經濟部智慧財產局員工消f合作社印製 讀&7548 A7 5716twf.d〇c/008 β7 五、發明說明（/ ) 本發明是有關於一種半導體微影製程，且特別是有關於 一種縮小接觸窗開口尺寸的微影製程。 半導體的製程一般區分爲四個模組(module)，包括擴散 (diffusion)、蝕刻(etching)、薄膜(thin film)與黃光（photo)， 其中的黃光模組即是負責微影製程，主要的工作即是將光 罩(mask)上之圖案轉移至晶片上，以提供蝕刻模組良好的 蝕刻圖案’或是提供薄膜模組良好的摻雜(implant)圖案， 因此，微影製程的好與壞，直接控制著半導體製程的優與 劣。 在微影製程中，曝光機所提供的解析度與光源波長λ之 間的關係可以用下列關係式表示： R=K, λ / ΝΑ 其中，h是與光阻材料及製程條件相關的一個常數， 而NA則是曝光機鏡片系統的數値孔隙（numerical aperture ’ ΝΑ)的數値。由上述關係式可以得知，當曝光機 所使用的光源波長Λ越短，整個曝光機所提供的最低解析 能力就越小。而當曝光機鏡片系統的ΝΑ値越大，同樣的 整個曝光機所提供的最低解析能力就越小。爲了使光罩上 的圖案可以完全且精確的轉移至光阻層上，因此曝光機投 射至光阻層上的圖案，必須具備一定的聚焦深度（depth 〇f focus ’ DOF) ’已是整個光阻層，不論是在接近光阻層的 表面知或是接近晶片端，都能有相同的聚焦。一般而言， 以DOF來表示曝光機所提供的聚焦深度，其可以量化爲 下列關係式： 3 本μ紙張尺度適用中國國家標i (CNS)A4規格（21〇 X 297 — (請先閱讀背面之注意事項再填寫本頁) 訂* 457548 5716twf - doc/0〇8 五、發明說明（}) DOF= Κ2 λ / (ΝΑ)2 然而，爲了使曝光機的聚焦深度增加，光源的波長應該 越長越好，曝光機鏡片系統的ΝΑ値越小越好，而此結果 與解析度之要求相牴觸。 隨著積體電路的積集度越來越高，光罩圖案密度越來越 高，位元線、字元線甚至摻雜區以及電容器的線距寬(pitch) 越來越小，因此必須提高曝光機之解析度以轉移較精細之 圖案，然而，提高曝光機之解析度’就會損失聚焦深度。 反之’爲得到良好的圖案轉移效果，提高聚焦深度，則使 得解析度降低。 因此’當半導體進入深次微米（deep sub-micron)尺寸製 程時’爲兼顧聚焦深度與解析度’因而提高微影製程的困 難度，且降低了微影製程機台之使用壽命。又，習知爲解 決上述之困難’額外增加許多微影製程以及平坦化製程， 而造成製造成本提高的問題。 對於現今日新月異的半導體技術而百，提高積集度一直 是眾人追求的目標，所以如何開發線寬更低的製程技術， 已是諸多尖端技術人員目前努力的課題。在開發關鍵尺寸 (critical dimension，CD)更小，積集度（integration)更高的 製程技術中，微影製程(photolithography)是重要的關鍵步 驟之一。由於曝光光源的選擇，以及聚焦深度的限制，因 此微影之解析度(resolution)受到侷限。 然而，在微影製程中，曝光的解析度(resolution)及聚焦 深度(depth of focus，DOF)是微影品質的重要指標。由於半 4 本紙張尺度適用中國國家標準（CNS)A4規格（210 x 297公釐） (請先間讀背面之注意事項再填寫本頁) 訂---------線气 經濟部智慧財產局員工消費合作杜印製 經濟部智慧財產局員工消費合作社印製 457548 A7 5716twf.doc/008 B7 五、發明說明（A ) 導體積集度的增加需要更高的解析度，解決的方法之一就 是使用波長較短的光源，比如使用由KrF雷射所發出波長 爲2480A的深紫外線作爲曝光的光源。以KrF雷射所發出 波長爲2480A的深紫外光爲光源來說，雖然波長越短其解 析度會越佳，但聚焦深度會相對的變差，且製程預度 (process window)亦較窄。因此，近年來常利用相移式光罩 (phase shifting mask ; PSM)的微影技術來獲得較佳的解析 度。 相移式光罩(PSM)的基本原理是利用在傳統的光罩上， 增加一些相移層（shifter layer)，藉著相移層在曝光時所產 生的正反相干涉，使曝光機投射在晶片上的影像圖案有較 佳的解析度’其優點在於不需要使用新的光源，只要對光 罩進行修改就可以提昇原有曝光的解析能力。因此，爲了 改善傳統光罩的繞射現象，目前在晶圓的微影製程上，常 利用相移式光罩（PSM)提高微影製程中圖案轉移的解析 度。而一般常用的相移式光罩可分爲兩種，包括強相移式 光罩（strong PSM)與弱相移式光罩(weak PSM)兩種。 其中’在強相移式光罩的製作中，其爲了避免蝕刻所產 生的粒子掉落在開口暴露出的石英板上，使得暴露出的石 英板表面嚴重地凸出’而在光透過開口暴露出的石英板時 引起相缺陷(phase defect)的問題，因此在蝕刻石英板時需 經過多次的蝕刻步驟，故每次的蝕刻製程均會使存在於開 口上的粒子逐漸變小，故相缺陷可藉此獲得改進。然而， 在製作石英板的開口中卻增加了微影，曝光、顯影以及蝕 5 本紙張尺度適用中國國家標準（CNS)A4規格（210x 297公釐） (請先閱讀背面之注意事項再填寫本頁) 訂---------線{ 經濟部智慧財產局員工消費合作社印製 457548 A7 5716twf.doc/008 B7 五、發明說明（κ) 刻製程的次數，不僅增加製造成本，同時亦耗費了大量的 製作時間（cycle time)，極不符合經濟效益。 再者，開口在經蝕刻後，石英板暴露出的表面較不平整， 使得光在透過時，亦造成散射（scatter)的現象，導致光在 透過開口後的強度（intensity)不均。而當使用此強相移式 光罩在進行微影製程時，光罩透光強度的不均將使得光阻 的形狀不對稱，進而造成半導體元件尺寸上的誤差。除此 之外，使用強相移式光罩亦會有光罩在設計、製作與修補 上較爲困難等問題。 另外，使用弱相移式光罩所產生的問題在於當光罩所要 轉移至光阻的開口圖案十分靠近時，便經常會發生邊葉 效應（sidelobes effect)。 邊葉效應主要是由於光繞射之故，致使開口邊緣相對 應之光阻上所受之光強度相對較大，所以在開口周圍會 有一圈光阻也曝到光，此即爲邊葉效應。而邊葉效應將 致使相對應之光阻部分溶解，導致光阻厚度減少，造成 抵抗蝕刻的能力降低，進而致使後續製程會因此而發生 過度蝕刻、內連線導通不佳等問題。 此時若爲了減輕邊葉效應而減少曝光量，則可能會有 曝光不足之情況發生。故若要顧及曝光量，開口周圍又 會發生邊葉效應，造成製程上一個兩難的局面。 有鑑於此，本發明提出一種縮小接觸窗開口尺寸的微影 製程，其藉兩個不同的線/間距光罩(line/space mask)，將 長度與寬度爲彼此不同之線形圖樣影像相互交錯垂直所形 6 本紙張尺度適用中_囹家標準（CNS)A4規格（210 X 297公釐） (請先閱讀背面之注意事項再填寫本頁) ^---I I I I I « — — —— — 111 457548 A7 5716twf.doc/008 〇7 五、發明說明（ε) 成的接觸窗開口圖案經由曝光而移轉至一基材上。而在不 需使用複雜的光罩與特殊之曝光技術的情形下，可以達 到減小接觸窗開口之關鍵尺寸的目的。 由於在相同的K1値下，即相同的解析度下，利用習知 單一光罩製作接觸窗開口圖案的困難度遠高於線/間距光 罩，所以本發明提出一種接觸窗開口的微影製程，其包括 下列步驟：提供一塗佈有負光阻之晶片；經曝光後，將第 一線/間距光罩之第一圖案影像投影於負光阻上：之後， 再重複曝光，將第二線/間距光罩之第二圖案影像投影於 負光阻上，其中第一圖案影像與第二圖案影像相互交錯垂 直，以在負光阻上形成一接觸窗開口圖案；接著，晶片經 顯影後，在負光阻上形成接觸窗開口圖形。 本發明提出一種縮小接觸窗開口尺寸的微影製程，其中 長度與寬度爲彼此不同之線形圖樣影像相互交錯垂直所形 成的接觸窗開口圖案在使用一預定曝光源或一預定電價粒 子束下移轉至一預定基材上。此方法包括下列步驟：利用 一第一光罩產生一第一圖案，其中第一圖案爲彼此平行之 線形構形，及利用一第二光罩產生一第二圖案，其中第二 圖案爲彼此平行之線形構形；將第一圖案及第二圖案相互 交錯垂直之一影像重複曝光投影在一基材上以轉印此影像 至其上，其中基材爲一負光敏性材料塗覆；顯影基材，以在 負光敏性材料上形成所需之接觸窗開口圖形。 本發明係爲一種提供塗佈有負光阻之晶片，藉兩個不同 線/間距光罩之線形圖案相互交錯垂直形成一接觸窗開口圖 7 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公餐） (請先閱讀背面之注意事項再填寫本頁) 訂---------線(. 經濟部智慧財產局員工消費合作社印製 ^57548 A7 5716twf.doc/008 β7 五、發明說明（6) 案以製作接觸窗開口之微影製程，其可取代習知晶片上塗 佈正光阻，藉單一光罩製作接觸窗開口圖案之困難的微影 製程，而得以增加製程預度，及縮小接觸窗開口尺寸。 本發明係利用兩個不同線/間距光罩之線形圖案於重複 曝光後相互交錯垂直，獲得相互組合而成之接觸窗開口圖 案，而得以在負光阻層上形成所需之接觸窗開口圖形。由 於本方法可精確地控制線/間距光罩的線距寬，因而可降 低接觸窗開口的關鍵尺寸。所以，本發明之縮小接觸窗開 口尺寸的微影製程可以避免元件積集度增加，在製程上所 造成的困難度與限制。 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： 圖式之簡單說明： 第1圖爲接觸窗開口圖案； 第2A圖和第2B圖分別爲欲形成第1圖所示之接觸窗 開口圖案的第一線/間距光罩與第二線/間距光罩的示意 圖， 第3圖所繪示的是依照本發明一較佳實施例，一種縮小 接觸窗開口尺寸之微影製程的流程圖；以及 第4A圖至第4D圖所繪示的是依照本發明一較佳實施 例，一種縮小接觸窗開口尺寸之微影製程的製造流程剖面 不意圖。 其中，圖式之標記說明： 8 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） (請先閱讀背面之注意事項再填寫本頁) 訂---------線{ 經濟部智慧財產局員工消費合作杜印製 經濟部智慧財產局員工消費合作社印製 457548 A7 5716twf.doc/008 nj 五、發明說明（9) 100、400 :晶片 102 :接觸窗開口圖案 200 :透明底材 202 ' 204 ·_遮蔽層 203 :第一線/間距光罩 205 :第二線/間距光罩 402 :縱向曝光區域 404 :縱向光阻區域 406 :橫向曝光區域 408 :橫向光阻區域 410 :裸露區 412 :格狀光阻圖案 414 .