594375 經濟部智慧財產局員工消費合作社印製 A7 B7 五、發明說明（/) 技術領域： 本發明係關於一種接觸窗光罩的製作方法，特別是關於 一種可解決接觸窗圖案曝光時所產生的各種光學近接現象 (proximity effect)的方法。 發明背景： 在積體電路的製程技術中，必須在晶圓上刻劃各種圖 案，以製備半導體元件，此刻劃圖案的技術便是微影 (lithography)技術，所謂的微影技術是將光罩上的圖案投射到 晶圓上，隨著積體電路的集積密度增加，光罩的解析度就變 得越來越重要，由其是在元件結構日益趨向小型化的今日， 如何準確地製造出所需的光罩圖案以及在晶圓表面曝出光 罩圖案，就變成積體電路工業一個十分重要的課題了。 傳統的光罩製作，係利用電子束在光罩石英基板表面 的鉻(Cr)膜製定出事先設計好的佈局(layout)圖案，然而，考 慮到種種可能的光學誤差來源，此圖案必須作適度的修正， 才能減少設計的佈局(layout)圖案與轉移至晶圓表面圖案的 臨界尺寸偏差(critical dimension variation ; CD variation)。習 知的修正方法僅考慮到微影曝光系統中的光學近接(optical proximity)和光阻(resist proximity)近接現象兩種誤差，並未考 慮到電子束本身的反向散射(back-scattering)現象，如圖一所 示，而導致不同密度的圖案臨界尺寸不均一之現象，此亦即 一般所稱之”電子光束近接效應”(e-beam proximity effect)用 在深次微米接觸窗光罩的製作就不盡理想，可參閱日本的 2 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） -----------裝 ir (請先閱讀背面之注意事項再填寫本頁)594375 Printed by A7 B7, Consumer Cooperatives, Intellectual Property Bureau, Ministry of Economic Affairs V. INTRODUCTION (/) TECHNICAL FIELD: The present invention relates to a method for making a contact window mask, and in particular, to a solution that can be generated when a contact window pattern is exposed. Various methods of optical proximity effect. Background of the Invention: In the integrated circuit manufacturing process technology, various patterns must be scribed on a wafer to prepare a semiconductor element. The pattern engraving technology is lithography. The so-called lithography technology is to convert light to light. The pattern on the mask is projected onto the wafer. As the integration density of the integrated circuit increases, the resolution of the photomask becomes more and more important. How can it be accurately manufactured today when the component structure is increasingly miniaturized? The required mask pattern and the exposure of the mask pattern on the wafer surface have become a very important issue for the integrated circuit industry. Traditional photomask production uses a chromium (Cr) film on the quartz substrate surface of the photomask to develop a pre-designed layout pattern. However, considering various possible sources of optical error, this pattern must be moderate Only in order to reduce the critical dimension variation (CD variation) of the layout pattern of the design and the pattern transferred to the wafer surface. The conventional correction method only considers the two errors of optical proximity and resist proximity in the lithography exposure system, and does not consider the back-scattering phenomenon of the electron beam itself. As shown in Figure 1, the phenomenon of non-uniformity in the critical dimensions of patterns with different densities, which is commonly known as the "e-beam proximity effect" (e-beam proximity effect), is used in the manufacture of sub-micron contact window masks. It ’s not ideal, you can refer to 2 paper sizes in Japan that are applicable to Chinese National Standard (CNS) A4 (210 X 297 mm) ----------- install ir (please read the precautions on the back first) (Fill in this page again)
訂-I s'. 經濟部智慧財產局員工消費合作社印製 594375 A7 B7 五、發明說明（J )Order-I s'. Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 594375 A7 B7 V. Description of the Invention (J)
