TWI809782B - Pellicle inspection method and system thereof - Google Patents

Pellicle inspection method and system thereof Download PDF

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TWI809782B
TWI809782B TW111111506A TW111111506A TWI809782B TW I809782 B TWI809782 B TW I809782B TW 111111506 A TW111111506 A TW 111111506A TW 111111506 A TW111111506 A TW 111111506A TW I809782 B TWI809782 B TW I809782B
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pellicle
polarization state
photomask
light
information
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TW202338327A (en
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陳明彰
張俊霖
陳家楨
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台灣積體電路製造股份有限公司
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  • Preparing Plates And Mask In Photomechanical Process (AREA)

Abstract

A pellicle inspection method includes measuring a plurality of regions of a pellicle to obtain a first polarization-state information and a second polarization-state information of each of the regions by a low-coherence interference system using a first polarized light and a second polarized light, wherein a polarization state of the first polarized light is different from a polarization state of the second polarized light; calculating the first polarization-state information and the second polarization-state information of each of the regions to determine if the pellicle is qualified; and mounting the qualified pellicle onto a reticle.

Description

光罩護膜檢測方法及其系統Photomask protective film detection method and system

本揭露是關於光罩護膜檢測方法及其系統。The present disclosure relates to a photomask pellicle inspection method and a system thereof.

光罩護膜（pellicle）是一透明薄膜，其蒙在一框體上，該框體黏固於光罩的一側上以保護光罩免於毀損、灰塵以及/或潮濕。在極紫外光微影技術中，光罩護膜在極紫外光波長區域具有高透明度、高機械強度以及低熱膨脹的特性。A pellicle is a transparent film that covers a frame that is glued to one side of the reticle to protect the reticle from damage, dust, and/or moisture. In EUV lithography, the photomask pellicle has high transparency, high mechanical strength and low thermal expansion in the EUV wavelength region.

根據本揭露的部分實施方式中，光罩護膜檢測方法包含以一低同調光干涉系統，分別使用一第一偏振光以及一第二偏振光，量測一光罩護膜的複數個區域，以分別獲得每一該些區域的一第一偏振態色散資訊以及一第二偏振態色散資訊，其中該第一偏振光的偏振態不同於該第二偏振光的偏振態；計算每一該些區域的該第一偏振態色散資訊以及該第二偏振態色散資訊，以判斷該光罩護膜是否合格；以及將合格的該光罩護膜裝設至一光罩上。According to some embodiments of the present disclosure, the method for inspecting a pellicle includes measuring a plurality of regions of a pellicle by using a low-coherence optical interference system, respectively using a first polarized light and a second polarized light, To respectively obtain a first polarization state dispersion information and a second polarization state dispersion information of each of the regions, wherein the polarization state of the first polarized light is different from the polarization state of the second polarized light; calculate each of the The first polarization state dispersion information and the second polarization state dispersion information of the area to judge whether the mask pellicle is qualified; and install the qualified mask pellicle on a photomask.

根據本揭露的部分實施方式中，光罩護膜檢測方法包含以一低同調光干涉系統，量測一光罩護膜的複數個區域，以獲得每一該些區域的一群組延遲頻譜；計算每一該些區域的該群組延遲頻譜，以判斷該光罩護膜是否合格；以及將合格的該光罩護膜裝設至一光罩上。According to some embodiments of the present disclosure, the pellicle detection method includes measuring a plurality of regions of a pellicle with a low-coherence optical interferometry system to obtain a group delay spectrum of each of the regions; calculating the group delay spectrum of each of the regions to judge whether the photomask pellicle is qualified; and installing the qualified photomask pellicle on a photomask.

根據本揭露的部分實施方式中，光罩護膜檢測系統包含白光光源、複數個干涉儀光學組件、光譜儀感測器、偏振片組件以及處理器。干涉儀光學組件用以結合一物件光以及一參考光，其中該物件光以及該參考光來自該白光光源。光譜儀感測器用以紀錄一干涉資訊。偏振片組件用以控制該物件光以及該參考光係為一第一偏振態或一第二偏振態。處理器電性連接該低同調光干涉系統之該光譜儀感測器以及該偏振片組件。該處理器用以：使該物件光以及該參考光係為第一偏振態，取得一第一干涉資訊；使該物件光以及該參考光係為第二偏振態，取得一第二干涉資訊；分析該第一干涉資訊以及該第二干涉資訊，以分別獲得一第一偏振態色散資訊以及一第二偏振態色散資訊；計算該第一偏振態色散資訊以及該第二偏振態色散資訊，以判斷該光罩護膜是否合格。According to some embodiments of the present disclosure, the pellicle inspection system includes a white light source, a plurality of interferometer optical components, a spectrometer sensor, a polarizer component, and a processor. The interferometer optical component is used for combining an object light and a reference light, wherein the object light and the reference light come from the white light source. The spectrometer sensor is used to record an interference information. The polarizer assembly is used to control the object light and the reference light to be a first polarization state or a second polarization state. The processor is electrically connected to the spectrometer sensor and the polarizer assembly of the low-coherence optical interference system. The processor is used to: make the object light and the reference light be in a first polarization state to obtain a first interference information; make the object light and the reference light be in a second polarization state to obtain a second interference information; analyze the first interference information and the second interference information to respectively obtain a first polarization state dispersion information and a second polarization state dispersion information; calculate the first polarization state dispersion information and the second polarization state dispersion information to judge Whether the photomask protective film is qualified.

以下揭露內容提供了許多不同的實施例或實例，以用於實施所提供的主題的不同特徵。下文描述元件及配置的特定實例以簡化本揭露。當然，這些特定實例僅為實例，而不旨在進行限制。例如，在以下描述中第一特徵在第二特徵上方或上的形成可以包含第一特徵及第二特徵直接接觸地形成的實施例，且亦可以包含額外特徵可以形成於第一特徵與第二特徵之間以使得第一特徵及第二特徵可以不直接接觸的實施例。另外，本揭露可以在各種實例中重複附圖標記及/或字母。此重複係出於簡單及清楚的目的，且其本身並不指示所論述的各種實施例及/或組態之間的關係。The following disclosure provides many different embodiments, or examples, for implementing different features of the presented subject matter. Specific examples of components and configurations are described below to simplify the present disclosure. These specific examples are, of course, examples only and are not intended to be limiting. For example, the formation of a first feature on or on a second feature in the following description may include embodiments in which the first feature and the second feature are formed in direct contact, and may also include that additional features may be formed on the first feature and the second feature. An embodiment in which the features are such that the first feature and the second feature may not be in direct contact. Additionally, the present disclosure may repeat reference numerals and/or letters in various instances. This repetition is for simplicity and clarity and by itself does not indicate a relationship between the various embodiments and/or configurations discussed.

另外，為了便於描述，本文中可以使用空間相對術語（例如「在...之下」、「在...下方」、「底部」、「在...上方」、「上部」及其類似者），以描述如圖式中所圖示的一個部件或特徵與另一部件或特徵的關係。除了在圖式中所描繪的定向之外，空間相對術語亦旨在涵蓋裝置在使用或操作中的不同定向。設備可以以其他方式定向（旋轉90度或處於其他定向），且因此可以相應地解釋本文中所使用的空間相對描述詞。In addition, spatially relative terms (eg, "under", "beneath", "bottom", "above", "upper" and the like may be used herein for ease of description) or) to describe the relationship of one component or feature to another component or feature as illustrated in the drawings. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

本揭露的部分實施方式提供了一種檢測光罩護膜的方法，可透過低同調干涉儀（low-coherence interferometry），例如白光干涉儀（white light interferometry；WLI），而對光罩護膜進行檢測。低同調干涉法（例如白光干涉法）是一種非接觸式光學方法，用於以奈米級解析度測量折射率和厚度。干涉測量利用波疊加原理來組合波，從而使它們的組合結果從這些瞬時波前提取信息。當兩個波結合時，產生的圖案由兩個波之間的相位差決定，同相的波會受到建設性干涉，而異相的波會受到破壞性干涉。這將是表現材料的色散特性的一種有效方法。通過表現薄膜在不同入射偏振下的色散特性，可以映射（map）厚度並反映局部應力。藉此，可判斷光罩護膜的局部應力情況，以降低光罩護膜破裂造成的損失。Some embodiments of the present disclosure provide a method for inspecting a pellicle, which can be inspected by a low-coherence interferometry (low-coherence interferometry), such as a white light interferometry (WLI). . Low-coherence interferometry, such as white light interferometry, is a non-contact optical method for measuring refractive index and thickness with nanometer-scale resolution. Interferometry uses the principle of wave superposition to combine waves such that their combined result extracts information from these instantaneous wave fronts. When two waves combine, the resulting pattern is determined by the phase difference between the two waves, with waves that are in phase interfere constructively and waves that are out of phase interfere destructively. This would be an efficient way to represent the dispersion properties of materials. By characterizing the dispersion properties of the film under different incident polarizations, it is possible to map thickness and reflect local stress. Thereby, the local stress condition of the pellicle can be judged, so as to reduce the loss caused by the rupture of the pellicle.

圖1為根據本揭露部分實施方式的微影系統100的示意圖。微影系統100也可被稱為掃描儀，其可操作以利用相應的輻射源和曝光模式進行微影曝光製程。在部分實施方式中，微影系統100可以是極紫外（extreme ultra violet；EUV）光微影系統。微影系統100可包含輻射源110、照射器120、用以接收光罩210的光罩台130、投影光學模組140及用以接收半導體基板W的基板台150。微影系統100的操作的一般描述如下：來自輻射源110的EUV光被導向照射器120，進而被投射至光罩210上。光罩210反射的EUV光攜帶有曝光圖案，該EUV光被導向投影光學模組140，投影光學模組140聚焦EUV光且將EUV光投影至半導體基板W上以曝光沉積在其上的光阻層。FIG. 1 is a schematic diagram of a lithography system 100 according to some embodiments of the present disclosure. The lithography system 100 may also be referred to as a scanner, which is operable to perform a lithography exposure process using a corresponding radiation source and exposure mode. In some embodiments, the lithography system 100 may be an extreme ultraviolet (extreme ultra violet; EUV) photolithography system. The lithography system 100 may include a radiation source 110 , an illuminator 120 , a mask stage 130 for receiving the mask 210 , a projection optical module 140 and a substrate stage 150 for receiving the semiconductor substrate W. A general description of the operation of the lithography system 100 is as follows: EUV light from the radiation source 110 is directed to the illuminator 120 and then projected onto the reticle 210 . The EUV light reflected by the mask 210 carries the exposure pattern, and is directed to the projection optics module 140, which focuses the EUV light and projects the EUV light onto the semiconductor substrate W to expose the photoresist deposited thereon. layer.

於部分實施方式中，輻射源110可用於產生EUV光。輻射源110可以利用雷射產生電漿（laser produced plasma；LPP）等機制來產生EUV輻射。在部分實施方式中，EUV光可以包含具有範圍介於約1nm至約100nm的波長的光。在一個特定實例中，輻射源110產生具有以約13.5nm為中心的波長的EUV光。因此，輻射源110亦可以稱為EUV輻射源110。In some embodiments, the radiation source 110 can be used to generate EUV light. The radiation source 110 may utilize mechanisms such as laser produced plasma (LPP) to generate EUV radiation. In some embodiments, the EUV light can comprise light having a wavelength ranging from about 1 nm to about 100 nm. In one particular example, radiation source 110 generates EUV light having a wavelength centered at about 13.5 nm. Therefore, the radiation source 110 may also be referred to as the EUV radiation source 110 .

於部分實施方式中，照射器120可以包含反射光學器件，例如單個鏡子或具有多個鏡子的鏡子系統，以便將來自輻射源110的光引導至光罩台130。光罩台130可用以將光罩組件200固定在微影系統100內。光罩台130可以包含靜電卡盤（electrostatic chuck；e-chuck）以固定光罩組件200。藉此，照射器120可將來自輻射源110的光引導至光罩組件200。In some embodiments, illuminator 120 may include reflective optics, such as a single mirror or a mirror system of multiple mirrors, to direct light from radiation source 110 to mask table 130 . The mask stage 130 can be used to fix the mask assembly 200 in the lithography system 100 . The reticle table 130 may include an electrostatic chuck (e-chuck) to fix the reticle assembly 200 . Thereby, the illuminator 120 can guide the light from the radiation source 110 to the mask assembly 200 .

