1345055 九、發明說明： 【發明所屬之技術領域】 本發明一般係關於分析儀器，更明確地說，係關於使用X 射線來進行薄膜分析之儀器與方法。 【先前技術】 X射線反射量測（XRR)係用於測量沈積於基板上之薄膜 層之厚度、密度與表面品質的熟知技術。有多家公司出售 傳統的X射線反射量測儀’其中包括Techn〇s(曰本大阪）、 西門子（德國慕尼黑）與Bede科學儀器（英國德罕）。此類反射 量測儀一般藉由以一掠入射（grazing incidence)將一 X射線 光束照射於一樣品上而操作，即與樣品之表面成非常小的 角度，接近樣品材料的全外反射角。根據角度來測量從樣 品反射的X射線強度可以提供干涉條紋的圖案，分析該圖案 乂决疋負貝產生條紋圖案之薄膜層的性質。通常使用位置 感測摘測器來測量X射線的強度，例如比例計數器或陣列债 測器，一般為光二極體陣列或電荷耦合元件（CCD)〇 例如，在K〇miya等人的美國專利第5,74〇,226號中說明用 於分析X射線資料以決定薄膜厚度的方法，該專利之揭示内 容係以引用的方⑽入本文中。根據角度測量χ射線反射之 後’將-平均反射曲線擬合於條紋光譜。該平均曲線係基 於一表示薄膜之衰減、背景與表面糙度的公式。接著，使 :擬合的平均反射曲線來摘取條紋光譜的振盪成分。將此 成为進行傅立葉變換以求出薄膜厚度。 ⑽的美國專利第5,619,548號說明—基於反射量測測 96959.doc 1345055 量之x射線厚度計，該專利係以引用方式併入本文中。使用 一彎曲的反射式X射線單色器來將x射線聚焦於一樣品之 表面上。一位置感測偵測器，例如光二極體偵測器陣列， 感測從表面反射的X射線’並且根據反射角產生一強度信 號。分析與該角度有關的信號，以決定樣品上一薄膜層之 結構性質，包括厚度、密度與表面糙度。1345055 IX. Description of the Invention: TECHNICAL FIELD OF THE INVENTION The present invention relates generally to analytical instruments and, more particularly, to apparatus and methods for performing thin film analysis using X-rays. [Prior Art] X-ray reflectance measurement (XRR) is a well-known technique for measuring the thickness, density and surface quality of a thin film layer deposited on a substrate. A number of companies sell traditional X-ray reflectometry instruments, including Techn〇s (Sakamoto Osaka), Siemens (Munich, Germany) and Bede Scientific Instruments (Derhan, UK). Such reflectometry is typically operated by irradiating an X-ray beam onto a sample with a grazing incidence, i.e., at a very small angle to the surface of the sample, near the total external reflection angle of the sample material. Measuring the intensity of the X-rays reflected from the sample according to the angle can provide a pattern of interference fringes which are analyzed to determine the properties of the film layer of the stripe pattern. Position sensing tickers are commonly used to measure the intensity of X-rays, such as proportional counters or array detectors, typically photodiode arrays or charge coupled devices (CCD), for example, in U.S. Patent No. K. Miyam et al. A method for analyzing X-ray data to determine film thickness is described in U.S. Patent No. 5,074, the disclosure of which is incorporated herein by reference. The 'average-reflection curve' is fitted to the fringe spectrum after the x-ray reflection is measured from the angle. The average curve is based on a formula representing the attenuation, background and surface roughness of the film. Next, the average reflection curve of the fit is used to extract the oscillating component of the fringe spectrum. This was subjected to Fourier transform to determine the film thickness. U.S. Patent No. 5,619,548, the disclosure of which is incorporated herein by reference. A curved reflective X-ray monochromator is used to focus the x-rays onto the surface of a sample. A position sensing detector, such as an array of photodiode detectors, senses X-rays reflected from the surface and produces an intensity signal based on the angle of reflection. The signal associated with the angle is analyzed to determine the structural properties of a film layer on the sample, including thickness, density, and surface roughness.
Barton等人的美國專利第5,923,72〇號亦說明一基於彎曲 晶體單色器之X射線光譜儀，該專利之揭示内容係以引用的 方式併入本文中。5亥單色器具有一錐形對數螺旋之形狀， 其被說明為可以在樣品表面上達成比先前技術單色器更精 細的焦點。藉由一位置感測續測器接收從樣品表面反射或 繞射的X射線。 ^khin等人的美國專利第6 512 814與6 639,则號說明反 射量測裝置，其包括-輕射源，該輻射源係調適成使用輕 ^在與樣品表面所成的角度範圍内照射樣品；以及一偵測 益組件，其係放置成接收在該角度範圍内從該樣品反射的 輻射’並根據該反射產生一信號。將一擋板可調整地放置 成攔截該輻射，該擋板具有—阻擋位置，其中該擋板阻擋 該角度範圍之較低部分中的韓射，從而使所反射的輻射能 夠到達實質上僅在該範圍之較高部分中的陣列，以及一不An X-ray spectrometer based on a curved crystal monochromator is also described in U.S. Patent No. 5,923,72, the entire disclosure of which is incorporated herein by reference. The 5 liter monochromator has the shape of a conical logarithmic spiral which is illustrated to achieve a finer focus on the sample surface than prior art monochromators. X-rays reflected or diffracted from the surface of the sample are received by a position sensing retort. U.S. Patent Nos. 6,512,814 and 6, 639, the entire disclosure of which is incorporated herein by reference to U.S. Pat. a sample; and a detection component disposed to receive radiation reflected from the sample over the range of angles and generating a signal based on the reflection. A baffle is adjustably placed to intercept the radiation, the baffle having a blocking position, wherein the baffle blocks the Korean shot in the lower portion of the angular range such that the reflected radiation can reach substantially only The array in the upper part of the range, and a no
阻撞位置，其中該Y 把圍之較低部分令的輻射實質上未受阻 擋地到達該陣列。 on等人;^題為「在角分解分散模式中用於掠過X射 線反射$測之新|置」的論文中說明X射線反射量測測量之 96959.doc 1345055 另一常用方法，該論文發表於應用結晶學期刊（Applied Crystallography) 22 (1989)第460頁，並以引用的方式併入 本文。以掠入射將X射線之發散光束引導至樣品表面，並且 在X射線光束源對面的一偵測器收集所反射的X射線。使一 刀口靠近樣品表面，緊貼測量位置上方，以便切斷初級X 射線光束。樣品與偵測器之間（而不是像美國專利第 5,619,548號那樣位於光束源與樣品之間）的一單色器選擇 要到達偵測器的所反射X射線光束之波長。 XRR可原地使用’在一沈積爐内，以在生產中檢查半導 體晶圓上的薄膜層，例如’如Hayashi等人的美國專利申請 公開案第US 2001/0043668 A1號所述，該公開案的揭示内 谷係以引用方式併入本文中。該沈積爐的侧壁上具有X射線 入射與擷取窗口。透過入射窗口照射其上沈積有薄膜的基 板，並透過X射線擷取窗口感測從基板反射的χ射線。 【發明内容】 本發明之具體實施例提供一種用於執行具有加強準確性 之XRR測量的方法與系統。此等方法與系統的優點在於， 分析薄膜層’特別是表現沈積於高密度下部層（例如矽晶圓） 上的低密度材料（例如低k多孔介電質）的特徵。 在本發明的某些具體實施例中，根據下部層的已知反射 性質來校準由薄膜層所產生的XRR條紋圖案之角標度。條 紋圖案的結構取決於薄膜的密度、厚度與其他性質，但該 圖案在來自下部層的全外反射之臨界角處可能還包括一獨 特的肩部’特別係當薄膜層的密度低於下部層的密度時。 96959.doc U45055 此6¾界角進而取決於 取决於下部層的組成物與密度。如果下部層 的參數已知（例如，當下部層係石夕晶圓基板的情況），可根據 肩部的位置精確地校準XRR條紋圖㈣角標度。 在本發明之其他具體實施例令，使用X射線谓測器元件陣 列來測量具有次像素解析度的xrr條紋圖案。基於此目 藉由#聚的X射線光束來照射樣品。該陣列的位置與 方位使4陣列的元件沿一與樣品平面垂直的軸分解從該樣 反射的輻射。然後沿該軸將該陣列平移—小於陣列間距 的杧里並重複測量。較佳地，該增量等於陣列間距的整 數刀數（間距/n ’其中讀、—整數），並且在該陣列沿轴的n 個不同位置處重複測量。通常藉由交錯在不同增量下所作 的測1來組合在不同位置處所作的XRR測量，以便獲得具 有加強解析度之條紋光譜。 儘管本文所述本發明之具體實施例主要關於加強薄膜上 的X射線測量，特別係在半導體晶圓上所形成的薄膜上，但 本發明的原理同樣可用於其他X射線反射量測與散射應 用’以及其他類型的基於輻射的分析。 因此，根據本發明一具體實施例，提供一種用於檢查樣 品的方法，該樣品包括一第一層，其具有一已知的反射性 質；以及一第二層，其形成於該第一層之上，該方法包括： 將輻射引導至該樣品之一表面； 感測從該表面所反射的輻射’以便根據與該表面所成的 仰角產生一反射信號； 在該反射信號中識別由於該輻射從該第一層反射而引起 96959.doc 1345055 的一特徵； 根據該所識別的特徵以及該第-層的已知反射性質來校 準該反射信號；以及 分析所校準的該反射信號以決定該第二層的一特性。 通常，該輻射包括X射線，並且感測該輕射包括在具有一 垂直於該表面的陣列轴之偵測器元件陣列處接收該輻射。 在所揭示的具體實施例中，識別該特徵包括在該反射信 號中找到與來自第—層之全外反射之臨界角對應的一肩部 位置。通常，校準該反射信號包括比較該肩部位置與該臨 界角的-已知值，該值係由該第一層的一已知密度所決 定。校準反射信號通常包括根據該肩部位置與該臨界角的 已知值以在該反射信號的角標度中找到—零角。 在某些具體實施例中，當來自該第一層之全外反射之臨 界角係第-臨界㈣’分析所校準的反射信號包括決定來 自該第二層之全外反射之第二臨界角的校準值。通常，該 等第-與第二層具有各自的第一與第二密纟，並且分㈣ 杈準的反射信號包括根據第二臨界角的 二密度…該第二密度可能實質上小於該第一== 一具體實施例中，該第—層包括石夕，而該第二層包括 孔介電材料。 因此，根據本發明一具體實施例，還提供一種用於檢查 性：的裝置，該樣品包括一第一層，其具有—已知的反射 質，以及一第二層，其形成於該第一層之上，該裝置勺 括： 96959.doc 1345055 一輻射源，其係調適成將X射線引導至該樣品的一表面； 一偵測器組件，其係配置成感測從該表面所反射的輻 射’以便根據與該表面所成的仰角產生一反射信號；以及 一信號處理器，其係耦合以接收該反射信號，並藉由在 該反射信號中識別由於該輻射從該第一層的反射而引起的 一特徵並且根據該所識別的特徵以及該第一層之已知反射 性質而校準該反射信號來處理該反射信號，以及分析所校 準的該反射信號以決定該第二層的一特性。 根據本發明一具體實施例，另外提供一種用於檢查樣品 的裝置，其包括： 一輕射源’其係調適成將X射線引導至該樣品的一表面； 一偵測器組件，其包括： 一偵測器元件陣列，該等偵測器元件係沿一實質上垂 直於該表面的一陣列軸配置，相互分開一預定間距，並 且係操作以接收從該表面反射的X射線，以及回應於所接 收的輻射而產生信號；以及 一移動元件，其係耦合以沿一平行於該陣列轴的方向 在至少第一與第二位置之間偏移該偵測器元件陣列，該 等位置係相互分開一增量’該增量非為該間距的整數 倍；以及 一 i號處理器’其係搞合以組合藉由該该測器組件在至 少該等第一與第二位置所產生的信號，以便根據與該表面 所成的仰角來決定該表面的X射線反射。 一般而言’該信號處理器係調適成交錯藉由該偵測器組 96959.doc •10· 1345055 以便決定該 件在至少料第一與第二位置所產生的信號 表面的X射線反射。 在所揭示的具體實施例中 一半。 該增量小於或等於該間距的 -般而言，該陣列包括一線性陣列，並且該偵測器元件 具有-橫向尺寸’垂直於該陣列軸，其係實質上大於該陣 列的一間距。或者，該陣列包括該等偵測器元件之一二維 矩陣，並且該偵測器組件係調適成沿一垂直於陣列軸的方 向將摘測器元件裝配於陣列之個別列中。 根據本發明一具體實施例，進一步提供一種用於檢查樣 品的方法，其包括： 將X射線引導至該樣品之一表面； 配置一偵測器元件陣列，該等元件係相互分開一預定間 距，用以接收從該表面反射的X射線，同時分解沿一實質上 垂直於該表面的陣列軸所接收的輻射； 沿一平行於該陣列轴的方向在至少第一與第二位置之間 偏移該偵測器元件陣列，該等位置係相互分開一增量，該 增量非為該間距的整數倍； 接收至少第一與第二信號，該等信號係由該偵測器元件 分別回應於在至少該等第一與第二位置所接收的X射線而 產生；以及 組合至少該等第一與第二信號，以便根據與該表面所成 的仰角來決定該表面的一 X射線反射。 根據本發明一具體實施例，進一步提供一種用於生產微 96959.doc 電子元件的群集工具，其包括： 一沈積台，其係調適成將一笼 乂將溥臈層沈積於一半導體晶圓 表面上的一下部層之上，該下邮思目士 发卜。P層具有一已知的反射性 質；以及 一檢查台，其包括： 一輻射源，其係調適成將乂射線引導至該晶圓的表面； 债測器組件’其係配置成感測從該表面所反射的輻 射，以便根據與該表面所成的仰角產生一反射信號；以及 —信號處理器，其係耦合以接收該反射信號，並藉由 在該反射t號中識別由於該輻射從該下部層的反射而引 起的一特徵並且根據該所識別的特徵以及該下部層之已 知反射性質而校準該反射信號來處理該反射信號，以及 分析所校準的該反射信號以決定該沈積台所沈積之薄膜 層之特性。 根據本發明一具體實施例，進一步提供一種用於生產微 電子元件的裝置，其包括： 一生產室’其係調適成接收一半導體晶圓； 一沈積元件，其係調適成將一薄膜層沈積於該室内該半 導體晶圓表面上的一下部層之上，該下部層具有一已知的 反射性質； 一輕射源’其係調適成將X射線引導至該室内該半導體晶 圓的表面； 一偵測器組件，其係配置成感測從該表面所反射的輻 射’以便根據與該表面所成的仰角產生一反射信號；以及 一 h號處理器，其係搞合以接收該反射信號’並藉由在 96959.doc -12- 1345055 該反射信號中識別由於該輕射從該下部層的反射而引起的 -特徵束且根據該所識別的特徵以及該下部層之已知反射 性質而校準該反射信號來處理該反射信號，以及分析所校 準的該反射信號以決定該汰接士 ^ 疋成/尤積兀件所沈積之薄膜層之特 性。 根據本發明-具體實施例，還提供—種詩生產微電子 元件的群集工具，其包括： 沈積台，其係調適成將一薄膜層沈積於一半導體晶圓 的表面上；以及 一檢查台，其包括： 一輻射源，其係調適成將X射線引導至該晶圓的表面； 一偵測器組件，其包括： 一偵測器元件陣列，該等偵測器元件係沿一實質上 垂直於該表面的一陣列軸配置，相互分開一預定間 距，並且係操作以接收從該表面反射的χ射線，以及回 應於所接收的轄射而產生信號；以及 一移動元件，其係耦合以沿一平行於該陣列轴的方 向在至少第一與第二位置之間偏移該偵測器元件陣 列’該等位置係相互分開一增量，該增量非為該間距 的整數倍；以及 一信號處理器，其係耦合以組合藉由該偵測器組件在至 少該等第一與第二位置所產生的信號，以便根據與該表面 所成的仰角來決定該薄膜層的X射線反射。 