200925776 九、發明說明： 【發明所屬之技術領域】 本發明係關於一種形成遮罩圖案之方法，尤其是一種 可以透過根據化學增幅負光阻和化學增幅正光阻的組合之 曝光和顯影，減少圖案間距之形成遮罩圖案方法。 【先前技術】 隨著半導體產品小型化且高積體化，用以形成圖案之 圖案製作技術日益受到關注，以改善元件的新功能。現今 © 具有高積體度之圖案製作技術已發展成爲半導體製造的核 心技術，而且通常係使用微影製程。在微影製程中，塗佈 光阻（PR)(即，根據是否被光照射而反應之化學材料）而形成 光阻層。將光阻層曝光和顯影，因此形成遮罩圖案。使用 形成的遮罩圖案而將下層選擇性蝕刻和製作圖案。 一般而言，在製作圖案時所使用之光阻層曝光設備的 製程能力限制（解析度）係藉由半間距表示，其爲線圖案和 @ 間隔的總和所定義之圖案間距的一半。 根據半間距，到目前爲止所發展之曝光設備的解析度 爲45 nm »因此有必要減少圖案間距或半間距，以增加淨晶 粒數。 【發明內容】 本發明係針對形成具有圖案間距之遮罩圖案’其中透 過根據化學增幅負光阻和化學增幅正光阻的組合之曝光和 顯影，圖案間距爲曝光設備之解析度的一半。 根據本發明形成遮罩圖案之方法’負光阻層係形成在 200925776 基板上。負光阻層的一些區域被曝光。將曝光的負光阻層 顯影。在包含負型作用光阻層之基板上，形成正光阻層。 供烤基板，使氫氣擴散進入在負型作用光阻層邊界部分之 正光阻層。將被氫氣擴散進入之正光阻層顯影。 在負光阻層形成之前，可以另外形成底部抗反射塗層 (B ARC)。負光阻層和正光阻層的每一層都可以使用化學增 幅光阻而形成。 負型作用光阻層之間的間隔之總和可以具有間距，其 ❹ 爲曝光設備解析度的兩倍。考慮到氫氣透過烘烤而被擴散 進入負型作用光阻層側部的厚度，可將正光阻層形成爲使 在負型作用光阻層上面之厚度比氫氣將被擴散進入負型作 用光阻層側部之厚度薄。可將正光阻層形成爲使氫氣擴散 進入負型作用光阻層側面部之厚度比在負型作用光阻層上 面之厚度薄。 遮罩圖案可以具有圖案間距，其係藉由移除包含氫氣 〇 擴散進入負型作用光阻層側部之正光阻層而予以控制，以 具有目標距離。遮罩圖案可以包含負型作用光阻層和正型 作用光阻層，其中彼此相隔一個間隔且交替形成。 遮罩圖案被形成以使負型作用光阻層或正型作用光阻 層與間隔的總和具有與曝光設備之解析度相同的圖案間 距。 【實施方式】 現在，將參考附圖詳細說明根據本發明之特定實施例。 200925776 但是，本發明並不侷限於所揭露之實施例，而是可以 各種不同的方式實行。實施例被提供以完成本發明之揭 露，並且使本領域之具有普通技藝者瞭解本發明之範圍。 本發明係藉由申請專利範圍之範圍界定。 第1A圖到第1F圖爲說明根據本發明實施例形成遮罩 圖案之方法的剖視圖。 參考第1A圖，底部抗反射塗層（BARC)l 10形成在基板 100上。BARC層110具有控制曝光源之從基板100的表面 反射的反射光之功能。若適當，則可以不用形成BARC層 110° 負光阻層120形成在BARC層1 10上。負光阻層120 可以使用化學增幅光阻形成。 化學增幅光阻係指一種具有100%或更高的量子產生 率之阻劑。可以使用含有以樹脂及光酸產生劑（PAG)作爲構 成成分之反應抑制劑當作化學增幅光阻，以改善對比和控 制溶解度。化學增幅光阻可以採用基質樹脂，其中部份之 聚羥基苯乙烯（PHST)樹脂係由七-丁氧羰基（t-BOC)自由基 以適當的比例（n/m)所取代，以控制對於顯影劑的溶解度。 在此情形下，負光阻層1 20可以使用旋佈法形成。 參考第1B圖，負光阻層120的一些區域被曝光。可以 使用ArF或KrF當作曝光源。如上所述，藉由此曝光所形 成的酸會造成Ο-t-BOC狀態，其可以藉由將0-t-BOC分解 成0-H而溶解在鹼性溶液中。所得之當作副產品之氫（H + ) 200925776 氣被用以解除圍繞t-BOC的保護，並執行增幅作用。因此， 形成包含氫（H + )氣之經曝光的負光阻層120a。 尤其，根據本發明，圖案間距係藉由移除像氫（H + )氣 一樣厚之厚度而予以控制，該氫（H + )氣係透過後續的烘烤 製程而被擴散進入經曝光的負光阻層120a之側壁的正光阻 層（未圖示）。藉由透過曝光量的控制而控制氫（H + )氣被擴散 進入正光阻層的厚度來控制圖案間距。 參考第1C圖，將經曝光的負光阻層120a顯影。藉由 曝光所形成的氫（H + )氣開始與光阻產生交聯反應，因此經 曝光的負光阻層120a會殘留而不會被溶解在顯影劑中。因 此，形成負型作用光阻層120b (即，在曝光之後，曝光部分 會殘留而作爲圖案之光阻）。 在負型作用光阻層120b之間第一間隔120C的總和係 藉由圖案間距P1界定，而且係曝光設備解析度的兩倍。 參考第1D圖，正光阻層130形成在包含負型作用光阻 層120b之基板100上。正光阻層130可以由使用旋佈法之 化學增幅光阻形成。 形成在負型作用光阻層120b上之正光阻層130的厚 度，比由於透過後續烘烤製程而使氫（H + )氣擴散進入負型 作用光阻層1 20b的橫側所移除之厚度薄，所以顯影劑可以 滲透進入位在正光阻層（未圖示）下方之已擴散的氫（H + )氣。 參考第1E圖，烘烤有正光阻層130形成在其上之基板 1〇〇。因此，氫（H + )氣會擴散到負型作用光阻層120b之整 200925776 個表面上特定的厚度，於是形成已將氫（H + )氣擴散進入之 正光阻層130a。此時，已將氫（H + )氣擴散進入之正光阻層 13 0a被形成，使得負型作用光阻層120b的橫側之厚度比負 型作用光阻層120b上面的厚度厚。 參考第1F圖，只有將氫（H + )氣擴散進入之正光阻層 1 30被選擇性顯影。在此情形下，將氫（H + )氣擴散進入之正 光阻層130會被溶解在顯影劑之中，因此可以透過氫（H + ) 氣和光阻的分解反應而予以移除。結果，形成正型作用光 阻層1 3 0 b。 因此，負型作用光阻層120b和比負型作用光阻層120b 厚之正型作用光阻層130b係以第二間隔130c彼此分隔而 交替性重複之遮罩圖案140被完成。此時，正型作用光阻 層130b係形成在負型作用光阻層12〇b之間。因此，第二 間隔130c的距離比第ic圖的第一間隔120c窄，該第一間 隔120C係如將正型作用光阻層130b和第二間隔130c相加 的距離一樣多。 如上所述，遮罩圖案14〇具有圖案間距P2，其定義爲 負型作用光阻層120b或正型作用光阻層130b，和負型作用 光阻層1 2 0 b與正型作用光阻層13〇15之間的第二間隔13(^ 之總和。圖案間距P2變成目標距離。因此，根據本發明之 遮罩圖案140的圖案間距P2，比只採用負光阻層12〇的曝 光和顯影所形成之圖案間距p 1小1/2。換言之，根據本發 明之遮罩圖案140可以執行具有和曝光設備解析度相同距 200925776 離之圖案間距。 上述所形成的遮罩圖案1 40被用以當作用以形成實際 圖案之硬遮罩，如半導體元件製程之閘極或位元線。因此， 可以減少圖案間距，於是可以增加淨晶粒數。 根據本發明，具有比習知技術中只使用一種光阻層而 形成的圖案間距小1 /2之圖案間距之遮罩圖案，可以透過 根據化學增幅負光阻和化學增幅正光阻的組合之曝光和顯 影而形成。 再者，根據本發明，可以藉由應用具有減少圖案間距 之遮罩圖案到半導體元件的製程以增加淨晶粒數。 本發明並不侷限於所揭露之實施例，而是可以各種不 同的方式實行。實施例被提供以完成本發明之揭露，並且 使具有本領域之普通技藝者瞭解本發明之範圍。本發明係 藉由申請專利範圍之範圍界定。 【圖式簡單說明】 第1A圖到第1F圖爲說明根據本發明實施例形成遮罩 圖案之方法的剖視圖。 【主要元件符號說明】 100 基板 110 BARC 層 120 負光阻層 120a 經曝光的負光阻層 120b 負型作用光阻層 -10· 200925776 120c 第 -- 間 隔 130 正 光 阻 層 130a 已 被 氫 (H + )氣 擴散進入之正光阻層 130b 正 型 作 用光阻 層 130c 第 二 間 隔 140 遮 罩 圖 案200925776 IX. Description of the Invention: [Technical Field] The present invention relates to a method of forming a mask pattern, in particular, a pattern that can be reduced by exposure and development according to a combination of chemically amplified negative photoresist and chemically amplified positive photoresist The method of forming a mask pattern by the pitch. [Prior Art] As semiconductor products are miniaturized and