本發明係關於可用於(例如)藉由微影技術來製造器件之度量衡方法，且係關於使用微影技術來製造器件之方法。The present invention relates to a metrology method that can be used, for example, to fabricate devices by lithography, and is directed to methods of fabricating devices using lithography.
本申請案主張2007年12月27日申請且全文以引用之方式併入本文中之美國臨時申請案61/009,192的益處。The present application claims the benefit of U.S. Provisional Application No. 61/009,192, filed on Dec. 27, 2007, which is hereby incorporated by reference.
微影裝置為將所要圖案施加至基板上(通常施加至基板之目標部分上)的機器。微影裝置可用於(例如)積體電路(IC)之製造中。在該情況下，圖案化器件(其或者被稱作光罩或主光罩)可用以產生待形成於IC之個別層上的電路圖案。可將此圖案轉印至基板(例如，矽晶圓)上之目標部分(例如，包含晶粒之一部分、一個晶粒或若干晶粒)上。圖案之轉印通常係經由成像至提供於基板上之輻射敏感材料(抗蝕劑)層上。一般而言，單一基板將含有經順次圖案化之鄰近目標部分的網路。已知微影裝置包括：所謂的步進器，其中藉由一次性將整個圖案曝光至目標部分上來照射每一目標部分；及所謂的掃描器，其中藉由在給定方向("掃描"方向)上經由輻射光束而掃描圖案同時平行或反平行於此方向而同步地掃描基板來照射每一目標部分。亦有可能藉由將圖案壓印至基板上而將圖案自圖案化器件轉印至基板。A lithography apparatus is a machine that applies a desired pattern onto a substrate, typically applied to a target portion of the substrate. The lithography apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In this case, a patterned device (which may alternatively be referred to as a reticle or main reticle) may be used to create a circuit pattern to be formed on individual layers of the IC. This pattern can be transferred onto a target portion (eg, including a portion of a die, a die, or a plurality of dies) on a substrate (eg, a germanium wafer). Transfer of the pattern is typically via imaging onto a layer of radiation-sensitive material (resist) provided on the substrate. In general, a single substrate will contain a network of sequentially patterned adjacent target portions. Known lithography apparatus includes a so-called stepper in which each target portion is illuminated by exposing the entire pattern to a target portion at a time; and a so-called scanner in which a direction is given in a "scan" direction Each of the target portions is illuminated by scanning the substrate simultaneously via the radiation beam while scanning the substrate in parallel or anti-parallel to this direction. It is also possible to transfer the pattern from the patterned device to the substrate by imprinting the pattern onto the substrate.
為了監控微影過程，應測量經圖案化基板之參數，例如，形成於基板中或基板上之順次層之間的疊對誤差。存在用於進行微影過程中所形成之顯微結構之測量的各種技術，包括掃描電子顯微鏡及各種專門工具之使用。一專門度量衡工具形式為散射計，其中將輻射光束引導至基板之表面上之目標上，且測量經散射或經反射光束之特性。藉由比較光束在其已由基板反射或散射之前與之後的特性，可判定基板之特性。此可(例如)藉由比較經反射光束與儲存於與已知基板特性相關聯之已知測量庫中的資料來進行。已知兩種主要類型之散射計。分光散射計將寬頻帶輻射光束引導至基板上，且測量散射至特定窄角範圍中之輻射的光譜(作為波長之函數的強度)。角度解析散射計順次或並行地使用單色輻射光束，且測量經散射輻射之作為角度之函數的強度。In order to monitor the lithography process, parameters of the patterned substrate, such as stacking errors between successive layers formed in or on the substrate, should be measured. There are various techniques for performing measurements of microstructures formed during lithography, including the use of scanning electron microscopes and various specialized tools. A specialized metrology tool is in the form of a scatterometer in which a beam of radiation is directed onto a target on the surface of the substrate and the characteristics of the scattered or reflected beam are measured. The characteristics of the substrate can be determined by comparing the characteristics of the beam before and after it has been reflected or scattered by the substrate. This can be done, for example, by comparing the reflected beam to data stored in a known measurement library associated with known substrate characteristics. Two main types of scatterometers are known. A spectroradiometer directs the broadband radiation beam onto the substrate and measures the spectrum of the radiation scattered into a particular narrow angle range (intensity as a function of wavelength). The angle resolved scatterometer uses a monochromatic radiation beam in sequence or in parallel and measures the intensity of the scattered radiation as a function of angle.
對於對基板之應測量積體電路之後續層的部分內部之目標之疊對測量(所謂的晶粒內測量(in-die measurement))，與當前使用之30x30μm、40x40μm或類似切割道標號器相比，應進一步減少目標之尺寸。For the measurement of the overlap of the target inside the portion of the substrate to which the subsequent layer of the integrated circuit should be measured (so-called in-die measurement), with the currently used 30x30μm, 40x40μm or similar scriber marker The size of the target should be further reduced.
需要提供一種實現對更小及更大目標之測量(例如，在切割道區域以及切割道區域中之更大標號器外部的晶粒內測量)的度量衡裝置。There is a need to provide a metrology device that enables measurements of smaller and larger targets (eg, intra-grain measurements outside the larger marker in the scribe lane region and the scribe lane region).
根據本發明之一態樣，提供一種經組態以測量基板之特性的度量衡裝置。度量衡裝置包括：照明系統，照明系統經組態以調節輻射光束；接物鏡，接物鏡經組態以將輻射投影至基板上；偵測器，偵測器經組態以偵測自基板之表面所反射的輻射；及影像場選擇器件，影像場選擇器件在經反射輻射之路徑中，影像場選擇器件經建構及配置以選擇與基板相關聯之影像場的區域。選定區域與基板之預定部分對應。In accordance with an aspect of the present invention, a metrology apparatus configured to measure characteristics of a substrate is provided. The metrology apparatus includes: an illumination system configured to adjust a radiation beam; an objective lens, the objective lens configured to project radiation onto the substrate; the detector, the detector configured to detect the surface of the substrate The reflected radiation; and the image field selection device, the image field selection device in the path of the reflected radiation, the image field selection device is constructed and configured to select an area of the image field associated with the substrate. The selected area corresponds to a predetermined portion of the substrate.
根據本發明之一態樣，提供一種包括經組態以測量基板之特性之度量衡裝置的微影裝置。度量衡裝置包括：照明系統，照明系統經組態以調節輻射光束；接物鏡，接物鏡經組態以將輻射投影至基板上；偵測器，偵測器經組態以偵測自基板之表面所反射的輻射；及影像場選擇器件，影像場選擇器件在經反射輻射之路徑中，影像場選擇器件經建構及配置以選擇與基板相關聯之影像場的區域。選定區域與基板之預定部分對應。In accordance with an aspect of the present invention, a lithography apparatus including a metrology apparatus configured to measure characteristics of a substrate is provided. The metrology apparatus includes: an illumination system configured to adjust a radiation beam; an objective lens, the objective lens configured to project radiation onto the substrate; the detector, the detector configured to detect the surface of the substrate The reflected radiation; and the image field selection device, the image field selection device in the path of the reflected radiation, the image field selection device is constructed and configured to select an area of the image field associated with the substrate. The selected area corresponds to a predetermined portion of the substrate.
根據本發明之另一態樣，提供一種測量基板之特性的方法。方法包括：將輻射投影至基板上；及偵測自基板所反射之輻射。經反射輻射指示待測量之特性。方法亦包括：使影像場與基板相關聯；及選擇影像場之與基板之預定部分對應的部分以用於自基板之對應部分偵測經反射輻射。According to another aspect of the present invention, a method of measuring characteristics of a substrate is provided. The method includes: projecting radiation onto the substrate; and detecting radiation reflected from the substrate. The reflected radiation indicates the characteristic to be measured. The method also includes: associating the image field with the substrate; and selecting a portion of the image field corresponding to the predetermined portion of the substrate for detecting reflected radiation from a corresponding portion of the substrate.
現將參看隨附示意性圖式而僅藉由實例來描述本發明之實施例，在該等圖式中，對應參考符號指示對應部分。Embodiments of the present invention will be described by way of example only with reference to the accompanying drawings, in which
圖1示意性地描繪微影裝置。裝置包含：照明系統(照明器)IL，其經組態以調節輻射光束B(例如，UV輻射或DUV輻射)；支撐結構(例如，光罩台)MT，其經建構以支撐圖案化器件(例如，光罩)MA且連接至經組態以根據某些參數來精確地定位圖案化器件之第一定位器PM；基板台(例如，晶圓台)WT，其經建構以固持基板(例如，塗覆抗蝕劑之晶圓)W且連接至經組態以根據某些參數來精確地定位基板之第二定位器PW；及投影系統(例如，折射投影透鏡系統)PL，其經組態以將由圖案化器件MA賦予至輻射光束B之圖案投影至基板W之目標部分C(例如，包含一或多個晶粒)上。Figure 1 schematically depicts a lithography apparatus. The apparatus includes an illumination system (illuminator) IL configured to condition a radiation beam B (eg, UV radiation or DUV radiation), and a support structure (eg, a reticle stage) MT configured to support the patterned device ( For example, the reticle) MA is coupled to a first locator PM configured to accurately position the patterned device according to certain parameters; a substrate stage (eg, wafer table) WT that is configured to hold the substrate (eg, a resist-coated wafer) and coupled to a second locator PW configured to accurately position the substrate according to certain parameters; and a projection system (eg, a refractive projection lens system) PL, grouped The state is projected onto the target portion C (e.g., comprising one or more dies) of the substrate W by the pattern imparted by the patterned device MA to the radiation beam B.