接觸窗開口區域 實施例 本發明適用於對負光阻（negative resist)進行曝光所用 之光罩，所以負光阻在顯影之後，所留下的部分爲對應 至光罩上的透明區域。 第1圖爲接觸窗開口圖案，而第2A圖和第2B圖分別 爲欲形成第1圖所示之接觸窗開口圖案的第一線/間距光 罩與第二線/間距光罩示意圖。 光罩係微影製程中用以提供線路圖案轉移的主要工具， 故而其在積體電路的製程中扮演著極爲重要的角色。光罩 的主體係由平坦的透明底材所構成，而半導體元件各層的 圖案，則是在透明底材的表面上覆蓋一層遮蔽層以形成。 9 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） (請先閱讀背面之注意事項再填寫本頁) -^--OJf n 缝 經濟部智慧財產局員工消費合作社印製 457548 A7 _ 57l6twf.doc/008 R7 五、發明說明（8) 請同時參照第1圖、第2A圖與第2B圖，典型的光罩 係以玻璃或石英作爲透明底材200，而於底材200上形成 一層用以形成圖案的遮蔽層202。其中，遮蔽層202的材 質包括鉻，厚度約爲數百埃(A)左右，且石英板200上具 有鉻膜202覆蓋的部份爲光無法透過的部分。遮蔽層202(不 透光區）的形成方法係在透明底材200上覆蓋一層金屬層， 然後，再經由圖案的定義，以裸露出部份的透明底材200(透 光區），形成如第2A圖所示之第一線/間距光罩203。其中， 第一線/間距光罩的遮蔽層202(不透光區）與裸露出部份的 透明底材200(透光區）爲彼此平行之線形構形。 接著，再於另一以玻璃或石英爲材質之透明底材200上 形成一層用以形成圖案的遮蔽層204。其中，遮蔽層204 的材質包括鉻，厚度約爲數百埃（A)左右，且石英板200 上具有鉻膜2〇4覆蓋的部份爲光無法透過的部分。遮蔽層 2〇4(不透光區）的形成方法係在透明底材200上覆蓋一層金 屬層’然後，再經由圖案的定義’以裸露出部份的透明底 材2〇〇(透光區）’形成如第2B圖所示之第二線/間距光罩 205。其中’第二線/間距光罩的遮蔽層2〇4(不透光區）與裸 露出部份的透明底材200(透光區）爲彼此平行之線形構 形。 之後，曝光第一線/間距光罩，以將第一線/間距光罩之 第一圖案影像投影於晶片100之負光蛆上。接著，再重複 曝光第二線/間距光罩，以將第二線/間距光罩之第二圖案 影像投影於晶片100之負光阻上。其中，第一圖案影像與 本紙張尺度適用中國國家棵準（CNS)A4規格<2丨0 X 297公釐） (請先閱讀背面之注意事項再填寫本頁) 訂---------線一 45754 五 經濟部智慧財產局員工消費合作杜印製 A7 B7 、發明說明) 第〜圖案影像相互交錯垂直，以在晶片100之負光阻上形 成〜所需之接觸窗開口圖案102，如第1圖所示。 第3圖所繪75的TH依照本發明一較佳實施例，—種縮小 接觸窗開口尺寸之微影製程的流程圖。第4A圖至第4D 圖所繪示的是依照本發明一較佳實施例，一種縮小接觸窗 開口尺寸之微影製程的製造流程剖面示意圖。 請同時參照第3圖與第4A圖至第4D圖，首先提供一 塗佈有負光阻之晶片400(步驟300)。接著，利用如第2A 圖所不之第一線/間距光罩將第一影像（image)曝光投影於 塗佈有負光阻之晶片400上，以產生如第4B圖所示之由 縱向曝光區域402與光阻區域404相互交錯排列且相互平 行所形成的第一圖案（步驟302)。其中，曝光區域402相 對應於第2A圖所示之第一線/間距光罩之裸露出部份的透 明底材200(透光區），而光阻區域404相對應於第2A圖所 示之第一線/間距光罩之遮蔽層202(不透光區）。 之後，再利用如第2B圖所示之第二線/間距光罩將第二 影像重複曝光於先前已形成有第一圖案之晶片400的負光 阻上（如第4B圖），以產生如第4C圖所示之由橫向曝光區 域406與光阻區域408相互交錯排列且相互平行所形成的 第二圖案（步驟304)。其中，曝光區域406相對應於第2B 圖所示之第一線/間距光罩之裸露出部份的透明底材2〇〇(透 光區），而光阻區域408相對應於第2B圖所示之第一線/ 間距光罩之遮蔽層204(不透光區）。 而且，由於經重複曝光後的第一圖案與第二圖案相互交 本紙張尺度適用中國國家標準（CNS)A4規格（210^ 297公f ) (請先閱讀背面之注素孝項再填寫本頁) --------訂·-------- 457548 A7 57l6twf.doc/008 g7 五 '發明說明（〖C)) 錯垂直，使得第一圖案與第二圖案相互組合而成之接觸窗 開口圖案得以在負光阻上形成所需之接觸窗開口圖形。換 句話說，縱向光阻區域404與橫向光阻區域408交錯重疊 的部分即爲後續所欲形成接觸窗開口的裸露區410。其中， 第一線/間距光罩與第二線/間距光罩的線距寬(pitch)與尺 寸取決於所欲形成之接觸窗開口的長度（length)及寬度 (width)。 最後，將上述轉印有接觸窗開口圖案的負光阻經顯影之 後，形成如第4D圖所示之具有接觸窗開口圖形的格狀光 阻圖案412(步驟306)。而第4C圖所示之裸露區410的負 光阻將被去除，形成一接觸窗開口區域414。 本發明利用兩個不同線/間距光罩之線形圖案於重複曝 光後相互交錯垂直，獲得相互組合而成之接觸窗開口圖 案，而得以在負光阻層上形成所需之接觸窗開口圖形。且 由於第一線/間距光罩與第二線/間距光罩的線距寬與尺寸 取決於所欲形成之接觸窗開口的長度及寬度，而可任意的 調整，所以本方法不但可增加製程預度，且可藉精確地控Employees of the Intellectual Property Bureau of the Ministry of Economic Affairs, Cooperative Cooperative Printing & 7548 A7 5716twf.doc / 008 β7 V. Description of the Invention (/) The present invention relates to a semiconductor lithography process, and in particular to a method of reducing contact Photolithography process for window opening size. The semiconductor manufacturing process is generally divided into four modules, including diffusion, etching, thin film, and yellow light. The yellow light module is responsible for the lithography process. The main The job is to transfer the pattern on the mask to the wafer to provide a good etching pattern for the etching module 'or to provide a good implant pattern for the thin film module. Therefore, the lithography process is better Bad, directly controls the pros and cons of the semiconductor process. In the lithography process, the relationship between the resolution provided by the exposure machine and the wavelength λ of the light source can be expressed by the following relationship: R = K, λ / ΝΑ where h is a constant related to the photoresist material and process conditions And NA is the number of the numerical aperture (NAA) of the lens system of the exposure machine. From the above relationship, it can be known that the shorter the light source wavelength Λ used by the exposure machine, the smaller the minimum resolution provided by the entire exposure machine. As the NA of the exposure machine lens system is larger, the minimum resolution provided by the same exposure machine is smaller. In order for the pattern on the photomask to be completely and accurately transferred to the photoresist layer, the pattern projected on the photoresist layer by the exposure machine must have a certain depth of focus (depth 〇f focus 'DOF)' is the entire light The resist layer, whether it is known near the surface of the photoresist layer or near the wafer end, can have the same focus. In general, the DOF is used to represent the depth of focus provided by the exposure machine, which can be quantified as the following relationship: 3 This μ paper size is applicable to the Chinese National Standard i (CNS) A4 specification (21〇X 297 — (Please read the back