根據本發明一具體實施例，另外提供一種用於生產微電 96959.doc •13- 1345055 子元件的裝置，其包括： 一生產室，其係調適成接收一半導體晶圓； 一沈積元件，其係調適成將一薄膜層沈積於該室内該半 導體晶圓的表面上； 一輻射源’其係調適成將X射線引導至該室内該半導體晶 圓的表面； 一偵測器組件，其包括： 一偵測器元件陣列，該等偵測器元件係沿一實質上垂 直於該表面的一陣列軸配置，相互分開一預定間距，並 且係操作以接收從該表面反射的X射線，以及回應於所接 枚的輻射而產生信號；以及 一移動元件’其係耦合以沿一平行於該陣列軸的方向 在至少第一與第二位置之間偏移該偵測器元件陣列，該 荨位置係相互分開一增量，該增量非為該間距的整數 倍，以及 k號處理器’其係搞合以組合藉由該债測器組件在至 少該等第一與第二位置所產生的信號，以便根據與該表面 所成的仰角來決定該薄膜層的X射線反射。 根據本發明一具體實施例，進一步提供一種用於檢查樣 品的方法，其包括： 將來自第一預定位置中之輻射源的輻射引導至第二預定 位置中的輻射感測器； 感測來自該輻射源、直接入射於該輻射感測器上的輻 射’以根據仰角產生第一直接信號，同時將一擋板放置成 96959.doc 14 1345055 以預定的切斷角度切斷該輻射； 感測來自該輻射源、直接入射於該輻射感測器上的輻 射’以根據仰角產生第二直接信冑，同時將一擔板放置成 不以該預定的切斷角度切斷該輻射； 將-樣品引人第-預定位置中之輻射源與該第二預定位 置中之輻射感測器之間，以使該輕射可入射於該樣品的— 表面上； 感測從該樣品之表面反射到該輻射感测器上的賴射，以 根據仰角產生第一反射信號’同時將一擋板放置成以該預 定的切斷角度切斷該輻射； 感測從該樣品之表面反射到該輕射感測器上的輕射，以 根據仰角產生第二反射信號，同時將—擋板放置成不以該 預定的切斷角度切斷該輻射；以及 將第一直接信號與第二直接信號之間的第一比率與第一 反射信號與第二反射信號之間的第二比率進行比較/，以便 求出切線與表面所成的仰角。 一般而言，該方法包括分析該等第—與第二反射信號， 以便決定薄膜層在該樣品表面的性質。 在所揭示的具體實施例中，將第—比率與第二比率進行 比較包括求出第一仰角，在該仰角下第一比率具有一給定 值；以及第二仰角，在該仰角下第二比率具有該給定^ 以及將切線與表面所成之仰角決定為第—與第二仰角的平 均值。在補充或替代方案中’該方法包括在該等第—與第 二仰角之間作差，以便決定-最小仰角，低於該最小仰角 96959.doc 15 1345055 時，該擋板切斷該輻射。 根據本發明一具體實施例，另外提供一種用於檢查樣品 的裝置，其包括： 第一預定位置的輻射源，其係調適成產生輻射； 一撐板’其係可放置成以預定的切斷角度切斷輻射； 一移動級，其係配置成放置一樣品，使輻射源所產生的 輻射能夠入射於該樣品的一表面上； 第二預定位置的輻射感測器，其係調適成感測該輻射， 以便回應於入射於該輻射感測器上的輻射而根據仰角產生 信號’該等信號包括： 一第一直接信號，其係回應於當將擋板放置成以預定 的切斷角度切斷韓射時，來自輕射源、直接入射於該輕 射感測上的轄射； 第一直接信號，其係回應於當將擋板放置成不以預 疋的切斷角度切斷輻射時，來自輕射源、直接入射於該 輻射感測器上的輻射； 第反射信號’其係回應於當將擂板放置成以預定 的切斷角度切斷輻射時，從樣品表面反射到該輻射感測 器上的輪射；以及 乐一反射信號，其係回應 /、丨尔四應於荀册痛极風置成不以The blocking position, wherein the lower portion of the Y causes the radiation to reach the array substantially unblocked. On et al.; in the paper entitled "Using X-ray Reflection in the Angle Decomposition Dispersion Mode", the paper describes the X-ray reflectometry measurement 96959.doc 1345055 Another common method, the paper Published on page 460 of Applied Crystallography 22 (1989), and incorporated herein by reference. The diverging beam of X-rays is directed to the surface of the sample at grazing incidence, and the reflected X-rays are collected by a detector opposite the source of the X-ray beam. Place a knife edge close to the surface of the sample and close to the measurement position to cut off the primary X-ray beam. A monochromator between the sample and the detector (rather than between the beam source and the sample as in U.S. Patent No. 5,619,548) selects the wavelength of the reflected X-ray beam that reaches the detector. The XRR can be used in situ in a deposition furnace to inspect a thin film layer on a semiconductor wafer during production, for example, as described in US Patent Application Publication No. US 2001/0043668 A1 to Hayashi et al. The disclosure of the inner valley is incorporated herein by reference. The sidewall of the deposition furnace has an X-ray incident and extraction window. The substrate on which the thin film is deposited is irradiated through the incident window, and the x-rays reflected from the substrate are sensed through the X-ray extraction window. SUMMARY OF THE INVENTION A particular embodiment of the present invention provides a method and system for performing XRR measurements with enhanced accuracy. An advantage of such methods and systems is that the analysis of the film layer', in particular, features of a low density material (e.g., a low-k porous dielectric) deposited on a high density lower layer (e.g., a germanium wafer). In some embodiments of the invention, the angular scale of the XRR fringe pattern produced by the film layer is calibrated based on the known reflective properties of the underlying layer. The structure of the stripe pattern depends on the density, thickness and other properties of the film, but the pattern may also include a unique shoulder at the critical angle of total external reflection from the lower layer, especially when the density of the film layer is lower than the lower layer. When the density. 96959.doc U45055 This 63⁄4 boundary is in turn dependent on the composition and density of the lower layer. If the parameters of the lower layer are known (for example, when the lower layer is the case of the wafer substrate), the XRR fringe pattern (4) angular scale can be accurately calibrated according to the position of the shoulder. In other embodiments of the invention, an xrr fringe element array is used to measure the xrr fringe pattern with sub-pixel resolution. Based on this purpose, the sample was irradiated by a poly-X-ray beam. The position and orientation of the array causes the elements of the 4 array to decompose the radiation reflected from the sample along an axis perpendicular to the plane of the sample. The array is then translated along the axis - less than the array spacing and repeated measurements. Preferably, the increment is equal to the number of integers of the array spacing (pitch / n ' where read, - integer) and the measurements are repeated at n different locations along the axis of the array. The XRR measurements made at different locations are typically combined by interleaving the measurements made in different increments to obtain a fringe spectrum with enhanced resolution. Although the specific embodiments of the invention described herein are primarily directed to X-ray measurements on reinforced films, particularly on thin films formed on semiconductor wafers, the principles of the present invention are equally applicable to other X-ray reflectance measurement and scattering applications. 'And other types of radiation-based analysis. Thus, in accordance with an embodiment of the present invention, a method for inspecting a sample is provided, the sample comprising a first layer having a known reflective property; and a second layer formed on the first layer The method includes: directing radiation to a surface of the sample; sensing radiation reflected from the surface 'to generate a reflected signal according to an elevation angle formed with the surface; identifying in the reflected signal due to the radiation The first layer reflects a feature of 96759.doc 1345055; calibrates the reflected signal based on the identified feature and the known reflective properties of the first layer; and analyzes the calibrated reflected signal to determine the second A characteristic of a layer. Typically, the radiation comprises X-rays and sensing the light comprises receiving the radiation at an array of detector elements having an array axis perpendicular to the surface. In the disclosed embodiment, identifying the feature includes finding a shoulder location in the reflected signal that corresponds to a critical angle of total external reflection from the first layer. Typically, calibrating the reflected signal includes comparing the shoulder position to a known value of the critical angle determined by a known density of the first layer. Calibrating the reflected signal typically includes finding a - zero angle in the angular scale of the reflected signal based on the shoulder position and a known value of the critical angle. In some embodiments, the critical angle of the total external reflection from the first layer is a first critical angle determined by the first critical (four)' analysis of the reflected signal comprising a second critical angle from the total external reflection of the second layer. Calibration value. Typically, the first and second layers have respective first and second keys, and the reflected signals of the (four) level include two densities according to a second critical angle... the second density may be substantially smaller than the first == In a specific embodiment, the first layer comprises a stone eve and the second layer comprises a porous dielectric material. Thus, in accordance with an embodiment of the present invention, there is also provided an apparatus for inspecting: the sample comprising a first layer having a known reflective mass and a second layer formed on the first Above the layer, the device includes: 96959.doc 1345055 A radiation source adapted to direct X-rays to a surface of the sample; a detector assembly configured to sense reflections from the surface Radiating 'to generate a reflected signal based on an elevation angle with the surface; and a signal processor coupled to receive the reflected signal and identifying in the reflected signal a reflection from the first layer due to the radiation And causing a feature and calibrating the reflected signal to process the reflected signal based on