200907292 九、發明說明： 【發明所屬之技術領域】 本發明係關於圖案之間距測定裝置及方法，特別是關 於測定形成於物體表面之線/空間圖案（以下，亦表示為「L / S圖案」）之間距的裝置及方法，以及檢查物體表面之裝 置及方法。 【先前技術】 習知之間距測定裝置，係將單波長之光照射於L/s 圖案’並檢測在L/S圖案反射之高次繞射光（±1次繞射光， ±2次繞射光等），根據檢測出之繞射光的光強度測定s 圖案之間距。 【發明内容】200907292 IX. Description of the Invention: [Technical Field] The present invention relates to a device for measuring the distance between patterns, and more particularly to measuring a line/space pattern formed on the surface of an object (hereinafter also referred to as "L / S pattern") Apparatus and method for spacing, and apparatus and method for inspecting the surface of an object. [Prior Art] A conventional distance measuring device irradiates a single-wavelength light to an L/s pattern' and detects high-order diffracted light reflected in the L/S pattern (±1 times of diffracted light, ±2 times of diffracted light, etc.) The distance between the s patterns is determined based on the detected light intensity of the diffracted light. [Summary of the Invention]
在習知技術中，如上述，係採用檢測在L/s圖案反 射之高次繞射光的構成。是以，L/s圖案之間距愈短，為 2足布拉格定律之條件，愈需要使用短波長之光。一般而 言，使用短波長之光的裝置，容易變得昂貴。 又，例如測定形成於光阻之L/s圖案之間距時，短 波長之光有時亦會使光阻感光。進而，於光阻面内l/s =案具有起伏（粗縫度）時，因L/S圖案之粗糖度的影響， &成所檢測出之繞射反射光的 4^ . Λ 5$度降低，進而間距之測定 1又降低或間距之測定本身無法進行。 本發明係有寥於上述之課題， ^其目的在於提供能使用 200907292In the prior art, as described above, the configuration of detecting high-order diffracted light reflected in the L/s pattern is employed. Therefore, the shorter the distance between the L/s patterns, the condition of the 2-leg Bragg's law, the shorter the need to use short-wavelength light. In general, devices that use short-wavelength light tend to become expensive. Further, for example, when the distance between the L/s patterns formed in the photoresist is measured, light of a short wavelength sometimes causes the photoresist to be light-sensitive. Further, when the l/s = case has an undulation (roughness) in the photoresist surface, due to the influence of the coarse sugar content of the L/S pattern, & is the detected diffraction light 4^. Λ 5$ The degree is lowered, and the measurement of the pitch 1 is further lowered or the measurement of the pitch itself cannot be performed. The present invention is related to the above problems, and its purpose is to provide usable use 200907292
較長波長之光來測定L/S 方法。 圖案之間距的間距測定裝置及 ’貝負上不受L/ S圖案 L/S圖案之間距的間距 又’本發明之目的在於提供 之粗糙度的影響，能高精度測定 測定裝置及方法。 為解決上述課題，本發明之第i形態提供測定線/空 間圖案之間距的間距測定裝置，其特徵在於，具備：昭射 ^統’用以切換至彡2個波長之光並照射於該線/空:圖 了，檢测系統，用以檢測在該線^/空間圖案反射之〇次繞 射光，以及測定系統，根據該檢測系統針對第丨波長所檢 測出之〇 :欠繞射光之光強度與針對帛2》皮長所檢測出之〇 次繞射光之光強度的強度比，測定該線/空間圖案之 距。 、 日 本發明之第2形態提供測定線/空間圖案之間距的間 距測定方法，其特徵在於，包含：照射步驟，用以切換至 少2個波長之光並照射於該線/空間圖案；檢測步驟，用 以檢測經由該照射步驟並在該線/空間圖案反射之〇次繞 射光；以及測定步驟，用以根據在該檢測步驟針對第1波 長所檢測出之〇次繞射光之光強度與針對第2波長所檢測 出之〇次繞射光之光強度的強度比，測定該線/空間圖案 之間距。 在本發明中，由於檢測在L/S圖案反射之0次繞射 光’因此’能使用較長波長之光作為照射光。其結果，與 為滿足布拉格定律之條件而使用短波長之光的習知技術相 200907292 比，能實現簡單構成之低價裝置。又，在本發明中，由於 使用較長波長之光作為朝S圖案之照射光，因此，在 測疋形成於光阻之L/S圖案之間距時，沒有使光阻感光 之危險性。 進一步，在本發明中，將朝L〆s圖案之照射光之波 長在至少2個》皮長間切換，根據針對帛丨《皮長所檢測出之 〇次繞射光之光強度與針對第2波長所檢測出t 〇次、繞射 光^光強度的強度匕，測定L/S B案之間距。其結果， 如實施形態所詳述，能實質上不$ L/s圖案之粗糙度的 影響，高精度測定L/S圖案之間距。 L實施方式】 (第1實施形態） 根據附圖說明本發明第1眘 S月弟1實麵形態。圖1係概略表示Longer wavelength light is used to determine the L/S method. The pitch measuring device between the patterns and the spacing between the L/S patterns are not affected by the distance between the L/S patterns. The purpose of the present invention is to provide a high-precision measurement measuring device and method by providing the influence of the roughness. In order to solve the above-described problems, the first aspect of the present invention provides a pitch measuring device for measuring a distance between line and space patterns, characterized in that the method includes: a camera system for switching to two wavelengths of light and irradiating the line /empty: The detection system is used to detect the secondary diffracted light reflected in the line/space pattern, and the measurement system, according to the detection system for the second wavelength: the light of the under-reduced light The intensity is compared with the intensity ratio of the intensity of the diffracted light detected for the 皮2" skin length, and the distance of the line/space pattern is determined. A second aspect of the invention of the present invention provides a method for measuring a pitch between measurement line/space patterns, comprising: an irradiation step of switching light of at least two wavelengths and irradiating the line/space pattern; and a detecting step, a step of detecting the diffracted light reflected by the illumination step and reflected in the line/space pattern; and a measuring step for determining the intensity of the light of the diffracted light detected for the first wavelength in the detecting step The intensity ratio of the light intensity of the secondary diffracted light detected by the two wavelengths is measured, and the distance between the line/space patterns is measured. In the present invention, since the zero-order diffracted light 'reflected' reflected in the L/S pattern can be detected, light of a longer wavelength can be used as the illumination light. As a result, compared with the conventional technique 200907292 which uses short-wavelength light to satisfy the conditions of the Bragg's law, a low-cost device having a simple configuration can be realized. Further, in the present invention, since light having a longer wavelength is used as the irradiation light toward the S pattern, there is no risk of the photoresist being photosensitive when the distance between the L/S patterns formed by the photoresist is measured. Further, in the present invention, the wavelength of the illumination light toward the L〆s pattern is switched between at least two skin lengths, according to the light intensity of the secondary diffracted light detected for the skin length and the second wavelength. The intensity 匕 of the t 〇 times and the diffracted light intensity was measured, and the distance between the L/SB cases was measured. As a result, as described in detail in the embodiment, the distance between the L/S patterns can be measured with high precision without substantially affecting the roughness of the L/s pattern. (Embodiment) (First Embodiment) A first embodiment of the present invention will be described with reference to the drawings. Figure 1 is a schematic representation