照明系統可包括用於引導、成形或控制輻射之各種類型的光學組件，諸如，折射、反射、磁性、電磁、靜電或其他類型的光學組件，或其任何組合。The illumination system can include various types of optical components for guiding, shaping, or controlling radiation, such as refractive, reflective, magnetic, electromagnetic, electrostatic, or other types of optical components, or any combination thereof.
支撐結構支撐(亦即，承載)圖案化器件。支撐結構以視圖案化器件之定向、微影裝置之設計及其他條件(諸如，圖案化器件是否固持於真空環境中)而定的方式來固持圖案化器件。支撐結構可使用機械、真空、靜電或其他夾持技術來固持圖案化器件。支撐結構可為(例如)框架或台，其可根據需要而為固定或可移動的。支撐結構可確保圖案化器件(例如)相對於投影系統而處於所要位置。可認為本文對術語"主光罩"或"光罩"之任何使用均與更通用之術語"圖案化器件"同義。The support structure supports (ie, carries) the patterned device. The support structure holds the patterned device in a manner that depends on the orientation of the patterned device, the design of the lithographic device, and other conditions, such as whether the patterned device is held in a vacuum environment. The support structure can hold the patterned device using mechanical, vacuum, electrostatic or other clamping techniques. The support structure can be, for example, a frame or table that can be fixed or movable as desired. The support structure ensures that the patterned device, for example, is in a desired position relative to the projection system. Any use of the term "main reticle" or "reticle" herein is considered synonymous with the more general term "patterned device."
本文所使用之術語"圖案化器件"應被廣泛地解釋為指代可用以在輻射光束之橫截面中向輻射光束賦予圖案以便在基板之目標部分中形成圖案的任何器件。應注意，例如，若被賦予至輻射光束之圖案包括相移特徵或所謂的輔助特徵，則圖案可能不會精確地對應於基板之目標部分中的所要圖案。通常，被賦予至輻射光束之圖案將對應於目標部分中所形成之器件(諸如，積體電路)中的特定功能層。The term "patterned device" as used herein shall be interpreted broadly to refer to any device that can be used to impart a pattern to a radiation beam in a cross-section of a radiation beam to form a pattern in a target portion of the substrate. It should be noted that, for example, if the pattern imparted to the radiation beam includes a phase shifting feature or a so-called auxiliary feature, the pattern may not exactly correspond to the desired pattern in the target portion of the substrate. Typically, the pattern imparted to the radiation beam will correspond to a particular functional layer in a device (such as an integrated circuit) formed in the target portion.
圖案化器件可為透射或反射的。圖案化器件之實例包括光罩、可程式化鏡面陣列，及可程式化LCD面板。光罩在微影術中為熟知的，且包括諸如二元交變相移及衰減相移之光罩類型，以及各種混合光罩類型。可程式化鏡面陣列之一實例使用小鏡面之矩陣配置，該等小鏡面中之每一者可個別地傾斜，以便在不同方向上反射入射輻射光束。傾斜鏡面將圖案賦予於由鏡面矩陣所反射之輻射光束中。The patterned device can be transmissive or reflective. Examples of patterned devices include photomasks, programmable mirror arrays, and programmable LCD panels. Photomasks are well known in lithography and include reticle types such as binary alternating phase shift and attenuated phase shift, as well as various hybrid reticle types. One example of a programmable mirror array uses a matrix configuration of small mirrors, each of which can be individually tilted to reflect the incident radiation beam in different directions. The tilted mirror imparts a pattern to the radiation beam reflected by the mirror matrix.
本文所使用之術語"投影系統"應被廣泛地解釋為涵蓋任何類型之投影系統，包括折射、反射、反射折射、磁性、電磁及靜電光學系統或其任何組合，其適合於所使用之曝光輻射，或適合於諸如浸沒液體之使用或真空之使用的其他因素。可認為本文對術語"投影透鏡"之任何使用均與更通用之術語"投影系統"同義。The term "projection system" as used herein shall be interpreted broadly to encompass any type of projection system, including refractive, reflective, catadioptric, magnetic, electromagnetic, and electrostatic optical systems, or any combination thereof, suitable for the exposure radiation used. Or suitable for other factors such as the use of immersion liquids or the use of vacuum. Any use of the term "projection lens" herein is considered synonymous with the more general term "projection system."
如此處所描繪，裝置為透射類型(例如，使用透射光罩)。或者，裝置可為反射類型(例如，使用如以上所提及之類型的可程式化鏡面陣列，或使用反射光罩)。As depicted herein, the device is of the transmissive type (eg, using a transmissive reticle). Alternatively, the device can be of the reflective type (eg, using a programmable mirror array of the type mentioned above, or using a reflective mask).
微影裝置可為具有兩個(雙平台)或兩個以上基板台(及/或兩個或兩個以上光罩台)的類型。在該等"多平台"機器中，可並行地使用額外台，或可在一或多個台上進行預備步驟，同時將一或多個其他台用於曝光。The lithography device can be of the type having two (dual platforms) or more than two substrate stages (and/or two or more reticle stages). In such "multi-platform" machines, additional stations may be used in parallel, or preliminary steps may be performed on one or more stations while one or more other stations are used for exposure.
微影裝置亦可為如下類型：其中基板之至少一部分可由具有相對較高折射率之液體(例如，水)覆蓋，以便填充投影系統與基板之間的空間。亦可將浸沒液體施加至微影裝置中之其他空間，例如，光罩與投影系統之間。浸沒技術在此項技術中被熟知用於增加投影系統之數值孔徑。如本文所使用之術語"浸沒"不意謂諸如基板之結構必須浸漬於液體中，而是僅意謂液體在曝光期間位於投影系統與基板之間。The lithography apparatus can also be of the type wherein at least a portion of the substrate can be covered by a liquid (eg, water) having a relatively high refractive index to fill the space between the projection system and the substrate. The immersion liquid can also be applied to other spaces in the lithography apparatus, such as between the reticle and the projection system. Immersion techniques are well known in the art for increasing the numerical aperture of a projection system. The term "immersion" as used herein does not mean that a structure such as a substrate must be immersed in a liquid, but rather only means that the liquid is located between the projection system and the substrate during exposure.
參看圖1a，照明器IL自輻射源SO接收輻射光束。舉例而言，當輻射源為準分子雷射器時，輻射源與微影裝置可為單獨實體。在該等情況下，不認為輻射源形成微影裝置之一部分，且輻射光束借助於包含(例如)適當引導鏡面及/或光束放大器之光束傳送系統BD而自輻射源SO傳遞至照明器IL。在其他情況下，例如，當輻射源為汞燈時，輻射源可為微影裝置之整體部分。輻射源SO及照明器IL連同光束傳送系統BD(在需要時)可被稱作輻射系統。Referring to Figure 1a, illuminator IL receives a radiation beam from radiation source SO. For example, when the radiation source is an excimer laser, the radiation source and the lithography device can be separate entities. In such cases, the radiation source is not considered to form part of the lithography apparatus, and the radiation beam is transmitted from the radiation source SO to the illuminator IL by means of a beam delivery system BD comprising, for example, a suitable guiding mirror and/or beam amplifier. In other cases, for example, when the source of radiation is a mercury lamp, the source of radiation may be an integral part of the lithography apparatus. The radiation source SO and illuminator IL together with the beam delivery system BD (when needed) may be referred to as a radiation system.
照明器IL可包含用於調整輻射光束之角強度分布的調整器AD。通常，可調整照明器之光瞳平面中之強度分布的至少外部徑向範圍及/或內部徑向範圍(通常分別被稱作σ外部及σ內部)。此外，照明器IL可包含各種其他組件，諸如，積光器IN及聚光器CO。照明器可用以調節輻射光束，以在其橫截面中具有所要均一性及強度分布。The illuminator IL may comprise an adjuster AD for adjusting the angular intensity distribution of the radiation beam. In general, at least the outer radial extent and/or the inner radial extent (commonly referred to as σ outer and σ inner, respectively) of the intensity distribution in the pupil plane of the illuminator can be adjusted. Further, the illuminator IL may include various other components such as the concentrator IN and the concentrator CO. The illuminator can be used to adjust the radiation beam to have a desired uniformity and intensity distribution in its cross section.