the identified characteristic and the known reflective properties of the first layer, and analyzing the calibrated reflected signal to determine a characteristic of the second layer . In accordance with an embodiment of the present invention, there is additionally provided an apparatus for inspecting a sample, comprising: a light source source adapted to direct X-rays to a surface of the sample; a detector assembly comprising: An array of detector elements disposed along an array of axes substantially perpendicular to the surface, separated from each other by a predetermined spacing, and operative to receive X-rays reflected from the surface, and in response to Generating a signal to generate radiation; and a moving element coupled to shift the array of detector elements between at least first and second positions in a direction parallel to the axis of the array, the locations being mutually Separating an increment 'the increment is not an integer multiple of the pitch; and an i-processor' is operative to combine the signals generated by the detector assembly in at least the first and second positions In order to determine the X-ray reflection of the surface based on the elevation angle with the surface. In general, the signal processor is adapted to be interleaved by the detector set 96959.doc • 10· 1345055 to determine the X-ray reflection of the surface of the signal produced by the element at least at the first and second locations. Half of the disclosed embodiments. In general, the increment is less than or equal to the pitch, the array includes a linear array, and the detector element has a - lateral dimension ' perpendicular to the array axis, which is substantially greater than a pitch of the array. Alternatively, the array includes a two-dimensional matrix of one of the detector elements, and the detector assembly is adapted to mount the finder elements in individual columns of the array along a direction perpendicular to the axis of the array. According to an embodiment of the present invention, there is further provided a method for inspecting a sample, comprising: directing X-rays to a surface of the sample; and configuring an array of detector elements, the elements being separated from each other by a predetermined distance, Receiving X-rays reflected from the surface while decomposing radiation received along an array axis substantially perpendicular to the surface; offsetting at least between the first and second positions along a direction parallel to the array axis Array of detector elements, the positions are separated from each other by an increment, the increment is not an integer multiple of the pitch; receiving at least first and second signals, the signals are respectively responded by the detector elements Generating at least the first and second positions of the received X-rays; and combining at least the first and second signals to determine an X-ray reflection of the surface based on an elevation angle with the surface. According to an embodiment of the present invention, there is further provided a cluster tool for producing micro 96159.doc electronic components, comprising: a deposition station adapted to deposit a layer of germanium on a surface of a semiconductor wafer On the lower part of the upper layer, the post will be sent to the mind. The P layer has a known reflective property; and an inspection station comprising: a radiation source adapted to direct the x-ray to the surface of the wafer; the debt detector component is configured to sense from Radiation reflected by the surface to produce a reflected signal based on an elevation angle with the surface; and - a signal processor coupled to receive the reflected signal and identifying from the reflected t number due to the radiation a feature caused by reflection of the lower layer and calibrating the reflected signal to process the reflected signal based on the identified characteristic and the known reflective properties of the lower layer, and analyzing the calibrated reflected signal to determine deposition of the deposition station The characteristics of the film layer. According to an embodiment of the present invention, there is further provided an apparatus for producing a microelectronic component, comprising: a production chamber adapted to receive a semiconductor wafer; and a deposition component adapted to deposit a thin film layer Above the lower layer on the surface of the semiconductor wafer in the chamber, the lower layer has a known reflective property; a light source 'adapted to direct X-rays to the surface of the semiconductor wafer in the chamber; a detector assembly configured to sense radiation reflected from the surface to generate a reflected signal based on an elevation angle formed with the surface; and an h processor configured to receive the reflected signal And identifying the characteristic beam due to the reflection of the light beam from the lower layer in the reflected signal at 96599.doc -12-1345055 and according to the identified characteristic and the known reflective properties of the lower layer The reflected signal is calibrated to process the reflected signal, and the calibrated reflected signal is analyzed to determine characteristics of the thin film layer deposited by the splicer/semiconductor. In accordance with the present invention - a cluster tool for producing microelectronic components is also provided, comprising: a deposition station adapted to deposit a thin film layer on a surface of a semiconductor wafer; and an inspection station, The method includes: a radiation source adapted to direct X-rays to a surface of the wafer; a detector assembly comprising: an array of detector elements, the detector elements being substantially vertical An array of axis configurations on the surface, spaced apart from each other by a predetermined spacing, and operative to receive xenon rays reflected from the surface and to generate signals in response to the received apposition; and a moving element coupled to a direction parallel to the array axis offset between at least the first and second positions of the detector element array 'the positions are separated from each other by an increment, the increment being not an integer multiple of the pitch; and a signal processor coupled to combine signals generated by the detector assembly in at least the first and second positions to determine an X of the film layer based on an elevation angle with the surface Ray reflection. In accordance with an embodiment of the present invention, there is additionally provided an apparatus for producing a micro-electric 96969.doc • 13-13450 55 sub-element, comprising: a production chamber adapted to receive a semiconductor wafer; a deposition element Adapting to deposit a thin film layer on the surface of the semiconductor wafer in the chamber; a radiation source 'adapted to direct X-rays to the surface of the semiconductor wafer in the chamber; a detector assembly comprising: An array of detector elements disposed along an array of axes substantially perpendicular to the surface, separated from each other by a predetermined spacing, and operative to receive X-rays reflected from the surface, and in response to The received radiation generates a signal; and a moving element is coupled to offset the array of detector elements between at least the first and second positions along a direction parallel to the array axis, the position of the element Separating from each other by an increment, the increment is not an integer multiple of the spacing, and the k processor is operatively combined to produce the at least the first and second positions by the debt detector assembly Signal, so as to determine the X-ray reflectivity of the film layer according to the surface elevation. According to an embodiment of the present invention, there is further provided a method for inspecting a sample, comprising: directing radiation from a radiation source in a first predetermined location to a radiation sensor in a second predetermined location; sensing from the a radiation source, radiation directly incident on the radiation sensor to generate a first direct signal according to an elevation angle, while placing a baffle at 96959.doc 14 1345055 to cut the radiation at a predetermined cut-off angle; sensing from The radiation source, the radiation directly incident on the radiation sensor to generate a second direct signal according to the elevation angle, while