first Please note this page and fill in this page) Order * 457548 5716twf-doc / 0〇8 5. Description of the invention (}) DOF = Κ2 λ / (ΝΑ) 2 However, in order to increase the depth of focus of the exposure machine, the wavelength of the light source should be increased. As long as possible, the smaller the NA of the exposure system lens system, the better, and this result conflicts with the requirements of resolution. As the integration of integrated circuits becomes higher and higher, the density of the mask pattern becomes higher and higher. The bit line, word line, and even the doped region and the pitch of the capacitor are getting smaller and smaller, so the resolution of the exposure machine must be increased to transfer finer patterns. However, the resolution of the exposure machine must be improved. The focus depth will be lost. Conversely, 'to obtain a good pattern transfer effect and increase the focus depth, the resolution will be reduced. Therefore, when the semiconductor enters the deep sub-micron size process, it is to focus on both focus depth and resolution. degree Therefore, the difficulty of the lithography process is increased, and the service life of the lithography process machine is reduced. Moreover, it is known that in order to solve the above-mentioned difficulties, many lithography processes and planarization processes are additionally added, which causes the problem of increasing manufacturing costs. For today's fast-changing semiconductor technology, improving accumulation has always been the goal pursued by everyone. Therefore, how to develop process technology with lower line width has been the subject of many cutting-edge technicians. In the development of critical dimensions, CD) is smaller and the integration is higher. Photolithography is one of the important key steps. Due to the choice of exposure light source and the limitation of focus depth, the resolution of lithography (resolution) is limited. However, in the lithography process, the resolution and depth of focus (DOF) of the exposure are important indicators of the quality of lithography. Because half of this paper ’s dimensions are in line with Chinese national standards ( CNS) A4 size (210 x 297 mm) (Please read the precautions on the back before filling this page) Order --------- line Printed by the Intellectual Property Bureau of the Ministry of Economic Affairs on the Consumer Cooperation Du printed by the Consumers Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs printed 457548 A7 5716twf.doc / 008 B7 V. Description of the Invention (A) The increase in the volume of the guided volume requires a higher resolution, One of the methods is to use a light source with a shorter wavelength, such as using deep ultraviolet light with a wavelength of 2480A emitted by a KrF laser as the light source for exposure. Taking deep ultraviolet light with a wavelength of 2480A emitted by a KrF laser as the light source, The shorter the wavelength, the better the resolution, but the focal depth will be relatively worse, and the process window will be narrower. Therefore, in recent years, a lithographic technique using a phase shifting mask (PSM) is often used to obtain better resolution. The basic principle of a phase shift mask (PSM) is to use a traditional mask to add some shifter layers. By the positive and negative interference generated by the phase shift layer during exposure, the exposure machine projects. The image pattern on the wafer has better resolution. 'The advantage is that it does not require the use of a new light source. As long as the mask is modified, the resolution of the original exposure can be improved. Therefore, in order to improve the diffraction phenomenon of the conventional photomask, currently, in the lithography process of the wafer, a phase shift photomask (PSM) is often used to improve the resolution of pattern transfer in the lithography process. There are two types of phase shift masks commonly used, including strong phase shift mask (strong PSM) and weak phase shift mask (weak PSM). Among them, in the production of a strong phase-shifting photomask, in order to prevent particles generated by etching from falling on the quartz plate exposed by the opening, so that the surface of the exposed quartz plate is seriously convex, the light is exposed through the opening. The resulting quartz plate causes a phase defect problem. Therefore, multiple etching steps are required when etching the quartz plate, so each etching process will gradually reduce the particles existing in the openings, so