輻射光束B入射於固持於支撐結構(例如，光罩台MT)上之圖案化器件(例如，光罩MA)上，且由圖案化器件圖案化。在橫穿光罩MA後，輻射光束B穿過投影系統PL，投影系統PL將光束聚焦至基板W之目標部分C上。借助於第二定位器PW及位置感測器IF(例如，干涉測量器件、線性編碼器、2-D編碼器或電容性感測器)，基板台WT可精確地移動，例如，以便在輻射光束B之路徑中定位不同目標部分C。類似地，第一定位器PM及另一位置感測器(其未在圖1a中被明確地描繪)可用以(例如)在自光罩庫之機械擷取之後或在掃描期間相對於輻射光束B之路徑來精確地定位光罩MA。一般而言，可借助於形成第一定位器PM之一部分的長衝程模組(粗略定位)及短衝程模組(精細定位)來實現光罩台MT之移動。類似地，可使用形成第二定位器PW之一部分的長衝程模組及短衝程模組來實現基板台WT之移動。在步進器(與掃描器相對)之情況下，光罩台MT可僅連接至短衝程致動器，或可為固定的。可使用光罩對準標記M1、M2及基板對準標記P1、P2來對準光罩MA及基板W。儘管如所說明之基板對準標記佔用專用目標部分，但其可位於目標部分之間的空間中(此等被稱為切割道對準標記)。類似地，在一個以上晶粒提供於光罩MA上之情形中，光罩對準標記可位於該等晶粒之間。The radiation beam B is incident on a patterned device (e.g., reticle MA) held on a support structure (e.g., reticle stage MT) and patterned by the patterned device. After traversing the reticle MA, the radiation beam B passes through the projection system PL, and the projection system PL focuses the beam onto the target portion C of the substrate W. By means of the second positioner PW and the position sensor IF (for example, an interferometric device, a linear encoder, a 2-D encoder or a capacitive sensor), the substrate table WT can be accurately moved, for example, in order to radiate a beam of light Position different target parts C in the path of B. Similarly, the first locator PM and another position sensor (which is not explicitly depicted in Figure 1a) can be used, for example, after mechanical scooping from the reticle library or during scanning relative to the radiation beam The path of B to accurately position the mask MA. In general, the movement of the reticle stage MT can be achieved by means of a long stroke module (rough positioning) and a short stroke module (fine positioning) forming part of the first positioner PM. Similarly, the movement of the substrate table WT can be accomplished using a long stroke module and a short stroke module that form part of the second positioner PW. In the case of a stepper (as opposed to a scanner), the reticle stage MT can be connected only to a short-stroke actuator or can be fixed. The mask MA and the substrate W can be aligned using the mask alignment marks M1, M2 and the substrate alignment marks P1, P2. Although the substrate alignment marks occupy a dedicated target portion as illustrated, they may be located in the space between the target portions (this is referred to as a scribe line alignment mark). Similarly, where more than one die is provided on the reticle MA, a reticle alignment mark can be located between the dies.
所描繪裝置可用於以下模式中之至少一者中：The depicted device can be used in at least one of the following modes:
1.在步進模式中，在將被賦予至輻射光束之整個圖案一次性投影至目標部分C上時，使光罩台MT及基板台WT保持基本上靜止(亦即，單重靜態曝光)。接著，使基板台WT在X及/或Y方向上移位，使得可曝光不同目標部分C。在步進模式中，曝光場之最大尺寸限制單重靜態曝光中所成像之目標部分C的尺寸。1. In the step mode, when the entire pattern to be applied to the radiation beam is projected onto the target portion C at a time, the mask table MT and the substrate table WT are kept substantially stationary (ie, single static exposure). . Next, the substrate stage WT is displaced in the X and/or Y direction so that different target portions C can be exposed. In the step mode, the maximum size of the exposure field limits the size of the target portion C imaged in the single static exposure.
2.在掃描模式中，在將被賦予至輻射光束之圖案投影至目標部分C上時，同步地掃描光罩台MT及基板台WT(亦即，單重動態曝光)。可藉由投影系統PL之放大率(縮小率)及影像反轉特性來判定基板台WT相對於光罩台MT之速度及方向。在掃描模式中，曝光場之最大尺寸限制單重動態曝光中之目標部分的寬度(在非掃描方向上)，而掃描運動之長度判定目標部分之高度(在掃描方向上)。2. In the scan mode, when the pattern to be given to the radiation beam is projected onto the target portion C, the mask table MT and the substrate stage WT are scanned synchronously (i.e., single dynamic exposure). The speed and direction of the substrate stage WT with respect to the mask table MT can be determined by the magnification (reduction ratio) and the image inversion characteristic of the projection system PL. In the scan mode, the maximum size of the exposure field limits the width of the target portion in the single-shot dynamic exposure (in the non-scanning direction), and the length of the scanning motion determines the height of the target portion (in the scanning direction).
3.在另一模式中，在將被賦予至輻射光束之圖案投影至目標部分C上時，使光罩台MT保持基本上靜止，從而固持可程式化圖案化器件，且移動或掃描基板台WT。在此模式中，通常使用脈衝式輻射源，且在基板台WT之每一移動之後或在掃描期間的順次輻射脈衝之間根據需要而更新可程式化圖案化器件。此操作模式可易於應用於利用可程式化圖案化器件(諸如，如以上所提及之類型的可程式化鏡面陣列)之無光罩微影術。3. In another mode, when the pattern to be imparted to the radiation beam is projected onto the target portion C, the reticle stage MT is held substantially stationary, thereby holding the programmable patterning device and moving or scanning the substrate table WT. In this mode, a pulsed radiation source is typically used and the programmable patterning device is updated as needed between each movement of the substrate table WT or between successive pulses of radiation during the scan. This mode of operation can be readily applied to matte lithography utilizing a programmable patterning device such as a programmable mirror array of the type mentioned above.
亦可使用對以上所描述之使用模式之組合及/或變化或完全不同的使用模式。Combinations and/or variations or completely different modes of use of the modes of use described above may also be used.
如圖1b所示，微影裝置LA形成微影單元LC(有時亦被稱作微影單元或叢集)之一部分，其亦包括用以對基板執行預曝光及後曝光過程之裝置。通常，此等裝置包括用以沈積抗蝕劑層之旋塗器SC、用以顯影經曝光抗蝕劑之顯影器DE、冷卻板CH，及烘焙板BK。基板處置器或機器人RO自輸入/輸出埠I/O1、I/O2拾取基板、在不同處理裝置之間移動基板，且接著將基板傳送至微影裝置之裝載盤LB。通常被共同地稱作軌道之此等器件係在軌道控制單元TCU的控制下，軌道控制單元TCU自身受監督控制系統SCS控制，監督控制系統SCS亦經由微影控制單元LACU而控制微影裝置。因此，不同裝置可經操作以最大化產出率及處理效率。As shown in FIG. 1b, the lithography apparatus LA forms part of a lithography unit LC (sometimes referred to as a lithography unit or cluster), which also includes means for performing pre-exposure and post-exposure processes on the substrate. Typically, such devices include a spin coater SC for depositing a resist layer, a developer DE for developing the exposed resist, a cooling plate CH, and a baking plate BK. The substrate handler or robot RO picks up the substrate from the input/output ports I/O1, I/O2, moves the substrate between different processing devices, and then transfers the substrate to the loading tray LB of the lithography device. These devices, commonly referred to collectively as tracks, are under the control of the track control unit TCU, which is itself controlled by the supervisory control system SCS, which also controls the lithography device via the lithography control unit LACU. Thus, different devices can be operated to maximize yield and processing efficiency.
為了正確且一致地曝光由微影裝置所曝光之基板，需要檢測經曝光基板以測量特性，諸如，後續層之間的疊對誤差、線厚度、臨界尺寸(CD)，等等。若偵測到誤差，則可對後續基板之曝光進行調整，尤其在度量衡可足夠迅速且快速地進行以使得同一分批之其他基板仍待曝光的情況下。又，已經曝光之基板可經剝離及重做-改良良率-廢除，藉此避免對已知為有缺陷之基板執行曝光。在基板之僅某些目標部分為有缺陷之情況下，可僅對為良好之彼等目標部分執行另外曝光。In order to properly and consistently expose the substrate exposed by the lithography apparatus, it is necessary to detect the exposed substrate to measure characteristics such as stacking errors between subsequent layers, line thickness, critical dimension (CD), and the like. If an error is detected, the exposure of the subsequent substrate can be adjusted, especially if the metrology can be performed quickly enough quickly and quickly so that the other substrates of the same batch are still to be exposed. Also, the exposed substrate can be stripped and reworked - improved yield - abolished, thereby avoiding exposure to a substrate that is known to be defective. In the case where only certain target portions of the substrate are defective, additional exposure may be performed only for the target portions that are good.