placing a plate to not cut the radiation at the predetermined cutting angle; Between the radiation source in the first-predetermined position of the person and the radiation sensor in the second predetermined position such that the light shot can be incident on the surface of the sample; sensing the reflection from the surface of the sample to the radiation a radiation on the sensor to generate a first reflected signal according to an elevation angle while placing a baffle to cut the radiation at the predetermined cut angle; sensing reflection from the surface of the sample to the light shot a light shot on the detector to generate a second reflected signal according to the elevation angle while placing the baffle so as not to cut the radiation at the predetermined cut angle; and between the first direct signal and the second direct signal The first ratio is compared to a second ratio between the first reflected signal and the second reflected signal to determine an elevation angle formed by the tangent to the surface. In general, the method includes analyzing the first and second reflected signals to determine the properties of the film layer on the surface of the sample. In a disclosed embodiment, comparing the first ratio to the second ratio includes determining a first elevation angle at which the first ratio has a given value; and a second elevation angle at which the second angle The ratio has the given ^ and the elevation angle formed by the tangent to the surface is determined as the average of the first and second elevation angles. In addition or in the alternative, the method includes making a difference between the first and second elevation angles to determine a minimum elevation angle below which the baffle cuts the radiation when the minimum elevation angle is 96959.doc 15 1345055. In accordance with an embodiment of the present invention, there is additionally provided an apparatus for inspecting a sample, comprising: a first predetermined location of radiation source adapted to generate radiation; a riser 'which can be placed to be cut at a predetermined An angle-cutting radiation; a moving stage configured to place a sample such that radiation generated by the radiation source can be incident on a surface of the sample; and a second predetermined position of the radiation sensor adapted to sense The radiation is responsive to the radiation incident on the radiation sensor to generate a signal based on the elevation angle. The signals include: a first direct signal responsive to when the baffle is placed to be cut at a predetermined cut angle When the Han shot is broken, the light source is directly incident on the light-sensing sensation; the first direct signal is in response to when the baffle is placed so as not to cut the radiation at a pre-cut angle a radiation from a light source directly incident on the radiation sensor; the first reflected signal is responsive to reflection from the surface of the sample to the surface when the jaw is placed to cut the radiation at a predetermined cut angle Shooting on the sensor; and Le-reflecting signal, which responds to /, and Muir should be placed in the slogan
定的切斷角/S： +77 I A 從切斷輪射時，從樣品表面反射到該輻射 測器上的輻射；以及 一信號處理器，甘乂么士 八係輕合以將第一直接信號與第二直 信號之間的第—比 1 手興第一反射信號與第二反射信號之 96959.doc -16 - 1345055 的第二比率進行比較’以便求出切線與表面所成的仰角。 應瞭解，上文與申請專利範圍中的「第一」與「第二」 係任意使用的。因此，例如，此等術語不一定反映出接收 上述信號的實際順序。 根據下文結合附圖對本發明具體實施例所作的詳細說 明，可更充分地瞭解本發明。 - 【實施方式】 現在參考圖1 ’其係根據本發明一具體實施例用於χ射線 反射量測（XRR)之系統2〇的示意侧視圖。系統2〇類似於上述 美國專利第6,512,814號中所說明的又1111系統，不過新增了 本文所述的特徵與能力。 將欲藉由系統20評估的的樣品22，例如一半導體晶圓， 安裝於一移動級24上，以便能夠準確地調整樣品22的位置 與方位。一 X射線源26，通常係一具有適當單色化光學元件 (未顯示）的X射線管，照射樣品22上的小區域28。例如，由 牛津儀器公司（位於加利福尼亞Sc〇tts Valley)生產的 XTF5011 X射線管可用於此目的。光學元件在一會聚光束 27中將來自X射線管的輻射聚焦於區域28上。美國專利第 6,381，303號說明可用於又射線源26的若干不同的光學組 態，該專利的揭示内容係以引用方式併入本文中。例如， 光學元件可包含一彎晶單色器，例如由紐約阿爾巴尼市的 XOS公司所生產的聚焦雙彎晶光學元件。上述美國專利 5,619,548與5,923’720中說明其他適當的光學元件。熟習此 項技術者將明白其他可能的光學組態。系統2〇中之反射量 96959.doc 17 1345055 測與散射測量之典型的X射線能量係大約8.05 keV (CuKal)。或者，可使用其他能量，例如5.4 keV(CrKal)。 使用一動態的刀口 36與擋板38在垂直方向（即垂直於樣 品22的平面）上限制X射線之入射光束27的角範圍，而一狹 缝3 9則可用來在水平方向限制光束。刀口、擋板與狹縫一 起用作一擋板組件，用以調整光束27的橫向尺寸。圖1係舉 例說明擋板組件之組態’用於以下述方式控制光束27之橫 向尺寸的X射線光學元件之替代性配置對於熟習此項技術 者而言係顯然的，並且視為屬於本發明之範疇内。 上述美國專利第6,512,814號詳細說明乂1111測量中刀口36 與擋板38的使用。簡而言之，為最佳地偵測接近0。之低角 度反射’將擋板38撤出入射光束27的範圍之外，而將刀口 36放置於區域28之上’並將其降低以縮小光束的有效垂直 斷面。結果’可減小入射於區域28上的X射線光斑的橫向尺 寸°另一方面’為有效地偵測較弱的、高角度的反射，將 刀口 36從光束27撤出，而將擋板38放置成切斷光束的低角 度部分。（或者’將擋板放置成切斷反射光束29的低角度部 y刀。）以此方式’僅來自樣品22的高角度反射（而非較強的低 角度反射）才能到達偵測器陣列，因而加強高角度測量的信 號/背景比。在xRR測量中，狹縫39通常係敞開的，以便接 納會聚射線的實心錐形，因而增加反射率測量的信號/雜訊 比。 藉由彳貞'則器組件30收集從樣品22反射的X射線反射光束 29 般而言’對於XRR，組件30收集在垂直（仰角-Φ)方向 96959.doc -18- 1345055 上反射角範圍介於大約〇。與3。之間之反射χ射線，此等角度 兼在樣品之全外反射之臨界角以上與以下。(為說明清楚起 見圖中所不的角度有所誇大，例如χ射線源26與伯測器組 件30在圖1中樣品22之平面上的仰角。） 組件30包含一偵測器陣列32，例如ccd陣列，如下所述。 儘官為說明簡潔起見，®中僅顯示單列偵測器元件，其中 有數目相對較少的_器元件，㈣列32-般包括更大數 目的元件配置為一線性陣列或一矩陣（二維）陣列。組件 可此包含一平移元件33，其屬於此項技術中熟知的任何適 當類型，用於相對於樣品22偏移並對準陣列32。組件3〇進 步包含由適當的X射線透明材料（例如皱）所製成的窗口 34 ’距該偵測器陣列前面一間隔，且位於該陣列與該樣品 之間。以下參考圖2說明陣列32之操作之其他細節。 k號處理器40分析組件30的輸出，以便在給定能量或在 一能量範圍内根據角度決定從樣品22反射的X射線光子的 通量分佈42。一般而言，樣品22具有在區域28的一或多個 薄表面層’例如薄膜，以使與仰角成函數關係的分佈42展 示一振盪結構’其係起因於從層之間的介面所反射的X射線 波之間的干擾效應。處理器40使用下述分析方法分析角分 佈的特性，以決定樣品之一或多個表面層之特性，例如層 的厚度、密度與表面品質。 圖2係根據本發明一具體實施例之陣列32的示意正視 圖。此圖中所示陣列32包含單列偵測器元件46，有一陣列 軸沿一與樣品22之平面垂直的軸對準。元件46具有高縱橫 96959.doc •19- 1345055 比，即其在橫穿陣列軸之方向上的寬度實質上大於其沿軸 之間距。高縱橫比有助於加強系統2〇的信號/雜訊比，因為 對於沿陣列轴之每一角增量，陣列32能夠藉此在相對較寬 的區域内收集X射線光子。然而，圖中僅係舉例說明元件46 的尺寸，並且可使用更小或更大縱橫比之元件來應用本發 明之原理，視應用需要與適當偵測器元件之可用性而定。 如上所述，陣列32可包含一線性CCD陣列或一矩陣陣 列，例如日本濱松市之Hamamatsu公司所生產的s7〇32 i〇〇8 型陣列。此後者的陣列包含1044x256個像素，並且總體尺 寸為25_4x6 mm。其能夠以線型裝箱（line_binning)模式操 作，其中使用由H_matsu/Av司為此目的而提供的特殊硬 體，故陣列之每-列中的多個偵測器元件有效地用作具有 高縱橫比的單一元件。在此情形下，儘管陣列32實體上包 含偵測器元件之一二維矩陣，但在功能上，該陣列採取單 列偵測器元件之形式，如圖2所示。 或者’陣列32可&含一具有適當讀出電路之piN二極體陣 列，可能包括整合式處理電子元件，如美國專利第6,389，1们 號所述，該專利的揭示内容係以引用的方式併入本文。此 專利還說明陣列的替代特徵’包括陣列的各種幾何組態卜 維與二維）以及可用於加強陣列之偵測性質的遮罩。此等特 徵亦適用於本專利申請案之組件3〇。在任何情況下，應瞭 解，此處僅係對此等偵測器類型舉例說明而已，可使用任 何適當類型、尺寸與數目的偵測器。 在本發明之-方面，如圖2所述，例如使用平移元件Μ(圖 96959.doc •20· 1345055 1)〜Z方向將陣列32偏移小的增量。圖中顯示陣列32的兩 個垂直位置45與47，其沿Z方向分隔一增量，即陣列間距的 一半，亦即偵測器元件46之中心對中心分離的一半。（儘管 圖2所示位置45與47係水平偏移，但水平偏移在此圖中僅用 於清晰說明之目的，並非XRR測量中必要或所需的）。在每 個位置45與47中驅動X射線源26,組件30捕獲從樣品22反射 的X射線其與仰角成函數關係。組件3 〇可以此方式運作， 以在兩個以上的不同垂直位置捕獲χ射線，通常在該等位置 之間的ζ方向增量較小。例如，可使用分隔陣列間距的 三個不同位置。 ， 將組件30在每個不同垂直位置所產生的信號輸入至處理 器40，其將在不同位置所得到的讀數組合成單一的光譜。 本質上，處理器產生一「虛擬陣列」，其解析度小於實際的 實體陣列32。可導出虛擬陣列中的信㉟，例如只需藉由交 錯在不同陣列位置所得到的讀數。因❿，對於虛擬陣列中 的每個「虛擬像素」，處理器4〇選擇其中一次實際測量中對 應位置之真實像素的測量值，使在不同測量位置所得到的 讀數中從一虛擬像素至下一虛擬像素交替。換言之，假定 以下的讀取像素讀數係在陣列的三個連續位置得到： 位置 1 : Rll、R21、R31、R41、… 位置2 : R12、R22、R32、R42、… 位置 3 : R13、R23、R33、R43、 所得到的虛擬陣列則將在分隔1/3實際陣列間距的虛擬 素處包含下列值： 96959.doc -21 - 1345055 R11、R12、R13、R21、R22、R23、RM、R32、R33、R41、… 或者，可使用其他方法’例如不同陣列位置之讀數的求差 或Ή以在組合讀數之前從個別的實際測量擁取X狀資 訊’或藉以選擇要用於虛擬陣列之每個像素的實際測量結 果。 ‘XRR光譜具有高空間頻率之精細結構時，上文所述的 解析度加強技術特別有用’故條紋分離相當於或小於陣列 間距。或者’當XRR光譜係足夠強，並且條紋係清楚分隔 時，便足以測量單一盡：吉# $ , 早埜直位置（例如位置45)的XRR信號，以 便擷取可接受的光譜。 圖3與4係根據本發明—具體實施例，使用系統2〇所作 XRR測里的不意曲線圖。此種曲線圖可使用陣列Μ之單一 垂直位置所接收的信號，或藉由如上所述組合兩個或兩個 以上不同垂直位置的信號而產生。圖3之曲線圖顯示陣列32 在單一垂直位置所接收的反射χ射線之強度，其與仰角小成 函數關係，其中使用來自乂射線源26的以Κα(8.〇5 “^輻 射。下述圖4顯示將在陣列32之多個不同垂直位置所捕獲的 信號予以組合的結果。 上面的曲線50顯示從裸矽晶圓所測量的反射，而下面的 曲線52顯示來自其上已形成低k多孔介電膜之晶圓的反 射。兩條曲線皆具有一肩部，位於在圖中標記為^的角度， 略大於0.2。。此角度對應於來自矽之全外反射的臨界角。更 精確έ之，對於密度為2.33 g/cm3的標準矽晶圓，8.〇5 keV 的臨界角度為0.227。。因此，一旦找到φ2處肩部的位置，只 96959.doc •22- 1345055 需向Φ2的左邊倒退0.227。，便可精確地決定圖3之光譜申角 (水平）私度的零點。每個偵測器元件46的角標度（以度數計） 的比例因數係由 71 Vfocal dist J π U〇cal dist 中焦距係從聚焦區域28至陣列32的距離。在替代或補充方 案中，使用上述美國專利申請案第1〇/313,28〇號中所述的方 法，根據<h處的肩部，但無需參考陣列間距與焦距，可完 全校準角標度。 在臨界角以上，曲線52顯示一振盪結構，主要係由於來 自低k膜之上部與下部表面的反射所致。可分析此振盪的週 期與振幅，以決定晶圓上之低5^膜（以及可能其他薄膜層）之 厚度與表面品質。例如，可使用快速傅立葉變換來擷 取振盪的相關特性。或者，可使用參數曲線擬合方法來更 準確地決定薄膜參數。在上述美國專利第6,512,814號中更 詳細地說明用於分析XRR信號的方法，例如曲線52。 因此臨界角及反射曲線中的肩部位置，主要係由反射X 射線之材料的密度決定。因為沈積於晶圓上的多孔、低k 介電層具有實質上低於矽基板的密度，故多孔層的臨界角 貫質上小於下方矽的臨界角。因此，曲線52中看到另一肩 部，位於在圖中標記為φι的較小角度，對應於多孔層的臨 界角。可使用Φ2的已知值，根據上述角標度的校準來決定扒 的實際值。於是，處理器4〇能夠根據杌的校準值以高精確 度決定多孔材料的總體密度。因為介電材料（在無孔的情況 下）的本征密度通常係已知的，故可根據佝的測量值，按照 介電材料之已知本征密度與多孔層所估計的總體密度之間 96959.doc •23· 1345055 的差’推出孔的總體積、多孔層的每單位體積。 圖”肩不由陣列32所接收與仰角Φ成函數關係的反射X射 =強度’說明將在陣列不同垂直位置所作多個測量予以組 口的果此圖中的角標度相對於圖3中的角標度有所擴 ^原始曲線54顯示陣列32之單—垂直位置所作的典型測 置。組合曲線56顯示藉由組合在陣列不同垂直位置所作的 五次測量而獲得的結果，該等位置在2方向上相互偏移ι/5 陣歹J間距之增里。陣列的間距使得連續彻彳器元件料之間 的角分離大約為0.004。。 反射輻射之振盪圖案之週期，如曲線％所示，在大約 0.007與大約〇.01〇。之間變化，其接近於陣列^的 極限因此，曲線54未能捕獲曲線56中所出現的一部分真 實振盪結構，並且重製出具有低保真度之其他部分結構。 另一方面，當組合多個測量時，在其他測量中成功地捕獲 在曲線54中未出現的振I结構部分。結果，如曲線56所示， 陣列32的有效解析度得以加強^以此方式所獲得的加強可 使解析度實際上比用於在陣列32±成形振㈣案的χ射線 光學元件的解析度更精細。如上所述，將理論模型擬合成 曲線56，以便決定若干參數，例如樣品22上表面層之厚度 與表面品質。因為XRR信號本質上係複雜的，並且展示與 角度成函數關係的非線性頻_變化，故藉由上述方式偏移 陣列所獲得之新增資料點有助於改善擬合，因而擷取更為 準確的表面層參數值。 