200402804 五、發明說明（1) 本案是有關於一種金屬圖案方法，藉由一沉積步驟將 其中至少一種腐餘強烈的金屬層沉積在一石夕基質上，然 後，經由使用一光阻的光微影圖案方法在該腐蝕強烈的 金屬層上產生一#刻遮罩，接著利用I虫刻將該金屬層圖 案在I虫刻遮罩中。 在半導體工業上習用的金屬蝕刻需要使用適合的光阻 光罩，此形式的光阻光罩定義#刻進行的結構，例如， 金屬結構的空間邊界。為此目的，首先提供一光阻層塗 至基層上，然後利用標準的光微影圖樣方法圖案化一光 阻遮罩（例如，深紫外光（DUV)、i-1 ine等）。為了達到特 別小的圖案大小，因而使用一種 w/光阻遮罩，適合用 在雷射直接刻寫系統（laser direct writing system)或 者是電子束微影。所述的光阻遮罩因為其作用，然後被 用來圖案位於該光阻遮罩之下的功能層，在預備的製程 步驟中已經被塗覆至一基質的此類型功能層可能是摻雜 或是為摻雜的多晶矽層、二氧化矽層、金屬層以及可能 需要的另外的功能層。 在I虫刻操作期間，所實行的是，例如，藉由在適合的 大氣中的電漿蝕刻，然而，缺乏足夠選擇性其意為其不 可能避免該蝕刻遮罩的腐蝕。 假如實行一金屬餘刻，例如，在一銘層或是銅铭層’ 在蝕刻操作期間，必須同時確認已經被蝕刻結構的充足 鈍化。在蝕刻操作期間會形成副產品，特別是碳化合 物，可使在已經蝕刻的金屬結構中達到側壁的鈍化。此200402804 V. Description of the invention (1) This case relates to a metal pattern method, in which at least one strongly corroded metal layer is deposited on a stone matrix by a deposition step, and then, by a photolithography using a photoresist The patterning method generates a # engraved mask on the strongly corroded metal layer, and then uses the I engraving to pattern the metal layer in the I engraved mask. The conventional metal etching in the semiconductor industry requires the use of a suitable photoresist mask. This form of photoresist mask defines the structure that is performed at the moment, for example, the spatial boundary of the metal structure. For this purpose, a photoresist layer is first applied to the base layer, and then a photoresist mask (for example, deep ultraviolet (DUV), i-1 ine, etc.) is patterned using a standard photolithography method. In order to achieve a particularly small pattern size, a w / photoresist mask is used, which is suitable for laser direct writing systems or electron beam lithography. Because of its function, the photoresist mask is then used to pattern the functional layer under the photoresist mask. This type of functional layer, which has been applied to a substrate in a preliminary process step, may be doped. Or it is a doped polycrystalline silicon layer, a silicon dioxide layer, a metal layer, and other functional layers that may be needed. During the worming operation, for example, by plasma etching in a suitable atmosphere, however, the lack of sufficient selectivity means that it is not possible to avoid corrosion of the etching mask. If a metal finish is applied, for example, a etched layer or a copper etched layer ', during the etching operation, it must also be confirmed that the passivated structure has been sufficiently passivated. By-products, especially carbon compounds, are formed during the etching operation, allowing passivation of the sidewalls in the etched metal structure. this
200402804 五、發明說明（2) 鈍化係以將光阻當作一個碳源為基礎並且經由在蝕刻氣 體大氣中的添加劑，例如氮、三氟曱烧、曱烧。 為了保護已經被蝕刻的鋁結構，以避免在蝕刻操作期 間經由蝕刻媒介而產生所不希望另外的腐蝕，其會更進 一步延伸深入至該金屬層，因而需要純化。 因為關於金屬蝕刻操作的低選擇性，必須被完全穿透 蝕刻的金屬層之最大高度，大大地被該光阻遮罩所限 制。 如上所述，在蝕刻操作期間，此光阻遮罩也會被蝕刻 而消失或者是被腐钱，因此，該金屬钱刻的深度主要是 由光阻遮罩的厚度來決定。而該光阻遮罩的厚度會受其 他的因素所限制，例如微影的製程範圍（p r 〇 c e s s w i ndow )與穩定度。 此等的問題導致硬式遮罩的發展與實際的利用，以用 來定義在鋁蝕刻之實例中的結構。目前所使用的此種型 式的硬式遮罩是由，例如，氧化矽、鎢、氮化鈦或者是 此等材料的組合物所構成。 一方面，硬式遮罩具有頗高於標準光阻遮罩的選擇 性，結果是在金屬層中產生比光阻遮罩較深的蝕刻溝 槽，其係依據另外的蝕刻參數。另一方面，所需要的側 壁鈍化可因光阻遮罩而更順利的達成，因為其在蝕刻操 作期間提供需要的碳。其亦已發現富含碳的步驟，例 如，由鈍化作用所引起.，對於不足的密度而言是特別有 利的。200402804 V. Description of the invention (2) Passivation is based on the use of photoresist as a carbon source and via additives in the atmosphere of the etching gas, such as nitrogen, trifluorine sintering, sintering. In order to protect the aluminum structure that has been etched from unwanted undesired additional corrosion via the etching medium during the etching operation, it will extend further into the metal layer and thus require purification. Because of the low selectivity with regard to metal etching operations, the maximum height of the etched metal layer that must be completely penetrated is greatly limited by the photoresist mask. As described above, during the etching operation, the photoresist mask is also etched and disappears or is corrupted. Therefore, the depth of the metal money is mainly determined by the thickness of the photoresist mask. The thickness of the photoresist mask may be limited by other factors, such as the