201003055 九、發明說明： 【發明所屬之技術領域】 本發明係有關一種光學量測技術，尤其是指一種可以 改變光線投射至物體之角度之散射光學量測方法與裝置。 【先前技術】 先進製程控制要能線上檢測（in-situ)控制之參數，並 Γ 將此參數之檢測結果回授調整製程參數，以提高生產良 率。目前半導體製造的特徵線寬（future si ze)已經進步到 65nm ’此尺寸已經小於光學繞射極限，傳統光學顯微鏡無 法清楚成像很難做到先進製程控制的要求。雖然掃描式電 子顯微鏡（scanning electron microscope，SEM)及原子力顯 微鏡（atomic force microscope, AFM)的解析能力皆可達到 此需求，但是由於SEM之電子束會使得樣品表面累積電荷 而破壞樣品。並且SEM只可檢測到表層結構而無法檢測到 Ο 内層結構。而AFM最大的問題在於檢測速度過慢，無法使 用於線上檢測，同樣的AFM也只能檢測表面結構，而無法 檢測内層結構。 而散射術本質為光學式非接觸式檢測技術，且具有優 於光學繞射極限的解析能力，經由演算法回歸計算可得出 樣品多層結構，檢測速度亦適合進行線上檢測。散射術為 新一代半導體先進製程控制檢測技術的重要選項之一，目 前也已經有部分半導體廠商將散射術應用於線上檢測。 在習用技術之散射檢測技術中，例如：美國國家標準 5 201003055 實驗室（NIST)之 H. J. Patrick，R. Attota, B. M. Barnes, et al. “Scatterfield Microscopy Using Back Focal Plane Imaging with an Engineered Illumination201003055 IX. INSTRUCTIONS: [Technical Field] The present invention relates to an optical measurement technique, and more particularly to a scattering optical measurement method and apparatus that can change the angle at which light is projected onto an object. [Prior Art] Advanced process control should be able to in-situ control the parameters of the control, and 回 feedback the test results of this parameter to adjust the process parameters to improve production yield. At present, the feature line width of semiconductor manufacturing has progressed to 65 nm. This size is already smaller than the optical diffraction limit. Traditional optical microscopes cannot clearly understand that imaging is difficult to achieve advanced process control requirements. Although the analytical capabilities of a scanning electron microscope (SEM) and an atomic force microscope (AFM) can be achieved, the electron beam of the SEM causes the sample to accumulate charge and destroy the sample. And the SEM can only detect the surface structure and cannot detect the Ο inner structure. The biggest problem with AFM is that the detection speed is too slow to be used for on-line detection. The same AFM can only detect the surface structure and cannot detect the inner structure. The scattering technique is essentially an optical non-contact detection technology, and has an analytical ability superior to the optical diffraction limit. The multi-layer structure of the sample can be obtained by algorithm regression calculation, and the detection speed is also suitable for on-line detection. Scattering is one of the important options for next-generation semiconductor advanced process control inspection technology, and some semiconductor manufacturers have applied scatter to on-line inspection. In the scattering detection technology of conventional technology, for example: American National Standard 5 201003055 Laboratory (NIST) H. J. Patrick, R. Attota, B. M. Barnes, et al. “Scatterfield Microscopy Using Back Focal Plane Imaging with an Engineered Illumination
Field,” Proc. of SPIE， vol· 6152， 61520J (2006)。 該技術架構如圖一所示，此系統1使用亮場顯微鏡架構， 並且有一片光罩1 0。此光罩經由中繼（relay )系統1 1成像 在物鏡12的背焦面上。藉由精密的控制機構來控制光罩Field,” Proc. of SPIE, vol· 6152, 61520J (2006). The technical architecture is shown in Figure 1. This system 1 uses a bright field microscope architecture and has a reticle 10. This reticle is relayed ( The system 11 is imaged on the back focal plane of the objective lens 12. The mask is controlled by a precise control mechanism.