現在參考圖5A與5B，其根據本發明一具體實施例示意性 96959.doc -24. Ϊ345055 δ兄明一種用於決定樣品22之零角的方法。圖5a係系統2〇之 一示意側視圖’說明在不同的系統條件下由χ射線源26所產 生並且入射於陣列32上的χ射線光束之角展度。由陣列32 在此等不同條件下所偵測到的光束之角特性係用於決定樣 品22的零角。本文中術語「零角」係用以指在χ射線光束入 射於樣品上的點處切線與樣品22之表面所成的仰角。此零 角等效於圖3所示光譜中的上述零點。然而，與用於在此等 光譜中找到零點的上述方法不同，圖5入與5Β所述方法不依 賴於樣品22上任何特定的層結構類型。本文中藉由識別與 樣品22之切線對準的陣列32之偵測器元件而找到零角（或 在藉由上述解析度加強技術所建立的虛擬陣列中，藉由找 到與此切線對準的虛擬像素）。 圖5 Α顯示四個不同的光束組態： •一狹窄的反射光束55,其係當樣品22放在適當的位置並 且擋板3 8係放置成切斷光束的低角度部分時入射於陣列 3 2上，如圖所示。 •一寬反射光束57，其大致向下延伸至樣品22的零角，並 且此時將撐板38從光束撤出。 狹乍的直接光束58 ’當從χ射線光束路徑移除樣品22 時，其係'入射於陣列32上（故無反射光束），而擋板⑽ 次置放成切斷光束之低角度部分。 寬直接光束59，其向上延伸至光束57的零角，通常甚 至延伸超出此零角，並且此時將擋板與樣品從乂射線光束 移除。 96959.doc •25- 1345055 應注意，在零角附近，P車列32所捕獲的信號（起因於光束 57)不具有明顯的切斷，而是逐漸地並且不完全光滑地增加 。（為簡化起見，圖3中未顯示此逐漸增加。）因此，難以僅 根據此信號決定零角。 圖5B係陣列32在由光束55、57、柳娜射之情況下所 作測量結果的示意曲線圖。該等結果係針對水平（角幻轴上 的每個像素而計算成由其中一個狹窄光束引起的像素強度 值對由一對應的寬光束引起的值之比，即比率= inarr〇w/ibroad。藉由計算當光束58入射於陣列32上時所測 量的每個像素值與當光束59入射時所測量的值之比，而產 生曲線圖的左分支61(對於零角以下的仰角）。藉由當光束^ 入㈣陣列上時所測量的每個像素值與當光束5认射時所 測量的值之比’而提供右分支63(對於零角度以上的仰角卜 如圖’正與負角度的比率在零角度附近通常為 零’因為撞板38切斷此角度範圍中的光束55與58»比率在 零以上按-切割角度增加，大致對應於擋板％攔截X射線光 束的角度彡漸增加至大約為一的值遠離擋板邊緣一角 度。分支6#63往往係光滑的曲線，因為由狭窄光束引起 的的強度值局部變化通常係藉由因寬光束引起的強度值對 應變化而抵消。因此，可藉由在百分之五十的點65(此時的 強度比為0.5)之間取平均角而準確地求出零角。或者，可將 曲線擬。程序應用於分支61與63，並且可使用擬合參數來 求出零角。擋板38的角位置係由點65之間的角距離的一半 給疋。作為另一替代方案，曲線63可關於水平轴上的一點 96959.doc -26- 1345055 而鏡射，故其與曲線61重疊。提供兩條曲線之間最佳重疊 的鏡射點係被識別為零角。 圖5Α與5Β所例示的方法可用於找到樣品22之表面上實 質上任何點處的零角，獨立於樣品的性質以及樣品上某些 類型之表面層的存在與否。此用於找到零角的方法特別有 用，例如，在趨向於彎曲的半導體晶圓中的χ射線反射量測 中，其中半導體晶圓彎曲會使零角在晶圓的表面上變化。 該方法保持有效，即使入射χ射線光束不均勻，並且不論反 射光朿中的任何角變化（只要反射率與角度成函數而持續 變化）。可將此方法與以上參考圖2至4所述的解析度加強方 法組合（其中在陣列32的不同位置獲取信號），以便決定具有 更高準確性的零角度。 本方法的另一優點係’其可結合實際的XRR測量予以實 施，實質上不會中斷測量程序。當系統2〇中缺少樣品。時 了進行直接光束5 8與5 9的測量，通常在不同樣品的測量之 間。可使反射光束55與57的測量與XRR測量平行。例如， 當樣品的表面層密度大於約15 g/cm3時，使用大約〇 15。與 4°之間的角度範圍進行XRR分析，而使用〇。與〇15。之間的 範圍來進行零角度校準。 為獲取用於建立（例如）分支63的資料，將擋板38提前， 以便切斷X射線光束之低角度部分（低於大約〇·丨。），並且在 大約1至2秒的曝光時間期間從陣列32獲取反射信號。然後 撤回擋板，並且從該陣列獲取另一反射信號。可與曝光時 間在兩個擋板位置的比率來正規化信號。可計算正規化曲 96959.doc -27- 線的比率來求出分支⑴使用類似的程序來產生分支6卜 ，圖6係根據本發明一具體實施例，用於半導體元件製造的 群集工具70的示意俯視圖。群集工具包含多個纟，包括一 ，尤積台72 ’用於將薄膜沈積於—半導體晶圓77之上； —。74，以及其他在本技術中熟知的台76，例如一清潔台。 構建榀查台74，並使其以類似於系統2〇的方式運作，如上 斤述 自動機械78在系統控制器80的控制下於台72、 76 ...之間轉移晶圓77。工具70的操作可藉由一操作 員使用耦合至控制器80的工作台82來控制與監視。 在生產程序中藉由沈積台72與工具70中的其他台所實施 的選定步驟之前與之後，使用檢查台74藉由乂^^來執行晶 圓的X射線檢查。在一示範性具體實施例中，使用沈積台72 在b曰圓77上形成多孔薄膜，例如多孔低k介電層，並且檢查 。74執行xrr評估，如上所述。此配置允許使用控制器肋 以及可能還有工作台8 2較早地偵測程序偏差以及方便地調 整與评估生產晶圓上的程序參數。用於找到零角以及加強 谓測解析度的上述方法亦可用於檢查台74。 圖7係根據本發明另一具體實施例，用於半導體晶圓製造 以及原地檢查的系統9〇之示意側視圖。系統9〇包含一真空 室92 ’其包含沈積裝置94以用於在晶圓77上形成薄膜，此 點在此項技術中係熟知的。將晶圓安裝於室92内的移動級 24。該室通常包含X射線窗口 96，其可能屬於上述專利申請 公開案US 2001/0043668 Α1中所述的類型。X射線源26以上 述方式經由其中一個窗口 96照射晶圓77上的區域28。為簡 96959.doc -28 · 1345055 /繁起見，圖7令省略圖〗所示的擋板、刀口與狹縫，但一般 而曰，會將此種元件併入χ射線源26或室92之内。 。藉由偵測器組件3〇中的陣列32經由另一個窗口 ％接收從 區域28反射的Χ射線。處理器40從偵測器組件30接收信號， 並處理信號’以便評估在室92内之生產中薄膜層的特性。 此評估之結果可用於控制沈積裝置94，使系統㈣產生的 薄膜具有所需的特性，例如厚度、密度與孔隙率。用於找 到零角以及加㈣測解析度的上述技術亦可用於室％。 儘Β上述具體實施例主要涉及決定半導體晶圓上低让介 電層的孔隙率特性’但本發明的原理可同樣用於其他的乂 射線反射量測應用以及其他類型之基於輕射的分析 中’不僅使用X射線，而且還使用其他離子化的輕射帶。因 此應明白，可以藉由範例引用上述具體實施例，及應明 本發明並不限於以上特別顯示及說明的内容。而是， 本發月的範V包括上述各種特色的組合及附屬組合，以及 熟習本技術者在讀完上述說明後，對本發明所想到之先前 技術所未揭露的變化及修改。 【圖式簡單說明】 圖1係根據本發明一具體實施例用於x射線反射量測 (XRR)測量之系統之示意側視圖； 圖2係根擄本發明一具體實施例而配置用於X R R的偵測 器陣列之示意正視圖； 圖3係根據本發明一具體實施例之X R R測量的示意曲線 圖； 96959.doc -29- 1345055 圖4係根據本發明一具體實施例之xrr測量的示意曲線 圖，其说明用於獲取具有次像素解析度之XRR光譜的方法； 圖5A係根據本發明一具體實施例之圖丨之系統的示意側 視圖，其說明系統中擋板與樣品之不同組態中藉由X射線光 束所對向的角度； 圖5B係根據本發明一具體實施例之χ射線測量結果之示 意曲線圖，該結果用於決定χ射線入射於圖5A所示系統中 的樣品上之零角； 圖6係根據本發明一具體實施例用於半導體元件製造且 包括檢查台的群集工具的示意俯視圖；以及 圖7係根據本發明一具體實施例具有χ射線檢查能力之半 導體處理室之示意側視圖。 【主要元件符號說明】 20 系統 22 樣品 24 動作級 26 X射線源 27 會聚光束 28 小區域 29 反射光束 30 偵測器組件 32 偵測器陣列 33 平移元件 34 窗口 96959.doc 1345055 36 刀口 38 擋板 39 狹缝 40 信號處理器 42 分佈 45 垂直位置 46 偵測器元件 47 垂直位置 50 曲線 52 曲線 54 曲線 56 曲線 55 狹窄的反射光束 57 寬反射光束 58 狭窄的直接光束 59 寬直接光束 61 左分支 63 右分支 65 點 70 群集工具 72 沈積台 74 檢查台 76 其他台 77 半導體晶圓 96959. doc -31 - 1345055 78 自動機械 80 系統控制器 82 工作台 90 系統 92 真空室 94 沈積裝置 96 X射線窗口 96959.doc -32·Fixed cut-off angle / S: +77 IA radiation from the surface of the sample reflected from the surface of the sample to the radiation detector; and a signal processor, Ganzi singer eight series lightly combined to be the first direct The first-to-one first reflected signal between the signal and the second straight signal is compared with the second ratio of the second reflected signal of 96959.doc -16 - 1345055 to obtain the elevation angle formed by the tangent to the surface. It should be understood that the "first" and "second" in the above and the scope of the patent application are used arbitrarily. Thus, for example, such terms do not necessarily reflect the actual order in which the above signals are received. The invention will be more fully understood from the following detailed description of embodiments of the invention. [Embodiment] Reference is now made to Fig. 1 ' which is a schematic side view of a system 2 for ray ray reflectometry (XRR) in accordance with an embodiment of the present invention. The system 2 is similar to the further 1111 system described in the above-mentioned U.S. Patent No. 6,512,814, but with the addition of the features and capabilities described herein. A sample 22 to be evaluated by system 20, such as a semiconductor wafer, is mounted on a moving stage 24 to enable accurate adjustment of the position and orientation of the sample 22. An X-ray source 26, typically an X-ray tube with suitable monochromating optical elements (not shown), illuminates a small area 28 on the sample 22. For example, an XTF5011 X-ray tube manufactured by Oxford Instruments (Sc〇tts Valley, Calif.) can be used for this purpose. The optical element focuses the radiation from the X-ray tube onto region 28 in a converging beam 27. U.S. Patent No. 6,381,303, the disclosure of which is incorporated herein by reference in its entirety in its entirety, the entire disclosure of the disclosure of the disclosure of the disclosure of the disclosure of the disclosure of the disclosure of For example, the optical component can comprise a curved crystal monochromator, such as a focused double-bending optical component produced by XOS Corporation of Albany, New York. Other suitable optical components are described in the above-mentioned U.S. Patents 5,619,548 and 5,923'720. Those skilled in the art will appreciate other possible optical configurations. The amount of reflection in system 2 96 96959.doc 17 1345055 The typical X-ray energy system for measurement and scatterometry is approximately 8.05 keV (CuKal). Alternatively, other energies may be used, such as 5.4 keV (CrKal). The use of a dynamic knife edge 36 and the baffle 38 limits the angular extent of the X-ray incident beam 27 in the vertical direction (i.e., perpendicular to the plane of the sample 22), while a slit 39 can be used to limit the beam in the horizontal direction. The knife edge, the baffle and the slit together serve as a baffle assembly for adjusting the lateral dimension of the beam 27. 1 is an illustration of a configuration of a baffle assembly. An alternative configuration of an X-ray optical component for controlling the lateral dimension of the beam 27 in the following manner will be apparent to those skilled in the art and is considered to be within the scope of the present invention. Within the scope of this. The use of the knife edge 36 and the baffle 38 in the 乂1111 measurement is described in detail in the above-mentioned U.S. Patent No. 6,512,814. In short, to best detect close to zero. The low angle reflection ' removes the baffle 38 out of the range of the incident beam 27, placing the knife edge 36 over the area 28' and lowering it to reduce the effective vertical section of the beam. The result 'can reduce the lateral dimension of the X-ray spot incident on the region 28. On the other hand, to effectively detect the weaker, higher angle reflection, the knife edge 36 is withdrawn from the beam 27, and the baffle 38 is removed. Placed to cut off the low angle portion of the beam. (Or 'place the baffle to cut the low angle portion of the reflected beam 29 y.) In this way 'only high angle reflections from sample 22 (rather than stronger low angle reflections) can reach the detector array. Thus the signal/background ratio of the high angle measurement is enhanced. In the xRR measurement, the slit 39 is typically open to accept the solid cone of converging rays, thereby increasing the signal/noise ratio of the reflectance measurement. The X-ray reflected beam 29 reflected from the sample 22 is collected by the 彳贞's assembly 30. As for the XRR, the assembly 30 collects the range of reflection angles in