lithographic process range (p r oc e s s w indow) and stability. These problems have led to the development and practical use of hard masks to define structures in the example of aluminum etching. This type of hard mask currently used is composed of, for example, silicon oxide, tungsten, titanium nitride, or a combination of these materials. On the one hand, hard masks have a higher selectivity than standard photoresist masks, and as a result, etched trenches deeper in the metal layer than photoresist masks are created, based on additional etching parameters. On the other hand, the required side wall passivation can be achieved more smoothly due to the photoresist mask because it provides the required carbon during the etching operation. It has also been found that carbon-rich steps, e.g. caused by passivation, are particularly advantageous for insufficient density.
第8頁 200402804 五、發明說明（3) 該硬式遮罩特有 的碳，此已經成為 因素，因為已產生 刻實例中側壁鈍化 烧，或者是至少在 制。 的不利條件為不能 與濺鍍的鋁層有關 相當大的腐蝕損害 所需的碳不能由氣 其所能達成的限度 k供側壁純化所需 方面的非常關鍵的 。同樣地，在鋁蝕 體所提供，例如曱 内仍有技術上的限 在美國第5，9 8 1，3 9 8號專利中，已揭露一種方法用以蝕 刻一結構，其中，首先藉由一光阻與已知的光微影製程 而ΐ生一硬式遮罩，並且此硬式遮罩然後被用來圖樣一 覆盍層（毯覆式目標層，blanket target layer〇。 為了使钱刻操作能夠利用含氯電漿而得以完成，該硬式 遮罩係由選自旋塗式玻璃材料（矽酸鹽類，31)丨11-〇11-g 1 a s s )與非晶形碳材料得一群組材料所組成。此硬式遮 罩層藉由一化學氣相沉積（C V D )、物理氣相沉積（p v D )或 者是可供選擇的高密度電漿化學氣相沉積（HDp_CVD， high-density plasma chemical vapor deposition)5 而被沉積在將被圖案化的層上，其可為一金屬層，然 後’在其上沉積一光阻層。另外，一種抗反射膜 (antireflection coating，ARC)層或者是一種緩衝層將 被安排在金屬層與硬式遮罩層之間，該Arc層可以為一種 二氧化石夕介電層。 接著利用其中一種已知光微影製程來圖案化一光阻以 形成一個第一遮罩，然後，該硬式遮罩可藉由一含氟的 第一電漿被圖案化，因此形成一第二蝕刻遮罩。然後利 200402804 五、發明說明（4) 用具有關於硬式遮罩的高選擇性的含氯電漿，進行隨後 的金屬層圖案化，以至於連相對較厚的金屬層（目標層） 可利用較為複雜的製程而被蝕刻。然而，此種方法的一 個缺點為必須利用不同的參數來完成複數個蝕刻步驟。 含有非晶形碳且藉由高密度電漿化學氣相沉積（HDP-CVD) 已經被沉積的該硬式遮罩層，同時也做為一碳源並利用 一含氧的蝕刻電漿。Page 8 200402804 V. Description of the invention (3) The carbon specific to the hard mask has become a factor, because the passivation of the sidewall in the engraved example has been generated, or at least in process. The disadvantage is that the considerable corrosion damage that cannot be associated with the sputtered aluminum layer can not be achieved by gas and the limits that it can achieve are very critical for the side wall purification. Similarly, in the aluminum etched body, for example, there is still a technical limitation in U.S. Patent No. 5,898,938, and a method has been disclosed for etching a structure. A photoresist and a known photolithography process create a hard mask, and this hard mask is then used to pattern a blanket layer (blanket target layer). In order to make money carving operations It can be completed by using a chlorine-containing plasma. The hard mask is a group selected from spin-on glass materials (silicates, 31), 11-〇11-g 1 ass) and amorphous carbon materials. Composed of materials. The hard mask layer is formed by a chemical vapor deposition (CVD), a physical vapor deposition (pv D), or an optional high-density plasma chemical vapor deposition (HDp_CVD) 5 It is deposited on the layer to be patterned, which may be a metal layer, and then a photoresist layer is deposited thereon. In addition, an antireflection coating (ARC) layer or a buffer layer will be arranged between the metal layer and the hard mask layer, and the Arc layer may be a dioxide dioxide dielectric layer. Then, one of the known photolithography processes is used to pattern a photoresist to form a first mask. Then, the hard mask can be patterned by a first plasma containing fluorine, thus forming a second mask. Etching mask. Then, 200402804 V. Description of the invention (4) Use a highly selective chlorine-containing plasma with a hard mask to perform subsequent metal layer patterning, so that even a relatively thick metal layer (target layer) can be used. Etched complex processes. However, a disadvantage of this method is that multiple etching steps must be performed using different parameters. The hard mask layer, which contains amorphous carbon and has been deposited by high-density plasma chemical vapor deposition (HDP-CVD), also serves as a carbon source and uses an oxygen-containing etching plasma.