於部分實施方式中，光罩組件200包含光罩210、光罩護膜（pellicle）220以及框架230。光罩210可包含適當的反射性圖案212。光罩護膜220可置放在光罩210的圖案化側上方並與光罩210隔開，以保護光罩210在放置及曝光期間免受污染。光罩護膜220可選用具EUV高透射率及穩定性的材料。舉例而言，光罩護膜220可包含無機材料，例如石墨烯、單晶矽、多晶矽、氮化矽或其他適當材料。或者，光罩護膜220可包含有機材料，例如樹脂。光罩護膜220保護光罩210免受不想要的顆粒的影響，這些顆粒可以以其他方式對圖案轉印至晶圓的保真度產生負面影響。框架230用以將光罩護膜220適當地固定至光罩210。框架230可以設計成各種尺寸、形狀及組態。在部分實施方式中，框架230可以具有圓形形狀、矩形形狀或任何其他適合的形狀。框架230可以包含具有足夠機械強度的剛性材料。舉例而言，框架230的材料可包含但不限於鋁（Al）、鋁合金、鈦（Ti）、鎳（Ni）、金（Au）、銀（Ag）、銅（Cu）、鉬（Mo）、鉑（Pt）、鉻（Cr）、錳（Mn）、鐵（Fe）、鈷（Co）、鈀（Pd）、鉭（Ta）、鎢（W）、矽、聚合物、其他適合的材料及/或其組合。在部分實施方式中，框架230可以包含多孔材料。In some embodiments, the photomask assembly 200 includes a photomask 210 , a photomask pellicle 220 and a frame 230 . The photomask 210 may contain a suitable reflective pattern 212 . A pellicle 220 may be placed over the patterned side of the reticle 210 and spaced from the reticle 210 to protect the reticle 210 from contamination during placement and exposure. The photomask pellicle 220 can be selected from materials with high EUV transmittance and stability. For example, the pellicle 220 may include inorganic materials such as graphene, monocrystalline silicon, polycrystalline silicon, silicon nitride, or other suitable materials. Alternatively, the pellicle 220 may include organic materials such as resins. The reticle pellicle 220 protects the reticle 210 from unwanted particles that may otherwise negatively impact the fidelity with which the pattern is transferred to the wafer. The frame 230 is used for properly fixing the photomask pellicle 220 to the photomask 210 . The frame 230 can be designed in various sizes, shapes and configurations. In some embodiments, frame 230 may have a circular shape, a rectangular shape, or any other suitable shape. The frame 230 may comprise a rigid material with sufficient mechanical strength. For example, the material of the frame 230 may include but not limited to aluminum (Al), aluminum alloy, titanium (Ti), nickel (Ni), gold (Au), silver (Ag), copper (Cu), molybdenum (Mo) , platinum (Pt), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), palladium (Pd), tantalum (Ta), tungsten (W), silicon, polymers, other suitable materials and/or combinations thereof. In some embodiments, frame 230 may comprise a porous material.

光罩護膜220可由框架黏著劑附接至框架230。框架黏著劑可包含熱固性黏著劑材料，例如環氧樹脂、丙烯酸樹脂、氟樹脂、苯並環丁烯（benzocyclobutene；BCB）、甲基矽倍半氧烷（methylsilsesquioxane；MSQ）、聚醯亞胺（polyimide；PI）、其他熱固性材料及/或其組合。在部分實施方式中，框架黏著劑可包含膠水或其他材料。The pellicle 220 may be attached to the frame 230 by a frame adhesive. The frame adhesive may include thermosetting adhesive materials such as epoxy resin, acrylic resin, fluororesin, benzocyclobutene (BCB), methylsilsesquioxane (MSQ), polyimide ( polyimide; PI), other thermosetting materials and/or combinations thereof. In some embodiments, the frame adhesive may comprise glue or other materials.

框架230可由適當黏著劑附接至光罩210的前側表面。此黏著劑可以包含與前述框架黏著劑相同或不同的材料。此黏著劑可以包含熱固性黏著劑材料，諸如例如環氧樹脂、丙烯酸樹脂、氟樹脂、BCB、MSQ或PI。在部分其他實施例中，框架230可以透過例如至少一個吸盤、真空或靜電貼紙的方式附接至光罩210的前側表面，而不同於黏著劑固定方式，而省略黏著劑。The frame 230 may be attached to the front side surface of the reticle 210 by a suitable adhesive. This adhesive may comprise the same or different material than the aforementioned frame adhesive. This adhesive may comprise a thermosetting adhesive material such as, for example, epoxy resin, acrylic resin, fluororesin, BCB, MSQ or PI. In some other embodiments, the frame 230 may be attached to the front surface of the photomask 210 by means such as at least one suction cup, vacuum or electrostatic stickers, instead of the adhesive fixing method, and the adhesive is omitted.

EUV光自光罩210的反射性圖案212反射且被導向投影光學模組140。投影光學模組140可為投影光學盒（projection optics box；POB）。投影光學模組140可以包含反射光學器件，例如單個鏡子或具有多個鏡子的鏡子系統。投影光學模組140收集自光罩210反射的EUV光，且將光罩210定義的圖案成像至固定在微影系統100的基板台150上的半導體基板W上，以曝光在半導體基板W上的EUV光阻層。The EUV light is reflected from the reflective pattern 212 of the reticle 210 and directed to the projection optical module 140 . The projection optics module 140 may be a projection optics box (POB). Projection optics module 140 may contain reflective optics, such as a single mirror or a mirror system with multiple mirrors. The projection optical module 140 collects the EUV light reflected from the mask 210, and images the pattern defined by the mask 210 onto the semiconductor substrate W fixed on the substrate stage 150 of the lithography system 100 to expose the light on the semiconductor substrate W. EUV photoresist layer.

基板台150用以固定待圖案化的半導體基板W。在各種實施方式中，半導體基板W包含半導體晶圓，例如矽晶圓、鍺晶圓、矽鍺晶圓、III-V晶圓或其他類型的晶圓。半導體基板W可以塗佈有對EUV光敏感的光阻層（例如EUV光阻層）。在各種實施例中，微影系統100的各個組件（例如輻射源110、照射器120、光罩台130、投影光學模組140及基板台150）可以容納在高真空環境中且因此在高真空環境中操作，以減少EUV光的大氣吸收。The substrate stage 150 is used to fix the semiconductor substrate W to be patterned. In various embodiments, the semiconductor substrate W includes a semiconductor wafer, such as a silicon wafer, a germanium wafer, a silicon germanium wafer, a III-V wafer, or other types of wafers. The semiconductor substrate W may be coated with a photoresist layer sensitive to EUV light (eg, an EUV photoresist layer). In various embodiments, the various components of lithography system 100 (eg, radiation source 110, illuminator 120, reticle stage 130, projection optics module 140, and substrate stage 150) may be housed in a high vacuum environment and thus operate under high vacuum. environment to minimize atmospheric absorption of EUV light.

光罩護膜220可能存在應力不均的區域。應力可以是外在的，例如外加應力、熱膨脹和塑性變形，也可以是內在的，例如生長形態、晶格失配、相變等。圖2A為根據本揭露部分實施方式的光罩護膜220的示意圖。示意圖中，光罩護膜220包含了多個粒子222，各個粒子222之間存在鍵結224。這些光罩護膜220的粒子222分布可能會受到各向異性（anisotropic）的應力影響。The pellicle 220 may have areas of uneven stress. Stress can be extrinsic, such as applied stress, thermal expansion, and plastic deformation, or intrinsic, such as growth morphology, lattice mismatch, phase transition, etc. FIG. 2A is a schematic diagram of a pellicle 220 according to some embodiments of the present disclosure. In the schematic diagram, the pellicle 220 includes a plurality of particles 222 , and there are bonds 224 between the particles 222 . The particle 222 distribution of the pellicle 220 may be affected by anisotropic stress.

在本實施例中，光罩護膜220受到方向X的應力。換句話說，方向X的拉力大於方向Y的拉力。在此情況下，粒子222之間在方向X上的鍵結224被延伸，粒子222之間在方向Y上的鍵結224保持不變，而使粒子222在方向X上的距離大於粒子222在方向Y上的距離。此粒子222分布差異可能影響光罩護膜220的雙折射性，例如造成光罩護膜220在不同偏振態（例如沿方向X的偏振態以及沿方向Y的偏振態）下的折射率差異。In this embodiment, the pellicle 220 is subjected to stress in the direction X. In other words, the pulling force in direction X is greater than the pulling force in direction Y. In this case, the bond 224 between the particles 222 in the direction X is extended, the bond 224 between the particles 222 in the direction Y remains unchanged, and the distance between the particles 222 in the direction X is greater than that of the particles 222 in The distance in direction Y. This difference in the particle 222 distribution may affect the birefringence of the pellicle 220 , eg, cause a difference in the refractive index of the pellicle 220 under different polarization states (eg, along direction X and along direction Y).

圖2B繪示根據本揭露部分實施方式的光罩護膜220的折射率對波長關係圖。在圖2B中，橫軸為波長，縱軸為折射率。同時參考圖2A與圖2B。具體而言，光線可包含一第一偏振光L p以及/或一第二偏振光L s，第一偏振光L p與第二偏振光L s可為線性偏振光，且兩者偏振方向不同。於部分實施方式中，第一偏振光L p與第二偏振光L s的偏振方向互相垂直。於部分實施方式中，第一偏振光L p與第二偏振光L s的偏振方向分別平行於方向X與方向Y。光罩護膜220對於第一偏振光L p具有折射率n p，光罩護膜220對於第二偏振光L s具有折射率n s。受到方向X的應力，光罩護膜220對於第一偏振光L p的折射率n p不同於光罩護膜220對於第二偏振光L s的折射率n s，兩者之間存在折射率差dn。如圖所示，此折射率差dn可隨著光線頻譜而有差異。在本實施方式中，折射率n s大於折射率n p。於其他實施方式中，折射率n p可大於折射率n s。 FIG. 2B is a graph showing the relationship between the refractive index and the wavelength of the pellicle 220 according to some embodiments of the present disclosure. In FIG. 2B , the horizontal axis represents the wavelength, and the vertical axis represents the refractive index. Refer to FIG. 2A and FIG. 2B simultaneously. Specifically, the light may include a first polarized light L p and/or a second polarized light L s , the first polarized light L p and the second polarized light L s may be linearly polarized light, and the polarization directions of the two are different. . In some implementations, the polarization directions of the first polarized light L p and the second polarized light L s are perpendicular to each other. In some embodiments, the polarization directions of the first polarized light L p and the second polarized light L s are parallel to the direction X and the direction Y, respectively. The pellicle 220 has a refractive index n p for the first polarized light L p , and the pellicle 220 has a refractive index n s for the second polarized light L s . Under the stress in the direction X, the refractive index n p of the pellicle 220 for the first polarized light L p is different from the refractive index n s of the pellicle 220 for the second polarized light L s , and there is a refractive index between them Poor dn. As shown, this refractive index difference dn may vary with the light spectrum. In this embodiment, the refractive index n s is greater than the refractive index n p . In other embodiments, the refractive index n p may be greater than the refractive index n s .

當光罩護膜220局部應力不均的情況過於嚴重時，在微影過程中受到高溫破壞、含氫氣體的侵蝕，光罩護膜220可能會在曝光的過程中於微影系統100中破裂。當光罩護膜220在微影系統100中破裂後，後續須再清潔微影系統100的腔室、清潔或重新製備光罩、重新啟用微影系統100等。這些步驟會造成長時間停機，成本甚鉅。When the local stress unevenness of the pellicle 220 is too severe, the pellicle 220 may be broken in the lithography system 100 during the exposure process due to high temperature damage and hydrogen-containing gas erosion during the lithography process. . After the photomask pellicle 220 is broken in the lithography system 100 , the chamber of the lithography system 100 must be cleaned, the photomask must be cleaned or re-prepared, and the lithography system 100 must be restarted. These steps cause long and costly downtime.

於本揭露的部分實施方式中，藉由以下所示的檢測方法M（參考圖3）以及低同調光干涉檢測系統300（參考圖4A），可在微影系統100（參考圖1）之外，離線（off-line）檢測光罩護膜220。透過檢測光罩護膜220各區域的雙折射性，可以推估其各區域所受的機械應力，以得知光罩護膜220的應力分布以及均勻性。藉此，可預先篩去應力分布不佳的光罩護膜220，避免光罩護膜220在微影系統100的腔室內破裂，而須長時間停機的情況。In some embodiments of the present disclosure, by using the detection method M shown below (refer to FIG. 3 ) and the low-coherence optical interference detection system 300 (refer to FIG. 4A ), it is possible to , the photomask pellicle 220 is detected off-line. By detecting the birefringence of each region of the pellicle 220 , the mechanical stress on each region can be estimated, so as to know the stress distribution and uniformity of the pellicle 220 . Thereby, the pellicle 220 with poor stress distribution can be screened out in advance, so as to avoid the situation that the pellicle 220 breaks in the chamber of the lithography system 100 and needs to be shut down for a long time.

圖3為根據本揭露部分實施方式的檢測方法M的流程圖。檢測方法M包含步驟S1~S10。在步驟S1，從存放區，取得一光罩護膜。在步驟S2，對該光罩護膜，進行一光學檢測分析。在步驟S3，根據該光學檢測分析的結果是否合格，決定進行步驟S4或S4’。 在步驟S4’，棄置該不合格的光罩護膜，並回到步驟S1。在步驟S4，將該合格的光罩護膜，安裝至光罩上，以構成光罩組件。在步驟S5，將光罩組件，安裝至微影系統上，以進行光刻微影製程。在步驟S6，從微影系統上，卸下該光罩組件。在步驟S7，對該光罩護膜，進行一光學檢測分析。在步驟S8，根據該光學檢測分析的結果是否合格，決定進行步驟S9或S4’。在步驟S9，將該光罩護膜放置於暫存區。在步驟S10，從暫存區，取出該光罩護膜，並回到步驟S2。應了解到，可以在步驟S1~S10之前、之中以及之後加入額外的步驟，且對於該方法的另一部份實施方式，以下提到的部分步驟可以被取代或取消。步驟/程序的順序可以被改變。FIG. 3 is a flowchart of a detection method M according to some embodiments of the present disclosure. The detection method M includes steps S1-S10. In step S1, a pellicle is obtained from the storage area. In step S2, an optical detection analysis is performed on the pellicle. In step S3, according to whether the result of the optical detection analysis is qualified, it is decided to carry out step S4 or S4'. In step S4', discard the unqualified photomask pellicle, and return to step S1. In step S4, the qualified photomask pellicle is mounted on the photomask to form a photomask assembly. In step S5, the photomask assembly is installed on the lithography system to perform photolithography and lithography process. In step S6, the photomask assembly is removed from the lithography system. In step S7, an optical detection analysis is performed on the mask pellicle. In step S8, according to whether the result of the optical detection analysis is qualified, it is decided to carry out step S9 or S4'. In step S9, the photomask pellicle is placed in a temporary storage area. In step S10, take out the photomask pellicle from the temporary storage area, and return to step S2. It should be understood that additional steps can be added before, during and after steps S1˜S10, and for another partial implementation of the method, some of the steps mentioned below can be replaced or eliminated. The order of steps/procedures can be changed.