Murai % A^nra^f?Fast proximity effect correction method using a pattern area density map’’，J· Vac·，Sci·，Technol· B10, 3072 (1992)就提出利用軟體來修正。請參閱圖二，爲一個典 型習知修正方法的流程圖，首先，步驟11是根據接觸窗大 小或是其基準比値(duty ratio ; DR)値的大小不同等影響曝光 的參數’來建立一個所謂的標準曝光環境(standard reticle)， 基準比値(DR)的定義是兩接觸窗之間距B與接觸窗本身尺 寸A的比値，當DR小於一事先選定的基準値時，我們稱此 區爲稠密(dense)接觸窗區’反之則稱爲獨立(isolate)接觸窗 區，基準比値(DR)是影響曝光的一個十分重要的參數。接 著’步驟21是根據標準曝光環境(standard reticle)來尋找出曝 光後的臨界尺寸偏差(CD variation)情形，步驟31則據此來建 立一個合適的光學近接修正(optical proximity correction ; 0PC)模型，然後，步驟41再根據此光學近接修正模型(〇PC model)經過繁複的資料轉換過程將此修正模型的資料變成電 子束在光罩基板表面的軌跡，最後，步驟51才眞正的進行 光罩製作的動作。 傳統的光罩製作流程，其最大的缺點在於步驟41的資 料轉換過程必須搜集龐大的資料，造成了資料轉換過程十分 曠曰費時，同時若是佈局圖案有少許的變動，必須重複整個 流程，不具有彈性，對競爭激烈的半導體工業，造成不小的 困擾。 因此，本發明提出一種修正接觸窗圖案曝光時所產生 的各種近接現象(proximity effect)的新方法，可以解決習知方 3 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） I—---------· 11 —丨丨丨訂！----- (請先閱讀背面之注意事項再填寫本頁) 594375 A7 B7 經濟部智慧財產局員工消費合作社印製 五、發明說明（）） 式的種種缺點。 發明之概述: 本發明之主要目的爲提供一種消弭接觸窗光罩製作時 光學近接現象之方法’係利用一種新的方法來修正接觸窗圖 案曝光時所產生的各種近接現象(Proximity effect)，可以形成 輪廓良好的接觸窗圖案’進而提升積體電路產品的品質和良 率。 本發明之次要目的爲提供一種消弭接觸窗光罩製作時 光學近接現象之方法，可以快速有效地修正接觸窗圖案曝光 時所產生的各種近接現象(proximity effect)，極富有彈性和產 業的實用性，進而大幅減少光罩製作的時間。 本發明之另一目的爲提供一種消弭接觸窗光罩製作時 光學近接現象之方法，可以適用於不同製程臨界尺寸的光罩 製作。 本發明之再一目的爲提供一種消弭接觸窗光罩製作時 光學近接現象之方法，可以適用於不同材質的光罩製作。 本發明係利用以下的方法，來達成上述之各種目的：首 先’是將電路設計(layout)的圖案資料(database)利用電子束 (e-beam)在光罩基板上曝光形成，接著，再進行蝕刻、修整 等光罩製作的過程，最後，再經過檢驗確認光罩是否合乎規 範的標準，如此，即完成光罩的製作了。然後，將光罩上的 圖案利用紫外光等光源曝光轉移至在晶圓表面，即可以得到 4 本紙張尺度適用中國國家標準（CNS)A4規格（21〇 x 297公釐） ----I------— 裝 i — ί·丨—訂--------- (請先閱讀背面之注意事項再填寫本頁) 經濟部智慧財產局員工消費合作社印製 594375 A7 B7 五、發明說明（/) 輪廓良好的接觸窗圖案，本發明所述之消弭接觸窗圖案曝光 時各種光學近接現象之方法於焉完成。 本發明之重點，是在製作光罩時，除了考慮修正電子束 (e-beam)曝光時因電子反向散射(electron back-scattering)所造 成之近接效應(back-scattering)誤差之外，更額外一併修正在 微影時利用紫外光等光源曝光轉移至在晶圓表面時所產生 的光學近接（optical proximity)和光阻近接現象(resist proximity)兩種誤差。能夠大幅提昇光罩製作了準確程度，也 進一步改善了微影後的產品良率。 本發明修正電子束（e-beam)曝光時反向散射 (back-scattering)所造成之近接(proximity)現象的方法，是根 據接觸窗大小或是其基準比値(DR)値的大小不同等影響曝 光的參數，適當的調整電子束強度(e-beam dosage)，即可以 快速地得到較好的接觸窗圖案，而不會有習知方式的缺點。 又因爲光罩的圖案經過微影後轉移至晶圓表面時無可避免 地仍然會有誤差，所以利用電子束強度的過度修正(over correction)，以進一步消弭光學及光阻之近接效應。另一方 面，本發明所使用的光罩材質可以是傳統的二元法光罩 (binary mask ; BIM)或是相位移光罩(phase shift mask; PSM) 均可，用途十分廣泛，具有高度的產業實用性。 圖式簡要說明： 圖一爲習知技藝電子束背面散射對於光阻曝光影響的 不意圖。 5 ------------裝------丨丨訂----- (請先閱讀背面之注意事項再填寫本頁) 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） 594375 經濟部智慧財產局員工消費合作社印製 A7 B7 五、發明說明（ο 圖二爲習知技藝光罩製作的流程圖。 圖三爲本發明實施例光罩製作及微影曝光的流程圖。 圖四爲本發明實施例調整電子束曝光強度來修正電子 反向散射效應的示意圖。 圖五爲利用本發明實施例與習知技藝的光罩所曝出的 接觸窗圖案的比較示意圖。 發明詳細說明: 本發明是有關於光罩製作時一種消弭接觸窗光學接近 現象之方法，在詳細說明中是運用具體實施例說明本發明的 原則與精神。 請參閱圖三，爲本發明實施例的微影流程圖。首先，步 驟201是將電路設計(layout)的圖案資料(database)利用電子 束(e-beam)在光罩基板上曝光形成。接著，步驟2〇3是進行 蝕刻去掉多餘的鉻或是相位移材質以及修整等光罩製作過 程，最後，步驟205再經過檢驗確認光罩是否合乎規範的標 準，如此，即完成光罩的製作了。然後，步驟211是將光罩 上的圖案利用紫外光等光源曝光轉移至在晶圓表面。本發明 所使用的光罩材質可以是傳統的二兀法光罩（binary mask ; BIM)或是相位移光罩(phase shift mask ; PSM)均可。 步驟201是本發明之重點所在，是在製作光罩時，除了 考慮修正電子束(e-beam)曝光時因電子反向散射(back-scattering) 所産生之近接現象 (proximity effect) 誤差之外 ，更額 外一併修正在傳統在步驟211微影時利用紫外光等光源曝光 6 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） ----------I-----訂--------- (請先閱讀背面之注意事項再填寫本頁) 經濟部智慧財產局員工消費合作社印製 594375 A7 B7 五、發明說明（；） 轉移至在晶圓表面時所產生的光學近接(optical proximity)和 光阻近接現象(resist proximity)兩種誤差，如此一來，就能夠 大幅提昇光罩製作了準確程度，也進一步改善了微影後的產 品良率。 所述修正電子束（e-beam)曝光時電子反向散射 (back-scattering)所產生之近接現象的方法，是根據接觸窗大 小或是其基準比値(DR)値的大小不同等來改變曝光的能 量，適當的調整電子束強度(e-beam dosage)，即可以快速地 得到較好的接觸窗圖案，而不會有習知方式的缺點。又因爲 光罩的圖案經過微影後轉移至晶圓表面時無可避免地仍然 會有誤差，所以利用電子束強度的過度修正(over correction)，以進一步得到更佳的功效。 請參閱圖四，爲本發明實施例修正的示意圖，71是未修 正前的圖形，以正常的電子束強度製作光罩，再加上電子反 向散射的效應，會造成光罩上某些區域的過度曝光，以致於 無法獲得理想的圖案；73是修正後的圖形，圖形密度較高者 以較低的電子束強度曝光隨著圖案密度的降低，而漸漸增加 電子束曝光量，再加上電子反向散射的效應，相疊加後即變 成光罩上理想的圖案；75是過度修正後的圖形，圖形密度較 高者以更低的電子束強度曝光，再加上電子反向散射的效 應，相疊加後雖然在光罩上某些區域因曝光量較低導致接觸 窗尺寸較小，但是再次經過微影後轉移光罩的圖案至晶圓表 面時的光學近接(optical proximity)和光阻(resist proximity)近 接現象效應，即變成理想的圖案，完全不會有習知方式的缺 7 -------------裝 ----Γ--訂---- (請先閱讀背面之注意事項再填寫本頁) 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） 594375 A7 B7 五、發明說明（7 ) 點。 (請先閱讀背面之注意事項再填寫本頁) 請參閱圖五，爲臺灣積體電路製造股份有限公司之研發 成果，比較了利用本發明方法和習知方法所製造的光罩，微 影後的晶圓電子顯微鏡相片，可由圖中明顯地看出，利用本 發明方法所製造的光罩，即使是稠密的小接觸窗(dense hole) 圖案，也能得到效果良好的圖形。 最後，再次強調本發明具有以下的優點： 1. 本發明可以大幅增進光罩製作的效率，無論是在修正 接觸窗圖案曝光時所產生的各種近接現象(proximity effect)或是在電子束製作光罩圖案的步驟上，都節省 了許多時間。 2. 本發明的光罩製造方式，可以適用於不同製程臨界尺 寸的光罩製作。 3 ·本發明的光罩製造方式，也可以適用於不同材質(傳統 或是相位移)的光罩製作。 上述說明係以較佳實施例來闡述本發明，而非限制本發 明，並且熟知半導體技藝之人士皆能明瞭，適當而作些微的 經濟部智慧財產局員工消費合作社印製 改變及調整，仍將不失本發明之要義所在，亦不脫離本發明 之精神和範圍。 8 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐）Murai% A ^ nra ^ f? Fast proximity effect correction method using a pattern area density map ’’, J. Vac., Sci., Technol. B10, 3072 (1992) proposed to use software to correct. Please refer to FIG. 2 for a flowchart of a typical conventional correction method. First, step 11 is to establish a parameter that affects exposure based on the size of the contact window or its reference ratio ratio (duty ratio; DR) 等 and other factors that affect exposure. In the so-called standard reticle, the reference ratio DR (DR) is defined as the ratio 距 between the contact window B and the size A of the contact window itself. When DR is less than a pre-selected reference 値, we call this area It is a dense contact window area. Otherwise, it is called an isolate contact window area. The reference ratio DR (DR) is a very important parameter that affects the exposure. Next, step 21 is to find the CD variation after exposure according to the standard exposure environment, and step 31 is to establish a suitable optical proximity correction (0PC) model based on this. Then, in step 41, according to the optical proximity correction model (〇PC model), the data of the correction model is converted into the trajectory of the electron beam on the surface of the photomask substrate through a complicated data conversion process. Finally, in step 51, the photomask is correctly performed. Making action. The biggest disadvantage of the traditional photomask production process is that the data conversion process in step 41 must collect huge data, which makes the data conversion process very time-consuming and meanwhile, if there are slight changes in the layout pattern, the entire process must be repeated. Elasticity has caused considerable distress to the highly competitive semiconductor industry. Therefore, the present invention proposes a new method for correcting various proximity effects generated during exposure of a contact window pattern, which can solve the conventional problem. The paper size is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 mm). ) I —--------- · 11 — 丨 丨 丨 Order! ----- (Please read the notes on the back before filling out this page) 594375 A7 B7 Printed by the Consumers' Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 5. Disclosure of Inventions ()). Summary of the invention: The main purpose of the present invention is to provide a method for eliminating the optical proximity phenomenon during the production of contact window masks. 