526555 A7 B7 198twf.d〇c/006 五、發明說明（丨） 本發明是有關於一種半導體製程，且特別是有關於 一種低介電常數材料層的蝕刻方法。 介電材料(dielectric material)在VLSI製程裡，通常被 用來作爲元件中各導體層之間的內介電層（inter layer)。 爲了降低訊號傳遞時間延遲，目前的趨勢是傾向使用較低 介電常數的材料來作爲內介電層。這些低介電常數材料大 部份都含有機的成份在其中，常見的含有機成份之低介電 常數材料包括無機低介電材料以及有機聚合物（organic： polymer)，無機低介電材料例如Si〇2-CH3與Si(CH3)4等； 而有機聚合物則例如有F1ARE和SILK等。 無機介電材料中’以Si-CH3(methylsilane)作爲前驅物 (precusor)而形成的無機介電材料，其成分中含有carb〇nyl 官能基’有助於降低介電常數。 習知蝕刻上述無機介電材料係使用C4F8、C〇、Ar與 〇2的混合氣體作爲軸刻氣體’然而，利用此蝕刻氣體並不 容易進行含有有機成分之介電材料的蝕刻步驟。其困難之 處在於适些蝕刻氣體中C1 2F8氣體提供了高分子反應的施體 (d〇n〇r)，再加t無機介電材料中含有carbonyl官能基，如 此很谷易發生咼分子反應，而於開口側壁產生高分子聚合 物’姐成蝕刻的困難’甚至發生未達蝕終點就停止触刻 的情形，如第1圖所示。 而且，由於習嫌卿體容^產生高分子反 應，而累積在所形成的開口側壁上，不易控制触刻的開口 輪廓（profile)，導致開口的形成輪廓不理想，影響後續的 —-----------^^^裝--------訂---------線 2晴先閱讀背面之注音？事項再填寫本頁> 經濟部智慧財產局員工消費合作社印製 1 2 本紙張尺度適用中國國家標準（CNS)A4規格（210 X ----526555 A7 B7 198twf.doc / 006 V. Description of the Invention (丨) The present invention relates to a semiconductor process, and in particular, to a method for etching a low dielectric constant material layer. Dielectric materials are commonly used in VLSI processes as inter layers between conductor layers in a device. In order to reduce the signal transmission time delay, the current tendency is to use a material with a lower dielectric constant as the internal dielectric layer. Most of these low dielectric constant materials contain organic ingredients. Common low dielectric constant materials containing organic ingredients include inorganic low dielectric materials and organic polymers (organic: polymers). Inorganic low dielectric materials such as Si02-CH3, Si (CH3) 4, etc .; and organic polymers include F1ARE and SILK. Among the inorganic dielectric materials, an inorganic dielectric material formed using Si-CH3 (methylsilane) as a precursor has a carbonyl functional group in its composition to help reduce the dielectric constant. It is conventionally known that the above-mentioned inorganic dielectric material uses a mixed gas of C4F8, Co, Ar, and O2 as the axis-etching gas'. However, it is not easy to perform an etching step of a dielectric material containing an organic component by using this etching gas. The difficulty lies in that the C1 2F8 gas in the etching gas provides the donor (donor) of the polymer reaction, and the inorganic dielectric material contains the carbonyl functional group, so it is very prone to fluorene molecular reactions. However, the high polymer “difficulty in forming an etching” is generated on the side wall of the opening, and even if the end of the etching is not reached, the etching is stopped, as shown in FIG. 1. In addition, because Xi Suqing's body mass has a polymer reaction and accumulates on the side wall of the formed opening, it is difficult to control the profile of the opening that is engraved, resulting in an unsatisfactory contour of the opening, which affects the subsequent ----- -------- ^^^ Equipment -------- Order --------- Line 2 Qing first read the phonetic on the back? Please fill out this page again for the matter> Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 1 2 This paper size is applicable to China National Standard (CNS) A4 (210 X ----
526555 5 1 98twf.doc/〇〇6 五、發明說明（汉） 製程。 因此，本發明的目的就阜女w /XL 數材料層_難法，可以_^;^種雜低介電常 生的_，懸介電雖時所產 。丨…、則史1宁止蝕刻的情形。 本發明的另一目的是在棵住:一 $ 料層的麵旅，购m常數材 勿ί工制蝕4後所形成的開口輪廓。 根據本發明之上述目的，桿屮 @ ^ J 出一種無機低介電常數 材麵的顯方法，其_方法驗用包括W、關Ar 之混合氣讎麵__，其㈣龍合_中N2具 有去聚合隱力，職少ill賴分子的雜，如此可容易 控制蝕刻後所形成的開口輪廓。 此外，本發明亦提供一種開口的形成方法，其方法 包括於半導體基底上形成一無機低介電常數材料層，於無 機低介電常數材料層上，形成一已圖案化罩幕層，接著， 進行一蝕刻步驟，於無機低介電常數材料層中形成一開 口，其中此I虫刻步驟係使用包括C4F8、N2與Ar之一混合 氣體作爲蝕刻氣體源。 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： 第1圖繪示利用習知蝕刻方法所形成的開口；以及 第2A至2C圖繪示依照本發明一較佳實施例的一種 開口的製程剖面圖。 圖式之簡單說明： 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） ------------裝--------訂---------線 (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 經濟部智慧財產局員工消費合作社印製 526555 5 1 98twf.doc/〇〇6 A7 _________ B7 五、發明說明（j) 200 :基底 202 :'導體層 204 :無機低介電常數材料層， 206 :罩幕層 2〇8 :聞.p 竇施例 習知無機低介電常數材料層的蝕刻方法係採用的蝕 刻氣體’容易於蝕刻的過程中發生高分子聚合反應，再加 上無機低介電材料中含有carb〇nyi官能基，更易於開口的 ί則壁生成高分子，造成開口未達蝕刻終點就停止蝕刻的情 形°而且因爲高分子容易累積在開口側壁，導致開口的形 成輪廓不容易控制，因此本發明提出一種無機低介電常數 材料層的蝕刻方法，藉由改變蝕刻的電漿氣體源，以解決 無機低介電材料中因含有有機成分，所造成蝕刻發生的困 難，藉以改善開口的形成輪廓。 