本發明第1實施形態之間距測定裝置的構成圖。圖2係概 略表示第！實施形態之間距測定裳置之測定對象之W 圖案的構成圖，⑷表示俯視圖，（b)表示沿⑷之、線Μ方 向亦即間距方向的截面圖。此外 此外，在圖2 ’為使說明易於 理解，僅表示測定對象之L/8 ®安山 豕〈s圖案中矩形狀之區域部分。 參照圖2 ’於沿物體j之 λΥ +面之表面所形成的L / S圖案12，係由圖2(a)中斜線邱m _ 「a 深。卩所不之凸部（以下，稱為 線部」）1 2a與圖2(a)中空白部所 „ A 研不之凹部（以下，稱為「空 間部」）12b構成。線部i2a及* 夂工間部】2b，同時沿與+X方 向及+Y方向成45度的方向，直線且Μ延伸。 200907292 換言之，L/S圖案12之長邊方向為與+χ方向及+γ 方向成45度的方向’ L/S圖案12之間距方向為與+χ方 向及-Υ方向成45度的方向。又，如圖2(b)所示，線部12a ，寬度尺寸Wa與空間部m之寬度尺寸猶相等。是以， 若以w來表示線部12a之間距方向之長度之寬度尺寸· 及空間部⑵之間距方向之長度之寬度尺寸Wb，則L/S 圖案1 2之間距p為2 w。 參照圖1，第1實施形態之間距測定裝置，係具備例 如K銀燈1之光源。來自水銀燈i之光，透過省略圖示之 橢圓反射鏡、準直透鏡等光學系統，射入波長選擇過減器 2。波長選擇過攄器2,係、具有使i線U=365nm)之光選擇 性透射的特性。 波長選擇過據器2，能於光路拆裝自如，且能與且有 不同特性之其他波長選擇過滤器2a，2b更換。具體而言， 波長選擇過滤H 2a具有使例如h、^u=4()5nm)之光選擇性 透射的特性，波長選擇過遽器2b具有使例如_λ=43 — 之光選擇性透射的特性。具有透過波長選擇過濾器“a或 孔選擇之波長之光，係射入偏振元件3。 X銀燈1係構成為可與例如供應波長又為“km 之光的Μ準分子雷射光源4切換。使用KrF準分子· :光源U作為光源時，來自KrF準分子雷射光源"之光田 .. 、束器等的光學系統，射入偏振元件3。 偏振兀件3,具有使例如具有與圖！ 向之光選擇性通過㈣# η 1之偏振方 特生。！過偏振元件3之直線偏振之 200907292 光，傾斜射入形成於沿物體11之XY平面之表面的L/ s 圖案12。 此處’射入L/ S圖案12之光的波長（在本實施形態中 λ =248，3 65，405，436nm)，設定為較長之波長。又，朝l /S圖案12之光之入射方向（在本實施形態為χ方向），設 定為與L/S圖案12之間距方向及長邊方向兩者交又的方 向。 進一步，射入L/S圖案12之光的偏振方向（在本實施 形態為與圖1之紙面垂直的γ方向）亦設定為與L/s圖案 12之間距方向及長邊方向兩者交叉的方向。如此，光源 Ula)、波長選擇過濾器2(2a，2b)、及偏振元件3構成用以 將直線偏振狀態之光在4個波長間切換並照射於L/s圖 案12的照射系統。 接焚來自照射系統（1〜3)之光照射，在L/ s圖案12反 射之〇次繞射光射入於滿足正交偏振條件的檢光元件（偏振 元件）4。檢光元件4具有使具有與朝L/s圖案12之入射 光之偏振方向正交之偏振方向之光選擇性通過的特性。經 由檢光元件4之既定直線偏振狀態的〇次繞射光，到達例 如如CCD之光檢測器（受光元件）5。以光檢測器5檢測出 射入之0次繞射光的光強度。 以此方式，檢光元件4及光檢測器5，構成用以在[ ，圖案12反射之〇次繞射光令，檢測出具有與朝 圖案12之入射光之偏振方向正交之偏振方向之〇次繞射 光的檢測系統。光檢測H 5之輸出，供應至作為訊號處理 200907292 P 疋系統6。在測定系统6中，如後述，根 統⑽針對第1波長所檢剛出之。次繞射光之光強度 對第Μ長所檢測出之0次繞射光之光強度的強度 出（測定）L/S圖案12之間距ρ。 ^ 此外於檢測系統（4,5)，之所以僅檢測出具有與朝^ /S圖案12之人射光之偏振方向正交之偏振方向的〇次雄 射光（偏振旋轉成分），料了去除雜訊成分之故。實際上^ 雖然無法完全阻擋具有與朝L/s圖案12之入射光之偏振 方向相同偏振方向（振動面）之光射人光檢測器5,但容許 因檢光元件4之容許製造誤差（公差）而射入之光。 在本實施形態之間距測定裝置，將照射於l/ $圖案12 之光的波長，在4個波長λ =248nm, λ =365nm，λ =4〇5nm A=436nm間切換，並針對各波長檢測出具有與朝圖 案12之入射光之偏振方向正交之偏振方向之〇次繞射光（偏 振旋轉成分）的光強度。此時，若將例如248nm之波長設 為基準波長，則針對基準波長（第〗波長）所檢測出之偏振 旋轉成分之光強度與針對其他波長（第2波長）所檢測出之 偏振旋轉成分之光強度的強度比，會依L/s圖案12之間 距P而變化。 在本實施形態，將表示針對基準波長所檢測出之光強 度與針對各波長所檢測出之光強度的強度比、與L/s圖 案之間距的對應關係表，設於測定系統6。此種表，係預 先使用本實施形態之裝置實際測定例如在接近理想狀態之 曝光條件下高精度形成於光阻之L/ s圖案之間距而獲得。 200907292 求得針對基準波長所檢測出之光 出之光強度的強度比、與s 或亦可藉由光學模擬預先 強度與針對各波長所檢測 圖案之間距的關係。 /、次，參照圖6所示之流程圖，說明以 之間距測定装置來測定測定對象之L/s圖案12之間距p 的方法。百先’至少㈣2個波長之光並照射於Μ圖 案照射步驟Sl〇1)。具體而言，例如藉由將波長選擇過 /慮器2更換為波長選擇過潘·玛9 n +、士 E # 、伴迥/愿益2a或波長選擇過濾器2b， 以切換i線u =365nm)之光、h線（λ，⑽）之光或§線以 之光並照射於L/s圖# 12。或例如藉由將光源 之水銀燈1切換為KrF準分子雷射光源la，以切換^線（又 = 365nm)之光、波長又為248nm之光並照射於l/s圖案 12 °A configuration diagram of the distance measuring device according to the first embodiment of the present invention. Figure 2 is an overview of the first! In the embodiment, the configuration of the W pattern of the measurement target is measured, and (4) shows a plan view, and (b) shows a cross-sectional view along the line direction of the line (4). Further, in Fig. 2', for the sake of easy understanding, only the rectangular portion of the L/8 ® Ansan s <s pattern of the measurement target is shown. Referring to Fig. 2, the L / S pattern 12 formed on the surface of the λ Υ + surface of the object j is a slanted line m _ "a deep in Fig. 2 (a). The line portion ") 1 2a is constituted by a recessed portion (hereinafter referred to as "space portion") 12b of the blank portion in Fig. 2(a). The line portion i2a and the *compartment portion 2b are linearly extended in the direction of 45 degrees from the +X direction and the +Y direction. 200907292 In other words, the longitudinal direction of the L/S pattern 12 is a direction 45 degrees from the +χ direction and the +γ direction. The direction between the L/S patterns 12 is 45 degrees from the +χ direction and the -Υ direction. Further, as shown in Fig. 2(b), the width of the line portion 12a and the width dimension Wa are equal to the width of the space portion m. Therefore, if the width dimension Wb of the length of the length between the line portions 12a and the length of the space between the space portions (2) is represented by w, the distance p between the L/S patterns 1 2 is 2 w. Referring to Fig. 1, a distance measuring device according to a first embodiment includes a light source such as a K-silver lamp 1. The light from the mercury lamp i is incident on the wavelength selective reducer 2 through an optical system such as an elliptical mirror or a collimator lens (not shown). The wavelength selective filter 2 has a characteristic of selectively transmitting light of the i-line U = 365 nm). The wavelength selection filter 2 can be detachably mounted on the optical path, and can be replaced with other wavelength selective filters 2a, 2b having different characteristics. Specifically, the wavelength selective filter H 2a has a characteristic of selectively transmitting light such as h, ^u = 4 () 5 nm), and the wavelength selective filter 2b has selective transmission of light such as _λ = 43 - characteristic. The light having the wavelength selected by the wavelength selective filter "a or the hole is incident on the polarizing element 3. The X-silver lamp 1 is configured to be switchable to, for example, a xenon excimer laser light source 4 that supplies light having a wavelength of "km". . When the KrF excimer is used: when the light source U is used as the light source, the optical system from the KrF excimer laser light source, the light source, and the like, is incident on the polarizing element 3. The polarizing element 3 has, for example, a picture with a figure! The light is selectively passed through (4) # η 1 polarization. ! The linearly polarized 200907292 light of the transpolarizing element 3 is obliquely incident on the L/s pattern 12 formed along the surface of the XY plane of the object 11. Here, the wavelength of light incident on the L/S pattern 12 (λ = 248, 3 65, 405, 436 nm in the present embodiment) is set to a longer wavelength. Further, the incident direction of the light toward the l/S pattern 12 (in the χ direction in the present embodiment) is set to be a direction in which both the distance direction and the longitudinal direction of the L/S pattern 12 intersect. Further, the polarization direction of the light incident on the L/S pattern 12 (in the γ direction perpendicular to the paper surface of FIG. 1 in the present embodiment) is also set to intersect with the distance direction and the long side direction between the L/s pattern 12. direction. Thus, the light source Ula), the wavelength selective filter 2 (2a, 2b), and the polarizing element 3 constitute an illumination system for switching the light in the linearly polarized state between the four wavelengths and irradiating the L/s pattern 12. The light from the irradiation system (1 to 3) is irradiated, and the diffracted light reflected by the L/s pattern 12 is incident on the light detecting element (polarizing element) 4 satisfying the orthogonal polarization condition. The light detecting element 4 has a characteristic of selectively passing light having a polarization direction orthogonal to the polarization direction of the incident light of the L/s pattern 12. The secondary diffracted light passing through the predetermined linear polarization state of the light detecting element 4 reaches a photodetector (light receiving element) 5 such as a CCD. The light intensity of the zero-order diffracted light incident is detected by the photodetector 5. In this manner, the photodetecting element 4 and the photodetector 5 are configured to detect the polarization direction orthogonal to the polarization direction of the incident light toward the pattern 12 at the order of the diffraction pattern of the pattern 12 reflected. Secondary diffracted light detection system. The light detection H 5 output is supplied to the system as a signal processing 200907292 P 疋 system 6. In the measurement system 6, as will be described