使用度量衡裝置以判定基板之特性，且特別為判定不同基板或同一基板之不同層的特性如何在層與層之間變化。度量衡裝置可整合至微影裝置LA或微影單元LC中或可為單獨器件。為了實現最快速之測量，需要使度量衡裝置在曝光之後立即測量經曝光抗蝕劑層中之特性。然而，抗蝕劑中之潛影具有極低對比度-在抗蝕劑之已曝光至輻射之部分與抗蝕劑之尚未曝光至輻射之部分之間僅存在極小的折射率差-且並非所有度量衡裝置均具有對進行潛影之有用測量的充分敏感性。因此，可在後曝光烘焙步驟(PEB)之後採取測量，後曝光烘焙步驟通常為對經曝光基板所進行之第一步驟且其增加抗蝕劑之經曝光部分與未經曝光部分之間的對比度。在此階段，抗蝕劑中之影像可被稱作半潛伏的。亦有可能進行經顯影抗蝕劑影像之測量-此時，抗蝕劑之經曝光部分或未經曝光部分已被移除-或在圖案轉印步驟(諸如，蝕刻)之後進行經顯影抗蝕劑影像之測量。後者可能性限制重做有缺陷基板之可能性，但仍可提供有用資訊。A metrology device is used to determine the characteristics of the substrate, and in particular to determine how the properties of different substrates or different layers of the same substrate vary between layers. The metrology device can be integrated into the lithography device LA or lithography unit LC or can be a separate device. In order to achieve the fastest measurement, it is necessary to have the metrology device measure the characteristics in the exposed resist layer immediately after exposure. However, the latent image in the resist has a very low contrast - there is only a very small difference in refractive index between the portion of the resist that has been exposed to the radiation and the portion of the resist that has not been exposed to the radiation - and not all weights and measures The devices all have sufficient sensitivity to useful measurements of the latent image. Thus, measurements can be taken after the post-exposure bake step (PEB), which is typically the first step performed on the exposed substrate and which increases the contrast between the exposed and unexposed portions of the resist . At this stage, the image in the resist can be referred to as semi-latent. It is also possible to perform a measurement of the developed resist image - at this time, the exposed or unexposed portion of the resist has been removed - or developed resist after the pattern transfer step (such as etching) Measurement of the agent image. The latter possibility limits the possibility of redoing defective substrates, but still provides useful information.
圖2描繪用作度量衡裝置之散射計SM1。散射計SM1包含寬頻帶(白光)輻射投影儀2，其將輻射投影至基板W上。經反射輻射傳遞至分光計偵測器4，其測量鏡面經反射輻射之光譜10(作為波長之函數的強度)。自此資料，可藉由處理單元PU來重新建構引起經偵測光譜之結構或資料檔(profile)，例如，藉由嚴密耦合波分析及非線性回歸或藉由與如圖2之底部處所示之模擬光譜庫比較。一般而言，對於重新建構，結構之通用形式為已知的，且根據對製造結構所採用之過程的認識來假定某些參數，從而僅留下結構之少許參數以自散射測量資料加以判定。該散射計可經組態為正入射散射計或斜入射散射計。Figure 2 depicts a scatterometer SM1 used as a metrology device. The scatterometer SM1 comprises a broadband (white light) radiation projector 2 that projects radiation onto the substrate W. The reflected radiation is transmitted to a spectrometer detector 4 which measures the spectrum 10 of the specular reflected radiation (intensity as a function of wavelength). From this data, the structure or profile of the detected spectrum can be reconstructed by the processing unit PU, for example, by tightly coupled wave analysis and nonlinear regression or by the bottom of Figure 2 The analog spectrum library comparison shown. In general, for reconstitution, the general form of the structure is known, and certain parameters are assumed based on knowledge of the process employed to fabricate the structure, leaving only a few parameters of the structure to be determined from the self-scattering measurements. The scatterometer can be configured as a normal incidence scatterometer or an oblique incidence scatterometer.
圖3描繪用作度量衡裝置之散射計SM2的一實施例。散射計SM2具備輻射源2、透鏡系統12、干涉濾光器13、部分反射表面16及顯微鏡接物鏡15。接物鏡15具有高數值孔徑(NA)，諸如，至少0.9或至少0.95。浸沒散射計可甚至具有數值孔徑超過1之透鏡。此外，散射計SM2具備偵測器D。在操作中，由輻射源2所發射之輻射使用透鏡系統12經由干涉濾光器13及偏振器17而聚焦、由部分反射表面16反射且經由顯微鏡接物鏡15而聚焦至基板W上。經反射輻射接著透過部分反射表面16而進入偵測器D中，以便偵測散射光譜。偵測器D可位於處於透鏡系統15之焦距F的背部投影式光瞳平面11中，然而，光瞳平面可代替地藉由輔助光學器件(未圖示)而再成像至偵測器D上。光瞳平面為輻射之徑向位置界定入射角且角位界定輻射之方位角的平面。偵測器D可為二維偵測器，使得可測量基板目標30之二維角散射光譜。偵測器D可為(例如)CCD或CMOS感測器陣列，且可使用為(例如)每訊框40毫秒之積分時間。Figure 3 depicts an embodiment of a scatterometer SM2 used as a metrology device. The scatterometer SM2 includes a radiation source 2, a lens system 12, an interference filter 13, a partially reflective surface 16, and a microscope objective lens 15. The objective lens 15 has a high numerical aperture (NA), such as at least 0.9 or at least 0.95. An immersion scatterometer can even have a lens with a numerical aperture greater than one. Further, the scatterometer SM2 is provided with a detector D. In operation, the radiation emitted by the radiation source 2 is focused by the lens system 12 via the interference filter 13 and the polarizer 17, reflected by the partially reflective surface 16 and focused onto the substrate W via the microscope objective lens 15. The reflected radiation then passes through the partially reflective surface 16 into the detector D to detect the scattered spectrum. The detector D can be located in the back projection aperture plane 11 at the focal length F of the lens system 15, however, the pupil plane can instead be re-imaged onto the detector D by means of auxiliary optics (not shown). . The pupil plane defines the angle of incidence for the radial position of the radiation and the plane defining the azimuth of the radiation. The detector D can be a two-dimensional detector such that the two-dimensional angular scatter spectrum of the substrate target 30 can be measured. The detector D can be, for example, a CCD or CMOS sensor array and can be used, for example, for an integration time of 40 milliseconds per frame.
舉例而言，可使用參考光束以測量入射輻射之強度。為了進行此過程，當輻射光束入射於光束分光器16上時，輻射光束之一部分透過光束分光器而作為朝向參考鏡面14之參考光束。參考光束接著投影至同一偵測器D之不同部分上。For example, a reference beam can be used to measure the intensity of incident radiation. To perform this process, when the radiation beam is incident on the beam splitter 16, one of the radiation beams is partially transmitted through the beam splitter as a reference beam toward the reference mirror 14. The reference beam is then projected onto different portions of the same detector D.
干涉濾光器13之集合可用以選擇在為(例如)405奈米至790奈米或甚至更低(諸如，200奈米至300奈米)之範圍內的所關注波長。干涉濾光器可為可調諧的，而非包含不同濾光器之集合。可代替干涉濾光器而使用光柵。The set of interference filters 13 can be used to select wavelengths of interest in the range of, for example, 405 nm to 790 nm or even lower (such as 200 nm to 300 nm). The interference filter can be tunable rather than containing a collection of different filters. A grating can be used instead of the interference filter.
偵測器D可測量經散射光在單一波長(或窄波長範圍)下之強度、單獨地在多個波長下之強度，或在一波長範圍內順序地或並行地所積分之強度。偵測器可單獨地測量橫向磁偏振光及橫向電偏振光之強度，及/或橫向磁偏振光與橫向電偏振光之間的相位差。The detector D can measure the intensity of the scattered light at a single wavelength (or a narrow wavelength range), the intensity at a plurality of wavelengths alone, or the intensity integrated sequentially or in parallel over a range of wavelengths. The detector can separately measure the intensity of the transversely polarized light and the transversely polarized light, and/or the phase difference between the transversely polarized light and the laterally polarized light.
可使用給出較大光展量(etendue)之寬頻帶光源(亦即，具有寬光頻率或波長範圍且因此具有寬顏色範圍之光源)，藉此允許多個波長之混合。寬頻帶中之複數個波長可各自具有為Δλ之頻寬及為至少2Δλ(亦即，為頻寬之兩倍)之間隔。若干輻射"源"可為經擴展輻射源之已使用光纖束而被分裂的不同部分。以此方式，可在多個波長下並行地測量角度解析散射光譜。可測量3-D光譜(波長及兩個不同角度)，其含有比2-D光譜多之資訊。此可允許測量更多資訊，其增加度量衡過程穩固性。此更詳細地描述於歐洲專利申請公開案第1,628,164A號中。A broadband source that gives a large etendue (i.e., a source having a wide optical frequency or range of wavelengths and thus a wide range of colors) can be used, thereby allowing mixing of multiple wavelengths. The plurality of wavelengths in the wideband may each have a bandwidth of Δλ and an interval of at least 2 Δλ (i.e., twice the bandwidth). Several "sources" of radiation may be different portions of the extended source of radiation that have been split using the bundle of fibers. In this way, the angular resolution scattering spectra can be measured in parallel at multiple wavelengths. The 3-D spectrum (wavelength and two different angles) can be measured, which contains more information than the 2-D spectrum. This allows for more information to be measured, which increases the robustness of the weights and measures process. This is described in more detail in European Patent Application Publication No. 1,628,164 A.