首先，在步驟S1，從存放區中，取得一光罩護膜。於部分實施方式中，可以由適當方法製得多個光罩護膜，並批量地儲存在存放區。或者，可從製造廠商購得多個光罩護膜，並批量地儲存在存放區。Firstly, in step S1, a pellicle is obtained from the storage area. In some embodiments, a plurality of pellicles can be produced by appropriate methods and stored in batches in a storage area. Alternatively, multiple pellicles can be purchased from the manufacturer and stored in bulk in a storage area.

接著，在步驟S2，對該光罩護膜，進行一光學檢測分析。此光學檢測分析可以透過後述的低同調光干涉檢測系統300（參照圖4A）進行。舉例而言，透過後述的低同調光干涉檢測系統300（參照圖4A），可獲得光罩護膜220的每一區域220R（參考圖4B）的一第一偏振態色散資訊以及一第二偏振態色散資訊，進而了解每一區域220R（參考圖4B）的應力情況。其中，可以分析取得光罩護膜220的各個區域220R（參考圖4B）的第一偏振態色散資訊與第二偏振態色散資訊之間的偏振態色散資訊差以及偏振態色散資訊差的梯度（偏振態色散資訊差對位置的微分）。又一例而言，透過該低同調光干涉檢測系統300（參照圖4A），可獲得光罩護膜220的每一區域220R（參考圖4B）的厚度資訊，進而了解光罩護膜的平整度。Next, in step S2, an optical detection analysis is performed on the pellicle. This optical detection analysis can be performed through a low-coherence optical interference detection system 300 (refer to FIG. 4A ) described later. For example, a first polarization state dispersion information and a second polarization state dispersion information of each region 220R (refer to FIG. 4B ) of the mask pellicle 220 can be obtained through the low-coherence optical interference detection system 300 (refer to FIG. 4A ) described later. State dispersion information, and then understand the stress of each region 220R (refer to FIG. 4B ). Wherein, the polarization state dispersion information difference between the first polarization state dispersion information and the second polarization state dispersion information and the gradient of the polarization state dispersion information difference ( Differentiation of polarization state dispersion information difference with respect to position). As another example, through the low-coherent optical interference detection system 300 (see FIG. 4A ), the thickness information of each region 220R (see FIG. 4B ) of the pellicle 220 can be obtained, so as to understand the flatness of the pellicle .

色散是指材料的折射率隨波長而變化的特性。不同波長的光在真空中行進的速度是相同的，但當進入材料時，會因材料的特性造成傳輸速度上的差異，稱之為色散。在本揭露的部分實施方式中，所量測的色散資訊以群組延遲（group delay）頻譜為例。群組延遲是指光在材料中的時間延遲。群組延遲頻譜中不同波長的延遲差異反映了色散現象。於其他實施方式中，也可透過其他系統量測其他能反應色散現象的資訊，作為色散資訊。Dispersion refers to the property that the refractive index of a material varies with wavelength. Light with different wavelengths travels at the same speed in a vacuum, but when it enters a material, it will cause a difference in transmission speed due to the characteristics of the material, which is called dispersion. In some embodiments of the present disclosure, the measured dispersion information takes a group delay spectrum as an example. Group delay refers to the time delay of light in a material. The difference in delay at different wavelengths in the group delay spectrum reflects the phenomenon of chromatic dispersion. In other embodiments, other information that can reflect the dispersion phenomenon can also be measured by other systems as the dispersion information.

在步驟S3，根據該光學檢測分析的結果是否合格，決定進行步驟S4或S4’。於部分實施方式中，可以依據上述偏振態色散資訊差、偏振態色散資訊差的梯度以及/或厚度資訊，判斷光罩護膜220是否合格。In step S3, according to whether the result of the optical detection analysis is qualified, it is decided to carry out step S4 or S4'. In some embodiments, whether the photomask pellicle 220 is qualified or not can be judged according to the above polarization state dispersion information difference, the gradient of the polarization state dispersion information difference, and/or the thickness information.

舉例而言，在以偏振態色散資訊差為準的實施例中，當光罩護膜220的偏振態色散資訊差的變異係數小於等於一預定值時，判斷光罩護膜220是否合格；變異係數大於該預定值時，判斷光罩護膜220是否不合格。該預定值時的範圍可以在大約2%至大約60%之間。For example, in the embodiment based on the polarization state dispersion information difference, when the coefficient of variation of the polarization state dispersion information difference of the photomask pellicle 220 is less than or equal to a predetermined value, it is judged whether the photomask pellicle 220 is qualified; When the coefficient is greater than the predetermined value, it is judged whether the pellicle 220 is unqualified. The predetermined value may range from about 2% to about 60%.

又舉例而言，在以偏振態色散資訊差的梯度為準的實施例中，當光罩護膜220的偏振態色散資訊差的梯度的變異係數小於等於一預定值時，判斷光罩護膜220是否合格；變異係數大於該預定值時，判斷光罩護膜220是否不合格。該預定值時的範圍可以在大約2%至大約60%之間。For another example, in the embodiment where the gradient of the polarization state dispersion information difference is used as the criterion, when the coefficient of variation of the gradient of the polarization state dispersion information difference of the mask pellicle 220 is less than or equal to a predetermined value, it is judged that the mask pellicle 220 is qualified; when the coefficient of variation is greater than the predetermined value, it is judged whether the pellicle 220 is unqualified. The predetermined value may range from about 2% to about 60%.

再舉例而言，在以厚度資訊為準的實施例中，當光罩護膜220的厚度資訊的變異係數小於等於一預定值時，判斷光罩護膜220是否合格；變異係數大於該預定值時，判斷光罩護膜220是否不合格。該預定值時的範圍可以在大約2%至大約60%之間。For another example, in the embodiment based on the thickness information, when the coefficient of variation of the thickness information of the pellicle 220 is less than or equal to a predetermined value, it is judged whether the pellicle 220 is qualified; the coefficient of variation is greater than the predetermined value , it is judged whether the pellicle 220 is unqualified. The predetermined value may range from about 2% to about 60%.

上述實施方式的判斷方式僅以變異係數為例。於其他實施方式中，也可採用其他條件作為判斷光罩護膜合格與否的基準。舉例而言，於部分其他實施方式中，可透過計算數值的平均值以及上下限（可後續參考圖8A至8C），來作為合格與否的基準。The judgment method in the above embodiment only takes the coefficient of variation as an example. In other embodiments, other conditions may also be used as a criterion for judging whether the photomask pellicle is qualified or not. For example, in some other implementations, the average value and the upper and lower limits of the values (referring to FIGS. 8A to 8C ) can be used as the criteria for passing or failing.

當判斷該光學檢測分析的結果為不合格時，進行步驟S4’，棄置該不合格的光罩護膜220，並回到步驟S1。藉此，從存放區，取得另一個光罩護膜重新進行檢測。When it is judged that the result of the optical detection analysis is unqualified, proceed to step S4', discard the unqualified photomask pellicle 220, and return to step S1. In this way, another photomask pellicle is obtained from the storage area for retesting.

當判斷該光學檢測分析的結果為合格時，進行步驟S4，將合格的該光罩護膜220，安裝至光罩210上。此步驟可包含將光罩護膜220黏貼至前述的框架230（參考圖1）、將框架230（參考圖1）黏貼至光罩210等，進而構成光罩組件200（參考圖1）。When it is judged that the result of the optical inspection and analysis is qualified, step S4 is performed to mount the qualified photomask pellicle 220 on the photomask 210 . This step may include adhering the pellicle film 220 to the aforementioned frame 230 (refer to FIG. 1 ), adhering the frame 230 (refer to FIG. 1 ) to the reticle 210 , etc., thereby forming the reticle assembly 200 (refer to FIG. 1 ).

在步驟S5，將光罩組件200（參考圖1），安裝至微影系統上，以進行光刻微影製程。可以將光罩組件200（例如安裝有光罩護膜220的光罩210）固定至微影系統100的光罩台130（參考圖1），透過光罩組件200反射EUV光，對適當晶圓進行光刻微影製程。In step S5 , the photomask assembly 200 (refer to FIG. 1 ) is mounted on a lithography system to perform a photolithography process. A reticle assembly 200 (such as a reticle 210 mounted with a pellicle 220 ) can be fixed to the reticle stage 130 (refer to FIG. 1 ) of the lithography system 100 , and the EUV light can be reflected through the reticle assembly 200 , for an appropriate wafer. Perform photolithography process.

在完成一或多個梯次的光刻微影製程後，微影系統可能需進行維修保養或改用其他光罩組件進行曝光。此時，可以進行步驟S6，微影系統中卸下光罩組件200（參考圖1）。有鑑於光刻微影製程中，光罩護膜可能受到高溫、氫氣等的破壞打斷鍵，導致應力以及/或厚度變化。此時，如步驟S7，可以對卸下的光罩組件200的光罩護膜220（參考圖1），進行光學檢測分析。步驟S7的光學檢測分析大致如同前述步驟S2所述，在此不再贅述。After completing one or more stages of photolithography and lithography processes, the lithography system may need to be maintained or replaced with other photomask components for exposure. At this point, step S6 can be performed, and the photomask assembly 200 (refer to FIG. 1 ) is removed from the lithography system. In view of the lithography process, the pellicle film may be damaged by high temperature, hydrogen gas, etc. to break bonds, resulting in stress and/or thickness changes. At this time, as in step S7 , optical detection and analysis may be performed on the photomask pellicle 220 (refer to FIG. 1 ) of the detached photomask assembly 200 . The optical detection and analysis in step S7 is roughly the same as that described in step S2 above, and will not be repeated here.

在步驟S8，根據該光學檢測分析的結果是否合格，決定進行步驟S9或S4’。 步驟S8的判斷/決定步驟大致如同前述步驟S3所述，在此不再贅述。當判斷該光學檢測分析的結果為不合格時，進行步驟S4’，棄置該不合格的光罩護膜220，並回到步驟S1。藉此，在下一次進行微影製程時，從存放區，取得另一個光罩護膜重新進行檢測。In step S8, according to whether the result of the optical detection analysis is qualified, it is decided to carry out step S9 or S4'. The judging/determining step in step S8 is roughly the same as that described in step S3 above, and will not be repeated here. When it is judged that the result of the optical detection analysis is unqualified, proceed to step S4', discard the unqualified photomask pellicle 220, and return to step S1. In this way, when the lithography process is performed next time, another photomask pellicle is obtained from the storage area for re-inspection.

當判斷該光學檢測分析的結果為合格時，進行步驟S9，將合格的該光罩護膜220，放置於暫存區。在下一次進行微影製程前，如步驟S10，可從暫存區，取出該光罩護膜220。When it is judged that the result of the optical inspection and analysis is qualified, step S9 is performed, and the qualified photomask pellicle 220 is placed in the temporary storage area. Before the next lithography process, as in step S10 , the photomask pellicle 220 may be taken out from the temporary storage area.

有鑑於光罩護膜220可能會隨著存放時間老化，因此，取出光罩護膜220後，可以接著進行步驟S2，再次進行光學檢測分析。若該光學檢測分析的結果為合格，可使用該合格的光罩護膜220安裝於光罩（如步驟S4）並進行微影製程（如步驟S5）。若該光學檢測分析的結果為不合格，進行步驟S4’，棄置該不合格的光罩護膜220，並回到步驟S1。藉此，在下一次進行微影製程時，從存放區，取得另一個光罩護膜重新進行檢測。Considering that the photomask pellicle 220 may age with storage time, after the photomask pellicle 220 is taken out, step S2 may be followed to perform optical detection and analysis again. If the result of the optical inspection and analysis is qualified, the qualified photomask pellicle 220 can be used to install on the photomask (such as step S4 ) and carry out the photolithography process (such as step S5 ). If the result of the optical detection analysis is unqualified, proceed to step S4', discard the unqualified photomask pellicle 220, and return to step S1. In this way, when the lithography process is performed next time, another photomask pellicle is obtained from the storage area for re-inspection.

於部分實施方式中，在進行步驟S7的光學檢測分析之前，可以先從光罩210上卸下光罩護膜220。藉此，可透過圖4A的檢測系統300的架構，以掃描平台410控制光罩護膜220的移動而進行掃描。其後，可以在進行步驟S2並經步驟S3判斷為合格後，如步驟S4重新將光罩護膜裝設於光罩上。In some implementations, before performing the optical detection and analysis in step S7 , the mask pellicle 220 may be removed from the mask 210 first. In this way, through the structure of the detection system 300 shown in FIG. 4A , the scanning platform 410 controls the movement of the pellicle 220 to perform scanning. Thereafter, after performing step S2 and judging as qualified by step S3, the photomask pellicle can be reinstalled on the photomask as in step S4.