later, the root system (10) is detected for the first wavelength. The intensity of the light of the secondary diffracted light The intensity of the light intensity of the zero-order diffracted light detected by the third length is measured (measured) by the distance ρ between the L/S patterns 12. In addition, in the detection system (4, 5), only the bismuth (polarization rotation component) having a polarization direction orthogonal to the polarization direction of the person's light emitted toward the / /S pattern 12 is detected, and the impurity is removed. The reason for the news component. Actually, although the light-emitting person photodetector 5 having the same polarization direction (vibration surface) as the polarization direction of the incident light toward the L/s pattern 12 cannot be completely blocked, the allowable manufacturing error due to the light-detecting element 4 is tolerated (tolerance) ) and the light of the shot. In the distance measuring device of the present embodiment, the wavelength of the light irradiated to the l/$ pattern 12 is switched between four wavelengths λ = 248 nm, λ = 365 nm, λ = 4 〇 5 nm A = 436 nm, and is detected for each wavelength. The light intensity of the primary diffracted light (polarization rotating component) having a polarization direction orthogonal to the polarization direction of the incident light of the pattern 12 is emitted. In this case, when the wavelength of 248 nm is set as the reference wavelength, the light intensity of the polarization rotation component detected for the reference wavelength (the first wavelength) and the polarization rotation component detected for the other wavelength (the second wavelength) are The intensity ratio of the light intensity varies depending on the distance P between the L/s patterns 12. In the present embodiment, a correspondence table showing the intensity ratio between the light intensity detected for the reference wavelength and the light intensity detected for each wavelength and the distance between the L/s patterns is provided in the measurement system 6. Such a watch is obtained by, for example, actually measuring the distance between the L/s patterns of the photoresist which is formed with high precision under exposure conditions close to an ideal state, using the apparatus of the present embodiment. 200907292 Find the intensity ratio of the intensity of the light detected by the reference wavelength, and s or the relationship between the optical intensity and the distance between the patterns detected for each wavelength. Next, a method of measuring the distance p between the L/s patterns 12 of the measurement target by the distance measuring device will be described with reference to a flowchart shown in FIG. 6. The first light is at least (four) light of two wavelengths and is irradiated to the 照射 pattern irradiation step S1〇1). Specifically, for example, by changing the wavelength selection filter 2 to the wavelength selection Pan Ma 9 n +, Shi E # , 迥 愿 / 2 2 or the wavelength selection filter 2b, the i line u = Light of 365 nm), light of h line (λ, (10)) or light of § line is irradiated to L/s diagram #12. Or, for example, by switching the mercury lamp 1 of the light source to the KrF excimer laser light source la, to switch the light of the line (again = 365 nm), the light having a wavelength of 248 nm, and irradiate the l/s pattern 12 °.
使藉由波長選擇過濾器2,2a或2b選擇波長之光，或 透過擴束器等光學系統之來自KrF準分子雷射光源u之 光射入偏振元件3。照射L/S圖案12之光’藉由通過偏 振元件3，成為於與L/S圖案12之間距方向及長邊方向 兩者父叉之方向具有偏振方向的直線偏振狀態。 將以此方式透過照射系統（1〜3)所獲得之直線偏振狀態 之光，沿L/ S圖案12之間距方向及與長邊方向兩者交又 之方向照射於L/S圖案12。 其次，於光檢測器5檢測出經由照射步驟s丨〇丨並在乙 /S圖案12反射而通過檢光元件4之〇次繞射光（檢測步 驟S102)。在檢測步驟S102，藉由透過檢光元件4，檢測 11 200907292 出具有與朝L/S圖案12之入射光之偏振方向正交 方向的〇次繞射光。 接著，於檢測步驟S102，根據作為第】波長（例如， 波長Λ=248ηιη)所檢測出之〇次繞射光之光強度與作為第2 波長（例如，波長λ =365nm)所檢測出之〇次繞射光之光強 度的強度比’以測定系統6測定L/s圖案12之間距p(測 定步驟S1G3)。光檢測器5之輸出供應至測定系統6。 此處，說明於測定步驟Sl〇3測定L/s圖案12之間 距：的方法。首先’設定例如第i波長作為基準波長。於 測疋系、統6㈣先設$，表示針對基準波長所檢測出之光 強度與針對其他各波長所檢測&之光強度的強度比、與^ /S圖案之間距p的對應關係表。接著，根據該表，從強 度比與第2波長值求出s圖案12之間距p。 以下表1表示強度比與圖案之間距之對應關係 表的例子。此時，使用波長人=24^瓜之光作為基準波長（第 1波長）。表1，係將在接近理想狀態之曝光條件下高精度 j形成於光阻之s圖案（取樣圖案）之間距ps，使用第工 實施形態之裝置實際測定所獲得。 (表1) -——~ -- --Psj=9〇nm Ps=ll〇nm —65nm 0.58 0.62 一5nm _____〇31 0.34 —6nm ------ ____0.21 0.22 12 200907292 表1，係表示各第2波長λ對取樣圖案之不同間距Light of a wavelength selected by the wavelength selective filter 2, 2a or 2b, or light from a KrF excimer laser light source u transmitted through an optical system such as a beam expander is incident on the polarizing element 3. The light illuminating the L/S pattern 12 is a linearly polarized state having a polarization direction in the direction of the parent and the longitudinal direction of the L/S pattern 12 by the polarizing element 3. The light of the linearly polarized state obtained by the irradiation systems (1 to 3) in this manner is irradiated to the L/S pattern 12 in the direction in which the distance between the L/S pattern 12 and the longitudinal direction intersect. Next, the photodetector 5 detects the sub-refracted light that has passed through the photodetecting element 4 via the irradiation step s and is reflected by the B/S pattern 12 (detection step S102). In the detecting step S102, by detecting the light detecting element 4, it is detected that 11 200907292 has the order diffracted light having a direction orthogonal to the polarization direction of the incident light toward the L/S pattern 12. Next, in the detecting step S102, the light intensity of the primary diffracted light detected as the λth wavelength (for example, the wavelength Λ=248 ηηη) and the detected intensity as the second wavelength (for example, the wavelength λ = 365 nm) are detected. The intensity ratio of the light intensity of the diffracted light is measured by the measurement system 6 to determine the distance p between the L/s patterns 12 (measurement step S1G3). The output of the photodetector 5 is supplied to the measurement system 6. Here, a method of measuring the distance between the L/s patterns 12 in the measurement step S103 will be described. First, for example, the i-th wavelength is set as the reference wavelength. In the measurement system, the system 6 (4) first sets $, which indicates a correspondence table between the intensity ratio of the light intensity detected by the reference wavelength and the light intensity detected for the other wavelengths, and the distance p between the ^ /S patterns. Next, based on the table, the distance p between the s patterns 12 is obtained from the intensity ratio and the second wavelength value. Table 1 below shows an example of a table of correspondence between the intensity ratio and the distance between the patterns. At this time, light of a wavelength of 24 = melon is used as a reference wavelength (first wavelength). In Table 1, the high-precision j is formed in the s pattern (sampling pattern) between the photoresists under the exposure conditions close to the ideal state, and is obtained by actual measurement using the apparatus of the first embodiment. (Table 1) -——~ -- --Psj=9〇nm Ps=ll〇nm—65nm 0.58 0.62 A 5nm _____〇31 0.34 —6nm ------ ____0.21 0.22 12 200907292 Table 1, Indicates the different spacing of each second wavelength λ to the sampling pattern
