1236703 五、發明說明（1) 【發明所屬之技術領域】 本發明係關於一種形成接觸洞的方法，特別是關於一 種使用T型圖案來形成較小接觸洞的方法。 【先前技術】 當半導體的製程技術朝深次微米（deep submicron)前 進之趨勢下，現今的微影系統光學設計之解析度已達到系 統極限，因此目前普遍的趨勢皆趨向使用特別設計處理的 光罩如光學近接修正（optical proximity correction， 0PC)和相移光罩（phase shift mask ，PSM)來提升解析 度0 光學近接修正係因為於圖 長時’例如在微細的長方形圖 為光線的繞射，產生圓角現象 的技術如加入輔助圖案或改變 在光罩上部分區域加上一層相 layer)，雖然光學近接修正和 下的線路，但是其光罩的製作 度卻大幅度的增加製程上的成 鑒於上述問題，因此，本 來形成縮小線圖形的方法，其 新製程機台之前提下，來達到 洞尺寸，更大幅度的降低深次 巨額成本花費，而有效的提高 【發明内容】 案的限寬小於曝光光源的波 案中，圖案的四個角落將因 ，因而需使用光學近接修正 圖案線條。而相移式光罩是 移層（phase shi ft 相移光罩可以製作深次微米 和檢測，及線路設計的複雜 〇 發明提出一種使用τ型圖案 在無開發新的材料，無導入 深次微米尺寸下所需的接觸 微米製程上於光罩設計上的 產品的市場競爭力。1236703 V. Description of the invention (1) [Technical field to which the invention belongs] The present invention relates to a method for forming a contact hole, and more particularly to a method for forming a smaller contact hole using a T-shaped pattern. [Previous technology] As semiconductor process technology advances toward deep submicron, the resolution of the optical design of today's lithography systems has reached the system limit, so the current general trend is to use specially designed light Covers such as optical proximity correction (0PC) and phase shift mask (PSM) to improve the resolution. 0 Optical proximity correction is due to the length of the picture, such as the diffraction of light in a fine rectangular diagram. The technology that produces rounded corners, such as adding auxiliary patterns or changing a layer on the photomask, adds a layer of layer). Although the optical proximity correction and the lower circuit, the production of the photomask has greatly increased the manufacturing process. In view of the above problems, the original method of forming a reduced line pattern was previously proposed in the new process machine to achieve the hole size, which can greatly reduce the deep and huge cost and effectively improve the content of the invention. In wave cases where the width limit is smaller than the exposure light source, the four corners of the pattern will be affected by optical proximity correction. Case line. The phase shift mask is a layer shift (phase shi ft phase shift mask can make deep sub-micron and detection, and the complexity of the circuit design. Invented a new type of use of τ-type pattern without the development of new materials, no introduction of deep sub-micron The market competitiveness of the products required in the contact micron manufacturing process for the mask design required by the size.
