in Figure 2D), which causes the step to cover the warehouse t when the conductive layer is subsequently filled; the poor force causes the generation of voids, resulting in poor component contact 4 This paper size is applicable to China National Standard (CNS) A4 specifications (210 X 297 meters) (please read the unintentional items on the back of β and fill in this page). ------------ Order -------- Aa — ^^ TTtwf). Doc / 0 0 2/17 4 269 5 4 ____B7_____ 5. Description of the invention (7) and other situations. However, in the plasma etching process, a high etching selection ratio and a contact window opening forming a vertical profile often cannot be taken into consideration at the same time. Therefore, the conventional touch-engraving technology of a borderless contact window usually decides one of the conditions as required. 11 The present invention provides A method for manufacturing a high-aspect-ratio element contact window or an interlayer window. The manufacturing method includes using an etching process. The etching process is performed in a reaction chamber. The etching process includes: using a C4F8 / Ar / CO mixed gas or It is a C4F8 / C2F6 / Ar / CO mixed gas as an etching gas source, and controls the C4F8, Ar, and C0 gas flow rates of approximately 10 to 20 seem, 100 to 500 sccm, and 1 to 100 sccm, respectively, and the C2F6 / C4F8 gas flow ratio is approximately 0.5 ~ 1.5, where the reaction chamber includes: wall temperature of about 150 ~ 400 ° C; pressure of about 4mTorr to 100mTorr; Bias Power of about 1000watts to 2000watts: power of about 1500watts to 3000watts; top cover temperature About 150 ° C to 300 ° C; collar temperature is about 150eC to 400.0; and cooler temperature is about -20 ° C to 20 ° C. Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs, the present invention can be formed at a high oxide-to-nitride etching selection ratio. Straight-profile contact window openings without sacrificing any one of the conditions, to avoid g Excessive etching or stopping at the end of the etching will stop etching, such as stomach shape, or the formation of a contact window with a zigzag contour, which will cause component leakage and instability. The present invention provides a method for manufacturing a high-aspect-ratio element contact window >% contact window profile required for control. In order to make the above and other objects, features, and advantages of the present invention comprehensible, a preferred embodiment is given below in conjunction with the accompanying drawings to make _ 5 This paper size applies to the National Standard for Consolidation (CNS) A4 Specifications (210 X 297 mm) 4 2 g9 5 fl.doc / 002 A7 B7 Printed by the Intellectual Property Bureau of the Ministry of Economic Affairs, consumer cooperation Du printed 5. Description of the invention (r) The detailed description is as follows: Brief description of the diagram: Figure 1A FIG. 1 to FIG. 1C are cross-sectional views showing a manufacturing process of a conventional high-aspect-ratio borderless contact window. Figures 2A to 2D show the contours of four high-aspect-ratio borderless contact windows. 3A to 3C are cross-sectional views illustrating a manufacturing process of a high-aspect-ratio non-boundary contact window according to a preferred embodiment of the present invention. FIG. 4 illustrates an ICP high-density plasma etching machine according to a preferred embodiment of the present invention. Description of the drawing symbols: 10, 30: substrate 11, 31: element isolation structure 12, 32: MOS transistor 13, 33: source / drain region 14, 34: nitrided sand layer 15, 35: silicon oxide layer 16 , 16a, 36, 36a: Contact window 40: Top 42: Base 44: Collar 4 6: Cooler 48: Reaction chamber 17: Traditional etching steps This paper size applies Chinese National Standard (CNS) A4 (210 X 297) Mm) ------------- ^ · ---- II Order -------- ^ (谙 Please read the precautions for face-free before filling this page) 4277twfl.doc / 〇〇2 A7 V. Explanation of the invention (Even) 37: Etching steps 18, 19, 20, 21 of the present invention: _ 口 实施 例 3A fflgm 3C: Example of the thin dragon female-a kind of high aspect ratio without border A cross-sectional view of the manufacturing process of a contact window. Referring to FIG. 3A, a substrate 30 is provided first, and an element isolation structure 31 has been formed on the substrate 30. The material is, for example, an oxide, a high-density plasma oxide, a dished glass, or an atmospheric chemical vapor deposition oxide. . A transistor structure or other element structure 32 has been formed on the active region defined by the element isolation structure 31. The transistor structure 32 has a source / drain region 33. Thereafter, a silicon nitride layer 34 is deposited on the substrate 30 surface, for example, by a low pressure chemical vapor deposition method (LPCVD) or an electrical gain chemical vapor deposition method (pECVD) as an end point when defining a contact window. After that, a silicon oxide layer 35 'is formed on the surface of the substrate 30, and the material is, for example, LpCVD oxide, high-density galvanized oxide, phosphate sand glass, atmospheric pressure chemical vapor deposition oxide, or borophosphosilicate glass. The oxidized sand layer 35 needs to have a thicker thickness to completely cover the transistor structure 32 on the substrate 30 and provide an isolation effect. Referring to FIG. 3B, a patterned mask layer (not shown) is formed on the dielectric layer 35 by a lithography process to define a pattern of the contact window opening 36. Next, the etching step 37 of the silicon oxide layer 35 is performed, and the silicon nitride layer 34 is used as an etching stop layer, and the silicon nitride layer 34 is exposed to form an opening 36. Unlike the conventional method, the etching step 37 of the present invention is For example, using an inductively coupled plasma etching machine with high density plasma (ICP high This paper size applies to China National Standard (CNS) A4 specifications (210 X 297 mm) — — — If ----- *- -IIn --- — — — — — (Please read the notes on the back before filling this page) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs \ 4277twfLdoc / 002 Heart 