於部份其他實施方式中，在進行步驟S7的光學檢測分析時，可以保持完整的光罩組件200（參考圖1）而不先從光罩210上卸下光罩護膜220。換句話說，步驟S7的光學檢測分析可以包含檢測完整的光罩組件200（參考圖1），例如將完整的光罩組件200（參考圖1）放置於掃描平台410（參考圖4A）。光罩210的反射性圖案212（參考圖1）可以反射穿過光罩護膜220的物件光線OL，進而可省略檢測系統300的物件反射鏡360（參考圖4A）。藉此，可透過圖4A的檢測系統300省去物件反射鏡360的架構，以掃描平台410控制光罩組件200（包含光罩210以及光罩護膜220）的移動而進行掃描。其後，將光罩組件200放置於暫存區（如步驟S9），從暫存區中取出光罩組件200（如步驟S10），並對此完整的光罩組件200進行光學檢測分析（如步驟S2）（例如將完整的光罩組件200（參考圖1）放置於掃描平台410（參考圖4A）），後續可省略步驟S4。In some other embodiments, when performing the optical detection and analysis in step S7 , the complete photomask assembly 200 (refer to FIG. 1 ) can be kept without removing the photomask pellicle 220 from the photomask 210 first. In other words, the optical inspection analysis in step S7 may include inspecting the complete mask assembly 200 (see FIG. 1 ), for example, placing the complete mask assembly 200 (see FIG. 1 ) on the scanning platform 410 (see FIG. 4A ). The reflective pattern 212 (refer to FIG. 1 ) of the reticle 210 can reflect the object light OL passing through the reticle pellicle 220 , so that the object reflector 360 (refer to FIG. 4A ) of the inspection system 300 can be omitted. Thereby, the detection system 300 in FIG. 4A can omit the structure of the object mirror 360 , and use the scanning platform 410 to control the movement of the photomask assembly 200 (including the photomask 210 and the photomask pellicle 220 ) for scanning. Thereafter, the photomask assembly 200 is placed in the temporary storage area (such as step S9), the photomask assembly 200 is taken out from the temporary storage area (such as step S10), and the complete photomask assembly 200 is optically detected and analyzed (such as Step S2 ) (for example, placing the complete mask assembly 200 (see FIG. 1 ) on the scanning platform 410 (see FIG. 4A )), step S4 may be omitted subsequently.

圖4A為根據本揭露部分實施方式的低同調光干涉檢測系統300的示意圖。低同調光干涉檢測系統300的基本架構為麥克森干涉儀（Michelson Interferometer），因使用低同調（寬頻）光作為光源，使得僅在參考臂和待測物臂的光程差短於同調長度的範圍內，才能夠量得干涉訊號，因此若同調長度越短（亦即光源頻寬越寬），得到組織深度方向的解析度就越佳。低同調光干涉檢測系統300可包含低同調（low-coherence）光源310、準直鏡（collimated lens）320、偏振片330、分光鏡340、物件聚焦鏡350、物件反射鏡360、參考聚焦鏡370、參考反射鏡380、聚光透鏡390、光譜儀感測器400、掃描平台410、鏡位置控制器MC、偏振態調整器PC以及處理器（例如電腦模組）420。FIG. 4A is a schematic diagram of a low-coherence optical interference detection system 300 according to some embodiments of the present disclosure. The basic structure of the low-coherence optical interference detection system 300 is Michelson Interferometer (Michelson Interferometer). Because low-coherence (broadband) light is used as the light source, only the optical path difference between the reference arm and the object arm is shorter than the coherence length The interference signal can only be measured within the range, so the shorter the coherence length (that is, the wider the bandwidth of the light source), the better the resolution in the tissue depth direction. The low-coherence optical interference detection system 300 may include a low-coherence light source 310, a collimated lens 320, a polarizer 330, a beam splitter 340, an object focusing mirror 350, an object reflecting mirror 360, and a reference focusing lens 370 , a reference mirror 380 , a condenser lens 390 , a spectrometer sensor 400 , a scanning platform 410 , a mirror position controller MC, a polarization state modifier PC, and a processor (such as a computer module) 420 .

於部分實施方式中，低同調光源310提供的光線可以具有較短的同調長度（coherence length），例如同調長度低於20微米、低於10微米、或甚至低於5微米。低同調光源310也可以稱為寬頻光源（broadband light source）。舉例而言，低同調光源310可為一白光光源，而低同調光干涉檢測系統300可為一白光干涉儀（WLI）。低同調光源310提供的光線可為無偏振的（unpolarized）。In some embodiments, the light provided by the low-coherence light source 310 may have a relatively short coherence length, for example, the coherence length is less than 20 microns, less than 10 microns, or even less than 5 microns. The low-coherence light source 310 may also be called a broadband light source. For example, the low coherence light source 310 can be a white light source, and the low coherence light interference detection system 300 can be a white light interferometer (WLI). The light provided by the low-coherence light source 310 may be unpolarized.

於部分實施方式中，準直鏡320用以接收來自寬頻光源310的光線，並將其轉成平行光。透過準直鏡320，可以模擬一無限遠的光源，以便於進行檢測。In some implementations, the collimating mirror 320 is used to receive the light from the broadband light source 310 and transform it into parallel light. Through the collimating mirror 320, an infinite light source can be simulated for easy detection.

於部分實施方式中，偏振片330用以控制光線的偏振態。舉例而言，偏振片330可以是線性偏振片、橢圓偏振片、圓形偏振片或其他適當的偏振片等。偏振片330可以連接至一偏振態調整器PC，以調整光的偏振方向。於部分實施方式中，透過偏振態調整器PC控制，可以使偏振片330在不同時點分別提供不同偏振態的光，例如偏振角度/方向不同的光。舉例而言，透過偏振態調整器PC控制，可以使偏振片330在不同時點分別提供偏振方向互相垂直的S偏振光以及P偏振光，或左旋圓偏振光以及右旋圓偏振光。於部分實施方式中，偏振片330以及偏振態調整器PC可合稱為偏振片組件。在部分實施例中，偏振態調整器PC可以旋轉偏振片330，從而改變偏振片330的線性偏振方向。或者，在部分實施例中，偏振片330可為一複合元件，包含一第一偏振區以及一第二偏振區，兩者對應不同的偏振片，偏振態調整器PC可以移動偏振片330而從第一第一偏振區移動至第二偏振區。或者，在部分實施例中，偏振態調整器PC可以連接至掃描平台410，以控制掃描平台410的角度，來實施不同的偏振態目的。In some implementations, the polarizer 330 is used to control the polarization state of the light. For example, the polarizer 330 may be a linear polarizer, an elliptical polarizer, a circular polarizer or other suitable polarizers. The polarizer 330 can be connected to a polarization adjuster PC to adjust the polarization direction of the light. In some implementations, through the control of the polarization state adjuster PC, the polarizer 330 can provide light with different polarization states at different time points, for example, light with different polarization angles/directions. For example, through the control of the polarization state adjuster PC, the polarizer 330 can respectively provide S-polarized light and P-polarized light whose polarization directions are perpendicular to each other, or left-handed circularly polarized light and right-handed circularly polarized light at different time points. In some implementations, the polarizer 330 and the polarization adjuster PC may be collectively referred to as a polarizer assembly. In some embodiments, the polarization state adjuster PC can rotate the polarizer 330 to change the linear polarization direction of the polarizer 330 . Alternatively, in some embodiments, the polarizer 330 can be a composite element, including a first polarization zone and a second polarization zone, both of which correspond to different polarizers, and the polarization state adjuster PC can move the polarizer 330 from The first first polarization zone moves to the second polarization zone. Alternatively, in some embodiments, the polarization adjuster PC can be connected to the scanning platform 410 to control the angle of the scanning platform 410 to implement different polarization purposes.

於部分實施方式中，分光鏡340用以將光分成物件光線（或稱為測試光線）OL以及參考光線RL，分別導向物件聚焦鏡350以及參考聚焦鏡370。於此，在一操作波長範圍（例如前述光源310提供的光線頻譜範圍）內，分光鏡340可被設計為偏振無關的且波長無關的。分光鏡340可依照特定反射/穿透比率分割光，同時保持入射光原始的偏振狀態以及光線頻譜。舉例而言，分光鏡340可以是50/50非偏振（non polarizing）分光鏡。In some implementations, the beam splitter 340 is used to split the light into an object ray (or called a test ray) OL and a reference ray RL, and guide them to the object focusing lens 350 and the reference focusing lens 370 respectively. Here, within an operating wavelength range (such as the light spectrum range provided by the aforementioned light source 310 ), the beam splitter 340 can be designed to be polarization-independent and wavelength-independent. The beam splitter 340 can split light according to a specific reflection/transmission ratio while maintaining the original polarization state and light spectrum of the incident light. For example, the beam splitter 340 may be a 50/50 non polarizing beam splitter.

於部分實施方式中，物件聚焦鏡350可將物件光線OL聚焦至光罩護膜220的局部。物件聚焦鏡350的焦距會對聚光點OLP的尺寸（focal spot size）造成影響，其中聚光點OLP的尺寸決定了低同調光干涉檢測系統300的解析度。換句話說，應力圖像的空間解析度可以由可用的聚光點OLP大小確定。於部分實施方式中，物件反射鏡360用以反射物件光線OL至分光鏡340。於部分實施方式中，參考聚焦鏡370可將參考光線RL聚焦。參考反射鏡380用以反射參考光線RL至分光鏡340。參考聚焦鏡370以及參考反射鏡380可分別具有與物件聚焦鏡350以及物件反射鏡360實質相同的光學特性，在此不再贅述。In some embodiments, the object focusing lens 350 can focus the object light OL to a part of the pellicle 220 . The focal length of the object focusing lens 350 affects the size of the focal spot OLP (focal spot size), wherein the size of the focal spot OLP determines the resolution of the low coherence optical interference detection system 300 . In other words, the spatial resolution of the stress image can be determined by the available spot OLP size. In some implementations, the object mirror 360 is used to reflect the object light OL to the beam splitter 340 . In some implementations, the reference focusing lens 370 can focus the reference light RL. The reference mirror 380 is used to reflect the reference light RL to the beam splitter 340 . The reference focusing mirror 370 and the reference mirror 380 may respectively have substantially the same optical characteristics as the object focusing mirror 350 and the object mirror 360 , which will not be repeated here.

當低同調光源310、準直鏡320、分光鏡340、物件聚焦鏡350、物件反射鏡360、參考聚焦鏡370、參考反射鏡380、聚光透鏡390以及光譜儀感測器400的位置擺放適當時，光源310的光線被分光鏡340分成兩個臂（例如物件光線OL以及參考光線RL），其中物件光線OL經光罩護膜220被物件反射鏡360，參考光線RL被參考反射鏡380反射。接著，可以將兩個干涉臂的反射光線（例如被物件反射鏡360反射且經光罩護膜220的物件光線OL以及被參考反射鏡380反射的參考光線RL）透過分光鏡340結合以及聚光透鏡390聚光，而在產生帶有干涉資訊的光波。光譜儀感測器400可收集帶有干涉資訊的光波並經由繞射得到其頻譜。When the positions of the low-coherent light source 310, collimating mirror 320, beam splitter 340, object focusing mirror 350, object reflecting mirror 360, reference focusing mirror 370, reference reflecting mirror 380, condenser lens 390 and spectrometer sensor 400 are properly placed , the light from the light source 310 is divided into two arms by the beam splitter 340 (such as the object ray OL and the reference ray RL), wherein the object ray OL passes through the mask film 220 and is reflected by the object reflector 360, and the reference ray RL is reflected by the reference reflector 380 . Then, the reflected light rays of the two interference arms (for example, the object light OL reflected by the object mirror 360 and passed through the mask pellicle 220 and the reference light RL reflected by the reference mirror 380 ) can be combined and concentrated by the beam splitter 340 The lens 390 concentrates light to generate light waves with interference information. The spectrometer sensor 400 can collect light waves with interference information and obtain their spectrum through diffraction.

於本揭露的部分實施方式中，參考反射鏡380可連接至鏡位置控制器MC。鏡位置控制器MC可以前後移動參考反射鏡380的位置，而改變參考干涉臂光線（例如參考光線RL）的光程，藉以掃描參考干涉臂光線的光程差。藉此，透過掃描參考干涉臂光線的光程差，並使用光譜儀感測器400以頻譜方式記錄一系列之光程差增量之每一者的干涉資訊（例如干涉圖案），可透過處理器420分析光譜儀感測器400的干涉資訊（例如干涉圖案）的變化，而得到光罩護膜220的群組延遲頻譜。於部分實施例中，此處理器420進行的訊號分析處理可包含：頻域分析（frequency domain analysis；FDA），將訊號轉換至頻域（frequency domain），隨著波長計算相位的改變率，而得到群組延遲頻譜（亦即各波長下的群組延遲）。或者，其他數值分析方式也可以適用。本揭露之多個實施方式中，以白光干涉系統為例，此群組延遲頻譜可例如為各白光波長下的群組延遲。In some embodiments of the present disclosure, reference mirror 380 may be connected to mirror position controller MC. The mirror position controller MC can move the position of the reference mirror 380 back and forth, so as to change the optical path of the reference interference arm light (for example, the reference light RL), so as to scan the optical path difference of the reference interference arm light. Thereby, by scanning the optical path difference of the reference interference arm light and using the spectrometer sensor 400 to spectrally record the interference information (such as the interference pattern) of each of a series of optical path difference increments, the processor can 420 analyzes the change of the interference information (such as the interference pattern) of the spectrometer sensor 400 to obtain the group delay spectrum of the pellicle 220 . In some embodiments, the signal analysis processing performed by the processor 420 may include: frequency domain analysis (frequency domain analysis; FDA), converting the signal to the frequency domain (frequency domain), calculating the change rate of the phase along with the wavelength, and Obtain the group delay spectrum (that is, the group delay at each wavelength). Alternatively, other numerical analysis methods may also be applicable. In multiple implementations of the present disclosure, taking a white light interference system as an example, the group delay spectrum can be, for example, the group delay at each white light wavelength.