基板W上之目標30可為光柵，其經列印，使得在顯影之後，條狀物(bar)係由固體抗蝕劑線形成。條狀物可或者經蝕刻至基板中。此圖案對微影投影裝置(特別為投影系統PL)中之色像差敏感，且照明對稱性及該等像差之存在可使其自身表現為經列印光柵之變化。因此，可將經列印光柵之散射測量資料用以重新建構光柵。根據對列印步驟及/或其他散射測量過程之認識，可將光柵之參數(諸如，線寬及形狀)輸入至由處理單元PU所執行之重新建構過程。The target 30 on the substrate W can be a grating that is printed such that after development, the bars are formed from solid resist lines. The strips can either be etched into the substrate. This pattern is sensitive to chromatic aberrations in lithographic projection devices, particularly projection system PL, and the illumination symmetry and the presence of such aberrations can manifest themselves as changes in the printed raster. Therefore, the scatter data of the printed grating can be used to reconstruct the grating. Depending on the printing step and/or other scatterometry processes, the parameters of the grating, such as line width and shape, can be input to the reconstruction process performed by the processing unit PU.
圖4描繪具有用作度量衡裝置之影像場選擇器件(選擇器)29之散射計40的實施例。散射計40以此次序包含光源2、透鏡系統25、26、照明界定孔徑27、透鏡12、干涉濾光器13及偏振器17、光束分光元件16及接物鏡15。接物鏡15可為(例如)具有為0.9之NA的高NA透鏡。光源可為UHP燈、白熾燈或"白光"雷射器。UHP燈應適合於發射具有(例如)在180奈米至800奈米之範圍內之波長的輻射。散射計40可進一步包含另一光束分光器18及影像感測器22(偵測器)。影像場界定器件29包含透鏡19、21及具備孔徑28之葉片20。透鏡19、21在定位有孔徑28之平面中形成基板之影像。在一實施例中，可省略透鏡19、21。4 depicts an embodiment of a scatterometer 40 having an image field selection device (selector) 29 for use as a metrology device. The scatterometer 40 includes the light source 2, the lens systems 25, 26, the illumination defining aperture 27, the lens 12, the interference filter 13 and the polarizer 17, the beam splitting element 16 and the objective lens 15 in this order. The objective lens 15 can be, for example, a high NA lens having an NA of 0.9. The light source can be a UHP lamp, an incandescent lamp or a "white light" laser. The UHP lamp should be suitable for emitting radiation having a wavelength, for example, in the range of from 180 nanometers to 800 nanometers. The scatterometer 40 can further include another beam splitter 18 and an image sensor 22 (detector). The image field defining device 29 includes lenses 19, 21 and blades 20 having apertures 28. The lenses 19, 21 form an image of the substrate in a plane in which the aperture 28 is positioned. In an embodiment, the lenses 19, 21 may be omitted.
在操作中，光源2經由透鏡元件25、照明界定孔徑27、透鏡元件26、12、干涉濾光器13、偏振器17、光束分光元件16及接物鏡15而將輻射光束發射至基板W上之目標部分30。照明界定孔徑27對於第1階疊對測量可為環形孔徑，或分別對於第一階疊對及臨界尺寸(CD)重新建構可為圓形孔徑。視目標30之尺寸而定，可選擇環形環之不同尺寸或圓形孔徑之不同半徑。基板W上之經照明目標30經由接物鏡15、光束分光元件16、18、透鏡19、孔徑28及透鏡21而將零階及更高階之碰撞光束散射至影像感測器22。影像感測器22可為CCD或CMOS影像感測器。通常，碰撞光束之光點幾何形狀界定經照明區域之形狀，其促進接物鏡15之光瞳平面的光瞳形狀。經照明區域可具有(例如)半徑為25μm之圓形尺寸。定位於接物鏡15與影像感測器22之間的透鏡21、19將接物鏡15之光瞳平面成像於影像感測器22上。透鏡19在透鏡19、21之間形成基板之中間影像。中間平面為與晶圓表面相關聯之共軛平面。在此實施例中，孔徑28定位於中間影像中。孔徑28選擇影像場之對應於晶圓W之預定目標30的部分，自此必須獲得CD或疊對測量。此部分可接著僅促進光瞳平面資訊。在不應用透鏡19、21之實施例中，孔徑28應定位於接物鏡15之影像平面中。In operation, the light source 2 emits a radiation beam onto the substrate W via the lens element 25, the illumination defining aperture 27, the lens elements 26, 12, the interference filter 13, the polarizer 17, the beam splitting element 16, and the objective lens 15. Target section 30. The illumination defining aperture 27 can be an annular aperture for the first order overlay pair or a circular aperture for the first order stack and critical dimension (CD) reconstruction, respectively. Depending on the size of the target 30, different radii of different sizes or circular apertures of the annular ring may be selected. The illumination target 30 on the substrate W scatters the zero-order and higher-order collision beams to the image sensor 22 via the objective lens 15, the beam splitting elements 16, 18, the lens 19, the aperture 28, and the lens 21. Image sensor 22 can be a CCD or CMOS image sensor. Typically, the spot geometry of the colliding beam defines the shape of the illuminated region that promotes the pupil shape of the pupil plane of the objective lens 15. The illuminated area can have, for example, a circular size with a radius of 25 [mu]m. The lenses 21, 19 positioned between the objective lens 15 and the image sensor 22 image the pupil plane of the objective lens 15 onto the image sensor 22. The lens 19 forms an intermediate image of the substrate between the lenses 19,21. The median plane is the conjugate plane associated with the wafer surface. In this embodiment, the aperture 28 is positioned in the intermediate image. The aperture 28 selects the portion of the image field that corresponds to the predetermined target 30 of the wafer W, from which CD or overlay measurements must be obtained. This section can then only promote the pupil plane information. In embodiments where the lenses 19, 21 are not applied, the aperture 28 should be positioned in the image plane of the objective lens 15.
在此實施例中，類似於關於圖3所描述之實施例，存在用於校準影像感測器22之參考光束。參考光束經由第二光束分光元件16及鏡面14而自照明光束分裂開，且經由光束分光元件16及18而引導至影像感測器22。In this embodiment, similar to the embodiment described with respect to FIG. 3, there is a reference beam for calibrating image sensor 22. The reference beam splits from the illumination beam via the second beam splitting element 16 and the mirror 14 and is directed to the image sensor 22 via the beam splitting elements 16 and 18.
此外，光束分光元件18自來自基板W之經反射光束分裂開對準光束，且經由透鏡23而將對準光束轉移至影像對準感測器24。In addition, the beam splitting element 18 splits the aligned beam from the reflected beam from the substrate W and transfers the aligned beam to the image alignment sensor 24 via the lens 23.
藉由選擇影像場界定器件29之孔徑的尺寸及形狀，可以靈活方式來改變對光瞳平面資訊之促進。此靈活性可允許在測量速度、精確度及再現性等等方面之最佳結果。By selecting the size and shape of the aperture of the image field defining device 29, the promotion of pupil plane information can be changed in a flexible manner. This flexibility allows for the best results in terms of measurement speed, accuracy and reproducibility.
晶圓平面與中間影像場之間的放大率為固定的且為(例如)30倍。在一實施例中，孔徑28之直徑可經選擇為150μm。藉由為30x之放大率，晶圓表面上之目標的直徑等於5μm。實務上，基板W上之鄰近晶粒之間的切割道中之光柵目標30具有(例如)為40x40μm之尺寸，且基板上之照明光點的尺寸具有(例如)為25μm之直徑。在該實例中，目標據說係由照明光束進行底部填充。當以在基板上具有為12μm之直徑之照明光點來操作此實施例以用於測量基板W上之20x20μm目標時，照明光點可能難以與基板W處之目標30對準。The magnification between the wafer plane and the intermediate image field is fixed and is, for example, 30 times. In an embodiment, the diameter of the aperture 28 can be selected to be 150 [mu]m. By a magnification of 30x, the diameter of the target on the wafer surface is equal to 5 μm. In practice, the grating target 30 in the scribe line between adjacent grains on the substrate W has, for example, a size of 40 x 40 μm, and the size of the illumination spot on the substrate has, for example, a diameter of 25 μm. In this example, the target is said to be underfilled by the illumination beam. When this embodiment is operated with an illumination spot having a diameter of 12 [mu]m on the substrate for measuring a 20x20 [mu]m target on the substrate W, the illumination spot may be difficult to align with the target 30 at the substrate W.
