200839174 九、發明說明·· 【發明所屬之技術領域】 :::係關於一種對微影光罩上之結構的測量裝置。此 二：：至/一個發出相干光的照射源，其係經由照射 y置/Γ μ射微影光罩；—個收納微影光罩的空間上可 :成傻:ί ’其位置係藉由雷射干涉量測而受到控制；一 衣置’將來自於微影光罩的光成像於 f. -個輕接至辕置的評估裝置，而該評估裝置評 估所偵測到的信號，並判定諸結構之位置。 【先前技術】 命片之生產中’已有在相同表面區域上產生愈來 =、、、。構的傾向。此等晶片目前係由大約30個不同的 層所組成。功能結構（即，所謂的「特徵」）之大小為 、、、、 11111必須生產具有相應高精度的用於生產 i的微影先罩。為此目的，晶圓被曝光多達3。二= =層而要不同光罩。因此，一方面需要極精確的光罩生 而另#面則需要極精確的定位，以使得諸層彼此準 石對準。關於被重疊的諸層’對於最新應用而言，必須達 成广8 nm之知度。此為通常具有15〇咖之側面長度的光 罩彼此對準4所必須具有的精度。因此，在相關於參考座 標的諸正確位置處（例如，光罩諸角落其中-者），產生將 形成為光罩的基板中之光罩結構，為至關重要的。 為了叩貝控制，將稱之為標記的結構（例如，光罩上具 有1〇"Xl〇"m尺寸、及1㈣筆劃寬度(stroke Wldth; 96144910 200839174 的十字形）加於光罩上。所謂的「配準工具」（registrati〇n tool)接著分析此等結構是否在可允許的容許度内被定位 於恰當位置處。此一裝置為（例如）來自Vistec corporation之IPR03。此裝置在365 _之波長下操作。 然而’藉此可達成的精度對於將來的結構仍不夠高。 在光罩中分別待測量的結構或標記通常為類似的型 式，以確保比較及再生產為可能。因此，系統錯誤對結構 p亦應具有類似效應。舉例而言，所使用的結構可為十字， 其具有具10 //m長度及1 寬度的線條。接著在光罩 上產生100個與400個之間的此等十字。十字通常被定位 於不具有晶圓曝光所需結構的區域中，使得此等結構中之 母一者之附近區域通常顯現為相同。 然而，將來所需的應用將准許用於彼此定位並對準光罩 的至多4· 8 nm之精度。不僅必須合適地定位光罩，而且 必須合適地定位待曝光的晶圓。然而，在對光罩之寫入以 〇及對光罩及控制標記之測量期間，可能會出現導致諸結構 位置上多達10 nra之觀測偏差的效應；然而，此係在所允 許的容許度範圍外。此等效應一方面係由在使用電子束寫 入器寫入光罩期間可能發生的光罩之所謂的「充電效應」 所導致。此充電效應對用於品質控制的待測量結構之影 響，極大地取決於光罩上結構之相鄰區域。此等充電效應 導致結構不被寫入為此目的而提供的位置，而是寫入在偏 離該位置若干奈米的位置。 此外，結構之成像可能受到可能在「配準工具」中發生 96144910 7 200839174 的散射光效應之影響。偵測之偏差具有與充電效應之偏差 類似的數量級。然而，與後者形成相對比，經散射的光效 -應僅導致結構圖像之偏移，但不會導致結構自身之偏移。 因此’其結構僅外觀上為偏移。 在先則技術中，無法將此二效應相互區分開，到目前尚 未產生任何重要影響，因為1〇nm之精度已為足夠。缺而， 將來的應用將需要較高精度。然而，在先前技術中已知之 尚無法判定是存在歸因於散射光效應的外觀偏移， 、逛是由充電效應所導致的實際偏移。在後一狀況下，必須 改變電子束寫入器之設定。 【發明内容】 口此本赉明之目標為改良對微影光罩上之結構的測量 裝置’使得上述諸效應可被區分。 藉由在照射光束路徑中設置至彡一個場擔才反，而在上述 2型的用於測量微影光罩上之結構的裝置中達成此目 ，軚忒場擋板具有對應於在光罩上成像之期間圍繞著一結 構之區域的大小，而該區域對於所有的結構顯現為等同。 口此，僅知射到此一圍繞著光罩的區域。以此方式，抑制 了可此歸因於不同相鄰區域而呈不同的散射光效應。在邊 =情況下，圍繞著一結構的區域係對應於仍含有此結構的 最小可能區域。對於十字狀標記，此區域可為（例如）正方 7、圓形、或亦為十字。阻斷散射光效應，使其可以區分 疋存在外觀偏移、還是實際偏移：若在使用場擋板來測量 之J間隹生結構偏移，則會出現充電效應。此偏移將接著 96144910 8 200839174 亦會在不使用場擋板情況下顯現，且，電子束寫入器必須 被適當地調整。然而，若偏移僅在不使用場擋板狀況下顯 現’則可假定是由散射光效應導致偏移。在此狀況下，將 不需要改變電子束寫入器之設定。 ά亥至少一個場擋板較佳為可互換的，從而允許適應於不 同的結構、不同的結構大小、以及不同的成像比。亦可藉 由對該至少一個場擋板而可變地調整被照射的場之大 小，而達成此目標。 【實施方式】 以下藉由例示性具體例更詳細解釋本發明。 在圖1中所示之裝置中，微影光罩丨被支撐於台座2上 之:個載體上。在三個空間方向上皆可移動台座2。為確 ，高精度，藉由未圖示之雷射干涉量測裝置，分別地監視 貝IV、位置或路徑長度差。水平地（亦即，垂直於重力作用） 排列微影光罩1及台座2。第-照射源3(例如，發射193 nm波長光的雷射）被配置於具有微影光罩}的台座2上 方:經，由第一照射光束路徑4，將光導向於微影光罩工上， 而該第-照射光束路徑4僅包括透鏡及/或鏡面。第一昭 射源3及第-照射光束路徑以作為藉由所透射的光以= 射微影光罩卜如透鏡5及6所表現，照射光束路徑4可 被設置f為完全自由的光束路徑。在台座2之另-側，設 有包含第二照射光束路徑8的第二照射源7，如由透鏡9 表：第,照射光束路徑8亦可被設置成為完全 、一路徑。第二照射源及第二照射光束路徑用作為 96144910 9 200839174 藉由入射光來檢查微影光罩i。來自於微影光罩】的光（直 係為透射通過微影光罩i或由微影光罩）所反射 ， ㈣成像光學元件11及半透射鏡面12,而成像於空間上 解析的偵測裝f 13上，其亦可被設計成為⑽相機。在 後:種情況中，所_到的強度被轉換為電信號，且傳輸 至評估單元14。 藉由此種配置，將定位於微影光罩i上且用於品»制 ^途的結構成像於仙器、13上。藉由干涉量測所判^的 微影光罩1之位置’足以導出微影光罩i上之結構之位 置。照射及成像兩者用的光束路徑較佳為平行於重力，因 此僅會在軸向方向讓透鏡及其固定件受到重力作用，如此 顯著地增加了光束導向之精度。 此外，在照射光束路徑4及/或在照射光束路徑8 分別設有場擋板15或16。場檔板15及16係用來調整照 =於微影光罩1上的場之大小’使得，僅照射到最小的; (能區域（其係在成像期間對於全部通常為類似的結構顯現 為等同）。以此方式，可抑制由用於進行標記的結構之' 鄰區域所導致的散射光效應。如此可以分別判定在微影光 罩1之圖像、或為了品質控制而加諸的結構之圖像中為可 ^的、且係關於所要位置的偏移，究竟是由散射光效應°、 還是由充電效應導致。該場擋板可為可互換及/或可變 調整，使其可適應於不同的結構大小及/或圖像比。 【圖式簡單說明】 圖1展不根據本發明之裝置的基本結構。 