於部分實施方式中，光譜儀感測器400可包含光柵以及陣列感測器（例如相機）。藉此，經頻譜分析（例如透過光柵取出各波長下的光強度），可以在掃描的一光程差下，得到圖4A中所示的頻譜（spectrum），即光強度對波長的關係圖。透過參考反射鏡380掃描多個光程差，可以得到多個頻譜圖，而構成時頻譜圖（spectrogram）。處理器420可以對該頻譜或該時頻譜圖進行訊號分析處理，以得到群組延遲頻譜。舉例而言，圖4A中，光譜儀感測器400中，光譜儀感測器400所示的頻譜的橫軸波長範圍在低同調光源310的發光頻譜範圍內，例如白光頻譜。In some embodiments, the spectrometer sensor 400 may include a grating and an array sensor (such as a camera). In this way, through spectral analysis (for example, taking out the light intensity at each wavelength through a grating), the spectrum shown in FIG. 4A can be obtained under a scanning optical path difference, that is, the relationship diagram of light intensity versus wavelength. By scanning multiple optical path differences through the reference mirror 380 , multiple spectrograms can be obtained to form a spectrogram. The processor 420 may perform signal analysis and processing on the frequency spectrum or the time spectrum diagram to obtain a group delay spectrum. For example, in FIG. 4A , in the spectrometer sensor 400 , the wavelength range on the horizontal axis of the spectrum shown by the spectrometer sensor 400 is within the emission spectrum range of the low-coherence light source 310 , such as the white light spectrum.

於部分實施方式中，因參考反射鏡380可受鏡位置控制器MC控制移動而達成掃描，參考反射鏡380又可稱為位置掃描反射鏡（position scan mirror）、光程差掃描平台、光程差掃描反射鏡等。In some implementations, because the reference mirror 380 can be moved by the mirror position controller MC to achieve scanning, the reference mirror 380 can also be called a position scan mirror, an optical path difference scanning platform, and an optical path difference scanning platform. Differential scanning mirrors, etc.

於本揭露的部分實施方式中，偏振態調整器PC可以調整偏振片330，進而改變光線的偏振態。藉此，透過偏振態調整器PC控制偏振片330，搭配前述的鏡位置控制器MC的光程差掃描，可以在各種不同的偏振態下進行前述的光程差掃描。具體而言，可以在各種不同的偏振態下，透過掃描參考干涉臂光線的光程差，並使用光譜儀感測器400以頻譜方式記錄一系列之光程差增量之每一者的干涉資訊（例如干涉圖案），透過處理器420分析光譜儀感測器400的干涉資訊（例如干涉圖案）的變化，而得到各種不同的偏振態下對應的群組延遲頻譜。In some embodiments of the present disclosure, the polarization adjuster PC can adjust the polarizer 330 to change the polarization state of the light. In this way, the polarizer 330 is controlled by the polarization adjuster PC, and the aforementioned optical path difference scanning can be performed in various polarization states in combination with the aforementioned optical path difference scanning of the mirror position controller MC. Specifically, the optical path difference of the reference interference arm light can be scanned under various polarization states, and the interference information of each of a series of optical path difference increments can be spectrally recorded using the spectrometer sensor 400 (such as interference pattern), the processor 420 analyzes the change of the interference information (such as the interference pattern) of the spectrometer sensor 400 to obtain the corresponding group delay spectrum under various polarization states.

於部分實施方式中，掃描平台410可以移動光罩護膜220，而掃描光罩護膜220的各個區域，進而獲得群組延遲頻譜的分布。同時參照圖4A以及圖4B。圖4B為根據本揭露部分實施方式的被檢測的光罩護膜的示意圖。藉由以掃描平台410移動光罩護膜220，而使物件光線OL的聚光點OLP依時序打在光罩護膜220的各個區域220R，而能夠量測得到光罩護膜220的多個區域220R的群組延遲頻譜。舉例而言，當光線沿Z方向入射光罩護膜220時，掃描平台410可以包含X-Y掃描平台，以便於在垂直光線入射的平面（即方向X與方向Y構成的平面）上調整光罩護膜220的位置。藉此，透過掃描平台410，可以使物件光線OL掃描光罩護膜220的各個區域220R。In some implementations, the scanning platform 410 can move the pellicle 220 to scan various regions of the pellicle 220 to obtain the distribution of the group delay spectrum. Refer to FIG. 4A and FIG. 4B at the same time. FIG. 4B is a schematic diagram of an inspected pellicle according to some embodiments of the present disclosure. By moving the photomask pellicle 220 with the scanning platform 410, the light spot OLP of the object light OL hits each region 220R of the photomask pellicle 220 in time sequence, and multiple parts of the photomask pellicle 220 can be measured. Group delay spectrum for region 220R. For example, when light is incident on the pellicle 220 along the Z direction, the scanning platform 410 may include an X-Y scanning platform, so as to adjust the pellicle on the plane perpendicular to the incident light (ie, the plane formed by the direction X and the direction Y). The location of the membrane 220 . Thereby, through the scanning platform 410 , the object light OL can be scanned to each region 220R of the pellicle 220 .

在部分實施方式中，處理器420可包含中央處理單元（Central Processing Unit；CPU）、多處理器、分散式處理系統、特殊應用積體電路（Application Specific Integrated Circuit ；ASIC）、或類似者。舉例而言，處理器420可以是電腦。處理器420可以連接上述鏡位置控制器MC、偏振態調整器PC、掃描平台410以及光譜儀感測器400。處理器420可連接或包含適當電子記憶體。處理器420可包含一或多個電子處理器，用以執行在電子記憶體中儲存的程式設計指令，此等程式設計指令可涉及控制鏡位置控制器MC、偏振態調整器PC以及掃描平台410的移動或調整的程式。處理器420還可包含一或多個電子處理器，用以執行在電子記憶體中儲存的程式，此等程式可涉及對光譜儀感測器400的光程差掃描的干涉資訊（例如干涉圖案）變化進行訊號分析處理，而獲得群組延遲頻譜。In some implementations, the processor 420 may include a central processing unit (Central Processing Unit; CPU), a multiprocessor, a distributed processing system, an application specific integrated circuit (Application Specific Integrated Circuit; ASIC), or the like. For example, the processor 420 can be a computer. The processor 420 can be connected to the mirror position controller MC, the polarization state modifier PC, the scanning platform 410 and the spectrometer sensor 400 mentioned above. Processor 420 may be connected to or contain appropriate electronic memory. Processor 420 may include one or more electronic processors for executing programmed instructions stored in electronic memory that may be involved in controlling mirror position controller MC, polarization modifier PC, and scanning platform 410 program of movement or adjustment. Processor 420 may also include one or more electronic processors for executing programs stored in electronic memory that may involve interference information (e.g., interference patterns) for optical path difference scans of spectrometer sensor 400 Changes are analyzed and processed to obtain a group delay spectrum.

圖5A為本揭露部分實施方式的檢測方法的光學檢測分析的實施方塊圖。圖3的步驟S2以及/或S7可包含光學檢測分析AS。光學檢測分析AS可包含步驟AS1、步驟AS2、步驟AS3之至少一者或其組合。應了解到，可以在步驟AS1~AS3之前、之中以及之後加入額外的步驟，且對於該方法的另一部份實施方式，以下提到的部分步驟可以被取代或取消。步驟/程序的順序可以被改變。FIG. 5A is a block diagram of the implementation of the optical detection analysis of the detection method according to some embodiments of the present disclosure. Steps S2 and/or S7 of FIG. 3 may include optical detection analysis AS. Optical detection analysis AS may include at least one of step AS1, step AS2, step AS3 or a combination thereof. It should be understood that additional steps can be added before, during and after steps AS1-AS3, and for another partial implementation of the method, some of the steps mentioned below can be replaced or eliminated. The order of steps/procedures can be changed.

在步驟AS1中，以低同調光干涉檢測系統300，掃描各個區域，計算各個區域的偏振態色散資訊差（例如不同偏振態的群組延遲頻譜的差），而構成光罩護膜220的偏振態色散資訊差的分布。後續的圖3的判斷步驟S3以及/或S8，可基於此振態資訊差的分布而進行。圖5B為圖5A的光學檢測分析AS的步驟AS1的一實施方式的一流程圖。同時參照圖5A以及圖5B，具體而言，步驟AS1可包含複數個重複循環，每一循環包含對光罩護膜220的一個區域進行步驟AS12至AS16。藉此，重複這些循環，可掃描整個光罩護膜220。In step AS1, the low-coherence optical interference detection system 300 is used to scan each area, and the polarization state dispersion information difference of each area (such as the difference of the group delay spectrum of different polarization states) is calculated to form the polarization of the mask protective film 220 The distribution of state dispersion information difference. The subsequent determining steps S3 and/or S8 in FIG. 3 may be performed based on the distribution of the vibration state information difference. FIG. 5B is a flowchart of an embodiment of step AS1 of the optical detection analysis AS of FIG. 5A . Referring to FIG. 5A and FIG. 5B at the same time, specifically, step AS1 may include a plurality of repeated cycles, and each cycle includes performing steps AS12 to AS16 on a region of the pellicle 220 . By repeating these cycles, the entire pellicle 220 can be scanned.

在步驟AS12中，以一第一偏振光，透過低同調光干涉系統量測光罩護膜的一區域，獲得第一偏振態色散資訊（例如第一偏振態群組延遲頻譜）。在步驟AS14中，以一第二偏振態，透過低同調光干涉系統量測光罩護膜的該區域， 獲得第二偏振態色散資訊（例如第二偏振態群組延遲頻譜）。In step AS12 , a first polarized light is used to measure a region of the mask pellicle through a low-coherence optical interference system to obtain first polarization state dispersion information (such as a first polarization state group delay spectrum). In step AS14 , the region of the mask pellicle is measured through a low-coherence optical interference system with a second polarization state to obtain second polarization state dispersion information (eg, second polarization state group delay spectrum).

舉例而言，參考圖6A以及圖6B。圖6A以及圖6B分別繪示根據本揭露部分實施方式使用S偏振光以及P偏振光量測的光罩護膜220的群組延遲頻譜圖。在圖6A以及圖6B中，縱軸為群組延遲，橫軸為波長。具體而言，當圖4A的低同調光干涉檢測系統300的偏振片330（例如受到偏振態調整器PC控制為S偏振狀態）是為S偏振片時，物件光線OL以及參考光線RL為S偏振光，可以由鏡位置控制器MC進行掃描、光譜儀感測器400獲得干涉資訊（例如干涉圖案）變化、再透過處理器420分析，而得到圖6A。當圖4A的低同調光干涉檢測系統300的偏振片330（例如受到偏振態調整器PC控制為P偏振狀態）是為P偏振片時，物件光線OL以及參考光線RL為P偏振光，可以由鏡位置控制器MC進行掃描、光譜儀感測器400獲得干涉資訊（例如干涉圖案）變化、再透過處理器420分析，而得到圖6B。局部應力會引起雙折射，因此S 和 P 偏振光會觀察到不同的折射率，從而產生不同的光程。For example, refer to FIG. 6A and FIG. 6B. FIG. 6A and FIG. 6B respectively illustrate group retardation spectrum diagrams of the photomask pellicle 220 measured using S-polarized light and P-polarized light according to some embodiments of the present disclosure. In FIG. 6A and FIG. 6B , the vertical axis represents the group delay, and the horizontal axis represents the wavelength. Specifically, when the polarizer 330 of the low-coherence optical interference detection system 300 in FIG. 4A (for example, controlled by the polarization state adjuster PC to be in the S polarization state) is an S polarizer, the object ray OL and the reference ray RL are S polarized The light can be scanned by the mirror position controller MC, the spectrometer sensor 400 obtains the change of interference information (such as the interference pattern), and then is analyzed by the processor 420 to obtain FIG. 6A . When the polarizer 330 of the low-coherence optical interference detection system 300 in FIG. 4A (for example, controlled by the polarization state adjuster PC to be in the P polarization state) is a P polarizer, the object light OL and the reference light RL are P polarized light, which can be obtained by The mirror position controller MC scans, and the spectrometer sensor 400 obtains changes in interference information (such as interference patterns), which are then analyzed by the processor 420 to obtain FIG. 6B . Localized stress induces birefringence so that S and P polarized light observe different refractive indices and thus different optical path lengths.