在習知散射計中，最小目標區域可受以照明光束所獲得之光點尺寸及來自對準、振動及光學旁瓣之促進的限制。可經由具備360μm直徑之圓形孔徑28的影像場選擇器件29而選擇基板W處之20x20μm目標區域。具備此尺寸之孔徑的影像場選擇器件29與基板W處12μm直徑之照明光束光點的對準相比可更容易地與基板對準。藉由選擇影像場選擇器件29之孔徑28的不同直徑及形狀，可實現基板W上之目標的較大尺寸範圍及基板之切割道區域中之光柵目標以及基板W上之單一晶粒之區域內部之目標處的測量。在此配置中，目標之大部分表面可用於測量，其可由於測量中所使用之更高強度而導致更高產出率。In conventional scatterometers, the minimum target area can be limited by the size of the spot obtained with the illumination beam and by the promotion of alignment, vibration, and optical side lobes. The 20x20 μm target area at the substrate W can be selected via the image field selection device 29 having a circular aperture 28 of 360 μm diameter. The image field selection device 29 having an aperture of this size can be more easily aligned with the substrate than the alignment of the 12 [mu]m diameter illumination beam spot at the substrate W. By selecting different diameters and shapes of the apertures 28 of the image field selection device 29, a larger size range of the target on the substrate W and a grating target in the scribe line region of the substrate and a single crystal region on the substrate W can be realized. Measurement at the target. In this configuration, most of the surface of the target can be used for measurements, which can result in higher yields due to the higher intensity used in the measurements.
圖5描繪可移動板之一實施例，例如，用於如本文所描述之散射計之一實施例中的可旋轉輪50。可旋轉輪50可具備分別為不同尺寸之三個圓形孔徑51、52、53，及正方形孔徑54。可旋轉輪可藉由步進器馬達而旋轉。Figure 5 depicts an embodiment of a movable plate, such as a rotatable wheel 50 for use in one embodiment of a scatterometer as described herein. The rotatable wheel 50 can be provided with three circular apertures 51, 52, 53 of different sizes, respectively, and a square aperture 54. The rotatable wheel can be rotated by a stepper motor.
圖6描繪用於如本文所描述之散射計之一實施例中之虹膜光闌60的實施例。虹膜光闌60包含可移動葉片61、62。個別葉片61、62之位置判定光闌60之中心處或附近之孔徑63的尺寸。個別葉片之位置可藉由步進器馬達而調整。虹膜光闌60可經調適成較大直徑範圍，且可以緊密方式而整合於散射計中。FIG. 6 depicts an embodiment of an iris diaphragm 60 for use in one embodiment of a scatterometer as described herein. The iris diaphragm 60 includes movable vanes 61,62. The position of the individual blades 61, 62 determines the size of the aperture 63 at or near the center of the aperture 60. The position of individual blades can be adjusted by a stepper motor. The iris diaphragm 60 can be adapted to a larger diameter range and integrated into the scatterometer in a compact manner.
圖7描繪具有影像場選擇器件75之散射計70的一實施例。散射計70可以此一般次序包含光源2、透鏡系統25、26、照明界定孔徑27、透鏡12、干涉濾光器13、偏振器17、光束分光元件16、接物鏡15、光束分光元件18、影像場選擇器件75及影像感測器22。光源可為適合於發射具有在180奈米至800奈米之間的範圍內之波長之輻射的UHP燈。在一實施例中，可應用白熾燈或"白光"雷射器。接物鏡可為高NA透鏡(例如，為0.90或0.95之NA)。FIG. 7 depicts an embodiment of a scatterometer 70 having an image field selection device 75. The scatterometer 70 may include the light source 2, the lens system 25, 26, the illumination defining aperture 27, the lens 12, the interference filter 13, the polarizer 17, the beam splitting element 16, the objective lens 15, the beam splitting element 18, and the image in this general order. Field selection device 75 and image sensor 22. The light source can be a UHP lamp suitable for emitting radiation having a wavelength in the range between 180 nanometers and 800 nanometers. In an embodiment, an incandescent or "white light" laser can be applied. The objective lens can be a high NA lens (eg, a NA of 0.90 or 0.95).
影像場選擇器件75可包含透鏡19、全內反射(TIR)稜鏡41、可調整鏡面陣列42及透鏡21。影像場選擇器件亦可包含經組態以調整可調整鏡面陣列42之控制器43。可調整鏡面陣列可為數位鏡面器件，例如，如可自Texas Instruments獲得之XGA DLP晶片。又，可代替可調整鏡面陣列42而使用其他種類之空間光調變器(SLM)或微機電系統(MEMS)。在一實施例中，可省略透鏡19、21；數位鏡面器件應接著定位於接物鏡之影像平面處。The image field selection device 75 can include a lens 19, a total internal reflection (TIR) 稜鏡 41, an adjustable mirror array 42 and a lens 21. The image field selection device can also include a controller 43 that is configured to adjust the adjustable mirror array 42. The adjustable mirror array can be a digital mirror device such as, for example, an XGA DLP wafer available from Texas Instruments. Also, other types of spatial light modulators (SLM) or microelectromechanical systems (MEMS) can be used instead of the adjustable mirror array 42. In an embodiment, the lenses 19, 21 may be omitted; the digital mirror device should then be positioned at the image plane of the objective.
在操作中，光源2經由透鏡元件25、照明界定孔徑27、透鏡元件26、12、干涉濾光器13、偏振器17、光束分光元件16及接物鏡15而將輻射光束發射至基板W上之目標部分30。照明界定孔徑27對於第1階疊對測量可為環形孔徑，且對於基於臨界(CD)重新建構之測量可為圓形孔徑。視基板W上之目標30之尺寸而定，可選擇環形環之不同尺寸或圓形孔徑之不同半徑。基板W上之經照明目標30經由接物鏡15、光束分光元件16、18、透鏡20、影像場選擇器件75及透鏡21而將零階及更高階之碰撞光束散射至影像感測器22。影像感測器22可為(例如)CCD或CMOS影像感測器。In operation, the light source 2 emits a radiation beam onto the substrate W via the lens element 25, the illumination defining aperture 27, the lens elements 26, 12, the interference filter 13, the polarizer 17, the beam splitting element 16, and the objective lens 15. Target section 30. The illumination defining aperture 27 can be an annular aperture for a first order overlay and a circular aperture for a critical (CD) based reconstruction. Depending on the size of the target 30 on the substrate W, different radii of different sizes or circular apertures of the annular ring may be selected. The illumination target 30 on the substrate W scatters the zero-order and higher-order collision beams to the image sensor 22 via the objective lens 15, the beam splitting elements 16, 18, the lens 20, the image field selecting device 75, and the lens 21. Image sensor 22 can be, for example, a CCD or CMOS image sensor.
碰撞光束之光點幾何形狀可界定經照明區域之形狀，其促進接物鏡15之光瞳平面的光瞳形狀。經照明區域可具有(例如)直徑為25μm之圓形尺寸。透鏡19、21將此光瞳平面成像於影像感測器22上。透鏡19在透鏡21、19之間形成影像場平面。The spot geometry of the colliding beam can define the shape of the illuminated region that promotes the pupil shape of the pupil plane of the objective lens 15. The illuminated area can have, for example, a circular size with a diameter of 25 μm. The lenses 19, 21 image this pupil plane onto the image sensor 22. The lens 19 forms an image field plane between the lenses 21, 19.
在第一步驟中，控制器43可經由使用者介面而獲得影像場平面之對應於基板W處之選定目標30之部分的尺寸及位置。在另一步驟中，控制器43可調整數位鏡面器件42之第一數位鏡面群組的位置，使得對應於中間影像場之選定部分之光束的角度小於TIR稜鏡41內部之介面的布汝士特(Brewster)角，且光束之經反射部分經由TIR稜鏡41及透鏡21而引導至影像感測器22。控制器43可調整數位鏡面器件42之第二數位鏡面群組，使得對應於目標區域之非選定部分之光束經引導至光束捕集器(未圖示)。In a first step, the controller 43 can obtain the size and position of the portion of the image field plane corresponding to the selected target 30 at the substrate W via the user interface. In another step, the controller 43 adjusts the position of the first digital mirror group of the integer position mirror device 42 such that the angle of the beam corresponding to the selected portion of the intermediate image field is smaller than the internal interface of the TIR稜鏡41 interface. The Brewster angle, and the reflected portion of the beam is directed to the image sensor 22 via the TIR 41 and the lens 21. The controller 43 adjusts the second digital mirror group of the integer position mirror device 42 such that a beam corresponding to a non-selected portion of the target region is directed to a beam trap (not shown).