highly integrated, patterning techniques for forming patterns are attracting attention to improve new functions of components. Nowadays, patterning technology with high integration has developed into a core technology for semiconductor manufacturing, and it is usually a lithography process. In the lithography process, a photoresist (PR) is applied (i.e., a chemical material that reacts depending on whether it is irradiated with light) to form a photoresist layer. The photoresist layer is exposed and developed, thus forming a mask pattern. The underlying layer is selectively etched and patterned using the formed mask pattern. In general, the process capability limit (resolution) of the photoresist layer exposure apparatus used in patterning is represented by a half pitch which is half the pattern pitch defined by the sum of the line pattern and the @ spacing. Based on the half pitch, the resolution of the exposure equipment developed so far is 45 nm » so it is necessary to reduce the pattern pitch or half pitch to increase the net crystal grain number. SUMMARY OF THE INVENTION The present invention is directed to forming a mask pattern having a pattern pitch by exposure and development according to a combination of a chemically amplified negative photoresist and a chemically amplified positive photoresist, the pattern pitch being half of the resolution of the exposure apparatus. A method of forming a mask pattern according to the present invention 'negative photoresist layer is formed on a 200925776 substrate. Some areas of the negative photoresist layer are exposed. The exposed negative photoresist layer is developed. A positive photoresist layer is formed on the substrate including the negative-working photoresist layer. The substrate is baked to diffuse hydrogen into the positive photoresist layer at the boundary portion of the negative-working photoresist layer. It is developed by a positive photoresist layer that is diffused into the hydrogen gas. A bottom anti-reflective coating (B ARC) may be additionally formed before the formation of the negative photoresist layer. Each of the negative photoresist layer and the positive photoresist layer can be formed using a chemically amplified photoresist. The sum of the spaces between the negative-working photoresist layers may have a pitch which is twice the resolution of the exposure device. Considering the thickness of hydrogen gas diffused into the side of the negative-working photoresist layer by baking, the positive photoresist layer can be formed such that the thickness above the negative-working photoresist layer is diffused into the negative-type photoresist The thickness of the side of the layer is thin. The positive photoresist layer may be formed such that the diffusion of hydrogen gas into the side portion of the negative-working photoresist layer is thinner than the thickness of the negative-working photoresist layer. The mask pattern may have a pattern pitch that is controlled to have a target distance by removing a positive photoresist layer that diffuses hydrogen gas into the side of the negative-working photoresist layer. The mask pattern may include a negative-working photoresist layer and a positive-working photoresist layer, which are alternately formed at intervals and spaced apart from each other. The mask pattern is formed such that the sum of the negative-working photoresist layer or the positive-working photoresist layer and the spacer has the same pattern pitch as that of the exposure apparatus. [Embodiment] Now, a specific embodiment according to the present invention will be described in detail with reference to the accompanying drawings. 200925776 However, the invention is not limited to the disclosed embodiments, but can be implemented in a variety of different ways. The examples are provided to complete the disclosure of the invention, and the scope of the invention is to be understood by those of ordinary skill in the art. The invention is defined by the scope of the claims. 