本案是基於提供一個簡化的金屬圖案方法之目的，特 別是含鋁金屬層的圖案化，其被蝕刻的金屬結構係具有 充足的鈍化，以在蝕刻製程期間藉由簡單的方法而受到 保護。 本案所依據之目的已在前言中所描述的方法形式之實 例中達成，首先以碳層形式的一種硬式層被沉積在已經 被沉積且將被圖案化的金屬層上，然後沉積一光阻在該 硬式層上，而在該光阻層圖案化之後，藉由剝除 (stripping)而使碳層被圖案化以形成一碳遮罩，可定義 結構的碳遮罩然後被用來進行金屬蝕刻並同時進行側壁 的鈍化，接著該遮罩被剝除。This case is based on the purpose of providing a simplified metal patterning method, especially the patterning of an aluminum-containing metal layer. The etched metal structure has sufficient passivation to be protected by a simple method during the etching process. The purpose on which this case is based has been achieved in an example of the method form described in the preface. First, a hard layer in the form of a carbon layer is deposited on a metal layer that has been deposited and will be patterned. On the hard layer, after the photoresist layer is patterned, the carbon layer is patterned by stripping to form a carbon mask. The carbon mask with a definable structure is then used for metal etching. At the same time, the passivation of the side wall is performed, and then the mask is stripped.
在形成碳層上，純碳是較佳的選擇，雖然碳氫化石夕 (SiCH)或是碳氧化矽（Si 0C)也被使用，其尚可使用碳氫 化矽（SiCH)。 一 w/頂蓋層可同時被沉積在該碳層與光阻之間。 本案特別的優點是在硬式遮罩上，根據本案，其達成 許多功能，因為，首先是將被钱刻的結構被定義，且在In forming a carbon layer, pure carbon is a better choice, although silicon hydride (SiCH) or silicon oxycarbide (Si 0C) is also used, it is also possible to use silicon hydrocarbon (SiCH). A w / cap layer can be deposited simultaneously between the carbon layer and the photoresist. The particular advantage of this case is that on the hard mask, according to this case, it achieves many functions, because, first of all, the structure to be carved by money is defined, and
第10頁 200402804 五、發明說明（5) 同時提供一豐富的碳源以進行蝕刻的金屬結構的側壁鈍 化。與在其他方面已習慣使用的硬式遮罩比較之下，藉 由側壁鈍化，例如氧化矽（Si 0)、氮氧化矽（Si 0N)等，可 達到適合的保護，因而可避免已知鋁腐蝕的問題。 再者，因為在其他方面額外需要的蝕刻停止層，例如 一介電ARC層，假使該硬式遮罩係由碳氫化矽所構成時， 由於此層足以抵抗氧氣，其可以被省掉。由此事實，金 屬圖案亦可被大大的簡化。 本案將由以下示範性實施例來做較詳細之說明，其 中： 第一圖係為概略地描繪出將被圖案在一矽基質1上的一 個層結構。一銅銘金屬層2，藉由一習用的C V D步驟，已 被沉積在該石夕基質上。此金屬層2包含一鈦的薄層堆疊 (5 0 n m左右）、厚度大約為1 0 0 0 n m左右的一銅铭層，其 係在氮化鈦薄層（4 0 n m左右）之上。或是，該金屬層2也 可以包含由一非常薄（1 0 n m左右）的鈦層所組成的一個堆 疊、一個較厚（ 4 0 0 nm左右）的銅鋁層、另外一個非常薄 (5 ήπιέ右）的鈦層以及一氮化鈦層（40 n m左右）。 ! 在金屬層2上有一碳層3，厚度在20 0至500 nm左右，接 著依序為一 w/頂蓋層4 (氧氮化石夕），然後是一光阻5。 該w /頂蓋層4係在微影期間係被用來做為一停止層。 第二圖係顯示在第一圖中所示層結構在光阻4已被光微 影地圖案化之後，例如藉由D U V、i - Π n e等。然後，w / 頂蓋層4與在其下的碳層3可在原處被蝕刻，換言之，是Page 10 200402804 V. Description of the invention (5) At the same time, a rich carbon source is provided to blunt the sidewalls of the metal structure for etching. Compared with hard masks that have been used in other aspects, suitable protection can be achieved by side wall passivation, such as silicon oxide (Si 0), silicon oxynitride (Si 0N), etc., thus avoiding known aluminum corrosion The problem. Furthermore, because an additional etch stop layer is needed in other aspects, such as a dielectric ARC layer, if the hard mask is made of silicon hydride, this layer can be omitted because it is sufficiently resistant to oxygen. From this fact, the metal pattern can also be greatly simplified. This case will be described in more detail by the following exemplary embodiments, in which: The first figure is a rough outline of a layer structure