the vertical (elevation angle - Φ) direction 96599.doc -18 - 1345055. About 〇. With 3. Between the reflected x-rays, these angles are above and below the critical angle of the total external reflection of the sample. (The angles shown in the figures are exaggerated for clarity of illustration, such as the elevation angle of the x-ray source 26 and the detector assembly 30 on the plane of the sample 22 in FIG. 1.) The assembly 30 includes a detector array 32, For example, a ccd array, as described below. For the sake of brevity, only a single column of detector elements is shown in the ®, there are a relatively small number of _ elements, and (4) columns 32 generally include a larger number of components configured as a linear array or a matrix (two Dimension) array. The assembly may include a translating member 33 of any suitable type well known in the art for offsetting and aligning the array 32 relative to the sample 22. Component 3 further includes a window 34' that is made of a suitable X-ray transparent material (e.g., wrinkles) spaced from the front of the detector array and between the array and the sample. Further details of the operation of array 32 are described below with reference to FIG. The k processor 40 analyzes the output of the component 30 to determine the flux distribution 42 of the X-ray photons reflected from the sample 22 based on the angle for a given energy or within an energy range. In general, sample 22 has one or more thin surface layers 'e.g., a thin film in region 28 such that distribution 42 as a function of elevation angle exhibits an oscillating structure' which is caused by reflection from the interface between the layers. Interference effects between X-ray waves. Processor 40 analyzes the angular distribution characteristics using the analytical methods described below to determine characteristics of one or more surface layers of the sample, such as layer thickness, density, and surface quality. 2 is a schematic elevational view of array 32 in accordance with an embodiment of the present invention. The array 32 shown in this figure includes a single column of detector elements 46 having an array of axes aligned along an axis that is perpendicular to the plane of the sample 22. Element 46 has a high aspect ratio 96959.doc • 19-1345055 ratio, i.e., its width in the direction across the array axis is substantially greater than its distance along the axis. The high aspect ratio helps to enhance the signal/noise ratio of the system 2 because the array 32 can thereby collect X-ray photons in a relatively wide area for each angular increment along the axis of the array. However, only the dimensions of element 46 are illustrated in the figures, and the principles of the present invention can be applied using smaller or larger aspect ratio elements depending on the application needs and the availability of the appropriate detector elements. As noted above, array 32 can comprise a linear CCD array or a matrix array, such as the s7〇32 i〇〇8 array produced by Hamamatsu Corporation of Hamamatsu, Japan. The latter array contains 1044 x 256 pixels and the overall size is 25_4 x 6 mm. It can operate in a line_binning mode in which special hardware provided by H_matsu/Av for this purpose is used, so that multiple detector elements in each column of the array are effectively used as having high aspect A single component. In this case, although array 32 physically contains a two-dimensional matrix of detector elements, functionally, the array takes the form of a single column of detector elements, as shown in FIG. Or 'array 32' can include a piN diode array with suitable readout circuitry, possibly including integrated processing electronics, as described in U.S. Patent No. 6,389, the disclosure of which is incorporated herein by reference. The way is incorporated herein. This patent also describes alternative features of the array 'including various geometric configurations of the array and two dimensions" and masks that can be used to enhance the detection properties of the array. These features also apply to the components of this patent application. In any case, it should be understood that only the detector types are exemplified here, and any suitable type, size and number of detectors can be used. In the aspect of the invention, as shown in Fig. 2, the array 32 is offset by a small increment, for example, using a translation element Μ (Fig. 96959.doc • 20· 1345055 1)~Z direction. The figure shows the two vertical positions 45 and 47 of the array 32, which are separated by an increment in the Z direction, i.e., half the array pitch, i.e., half of the center-to-center separation of the detector elements 46. (Although positions 45 and 47 are horizontally offset as shown in Figure 2, the horizontal offset is used in this figure for clarity only and is not necessary or required for XRR measurements). X-ray source 26 is driven in each of positions 45 and 47, and assembly 30 captures the X-rays reflected from sample 22 as a function of elevation. The component 3 can operate in this manner to capture x-rays in more than two different vertical positions, typically with a small increment in the x direction between the positions. For example, three different locations separating the array spacing can be used. The signals produced by component 30 at each of the different vertical positions are input to processor 40, which combines the readings taken at different locations into a single spectrum. Essentially, the processor produces a "virtual array" with a lower resolution than the actual physical array 32. The letter 35 in the virtual array can be derived, for example, by simply reading the readings taken at different array locations by interleaving. Because, for each "virtual pixel" in the virtual array, the processor 4 selects the measured value of the real pixel of the corresponding position in one of the actual measurements, so that the readings obtained at different measurement positions are from one virtual pixel to the next. A virtual pixel alternates. In other words, assume that the following read pixel readings are obtained at three consecutive positions of the array: Position 1: R11, R21, R31, R41, ... Position 2: R12, R22, R32, R42, ... Position 3: R13, R23, R33, R43, the resulting virtual array will contain the following values at the virtual element separating 1/3 of the actual array spacing: 96959.doc -21 - 1345055 R11, R12, R13, R21, R22, R23, RM, R32, R33, R41, ... Alternatively, other methods can be used, such as the difference or reading of readings at different array locations to capture X-shaped information from individual actual measurements before combining readings' or by selecting each of the virtual arrays to be used The actual measurement of the pixel. The resolution enhancement technique described above is particularly useful when the XRR spectrum has a fine structure with a high spatial frequency. Therefore, the stripe separation is equivalent to or smaller than the array pitch. Or 'when the XRR spectroscopy is strong enough and the fringes are clearly separated, it is sufficient to measure the XRR signal for a single singular: $#, early field straight position (eg, position 45) to capture an acceptable spectrum. Figures 3 and 4 are unintentional graphs of the XRR measurements made using the system 2〇 in accordance with the present invention. Such a graph can be generated using signals received at a single vertical position of the array, or by combining two or more signals at different vertical positions as described above. The graph of Figure 3 shows the intensity of the reflected x-rays received by the array 32 at a single vertical position as a function of the elevation angle, wherein 乂α (8.〇5"^ radiation from the xenon source 26 is used. Figure 4 shows the results of combining the signals captured at a plurality of different vertical positions of the array 32. The upper curve 50 shows the reflection measured from the bare wafer, and the lower curve 52 shows the low k formed therefrom. The reflection of the wafer of the porous dielectric film. Both curves have a shoulder, located at an angle marked as ^ in the figure, slightly larger than 0.2. This angle corresponds to the critical angle from the total external reflection of the 矽. More precise For the standard tantalum wafer with a density of 2.33 g/cm3, the critical angle of 8.