第5頁 1236703 五、發明說明（2) 本發明之主要目的，在於提供一種使用T型圖案來形 成較小接觸洞的方法，其係能夠有效的降低在進入深次微 米製程下，形成一具有較小尺寸的接觸洞的成本。 本發明之另一目的，在於提供一種使用T型圖案來形 成較小接觸洞的方法，其無須使用高成本之相位移光罩即 可以形成相同適用於深次微米製程下的接觸窗尺寸。 本發明之再一目的，在於提供一種使用T型圖案來形 成較小接觸洞的方法，其無須研發新的材料，無須導入新 的複雜度高的製程機台，即可形成具有較小尺寸的接觸洞 〇 為達上述之目的，本發明提供一種使用T型圖案來形 成較小接觸洞的方法，其步驟有首先提供一半導體基底； 然後於半導體基底上依序形成一氧化層，一硬罩幕層以及 一化學增強型光組層；利用一光罩對化學增強型光阻層進 行曝光；接續通入一含氨的氣體，使氨離子捕捉化學增強 型光阻層頂端的氫離子，然後再對化學增強型光阻層進行 烘烤、顯影，以形成一 T型圖案化光阻層；最後，以T型圖 案化光阻層為罩幕對硬罩幕層進行蝕刻，然後移除T型圖 案化光阻層，再以硬罩幕層為罩幕，對氧化層進行蝕刻， 然後移除硬罩幕層，以獲得一具較小尺寸之接觸洞。 茲為使 貴審查委員對本發明之目的、技術内容、特 點及所達成之功效更有進一步之瞭解與認識，謹佐以較佳 之實施例圖及配合詳細之說明，說明如後： 【實施方式】Page 5 12367703 V. Description of the invention (2) The main purpose of the present invention is to provide a method for forming smaller contact holes using a T-shaped pattern, which can effectively reduce the formation of Cost of smaller contact holes. Another object of the present invention is to provide a method for forming a small contact hole by using a T-shaped pattern, which can form a contact window of the same size suitable for deep sub-micron processes without using a costly phase shift mask. Yet another object of the present invention is to provide a method for forming smaller contact holes using a T-shaped pattern, which does not require the development of new materials, and does not require the introduction of a new high-complexity process machine to form a small-sized contact hole. Contact hole 0 In order to achieve the above-mentioned object, the present invention provides a method for forming a smaller contact hole using a T-shaped pattern. The steps include firstly providing a semiconductor substrate; then sequentially forming an oxide layer on the semiconductor substrate and a hard mask. A curtain layer and a chemically-enhanced photoresist layer; a photomask is used to expose the chemically-enhanced photoresist layer; an ammonia-containing gas is continuously passed through so that ammonia ions capture hydrogen ions at the top of the chemically-enhanced photoresist layer, The chemically enhanced photoresist layer is then baked and developed to form a T-shaped patterned photoresist layer. Finally, the T-shaped patterned photoresist layer is used as a mask to etch the hard mask layer, and then the T is removed. Pattern the photoresist layer, and then use the hard mask layer as the mask to etch the oxide layer, and then remove the hard mask layer to obtain a contact hole with a smaller size. In order to make your review members better understand and understand the purpose, technical content, features and achieved effect of the present invention, I would like to refer to the preferred embodiment diagrams and detailed descriptions as follows: [Implementation Mode]
1236703 五、發明說明（3) 本發明係為一種使用T型圖案來形成較小接觸洞的方 法’請參閱第一圖至第六圖’係為本發明之一較佳實施例 之各步驟構造剖視圖。 首先請參閱第一圖’在一半導體基底10上依序形成一 氧化層1 2，一硬罩幕層1 4，以及一化學增強型光阻層 (chemical amplified resist’ CAR)16，其中硬罩幕層 14 的材質可以為氮氧化矽（S i ON)或氮化矽等其它材質，而以 低壓化學氣相沉積法沉積而得。然後，如第二圖所示，以 一具有較大接觸洞圖案的光罩1 8為罩幕，對化學增強型光 阻層1 6進行曝光，此時因為化學增強型光阻層丨6是將鹼性 可溶的聚羥苯乙烯（polyhydroxy styrene)上的氫氧基用 保護基（p r 〇 t e c t i ο n s i t e )遮蔽後，再配合光酸產生劑 (photo acid generator，PGA)，而成為鹼性顯像液不溶 的樹脂，所以對化學增強型光阻層i 6進行曝光步驟時，將 使化學增強型光阻層1 6上光酸產生劑將保護基分解（產生 分解反應的光阻層部分在第二圖中係以斜線表示），而暴 露出氫氧基（於圖中未示）。然後對半導體基底1〇表面通入 一含有氨的氣氛，使氨離子（NH 3)捕捉化學增強型光阻層 頂端的氫離子（H+)，如此將導致化學增強型光阻層16頂端 的氫離子呈現缺少的狀態，而導致無法參與顯影反應。