A7 五、發明說明（4 ) 補充 (1999年9月修正） 度、180度、270度和360度的五個相位偏移的干涉圖的數 位化光強度依下列公式算出該相位函數： 0 = tan' (請先閲讀背面之注意事項ΐ&本頁： 2(/2~/4) 式中I!，12 ’ 13，14及15代表該干涉圖的某一點的數位化光 強度，及 Φ爲該點的相位。 較佳的，該步驟e)的相對高度係依下式算出： 相對高度=·^^(Φ,-Φε) 4/Γ 式中Φ,爲基板上半徑r處一點的相位，及 Φ,爲基板上中心點的相位。 較佳的，該步驟i)的光源爲雷射光或經一狹縫所產生 的狹縫光源。 Φ 發明詳細說明 經濟部智慧財產局員工消費合作社印製 量測沈積後和沈積前基板彎曲量的差異，而獲得薄膜 應力，此爲量測薄膜應力的一種方法，此方法的最大關鍵 在於如何決定沈積後和沈積前基板彎曲量的差異，過去有 使用顯微鏡放大刻度決定彎曲量差異，但放大倍率仍然不 夠，所獲得彎曲量較不準確。也有使用干涉條紋數目的變 化決定彎曲量差異，但因條紋本身有寬度且需人工量測計 算條紋數目變化，較不客觀，也就較不準確。也有導入雷 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） A7 ____ _______B7_ 五、發明说明（1 ) 發明背景 薄膜應力屬於薄膜力學性質的一種，可分爲伸張應力 和壓縮應力。從巨觀的觀點論起，薄膜應力使被沈積的基 板彎曲，伸張應力將使該基板形成凹表面，而壓縮應力將 使基板形成凸表面*當薄膜應力過大時，造成薄膜和基板 界面間的剝落或形成過多的空洞和裂縫，不利於沈積的最 大膜厚度、膜層堆疊結構、光學薄膜和半導體薄膜的膜質 特性，因此在薄膜製鍍工業裏，薄膜應力是製程考慮的重 要因素，相對地，決定薄膜應力大小的量測方法也就非常 地重要。 由於薄膜應力將使被沈積基板彎曲，如能在薄膜附著 基板後，量測該基板的彎曲程度，就可求出薄膜應力大小。 目前量測薄膜應力大小的方式，大都就是利用上述的物理 原則，而最大的差異在於使用什麼方式決定基板因薄膜附 著後的彎曲量大小，例如，使用顯微鏡觀測彎曲量的大小 或觀察干涉條紋的數目差代表干涉條紋的變化量來計算基 板因薄膜附著後的彎曲量大小，不過以這些方法決定的基 板彎曲程度基板彎曲量的大小較不準確，因爲必須使用較 大刻度配合人爲判斷方式量測彎曲量。另外一個方法是導 引雷射光打在基板上，量測基板的曲率半徑推算基板彎曲 大小，不過由於需一點一點地計算基板彎曲量，才能獲得 基板整面彎曲量，在量測速度上較慢。 由於1C的微小化趨勢，使得薄膜在基板上的沈積厚度 愈來愈薄直到微米級。在此種趨勢下，薄膜沈積所造成的 本紙张尺度述州中囤國家標率（C:NS ) A4規格（210X297公釐） 五、發明說明（6 ) (1999年9月修正) ;修正 本W年，甩 丨補充 Φ = tan' (請先閱讀背面之注意事項本頁) 2(12~h) 2/3-/5-Λ 其中Φ爲該點的相位函數，^至^代表五張干涉圖該點的 數位化強度，而求出的相位函數則可代表待測面的輸廓 圖。因爲薄膜有應力，故沈積在基板上會使基板彎曲，假 設薄膜應力爲各向同性（isotropic)，可以藉著薄膜沈積前 和沈積後測量基板彎曲量（相對高度）的差値，代入下列公 式計算膜應力A7 V. Description of the invention (4) Supplement (corrected in September 1999) The digitized light intensity of the interferograms with five phase shifts of degrees, 180 degrees, 270 degrees, and 360 degrees is calculated according to the following formula: 0 = tan '(Please read the precautions on the back ΐ & this page: 2 (/ 2 ~ / 4) where I !, 12' 13, 14, and 15 represent the digitized light intensity at a certain point of the interferogram, and Φ Is the phase of the point. Preferably, the relative height of step e) is calculated according to the following formula: Relative height = · ^^ (Φ, -Φε) 4 / Γ where Φ is a point at a radius r on the substrate Phase, and Φ, is the phase of the center point on the substrate. Preferably, the light source in step i) is laser light or a slit light source generated through a slit. Φ The invention explains in detail that the consumer cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs prints and measures the difference in the amount of bending of the substrate after deposition and before deposition, and obtains the film stress. This is a method for measuring film stress. The key to this method is how to determine The difference between the amount of bending of the substrate after deposition and that of the deposition before. In the past, the difference in the amount of bending was determined using a microscope magnification scale, but the magnification was still insufficient, and the obtained amount of bending was less accurate. There are also variations in the amount of interference using the