the phase Defects can be improved by this. However, lithography, exposure, development, and etching have been added to the openings of the quartz plate. This paper size applies the Chinese National Standard (CNS) A4 specification (210x 297 mm) (Please read the precautions on the back before filling in this Page) Order --------- line {Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 457548 A7 5716twf.doc / 008 B7 V. Description of the invention (κ) The number of engraving processes not only increases the manufacturing cost, but also It also consumes a lot of production time (cycle time), which is not very economical. Furthermore, after the opening is etched, the exposed surface of the quartz plate is relatively uneven, so that when light is transmitted, it also causes a phenomenon of scatter, resulting in uneven intensity of light after passing through the opening. When using this strong phase shift mask in the lithography process, the uneven light transmission intensity of the mask will cause the shape of the photoresist to be asymmetric, which will cause errors in the size of the semiconductor device. In addition, the use of strong phase-shifting reticle can also cause difficulties in designing, manufacturing, and repairing the reticle. In addition, the problem caused by the use of a weak phase shift mask is that when the opening pattern of the photomask to be transferred to the photoresist is very close, a sidelobes effect often occurs. The edge effect is mainly due to the diffraction of light, which causes the light intensity on the photoresist corresponding to the edge of the opening to be relatively large. Therefore, a circle of photoresist is also exposed to the light around the opening. This is the edge effect . The edge effect will cause the corresponding photoresist to partially dissolve, resulting in a reduction in the thickness of the photoresist and a reduction in the ability to resist etching, which in turn will cause problems such as excessive etching and poor interconnections in subsequent processes. In this case, if the exposure is reduced in order to reduce the edge effect, underexposure may occur. Therefore, if the exposure is to be taken into account, the edge effect will occur around the opening, which will cause a dilemma in the manufacturing process. In view of this, the present invention proposes a lithography process for reducing the opening size of a contact window, which uses two different line / space masks to intersect the line pattern images whose length and width are different from each other perpendicularly. Appearance 6 This paper size is applicable _Fujian Standard (CNS) A4 (210 X 297 mm) (Please read the precautions on the back before filling this page) ^ --- IIIII «— — — — — 111 457548 A7 5716twf.doc / 008 〇7 V. The description of the opening pattern of the contact window (ε) is transferred to a substrate through exposure. Without the need for complicated photomasks and special exposure technology, the key size of the contact window opening can be reduced. Under the same K1 値, that is, at the same resolution, it is much more difficult to make a contact window opening pattern using a conventional single mask than a line / space mask, so the present invention proposes a lithography process for contact window openings. It includes the following steps: providing a wafer coated with a negative photoresist; after exposure, projecting the first pattern image of the first line / space mask on the negative photoresist: after that, repeat the exposure and The second pattern image of the line / space mask is projected on the negative photoresist, wherein the first pattern image and the second pattern image are staggered and perpendicular to each other to form a contact window opening pattern on the negative photoresist. Then, after the wafer is developed, , Forming a contact window opening pattern on the negative photoresist. The present invention proposes a lithography process for reducing the size of a contact window opening. The contact window opening pattern formed by staggered and perpendicular line pattern images with mutually different lengths and widths is transferred using a predetermined exposure source or a predetermined electricity price particle beam. Onto a predetermined substrate. The method includes the following steps: generating a first pattern using a first mask, wherein the first pattern is a linear configuration parallel to each other, and generating a second pattern using a second mask, wherein the second pattern is parallel to each other A linear