經濟部中央標準局員工消費合作社印製 A7 B7 五、發明説明（(） 發明背景： 發明技術領域： 本發明是關於一種微影蝕刻鋁銅線的方法，特別是關 於一種具有優越的臨界尺寸控制，且會在積體電路製造中 形成傾斜式輪廓鋁銅線的鋁銅線微影蝕刻方法。 先前技術的描述： 由於光阻的蝕刻選擇性較差，在鋁銅蝕刻中常需要厚 的光阻光罩。因此，微影程序中的聚焦深度就變成更具挑 戰性。傳統上，氮化鈦(TiN)層是沉積在鋁銅(AlCu)層上， 當作阻擋層和反反射塗佈層(BARC)。傳統的蝕刻氣體是氯 化硼(BCh)和氯氣(Cl2)。這些氣體已經被發現不足以在鋁 銅線側壁產生足夠的聚合物，來避免蝕刻中過度侵蝕的情 形。美國專利4, 915, 779號(Motorola)在鋁銅上使用一個 保護氧化層，並在真空下同時蝕刻氧化層和鋁銅層。Wei 等的美國專利5, 449, 639號教導了當触刻下層金屬層時， 使用一種可以任意處置的TiN反反射層塗佈於其下面的金 屬上。Wang等的美國專利4, 412, 885號展示一種用含有氧 氣和fluorocarbon攙雜氣體的BC13和Ch來触刻鋁層的方 法。Mizutani等的美國專利4, 511，429號教導使用含氫氣 體的乾蝕刻鋁的方法。Bredbenner·等的美國專利 4, 919, 748號展示使用氯氣和trif luoromethane來作金屬 傾斜蝕刻的方法。 發明簡要說明： 本發明的主要目的是提供一種有效且非常可用於製造 2 (請先閱讀背面之注意事項再填寫本頁)Printed by the Consumers' Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs A7 B7 V. Description of the invention (() Background of the invention: Field of the invention: The present invention relates to a method for lithographic etching of aluminum and copper wires, in particular to a method with superior critical dimension control Aluminium-copper wire lithographic etching method that will form inclined contour aluminum-copper wires in the fabrication of integrated circuits. Description of the prior art: Due to the poor etching selectivity of photoresist, thick photoresist is often required in aluminum-copper etching. Therefore, the depth of focus in the lithography process becomes more challenging. Traditionally, a titanium nitride (TiN) layer is deposited on an aluminum copper (AlCu) layer as a barrier layer and a reflective coating BARC). The traditional etching gases are boron chloride (BCh) and chlorine (Cl2). These gases have been found to be insufficient to produce enough polymer on the side of the aluminum copper wire to avoid excessive erosion during etching. US Patent 4 No. 915, 779 (Motorola) uses a protective oxide layer on aluminum and copper, and simultaneously etches the oxide layer and the aluminum-copper layer under vacuum. US Patent No. 5,449,639 of Wei et al. Teaches when the lower metal layer is touched. In this case, a TiN anti-reflective layer that can be disposed at will be applied to the underlying metal. U.S. Patent No. 4,412,885 to Wang et al. Shows a method of etching the aluminum layer with BC13 and Ch containing oxygen and fluorocarbon doped gases. U.S. Patent No. 4,511,429 by Mizutani et al. Teaches a method of dry etching aluminum using a hydrogen-containing gas. U.S. Patent No. 4,919,748 by Bredbenner et al. Shows the use of chlorine gas and trif luoromethane for oblique etching of metals. Method Brief description of the invention: The main purpose of the present invention is to provide an effective and very useful for manufacturing 2 (Please read the notes on the back before filling this page)