to be patterned on a silicon substrate 1. A copper metal layer 2 has been deposited on the stone matrix through a conventional CVD step. The metal layer 2 includes a thin layer stack of titanium (about 50 nm) and a copper layer having a thickness of about 100 nm, which is over a thin layer of titanium nitride (about 40 nm). Alternatively, the metal layer 2 may also include a stack consisting of a very thin (about 100 nm) titanium layer, a thicker (about 400 nm) copper-aluminum layer, and another very thin (5 price (right) and a titanium nitride layer (about 40 nm). There is a carbon layer 3 on the metal layer 2 with a thickness of about 200 to 500 nm, followed by a w / cap layer 4 (oxynitride), followed by a photoresist 5. The w / cap layer 4 is used as a stop layer during lithography. The second diagram shows the layer structure shown in the first diagram after the photoresist 4 has been patterned by photolithography, such as by D U V, i-Π n e, and so on. The w / cap layer 4 and the carbon layer 3 underneath can then be etched in place, in other words, is
第11頁 200402804 五、發明說明（6) - 同時地。其結果是第三圖中所示之硬式遮罩，其可藉由 ， 金屬蝕刻而被直接用來圖案該金屬層2。 < 第四圖係顯示在金屬I虫刻後的層結構，該金屬層2已被 ' 完全地蝕刻穿透。蝕刻溝槽6延伸進入基質1中，而金屬 層2的側壁則被鈍化。 接著，該碳層3的剩餘部分在原處被剝除，在蝕刻溝槽 中存在的任何#刻殘餘可藉由，例如濕化學（w e ίο h e m i c a 1 )處 理方法 ，而被 移除。 最後，第六圖係顯示根據本案的方法所完成的金屬結 構。Page 11 200402804 V. Description of Invention (6)-Simultaneously. The result is a hard mask shown in the third figure, which can be directly used to pattern the metal layer 2 by metal etching. < The fourth figure shows the layer structure after the metal I was etched, and the metal layer 2 has been completely etched through. The etched trench 6 extends into the substrate 1, and the sidewalls of the metal layer 2 are passivated. Then, the remaining portion of the carbon layer 3 is stripped in place, and any #etched residues existing in the etched trench can be removed by, for example, a wet chemical (we e ο h e m i c a 1) treatment method. Finally, the sixth figure shows the metal structure completed according to the method of the present case.
第12頁 200402804 圖式簡單說明 第1圖顯示已被建構在一矽基質上的一個堆疊係包含一碳 硬式遮罩與在其上的一 w/頂蓋層以及位於後者上的一光 阻。 第2圖顯示在利用有圖案的光阻的微影之後的堆疊。 第3圖顯示在形成該硬式遮罩與該w/頂蓋層的開口後之 堆疊。 第4圖顯示在金屬蝕刻後在蝕刻溝槽中硬式遮罩與一聚合 層的剩餘堆疊。 第5圖顯示硬式遮罩已被剝除後的堆疊。 第6圖顯示在移除聚合物後具有圖案的金屬層的堆疊。Page 12 200402804 Brief Description of Drawings Figure 1 shows that a stack system that has been constructed on a silicon substrate includes a carbon hard mask with a w / cap layer on it and a photoresist on the latter. Figure 2 shows the stack after lithography using a patterned photoresist. Figure 3 shows the stacking after the hard mask and the opening of the w / cap layer are formed. Figure 4 shows the remaining stack of a hard mask and a polymeric layer in an etched trench after metal etching. Figure 5 shows the stack with the rigid masks removed. Figure 6 shows a stack of patterned metal layers after the polymer is removed.
元件符號說明： 1. 基質 2. 銘銅金屬層 3 ·碳 4 . w /頂蓋層 5. 光阻 6. 蝕刻溝槽 7 . #刻殘留物Description of component symbols: 1. Substrate 2. Copper metal layer 3 · Carbon 4. W / Top cap layer 5. Photoresist 6. Etching groove 7..
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