接著，在步驟AS16中，將第一偏振態色散資訊（例如第一偏振態群組延遲頻譜）與第二偏振態色散資訊（例如第二偏振態群組延遲頻譜）相減，而獲得該區域的偏振態色散資訊差（例如群組延遲頻譜的差）。舉例而言，在獲得S偏振光以及P偏振光量測的群組延遲頻譜圖（例如圖6A以及圖6B）後，可以透過將兩者相減而推估光罩護膜的折射率各向異性（或雙折射性），從而評估光罩護膜每個區域的應力拉伸情況。可參考以下數學式。 [數學式1] [數學式2] Next, in step AS16, the first polarization state dispersion information (such as the first polarization state group delay spectrum) is subtracted from the second polarization state dispersion information (such as the second polarization state group delay spectrum) to obtain the region The polarization state dispersion information difference (such as the difference in the group delay spectrum) of . For example, after obtaining the group retardation spectrograms measured by S-polarized light and P-polarized light (such as Figure 6A and Figure 6B), the refractive index anisotropy of the pellicle can be estimated by subtracting the two Anisotropy (or birefringence) to assess stress stretch in each area of the reticle pellicle. The following mathematical formula can be referred to. [mathematical formula 1] [mathematical formula 2]

其中 為波長， 為S偏振光所見的光罩護膜折射率。 為P偏振光所見的光罩護膜折射率。 為 以及 兩折射率的差值，可表示光罩護膜的折射率各向異性(或雙折射性)。Z f為光罩護膜厚度。 為S偏振光與P偏振光的光程差（optical path difference）。 為S偏振光通過光罩護膜的群組延遲頻譜，例如圖6A。 為P偏振光通過光罩護膜的群組延遲頻譜，例如圖6B。 為S偏振光與P偏振光的群組延遲頻譜的差（group delay difference）。c為真空中的光速。根據以上公式，可知 正比於 。據此，光罩護膜各區域的群組延遲頻譜的差（即 ）關係可以推知光罩護膜各區域的折射率各向異性（或雙折射性，例如 ）關係，繼而評估光罩護膜各區域的應力拉伸情況。可參考以下圖7A至圖7C。 in is the wavelength, Refractive index of the reticle pellicle as seen for S-polarized light. Refractive index of the reticle pellicle as seen by P-polarized light. for as well as The difference between the two refractive indices can represent the refractive index anisotropy (or birefringence) of the pellicle. Z f is the thickness of the mask film. is the optical path difference between S polarized light and P polarized light. is the group delay spectrum of S-polarized light passing through the pellicle, as shown in Figure 6A. is the group delay spectrum of P-polarized light passing through the pellicle, as shown in FIG. 6B . is the group delay spectrum difference between S-polarized light and P-polarized light (group delay difference). c is the speed of light in vacuum. According to the above formula, it can be seen that Proportional to . Accordingly, the difference in the group delay spectrum of each region of the mask pellicle (i.e. ) relationship can infer the refractive index anisotropy (or birefringence) of each region of the mask pellicle, such as ) relationship, and then evaluate the stress stretch in each region of the mask pellicle. Reference may be made to FIGS. 7A to 7C below.

圖7A繪示根據本揭露部分實施方式的一第一薄膜的群組延遲頻譜的差（即 ）。圖7A為群組延遲差的頻譜圖，其中縱軸為群組延遲差，橫軸為波長。在本實施方式中，第一薄膜的材料為熔融石英。透過前述的低同調光干涉檢測系統300，可以獲得此熔融石英的S偏振群組延遲頻譜以及P偏振群組延遲頻譜，兩者相減而得到圖7A。從圖7A可發現，熔融石英的群組延遲差在各波長下大致維持不變。舉例而言，群組延遲頻譜差的幅度（magnitude）D A大約為0。這表示，在熔融石英中，折射率以及/或應力是實質上各向同性的。S偏振光以及P偏振光之間，幾乎沒有群組延遲頻譜差（即 ）。 FIG. 7A shows the difference in the group delay spectrum of a first thin film according to some embodiments of the present disclosure (ie ). FIG. 7A is a spectrum diagram of the group delay difference, wherein the vertical axis is the group delay difference, and the horizontal axis is the wavelength. In this embodiment, the material of the first thin film is fused silica. Through the aforementioned low-coherent optical interference detection system 300, the S-polarized group delay spectrum and the P-polarized group delay spectrum of the fused silica can be obtained, and the two are subtracted to obtain FIG. 7A. From FIG. 7A , it can be found that the group retardation difference of fused silica remains almost constant at each wavelength. For example, the magnitude D A of the group delay spectrum difference is approximately zero. This means that in fused silica, the refractive index and/or stress is substantially isotropic. There is almost no group delay spectrum difference between S-polarized light and P-polarized light (ie ).

圖7B繪示根據本揭露部分實施方式的未經拉伸的第二薄膜的群組延遲頻譜的差（即 ）。圖7B為群組延遲差的頻譜圖，其中縱軸為群組延遲差，橫軸為波長。在本實施方式中，第二薄膜的材料為聚醯亞胺（PI）薄膜。透過前述的低同調光干涉檢測系統300，可以獲得未經拉伸的PI薄膜的S偏振群組延遲頻譜以及P偏振群組延遲頻譜，兩者相減而得到圖7B。從圖7B可發現，S偏振光以及P偏振光之間存在群組延遲頻譜差（即 ），尤其藍光更為敏感。舉例而言，群組延遲頻譜差的幅度D B在大約2 fs至4 fs的範圍內。這表示，在未經拉伸的PI薄膜中，折射率以及/或應力是各向異性性的。 FIG. 7B shows the difference in the group retardation spectrum of the unstretched second film according to some embodiments of the present disclosure (ie ). FIG. 7B is a spectrum diagram of the group delay difference, wherein the vertical axis is the group delay difference, and the horizontal axis is the wavelength. In this embodiment, the material of the second film is polyimide (PI) film. Through the aforementioned low-coherent optical interference detection system 300 , the S-polarized group delay spectrum and the P-polarized group delay spectrum of the unstretched PI film can be obtained, and the two are subtracted to obtain FIG. 7B . It can be found from Figure 7B that there is a group delay spectrum difference between S-polarized light and P-polarized light (ie ), especially blue light is more sensitive. For example, the magnitude D B of the group delay spectral difference is in the range of about 2 fs to 4 fs. This means that in unstretched PI films, the refractive index and/or stress is anisotropic.

圖7C示根據本揭露部分實施方式的經拉伸的第二薄膜的群組延遲頻譜的差（即 ）。圖7C為群組延遲差的頻譜圖，其中縱軸為群組延遲差，橫軸為波長。透過前述的低同調光干涉檢測系統300，可以獲得經拉伸的PI薄膜的S偏振群組延遲頻譜以及P偏振群組延遲頻譜，兩者相減而得到圖7C。從圖7C可發現，S偏振光以及P偏振光之間存在群組延遲頻譜差（即 ）。舉例而言，群組延遲頻譜差的幅度D C在大約4 fs至7 fs的範圍內。這表示，在經拉伸的PI薄膜中，折射率以及/或應力是各向異性的。比較圖7B與圖7C，可以發現，圖7C的群組延遲頻譜差的幅度D C更大。這表示，拉伸作用提升了PI薄膜的折射率以及/或應力的各向異性。 7C shows the difference in the group retardation spectrum of the stretched second film according to some embodiments of the present disclosure (i.e. ). FIG. 7C is a spectrum diagram of the group delay difference, wherein the vertical axis is the group delay difference, and the horizontal axis is the wavelength. Through the aforementioned low-coherence optical interference detection system 300, the S-polarization group delay spectrum and the P-polarization group delay spectrum of the stretched PI film can be obtained, and the two are subtracted to obtain FIG. 7C. It can be found from Figure 7C that there is a group delay spectrum difference between S-polarized light and P-polarized light (ie ). For example, the magnitude D C of the group delay spectral difference is in the range of about 4 fs to 7 fs. This means that in stretched PI films, the refractive index and/or stress is anisotropic. Comparing FIG. 7B and FIG. 7C , it can be found that the magnitude D C of the group delay spectrum difference in FIG. 7C is larger. This means that the stretching effect increases the refractive index and/or stress anisotropy of the PI film.

再回到圖6A，透過步驟AS1，並取出各個區域的群組延遲差的幅度，可以獲得圖8A。圖8A中，縱軸為群組延遲差的幅度，橫軸為光罩護膜位置。圖中標示群組延遲差的幅度的平均值μ D、其上限UB D以及下限LB D。上限UB D以及下限LB D可分別為平均值μ D加減一預定比例，例如5%至100%的範圍。如前所述，在光學分析後的步驟S3或S8中，可判斷每一該些區域的該偏振態色散資訊差是否不位於上限UB D至LB D的範圍內，若一部分的該些區域是的話，則判斷該部分的該些區域為異常；以及當異常的該部分的該些區域的數量小於該些區域的總數量的一預定比例（例如大約2%至大約60%），判斷該光罩護膜為合格。在圖8A中，偏振態色散資訊僅以群組延遲頻譜的差的幅度為例，來辨別應力均勻與否，但不應以此為限制。於其他實施方式中，可以從群組延遲頻譜中取出其他參數（例如群組延遲頻譜的差的幅度的梯度（即幅度對位置微分）、群組延遲色散（即群組延遲頻譜對角頻率微分）、護膜厚度等）作為評估的標準，而不以幅度為限。 Going back to FIG. 6A , through step AS1 and taking out the magnitude of the group delay difference of each area, FIG. 8A can be obtained. In FIG. 8A , the vertical axis is the magnitude of the group retardation difference, and the horizontal axis is the position of the pellicle. The figure indicates the average value μ D , the upper limit UB D and the lower limit LB D of the magnitude of the group delay difference. The upper limit UB D and the lower limit LB D may respectively be the average value μ D plus or minus a predetermined ratio, such as a range of 5% to 100%. As mentioned above, in step S3 or S8 after the optical analysis, it can be judged whether the polarization state dispersion information difference of each of these areas is not within the range of the upper limit UB D to LB D , if a part of these areas are , then judge that the areas of the part are abnormal; The cover film is qualified. In FIG. 8A , the polarization state dispersion information is only used as an example to identify whether the stress is uniform or not by using the magnitude of the group delay spectrum difference, but this should not be limited. In other implementations, other parameters (such as the gradient of the magnitude of the difference between the group delay spectrum (ie, the differential of the amplitude to the position), the group delay dispersion (ie, the differential of the diagonal frequency of the group delay spectrum) can be taken out from the group delay spectrum. ), film thickness, etc.) as the evaluation standard, not limited to the range.

在步驟AS2中，在掃描完光罩護膜220的各個區域後，計算各個區域的護膜厚度，而獲得護膜厚度分佈。後續的圖3的檢測方法M的判斷步驟S3以及/或S8，可基於此護膜厚度的分布而進行。具體而言，透過低同調光干涉系統量測光罩護膜的一區域，以非偏振光（或第一偏振以及第二偏振光的組合），獲得一群組延遲頻譜。於部分實施例中，此群組延遲頻譜可相當於將前述的第一偏振態群組延遲頻譜以及第二偏振態群組延遲頻譜加總。其後，將此群組延遲頻譜與光罩護膜的一平均色散折射率（即 ）映射（mapping），以獲得該區域的一厚度資訊。舉例而言，將前述的第一偏振態群組延遲頻譜以及第二偏振態群組延遲頻譜加總後，再除以該平均色散折射率，以得到該厚度資訊。上述該厚度資訊正比於薄膜厚度（即Z f）。於部分實施方式中，可以將可加總後的數值選擇性地除以二，以得到該薄膜厚度（即Z f）。平均色散折射率可以從數據表（data sheet）或透過其他量測系統量測光罩護膜而獲得。藉此，可獲得光罩護膜220的厚度差分佈。舉例而言，透過步驟AS2，可以獲得圖8B。 In step AS2 , after scanning each region of the pellicle 220 , the pellicle thickness of each region is calculated to obtain the pellicle thickness distribution. Subsequent determination steps S3 and/or S8 of the detection method M in FIG. 3 may be performed based on the distribution of the coating thickness. Specifically, a region of the mask pellicle is measured through a low-coherence optical interference system, and a group delay spectrum is obtained with unpolarized light (or a combination of the first polarized light and the second polarized light). In some embodiments, the group delay spectrum may be equivalent to the sum of the aforementioned group delay spectrum of the first polarization state and the group delay spectrum of the second polarization state. Then, the group retardation spectrum is compared with an average dispersion refractive index of the mask pellicle (ie ) mapping (mapping) to obtain a thickness information of the region. For example, the aforementioned group delay spectrum of the first polarization state and the group delay spectrum of the second polarization state are summed up, and then divided by the average dispersion refractive index to obtain the thickness information. The above thickness information is proportional to the film thickness (ie Z f ). In some embodiments, the summable values can optionally be divided by two to obtain the film thickness (ie Z f ). The average dispersion index can be obtained from the data sheet or by measuring the pellicle of the reticle through other measurement systems. Thereby, the thickness difference distribution of the pellicle 220 can be obtained. For example, through step AS2, FIG. 8B can be obtained.