Ps(Ps = 9〇nm，Ps = 110nm)所獲得之強度比。根據表}所示， 例如將波長；I =365nm之光作為第2波長照射於s圖案 12時所獲得之強度比為〇_58之情形，L/s圖案i2之間距 P測定為90nm。或者，例如將波長A=365nm之光作為第 2波長照射於L/ S圖案12時所獲得之強度比為〇·62之情 形，L/ S圖案12之間距ρ測定為！ 1〇nm。或者，例如= 波長；l=436nm之光作為第2波長照射於L/s圖案12時 所獲得之強度比為0.21之情形，L/s圖案12之間距p測 定為90nm。 此處，針對具有不同間距之取樣圖案，將作為第2波 長照射之光之波長、與第丨波長之強度與第2波長之強度 之強度比之關係的圖表，表示於圖7。於圖7，縱軸表示 將針對基準波長；l =248nm之波長所檢測出之偏振旋轉成 光強度規格化為1時的光強度。橫轴表示照射於取樣 4 W案之L/S圖案之光的波長（nm)。又，圖SG1表示間距 為9〇nm之取樣圖案的情形，圖表G2表示間距為11〇nm 之取樣圖案的情形。 以下’依照具體之數值例，驗證第1實施形態之作用 政果。圖3係表示形成於光阻之L/S圖案之起伏（粗糙度） 的示思圖如圖3所示’於光阻面内L/ S圖案12具有粗 I度時，L/ S圖案12之粗糙度，例如藉由線寬為Wa之 、’泉°卩12a之叙糙度振幅Am與粗糙度周期pr來模型化並附 予特徵。 13 200907292 在第1數值例，關於線部12a之線寬Wa《55nm且間 距P為1 1 〇nm之L/S圖奢. 圃柔12，粗糙度周期Pr為li〇nm， 且粗糖度振幅Am為〇nm，2.5nm，5nm，7 — _時， 错由模擬求出在檢測系統（4,5)針對各波長所檢^之偏振 紋轉成分的光強度。圖4，係表 承表不於第1數值例中就不同 粗I度振幅之L/S圖案針對夂味F , 轉對各波長之光所㈣Λ之偏振 旋轉成分的光強度。 :::，縱軸表示將以基準波長又，之波長所檢 f出之偏振旋轉成分之光強度規格化…的光強度。橫 耵於L/S圖案12之光的波長(nm)。又，al表示 粗糖度振幅Am為〇nm之情报 。_ nm <滑形，a2表示粗糙度振幅Am為 2.5nm之情形，a3表 ·、、、 一 和1厌搌巾田Am為5nm之情形，a4 表不粗糖度振幅Am為7.5nm之愔裉，以本-Λ , m之滑形，a5表不粗糙度振幅 為10nm之情形。 此外，在圖4，為容易理解本實施形態之作用效果， 將就各波長所檢測出之偏振旋轉成分的光強度以小點表 不’並將各小點間以直線連結。目4之表示方法，於第2 數值例之圖5亦相同。參照圖4，在f i數值例可知，即 使粗糙度振幅Am| “至1〇nm間變化，就基準波長所 檢：出之光強度與就各波長所檢測出之光強度的強度比幾 一有Sl動亦即，在第1數值例，可根據就基準波長所 檢測出之光強度與就各波長所檢測出之光強度的強度比， 在=叉貫質L/ S圖案12之粗糙度振幅的影響之情況下， 測疋L/S圖案12之間距p。 200907292 f第2數值例’關於線部⑵之線寬％為^且間 距：、' 11〇nm<L/S圖案12,粗糙度周期卜為22〇n 1數值例之2倍周期）且粗糙度振幅Am為〇nm 2 Ί , um，2_5nm，5nm, .⑽，nm時，藉由模擬求出檢測系統（〇針對各波 所檢測出之偏振旋轉成分的光強度。8 5，係表示於第2 數值例令就不同粗趟度振幅之L/s圖案針對各波長 所檢測出之偏振旋轉成分的光強度。 參照圖5,可知在第2數值例亦與第i數值例相同， 即使粗糙度振幅Am在〇nm i 1Gnm間變化，針對基準波 長所檢測出之光強度與針料波長所檢測出之㈣度的強 度比幾乎沒有變動。此外，與第！數值例的情形不同，針 對基準波長所檢測出之光強度與針對365nm波長 之光強度的強度比雖有些微的變動’但其變動的幅度與強 度比相比0_6)為非常小。以此方式，即使於第2數值例， 亦可根據針對基準波長所檢測出之光強度與針對各波長所 檢測出之光強度的強度比，在不受實質L/s圖案u ^粗 糙度振幅的影響之情況下，來測定L/ s圖案12之間距p。 在圖5，為使圖面明瞭化，雖省略粗糙度振幅八瓜為 2.5nm時之強度比及7.5nm時之強度比的表示，但此等強 度比可確認為在粗糙度振幅Am為〇nm時之強度比與【 時之強度比之間。又，比較圖4與圖5可知，即使粗糙度 周期Pr在llOnm與220nm間變化，但針對基準波長所檢 測出之光強度與針對各波長所檢測出之光強度的強度比幾 乎沒變動。如此可知，在本實施形態，測定L/ s圖案12 15 200907292 之間距P *受實質L/s圖案12之粗链度振幅及粗趟度周 期的影響。 & 如上所述，在本實施形態，由於檢測在s圖案反 射之〇次繞射光，因此能使用較長波長之光作為朝 圖案12之照射光。其結I，在本實施形態，與為滿足布 拉格定律之條件而使用短波長之光的習知技術相比，能實 現簡單構成之低價裝置。又，在本實施形態，由於使用較 長波長之光作為朝L/S圖案12之照射光，因此，在測定 开/成於光阻之L/ S圖案之間距時，沒有使光阻感光之危 進一步，在本實施形態’將朝L/s圖案12之照射光 之波長在4個波長間切換，根據針對又=248nm之基準波 長（第1波長）所檢測出之〇次繞射光之光強度與針對又…“ 4〇5nm，^㈣之各波長（第2波長）所檢測出之〇次繞射光 之光強度的強度比’來測定L/s圖案12之間距卜其結 果，如上述’在本實施形態，能不受實質L/s圖案Μ之 粗糙度的影響，來高精度測定L/s圖案12之間距卜 此外，在上述實施形態，將朝L/S圖案12之照射光 長在4個波長間切換。然而，並不限定於此，藉由將 月L:S圖案之照射光之波長在至少2個波長間切換，能 個針對第1波長所檢測出之。次繞射光之光強 ^^ 波長所檢測出之〇次繞射光之光強度的強度 進而’能根據此至少、】個之強度比， 案之間距。 / w 16 200907292 又’在上述實施形態，將照射於L/s圖案1 2之光之 波長在 4 個波長 λ =248nm, λ =365nm, λ =4〇5nm，入 =436nm間切換。然而，不限定於此，能在自較長波長適 當選擇至少2個波長之間，切換朝L// s圖案之照射光的 波長。 此外，亦能將照射於L/ S圖案12之光之波長，設定 成自L/S圖案12僅會產生〇次繞射光之反射光的波長。 其原因在於，若自L/s圖案12與〇次繞射光同時產生高 人、·堯射光，則此咼次繞射光成為雜訊成分，依存於[/ s 圖案12之間距P之所需特性可能無法再從〇次繞射光之 強度找出的緣故。相對於此’若將朝L/S圖案12之照射 光之波長，設定成自L/S圖案12僅會產生〇次繞射光之 射光的波長，則來自L/S圖案12之0次繞射光的強度 成為最大，L/ S圖案12之間距p的測定精度亦會提昇。 又，在上述實施形態，朝L/ S圖案12之光之入射方 ( 向，叹疋成於圖案面（XY平面）中L/S圖案12之間距方向 長邊方向兩者成45度的方向。然而，並不限定於此， 朝L/S圖案12之光之入射方向亦能設定成與圖案 之間距方向及長邊方向兩者交叉之既定方向。其原因在 於右朝L/S圖案12之光之入射方向與圖案12之 距方向或長邊方向一致，則檢測系統(4,5)所檢测出之來 L/ S圖案12之偏振旋轉成分的強度會變成q的緣故。 :對於此’若將朝L/S圖案12之光之入射方向，設定成 ” L/S圖案12之間距方向及長邊方向兩者成45度的方 17 200907292 向，則來自L/s圖案12之偏振旋轉成分之強度成為最大， L/ S圖案12之間距p的測定精度亦會提昇。 又，在上述實施形態，雖以線部12a之寬度尺寸 與空間部i2b之寬度尺寸机為相等之L/s圖案i2作為 測定對象，但並不限定於此，亦能將線部之寬度尺寸與空 間部之寬度尺寸相互*同之L八圖案作為測定對象。 又，在上述實施形態，偏振元件3設置於照射系統， 檢光元件4設置於檢測系統。然而，並不限定於此，亦可 省略偏振元件3或檢光元件4,或偏振元件3與檢光元件 4兩者。檢測系統檢測出之〇次繞射光之雜訊成分小時， 即使省略偏振元件3或檢光元件4之構成，亦能高精度地 測定L/S圖案12之間距P。 (第2實施形態） 其次，說明第2實施形態之表面測定裝置及使用該裝 置之表面檢查方法。首先，說明表面檢查裝置之構成。 如圖8所示，於表面檢查裝置丨0，具備支撐被檢測晶 圓20之載台sT、對準系統AL、照明系統13、受光系統14、 控制運算裝置15、影像顯示裝置16、及輸入器17等。 被檢測晶圓20，係其最上層為已完成曝光及顯影之光 阻膜的半導體晶圓，並於表面形成有L/S圖案12。被檢 力J曰曰曰圓20藉由未圖示之搬送系統自未圖示之晶圓輸送盒 或顯影裂置搬送，並固定保持於載台ST上。該被檢測晶 圓20 ’藉由載台ST，能以上面中心之法線1A為旋轉轴旋 丰專°該旋轉中之被檢測晶圓20之旋轉位置，由設置於其 18 200907292 外緣之缺口或定向平面等之形狀，藉由對準系统al來檢 藉由該對準系統AL與載纟ST，被檢測晶圓之旋 轉位置設定於適合表面檢查的位置。 照明系統13係依光源31、波長選擇部32、導光光纖 33、偏振過濾器’ 34、及凹面反射鏡35之順序配置之偏心 光學系統。光源31係水銀燈或金屬南素燈等之放電光源， 波長選擇部32係切換自該光源31朝導光光纖33之光之 波長的機構。 波長選擇部32’具備：準直透鏡25，用以將自光源 來之光轉換為平行光朿；轉# m，用以對該平行光束選 擇丨插入不同透射波長區域之複數個波長選擇過濾器F1， F2’ F3’ F4, F5’ F6 ;聚光透鏡26，用以將通過轉台12b之 平订光束朝導光光纖33之入射端聚光；以及馬達23c，用 =使轉台12b旋轉。若驅動該馬達23c，則會切換朝導光 光纖33之入射端射入之光的波長。此外，關於光源31之 亮線光譜與波長選擇過遽器F1，F2, F3, F4, F5之透射波長 區域，留待後述。 朝導光光纖33之入射端射入之光，在該導光光纖33 内部傳導，並從該射出端射出。肖光，藉由配置於射出端 附近之偏振過濾器34轉換成直線偏振後，透過凹面反射 鏡35，自傾斜方向照明被檢測晶圓2〇之大致全面。該凹 面反射鏡35之射出光軸〇1，係通過載台ST之中心，並 相對於載台ST之法線丨a傾斜既定角度θ。 該凹面反射鏡35,係以球面之内側作為反射面之反射 19 200907292 鏡，其前側焦點與導光光纖33之射出端大致一致，其後 側焦點與被檢測晶圓20之表面大致一致。藉由該凹面反 射鏡35，被檢測晶圓2〇之全面，被遠心之直線偏光u照 明。朝被檢測晶圓20上之各點之各直線偏光u之主光線（行 進方向），與凹面反射鏡35之射出光軸〇1大致平行。上 述偏振過濾器34之透射軸的方位預先設定為，此等直線 偏光L1之偏振方向相對於被檢測晶圓2〇之表面為p偏振。 如此，照明系統U，藉由將波長選擇過濾器F1，F2, F3, F4, F5, F6選擇性插入，發揮切換至少2個波長之光並照 射於L/ S圖案12之照射系統的功能。此處，將切換並照 射於L/S圖案12之2個波長稱為第丨波長（基準波長）及 弟2波長。 文光系統14，係依凹面反射鏡36、偏振過濾器38、 成像透鏡37、及攝影元件39順序配置之偏心光學系統。 凹面反射鏡36，係與照明系統13之凹面反射鏡35相同之 反射鏡，其入射光軸〇2 ,係與法線1A及凹面反射鏡35 之射出光軸οι在同一平面上，且入射光轴〇2與法線ia 形成之角度係與射出光軸〇1與法線丨A形成之角度相同為 Θ。是以，來自被檢測晶圓2〇之正反射光（〇次繞射光， 係沿凹面反射鏡36之入射光軸02行進。凹面反射鏡36， 將其正反射光L2反射並導向偏振過濾器38，並與成像透 鏡37協同動作而於攝影元件39之攝影面上形成被檢測晶 圓20之反射像。 此處’偏振過滤器38之透射軸的方位，設定成與照明 20 200907292 系統1 3内之偏振過濾器34之透射軸正交（正交偏振（cr〇ss_ nicol)之狀態）。是以，通過偏振過濾器38之直線偏光L4, 在正反射光L2中，相當於與直線偏光之偏振方位正交 之偏振成分。該直線偏光L4之強度，決定上述反射像之 強度。The intensity ratio obtained by Ps (Ps = 9 〇 nm, Ps = 110 nm). As shown in the table}, for example, when the intensity ratio of the wavelength; I = 365 nm as the second wavelength is irradiated to the s pattern 12 is 〇_58, the distance P between the L/s pattern i2 is measured to be 90 nm. Alternatively, for example, when the light having the wavelength A = 365 nm is irradiated to the L/S pattern 12 as the second wavelength, the intensity ratio obtained is 〇·62, and the distance ρ between the L/S patterns 12 is measured as ! 1〇nm. Alternatively, for example, = wavelength; l = 436 nm light is obtained as the second wavelength when the intensity ratio obtained by irradiating the L/s pattern 12 is 0.21, and the distance p between the L/s patterns 12 is determined to be 90 nm. Here, a graph showing the relationship between the wavelength of the light irradiated with the second wavelength and the intensity of the intensity of the second wavelength and the intensity of the second wavelength is shown in Fig. 7 for the sampling patterns having different pitches. In Fig. 7, the vertical axis indicates the light intensity when the polarization detected by the wavelength of the reference wavelength; l = 248 nm is normalized to 1 when the light intensity is normalized. The horizontal axis represents the wavelength (nm) of light irradiated to the L/S pattern of the sampled sample. Further, Fig. SG1 shows a case of a sampling pattern having a pitch of 9 〇 nm, and Fig. G2 shows a case of a sampling pattern having a pitch of 11 〇 nm. The following is based on a specific numerical example to verify the effect of the first embodiment. 