11的移動’改變照明光13人射的角度，再藉由影像擁取 裝置14紀錄不同角度的散射光。 穴㈡牙判W〖，Ubl，bW似所揭露之一鍤 檢測裝置’在該技射制—干涉織鏡_， 的：構控制位置改變樣品位置或是改變參考面位▲，：摆 :::的入射光照明於樣品上，其他的 並不會照射於檨CT。山& 、硬壞性干涉 不同的角度人射， 主要技術在於使用干涉架構選擇 光。 11且可由干涉__特以度的反射The movement of 11 changes the angle at which the illumination light 13 is shot, and the image capturing means 14 records the scattered light at different angles. Hole (2) tooth judgment W 〖, Ubl, bW like one of the disclosed 锸 detection devices 'in this technical shooting - interference spectacles _,: control position to change the sample position or change the reference surface ▲, : pendulum:: : The incident light illuminates the sample, and the other does not illuminate the 檨CT. Mountain & Hard and Bad Interference Different angles of human shooting, the main technique is to use the interference architecture to select light. 11 and can be reflected by the interference __
【發明内容】 本發明提供—Μ 射術整合到亮場顯4:==置’其係將散 整合更簡易且具有问“放射7^子檢剛與製程設備 之方便性。 €定之架構’以提昇檢測流程規劃 本發明提供〜 散射儀架構，其^ f射光學量測方法與裝置，其係簡化 學成像系統，控制ς間光調制器調變相位配合固定之光 先點啊入射角照射至待剛樣品，： 201003055 避免運動機構的設置，減少精密位置控制的需求，並且具 有穩定及簡單之架構以易於與其他製程設備整合。 在一實施例中，本發明提供一種散射光學量測裝置， 包括：一光源模組，其係可提供一光場；一物鏡組，其係 具有一背焦面，該物鏡組係設置於一待測物之一側；一空 間光調制器，其係對該光場之一光學特徵進行調制以形成 一第一光束聚焦於該背焦面上，該第一光束經由該物鏡組 投射於該待測物上以形成一第二光束聚焦於該背焦面上； 以及一陣列偵測裝置，其係記錄該背焦面上對應該第二光 束之光學影像。 在另一實施例中，本發明提供一種散射光學量測方 法，其係包括有下列步驟：提供一光場；調制該光場之一 光學特徵，使該光場聚焦於一物鏡組之背焦面上以形成一 第一光束；使該第一光束投射於一待測物上以形成一第二 光束聚焦於該背焦面上；記錄該背焦面上對應該第二光束 之光學影像；以及改變該第一光束聚焦於該背焦面上之位 置。 【實施方式】 為使貴審查委員能對本發明之特徵、目的及功能有 更進一步的認知與暸解，下文特將本發明之裝置的相關細 部結構以及設計的理念原由進行說明，以使得審查委員可 以了解本發明之特點，詳細說明陳述如下： 請參閱圖二所示，該圖係為本發明之散射光學量測方 7 201003055 法流程示意圖。該方法2係包括有下列步驟，首先進行步 驟20提供一光場。在一實施例中，更可以將該光場進行準 直以及偏極化的調制動作，使得該光場形成一準直之線性 偏極光。接下來進行步驟21，調制該光場之一光學特徵， 使該光場聚焦於一物鏡組之背焦面上以形成一第一光束。 步驟21中所謂之光學特徵係指該光場之振幅、相位或者是 前述兩者的組合。接著進行步驟22，使該第一光束投射於 一待測物上以形成一第二光束聚焦於該背焦面上。然後進 行步驟23，記錄該背焦面上對應該第二光束之光學影像。 最後透過步驟24改變該第一光束聚焦於該背焦面上之位 置。 由於散射術量測表面形貌的原理為，使用單波長或不 同波長的光，由不同角度入射，.經由待測物散射出來，將 0階或高階的繞射光記錄下來。依據不同角度入射得到0 階或高階繞射光強度，或是不同·波長得到的0階或高階繞 射光強度所形成圖譜，經由資料庫比對或是電磁方程式反 解運算，估算出樣品形貌之參數。所示，藉由步驟23與 24之反覆執行，以完整記錄關於該待測物上之特定位置於 該背焦面上之完整影像資訊，以作為估算樣品形貌之參數。 請參閱圖三所示，該圖係為本發明之散射光學量測裝 置實施例示意圖。該裝置3包括有一光源模組30、一物鏡 組31、一空間光調制器32以及一陣列偵測裝置33。該光 源模組30係可提供一光場91，在本實施例中，該光源模 組30係可選擇為雷射光模組或者是發光二極體發光模 組，但不以此為限。該物鏡組31，其係具有一背焦面310， 8 201003055 該物鏡組31係設置於一待測物90之一側。該空間光調制 器32，其係對該光場91之一光學特徵進行調制以形成一 第一光束92聚焦於該背焦面310上，該第一光92束經由 該物鏡組31投射於該待測物90上以形成一第二光束93聚 焦於該背焦面310上。在本實施例中，該空間光調制器 32(Spatial Light Modulator, SLM)係為液晶調制元件 (1 iquid crystal modulator )，例如：H0L0EYE 公司所售 之商業產品LC-R系列的空間光調制器。 1 在本實施例中，該光源模組30與該空間光調制器32 間更可以設置有一透鏡組34以及一第一分光元件35。該 透鏡組34主要是用來準直化該光場91。而該第一分光元 件35係將準直化之光場分光至該空間光調制器32上。此 外，在透鏡組34與該第一分光元件35間更具有一偏光元 件36，其係偏極化被準直的光場。在本實施例中，該偏光 元件36係為一線性偏光元件。該陣列偵測裝置33，其係 記錄該背焦面310上對應該第二光束之光學影像，該陣列 Cj 偵測裝置33係可選擇為電耦合元件（CCD)或者是互補式金 .氧半元件（CMOS)。在圖三中，該陣列偵測裝置33與該物鏡 組31間更具有一第二分光元件37以及一透鏡組38。該第 二分光元件37係將該第一光束92導引至該背焦面310 上。而該透鏡組38，其係將由該背焦面310所發散之第二 光束93聚焦至該陣列偵測裝置33上。 接下來說明空間光調制器之運作方式，請參閱圖四所 示，該圖係為空間光調制器的示意圖。其中工作區320位 於空間光調制器32主體上。工作區320是由許多的調制單 201003055 元（in〇dulati〇nce11)所構成，其係可藉由控制模擬成菲沒 爾透鏡（Fresnel ien，效果以對光的振幅、相位或者是 兩者組合進行觸。如圖五所示，該圖係為空間光調制哭 =光場進行振幅調制（AmpUtude M〇duiatiQn)示意圖 中’圖五之水平轴代表著調制單元沿 一方向之位置分佈（如 圖四之中心绫α 、 斤！過之調制單元）’而垂直轴代表振 幅。由圖五可以瞭組，甘丄‘丄 01 , . ^ 、瞭解其中垂直軸之值為0代表不透光，1 、r 王透光，因此藉由控制每個調制單元的透光程 度即可將空間光調制器32模擬成菲淫爾透鏡，使入射的 平面光匯聚在物鏡組31之背焦面310上。 如圖七A與圖七B所示，當位i 95的聚焦光束於待測 物上所1生之散射光訊號被陣列偵測裝置擷取完畢之後， 可以改t：空間光調制器之調制中心位置，以改變第一光束 聚焦於$焦面之位置。如圖七A中，當調制中心、位置由95 移動至96時，則第一光束之中心位置也會跟著改變。如在 圖七B中，經過調變之後，第一光束犯會變成第一光束 92 。因此，第一光束聚焦於背焦面310上的焦點也跟著 移動，不同的焦點位置則入射至待測物9 〇上的角度也將不 同，如圖八中，第一光束92，經由待測物9〇所散射之第 二光束93’之聚焦於背焦面310之位置也隨之改變。藉由 上述方式’可以透過控制調制的中心點位置，使其第一光 束聚焦於背焦面31〇上的不同位置，即以達到不同角度入 射至待測物90上的功能。 同樣地，如圖六所示，該圖係為空間光調制器對光場 進行相位調制（Phase Modulation)示意圖。其中，圖六之 201003055 水平軸代表著調制單元沿一方向之位置（如圖四之中心線 94所經過之調制單元）；而垂直軸代表相位。