圖8描繪具有影像場選擇器件85之散射計80的一實施例。散射計80以此一般次序包含光源2、透鏡系統25、26、照明界定孔徑27、透鏡12、干涉濾光器13、偏振器17、光束分光元件16、接物鏡15、光束分光元件18、影像場選擇器件85及影像感測器22。光源2可為適合於發射具有在300奈米至800奈米之間的範圍內之波長之輻射的UHP燈。在一實施例中，可應用白熾燈或白光雷射器。接物鏡可為高NA接物鏡(例如，具有為0.90或0.95之NA)。影像場選擇器件85可包含透鏡19、凹入鏡面71、可調整鏡面陣列72及透鏡21。影像場選擇器件85亦可包含經組態以調整可調整鏡面陣列72之控制器73。可調整鏡面陣列可為數位鏡面器件，例如，如可自Texas Instruments獲得之XGA DLP晶片。又，可代替可調整鏡面陣列42而使用其他種類之空間光調變器(SLM)或微機電系統(MEMS)。在一實施例中，可省略透鏡19、21；數位鏡面器件應接著定位於接物鏡之影像平面處。FIG. 8 depicts an embodiment of a scatterometer 80 having an image field selection device 85. The scatterometer 80 includes the light source 2, the lens system 25, 26, the illumination defining aperture 27, the lens 12, the interference filter 13, the polarizer 17, the beam splitting element 16, the objective lens 15, the beam splitting element 18, and the image in this general order. Field selection device 85 and image sensor 22. Light source 2 can be a UHP lamp suitable for emitting radiation having a wavelength in the range between 300 nanometers and 800 nanometers. In an embodiment, an incandescent or white light laser can be applied. The objective lens can be a high NA objective (eg, having a NA of 0.90 or 0.95). The image field selection device 85 can include a lens 19, a concave mirror 71, an adjustable mirror array 72, and a lens 21. The image field selection device 85 can also include a controller 73 that is configured to adjust the adjustable mirror array 72. The adjustable mirror array can be a digital mirror device such as, for example, an XGA DLP wafer available from Texas Instruments. Also, other types of spatial light modulators (SLM) or microelectromechanical systems (MEMS) can be used instead of the adjustable mirror array 42. In an embodiment, the lenses 19, 21 may be omitted; the digital mirror device should then be positioned at the image plane of the objective.
在操作中，光源2經由透鏡元件25、照明界定孔徑27、透鏡元件26、12、干涉濾光器13、偏振器17、光束分光元件16及接物鏡15而將輻射光束發射至基板W上之目標部分30。照明界定孔徑27對於第1階疊對測量可為環形孔徑，或對於臨界(CD)重新建構之測量可為圓形孔徑。視基板W上之目標30之尺寸而定，可選擇環形環之不同尺寸或圓形孔徑之不同半徑。基板W上之經照明目標30經由透鏡15、光束分光元件16、18及影像場選擇器件85而將零階及更高階之碰撞光束散射至影像感測器22。通常，碰撞光束之光點幾何形狀界定經照明區域之形狀，其促進接物鏡15之光瞳平面的光瞳形狀。經照明區域可具有(例如)25μm直徑之圓形尺寸。其他形狀為(例如)矩形或正方形。透鏡21、19將此光瞳平面成像於影像感測器22上。影像感測器22可為(例如)CCD或CMOS影像感測器。在第一步驟中，控制器73可經由使用者介面(未圖示)而獲得影像場平面之對應於基板W處之選定目標30之部分的尺寸及位置。在另一步驟中，控制器73可調整數位鏡面器件72之第一數位鏡面群組，使得對應於中間影像場之選定部分的光束經由透鏡21而引導至影像感測器22，且調整數位鏡面器件72之第二數位鏡面群組，使得第二數位鏡面群組將對應於目標區域之非選定部分的光束引導至光束捕集器(未圖示)。In operation, the light source 2 emits a radiation beam onto the substrate W via the lens element 25, the illumination defining aperture 27, the lens elements 26, 12, the interference filter 13, the polarizer 17, the beam splitting element 16, and the objective lens 15. Target section 30. The illumination defining aperture 27 can be an annular aperture for the first order overlay measurement or a circular aperture for critical (CD) reconstruction. Depending on the size of the target 30 on the substrate W, different radii of different sizes or circular apertures of the annular ring may be selected. The illuminated target 30 on the substrate W scatters the zero-order and higher-order collision beams to the image sensor 22 via the lens 15, the beam splitting elements 16, 18, and the image field selecting device 85. Typically, the spot geometry of the colliding beam defines the shape of the illuminated region that promotes the pupil shape of the pupil plane of the objective lens 15. The illuminated area may have a circular size of, for example, a 25 [mu]m diameter. Other shapes are, for example, rectangular or square. The lenses 21, 19 image this pupil plane onto the image sensor 22. Image sensor 22 can be, for example, a CCD or CMOS image sensor. In a first step, the controller 73 can obtain the size and position of the portion of the image field plane corresponding to the selected target 30 at the substrate W via a user interface (not shown). In another step, the controller 73 adjusts the first digital mirror group of the integer position mirror device 72 such that the light beam corresponding to the selected portion of the intermediate image field is directed to the image sensor 22 via the lens 21, and the digital mirror is adjusted. The second digital mirror group of device 72 causes the second digital mirror group to direct a beam corresponding to a non-selected portion of the target region to a beam trap (not shown).
在另一實施例中，影像場界定元件75經配置以在影像場中界定與基板W上之第二預定部分相關聯之區域，使得第一預定部分與第二預定部分重疊且第二預定區域(未圖示)小於第一預定部分30。In another embodiment, the image field defining element 75 is configured to define an area associated with the second predetermined portion on the substrate W in the image field such that the first predetermined portion overlaps the second predetermined portion and the second predetermined portion (not shown) is smaller than the first predetermined portion 30.
在本文所描述之實施例中，測量光束中之影像場選定器件可與照明光束之直徑匹配，以便改良測量精確度且減少測量光束處之光子損耗。舉例而言，可以為30μm之光束直徑來照明晶粒內10x10μm目標以達成均一照明，且可以中間影像平面中之影像場選擇器件來空間地過濾經散射光。In the embodiments described herein, the image field selection device in the measurement beam can be matched to the diameter of the illumination beam to improve measurement accuracy and reduce photon loss at the measurement beam. For example, a 10x10 [mu]m target within the grain can be illuminated for a beam diameter of 30 [mu]m to achieve uniform illumination, and the image field selection device in the intermediate image plane can spatially filter the scattered light.
儘管在此本文中可特定地參考微影裝置在IC製造中之使用，但應理解，本文所描述之微影裝置可具有其他應用，諸如，製造積體光學系統、用於磁域記憶體之導引及偵測圖案、平板顯示器、液晶顯示器(LCD)、薄膜磁頭，等等。熟習此項技術者應瞭解，在該等替代應用之情境中，可認為本文對術語"晶圓"或"晶粒"之任何使用分別與更通用之術語"基板"或"目標部分"同義。可在曝光之前或之後在(例如)軌道(通常將抗蝕劑層施加至基板且顯影經曝光抗蝕劑之工具)、度量衡工具及/或度量衡工具中處理本文所提及之基板。適用時，可將本文之揭示應用於該等及其他基板處理工具。另外，可將基板處理一次以上，(例如)以便形成多層IC，使得本文所使用之術語基板亦可指代已經含有多個經處理層之基板。Although reference may be made herein specifically to the use of lithographic apparatus in IC fabrication, it should be understood that the lithographic apparatus described herein may have other applications, such as fabrication of integrated optical systems, for magnetic domain memory. Guide and detection patterns, flat panel displays, liquid crystal displays (LCDs), thin film heads, and more. Those skilled in the art will appreciate that any use of the terms "wafer" or "grain" herein is considered synonymous with the more general term "substrate" or "target portion", respectively, in the context of such alternative applications. The substrates referred to herein may be processed before or after exposure, for example, in a track (a tool that typically applies a layer of resist to the substrate and develops the exposed resist), a metrology tool, and/or a metrology tool. Where applicable, the disclosure herein can be applied to such and other substrate processing tools. Additionally, the substrate can be processed more than once, for example, to form a multi-layer IC, such that the term substrate as used herein may also refer to a substrate that already contains multiple processed layers.
儘管以上可特定地參考在光學微影術之情境中對本發明之實施例的使用，但應瞭解，本發明可用於其他應用(例如，壓印微影術)中，且在情境允許時不限於光學微影術。在壓印微影術中，圖案化器件中之構形界定形成於基板上之圖案。可將圖案化器件之構形壓入被供應至基板之抗蝕劑層中，在基板上，抗蝕劑藉由施加電磁輻射、熱、壓力或其組合而固化。在抗蝕劑固化之後，將圖案化器件移出抗蝕劑，從而在其中留下圖案。Although the above may be specifically referenced to the use of embodiments of the invention in the context of optical lithography, it will be appreciated that the invention may be used in other applications (eg, embossing lithography) and is not limited where context permits Optical lithography. In imprint lithography, the configuration in the patterned device defines a pattern formed on the substrate. The patterning device can be configured to be pressed into a resist layer that is supplied to the substrate where the resist is cured by application of electromagnetic radiation, heat, pressure, or a combination thereof. After the resist is cured, the patterned device is removed from the resist to leave a pattern therein.