'A new method is used to correct various proximity effects generated during the exposure of the contact window pattern. Forming a good-profile contact window pattern 'further improves the quality and yield of integrated circuit products. A secondary object of the present invention is to provide a method for eliminating optical proximity phenomenon during the manufacture of a contact window mask, which can quickly and effectively correct various proximity effects generated during exposure of a contact window pattern, which is extremely flexible and industrial. Practicality, further reducing the time required to make the mask. Another object of the present invention is to provide a method for eliminating optical proximity phenomenon during the manufacture of contact window masks, which can be applied to the manufacture of masks with critical dimensions in different processes. Another object of the present invention is to provide a method for eliminating optical proximity phenomenon during the manufacture of contact window masks, which can be applied to the manufacture of masks of different materials. The present invention uses the following methods to achieve the above-mentioned various objectives: first, the pattern database of the circuit layout is formed by exposing an electron beam (e-beam) on a photomask substrate, and then, In the process of making masks such as etching and trimming, at the end, inspection is performed to confirm whether the masks meet the standard standards. In this way, the masks are completed. Then, the pattern on the reticle is exposed and transferred to the surface of the wafer with a light source such as ultraviolet light, and 4 paper sizes can be obtained, which conform to the Chinese National Standard (CNS) A4 specification (21 × x297 mm) ---- I ------— Install i — ί · 丨 —Order --------- (Please read the precautions on the back before filling out this page) Printed by the Intellectual Property Bureau Employee Consumer Cooperative of the Ministry of Economic Affairs 594375 A7 B7 V. Description of the invention (/) A contact window pattern with a good profile, the method for eliminating various optical proximity phenomena when the contact window pattern is exposed according to the present invention is completed. The main point of the present invention is that, in making a photomask, in addition to considering the correction of back-scattering errors caused by electron back-scattering during the e-beam exposure, more importantly, In addition, two errors of optical proximity and resist proximity caused by exposure to light sources such as ultraviolet light during lithography and transferring to the wafer surface are also corrected. It can greatly improve the accuracy of photomask production, and further improve the product yield after lithography. The method for correcting the proximity phenomenon caused by back-scattering during e-beam exposure according to the present invention is based on the size of the contact window or the size of its reference ratio 基准 (DR) 値, etc. The parameters that affect the exposure, and the electron beam intensity (e-beam dosage) can be adjusted appropriately, that is, a better contact window pattern can be obtained quickly without the disadvantages of the conventional method. And because the pattern of the photomask is inevitably still error when it is transferred to the wafer surface after lithography, the over correction of the intensity of the electron beam is used to further eliminate the close effects of optics and photoresist. On the other hand, the material of the photomask used