3 is a view showing the undulation (roughness) of the L/S pattern formed on the photoresist. As shown in FIG. 3, when the L/S pattern 12 has a thickness of 1 degree in the photoresist plane, the L/S pattern 12 is shown. The roughness is modeled and characterized by, for example, the roughness amplitude Am of the spring width W12a and the roughness period pr. 13 200907292 In the first numerical example, the line width Wa of the line portion 12a is "55 nm and the pitch P is 1 1 〇nm L/S figure luxury. The softness period 12, the roughness period Pr is li〇nm, and the coarse sugar amplitude When Am is 〇nm, 2.5nm, 5nm, 7__, the light intensity of the polarization-switching component detected for each wavelength in the detection system (4, 5) is obtained by simulation. Fig. 4 is a graph showing the light intensity of the polarization rotation component of the (4) 转 of the light of each wavelength of the L/S pattern of the coarse I degree amplitude in the first numerical example. :::, the vertical axis indicates the light intensity normalized by the light intensity of the polarization rotation component detected by the wavelength of the reference wavelength. The wavelength (nm) of the light that traverses the L/S pattern 12. Further, al represents the information that the coarse sugar amplitude Am is 〇nm. _ nm <slip shape, a2 indicates a case where the roughness amplitude Am is 2.5 nm, a3, ·,, and 1 are not 5 nm, and a4 indicates a coarse sugar amplitude Am of 7.5 nm.裉, with the sliding shape of Ben-Λ, m, a5 shows the case where the roughness amplitude is 10 nm. Further, in Fig. 4, in order to facilitate the understanding of the effects of the present embodiment, the light intensity of the polarization rotation component detected for each wavelength is indicated by a small dot and the small dots are connected by a straight line. The method of expressing the object 4 is the same as that of Fig. 5 of the second numerical example. Referring to Fig. 4, in the numerical example of fi, even if the roughness amplitude Am| "changes to 1 〇 nm, the reference wavelength is detected: the intensity of the light emitted is different from the intensity of the light detected for each wavelength. In the first numerical example, the roughness amplitude of the cross-cut L/S pattern 12 can be obtained from the intensity ratio of the light intensity detected with respect to the reference wavelength and the intensity of the light detected for each wavelength. In the case of the influence, the distance between the L/S patterns 12 is measured. 200907292 f The second numerical example '% of the line width of the line portion (2) is ^ and the pitch: '11 〇 nm<L/S pattern 12, rough The degree period is 22 times n 2 times the numerical value of the numerical example) and the roughness amplitude Am is 〇nm 2 Ί , um, 2_5 nm, 5 nm, (10), nm, and the detection system is obtained by simulation (〇 for each wave) The light intensity of the detected polarization rotation component is shown by the second numerical example, and the light intensity of the polarization rotation component detected for each wavelength with respect to the L/s pattern of different roughness amplitudes is shown. It can be seen that the second numerical example is the same as the i-th numerical example, and even if the roughness amplitude Am changes between 〇nm i 1Gnm, The intensity ratio of the light intensity detected by the quasi-wavelength and the (four) degree detected by the wavelength of the needle material hardly change. In addition, unlike the case of the numerical example, the light intensity detected for the reference wavelength and the wavelength for 365 nm are used. The intensity ratio of the light intensity is slightly changed 'but the amplitude of the variation is very small compared to the intensity ratio 0_6. In this way, even in the second numerical example, the light intensity detected for the reference wavelength can be used. The intensity ratio of the light intensity detected for each wavelength is measured without being affected by the amplitude of the substantial L/s pattern u ^ roughness, and the distance p between the L/s patterns 12 is measured. The figure is clear, and although the intensity ratio of the roughness amplitude of the quarantine at 2.5 nm and the intensity ratio at 7.5 nm are omitted, the intensity ratio can be confirmed as the intensity ratio when the roughness amplitude Am is 〇nm. [Between the intensity ratios of the time. In addition, comparing FIG. 4 with FIG. 5, even if the roughness period Pr varies between llOnm and 220 nm, the light intensity detected for the reference wavelength and the light intensity detected for each wavelength The intensity ratio has hardly changed As can be seen, in the present embodiment, it is determined that the distance P* between the L/s pattern 12 15 200907292 is affected by the coarse chain amplitude and the roughness period of the substantial L/s pattern 12. & As described above, In the embodiment, since the diffracted light reflected by the s pattern is detected, light having a longer wavelength can be used as the illumination light toward the pattern 12. In the present embodiment, in the present embodiment, the condition is short to satisfy the conditions of the Bragg's law. Compared with the conventional technique of wavelength light, a low-cost device having a simple configuration can be realized. Further, in the present embodiment, since light having a longer wavelength is used as the illumination light toward the L/S pattern 12, the measurement is turned on/ In the case of the distance between the L/S patterns of the photoresist, there is no risk of the photoresist being sensitive. In the present embodiment, the wavelength of the illumination light to the L/s pattern 12 is switched between four wavelengths, according to The light intensity of the primary diffracted light detected by the reference wavelength of 248 nm (the first wavelength) and the light intensity of the secondary diffracted light detected for each wavelength (the second wavelength) of "4 〇 5 nm, ^ (4)" Intensity ratio 'to determine the distance between the L/s pattern 12 As a result, as described above, in the present embodiment, it is possible to accurately measure the distance between the L/s patterns 12 without being affected by the roughness of the substantially L/s pattern ,, and in the above embodiment, the pattern toward the L/S The illumination length of 12 is switched between 4 wavelengths. However, the present invention is not limited thereto, and the wavelength of the illumination light of the month L:S pattern is switched between at least two wavelengths, and can be detected for the first wavelength. The intensity of the secondary diffracted light ^^ The intensity of the intensity of the diffracted light detected by the wavelength, and then the intensity ratio of the at least one, according to the distance between the cases. / w 16 200907292 In the above embodiment, the wavelength of light irradiated to the L/s pattern 1 2 is switched between four wavelengths λ = 248 nm, λ = 365 nm, λ = 4 〇 5 nm, and input = 436 nm. However, the present invention is not limited to this, and the wavelength of the illumination