接 續，以大約1 0 0°C對化學增強型光阻層1 6進行烘烤以催化 光阻的斷鍵，用以形成曝光時形成的潛在影像，最後再進 行顯影，以形成一如第三圖所示之T型圖案化光阻層2 0。 接著，以T型圖案化光阻層2 0為罩幕，以高密度電漿1236703 V. Description of the invention (3) The present invention is a method for forming a small contact hole using a T-shaped pattern. 'Please refer to the first to sixth figures' is a step structure of a preferred embodiment of the present invention Sectional view. First, please refer to the first figure, 'An oxide layer 12 is formed on a semiconductor substrate 10, a hard mask layer 14 is formed, and a chemically amplified resist' CAR 16 is formed. The material of the curtain layer 14 may be other materials such as silicon oxynitride (Si ON) or silicon nitride, and is deposited by a low pressure chemical vapor deposition method. Then, as shown in the second figure, the photo-enhanced photoresist layer 16 is exposed with a photomask 18 having a large contact hole pattern as a mask. At this time, the chemically-enhanced photoresist layer 6 is After shielding the hydroxyl group on the basic soluble polyhydroxy styrene with a protective group (pr tecti ο nsite), it is mixed with a photo acid generator (PGA) to become alkaline. The developer is insoluble in the developing solution, so when the chemically-enhanced photoresist layer i 6 is subjected to the exposure step, the photoacid generator on the chemically-enhanced photoresist layer 16 will decompose the protective group (the portion of the photoresist layer that generates decomposition reaction In the second figure, it is indicated by diagonal lines), and the hydroxyl group is exposed (not shown in the figure). Then, an atmosphere containing ammonia is passed through the surface of the semiconductor substrate 10, so that the ammonia ions (NH 3) capture hydrogen ions (H +) at the top of the chemically enhanced photoresist layer. This will cause hydrogen at the top of the chemically enhanced photoresist layer 16. The ions are in a state of lacking, which makes them unable to participate in the development reaction. Next, the chemically-enhanced photoresist layer 16 is baked at about 100 ° C to catalyze the breaking of the photoresist to form a potential image formed during exposure. Finally, it is developed to form a third image. The T-shaped patterned photoresist layer 20 shown in the figure. Next, a T-patterned photoresist layer 20 is used as a mask, and a high-density plasma is used.
第7頁 1236703 五、發明說明（4) 钱刻系統對硬罩幕層！ ▲ 阻層20為一具有較大了貝^ =餘刻，此時因為T型圖案化光 幕層U姓刻時’能夠穿積的Τ型形狀，將使得於硬罩 而轉移形成一較原本Ϊ 刻/ 22的電聚#刻束變小，因 之接觸窗24圖案於硬ϋ；8(參閱第二圖）上接觸窗尺寸小 |光阻層20,如第四圖戶U層14上，然後，移除T型圖案化 睛參閱第五圖，嚴彡么、 1 2進行蝕刻，然後如第^硬罩幕層1 4為罩幕，對氧化層 I成於氧化層12上形成—2二所不，移除硬罩幕層14，即形 更者，為避免於移上有 1 較Λ尺寸之接觸洞26。 硬罩幕層是否完全移除貪· /幕層At14時，因無法正確判斷 =層12造成損傷，因：可如度；钱刻’而對 層Η前’先於氧化層12上沉基_ 積硬罩幕 —底硬罩幕層28,其中底硬罩幕声 硬罩幕層快之 氮化…它材質，；以=質^為氮氧化 ς =而得。而本發明之製程在移除硬罩幕展予^相沉積法 2轉變於移除硬罩幕層14時同時移除底硬的步驟， p底硬罩幕層28受到蝕刻移除的速率快於^層28’但因 ，有效的保護氧化層1 2於習知硬罩幕層丨 幕層1 4，因 I化層12產生的損傷。 參曰14移除時可能對氧 本發明使用Τ型圖案來形成較小接觸洞 ^ ^形成具有較小尺寸的接觸窗，而可以適用法―，不但 、奩X大幅増加的深次微米製程，更能夠有；兀件的積 到形成具有較小尺寸所需花費的光罩 、降低習知為 大幅度的提 第8頁 1^1 1236703 五、發明說明（5) 高了產品的市場競爭力。 惟以上所述者，僅為本發明一較佳實施例而已，並非 用來限定本發明實施之範圍，故舉凡依本發明申請專利範 圍所述之形狀、構造、特徵及精神所為之均等變化與修飾 ，均應包括於本發明之申請專利範圍内。