in the present invention may be a traditional binary mask (BIM) or a phase shift mask (PSM). Industrial applicability. Brief description of the drawings: Figure 1 is the unintended effect of the backscattering of the electron beam on photoresist exposure in the conventional art. 5 ------------ Installation ------ 丨 丨 Order ----- (Please read the precautions on the back before filling out this page) This paper size applies to Chinese national standards (CNS ) A4 size (210 X 297 mm) 594375 A7 B7 printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 5. Description of the invention (ο Figure 2 is a flow chart of the production of masks of conventional techniques. Figure 3 Flow chart of mask making and lithographic exposure. Fig. 4 is a schematic diagram of adjusting the electron back exposure effect to modify the electron backscattering effect according to the embodiment of the present invention. Fig. 5 is a photomask exposed by using the embodiment and the conventional technique of the present invention Comparative schematic diagram of the contact window pattern. Detailed description of the invention: The present invention relates to a method for eliminating the optical proximity phenomenon of the contact window during the manufacture of a photomask. In the detailed description, specific embodiments are used to explain the principles and spirit of the present invention. FIG. 3 is a lithography flowchart according to an embodiment of the present invention. First, step 201 is to form a pattern database of a circuit layout by using an electron beam (e-beam) on a photomask substrate. Next, step 〇3 is to etch away Excess chrome or phase shift material and trimming process such as trimming. Finally, step 205 is checked to confirm whether the mask conforms to the standard. In this way, the mask is completed. Then, step 211 is to mask the mask. The pattern on the wafer is exposed and transferred to the surface of the wafer using a light source such as ultraviolet light. The mask material used in the present invention may be a traditional binary mask (BIM) or a phase shift mask (phase shift mask; (PSM). Step 201 is the focus of the present invention. In making a photomask, in addition to considering the correction of electron beam (e-beam) exposure due to electron back-scattering (proximity) effect) In addition to the error, an additional correction has been made in the traditional exposure using ultraviolet light and other light sources in step 211 lithography. 6 This paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) ------ ---- I ----- Order --------- (Please read the notes on the back before filling out this page) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 594375 A7 B7 V. Description of the invention (;) When transferred to the wafer surface The two errors of optical proximity and resist proximity are generated, so that the accuracy of photomask production can be greatly improved, and the product yield after lithography is further improved. The close-up phenomenon caused by electron back-scattering during e-beam exposure is to change the exposure energy according to the size of the contact window or the size of its reference ratio 値 (DR) 値. By properly adjusting the e-beam dosage, a better contact window pattern can be obtained quickly without the disadvantages of the conventional method. Because the pattern of the photomask is inevitably still inaccurate when transferred to the wafer surface after lithography, an over correction of the intensity of the electron beam is used to further obtain better efficiency. Please refer to FIG. 4, which is a schematic diagram of a modification of the embodiment of the present invention. 