6954… V. Description of the invention (<) density plasma etcher) 'And use c4F8 / Ar / CO or C2F6 / C4F8 / Ar / CO mixed gas as the etching gas source. Among them, the C4F8 gas flow rate is controlled at about 10 to 20 sccm, the Ar gas flow rate is controlled at about 100 to 100 sccm, and the CO gas flow rate is controlled to be less than about 100 sccm, for example, between 0 and 100 sccm. If the etching gas source used is a C4F8 / C2F6 / Ar / CO mixed gas, the flow ratio of C2F6 to C4F8 is about 0.5 to about 1.1. C2F6 and C4F8 gases can provide carbon atoms required for polymer reactions and fluorine atoms required for etching reactions. Ar can increase the ability of ion bombardment to reduce the deposition of polymers on the side walls of the opening 36. CO can be used to balance the amount of polymers deposited on the bottom of the opening 36 during the etching reaction. FIG. 4 illustrates an ICP high-density plasma etching machine according to a preferred embodiment of the present invention. Referring to Fig. 4, the temperature of the top end 40 of the ICP high-density plasma etching machine is controlled at about 150 ° C to about 300 ° C. The temperature of the collar 44 on the base 42 is controlled at about 150 ° C to about 40 ° C. The temperature of the wall of the reaction chamber 48 is about 150 ~ 400 ° C. The pressure of the reaction chamber is controlled at about 4 to about 50 mTorr The bias voltage (Bias Power) is controlled between 1000watts and 2000watts. The power is about 1500watts to 3000watts. The temperature of the cooler 46 is controlled between -20 ° C and 20 ° C. Plasma reaction at high temperature Because the amount of macromolecules generated in the reaction chamber is constant, and the polymer is not easy to adhere to the wall of the reaction chamber at high temperature, the number of molecules deposited on the wafer is increased, and the high temperature can also make fluoride ions easily contact the reaction chamber. CFXK compounds in the reaction, so (谙 it read the precautions on the back of this page and then go to this page) --- II --- " III — 消费 The Intellectual Property Bureau of the Ministry of Economic Affairs, the consumer cooperation of Du Du printed 1 paper Standards apply national standards (CNS > A4 specifications (210 X 297) "Α7 Β7 λ ^ 4277twfl.doc / 002 ^ ^ 69 κ ,; 5. Description of the invention (1) It can reduce the content of fluoride ions and control its etching The rate of the reaction. C4F8 and C2F6 gases can polymerize with the silicon oxide layer to deposit a polymer film on the etched wall of the silicon oxide layer and the silicon nitride layer, which contributes to the anisotropy of dry etching. The molecules deposited on the oxidized sand layer can be removed. However, the polymers deposited on the non-silicon oxide layer cannot be easily removed. These non-silicon oxide layers include silicon nitride, tungsten silicide, titanium silicide, and aluminum. Therefore, the etching step can use these non-silicon oxide layers, such as silicon nitride layers, as the end point of the etching. The method of controlling the etching rate in the present invention includes adding CO gas to the etching gas source and using a higher Ar gas flow rate ( (Approximately 100 ~ 500 SCCm or so). The present invention also adjusts the C4F8 gas flow rate, C4F8 / C2F6 flow rate ratio, reaction chamber temperature, and other operating conditions to achieve an etching selection ratio of 20: 1, and at the same time form close to 90 degrees (> 89 degrees) vertical contour of the contact window. This solves the limitation of the choice of etching selection ratio or contact window contour in the conventional borderless contact window manufacturing process. Please refer to Figure 3C to complete the oxygen After the siliconization layer 35 is etched, the silicon nitride layer 34 is removed to expose the source / drain regions 33 to form a contact window opening 36a. After that, conductive materials such as polycrystalline silicon or metal can be inserted into the contact window by any conventional technique , Can be used as a wiring (wiring line) or interconnect (interconnect) to complete the required element structure. The opening in this embodiment is a contact window opening as an example, so after the opening is formed, the exposed Is a doped region. If the opening is an example of a via of an interlayer window, after the opening is formed, the exposed layer is a conductive layer. In addition, the Chinese national standard (CNS) A4 specification (210 X 297 mm) is applied to the paper inlaid on the metal scale. 111) 11111 I, installed · — 1 I ordered-·, ·. ^ — · 1 ·· ^ (Please Read the notes on the back before filling this page) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 4 Pan fl.:dctc:_2 A7 V. Description of the Invention ($) The process is exposed, for example, and the conductive layer is exposed. The present invention can be applied to processes such as contact window openings, interlayer window openings, or openings formed by metal inlays. As can be known from the above-mentioned preferred embodiments of the present invention, the present invention is characterized by: 1. When performing an etching process of a contact window, an ICP high-density plasma etching machine is used and C4F8 / Ar / CO or C4F8 / C2F6 / Ar / C is used. ◦As an etching gas source and controlling its operating conditions, it can simultaneously achieve a high oxide-to-nitride etching selection ratio and form a vertical profile contact window opening without sacrificing any one condition. 2. The present invention adopts an inductively coupled plasma etching machine capable of generating high density plasma gas, using C4F8 / Ar / CO or C4F8 / C2F6 / Ar / CO as an etching gas source, and at a high reaction chamber temperature Carry out the process of touching the contact window. By controlling the deposition rate of the polymer, the contour of the contact window that is to be formed during etching can be controlled. 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 changes 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. (Please read the notes on the back before filling this page)
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