圖8B中，縱軸為厚度，橫軸為光罩護膜位置。圖中標示厚度的平均值μ T、其上限UB T以及下限LB T。上限UB T以及下限LB T可分別為平均值μ T加減一預定比例，例如5%至100%的範圍。如前所述，在光學分析後的步驟S3或S8中，可判斷每一該些區域的該偏振態色散資訊差是否不位於上限UB T至LB T的範圍內，若一部分的該些區域是的話，則判斷該部分的該些區域為異常；以及當異常的該部分的該些區域的數量小於該些區域的總數量的一預定比例（例如大約2%至大約60%），判斷該光罩護膜為合格。 In FIG. 8B , the vertical axis is the thickness, and the horizontal axis is the position of the pellicle. The average thickness μ T , the upper limit UB T and the lower limit LB T of the thickness are indicated in the figure. The upper limit UB T and the lower limit LB T may respectively be the average value μ T plus or minus a predetermined ratio, such as a range from 5% to 100%. As mentioned above, in the step S3 or S8 after the optical analysis, it can be judged whether the polarization state dispersion information difference of each of these regions is not within the range of the upper limit UB T to LB T , if a part of these regions are , then judge that the areas of the part are abnormal; The cover film is qualified.

在步驟AS3中，以護膜厚度校正偏振態色散資訊差，而獲得經校正的偏振態色散資訊差分佈。於此，可以將前述各個區域的群組延遲差（即 ）（參照圖7A至圖7C）或其幅度（參照圖8A）除上各區域的厚度資訊（參照圖8B）。此舉可以校正光罩護膜220各區域的折射率各向異性關係，以直接反映了局部應力的各向異性，進而提升檢測的準確度。舉例而言，透過步驟AS3，可以獲得圖8C。 In step AS3, the polarization state dispersion information difference is corrected by the film thickness to obtain the corrected polarization state dispersion information difference distribution. Here, the group delay difference of the aforementioned areas (ie ) (refer to FIG. 7A to FIG. 7C ) or its amplitude (refer to FIG. 8A ) and divide the thickness information of each region (refer to FIG. 8B ). This can correct the anisotropy relationship of the refractive index in each region of the mask pellicle 220 to directly reflect the anisotropy of the local stress, thereby improving the detection accuracy. For example, through step AS3, FIG. 8C can be obtained.

圖8C中，縱軸為經校正的群組延遲差的幅度，橫軸為光罩護膜位置。圖中標示經校正的群組延遲差的幅度的平均值μ DC、其上限UB DC以及下限LB DC。上限UB D以及下限LB DC可分別為平均值μ DC加減一預定比例，例如5%至100%的範圍。如前所述，在光學分析後的步驟S3或S8中，可判斷每一該些區域的該偏振態色散資訊差是否不位於上限UB DC至LB DC的範圍內，若一部分的該些區域是的話，則判斷該部分的該些區域為異常；以及當異常的該部分的該些區域的數量小於該些區域的總數量的一預定比例（例如大約2%至大約60%），判斷該光罩護膜為合格。在圖8C中，偏振態色散資訊以經校正的群組延遲頻譜的差的幅度為例，來辨別應力均勻與否，但不應以此為限制。於其他實施方式中，可以從經校正的群組延遲頻譜中取出其他參數（例如經校正的群組延遲頻譜的差的該幅度的梯度（即經校正的幅度對位置微分）、經校正的群組延遲色散（即經校正的群組延遲頻譜對角頻率微分））作為評估的標準，而不以幅度為限。 In FIG. 8C , the vertical axis is the magnitude of the corrected group delay difference, and the horizontal axis is the position of the pellicle. The figure indicates the average value μ DC , the upper limit UB DC and the lower limit LB DC of the magnitude of the corrected group delay difference. The upper limit UB D and the lower limit LB DC may respectively be the average value μ DC plus or minus a predetermined ratio, such as a range of 5% to 100%. As mentioned above, in the step S3 or S8 after the optical analysis, it can be judged whether the polarization state dispersion information difference of each of these regions is not in the range of the upper limit UB DC to LB DC , if some of these regions are , then judge that the areas of the part are abnormal; The cover film is qualified. In FIG. 8C , the polarization state dispersion information uses the magnitude of the difference of the corrected group delay spectrum as an example to identify whether the stress is uniform or not, but this should not be limited. In other embodiments, other parameters can be extracted from the corrected group delay spectrum (such as the gradient of the magnitude of the difference of the corrected group delay spectrum (i.e. the corrected amplitude vs. position differential), the corrected group delay Group delay dispersion (i.e., the diagonal frequency differential of the corrected group delay spectrum)) is used as a criterion for evaluation, not limited to magnitude.

於部份實施方式中，以上校正步驟AS3可以省略，步驟AS1可以獨立的執行，而不需考慮薄膜厚度（即Z f）。換句話說，在部分實施方式中，光罩護膜各區域的厚度（即Z f）可以視為均勻，而不以厚度校正光罩護膜220各區域的折射率各向異性關係。 In some embodiments, the above calibration step AS3 can be omitted, and step AS1 can be performed independently without considering the film thickness (ie Z f ). In other words, in some embodiments, the thickness (ie, Z f ) of each region of the pellicle film can be regarded as uniform, and the refractive index anisotropy relationship of each region of the pellicle film 220 is not corrected by the thickness.

於本揭露的部分實施方式中，透過偏振片330，可以量測光罩護膜220在各種偏振態下的群組延遲頻譜，由各種偏振態的群組延遲頻譜，可推知光罩護膜220的在不同入射偏振下的色散特性（例如各向異性折射率變化），進而推測光罩護膜220的應力分布。此外，可以也可以透過映射（mapping），從非偏振光的群組延遲頻譜與平均色散折射率曲線中，獲得光罩護膜220，以進一步校正各種偏振態的群組延遲頻譜，提升估計應力分布的精準度。In some embodiments of the present disclosure, the group delay spectrum of the pellicle 220 under various polarization states can be measured through the polarizer 330, and the group delay spectrum of the pellicle 220 can be deduced from the group delay spectra of various polarization states. The dispersion characteristics (such as anisotropic refractive index change) under different incident polarizations are used to estimate the stress distribution of the pellicle 220 . In addition, the mask pellicle 220 can be obtained from the group delay spectrum of unpolarized light and the average dispersion refractive index curve through mapping, so as to further correct the group delay spectrum of various polarization states and improve the estimated stress The precision of the distribution.

基於以上討論，可以看出本揭露提供了的多個優點。然而，應該理解，其他實施方式可以提供額外的優點，並且並非所有優點都必須在此公開，並且並非所有實施方式都需要特定優點。本案的優點之一是可以在光罩護膜上線之前（例如從存放區取出至安裝至光罩之間），透過低同調干涉技術離線地（off-line）檢測光罩護膜雙折射性，以及早判斷光罩護膜的應力狀況，避免後續在機台內部破裂而衍伸的問題。本案的優點之另一優點是為非接觸式（non-contact）光學檢測，不會對光罩護膜造成汙染。本案的再一優點是使用低能量的低同調光（例如白光）照射光罩護膜來表現其色散特性，而不會侵害光罩護膜。本案的又一優點是可以在任何氣壓條件的環境下進行，不限於真空環境。Based on the above discussion, it can be seen that the present disclosure provides several advantages. It should be understood, however, that other embodiments may provide additional advantages, and that not all advantages must necessarily be disclosed herein, and that not all embodiments require a particular advantage. One of the advantages of this case is that the birefringence of the mask pellicle can be detected offline (off-line) through low-coherence interferometry before the pellicle is put on the line (for example, when it is taken out from the storage area and installed on the mask). Early judgment of the stress state of the photomask pellicle avoids the problem of subsequent rupture and extension inside the machine. Another advantage of this case is that it is a non-contact optical inspection, which will not pollute the pellicle of the photomask. Another advantage of this case is to use low-energy low-coherent light (such as white light) to irradiate the pellicle to express its dispersion characteristics without damaging the pellicle. Another advantage of this case is that it can be carried out in any atmospheric pressure environment, not limited to vacuum environment.

根據本揭露的部分實施方式中，光罩護膜檢測方法包含以一低同調光干涉系統，分別使用一第一偏振光以及一第二偏振光，量測一光罩護膜的複數個區域，以分別獲得每一該些區域的一第一偏振態色散資訊以及一第二偏振態色散資訊，其中該第一偏振光的偏振態不同於該第二偏振光的偏振態；計算每一該些區域的該第一偏振態色散資訊以及該第二偏振態色散資訊，以判斷該光罩護膜是否合格；以及將合格的該光罩護膜裝設至一光罩上。According to some embodiments of the present disclosure, the method for inspecting a pellicle includes measuring a plurality of regions of a pellicle by using a low-coherence optical interference system, respectively using a first polarized light and a second polarized light, To respectively obtain a first polarization state dispersion information and a second polarization state dispersion information of each of the regions, wherein the polarization state of the first polarized light is different from the polarization state of the second polarized light; calculate each of the The first polarization state dispersion information and the second polarization state dispersion information of the area to judge whether the mask pellicle is qualified; and install the qualified mask pellicle on a photomask.

根據本揭露的部分實施方式中，光罩護膜檢測方法包含以一低同調光干涉系統，量測一光罩護膜的複數個區域，以獲得每一該些區域的一群組延遲頻譜；計算每一該些區域的該群組延遲頻譜，以判斷該光罩護膜是否合格；以及將合格的該光罩護膜裝設至一光罩上。According to some embodiments of the present disclosure, the pellicle detection method includes measuring a plurality of regions of a pellicle with a low-coherence optical interferometry system to obtain a group delay spectrum of each of the regions; calculating the group delay spectrum of each of the regions to judge whether the photomask pellicle is qualified; and installing the qualified photomask pellicle on a photomask.

根據本揭露的部分實施方式中，光罩護膜檢測系統包含白光光源、複數個干涉儀光學組件、參考掃描台、光譜儀感測器、偏振片組件以及處理器。干涉儀光學組件用以結合一物件光以及一參考光，其中該物件光以及該參考光來自該白光光源。參考掃描台用以掃描該物件光以及該參考光之間的一光程差。光譜儀感測器用以紀錄一系列之光程差增量之每一者的干涉資訊。偏振片組件用以控制該物件光以及該參考光係為一第一偏振態或一第二偏振態。處理器電性連接該光譜儀感測器、該光程差掃描平台以及該偏振片組件。該處理器用以：使該物件光以及該參考光係為一第一偏振態，取得一第一干涉資訊；使該物件光以及該參考光係為一第二偏振態，取得一第二干涉資訊；分析該第一干涉資訊以及該第二干涉資訊，以分別獲得一第一偏振態色散資訊以及一第二偏振態色散資訊；以及計算該第一偏振態色散資訊以及該第二偏振態色散資訊，以判斷該光罩護膜是否合格。According to some embodiments of the present disclosure, a pellicle inspection system includes a white light source, a plurality of interferometer optical components, a reference scanning stage, a spectrometer sensor, a polarizer component, and a processor. The interferometer optical component is used for combining an object light and a reference light, wherein the object light and the reference light come from the white light source. The reference scanning stage is used for scanning an optical path difference between the object light and the reference light. A spectrometer sensor is used to record interference information for each of a series of optical path difference increments. The polarizer assembly is used to control the object light and the reference light to be a first polarization state or a second polarization state. The processor is electrically connected to the spectrometer sensor, the optical path difference scanning platform and the polarizer assembly. The processor is used for: making the object light and the reference light be in a first polarization state to obtain a first interference information; making the object light and the reference light be in a second polarization state to obtain a second interference information ; analyzing the first interference information and the second interference information to obtain a first polarization state dispersion information and a second polarization state dispersion information respectively; and calculating the first polarization state dispersion information and the second polarization state dispersion information , to judge whether the pellicle is qualified.

以上概述多個實施方式之特徵，該技術領域具有通常知識者可較佳地了解本揭露之多個態樣。該技術領域具有通常知識者應了解，可將本揭露作為設計或修飾其他製程或結構的基礎，以實行實施方式中提到的相同的目的以及/或達到相同的好處。該技術領域具有通常知識者也應了解，這些相等的結構並未超出本揭露之精神與範圍，且可以進行各種改變、替換、轉化，在此，本揭露精神與範圍涵蓋這些改變、替換、轉化。The features of several embodiments are summarized above, and those skilled in the art can better understand the various aspects of the present disclosure. Those skilled in the art should understand that this disclosure can be used as a basis for designing or modifying other processes or structures, so as to achieve the same purpose and/or achieve the same benefits mentioned in the embodiments. Those with ordinary knowledge in this technical field should also understand that these equivalent structures do not exceed the spirit and scope of the present disclosure, and can undergo various changes, substitutions, and transformations. Here, the spirit and scope of this disclosure cover these changes, substitutions, and transformations .