71 is a figure before modification. A photomask is made with normal electron beam intensity. In addition, the effect of electron backscattering will cause some areas on the photomask. Over-exposure, so that the ideal pattern cannot be obtained; 73 is the corrected pattern. The higher the pattern density, the lower the electron beam intensity exposure is. As the pattern density decreases, the electron beam exposure is gradually increased, plus The effect of electron backscatter, when superimposed, becomes the ideal pattern on the photomask; 75 is an over-corrected figure. The higher the pattern density is, the lower the electron beam intensity is exposed, plus the effect of electron backscatter. After the superposition, although the contact window size is smaller in some areas of the photomask due to the lower exposure, the optical proximity and photoresistance when the pattern of the photomask is transferred to the wafer surface after lithography again resist proximity) The effect of proximity phenomenon, that is, it becomes an ideal pattern, and there is no lack of conventional methods. 7 ------------- 装 ---- Γ--Order ---- ( Please read the notes on the back first (Fill in this page) The size of this paper applies to the Chinese National Standard (CNS) A4 (210 X 297 mm) 594375 A7 B7 V. Description of the invention (7). (Please read the precautions on the back before filling this page) Please refer to Figure 5 for the research and development results of Taiwan Semiconductor Manufacturing Co., Ltd., comparing the photomasks manufactured by the method of the present invention and the conventional method. From the picture of the wafer electron microscope, it can be clearly seen from the figure that even if the photomask manufactured by the method of the present invention is a dense small dense hole pattern, a good effect pattern can be obtained. Finally, it is emphasized once again that the present invention has the following advantages: 1. The present invention can greatly improve the efficiency of photomask production, whether it is to correct various proximity effects generated during the exposure of the contact window pattern or to produce light in the electron beam Steps in the mask pattern have saved a lot of time. 2. The manufacturing method of the photomask of the present invention can be applied to the production of photomasks of different critical sizes. 3. The photomask manufacturing method of the present invention can also be applied to photomasks made of different materials (traditional or phase shifted). The above description is to illustrate the present invention with a preferred embodiment, but not to limit the present invention. Those skilled in the art of semiconductors will be able to understand it. Appropriate and minor changes to the printing and adjustment of the employee consumer cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs will still Without departing from the spirit of the invention, and without departing from the spirit and scope of the invention. 8 This paper size applies to China National Standard (CNS) A4 (210 X 297 mm)