96144910 200839174 【主要元件符號說明】 1 微影光罩 2 台座 3 (第一）照射源 4 (第一）照射光束路徑 5、6 透鏡 7 (第二）照射源 8 (第二）照射光束路徑 f 9、10 透鏡 11 成像光學元件 12 半透射鏡面 13 偵測裝置；偵測器 14 評估單元；評估裝置 1 5、16場擋板 96144910 11200839174 IX. INSTRUCTIONS··· TECHNICAL FIELD OF THE INVENTION::: A measuring device for a structure on a lithographic mask. The second:: to / an illuminating source that emits coherent light, which is irradiated by y Γ Γ Γ 射 微 ; ; ; ; — — — — 收纳 收纳 收纳 收纳 收纳 收纳 收纳 收纳 收纳 收纳 收纳 收纳 收纳 收纳 收纳 收纳 收纳 收纳 收纳 收纳 收纳 收纳 收纳 ί Controlled by laser interference measurement; a garment is placed to image the light from the lithography reticle to an evaluation device that is lightly connected to the device, and the evaluation device evaluates the detected signal, And determine the location of the structures. [Prior Art] In the production of film, 'there has been an increase in the same surface area =, , , . The tendency of construction. These wafers are currently composed of approximately 30 different layers. The size of the functional structure (i.e., the so-called "feature") of , , , 11111 must produce a lithographic mask for production i with corresponding high precision. For this purpose, the wafer is exposed up to three. Two = = layer and different masks. Therefore, on the one hand, an extremely precise mask is required, while the other side requires extremely precise positioning so that the layers are aligned with each other. With regard to the layers that are overlapped, for the latest applications, it is necessary to reach a level of 8 nm. This is the precision that the reticle, which typically has a side length of 15 ounces, must be aligned with each other 4 . Therefore, it is critical to create a reticle structure in the substrate that will be formed into a reticle at the correct locations associated with the reference coordinates (e.g., among the corners of the reticle). For mussel control, a structure called a mark (for example, a mask having a 〇"Xl〇"m size, and a 1 (four) stroke width (cross shape of stroke Wldth; 96144910 200839174) is applied to the reticle. The so-called "registrati" tool then analyzes whether these structures are located at the appropriate locations within the allowable tolerance. This device is, for example, IPR03 from the Vistec corporation. This device is at 365 Operating at the wavelength of _. However, the accuracy that can be achieved is still not high enough for future structures. The structures or marks to be measured in the reticle are usually of a similar type to ensure comparison and reproduction. Therefore, the system The error should have a similar effect on the structure p. For example, the structure used can be a cross with lines having a length of 10 // m and a width of 1. Then between 100 and 400 on the reticle Such crosses. The cross is typically positioned in a region that does not have the structure required for wafer exposure, such that the vicinity of the parent in such structures typically appears to be the same. The application will permit an accuracy of up to 4.8 nm for positioning and aligning the reticle with each other. Not only must the reticle be properly positioned, but the wafer to be exposed must be properly positioned. However, writing to the reticle During the measurement of the reticle and the control mark, there may be an effect of observing deviations of up to 10 nra at various structural locations; however, this is outside the allowable tolerance range. Caused by the so-called "charging effect" of the reticle that may occur during writing of the reticle using the electron beam writer. The effect of this charging effect on the structure to be measured for quality control depends greatly on the reticle Adjacent areas of the structure. These charging effects cause the structure to not be written to the location provided