100:微影系統 110:輻射源 120:照射器 130:光罩台 140:投影光學模組 150:基板台 200:光罩組件 210:光罩 212:反射性圖案 220:光罩護膜 220R:區域 222:粒子 224:鍵結 230:框架 300:檢測系統 310:光源 320:準直鏡 330:偏振片 340:分光鏡 350:物件聚焦鏡 360:物件反射鏡 370:參考聚焦鏡 380:參考反射鏡 390:聚光透鏡 400:光譜儀感測器 410:掃描平台 420:處理器 W:半導體基板 X:方向 Y:方向 Z:方向 L p:第一偏振光 L s:第二偏振光 M:檢測方法 S1~S10:步驟 MC:鏡位置控制器 PC:偏振態調整器 OL:物件光線 OLP:聚光點 RL:參考光線 AS:光學檢測分析 AS1, AS2, AS3:步驟 AS12, AS14, AS16:步驟 μ D, μ T, μ DC:平均值 UB D, UB T, UB DC:上限 LB D, LB T, LB DC:下限 100: Lithography system 110: Radiation source 120: Irradiator 130: Mask table 140: Projection optical module 150: Substrate table 200: Mask assembly 210: Mask 212: Reflective pattern 220: Mask protective film 220R: Area 222: Particles 224: Bonding 230: Frame 300: Detection System 310: Light Source 320: Collimating Mirror 330: Polarizer 340: Beam Splitter 350: Object Focusing Mirror 360: Object Mirror 370: Reference Focusing Mirror 380: Reference Reflection Mirror 390: condenser lens 400: spectrometer sensor 410: scanning platform 420: processor W: semiconductor substrate X: direction Y: direction Z: direction Lp : first polarized light Ls : second polarized light M: detection Methods S1~S10: Steps MC: Mirror Position Controller PC: Polarization Adjuster OL: Object Light OLP: Focus Point RL: Reference Light AS: Optical Detection and Analysis AS1, AS2, AS3: Steps AS12, AS14, AS16: Steps μ D , μ T , μ DC : average value UB D , UB T , UB DC : upper limit LB D , LB T , LB DC : lower limit

當結合隨附圖式閱讀時，根據以下詳細描述最佳地理解本揭露的態樣。應注意，根據行業中的標準實踐，未按比例繪製各種特徵。實務上，為了論述清楚起見，各種特徵的尺寸可以任意增加或減小。 圖1為根據本揭露部分實施方式的微影系統的示意圖。 圖2A為根據本揭露部分實施方式的光罩護膜的示意圖。 圖2B繪示根據本揭露部分實施方式的光罩護膜的折射率對波長關係圖。 圖3為根據本揭露部分實施方式的檢測方法的流程圖。 圖4A為根據本揭露部分實施方式的低同調光干涉檢測系統的示意圖。 圖4B為根據本揭露部分實施方式的被檢測的光罩護膜的示意圖。 圖5A為根據本揭露部分實施方式的檢測方法的光學檢測分析的實施方塊圖。 圖5B為圖5A的光學檢測分析的步驟的一實施方式的一流程圖。 圖6A以及圖6B分別繪示根據本揭露部分實施方式使用S偏振光以及P偏振光量測的光罩護膜的群組延遲頻譜圖。 圖7A繪示根據本揭露部分實施方式的一第一薄膜的群組延遲頻譜的差。 圖7B繪示根據本揭露部分實施方式的未經拉伸的第二薄膜的群組延遲頻譜的差。 圖7C繪示根據本揭露部分實施方式的經拉伸的第二薄膜的群組延遲頻譜的差。 圖8A繪示根據本揭露部分實施方式之群組延遲差的幅度對光罩護膜位置的關係圖。 圖8B繪示根據本揭露部分實施方式之薄膜厚度對光罩護膜位置的關係圖。 圖8C繪示根據本揭露部分實施方式之經薄膜厚度校正後的群組延遲差的幅度對光罩護膜位置的關係圖。 Aspects of the present disclosure are best understood from the following Detailed Description when read with the accompanying drawings. It should be noted that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or decreased for clarity of discussion. FIG. 1 is a schematic diagram of a lithography system according to some embodiments of the present disclosure. FIG. 2A is a schematic diagram of a pellicle according to some embodiments of the present disclosure. FIG. 2B is a graph showing the relationship between refractive index and wavelength of a pellicle according to some embodiments of the present disclosure. FIG. 3 is a flowchart of a detection method according to some embodiments of the present disclosure. FIG. 4A is a schematic diagram of a low-coherence optical interference detection system according to some embodiments of the present disclosure. FIG. 4B is a schematic diagram of an inspected pellicle according to some embodiments of the present disclosure. FIG. 5A is a block diagram illustrating an implementation of an optical detection analysis of a detection method according to some embodiments of the present disclosure. FIG. 5B is a flowchart of an embodiment of the steps of the optical detection analysis of FIG. 5A . FIGS. 6A and 6B respectively illustrate group retardation spectra of pellicles measured using S-polarized light and P-polarized light according to some embodiments of the present disclosure. FIG. 7A illustrates the difference in group delay spectrum of a first thin film according to some embodiments of the present disclosure. FIG. 7B shows the difference in group retardation spectra of the unstretched second film according to some embodiments of the present disclosure. FIG. 7C illustrates the difference in group retardation spectra of the stretched second film according to some embodiments of the present disclosure. FIG. 8A is a graph illustrating the relationship between the magnitude of the group retardation difference and the position of the pellicle according to some embodiments of the present disclosure. 8B is a graph illustrating film thickness versus pellicle position according to some embodiments of the present disclosure. FIG. 8C is a graph illustrating the magnitude of group retardation difference after film thickness correction versus pellicle position according to some embodiments of the present disclosure.

國內寄存資訊(請依寄存機構、日期、號碼順序註記) 無 國外寄存資訊(請依寄存國家、機構、日期、號碼順序註記) 無 Domestic deposit information (please note in order of depositor, date, and number) none Overseas storage information (please note in order of storage country, institution, date, and number) none

220:光罩護膜 220: mask protective film

300:檢測系統 300: detection system

310:光源 310: light source

320:準直鏡 320: collimating mirror

330:偏振片 330: Polarizer

340:分光鏡 340: beam splitter

350:物件聚焦鏡 350: Object Focusing Mirror

360:物件反射鏡 360: Object Mirror

370:參考聚焦鏡 370: Reference focusing mirror

380:參考反射鏡 380:Reference Mirror

390:聚光透鏡 390: Concentrating lens

400:光譜儀感測器 400: Spectrometer sensor

410:掃描平台 410:Scan platform

420:處理器 420: Processor

MC:鏡位置控制器 MC: mirror position controller

PC:偏振態調整器 PC: Polarization state adjuster

OL:物件光線 OL: object light

OLP:聚光點 OLP: Spotlight

RL:參考光線 RL: reference ray

X:方向 X: direction

Y:方向 Y: Direction

Z:方向 Z: Direction

Claims (10)

一種光罩護膜檢測方法，包含：以一低同調光干涉系統，分別使用一第一偏振光以及一第二偏振光，量測一光罩護膜的複數個區域，以分別獲得每一該些區域的一第一偏振態色散資訊以及一第二偏振態色散資訊，其中該第一偏振光的偏振態不同於該第二偏振光的偏振態；將每一該些區域的該第一偏振態色散資訊以及該第二偏振態色散資訊相減，而獲得每一該些區域的一偏振態色散資訊差；根據至少每一該些區域的該偏振態色散資訊差，判斷該光罩護膜是否合格；以及將合格的該光罩護膜裝設至一光罩上。 A method for inspecting a pellicle film, comprising: using a low-coherence optical interference system, respectively using a first polarized light and a second polarized light, to measure a plurality of regions of a pellicle film, so as to obtain each of the A first polarization state dispersion information and a second polarization state dispersion information of some regions, wherein the polarization state of the first polarized light is different from the polarization state of the second polarized light; the first polarization of each of the regions Subtracting the polarization state dispersion information and the second polarization state dispersion information to obtain a polarization state dispersion information difference of each of the regions; according to the polarization state dispersion information difference of at least each of the regions, the reticle pellicle is judged whether it is qualified; and installing the qualified photomask pellicle on a photomask. 如請求項1所述之光罩護膜檢測方法，其中該第一偏振態色散資訊為一第一偏振態群組延遲頻譜，該第二偏振態色散資訊為一第二偏振態群組延遲頻譜。 The photomask pellicle detection method as described in Claim 1, wherein the first polarization state dispersion information is a first polarization state group delay spectrum, and the second polarization state dispersion information is a second polarization state group delay spectrum . 如請求項1所述之光罩護膜檢測方法，其中該第一偏振光與該第二偏振光為線偏振光，且該第一偏振光的一偏振方向垂直於該第二偏振光的一偏振方向。 The photomask pellicle detection method as described in Claim 1, wherein the first polarized light and the second polarized light are linearly polarized light, and a polarization direction of the first polarized light is perpendicular to a direction of the second polarized light polarization direction. 如請求項1所述之光罩護膜檢測方法，其中將合格的該光罩護膜裝設至該光罩上包含： 將該光罩護膜黏貼至一框架；以及將該框架黏貼至該光罩。 The photomask pellicle detection method as described in claim 1, wherein installing the qualified photomask pellicle on the photomask includes: sticking the mask pellicle to a frame; and sticking the frame to the mask. 如請求項1所述之光罩護膜檢測方法，更包含：依據該些區域的該些偏振態色散資訊差，計算一偏振態色散資訊差梯度，其中判斷該光罩護膜是否合格包含：根據該偏振態色散資訊差梯度以及每一該些區域的該偏振態色散資訊差，判斷該光罩護膜是否合格。 The photomask pellicle detection method as described in claim 1 further includes: calculating a polarization state dispersion information difference gradient according to the polarization state dispersion information differences of the regions, wherein judging whether the photomask pellicle is qualified includes: According to the polarization state dispersion information difference gradient and the polarization state dispersion information difference of each of the regions, it is judged whether the photomask pellicle is qualified. 如請求項1所述之光罩護膜檢測方法，更包含：將該每一該些區域的該第一偏振態色散資訊以及該第二偏振態色散資訊相加，並除以該光罩護膜的一平均色散折射率，以獲得每一該些區域的一厚度資訊，其中判斷該光罩護膜是否合格包含：根據每一該些區域的該第一偏振態色散資訊、該第二偏振態色散資訊、該偏振態色散資訊差以及該厚度資訊，判斷該光罩護膜是否合格。 The photomask pellicle detection method as described in Claim 1, further comprising: adding the first polarization state dispersion information and the second polarization state dispersion information of each of the regions, and dividing by the photomask pellicle An average dispersion refractive index of the film, to obtain a thickness information of each of the regions, wherein judging whether the photomask pellicle is qualified includes: according to the first polarization state dispersion information of each of the regions, the second polarization The state dispersion information, the polarization state dispersion information difference and the thickness information are used to determine whether the photomask pellicle is qualified. 一種光罩護膜檢測方法，包含：以一低同調光干涉系統，量測一光罩護膜的複數個區域，以獲得每一該些區域的一群組延遲頻譜；將每一該些區域的該群組延遲頻譜除以該光罩護膜的 一平均色散折射率，以獲得每一該些區域的一厚度資訊；根據該些區域的該些厚度資訊，判斷該光罩護膜是否合格；以及將合格的該光罩護膜裝設至一光罩上。 A method for detecting a mask pellicle, comprising: using a low-coherence optical interference system to measure a plurality of regions of a pellicle of a mask to obtain a group delay spectrum of each of these regions; The group delay spectrum divided by the reticle pellicle's an average dispersion refractive index, to obtain a thickness information of each of the regions; according to the thickness information of the regions, it is judged whether the photomask pellicle is qualified; and the qualified photomask pellicle is mounted on a on the photomask. 如請求項7所述之光罩護膜檢測方法，其中該低同調光干涉系統包含一低同調光源，該低同調光源提供的光線的同調長度小於20微米。 The photomask pellicle inspection method as described in Claim 7, wherein the low coherence optical interference system includes a low coherence light source, and the coherence length of the light provided by the low coherence light source is less than 20 microns. 一種光罩護膜檢測系統，包含：一白光光源；複數個干涉儀光學組件，用以結合一物件光以及一參考光，其中該物件光以及該參考光來自該白光光源；一光譜儀感測器，用以紀錄一干涉資訊；一偏振片組件，用以控制該物件光以及該參考光係為一第一偏振態或一第二偏振態；以及一處理器，電性連接該光譜儀感測器以及該偏振片組件，該處理器用以：使該物件光以及該參考光係為該第一偏振態，取得一第一干涉資訊；使該物件光以及該參考光係為該第二偏振態，取得一第二干涉資訊；以及分析該第一干涉資訊以及該第二干涉資訊，以分別獲得一第一偏振態色散資訊以及一第二偏振態色散資訊；以 及計算該第一偏振態色散資訊、該第二偏振態色散資訊以及一平均色散折射率，以判斷一光罩護膜是否合格。 A photomask pellicle inspection system, comprising: a white light source; a plurality of interferometer optical components for combining an object light and a reference light, wherein the object light and the reference light come from the white light source; a spectrometer sensor , used to record an interference information; a polarizer assembly, used to control the object light and the reference light system to be a first polarization state or a second polarization state; and a processor, electrically connected to the spectrometer sensor and the polarizer assembly, the processor is used to: make the object light and the reference light be in the first polarization state, obtain a first interference information; make the object light and the reference light be in the second polarization state, obtaining a second interference information; and analyzing the first interference information and the second interference information to respectively obtain a first polarization state dispersion information and a second polarization state dispersion information; And calculate the first polarization state dispersion information, the second polarization state dispersion information and an average dispersion refractive index to judge whether a mask protective film is qualified. 如請求項9所述之光罩護膜檢測系統，其中該第一偏振態與該第二偏振態為線偏振態，且該第一偏振態的一偏振方向垂直於該第二偏振態的一偏振方向。 The photomask pellicle inspection system as described in claim 9, wherein the first polarization state and the second polarization state are linear polarization states, and a polarization direction of the first polarization state is perpendicular to a polarization direction of the second polarization state polarization direction.
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