1A to 1F are cross-sectional views illustrating a method of forming a mask pattern according to an embodiment of the present invention. Referring to Fig. 1A, a bottom anti-reflective coating (BARC) 10 is formed on the substrate 100. The BARC layer 110 has a function of controlling the reflected light of the exposure source reflected from the surface of the substrate 100. If appropriate, the BARC layer 110° negative photoresist layer 120 may be formed on the BARC layer 110. The negative photoresist layer 120 can be formed using a chemically amplified photoresist. The chemically amplified photoresist refers to a resist having a quantum yield of 100% or more. A reaction inhibitor containing a resin and a photoacid generator (PAG) as a constituent component can be used as a chemically amplified photoresist to improve contrast and control solubility. The chemically amplified photoresist may be a matrix resin in which a part of the polyhydroxystyrene (PHST) resin is replaced by a hepta-butoxycarbonyl (t-BOC) radical in an appropriate ratio (n/m) to control The solubility of the developer. In this case, the negative photoresist layer 120 can be formed using a spin-drying method. Referring to FIG. 1B, some areas of the negative photoresist layer 120 are exposed. ArF or KrF can be used as the exposure source. As described above, the acid formed by this exposure causes a Ο-t-BOC state which can be dissolved in the alkaline solution by decomposing 0-t-BOC into 0-H. The resulting hydrogen (H + ) as a by-product is used to relieve the protection of the t-BOC and perform an amplification effect. Thus, an exposed negative photoresist layer 120a containing hydrogen (H + ) gas is formed. In particular, according to the present invention, the pattern pitch is controlled by removing a thickness as thick as hydrogen (H + ) gas which is diffused into the exposed negative through a subsequent baking process. A positive photoresist layer (not shown) on the sidewall of the photoresist layer 120a. The pattern pitch is controlled by controlling the thickness of the positive photoresist layer by controlling the diffusion of the amount of exposure of the hydrogen (H + ) gas into the positive photoresist layer. The exposed negative photoresist layer 120a is developed with reference to FIG. 1C. The hydrogen (H + ) gas formed by the exposure starts to undergo a crosslinking reaction with the photoresist, so that the exposed negative photoresist layer 120a remains without being dissolved in the developer. Therefore, the negative-working photoresist layer 120b is formed (i.e., after exposure, the exposed portion remains as a photoresist of the pattern). The sum of the first spaces 120C between the negative-working photoresist layers 120b is defined by the pattern pitch P1 and is twice the resolution of the exposure apparatus. Referring to Fig. 1D, a positive photoresist layer 130 is formed on a substrate 100 including a negative-working photoresist layer 120b. The positive photoresist layer 130 can be formed by a chemically amplified photoresist using a spin coating method. The thickness of the positive photoresist layer 130 formed on the negative-working photoresist layer 120b is removed by diffusing hydrogen (H + ) gas into the lateral side of the negative-working photoresist layer 120b due to the subsequent baking process. The thickness is so thin that the developer can penetrate into the diffused hydrogen (H + ) gas located below the positive photoresist layer (not shown). Referring to Fig. 1E, the substrate 1 on which the positive photoresist layer 130 is formed is baked. Therefore, hydrogen (H + ) gas diffuses to a specific thickness on the surface of the