for this purpose, but rather to a position offset from the position by a few nanometers. Furthermore, the imaging of the structure may be subject to possible registration The effect of the scattered light effect of 96194940 7 200839174 occurs in the tool. The deviation of the detection has an order of magnitude similar to the deviation of the charging effect. However, in contrast to the latter, the dispersion The light effect of the shot - should only result in a shift in the structural image, but does not cause the structure itself to shift. Therefore, its structure is only offset in appearance. In the prior art, the two effects cannot be distinguished from each other. There has not been any significant impact so far, because the accuracy of 1 〇 nm is sufficient. In the future, future applications will require higher precision. However, it is known in the prior art that it is not possible to determine the existence due to the scattered light effect. The appearance of the offset, the wandering is the actual offset caused by the charging effect. In the latter case, the setting of the electron beam writer must be changed. [Summary of the Invention] The goal of this book is to improve the lithography The measuring device of the structure on the cover makes the above effects distinguishable. This is achieved in the apparatus for measuring the structure on the lithographic reticle by setting the path to the field in the illumination beam path, and the field baffle has a corresponding mask. The upper imaging period revolves around the size of the area of a structure that appears to be equivalent for all structures. This is the only way to see this area around the reticle. In this way, different scattered light effects that can be attributed to different adjacent regions are suppressed. In the case of edge =, the area surrounding a structure corresponds to the smallest possible area that still contains this structure. For cross-shaped marks, this area can be, for example, square 7, round, or also a cross. The effect of the scattered light is blocked so that it can distinguish between the presence or absence of an apparent shift or the actual offset: if the field buckling is used to measure the J-parallel structure offset, a charging effect will occur. This offset will then appear on 96144910 8 200839174 without the use of a field stop, and the beam writer must be properly adjusted. However, if the offset appears only if the field baffle is not used, then it can be assumed that the offset is caused by the scattered light effect. In this case, there is no need to change the settings of the electron beam writer. At least one of the field baffles is preferably interchangeable, allowing for adaptation to different structures, different structural sizes, and different imaging ratios. This goal can also be achieved by variably adjusting the size of the illuminated field to the at least one field baffle. [Embodiment] Hereinafter, the present invention will be explained in more detail by way of illustrative specific examples. In the apparatus shown in Fig. 1, the reticle mask is supported on a carrier on the pedestal 2. The pedestal 2 can be moved in all three spatial directions. To ensure accuracy and high precision, the Bay IV, position or path length difference is monitored separately by a laser interference measuring device (not