藉由控制每 個調制單元的相位值，從0至2 7Γ的調制，使該空間光調 制器模擬成菲涅爾透鏡的效果，進而控制第一光束聚焦於 背焦面上的不同位置。與圖七A相同，為了改變焦點在背 焦面310上的位置，只需要改變調制的中心位置。再回到 圖三所示，不管是圖五或者是圖六的調變方式，經由待測 物反射之第二光束經透鏡匯聚在陣列偵測裝置33上，不同 的入射角入射至待測物90上，則在陣列偵測裝置33上將 匯聚在不同的聚點位置，如圖九中的光束93及光束93’ 所示。 惟以上所述者，僅為本發明之實施例，當不能以之限 制本發明範圍。即大凡依本發明申請專利範圍所做之均等 變化及修飾，仍將不失本發明之要義所在，亦不脫離本發 明之精神和範圍，故都應視為本發明的進一步實施狀況。 綜合上述，本發明提供之散射光學量測方法與裝置， 以輕易與製程設備整合且具有相對於傳統散射儀較為簡單 穩定之架構，對於檢測流程規劃較為方便。因此已經可以 提高該產業之競爭力以及帶動週遭產業之發展，誠已符合 發明專利法所規定申請發明所需具備之要件，故爰依法呈 提發明專利之申請，謹請 貴審查委員允撥時間惠予審 視5並賜准專利為禱。 11 201003055 【圖式簡單說明】 圖一係為習用之亮場顯微鏡架構示意圖。 圖二係為本發明之散射光學量測方法流程示意圖。 圖三係為本發明之散射光學量測裝置實施例示意圖。 圖四係為空間光調制器的示意圖。 圖五係為空間光調制器對光場進行振幅調制（Amp 1 i tude Modulation)示意圖。 圖六係為空間光調制器對光場進行相位調制（Phase Modulation)示意圖。 圖七A與圖七B係為改變模擬Fresne 1 1 ens中心位置示 意圖。 圖八係為散射光聚焦位置改變示意圖。 圖九係為陣列偵測裝置擷取背焦面上不同聚焦位置之散射 光示意圖。 1./ 【主要元件符號說明】 1_系統 10-光罩 11 -中繼系統 12- 物鏡 13- 照明光 14- 影像擷取裝置 2-散射光學量測方法 12 201003055 » 20〜24-步驟 3-散射光學量測裝置 3 0 -光源模組 3卜物鏡組 310 -背焦面 32-空間光調制器 320-工作區 / 33-陣列偵測裝置SUMMARY OF THE INVENTION The present invention provides that Μ 术 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合 整合The invention provides a scatterometer architecture, a method and a device for measuring optical ray, which is a simplified imaging system, and controls the inter-turn light modulator to adjust the phase to match the fixed light first point and the incident angle illumination. Until the sample, 201003055 avoids the setting of the motion mechanism, reduces the need for precise position control, and has a stable and simple structure for easy integration with other process equipment. In one embodiment, the present invention provides a scattering optical measuring device The method includes: a light source module, which can provide a light field; an objective lens group having a back focal plane, the objective lens set is disposed on one side of an object to be tested; and a spatial light modulator Modulating an optical characteristic of the light field to form a first light beam focused on the back focus surface, the first light beam being projected onto the object to be tested via the objective lens group to form a second beam focus And an array detecting device for recording an optical image corresponding to the second light beam on the back focal plane. In another embodiment, the present invention provides a scattering optical measuring method, which is The method comprises the steps of: providing a light field; modulating an optical characteristic of the light field, focusing the light field on a back focal plane of an objective lens group to form a first light beam; and projecting the first light beam to be tested Forming a second light beam on the back focus surface; recording an optical image corresponding to the second light beam on the back focus surface; and changing a position at which the first light beam is focused on the back focus surface. In order to enable the reviewing committee to have a further understanding and understanding of the features, objects and functions of the present invention, the relevant detailed structure of the device of the present invention and the concept of the design are explained below so that the reviewing committee can understand the present invention. The detailed description is as follows: Please refer to Figure 2, which is a schematic diagram of the scattering optical measurement method 7 201003055 of the present invention. The method 2 includes the following In the first step, a light field is provided in step 20. In an embodiment, the light field is further subjected to a collimating and polarizing modulation operation, so that the light field forms a collimated linear polarized light. 