、1T 線、 本紙張尺度適用中國國家標準（CNS ) A4規格（210X297公釐） 137___ 137___ 經濟部十央操隼局員工消費合作社印製 A7 五、發明説明（> ) 之蝕刻鋁銅(AlCu)和鋁矽銅(AlSiCu)線的方法。 本發明的另一目的是提供一種蝕刻鋁銅和鋁矽銅線的 方法，其中微影聚焦深度不是一個問題。 本發明的又一目的是提供一種蝕刻鋁銅和鋁矽銅線的 方法，其中沒有鋁銅和鋁矽銅線的過度侵蝕 (undercutting) ° 本發明的再一目的是提供一種蝕刻鋁銅和鋁矽銅線的 方法，其中一種傾斜式的鋁銅和鋁矽銅線輪廓被完成。 根據本發明的這些目的，一種蝕刻鋁銅和鋁矽銅線的 新方法被完成。半導體元件結構被提供於半導體基板上。 這些半導體元件結構被覆蓋一個絕緣層。 一層鋁銅和鋁矽銅被覆蓋於絕緣層上。一層氮化矽 (SiN)或氮化鈦/二氧化矽(TiN/Si〇2)被覆蓋於金屬層上，其 中一個硬式光罩形成。硬式光罩被覆蓋一層要用化學線作 用光作曝光的光阻，其中硬式光罩可以避免化學線作用光 從它的表面反射。光阻被顯影而開出圚案，形成想要的光 阻光罩。 ^ 沒有被光阻光罩覆蓋的硬式光罩被蝕刻掉，剩下有圓 案的硬式光罩。鋁銅或鋁矽銅和阻擋層中沒有被具有圖案 之硬式光罩覆蓋的部分會被蝕刻掉，形成了具有向外傾斜 輪廓的金屬線。 圖示的簡要說明： 圖1-6以圖式方式舉例了本發明之較佳具體實施例的截面 示意圖。 ____ 3 本&張尺度適用中國國家標準（CNS ) A4規格（210X297公f ) ~ ' (請先閲讀背面之注意事項再填寫本頁) 、·ιτ 線、 ί A7 五、發明説明（3) 經濟部中央標準局員工消費合作社印製 圖5A和5B以圖式方式舉例了本發明之較佳具體實施例的 兩種方法之截面示意圖。 圖號的簡要說明： 10半導體基板 12場氧化層區 14閘極電極 16源極和洩極區 18氧化矽或硼磷矽化物玻璃(BPSG)或相似的厚絕緣層 20阻擋層 22金屬層 24硬式光罩 26光阻光罩 28聚合物 30絕緣層 較佳具體實施例說明： 根據圖1，舉例了一個部份完成的積體電路之一部份。 半導體基板10由單晶組成。場氧化層區域12已經形成於 基板中，如同傳統技術。半導體元件結構製造於半導體基 板上面和內部，包括閜電極U和源極洩極區16。一個厚 的氧化矽(Si〇2)或硼磷玻璃(BPSG)或相似的絕緣層18以地 毯式沉積於半導體體元件結構上。接著，一個阻檔層20沉 積於絕緣層上。這阻擋層可能是鈦(Ti)和氮化鈦(TiN)結合 成厚約500〜1500埃。 根據圖2，金屬層22沉積於阻擋層20上。金屬層由 4 (請先閱讀背面之注意事項再填寫本頁), 1T line, This paper size applies Chinese National Standard (CNS) A4 specification (210X297 mm) 137___ 137___ Printed by A7, Consumer Cooperative of Shiyang Operation Bureau of the Ministry of Economic Affairs 5. Etching Aluminum Copper (AlCu) ) And aluminum-silicon-copper (AlSiCu) wires. Another object of the present invention is to provide a method for etching aluminum-copper and aluminum-silicon-copper wires, in which the depth of lithography focus is not a problem. Another object of the present invention is to provide a method for etching aluminum copper and aluminum-silicon-copper wires, wherein there is no overcutting of aluminum copper and aluminum-silicon-copper wires. Yet another object of the present invention is to provide an etching of aluminum copper and aluminum The method of silicon copper wire, in which an inclined aluminum copper and aluminum silicon copper wire profile is completed. According to these objects of the present invention, a new method for etching aluminum copper and aluminum silicon copper wires is accomplished. The semiconductor element structure is provided on a semiconductor substrate. These semiconductor element structures are covered with an insulating layer. A layer of aluminum copper and aluminum silicon copper is covered on the insulation layer. A layer of silicon nitride (SiN) or titanium nitride / silicon dioxide (TiN / SiO2) is covered on the metal layer, and a hard mask is formed. The hard mask is covered with a photoresist to be exposed by chemical rays as light. The hard mask can prevent chemical rays from reflecting off its surface. The photoresist is developed and opened to form a desired photoresist mask. ^ The hard mask that is not covered by the photoresist is etched away, leaving the hard mask with a circular pattern. The portions of the aluminum copper or aluminum silicon copper and the barrier layer that are not covered by the patterned hard mask are etched away, forming a metal wire with an outwardly inclined profile. Brief description of the figures: Figures 1-6 illustrate the schematic cross-sectional views of a preferred embodiment of the present invention in a diagrammatic manner. ____ 3 This & Zhang scale is applicable to China National Standard (CNS) A4 specification (210X297 male f) ~ '(Please read the precautions on the back before filling