爲了詳細說明本發明的蝕刻方法，以下特別以於無 機低介電常數材料層中形成開口的製程作爲一較佳實施 例’以使本發明之特徵和優點能更淸楚易懂。 第2A至2C圖繪示依照本發明一較佳實施例的一種 開口的製程剖面圖。 請參照第2A圖，首先，提供一半導體基底200，於 基底200上，形成一導體層202。 請參照第2B圖，於導體層202上，形成一材料層204， 此材料層204較佳爲具有低介電常數之無機材料層。接著， 5 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公爱） ------------裝--------訂---------線 (請先閱讀背面之注意事項再填寫本頁) 5 5 5 6 2 5 五 經濟部智慧財產局員工消費合作社印製 5 198twf.doc/006 、發明說明（斗） 於無機低^電常數材料層2〇4上，形成一圖案化之罩幕層 206，此罩幕層例如爲光阻。 ” 師篸k第2C圖，以此罩幕層2〇6爲蝕刻罩幕，對材 料層204進行一蝕刻步驟，於無機低介電常數材料層2〇4 中形成一開口 208，暴露出導體層202。此蝕刻步驟係使 用包括C/s、N2與Αι·的混合氣體作爲蝕刻氣體源，其中 混合氣體中QF8的氣體流速約爲5_2〇sccm，队的氣體流速 約爲20-300sccm ’ Ar的氣體流速約爲1〇〇_4〇〇sccin，壓力 約爲20-60 mtoir，溫度約爲攝氏_1〇-5〇度。 此外，在蝕刻材料層204的過程中，還包括一冷卻步 驟’用以冷卻晶片。此冷卻步驟是利用He氣體來冷卻， 其使用的壓力例如約7-20 ton*。 、 此蝕刻步驟所使用的蝕刻混合氣體含有氮氣，在本 發明中，氮氣具有去聚合（dep〇iymer)的能力，可在鈾刻無 機低介電材料時減少高分子的生成，提供更佳的鈾刻能 力，避免習知未達蝕刻終點便停止鈾刻的情形發生，解決 蝕刻無機低介電常數材料層的困難。 由於本發明使用氮氣作爲鈾刻混合氣體之一，其可 去聚合（depolymer)，能夠降低高分子的生成反應，減少側 壁高分子的形成，因此更容易控制蝕刻無機低介電材料層 所形成的開口輪廓，而形成具有更直的開口輪廓之開口。 本發明當有其他優點、目的及特徵，顯示於上文和 後述之專利申請範圍之中，或是在實施本發明的過程中顯 示出來。 本紙張尺度適用中國國家標準（CNS)A4規格（21〇 X 297公釐） ^裝--------訂---------線| (請先閱讀背面之注意事項再填寫本頁) 526555 A7 5 198twf.doc/006 _B7 五、發明說明（g ) 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) 經濟部智慧財產局員工消費合作社印製 7 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐）526555 5 1 98twf.doc / 〇〇6 5. Description of invention (Chinese) Process. Therefore, the purpose of the present invention is to make it difficult for the w / XL number material layer of the Fu Nu, which can be _ ^; ^ a variety of hetero-low dielectric constant _, although the suspension dielectric is produced.丨 ..., then Shi 1 would rather stop etching. Another object of the present invention is to purchase the m-constant material at the surface of the material layer, and not to open the contour formed by the etching process. According to the above-mentioned object of the present invention, the rod 显 @ ^ J has developed an explicit method for the surface of inorganic low dielectric constant material. It has the ability to de-aggregate, and it depends on the miscellaneous molecules, so the contour of the opening formed after etching can be easily controlled. In addition, the present invention also provides a method for forming an opening. The method includes forming an inorganic low dielectric constant material layer on a semiconductor substrate, forming a patterned mask layer on the inorganic low dielectric constant material layer, and then, An etching step is performed to form an opening in the inorganic low-dielectric-constant material layer. The I-etching step uses a mixed gas including one of C4F8, N2, and Ar as an etching gas source. In order to make the above-mentioned objects, features, and advantages of the present invention more comprehensible, a preferred embodiment is given below, and it is described in detail with the accompanying drawings as follows: FIG. 1 illustrates a conventional etching method. The formed openings; and FIGS. 2A to 2C show cross-sectional views of a process of an opening according to a preferred embodiment of the present invention. Brief description of the drawing: This paper size is applicable to China National Standard (CNS) A4 specification (210 X 297 mm) ------------ Installation -------- Order --- ------ line (Please read the notes on the back before filling out this page) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs Printed by the Employee Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 526555 5 1 98twf.doc / 〇〇6 A7 _________ B7 V. Description of the invention (j) 200: substrate 202: 'conductor layer 204: inorganic low-dielectric constant material layer, 206: cover layer 208: scent. P. Example of the sinus. Known inorganic low dielectric constant The etching method of the material layer is based on the use of an etching gas that is prone to polymer polymerization during the etching process. In addition, the inorganic low-dielectric material contains carbonyi functional groups, which makes it easier to open the wall. Causes the opening to stop etching before the end of the etching °, and because the polymer easily accumulates on the side wall of the opening, the formation contour of the opening is not easy to