configuration; one image of the first pattern and the second pattern interlaced perpendicularly are repeatedly exposed and projected on a substrate to transfer the image onto the substrate, wherein the substrate is coated with a negative photosensitive material; a developing substrate Material to form the desired contact window opening pattern on the negative photosensitive material. The present invention is to provide a wafer coated with negative photoresist. A contact window opening is formed by staggering two linear patterns of two different line / space photomasks. Figure 7 This paper size is applicable to China National Standard (CNS) A4 specifications ( 210 X 297 Public Meal) (Please read the notes on the back before filling this page) Order --------- line (. Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs ^ 57548 A7 5716twf.doc / 008 β7 V. Invention Description (6) The lithography process for making contact window openings can replace the conventional lithography process of coating a positive photoresistor on a wafer, and the difficult lithography process of making a contact window opening pattern by a single photomask can be increased. The process is planned and the size of the opening of the contact window is reduced. The present invention uses two linear patterns with different line / spaced photomasks to stagger each other perpendicularly after repeated exposures to obtain contact window opening patterns that are combined with each other, and can be used in negative light. The required contact window opening pattern is formed on the resist layer. Since the method can accurately control the line width of the line / space photomask, the key size of the contact window opening can be reduced. Therefore, the contact window opening of the present invention is reduced. The lithography process with a mouth size can avoid the increase in the degree of component accumulation, and the difficulties and limitations caused by the process. In order to make the above-mentioned objects, features, and advantages of the present invention more obvious and understandable, a better implementation is given below. For example, and with the accompanying drawings, the detailed description is as follows: Brief description of the drawings: Figure 1 is the opening pattern of the contact window; Figures 2A and 2B are the opening pattern of the contact window shown in Figure 1 FIG. 3 is a schematic diagram of a first line / spaced photomask and a second line / spaced photomask. FIG. 3 is a flowchart of a lithography process for reducing the opening size of a contact window according to a preferred embodiment of the present invention; And FIGS. 4A to 4D show a cross-sectional view of the manufacturing process of a lithography process for reducing the opening size of a contact window according to a preferred embodiment of the present invention. Among them, the marks of the drawings explain: 8 sheets of paper Standards are applicable to China National Standard (CNS) A4 specifications (210 X 297 mm) (Please read the precautions on the back before filling this page) Order --------- Online {Economic Consumption of Employees of Intellectual Property Bureau, Ministry of Economic Affairs Du Printed Smart Money Printed by the Bureau ’s Consumer Cooperatives 457548 A7 5716twf.doc / 008 nj V. Description of the invention (9) 100, 400: Wafer 102: Contact window opening pattern 200: Transparent substrate 202 '204._Shielding layer 203: First line / Pitch mask 205: Second line / pitch mask 402: Vertical exposure area 404: Vertical photoresist area 406: Horizontal exposure area 408: Horizontal photoresist area 410: Bare area 412: Lattice photoresist pattern 414. Contact window opening Region Example The present invention is applicable to a photomask used for exposure of a negative resist, so after the negative photoresist is developed, the remaining portion corresponds to a transparent region on the photomask. Fig. 1 is a contact window opening pattern, and Figs. 2A and 2B are schematic diagrams of a first line / spaced mask and a second line / spaced mask to form the contact window opening pattern shown in Fig. 1, respectively. The photomask is the main tool used to provide circuit pattern transfer in the lithography process, so it plays an extremely important role in the fabrication of integrated circuits. The main system of the photomask is composed of a flat transparent substrate, and the pattern of each layer of the semiconductor element is formed by covering a surface of the transparent substrate with a shielding layer. 