this page), · ιτ line, ί A7 V. Description of the invention (3) 5A and 5B printed by the Consumer Standards Cooperative of the Central Standards Bureau of the Ministry of Economics illustrate the cross-sectional schematic diagrams of the two methods of the preferred embodiment of the present invention in a diagrammatic manner. Brief description of drawing number: 10 semiconductor substrate 12 field oxide layer region 14 gate electrode 16 source and drain region 18 silicon oxide or borophosphosilicate glass (BPSG) or similar thick insulating layer 20 barrier layer 22 metal layer 24 The preferred embodiment of the hard mask 26, the photoresist 28, and the polymer 30 insulating layer is described as follows: According to FIG. 1, a part of a partially completed integrated circuit is exemplified. The semiconductor substrate 10 is composed of a single crystal. The field oxide region 12 has been formed in the substrate, as in the conventional technique. The semiconductor element structure is fabricated on and inside the semiconductor substrate and includes a ytterbium electrode U and a source drain region 16. A thick silicon oxide (SiO2) or borophosphoglass (BPSG) or similar insulating layer 18 is deposited on the semiconductor element structure in a blanket manner. Next, a barrier layer 20 is deposited on the insulating layer. The barrier layer may be a combination of titanium (Ti) and titanium nitride (TiN) to a thickness of about 500 to 1500 angstroms. According to FIG. 2, a metal layer 22 is deposited on the barrier layer 20. The metal layer consists of 4 (Please read the precautions on the back before filling this page)
、aT 本紙張尺度適用中國國家標準（CNS ) A4規格（210X29?公釐） B7 B7 經濟部中央標隼局員工消費合作社印製 五、發明説明（4) 鋁銅(AlCu)或鋁矽銅（AlSiCu)組成.，用濺鍍方式沉積，厚 約4000〜8000埃。 接著，形成本發明的硬式光罩。參考圖3，一層氮化 矽(SiN)或多層氮化鈦(TiN)和氧化矽(Si〇2)24沉積於金屬 層22上，厚約2QG0〜4GGG埃，形成硬式光罩。硬式光罩 對於微影中的化學線作用光是不透明的，所以光不會從它 反射。硬式光罩也扮演反反射層。 一層光阻塗佈於硬式光罩24上，然後經曝光顯影形成 光阻光罩26。在本發明的製程中，光阻的厚度約7000〜 14000埃。傳統上，光阻厚度約12〇(Κ)〜18000埃。本發明 的較薄光阻層，在形成光阻光罩的微影中，並沒有造成聚 焦深度的問題。使用DUV微影代替1-1 ine微影允許較薄的 光阻層。 如圖4，氮化矽(SiN)層中沒有被光阻光罩覆蓋的部份 被蝕刻掉。氮化矽的蝕刻使用高氮化矽蝕刻率的配方，譬 如SFe/HBr/He或CF4/Ar。這些蝕刻配方包括高氟原子電 漿’可以保持接近垂直的氮化矽(SiN)外型和優越的臨界尺 寸控制。譬如，使用CF4/Ar，氣體以50sccm的CF4和500sccin 的Ar流動。射頻頻率保持約13〇()瓦，壓力約15〇mTorr^ 尚速流動的Ar允許低濃度的fluorine radicals，可避免 氮化矽側壁的過度侵蝕。高的射頻頻率功率亦可幫助方向 性蝕刻。 光阻光罩26可以用傳統的方法移去，譬如oxygen ashing。另一種選擇是光阻可以留到金屬線被蝕刻出來之 5 本紙張尺度適用中國國家標準（CNS ) A4規格（210X297公釐） (請先閱讀背面之注意事項再填寫本頁)、 AT This paper size applies to Chinese National Standard (CNS) A4 specification (210X29? Mm) B7 B7 Printed by the Consumer Cooperatives of the Central Bureau of Standards of the Ministry of Economic Affairs 5. Description of the invention (4) Aluminum copper (AlCu) or aluminum silicon copper ( AlSiCu), deposited by sputtering, with a thickness of about 4000 ~ 8000 angstroms. Next, a hard mask of the present invention is formed. Referring to FIG. 3, a layer of silicon nitride (SiN) or multiple layers of titanium nitride (TiN) and silicon oxide (SiO2) 24 is deposited on the metal layer 22 to a thickness of about 2QG0 to 4GGG, forming a hard mask. The hard mask is opaque to