light toward the L//s pattern can be switched between at least two wavelengths appropriately selected from longer wavelengths. Further, the wavelength of the light irradiated to the L/S pattern 12 can be set to a wavelength at which only the reflected light of the sub-diffracted light is generated from the L/S pattern 12. The reason for this is that if the L/s pattern 12 and the sub-diffracted light simultaneously generate high-intensity and radiant light, the sub-circumferential light becomes a noise component, depending on the desired characteristics of the distance P between the [/ s patterns 12 It may not be possible to find out the intensity of the diffracted light. On the other hand, if the wavelength of the light to be irradiated toward the L/S pattern 12 is set to a wavelength at which only the light of the secondary diffracted light is generated from the L/S pattern 12, the 0th-order diffracted light from the L/S pattern 12 is set. The intensity is maximized, and the measurement accuracy of the distance p between the L/S patterns 12 is also improved. Further, in the above-described embodiment, the incident direction of the light of the L/S pattern 12 (the direction in which the sigh is formed in the pattern surface (XY plane) is 45 degrees in the longitudinal direction of the L/S pattern 12; However, the present invention is not limited thereto, and the incident direction of the light toward the L/S pattern 12 can be set to a predetermined direction intersecting both the direction of the pattern and the direction of the longitudinal direction. The reason is that the rightward L/S pattern 12 When the incident direction of the light coincides with the distance direction or the longitudinal direction of the pattern 12, the intensity of the polarization rotation component of the L/S pattern 12 detected by the detection system (4, 5) becomes q. If the incident direction of the light toward the L/S pattern 12 is set to "the direction of the distance between the L/S pattern 12 and the longitudinal direction of the square 17 200907292 direction, then from the L/s pattern 12 The intensity of the polarization rotation component is maximized, and the measurement accuracy of the distance p between the L/S patterns 12 is also improved. Further, in the above embodiment, the width dimension of the line portion 12a and the width dimension of the space portion i2b are equal to each other. The /s pattern i2 is a measurement target, but is not limited thereto, and the width dimension of the line portion can also be Further, in the above embodiment, the polarizing element 3 is provided in the irradiation system, and the light detecting element 4 is provided in the detection system. However, the present invention is not limited thereto. The polarizing element 3 or the light detecting element 4, or both the polarizing element 3 and the light detecting element 4 are omitted. When the noise component of the secondary diffracted light detected by the detecting system is small, even if the configuration of the polarizing element 3 or the light detecting element 4 is omitted, The distance P between the L/S patterns 12 can also be measured with high precision. (Second Embodiment) Next, a surface measuring device according to the second embodiment and a surface inspecting method using the same will be described. First, the configuration of the surface inspecting device will be described. As shown in FIG. 8, the surface inspection apparatus 丨0 includes a stage sT for supporting the wafer to be detected 20, an alignment system AL, an illumination system 13, a light receiving system 14, a control arithmetic unit 15, an image display unit 16, and an input. The wafer to be inspected is a semiconductor wafer whose uppermost layer is a photoresist film which has been exposed and developed, and an L/S pattern 12 is formed on the surface. Not shown The delivery system is transported from a wafer transfer cassette (not shown) or a development slit, and is fixedly held on the stage ST. The detected wafer 20' can be rotated by the upper center normal line 1A by the stage ST. The rotation position of the detected wafer 20 in the rotation is determined by the alignment system a1 by the alignment system a1 by the shape of the notch or the orientation plane disposed on the outer edge of the 18 200907292. At the loading point ST, the rotational position of the detected wafer is set at a position suitable for surface inspection. The illumination system 13 is in the order of the light source 31, the wavelength selecting unit 32, the light guiding fiber 33, the polarization filter '34, and the concave mirror 35. Eccentric optical system configured. The light source 31 is a discharge light source such as a mercury lamp or a metal lamp, and the wavelength selecting unit 32 is a mechanism for switching the wavelength of light from the light source 31 toward the light guiding fiber 33. The wavelength selecting portion 32' is provided with: a collimating lens 25 for converting light from the light source into a parallel pupil; and a #m for inserting the parallel beam selection into a plurality of wavelength selective filters of different transmission wavelength regions F1, F2' F3' F4, F5' F6; a collecting lens 26 for collecting the flat beam passing through the turntable 12b toward the incident end of the light guiding fiber 33; and a motor 23c for rotating the turntable 12b. When the motor 23c is driven, the wavelength of light incident on the incident end of the light guiding fiber 33 is switched. Further, the transmission wavelength region of the bright line spectrum of the light source 31 and the wavelength selection filters F1, F2, F3, F4, and F5 will be described later. Light incident on the incident end of the light guiding fiber 33 is conducted inside the light guiding fiber 33 and is emitted from the emitting end. The light is converted into linear polarization by the polarization filter 34 disposed near the emission end, and then transmitted through the concave mirror 35 to illuminate the detected wafer 2 from the oblique direction. The optical axis 〇1 of the concave reflecting mirror 35 passes through the center of the stage ST and is inclined by a predetermined angle θ with respect to the normal line 丨a of the stage ST. The concave reflecting mirror 35 is a reflection of the reflecting surface on the inner side of the spherical surface. The front side focus is substantially coincident with the emitting end of the light guiding fiber 33, and the rear side focus substantially coincides with the surface of the wafer to be inspected. With the concave reflecting mirror 35, the entire surface of the wafer 2 to be detected is illuminated by the telecentric linear polarizing light u. The chief ray (the traveling direction) of each of the linearly polarized lights u at the respective points on the detected wafer 20 is substantially parallel to the exiting optical axis 〇1 of the concave reflecting mirror 35. The orientation of the transmission axis of the polarization filter 34 is set