21, modulating an optical characteristic of the light field such that the light field is focused on a back focal plane of an objective lens group to form a first light beam. The so-called optical characteristic in step 21 refers to the amplitude, phase, or a combination of the two. Then proceeding to step 22, the first light beam is projected onto an object to be tested to form a second light beam focused on the back focus surface. Then step 23 is performed to record the back focus surface corresponding to Optical image of the second beam. Finally, the position of the first beam focused on the back focal plane is changed by step 24. The principle of measuring the surface topography by scatter is to use light of a single wavelength or different wavelengths, by different angles. Incident, by scattering from the object to be tested, the 0th order or higher order diffracted light is recorded. According to different angles of incidence, the 0th-order or high-order diffracted light intensity, or the 0th-order or high-order diffracted light intensity obtained by different wavelengths, can be used to estimate the sample morphology through database comparison or electromagnetic equation inverse solution operation. parameter. As shown, the repeated execution of steps 23 and 24 is performed to completely record the complete image information about the specific position on the object to be measured on the back focus surface as a parameter for estimating the sample topography. Please refer to FIG. 3, which is a schematic diagram of an embodiment of a scattering optical measuring device of the present invention. The device 3 includes a light source module 30, an objective lens group 31, a spatial light modulator 32, and an array detecting device 33. The light source module 30 can provide a light field 91. In this embodiment, the light source module 30 can be selected as a laser light module or a light emitting diode light emitting module, but is not limited thereto. The objective lens set 31 has a back focal plane 310, 8 201003055. The objective lens set 31 is disposed on one side of a test object 90. The spatial light modulator 32 modulates an optical characteristic of the light field 91 to form a first light beam 92 that is focused on the back focal plane 310. The first light 92 beam is projected through the objective lens group 31. A second light beam 93 is formed on the object to be tested 90 to be focused on the back focal plane 310. In the present embodiment, the spatial light modulator (SLM) is a liquid crystal modulation element (1), for example, a commercial light product LC-R series spatial light modulator sold by H0L0EYE. In this embodiment, a lens group 34 and a first beam splitting element 35 may be disposed between the light source module 30 and the spatial light modulator 32. The lens group 34 is primarily used to collimate the light field 91. The first beam splitting element 35 splits the collimated light field onto the spatial light modulator 32. Further, between the lens group 34 and the first beam splitting element 35, there is further provided a polarizing element 36 which is a polarized light field which is collimated. In the present embodiment, the polarizing element 36 is a linear polarizing element. The array detecting device 33 records