chemically-acted light in lithography, so light is not reflected from it. The hard mask also acts as a retroreflective layer. A layer of photoresist is coated on the hard mask 24, and then developed by exposure to form a photoresist mask 26. In the process of the present invention, the thickness of the photoresist is about 7000 to 14000 angstroms. Traditionally, the photoresist has a thickness of about 120 (K) to 18,000 angstroms. The thin photoresist layer of the present invention does not cause a problem of the depth of focus in the lithography forming the photoresist mask. Using DUV lithography instead of 1-1 ine lithography allows for thinner photoresist layers. As shown in Figure 4, the portion of the silicon nitride (SiN) layer that is not covered by the photoresist mask is etched away. Silicon nitride is etched using a high silicon nitride etching rate formula, such as SFe / HBr / He or CF4 / Ar. These etch recipes include high-fluorine atomic plasma ’which maintains a nearly vertical silicon nitride (SiN) profile and superior critical size control. For example, using CF4 / Ar, the gas flows at 50 sccm CF4 and 500 sccin Ar. The RF frequency is maintained at about 13 watts, and the pressure is about 15 mTorr ^ The fast flowing Ar allows low concentrations of fluoride radicals, which can avoid excessive erosion of the silicon nitride sidewall. High RF frequency power also helps directional etching. The photoresist mask 26 can be removed by conventional methods, such as oxygen ashing. Another option is that the photoresist can be left until the metal wire is etched. 5 This paper size applies to China National Standard (CNS) A4 (210X297 mm) (Please read the precautions on the back before filling this page)
I 經濟部中央標隼局員工消費合作社印製 五、發明説明（<) 後才移去。如果在金屬蝕刻中，氮化矽的損失可以維持在 最小保留厚度(典型值約500埃)之上，則光阻可以在金屬 蝕刻前移去。如果氮化矽的損失太高，則光阻應該先保留 成光罩的一部份。 現在，金屬層和下面的阻擋層20中，蝕刻去除掉未被 硬式光罩覆蓋的部份，留下金屬線，如圖5A和5B，一個 有向外傾斜的外形之金屬線，有好的側面保護層是較佳 的。一層聚合物28在蝕刻時形成於金屬線的側面，用以提 供側面保護。聚合物避免金屬線在蝕刻中或蝕刻後受到氯 蝕(chlorine radicals)即所謂的侵蝕現象。 傾斜的金屬線外形的完成是在蝕刻時，增加操作壓力 和加入保護氣體，譬如CH4或CHF3。蝕刻配方的總氣體留量 是300〜700sccm，其中製程氣體Ar占15%〜45%，CH4或 CHF3 占 1%〜10% ’ BCh 占 20%，Cl2 占 50%，在 1. 5 〜 8pascals 下，大約 11 〜62mTorr。 圖5A和5B列舉出有向外傾斜外形的金屬線22。圖5A 舉出一種方法：讓光阻光罩在蝕刻中仍留在硬式光罩上。 圖5B舉出另一種方法，讓光阻光罩在金屬鈾刻前就已經移 去。如果光阻光罩26尙未移去，那就現在移去。聚合物的 移去可以用oxygen ashing和濕化學剝落。參考圖6，一 個絕緣層30，如氧化矽(Si〇2)或氮化矽(SiN)或相似物，沉 積於金屬線22上。因爲金屬線的傾斜外形，可以避免金屬 線間的溝帶形成孔洞。 本發明的製程使用一個氮化矽(SiN)或氮化鈦/氧化矽 6 本紙張尺度適用中國國家標準（CNS ) A4規格（210X297公釐） — — (請先閲讀背面之注意事項存填疼本頁) 訂 气， A7 ___ 五、發明説明（4) (TiN/Si〇2)硬式光罩。本發明允許較薄的光阻層，在形成硬 式光罩時’避免聚焦深度的問題。用來形成硬式光罩的蝕 刻配方已經被發展且實驗性的用來提供硬式光罩接近垂直 的外形，使它有優越的臨界尺寸控制。本發明的蝕刻配方， 對於蝕刻的金屬線，提供了向外傾斜的外形，且沒有過度 侵蝕。 當本發明以參考較佳的具體實施例作特別的描述，它 將被熟知此技術的人士所了解，任何針對本發明作形式上 和細部上的各種改變，都無法脫離本發明的精神與範圍。 ^ οΪΤXL/ (請先閱讀背面之注意事項再填寫本頁) 經濟部中央樣準局員工消费合作社印製 本紙張尺度適用中國國家標準（CNS ) Μ規格（210X297公釐）I Printed by the Consumer Cooperatives of the Central Bureau of Standards of the Ministry of Economic Affairs 5. The invention description (<) was removed. If the loss of silicon nitride can be maintained above the minimum remaining thickness (typically about 500 angstroms) during metal etching, the photoresist can be removed before the metal etching. If the loss of silicon nitride is too high, the photoresist should be retained as part of the mask first. Now, in the metal layer and the lower barrier layer 20, the portion not covered by the hard mask is etched away, leaving metal lines, as shown in Figures 5A and 5B. A metal line with an outwardly inclined shape has a good A side protective layer is preferred. A layer of polymer 28 is formed on the sides of the metal lines during etching to provide side protection. The polymer protects the metal wire from chloride radicals during or after etching, a phenomenon called erosion. The profile of the slanted metal wire is completed by increasing the operating pressure and adding a protective gas such as CH4 or CHF3 during etching. The total gas retention of the etching recipe is 300 ~ 700sccm, in which the process gas Ar accounts for 15% ~ 45%, CH4 or CHF3 accounts for 1% ~ 10% 'BCh accounts for 20%, and Cl2 accounts for 50%, at 1.5 to 8pascals under , About 11 ~ 62mTorr. 5A and 5B list metal wires 22 having an outwardly inclined profile. FIG. 5A illustrates a method in which a photoresist mask remains on a hard mask during etching. Fig. 5B illustrates another method in which the photoresist mask is removed before the metal uranium is etched. If the photoresist mask 26 尙 has not been removed, remove it now. Removal of the polymer can be achieved by oxygen ashing and wet chemical exfoliation. Referring to FIG. 6, an insulating layer 30, such as silicon oxide (SiO2) or silicon nitride (SiN) or the like, is deposited on the metal line 22. Due to the slanted shape of the metal wires, the grooves between the metal wires can be prevented from forming holes. The process of the present invention uses a silicon nitride (SiN) or titanium nitride / silicon oxide. 6 The paper size is applicable to the Chinese National Standard (CNS) A4 specification (210X297 mm) — — (Please read the precautions on the back first and fill in the pain. (This page) Ordering, A7 ___ V. Description of the invention (4) (TiN / Si〇2) rigid photomask. The present invention allows a thinner photoresist layer to avoid the problem of depth of focus when forming a hard mask. Etching formulations used to form hard masks have been developed and experimentally used to provide a hard mask with a nearly vertical profile, giving it superior control of critical dimensions. The etching formulation of the present invention provides an outwardly inclined shape for the etched metal lines without excessive erosion. When the present invention is specifically described with reference to the preferred embodiments, it will be understood by those skilled in the art. Any changes in form and detail to the present invention can not depart from the spirit and scope of the present invention. . ^ οΪΤXL / (Please read the notes on the back before filling out this page) Printed by the Employees' Cooperatives of the Central Sample Bureau of the Ministry of Economic Affairs This paper applies the Chinese National Standard (CNS) M specifications (210X297 mm)