number of interference fringes, but because the fringe itself has a width and requires manual measurement to calculate the number of fringes, it is less objective and less accurate. There are also imported Raman paper sizes that apply Chinese National Standard (CNS) A4 specifications (210 X 297 mm) A7 ____ _______B7_ V. Description of the invention (1) Background of the invention Film stress is one of the mechanical properties of the film and can be divided into tensile stress and compression stress. From a macro perspective, the film stress causes the substrate to be bent, the tensile stress will cause the substrate to form a concave surface, and the compressive stress will cause the substrate to form a convex surface. * When the film stress is too large, the Exfoliation or formation of excessive voids and cracks is not conducive to the maximum film thickness, layer stacking structure, film quality characteristics of optical films and semiconductor films. Therefore, in the thin film plating industry, film stress is an important factor considered in the manufacturing process. Relatively, The measurement method that determines the magnitude of the film stress is also very important. Since the thin film stress will bend the deposited substrate, if the degree of bending of the substrate can be measured after the thin film is attached to the substrate, the magnitude of the thin film stress can be obtained. At present, most of the methods for measuring the stress of a thin film use the above-mentioned physical principles, and the biggest difference lies in the method used to determine the amount of bending of the substrate after the film is attached. For example, using a microscope to observe the amount of bending or observing the interference fringe. The number difference represents the variation of the interference fringe to calculate the amount of bending of the substrate after the film is attached. However, the degree of substrate bending determined by these methods is less accurate, because a larger scale must be used to match the amount of artificial judgment. Measure the amount of bending. Another method is to guide the laser light to hit the substrate, and measure the curvature radius of the substrate to estimate the curvature of the substrate. However, it is necessary to calculate the bending amount of the substrate little by little to obtain the bending amount of the entire surface of the substrate. Slower. Due to the miniaturization trend of 1C, the thickness of the thin film deposited on the substrate is getting thinner and thinner to the micron level. Under this trend, the national standard rate (C: NS) A4 specification (210X297 mm) of this paper scale caused by thin film deposition in this state V. Description of the invention (6) (Amended in September 1999); W years, add 丨 Φ = tan '(please read the note on the back page first) 2 (12 ~ h) 2 / 3- / 5-Λ where Φ is the phase function of this