9 This paper size is in accordance with China National Standard (CNS) A4 (210 X 297 mm) (Please read the precautions on the back before filling this page)-^-OJf n Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Sewing Economy 457548 A7 _ 57l6twf.doc / 008 R7 V. Description of the invention (8) Please refer to Figure 1, Figure 2A, and Figure 2B at the same time. The typical photomask uses glass or quartz as the transparent substrate 200, and the substrate A masking layer 202 is formed on 200 to form a pattern. The material of the shielding layer 202 includes chromium and has a thickness of about several hundred angstroms (A). The portion of the quartz plate 200 covered with the chromium film 202 is a portion where light cannot pass. The masking layer 202 (opaque area) is formed by covering a transparent metal substrate 200 with a metal layer, and then defining the pattern to expose a part of the transparent substrate 200 (light-transmitting area), such as The first line / space mask 203 shown in FIG. 2A. Wherein, the shielding layer 202 (opaque area) of the first line / space mask and the transparent substrate 200 (transparent area) of the exposed portion have a linear configuration parallel to each other. Next, a masking layer 204 for forming a pattern is formed on another transparent substrate 200 made of glass or quartz. The material of the shielding layer 204 includes chromium and has a thickness of about several hundred angstroms (A). The portion of the quartz plate 200 covered by the chromium film 204 is a portion that cannot be transmitted by light. The method for forming the shielding layer 204 (opaque area) is to cover the transparent substrate 200 with a metal layer 'then, and then pass through the definition of the pattern' to expose a part of the transparent substrate 200 (transparent area). ) 'Forms a second line / space mask 205 as shown in FIG. 2B. Among them, the shielding layer 204 (opaque area) of the second line / space mask and the transparent substrate 200 (transparent area) of the exposed portion are in a linear configuration parallel to each other. After that, the first line / space mask is exposed to project the first pattern image of the first line / space mask onto the negative beam of the wafer 100. Then, the second line / space mask is repeatedly exposed to project the second pattern image of the second line / space mask onto the negative photoresist of the wafer 100. Among them, the first pattern image and this paper size are applicable to China National Standard (CNS) A4 specifications < 2 丨 0 X 297 mm) (Please read the precautions on the back before filling this page) Order ------ --- Line one 45754 Consumer cooperation of the Intellectual Property Bureau of the Ministry of Economic Affairs Du printed A7 B7, description of the invention) The ~ pattern image is staggered and perpendicular to each other to form the required contact window opening pattern on the negative photoresistor of the chip 100 102, as shown in Figure 1. The TH of 75 shown in FIG. 3 is a flowchart of a lithography process for reducing the size of a contact window opening according to a preferred embodiment of the present invention. 4A to 4D are schematic cross-sectional views illustrating a manufacturing process of a lithography process for reducing the opening size of a contact window according to a preferred embodiment of the present invention. Please refer to FIG. 3 and FIG. 4A to FIG. 4D at the same time. First, a wafer 400 coated with a negative photoresist is provided (step 300). Next, the first image is exposed and projected on the wafer 400 coated with a negative photoresist using a first line / space mask as shown in FIG. 2A to generate a longitudinal exposure as shown in FIG. 4B. The first pattern formed by the regions 402 and the photoresist regions 404 are staggered and parallel to each other (step 302). Wherein, the exposed area 402 corresponds to the transparent substrate 200 (light-transmitting area) of the exposed portion of the first line / space mask shown in FIG. 2A, and the photoresist area 404 corresponds to that shown in FIG. 2A. The shielding layer 202 (opaque area) of the first line / space mask. After that, the second line / space mask as shown in FIG. 2B is used to repeatedly expose the second image on the negative photoresist of the wafer 400 on which the first pattern has been previously formed (as shown in FIG. 4B) to generate the image as shown in FIG. 4B. The second pattern formed by the laterally exposed regions 406 and the photoresist regions 408 are staggered and parallel