negative-working photoresist layer 120b on 200925776, thus forming a positive photoresist layer 130a into which hydrogen (H + ) gas has diffused. At this time, the positive photoresist layer 110a which has diffused hydrogen (H + ) gas into it is formed such that the thickness of the lateral side of the negative-working photoresist layer 120b is thicker than the thickness of the negative-working photoresist layer 120b. Referring to Fig. 1F, only the positive photoresist layer 1 30 which diffuses hydrogen (H + ) gas into it is selectively developed. In this case, the positive photoresist layer 130 which diffuses hydrogen (H + ) gas into the developer is dissolved in the developer, and thus can be removed by the decomposition reaction of hydrogen (H + ) gas and photoresist. As a result, a positive-working photoresist layer 1 3 0 b is formed. Therefore, the negative-working photoresist layer 120b and the positive-working photoresist layer 130b thicker than the negative-type photoresist layer 120b are separated from each other by the second interval 130c, and the mask pattern 140 which is alternately repeated is completed. At this time, the positive-working photoresist layer 130b is formed between the negative-working photoresist layers 12b. Therefore, the distance of the second interval 130c is narrower than the first interval 120c of the ic diagram, which is as much as the distance between the positive-working photoresist layer 130b and the second interval 130c. As described above, the mask pattern 14A has a pattern pitch P2 defined as a negative-type photoresist layer 120b or a positive-working photoresist layer 130b, and a negative-type photoresist layer 1 2 0 b and a positive-type photoresist The second interval 13 between the layers 13〇15 (the sum of the pattern pitches P2 becomes the target distance. Therefore, the pattern pitch P2 of the mask pattern 140 according to the present invention is smaller than that of the negative photoresist layer 12〇 only. The pattern pitch p 1 formed by development is smaller by 1/2. In other words, the mask pattern 140 according to the present invention can be performed with the pattern pitch of the same distance from the exposure device as 200925776. The mask pattern 144 formed above is used. To be used as a hard mask for forming an actual pattern, such as a gate or a bit line of a semiconductor device process. Therefore, the pattern pitch can be reduced, and thus the net number of crystal grains can be increased. According to the present invention, it has only A mask pattern having a pattern pitch of less than 1 / 2 formed by using a photoresist layer can be formed by exposure and development according to a combination of a chemically amplified negative photoresist and a chemically amplified positive photoresist. It is to be noted that the net crystal grain count can be increased by applying a mask pattern having a reduced pattern pitch to the semiconductor element. The present invention is not limited to the disclosed embodiment, but can be implemented in various different ways. The disclosure of the present invention is provided to enable those skilled in the art to understand the scope of the present invention. The present invention is defined by the scope of the claims. [FIG. 1A] FIG. 1A to FIG. A cross-sectional view of a method of forming a mask pattern according to an embodiment of the present invention. [Main element symbol description] 100 substrate 110 BARC layer 120 negative photoresist layer 120a exposed negative photoresist layer 120b negative-type photoresist layer-10 - 200925776 120c First - interval 130 positive photoresist layer 130a has been diffused into the positive photoresist layer 130b by hydrogen (H + ) gas. positive-working photoresist layer 130c second spacer 140 mask pattern
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