point, ^ to ^ represent five The digitized intensity of the point in the interferogram, and the obtained phase function can represent the profile of the measured surface. Because the thin film has stress, it will bend the substrate when deposited on the substrate. Assuming that the film stress is isotropic, the difference between the amount of bending (relative height) of the substrate before and after deposition can be measured and substituted into the following formula Calculating Membrane Stress
Es ·ά) ·Δ^ σ = -^~~1- 3r2(\-vs)df 其中爲膜應力，△(?爲沈積前後由基板中心點至半徑L處 相對高度的差値，r爲基板上量測位置的半徑値，ds爲基板 厚度，df爲膜厚，而E,和t分別爲楊氏係數和帕松比 (PoissoiL, s-talioj。若〇爲正値表示伸張應力，若〇·爲負値 表壓縮應力。換言之，沈積後基板彎曲量向下爲伸張應力， 而向上彎曲爲壓縮應力。 經濟部智慧財產局員工消費合作社印製 最後相移干涉圖之分析動作則利用儲存於該PC由發明 人自行發展的軟體來處理，其功能包括擷取五張千涉圖（間 隔π/2相位），干涉圖數位化處理，利用Hariharan相位還 原法產生相位圖（phase map)，由相位圖所表示的波數計算 彎曲量與平均應力。 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） A7 B7 五、發明説明（2 ) 基板彎曲量將大幅地降低，而更不易以目前已知的方法來 量測薄膜應力。 發明要旨 本發明量測薄膜應力大小的方法，也是靠計算基板因 薄膜附著後的彎曲程度，但是其中選用厚度小於1.8mm的基 板並使用光的干涉原理和數位相移技術，來決定基板因薄 膜附著後的彎曲程度。由於此方法僅量測一次就可計算出 因薄膜附著基板後的彎曲量，爲一快速簡單的方法，且使 用數位相移技術來分析干涉圖，因此即使干涉圖的干涉條 紋無明顯變化，也能計算干涉相位大小，準確地提供基板 的彎曲量，於是可有效改善及解決上述先前技藝中各項方 法的缺點。 本發明所揭示之一種藉干涉相移方式來量測沈積於一 基板上的薄膜的應力之方法，包含下列步驟： a) 選取一厚度小於或等於1.8mm的基板； b) 量測該基板的一待測面上的相位函數； c) 於該基板的待測面沈積一薄膜； d) 除了以步驟c)沈積後基板取代沈積前的基板，以相同 於步驟b)的條件量測沈積後基板的相位函數； e) 利用步騾b)及d)所量測的相位函數求出相對於該基 板上的一中心點，沈積前與沈積後基板上的相同位 置的點的相對高度及其差値； 0利用步驟e)的相對高度的差値算出複數個相同位置 本紙认尺度述州肀闽國家掠牟（CNS ) Λ4规格（210X297公釐） A7 B7 五、發明說明（7 ) 實施例 修正& 丨铺-本豺年？月、 丨補; ί__ (1999年9月修正） (請先閱讀背面之注意事項再填寫本頁) 本實施例利用圖一所示的薄膜應力量測系統分別對沈 積前及Nb205薄膜沈積後的基板產生五張等相位偏移量的 干涉圖形，以影像擷取器90捕捉此五張干涉圖並予以數位 化*計算相位，獲得基板彎曲量與薄膜應力。Nb2〇i薄膜的 厚度爲〇·274μιη，基板的厚度爲1.5mm，材質爲BK7，等相 位偏移量的動作是利用該個人電腦（PC)中的程式控制該 PZT控制元件100(在此爲一直流電源供應器），提供定量電 壓驅動壓電陶瓷元件（PZT)，使得PZT元件產生79nm的移動 量且使干涉條紋位移1/4條紋間距，可取得定量相位差τ /2 偏移量的五張干涉圖。Nb205薄膜沈積前和沈積後相位偏移 量〇度和180度的干涉圖被分別示於圖二（a)〜(d)。其次， Nb205薄膜沈積前和沈積後的相位圖被示於圖三（a)及三 (b)，於圖三（a)中200個灰階代表3個波長，而於圖三（b)中200 個灰階代表2個波長。最後以Zernike多項式做波前擬合並消 除傾斜量，則鍍膜前後基板表面之波前輪廓圖如圖四（a)和 (b)所示，再將此二者的波前相減即得膜面的變形量，如圖 四（c)，依此方法測得Nb205薄膜的平均應力爲-〇.33GPa。 經濟部智慧財產局員工消費合作社印製 圖示之簡單說明 圖一顯示一適用於本發明方法的薄膜應力量測系統的 示意圖，其中利用一相移式Twyman-Green干涉儀。 圖二爲於本發明實施例中Nb205薄膜沈積前和沈積後 相位偏移量〇度和180度的干涉圖，其中（a)沈積前相位偏移 -10- 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） A7 B7 五、發明説明（3 ) 的點的膜應力，並算出膜應力平均値； 其中步驟的b)的相位函數係依下列步驟量測： i)將由同一光源產生的兩道光束分別照在一參考板及 該基板的待測面，而產生兩道反射光束； Π)使該兩道反射光束合併成一單一光束並於一屛幕上 形成一干涉圖； iii) 數位化該干涉圖的光強度並記錄之； iv) 將該參考板或基板沿垂直於光束的方向等位移動數 個位置，並依i)至iii)的步驟分別記錄該等數個位置 的干涉圖的數位化光強度； v) 使用步驟iii)及iv)獲得的數位化光強度計算出該基 板的待測面的相位函數。 較佳的，該步驟iv)的等位移動係藉由在該參考板背對 光束的一面上設置一壓電陶瓷（PZT)元件，及一與其連接的 直流電源供應器來進行，其中該直流電源供應器受一電腦 控制而輸出一預定電壓至該PZT元件。 較佳的，於步驟iii)中以一電荷耦合元件（CCD)攝影機 攝取該干涉圖，並數位化所攝取干涉圖像的每一像素點的 光強度。較佳的，該CCD攝影機所輸出的數位化光強度被 輸入該電腦並記錄於其中，並藉由該電腦所儲存的程式於 該電腦中算出該相位函數及該等複數個相同位置的點的相 對高度、相對高度的差値、膜應力、及膜應力的平均値。 