Page 7 1236703 V. Description of the invention (4) The money engraving system is on the hard cover curtain layer! ▲ The resist layer 20 has a larger size. At this time, because the T-shaped patterned light curtain layer U is engraved with a T-shape that can be engraved, it will be transferred to the hard cover to form a more original shape.刻 刻 / 22 的 电 聚 # The beam becomes smaller, so the contact window 24 is patterned on the hard ridge; 8 (see the second figure) The size of the contact window is small | Photoresistive layer 20, as shown in the fourth figure U layer 14 Then, remove the T-shaped patterning eye. Refer to the fifth figure, Yan Yan, 1 2 to etch, and then as the first hard mask layer 14 is a mask, the oxide layer I is formed on the oxide layer 12- 2 No, remove the hard cover curtain layer 14, that is, change the shape, in order to avoid having a contact hole 26 with a size larger than Λ. Whether the hard cover curtain layer has been completely removed. / When the curtain layer At14 cannot be correctly judged = the damage caused by layer 12 is due to: the degree of availability; Built-up hard cover—the hard-covered bottom layer 28, of which the hard-covered bottom cover is quickly nitrided ... it is made of materials; it is obtained by oxidizing nitrogen. In the process of the present invention, when the hard mask is removed, the phase deposition method 2 is changed to the step of removing the bottom hardness at the same time when the hard mask layer 14 is removed. The p bottom hard mask layer 28 is quickly removed by etching. Because of the 28 layer, the oxide layer 12 is effectively protected from the conventional hard cover curtain layer 丨 the curtain layer 14 and the damage caused by the I layer 12. When the reference 14 is removed, the T-type pattern may be used to form smaller contact holes in the present invention. ^ To form a contact window with a smaller size, the method can be applied. It can be more; the accumulation of the components to form a photomask with a smaller size, and the reduction of conventional knowledge is greatly improved. Page 8 1 ^ 1 1236703 V. Description of the invention (5) The market competitiveness of the product is higher . However, the above is only a preferred embodiment of the present invention, and is not intended to limit the scope of implementation of the present invention. Therefore, for example, changes in shape, structure, characteristics, and spirit in accordance with the scope of the patent application for the present invention are equivalent. Modifications should be included in the scope of patent application of the present invention.
1236703 圖式簡單說明 【圖示簡單說明】 第一圖至第六圖為本發明之各步驟構造剖視圖。 第七圖係為本發明於氧化層上加入一底硬罩幕層後之構造 剖視圖。 【圖號對照說明】 1 〇半導體基底 1 2氧化層 1 4硬罩幕層 1 6化學增強型光阻層 18光罩 2 0 T型圖案化光阻層 2 2触刻窗 2 4接觸窗 2 6接觸洞 2 8底硬罩幕層1236703 Brief description of the drawings [Simplified description of the drawings] The first to sixth drawings are cross-sectional views of the steps of the present invention. The seventh figure is a sectional view of the structure of the present invention after a hard cover curtain layer is added to the oxide layer. [Comparison of drawing number] 1 〇 Semiconductor substrate 1 2 Oxide layer 1 4 Hard cover curtain layer 1 6 Chemically enhanced photoresist layer 18 Photomask 2 0 T-patterned photoresist layer 2 2 Engraved window 2 4 Contact window 2 6 contact hole 2 8 bottom hard cover curtain layer
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