the optical image corresponding to the second beam on the back focal plane 310. The array Cj detecting device 33 can be selected as an electrical coupling element (CCD) or a complementary gold. Component (CMOS). In FIG. 3, the array detecting device 33 and the objective lens group 31 further have a second beam splitting element 37 and a lens group 38. The second beam splitting element 37 directs the first beam 92 onto the back focal plane 310. The lens group 38 focuses the second light beam 93 diverged by the back focal plane 310 onto the array detecting device 33. Next, the operation of the spatial light modulator will be described. Please refer to Figure 4, which is a schematic diagram of the spatial light modulator. The work area 320 is located on the main body of the spatial light modulator 32. The working area 320 is composed of a plurality of modulation sheets 201003055 (in〇dulati〇nce11), which can be controlled by simulation into a Fischer lens, the effect is to the amplitude, phase or combination of the two. As shown in Figure 5, the figure is the spatial light modulation cry = light field amplitude modulation (AmpUtude M〇duiatiQn) schematic diagram 'The horizontal axis of Figure 5 represents the position distribution of the modulation unit in one direction (Figure The center of the four 绫α, 斤! Over the modulation unit) 'and the vertical axis represents the amplitude. From Figure 5 can be group, Ganzi '丄01, . ^, understand that the value of the vertical axis is 0 means opaque, 1 The r light is transmitted, so that the spatial light modulator 32 can be modeled as a Philippine lens by controlling the degree of light transmission of each modulation unit, and the incident planar light is concentrated on the back focal plane 310 of the objective lens group 31. As shown in FIG. 7A and FIG. 7B, after the scattered light signal generated by the focused beam of the position i 95 on the object to be tested is captured by the array detecting device, the modulation of the spatial light modulator can be changed: Center position to change the first beam to focus on The position of the focal plane is as shown in Fig. 7A. When the modulation center and position are moved from 95 to 96, the center position of the first beam will also change. As shown in Fig. 7B, after the modulation, the first The beam will become the first beam 92. Therefore, the focus of the first beam focused on the back focal plane 310 will also follow, and the angle of incidence of the different focus positions onto the object 9 will be different, as shown in Figure 8. The position of the first light beam 92, which is focused on the back focus surface 310 by the second light beam 93' scattered by the object to be tested 9, is also changed. By the above method, the position of the center point of the modulation can be controlled to be The first light beam is focused on different positions on the back focal plane 31, that is, to achieve the function of being incident on the object to be tested 90 at different angles. Similarly, as shown in Fig. 6, the figure is a spatial light modulator to the light field. A schematic diagram of Phase Modulation is performed, wherein the horizontal axis of 201003055 of FIG. 6 represents the position of the modulation unit in one direction (the modulation unit passed through the center line 94 of FIG. 4); and the vertical axis represents the phase. Each modulation sheet The phase value of the element, from 0 to 2 