such that the polarization direction of the linear polarization L1 is p-polarized with respect to the surface of the wafer 2 to be detected. In this manner, the illumination system U selectively inserts the wavelength selective filters F1, F2, F3, F4, F5, and F6, and functions to switch the light of at least two wavelengths and illuminate the illumination system of the L/S pattern 12. Here, the two wavelengths that are switched and irradiated to the L/S pattern 12 are referred to as a second wavelength (reference wavelength) and a second wavelength. The illuminating system 14 is an eccentric optical system that is sequentially arranged by the concave reflecting mirror 36, the polarizing filter 38, the imaging lens 37, and the photographic element 39. The concave mirror 36 is the same mirror as the concave mirror 35 of the illumination system 13, and the incident optical axis 〇2 is on the same plane as the normal axis 1A and the optical axis οι of the concave mirror 35, and the incident light is incident. The angle formed by the axis 2 and the normal ia is the same as the angle formed by the exit optical axis 〇1 and the normal 丨A. Therefore, the specular reflected light from the detected wafer 2 (the secondary diffracted light travels along the incident optical axis 02 of the concave mirror 36. The concave mirror 36 reflects the positive reflected light L2 and directs it to the polarizing filter. 38, and cooperate with the imaging lens 37 to form a reflection image of the detected wafer 20 on the photographic surface of the photographic element 39. Here, the orientation of the transmission axis of the polarization filter 38 is set to and illumination 20 200907292 System 1 3 The transmission axis of the polarizing filter 34 is orthogonal (the state of the orthogonal polarization (cr〇ss_nicol)), so that the linearly polarized light L4 passing through the polarizing filter 38 is equivalent to the linearly polarized light in the specular reflected light L2. The polarization component of the polarization azimuth is orthogonal, and the intensity of the linear polarization L4 determines the intensity of the reflection image.
該反射像以攝影元件39拍攝。攝影元件39為例如CCD 攝影το件等，將其反射像光電轉換並產生電氣訊號後，將 其電氣訊號往電路或計算機等構成之控制運算裝置送 出。 如此’受光系統14，發揮檢測形成於被檢測晶圓2〇 之L/S圖案12反射之正反射光（〇次繞射光）之檢測系統 的功能。 控制運算裝置1 5 ’係根據其電氣訊號辨識被檢測晶圓 2〇之反射影像，並根據其反射影像上之各區域的亮度對 各照射區域判斷被檢測晶圓2〇上之圖案的缺陷程度。具 體而s，控制運算裝置15，根據攝影元件39針對第丨波 長（基準波長）所檢測出之正反射光（〇次繞射光）之光強度與 針對第2波長所檢測出之正反射光（〇次繞射光）之光強度 的強度比，發揮作為測定s圖案丨2之間距之測定系統 的功能。 控制運算裝置15設有表’以表示針對第1波長（基準 波長）所檢測出之正反射光（0次繞射光）之光強度與針對各 波長所檢測出之正反射光（0次繞射光）之光強度的強度比、 與L/s圖案之間距的對應關係。控制運算裝置1 5根據該 21 200907292 表，自光強度之強度比與帛 乐，皮長值求出被檢測晶圓20 之L/ S圖案的間距。 控制運算裝置15亦發揮作為 早忭马艮00判定系統之功能，亦 即將以此方式獲得之被檢剛 ^ 日圓之L/ S圖案之間距與 預先设疋於控制運算裝置丨5 之目铽值比較，根據其比較 結果進行被檢測晶圓20為ρ φώ 4良印與否之良品判定。控制運 算虞置1 5之良σο判定，呈贈而t ^ 5，係進行例如所測定之 B巨目標值之差值（差值之、^ ^ ^ ^ 列但預先設定之閾值為 大時’則判斷被檢測晶圓2〇為不良品。 Μ 又’控制運算裝置15，除了 .插、室~丄 以主 陈了此種運异功能，亦具有控 制表面檢查裝置10之各部的控制功能。 其次，參照圖9所示之流程圖， 之矣；认* a+ 況明以第2實施形態 之表面檢查裝置1〇來檢查形 2〇^ 珉有圖案之被檢測晶圓 2〇之表面的方法。首先，切換 L / ς m ^ 2個波長之光並照射於 L/S圖案（照射步驟S201) 0 1體 轉H西 體而吕，例如使轉台12b旋 專精由選擇透過聚光透鏡20朝導光& 尤尤纖33射入之平行 先束所通過之波長選擇過濾器F1，F2，F3，F4 F :?個波長之光並照射。使藉由波長選擇過據器f"”;刀 Μ A F6所選擇波長之光，透過聚光透鏡％朝導光光纖 射入。使自導光光纖33射出之光射人偏振過瀘器Μ。 ::振過滤器34之光轉換為直線偏振。使 =之光在凹面反射鏡35反射並相對於載 = 線傾斜射入，使昭射被檢測曰 居 S20l)。 之大致全面（照射步驟 22 200907292 使在被檢測晶圓20反射之正反射光（〇次繞射光）在凹 面反射鏡36反射並射入偏振過濾器38。使通過偏振過濾 器38之光射入於成像透鏡37。通過成像透鏡37之光，於 攝影凡件39之攝影面上形成被檢測晶圓2〇之反射像。藉 此自被檢測晶圓20之L/ S圖案來之〇次繞射光於攝影 元件3 9被檢測出（檢測步驟S202)。 接著，於檢測步驟S202根據作為第！波長所檢測出 之〇次繞射光之光強度與作為第2波長所檢測出之〇次繞 射光之光強度的強度比，於控制運算裝置15測定被檢測 晶圓20之L/S圖案之間距（測定步驟S2〇3)。於攝影元件 39自反射像光電轉換所產生之電氣訊號，自攝影元件叨 供應至控制運算裝置15。 控制運算裝置15預先設有表，用以表示針對基準波長 即第1波長所檢測出之光強度與針對其他各波長所檢測出 之光強度的強度比、與L/S圖案之間距的對應關係。然 後，根據該表’自強度比與第2波長值求出被檢測晶圓2〇 之L/ S圖案的間距。 其次，將在測定步驟S203所測定之被檢測晶圓2〇之 /圖案之間距與預先設定之目標值比較，根據其結果進 行被檢測晶圓20 $良品與否之良品判定（良品判定步驟 S204)。在良品判定步驟，例如所測定之間距與目標值之差 值（差值之絕對值）比閾值為大時，則判斷被檢測晶圓為 不良品’在閾值以下時’則判斷被檢測晶圓20為良品。 以上，雖已說明本發明之理想實施形態，但本發明並 23 200907292 不限定於此等實施形態。例如，朝L/s圖案之入射光， 亦可不為直線偏振狀態之光。又，所檢測出之〇次繞射光， 亦可不具有與朝L/S圖案之入射光之偏振方向正交之偏 振方向。X，朝L/S圖案之入射光，亦'可不沿著圖 案之間距方向及長邊方向兩者交叉之方向。又，朝L/S 圖案之入射光，亦可不為在L/s圖案之間距方向及長邊 方向兩者交又之方向具有偏振方向的光。 本發明可利用於，能使用較長波長之光來測定L/s 圖案之間距之間距測定裝置及方法。 又，本發明不受實質L/S圖案之粗糙度的影響，可 利用於’能高精度地敎L/s圖案之間距之間距測定裝 置及方法。 【圖式簡單說明】 圖1係概略表示本發明第i實施形態之間距測定裝置 的構成圖。 圖2係概略表示第1實施形態之間距測定裝置之測定 ’象之L/ S圖案的構成圖’⑷表示俯視圖，(b)表示沿(a) 之線A-A方向亦即間距方向的截面圖。 圖3係表示形成於光阻之L/s圖案之起伏（粗縫幻的 示意圖。 圖4係表示於第！數值例，就不同粗糙度振幅之l/s /、針對各波長之光所檢測出之偏振旋轉成分之光強度的 24 200907292 圖5係表示於第2數值例，就不同粗糙度振幅之L/s 圖案針對各波長之光所檢測出之偏振旋轉成分之光強度的 圖。 圖6係用以說明以第1實施形態之間距測定裝置測定 L/ S圖案之間距之方法的流程圖。 圖7係表示具有不同間距之取樣圖案之第2波長與光 強度之強度比之關係的圖表。 圖8係概略表示第2實施形態之表面檢查裝置的全體 構成圖。 圖9係用以說明以第2實施形態之表面檢查裝置判定 被檢查晶圓是否為良品之方法的流程圖。 【主要元件符號說明】 1, la 光源 2 波長選擇過濾器 3 偏振元件 4 檢光元件 5 光檢測器 6 測定系統 10 表面檢查裝置 11 物體 12 L/S圖案 12a 線部 12b 空間部 25 200907292 13 照明系統 14 受光系統 15 控制運算裝置 20 被檢測晶圓 31 光源 33 導光光纖 34, 38 偏振過濾器 35, 36 凹面反射鏡 37 成像透鏡 39 攝影元件 AL 對準系統 FI -F6 波長選擇過濾器 ST 載台 26This reflection image is taken with the photographic element 39. The photographic element 39 is, for example, a CCD image pickup device, and photoelectrically converts the reflected image to generate an electrical signal, and then sends the electrical signal to a control arithmetic device such as a circuit or a computer. The 'light-receiving system 14' functions as a detection system for detecting the specular reflected light (the primary diffracted light) reflected by the L/S pattern 12 of the detected wafer 2A. The control computing device 1 5 ' identifies the reflected image of the detected wafer 2 根据 according to the electrical signal thereof, and determines the degree of defect of the pattern on the detected wafer 2 各 according to the brightness of each region on the reflected image. . Specifically, the control arithmetic unit 15 controls the light intensity of the specular reflected light (the primary diffracted light) detected by the imaging element 39 with respect to the second wavelength (reference wavelength) and the positive reflected light detected for the second wavelength ( The intensity ratio of the light intensity of the sub-circumferential light is used as a function of a measurement system for measuring the distance between the s-patterns 丨2. The control arithmetic unit 15 is provided with a table 'to indicate the light intensity of the specular reflected light (zero-order diffracted light) detected for the first wavelength (reference wavelength) and the specular reflected light detected for each wavelength (zero-order diffracted light) The intensity ratio of the light intensity and the correspondence between the L/s pattern. The control arithmetic unit 15 obtains the pitch of the L/S pattern of the wafer to be inspected 20 from the intensity ratio of the light intensity and the length of the skin according to the 21 200907292 table. The control arithmetic unit 15 also functions as a function of the early 忭 艮 00 determination system, that is, the distance between the L/S patterns of the detected ^ 日 yen obtained in this way and the target value set in advance by the control arithmetic unit 丨 5 For comparison, based on the comparison result, the quality of the detected wafer 20 is ρ φ ώ 4 or not. The control operation device sets a good σο determination, and presents t ^ 5, for example, the difference between the measured B giant target values (the difference, ^ ^ ^ ^ column, but the preset threshold is large) Then, it is judged that the detected wafer 2 is defective. Μ The 'control arithmetic unit 15' has a control function for controlling each part of the surface inspection apparatus 10 in addition to the insertion and the room function. Next, referring to the flowchart shown in FIG. 9, the method of inspecting the surface of the detected wafer 2 to be patterned by the surface inspection apparatus 1A of the second embodiment will be described. First, the light of L / ς m ^ 2 wavelengths is switched and irradiated to the L/S pattern (irradiation step S201). 