control. Therefore, the present invention proposes an etching method for an inorganic low dielectric constant material layer by changing Etched plasma gas source to address inorganic low Dielectric materials contain organic components, making it difficult for etching to improve the contours of the openings. In order to explain the etching method of the present invention in detail, a process of forming an opening in an inorganic low-dielectric constant material layer is taken as a preferred embodiment hereinafter to make the features and advantages of the present invention more understandable. Figures 2A to 2C are cross-sectional views of a process of an opening according to a preferred embodiment of the present invention. Referring to FIG. 2A, first, a semiconductor substrate 200 is provided, and a conductive layer 202 is formed on the substrate 200. Referring to FIG. 2B, a material layer 204 is formed on the conductor layer 202. The material layer 204 is preferably an inorganic material layer having a low dielectric constant. Then, 5 paper sizes are applicable to China National Standard (CNS) A4 specifications (210 X 297 public love) ------------ installation -------- order ------ --- line (please read the notes on the back before filling this page) 5 5 5 6 2 5 5 Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 5 198twf.doc / 006, the invention description (bucket) is low in inorganic ^ A patterned mask layer 206 is formed on the dielectric constant material layer 204, and the mask layer is, for example, a photoresist. Figure 2C, using the mask layer 20 as an etching mask, an etching step is performed on the material layer 204 to form an opening 208 in the inorganic low dielectric constant material layer 204, exposing the conductor. Layer 202. This etching step uses a mixed gas including C / s, N2, and Al as the etching gas source, where the gas flow rate of QF8 in the mixed gas is about 5_2 sccm, and the gas flow rate of the team is about 20-300 sccm 'Ar The gas flow rate is about 100-400 sccin, the pressure is about 20-60 mtoir, and the temperature is about 10-10 degrees Celsius. In addition, in the process of etching the material layer 204, a cooling step is also included. 'It is used to cool the wafer. This cooling step uses He gas to cool, and the pressure used is, for example, about 7-20 ton *. The etching mixed gas used in this etching step contains nitrogen. In the present invention, nitrogen has depolymerization. (Dep〇iymer) ability, can reduce the formation of high-molecular polymers when uranium etched inorganic low-dielectric materials, provide better uranium engraving ability, avoid the situation where the uranium etch is stopped before reaching the end of the etch, and solve the etch inorganic Difficulties in Low Dielectric Constant Material Layers Since the present invention uses nitrogen as one of the uranium-etched mixed gases, it can be depolymerized, which can reduce the formation reaction of polymers and reduce the formation of sidewall polymers, so it is easier to control the formation of the etching of the inorganic low-dielectric material layer. The present invention has other advantages, objects, and features, which are shown in the scope of the above and subsequent patent applications, or are shown in the process of implementing the present invention. . This paper size is applicable to China National Standard (CNS) A4 (21〇X 297mm) ^ Packing -------- Order --------- Line | (Please read the note on the back first Please fill in this page again for details) 526555 A7 5 198twf.doc / 006 _B7 V. Description of the Invention (g) Although the present invention has been disclosed as above with a preferred embodiment, it is not intended to limit the present invention. Anyone skilled in this art, Various changes and modifications can be made without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope of the attached patent application. (Please read the notes on the back before filling out Page) Ministry of Economic Affairs Intellectual Property Office employees consumer cooperatives printed paper 7 scale applicable to Chinese National Standard (CNS) A4 size (210 X 297 mm)