〇5 keV is 0.227. Therefore, once the position of the shoulder at φ2 is found, only 96599.doc •22- 1345055 needs to be Φ2. The left side of the reverse is 0.227. The zero point of the spectral angle (horizontal) of the spectrum of Figure 3 can be accurately determined. The angular scale of each detector element 46 (in degrees) is 71 Vfocal dist J π U〇cal dist medium focal length from the focal zone 28 to the distance of the array 32. In the alternative or in addition, the method described in the above-mentioned U.S. Patent Application Serial No. 1/313,28, the use of the shoulder at <h, but without reference to the array spacing and Focal length, fully calibrated angular scale. Above the critical angle, curve 52 shows an oscillating structure, mainly due to reflection from the upper and lower surfaces of the low-k film. The period and amplitude of this oscillation can be analyzed to determine the crystal. The thickness and surface quality of the film on the circle (and possibly other film layers). For example, a fast Fourier transform can be used to extract the relevant characteristics of the oscillation. Alternatively, a parametric curve fitting method can be used to determine the film more accurately. The method for analyzing the XRR signal, such as curve 52, is described in more detail in the above-mentioned U.S. Patent No. 6,512,814. Thus, the position of the shoulder in the critical angle and the reflection curve is primarily determined by the density of the material that reflects the X-rays. Since the porous, low-k dielectric layer deposited on the wafer has a density substantially lower than that of the germanium substrate, the critical angle of the porous layer is substantially lower than the critical angle of the lower crucible Thus, another shoulder is seen in curve 52, located at a smaller angle labeled φι in the figure, corresponding to the critical angle of the porous layer. The known value of Φ2 can be used, depending on the calibration of the angular scale described above. The actual value of the porous material can be determined with high accuracy based on the calibration value of the crucible. Since the intrinsic density of the dielectric material (in the case of no pores) is generally known, The total volume of the pores, the per unit volume of the porous layer, can be derived from the difference between the known intrinsic density of the dielectric material and the estimated overall density of the porous layer by the difference of 965.9.doc • 23·1345055. Figure "The reflection of the shoulder not affected by the array 32 as a function of the elevation angle Φ. X-ray = intensity' indicates that multiple measurements will be made at different vertical positions of the array. The angular scale in this figure is relative to that in Figure 3. The angular scale is expanded. The original curve 54 shows a typical measurement of the single-vertical position of the array 32. The combination curve 56 shows the results obtained by combining five measurements made at different vertical positions of the array. The two directions are offset from each other by ι/5 歹J spacing. The spacing of the arrays is such that the angular separation between the successive device elements is approximately 0.004. The period of the oscillating pattern of reflected radiation is as shown by curve % , varying between approximately 0.007 and approximately 〇.01〇, which is close to the limit of the array ^. Thus, curve 54 fails to capture a portion of the true oscillating structure present in curve 56 and is reproduced with low fidelity Other partial structures. On the other hand, when a plurality of measurements are combined, the portion of the vibrational I structure that does not appear in the curve 54 is successfully captured in other measurements. As a result, as shown by the curve 56, the effective resolution of the array 32 The enhancement obtained in this way can make the resolution actually finer than the resolution of the x-ray optical element used in the array 32±formed vibration (4) case. As described above, the theoretical model is fitted to the curve 56, In order to determine a number of parameters, such as the thickness of the surface layer on the sample 22 and the surface quality. Since the XRR signal is inherently complex and exhibits a nonlinear frequency-variation as a function of angle, it is obtained by offsetting the array in the manner described above. The addition of data points helps to improve the fit and thus captures more accurate surface layer parameter values. Referring now to Figures 5A and 5B, an exemplary 96695.doc -24. Ϊ345055 δ brother is illustrated in accordance with an embodiment of the present invention. A method for determining the zero angle of the sample 22. Figure 5a is a schematic side view of the system 2' illustrating the x-ray beam produced by the x-ray source 26 and incident on the array 32 under different system conditions. Angular spread. The angular characteristics of the beam detected by array 32 under these different conditions are used to determine the zero angle of sample 22. The term "zero angle" is used herein to refer to incident ray beam. The elevation angle at which the tangent at the point on the sample is at the surface of the sample 22. This zero angle is equivalent to the above zero in the spectrum shown in Figure 3. However, unlike the above methods for finding zeros in such spectra, the methods described in Figures 5 and 5 are independent of any particular layer structure type on sample 22. The zero angle is found herein by identifying the detector elements of the array 32 aligned with the tangent to the sample 22 (or in the virtual array created by the resolution enhancement technique described above, by finding alignment with this tangent Virtual pixel). Figure 5 shows four different beam configurations: • A narrow reflected beam 55 that is incident on the array 3 when the sample 22 is placed in position and the baffle 38 is placed to cut off the low angle portion of the beam. 2, as shown. • A wide reflected beam 57 that extends generally downwardly to the zero angle of the sample 22 and at this point withdraws the riser 38 from the beam. The narrow direct beam 58' when the sample 22 is removed from the x-ray beam path, is 'injected onto the array 32 (so no reflected beam), and the baffle (10) is placed second to cut off the low angle portion of the beam. A wide direct beam 59, which extends upwardly to the zero angle of beam 57, typically extends even beyond this zero angle, and at this point removes the baffle and sample from the x-ray beam. 96959.doc •25– 1345055 It should be noted that near the zero angle, the signal captured by the P train 32 (due to the beam 57) does not have a significant cut, but gradually and not completely smoothly. (This gradual increase is not shown in Figure 3 for the sake of simplicity.) Therefore, it is difficult to determine the zero angle based only on this signal. Figure 5B is a schematic plot of the measurement results of array 32 in the case of beams 55, 57, and Liu Na. These results are calculated for the horizontal (each pixel on the angular phantom axis is calculated as the ratio of the pixel intensity value caused by one of the narrow beams to the value caused by a corresponding wide beam, ie, ratio = inarr 〇 w / ibroad. The left branch 61 of the graph (for elevation angles below zero angle) is generated by calculating the ratio of each pixel value measured when the beam 58 is incident on the array 32 to the value measured when the beam 59 is incident. The right branch 63 is provided by the ratio of each pixel value measured when the beam is incident on the (four) array to the value measured when the beam 5 is incident (for elevation angles above zero angle, as shown in the figure 'positive and negative angles' The ratio is usually zero near the zero angle 'because the striker 38 cuts the ratio of the beam 55 to 58» in this range of angles above the zero-cut angle, roughly corresponding to the angle at which the baffle intercepts the X-ray beam. Increasing the value to approximately one away from the edge of the baffle. Branch 6#63 tends to be a smooth curve because local variations in intensity values caused by narrow beams are usually offset by corresponding changes in intensity values due to wide beams. . Therefore, the zero angle can be accurately obtained by taking an average angle between the fifty-fifth point 65 (the intensity ratio at this time is 0.5). Alternatively, the curve can be applied to the branches 61 and 63. And