shown). The reticle reticle 1 and the pedestal 2 are arranged horizontally (i.e., perpendicular to gravity). The first-illumination source 3 (for example, a laser that emits light of 193 nm wavelength) is disposed above the pedestal 2 having a lithography mask: via the first illumination beam path 4, directing the light to the lithography reticle Above, the first illumination beam path 4 includes only lenses and/or mirrors. The first source 3 and the first-illuminated beam path are represented by the transmitted light by the lithography masks such as the lenses 5 and 6, and the illumination beam path 4 can be set to f to a completely free beam path. . On the other side of the pedestal 2, a second illumination source 7 comprising a second illumination beam path 8 is provided, as indicated by the lens 9: the illumination beam path 8 can also be set to a complete, one path. The second illumination source and the second illumination beam path are used as 96144910 9 200839174 to inspect the reticle illuminator i by incident light. The light from the lithography mask (directly transmitted through the lithography mask i or by the lithography mask), (4) the imaging optical element 11 and the semi-transmissive mirror surface 12, and the imaging is spatially resolved. On the f 13 , it can also be designed as a (10) camera. In the latter case, the intensity of the _ is converted to an electrical signal and transmitted to the evaluation unit 14. With this configuration, the structure positioned on the lithography mask i and used for the manufacturing process is imaged on the fairy, 13. The position of the reticle reticle 1 judged by the interference measurement is sufficient to derive the position of the structure on the reticle reticle i. The beam path for both illumination and imaging is preferably parallel to gravity, so that the lens and its fixture are only subjected to gravity in the axial direction, thus significantly increasing the accuracy of beam steering. Furthermore, field baffles 15 or 16 are provided in the illumination beam path 4 and/or in the illumination beam path 8, respectively. The field baffles 15 and 16 are used to adjust the size of the field on the lithographic mask 1 such that only the minimum illumination is achieved; (the energy region (which is visualized for all of the generally similar structures during imaging) Equivalent) In this way, the scattered light effect caused by the 'neighboring region of the structure for marking can be suppressed. Thus, the image of the reticle reticle 1 or the structure added for quality control can be determined separately. The offset in the image is related to the desired position, whether it is caused by the scattered light effect or by the charging effect. The field baffle can be interchangeable and / or variable adjustment, making it Adapted to different structural sizes and/or image ratios. [Simplified illustration of the drawings] Figure 1 shows the basic structure of a device not according to the present invention. 96144910 200839174 [Signature of main components] 1 lithography mask 2 pedestal 3 (No. a) illumination source 4 (first) illumination beam path 5, 6 lens 7 (second) illumination source 8 (second) illumination beam path f 9, 10 lens 11 imaging optics 12 semi-transmissive mirror 13 detection device; Measurer 14 evaluation unit; 5,16 field baffle means 1 9614491011