0 1 body is rotated to the west body, for example, the turntable 12b is rotated by the selective focusing lens 20 The wavelength selection filter F1, F2, F3, F4 F is selected by the wavelength of the parallel light beam that enters the parallel beam of the Eugene fiber 33; and the light is irradiated by the wavelength selection filter f" The light of the wavelength selected by the blade A F6 is incident on the light guiding fiber through the condenser lens %, and the self-guided optical fiber 33 is emitted. The light is polarized through the Μ Μ :: The light of the vibration filter 34 is converted into a linear polarization, and the light of the light is reflected by the concave mirror 35 and obliquely incident with respect to the load = line, so that the illuminating is detected and the S20l is detected. The illumination is substantially uniform (illumination step 22 200907292 causes the specular reflected light (the primary diffracted light) reflected by the detected wafer 20 to be reflected by the concave mirror 36 and incident on the polarizing filter 38. The light passing through the polarizing filter 38 is made The image is incident on the imaging lens 37. The reflected image of the detected wafer 2 is formed on the photographic surface of the photographic element 39 by the light of the imaging lens 37. Thereby, the L/S pattern of the wafer 20 is detected. The sub-diffracted light is detected by the imaging element 39 (detection step S202). Next, in the detecting step S202, the intensity of the light of the diffracted light detected as the first wavelength and the number of times detected as the second wavelength are detected. The intensity ratio of the intensity of the diffracted light is measured by the control computing device 15 to determine the distance between the L/S patterns of the detected wafer 20 (measurement step S2 〇 3). The electrical signal generated by the photoelectric conversion of the photographic element 39 from the reflected image is Self-photographic component 叨 supply to control Device 15. The control computing device 15 is provided with a table for indicating the intensity ratio of the light intensity detected for the first wavelength, that is, the light intensity detected for the other wavelengths, and the distance between the L/S patterns. Then, the pitch of the L/S pattern of the detected wafer 2A is obtained from the self-intensity ratio and the second wavelength value according to the table. Next, the detected wafer 2 measured in the measurement step S203 is 〇 The distance between the patterns/patterns is compared with a predetermined target value, and a good quality determination of the detected wafer 20$ is determined based on the result (good quality determination step S204). In the good product determination step, for example, when the difference between the measured distance and the target value (the absolute value of the difference) is larger than the threshold value, it is determined that the detected wafer is a defective product 'below the threshold value', then the detected wafer is determined. 20 is a good product. Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments. For example, incident light toward the L/s pattern may not be light in a linearly polarized state. Further, the detected diffracted light may not have a polarization direction orthogonal to the polarization direction of the incident light toward the L/S pattern. X, the incident light toward the L/S pattern may also not follow the direction in which the distance between the pattern and the longitudinal direction intersect. Further, the incident light toward the L/S pattern may not be light having a polarization direction in a direction in which both the distance direction and the long side direction between the L/s patterns intersect. The present invention can be utilized in a device and method for measuring the distance between L/s patterns using light of a longer wavelength. Further, the present invention is not affected by the roughness of the substantial L/S pattern, and can be utilized as a measuring device and method for accurately separating the distance between the L/s patterns. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view schematically showing the configuration of a distance measuring device according to an i-th embodiment of the present invention. Fig. 2 is a plan view schematically showing the measurement of the L/S pattern of the image of the first embodiment. (4) is a plan view, and (b) is a cross-sectional view taken along the line A-A direction of (a). Fig. 3 is a schematic view showing the undulation of the L/s pattern formed on the photoresist (a rough phantom diagram. Fig. 4 is a diagram showing the numerical example of the L/s of different roughness amplitudes, and the detection of light for each wavelength. The light intensity of the polarization-rotating component 24 200907292 FIG. 5 is a view showing the light intensity of the polarization-rotation component detected for each wavelength of light in the L/s pattern of different roughness amplitudes in the second numerical example. 6 is a flowchart for explaining a method of measuring the distance between the L/S patterns by the distance measuring device according to the first embodiment. Fig. 7 is a view showing the relationship between the intensity ratio of the second wavelength and the light intensity of the sampling pattern having different pitches. Fig. 8 is a view schematically showing the overall configuration of the surface inspection apparatus according to the second embodiment. Fig. 9 is a flowchart for explaining a method of determining whether or not the wafer to be inspected is good by the surface inspection apparatus according to the second embodiment. Explanation of main component symbols] 1, la light source 2 wavelength selection filter 3 polarization element 4 light detecting element 5 photodetector 6 measurement system 10 surface inspection device 11 object 12 L/S pattern 12a line portion 12b space portion 25 200907292 13 Lighting system 14 Light-receiving system 15 Control computing device 20 Detected wafer 31 Light source 33 Light-guiding fiber 34, 38 Polarization filter 35, 36 Concave mirror 37 Imaging lens 39 Photographic element AL Alignment system FI-F6 Wavelength selection Filter ST stage 26