Γ, modulates the spatial light modulator to simulate the effect of a Fresnel lens, thereby controlling the first beam to focus on different positions on the back focal plane. As in Figure 7A, To change the position of the focus on the back focal plane 310, only need to change the center position of the modulation. Returning to Figure 3, whether it is the modulation mode of Figure 5 or Figure 6, the second beam reflected by the object to be tested The lens is concentrated on the array detecting device 33. When different incident angles are incident on the object to be tested 90, the array detecting device 33 will be concentrated at different gathering points, such as the beam 93 and the beam 93' in FIG. The above is only the embodiment of the present invention, and the scope of the present invention is not limited thereto. It is to be understood that the scope of the present invention is not limited to the spirit and scope of the present invention, and should be considered as further implementation of the present invention. In summary, the scattering optical measuring method and device provided by the present invention are easy to integrate with the process equipment and have a relatively simple and stable structure relative to the conventional scatterometer, and are convenient for the inspection process planning. Therefore, it has been possible to improve the competitiveness of the industry and promote the development of the surrounding industries. Cheng has already met the requirements for applying for inventions as stipulated in the invention patent law. Therefore, the application for invention patents is submitted according to law. Hui will review 5 and grant the patent as a prayer. 11 201003055 [Simple description of the diagram] Figure 1 is a schematic diagram of the bright field microscope structure. Figure 2 is a schematic flow chart of the scattering optical measurement method of the present invention. Figure 3 is a schematic view of an embodiment of the scattering optical measuring device of the present invention. Figure 4 is a schematic diagram of a spatial light modulator. Figure 5 is a schematic diagram of amplitude modulation (Amp 1 i tude Modulation) of a light field by a spatial light modulator. Figure 6 is a schematic diagram of the phase modulation of the light field by the spatial light modulator. Figure 7A and Figure 7B show the change of the simulated Fresne 1 1 ens center position. Figure 8 is a schematic diagram showing the change of the focus position of the scattered light. Figure 9 is a schematic diagram of the scattered light captured by the array detecting device at different focus positions on the back focal plane. 1./ [Main component symbol description] 1_System 10 - Mask 11 - Relay system 12 - Objective lens 13 - Illumination light 14 - Image capture device 2 - Scattering optical measurement method 12 201003055 » 20~24-Step 3 - Scattering optical measuring device 30 - Light source module 3 objective lens group 310 - Back focal plane 32 - Spatial light modulator 320 - Working area / 33 - Array detecting device
I 34、38-透鏡組 35-第一分光元件 3 6 -偏光元件 37-第二分光元件 39-平台 90-待測物 91 -光場 1'' 92、92’ -第一光束 • 93、93’ -第二光束 . 9 4-中心線 95、96-中心位置 13I 34, 38-lens group 35 - first beam splitting element 3 6 - polarizing element 37 - second beam splitting element 39 - platform 90 - object to be tested 91 - light field 1 '' 92, 92' - first beam • 93, 93' - second beam. 9 4-center line 95, 96 - center position 13