to each other as shown in FIG. 4C (step 304). Among them, the exposed area 406 corresponds to the transparent substrate 200 (light-transmitting area) of the exposed portion of the first line / space mask shown in FIG. 2B, and the photoresist area 408 corresponds to FIG. 2B. The shielding layer 204 (opaque area) of the first line / space mask shown. Moreover, since the first pattern and the second pattern after repeated exposure cross each other, the paper size is subject to the Chinese National Standard (CNS) A4 specification (210 ^ 297297f) (Please read the note on the back before filling out this page ) -------- Order · -------- 457548 A7 57l6twf.doc / 008 g7 Five 'invention description (〖C)) is wrong, so that the first pattern and the second pattern are combined with each other and The resulting contact window opening pattern can form a desired contact window opening pattern on the negative photoresist. In other words, the portion where the longitudinal photoresistive region 404 and the lateral photoresistive region 408 are staggered and overlapped is the exposed region 410 of the contact window opening to be formed later. The pitch and size of the line pitch of the first line / pitch mask and the second line / pitch mask depend on the length and width of the contact window opening to be formed. Finally, after developing the negative photoresist having the contact window opening pattern transferred thereon, a grid-shaped photoresist pattern 412 having a contact window opening pattern is formed as shown in FIG. 4D (step 306). The negative photoresist of the exposed area 410 shown in FIG. 4C will be removed to form a contact window opening area 414. The present invention utilizes the linear patterns of two different line / spaced photomasks to stagger one another perpendicularly after repeated exposures to obtain a contact window opening pattern that is combined with each other, thereby forming a desired contact window opening pattern on the negative photoresist layer. And because the line width and size of the first line / spaced photomask and the second line / spaced photomask depend on the length and width of the contact window opening to be formed, and can be arbitrarily adjusted, this method can not only increase the manufacturing process Pre-planned and precisely controlled
I 制線/間距光罩的線距寬，進而得以降低接觸窗開口的關 鍵尺寸。 此外，隨著整個半導體工業的元件積集度增加，其是否 能繼續的往〇·15 μηι以下更小的線寬推進’也決定於微影 製程技術的發展。爲了因應此一需求’一些提高光罩解析 度的方法被不斷地提出來，例如光學鄰近校正法（〇Ptical proximity correction, OPC)、相移式光罩(PSM)、偏軸式照 12 ^紙張尺度適用+园國家標準（CNS)A4規格—x 297公爱） (請先閱讀背面之注意事項再填寫本頁) ^--------訂·-------- 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 457548 A7 5716twf.doc/008 Π7 五、發明說明（丨丨） 明（Off-Axis Illumination，OAI)等。 因此，本發明之線/間距光罩除了可採用習知之方法形 成外，亦可運用強相移式光罩或弱相移式光罩製成，以進 一步提高曝光機的解析度，而降低接觸窗開口的關鍵尺 寸。 另外，由於圖案轉移時所造成的誤差不容忽視，例如在 曝光後的後續製程會因爲圖案轉移所產生之誤差而造成過 度蝕刻、內連線的導通不佳等的結果。故一般在作鄰近式 之圖案轉移時，通常會先將原始圖案經由光學鄰近校正之 後，再將此一經由校正後之圖案作爲光罩圖案。 其中OPC的目的是用以消除因鄰近效應所造成的關鍵 尺寸（critical dimension ; CD)偏差現象。鄰近效應 (proximity effect)是在做光罩圖案的轉移時，影響其投影 在晶片表面上關鍵尺寸準確度最大的因素。此種效應如下 所述，當光束透過光罩上的圖案投影在晶片上時，一方面 由於光束會產生繞射與散射現象而使得光束產生扭曲 (optical distortion)。另一方面，光束會透過晶片表面的光 阻層(ph〇t〇reS1St)經由晶片的基底再反射回來，產生干涉的 現象，因此會重複曝光，而改變在光阻層上實際的曝光量。 此種現象當製程之關鍵尺寸越小時越明顯，尤其當其關 鍵尺寸接近於光源之波長時。 由於投射光所產生的繞射與散射現象，使得光阻角落 處皆被圓弧化了，而且尺寸也被縮小了。另外還有其他 在此未被示出之可能的圖形扭曲，例如當圖案之密度很 13 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） (請先閱讀背面之注意事項再填寫本頁) 訂 ---------4 經濟部智慧財產扃員工消費合作社印製The line pitch of the I-line / pitch reticle is wide, which can reduce the key size of the contact window opening. In addition, with the increase of the component accumulation degree of the entire semiconductor industry, whether it can continue to advance to a line width smaller than 0.15 μm is also determined by the development of lithography process technology. In response to this demand, 'some methods to improve the resolution of the reticle have been continuously proposed, such as optical proximity correction (OPC), phase shift reticle (PSM), off-axis photo 12 ^ paper Applicable scale + National Park Standard (CNS) A4 specification-x 297 public love) (Please read the precautions on the back before filling this page) ^ -------- Order · -------- Economy Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Foreign Affairs Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 457548 A7 5716twf.doc / 008 Π7 5. Description of the invention (丨 丨) (Off-Axis Illumination, OAI) Therefore, in addition to the conventional method, the line / spacing mask can also be made by using a strong phase shift mask or a weak phase shift mask to further improve the resolution of the