the fitting parameters can be used to find the zero angle. The angular position of the baffle 38 is given by half the angular distance between the points 65. As a further alternative, the curve 63 can be about a point 96599 on the horizontal axis. Doc -26- 1345055 and mirrored, so it overlaps with curve 61. The mirror point that provides the best overlap between the two curves is identified as a zero angle. The methods illustrated in Figures 5 and 5 can be used to find sample 22 The zero angle at virtually any point on the surface, independent of the nature of the sample and the presence or absence of certain types of surface layers on the sample. This method for finding zero angles is particularly useful, for example, in semiconductor crystals that tend to bend In the measurement of x-ray reflection in a circle, where the bending of the semiconductor wafer causes the zero angle to vary across the surface of the wafer. This method remains effective even if the incident x-ray beam is not uniform and regardless of any angular variation in the reflected pupil (as long as the reflectivity and angle The function continues to change.) This method can be combined with the resolution enhancement method described above with reference to Figures 2 through 4 (where signals are acquired at different locations of the array 32) to determine a zero angle with higher accuracy. Another advantage is that it can be implemented in conjunction with actual XRR measurements, without substantially interrupting the measurement procedure. When the sample is missing from the system 2, the direct beam 5 8 and 5 9 are measured, usually in different samples. Between measurements, the measurement of reflected beams 55 and 57 can be made parallel to the XRR measurement. For example, when the surface layer density of the sample is greater than about 15 g/cm3, XRR analysis is performed using an angular range of approximately 〇15. While using a range between 〇 and 〇 15, to perform a zero angle calibration. To obtain data for establishing, for example, branch 63, the baffle 38 is advanced to cut off the low angle portion of the X-ray beam (below approximately 〇·丨.) and during an exposure time of approximately 1 to 2 seconds A reflected signal is acquired from array 32. The baffle is then withdrawn and another reflected signal is taken from the array. The signal can be normalized to the ratio of the exposure time at the two baffle positions. The ratio of the regularized curve 96599.doc -27-line can be calculated to find the branch (1) using a similar procedure to generate the branch 6b, which is a cluster tool 70 for semiconductor component fabrication in accordance with an embodiment of the present invention. Show the top view. The cluster tool includes a plurality of germanium, including one, a stacker 72' for depositing a thin film on the semiconductor wafer 77; 74, and other stations 76 that are well known in the art, such as a cleaning station. The inspection station 74 is constructed and operated in a manner similar to the system 2, as described above. The robot 78 transfers the wafer 77 between the stages 72, 76, ... under the control of the system controller 80. The operation of tool 70 can be controlled and monitored by an operator using a table 82 coupled to controller 80. X-ray inspection of the wafer is performed by the inspection station 74 before and after the selected steps performed by the deposition station 72 and the other stations in the tool 70 in the production process. In an exemplary embodiment, a porous film, such as a porous low-k dielectric layer, is formed on b-circle 77 using deposition station 72 and inspected. 74 performs an xrr evaluation as described above. This configuration allows the use of controller ribs and possibly also the workbench 8 2 to detect program deviations earlier and to conveniently adjust and evaluate program parameters on the production wafer. The above method for finding the zero angle and enhancing the resolution of the sense can also be used for the inspection station 74. Figure 7 is a schematic side elevational view of a system for semiconductor wafer fabrication and in situ inspection, in accordance with another embodiment of the present invention. System 9A includes a vacuum chamber 92' which includes deposition means 94 for forming a film on wafer 77, as is well known in the art. The wafer is mounted to the mobile stage 24 within the chamber 92. The chamber typically comprises an X-ray window 96, which may be of the type described in the aforementioned patent application publication US 2001/0043668 Α1. X-ray source 26 illuminates region 28 on wafer 77 via one of the windows 96 in the manner described above. For the sake of Jane 96599.doc -28 · 1345055 / see Fig. 7, the baffles, edges and slits shown in the figure are omitted, but in general, such elements will be incorporated into the x-ray source 26 or chamber 92. within. . The x-rays reflected from region 28 are received by array 32 in detector assembly 3 via another window %. Processor 40 receives signals from detector assembly 30 and processes the signals ' to evaluate the characteristics of the film layers in the production within chamber 92. The results of this evaluation can be used to control the deposition apparatus 94 to provide the film produced by the system (4) with desired characteristics such as thickness, density and porosity. The above technique for finding the zero angle and adding the (four) measurement resolution can also be used for the room %. While the above specific embodiments are primarily concerned with determining the porosity characteristics of a low dielectric layer on a semiconductor wafer, the principles of the present invention are equally applicable to other xenon ray reflection measurement applications and other types of light-based analysis. 'Not only using X-rays, but also using other ionized light shots. It is to be understood that the specific embodiments are described by way of example, and that the invention is not limited to what is particularly shown and described. Rather, the present invention includes variations and modifications of the various features described above, as well as variations and modifications of the prior art that are apparent to those skilled in the art after reading the foregoing description. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic side view of a system for x-ray reflectance measurement (XRR) measurement in accordance with an embodiment of the present invention; FIG. 2 is configured for XRR according to an embodiment of the present invention. Figure 3 is a schematic diagram of XRR measurement in accordance with an embodiment of the present invention; 96959.doc -29- 1345055 Figure 4 is a schematic representation of xrr measurement in accordance with an embodiment of the present invention a graph illustrating a method for obtaining an XRR spectrum having sub-pixel resolution; FIG. 5A is a schematic side view of a system in accordance with an embodiment of the present invention, illustrating a different set of baffles and samples in the system FIG. 5B is a schematic diagram of the measurement results of x-rays according to an embodiment of the present invention, the result being used to determine the sample in which the x-ray is incident on the system shown in FIG. 5A. FIG. 6 is a schematic plan view of a cluster tool for fabricating a semiconductor device and including an inspection station in accordance with an embodiment of the present invention; and FIG. 7 is a diagram of a cluster according to an embodiment of the present invention. A schematic side view of a semiconductor processing chamber of the line inspection capability. [Main component symbol description] 20 System 22 Sample 24 Action level 26 X-ray source 27 Converging beam 28 Small area 29 Reflected beam 30 Detector component 32 Detector array 33 Translation element 34 Window 96599.doc 1345055 36 Knife edge 38 Baffle 39 Slit 40 Signal Processor 42 Distribution 45 Vertical Position 46 Detector Element 47 Vertical Position 50 Curve 52 Curve 54 Curve 56 Curve 55 Narrow Reflected Beam 57 Wide Reflected Beam 58 Narrow Direct Beam 59 Wide Direct Beam 61 Left Branch 63 Right branch 65 points 70 Cluster tool 72 Deposition station 74 Inspection station 76 Other station 77 Semiconductor wafer 96759. doc -31 - 1345055 78 Automated machine 80 System controller 82 Table 90 System 92 Vacuum chamber 94 Deposition device 96 X-ray window 96959 .doc -32·