術語"透鏡"在情境允許時可指代各種類型之光學組件中之任一者或組合，包括折射、反射、磁性、電磁及靜電光學組件。The term "lens", when the context permits, may refer to any or a combination of various types of optical components, including refractive, reflective, magnetic, electromagnetic, and electrostatic optical components.
儘管以上已描述本發明之特定實施例，但應瞭解，可以與所描述之方式不同的其他方式來實踐本發明。舉例而言，本發明可採取如下形式：電腦程式，其含有描述如以上所揭示之方法之機器可讀指令的一或多個序列；或資料儲存媒體(例如，半導體記憶體、磁碟或光碟)，其具有儲存於其中之該電腦程式。Although the specific embodiments of the invention have been described hereinabove, it is understood that the invention may be practiced otherwise than as described. For example, the invention can take the form of a computer program containing one or more sequences of machine readable instructions for describing a method as disclosed above; or a data storage medium (eg, a semiconductor memory, disk or optical disk) ), which has the computer program stored therein.
以上描述意欲為說明性而非限制性的。因此，對於熟習此項技術者而言將顯而易見的為，可在不脫離以下所闡明之申請專利範圍之範疇的情況下對如所描述之本發明進行修改。The above description is intended to be illustrative, and not restrictive. Therefore, it will be apparent to those skilled in the art that the invention as described herein may be modified without departing from the scope of the appended claims.
2．．．寬頻帶(白光)輻射投影儀/輻射源2. . . Broadband (white light) radiation projector / radiation source
4．．．分光計偵測器4. . . Spectrometer detector
10．．．光譜10. . . spectrum
11．．．背部投影式光瞳平面11. . . Back projection diaphragm plane
12．．．透鏡系統12. . . Lens system
13．．．干涉濾光器13. . . Interference filter
14．．．參考鏡面14. . . Reference mirror
15．．．顯微鏡接物鏡/透鏡系統15. . . Microscope objective lens/lens system
16．．．部分反射表面/光束分光元件16. . . Partially reflective surface/beam splitting element
17．．．偏振器17. . . Polarizer
18．．．光束分光器/光束分光元件18. . . Beam splitter/beam splitter
19．．．透鏡19. . . lens
20．．．透鏡20. . . lens
21．．．透鏡twenty one. . . lens
22．．．影像感測器twenty two. . . Image sensor
23．．．透鏡twenty three. . . lens
24．．．影像對準感測器twenty four. . . Image alignment sensor
25．．．透鏡系統25. . . Lens system
26．．．透鏡系統26. . . Lens system
27．．．照明界定孔徑27. . . Illumination defining aperture
28．．．孔徑28. . . Aperture
29．．．影像場選擇器件29. . . Image field selection device
30．．．目標部分/照明目標30. . . Target part / lighting target
40．．．散射計40. . . Scatterometer
41．．．全內反射稜鏡41. . . Total internal reflection
42．．．可調整鏡面陣列42. . . Adjustable mirror array
43．．．控制器43. . . Controller
50．．．可旋轉輪50. . . Rotatable wheel
51．．．圓形孔徑51. . . Circular aperture
52．．．圓形孔徑52. . . Circular aperture
53．．．圓形孔徑53. . . Circular aperture
54．．．正方形孔徑54. . . Square aperture
60．．．虹膜光闌60. . . Iris diaphragm
61．．．可移動葉片61. . . Movable blade
62．．．可移動葉片62. . . Movable blade
63．．．光闌之中心處或附近之孔徑63. . . Aperture at or near the center of the pupil
70．．．散射計70. . . Scatterometer
71．．．凹入鏡面71. . . Concave mirror
72．．．可調整鏡面陣列72. . . Adjustable mirror array
73．．．控制器73. . . Controller
75．．．影像場選擇器件75. . . Image field selection device
80．．．散射計80. . . Scatterometer
85．．．影像場選擇器件85. . . Image field selection device
AD．．．調整器AD. . . Adjuster
B．．．輻射光束B. . . Radiation beam
BD．．．光束傳送系統BD. . . Beam delivery system
BK．．．烘焙板BK. . . Baking board
C．．．目標部分C. . . Target part
CH．．．冷卻板CH. . . Cooling plate
CO．．．聚光器CO. . . Concentrator
D．．．偵測器D. . . Detector
DE．．．顯影器DE. . . Developer
F．．．焦距F. . . focal length
IF．．．位置感測器IF. . . Position sensor
IL．．．照明器IL. . . Illuminator
IN．．．積光器IN. . . Light concentrator
I/O1．．．輸入/輸出埠I/O1. . . Input/output埠
I/O2．．．輸入/輸出埠I/O2. . . Input/output埠
LA．．．微影裝置LA. . . Lithography device
LACU．．．微影控制單元LACU. . . Photographic control unit
LB．．．裝載盤LB. . . Loading tray
LC．．．微影單元LC. . . Photographic unit
M1．．．光罩對準標記M1. . . Mask alignment mark
M2．．．光罩對準標記M2. . . Mask alignment mark
MA．．．圖案化器件/光罩MA. . . Patterned device / reticle
MT．．．支撐結構MT. . . supporting structure
P1．．．基板對準標記P1. . . Substrate alignment mark
P2．．．基板對準標記P2. . . Substrate alignment mark
PL．．．投影系統PL. . . Projection system
PM．．．第一定位器PM. . . First positioner
PU．．．處理單元PU. . . Processing unit
PW．．．第二定位器PW. . . Second positioner
RO．．．機器人RO. . . robot
SC．．．旋塗器SC. . . Spin coater
SCS．．．監督控制系統SCS. . . Supervisory control system
SM1．．．散射計SM1. . . Scatterometer
SM2．．．散射計SM2. . . Scatterometer
SO．．．輻射源SO. . . Radiation source
TCU．．．軌道控制單元TCU. . . Track control unit
W．．．基板W. . . Substrate
WT．．．基板台WT. . . Substrate table
X．．．方向X. . . direction
Y．．．方向Y. . . direction
圖1a描繪微影裝置之一實施例；Figure 1a depicts an embodiment of a lithography apparatus;
圖1b描繪微影單元或叢集之一實施例；Figure 1b depicts an embodiment of a lithography unit or cluster;
圖2描繪散射計之一實施例；Figure 2 depicts an embodiment of a scatterometer;
圖3描繪散射計之一實施例；Figure 3 depicts an embodiment of a scatterometer;
圖4描繪散射計之一實施例；Figure 4 depicts an embodiment of a scatterometer;
圖5描繪具備可用於圖4之散射計之不同孔徑之輪的一實施例；Figure 5 depicts an embodiment with wheels of different apertures that can be used with the scatterometer of Figure 4;
圖6描繪可用於圖4之散射計之虹膜光闌的一實施例；Figure 6 depicts an embodiment of an iris diaphragm that can be used with the scatterometer of Figure 4;
圖7描繪散射計之一實施例；且Figure 7 depicts an embodiment of a scatterometer;
圖8描繪散射計之一實施例。Figure 8 depicts an embodiment of a scatterometer.
AD．．．調整器AD. . . Adjuster
B．．．輻射光束B. . . Radiation beam
BD．．．光束傳送系統BD. . . Beam delivery system
C．．．目標部分C. . . Target part
CO．．．聚光器CO. . . Concentrator
IF．．．位置感測器IF. . . Position sensor
IL．．．照明器IL. . . Illuminator
IN．．．積光器IN. . . Light concentrator
LA．．．微影裝置LA. . . Lithography device
M1．．．光罩對準標記M1. . . Mask alignment mark
M2．．．光罩對準標記M2. . . Mask alignment mark
MA．．．圖案化器件/光罩MA. . . Patterned device / reticle
MT．．．支撐結構MT. . . supporting structure
P1．．．基板對準標記P1. . . Substrate alignment mark
P2．．．基板對準標記P2. . . Substrate alignment mark
PL．．．投影系統PL. . . Projection system
PM．．．第一定位器PM. . . First positioner
PW．．．第二定位器PW. . . Second positioner
SO．．．輻射源SO. . . Radiation source
W．．．基板W. . . Substrate
WT．．．基板台WT. . . Substrate table
X．．．方向X. . . direction
Y．．．方向Y. . . direction
| Application Number | Priority Date | Filing Date | Title |
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| US919207P | 2007-12-27 | 2007-12-27 |
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| TW200935192A TW200935192A (en) | 2009-08-16 |
| TWI398739Btrue TWI398739B (en) | 2013-06-11 |
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| TW97151092ATWI398739B (en) | 2007-12-27 | 2008-12-26 | Metrology apparatus, lithographic apparatus and method of measuring a property of a substrate |
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| NL (1) | NL1036331A1 (en) |
| TW (1) | TWI398739B (en) |
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