exposure machine and reduce contact. Key dimensions for window openings. In addition, errors caused by pattern transfer cannot be ignored. For example, subsequent processes after exposure may result in over-etching and poor interconnections due to errors caused by pattern transfer. Therefore, in the case of adjacent pattern transfer, the original pattern is usually corrected by optical proximity, and then the corrected pattern is used as the mask pattern. The purpose of OPC is to eliminate the critical dimension (CD) deviation caused by proximity effects. Proximity effect is the factor that affects the accuracy of the key dimension projection on the wafer surface when transferring the mask pattern. This effect is described below. When a beam is projected on a wafer through a pattern on the reticle, on the one hand, the beam is optically distorted due to diffraction and scattering of the beam. On the other hand, the light beam will pass through the photoresist layer (ph0toS1St) on the surface of the wafer and then be reflected back through the substrate of the wafer, resulting in interference. Therefore, the light will be repeatedly exposed to change the actual exposure on the photoresist layer. This phenomenon becomes more pronounced when the critical size of the process is smaller, especially when its critical size is close to the wavelength of the light source. Due to the diffraction and scattering of the projected light, the corners of the photoresist are rounded and the size is reduced. In addition, there are other possible distortions of the graphics that are not shown here, for example, when the density of the pattern is 13 This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) (Please read the precautions on the back first (Fill in this page again) Order --------- 4 Printed by the Intellectual Property of the Ministry of Economy 扃 Employee Consumer Cooperatives
d 5 7 5 4 C A7 5 7 1 6 t w f . doc/ 〇 〇 8 R7 五、發明說明（丨1) 大時，圖案會融合在一起’或者是圖案之位置可能會因 此偏離原應有之位置。於是一般的補償作法，即在光罩 之遮蔽區的角落或邊緣增加其遮蔽面積以校正圖案扭曲 之處，以獲得近似預想的圖案。 因此，本發明可利用光學鄰近校正法校正兩線/間距光 罩圖案，以獲得更大的製程預度及更精確的圖案。 再者，本發明可以傳統式的照光方式曝光兩線/間距光 罩，亦可以利用偏軸式照明（Off-Axis Illumination, OAI) 的新微影技術曝光兩線/間距光罩。其中，偏軸式照明係 藉著對照射光源入射角度的改進，利用偏斜一較適當的角 度曝光兩線/間距光罩，而可以不需使用新的光源，即可 改善聚焦，進而提高曝光機的解析度，以獲得更精確的圖 案。 綜上所述，本發明的特徵在於利用兩個不同線/間距光 罩之線形圖案於重複曝光後相互交錯垂直，獲得相互組合 而成之接觸窗開口圖案，而得以較簡便的方法在負光阻上 形成所需之接觸窗開口圖形，以及達到縮小接觸窗開口尺 寸的目的。 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) 訂---- 線ί 本紙張尺度適用中國國家標準（CNS>A4規格（210 X 297公釐）d 5 7 5 4 C A7 5 7 1 6 twf. doc / 〇〇8 R7 V. Description of the invention (丨 1) When the pattern is large, the patterns will fuse together 'or the position of the pattern may deviate from its original position . Therefore, the general compensation method is to increase the masking area at the corner or edge of the masked area of the mask to correct the distortion of the pattern to obtain an approximately expected pattern. Therefore, the present invention can use the optical proximity correction method to correct the two-line / pitch mask pattern to obtain a larger process forecast and a more accurate pattern. Furthermore, the present invention can expose a two-line / pitch mask using a conventional illumination method, and can also expose a two-line / pitch mask using a new lithography technology of off-axis illumination (OAI). Among them, off-axis lighting is based on the improvement of the incident angle of the illuminating light source, using a more appropriate angle to expose the two-line / spacing mask, and without using a new light source, the focus can be improved and the exposure can be improved Machine resolution for more accurate patterns. In summary, the present invention is characterized in that the linear patterns of two different line / space photomasks are staggered and perpendicular to each other after repeated exposures to obtain contact window opening patterns that are combined with each other. The required contact window opening pattern is formed on the resistor, and the purpose of reducing the size of the contact window opening is achieved. Although the present invention has been disclosed as above with a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make various modifications and decorations without departing from the spirit and scope of the present invention. The scope of protection of the invention shall be determined by the scope of the attached patent application. (Please read the precautions on the back before filling out this page) Order ---- Thread This paper size applies to Chinese National Standard (CNS > A4 specification (210 X 297 mm)