較佳的，於步驟iv)中該參考板被以八分之一波長等位 移動四個位置•於是連同步驟iii)共獲得相位偏移0度、90Es · ά) · Δ ^ σ =-^ ~~ 1- 3r2 (\-vs) df where is the film stress, △ (? Is the relative height difference from the center point of the substrate to the radius L before and after deposition, r is the substrate The radius 値 at the measurement position above, ds is the thickness of the substrate, df is the thickness of the film, and E, and t are the Young's coefficient and Passon's ratio (PoissoiL, s-talioj. If 〇 is positive, 値 means the tensile stress, if 〇 · It is negative compressive stress. In other words, after the deposition, the bending amount of the substrate downwards is the tensile stress, and the upward bending is the compressive stress. The analysis action of the final phase shift interference diagram printed by the Employees ’Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs is stored in The PC is processed by software developed by the inventor. Its functions include capturing five interferograms (interval π / 2 phase), digitizing the interference pattern, and generating a phase map using Hariharan's phase reduction method. The wave number indicated by the phase diagram is used to calculate the bending amount and average stress. This paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) A7 B7 V. Description of the invention (2) The bending amount of the substrate will be greatly reduced. And it ’s harder to use the methods that are currently known Measuring the stress of the film. Summary of the invention The method of measuring the stress of the film of the present invention is also based on calculating the degree of bending of the substrate after the film is attached. However, a substrate with a thickness of less than 1.8mm is selected and the principle of light interference and digital phase shift technology are used. Determines the degree of bending of the substrate after the film is attached. Since this method can calculate the amount of bending after the film is attached to the substrate only by measuring once, it is a fast and simple method and uses digital phase shift technology to analyze the interference pattern, so even The interference fringe of the interferogram does not change significantly, and the interference phase can also be calculated to accurately provide the amount of bending of the substrate. Therefore, the shortcomings of the methods in the prior art can be effectively improved and solved. An interference phase shift disclosed by the present invention A method for measuring the stress of a thin film deposited on a substrate in a manner that includes the following steps: a) selecting a substrate having a thickness of 1.8 mm or less; b) measuring a phase function on a substrate to be measured of the substrate; c ) Depositing a thin film on the test surface of the substrate; d) in addition to replacing the substrate before deposition with the substrate after step c), Measure the phase function of the substrate after deposition under the same conditions as in step b); e) Use the phase function measured in steps 骡 b) and d) to find a center point on the substrate before and after deposition The relative heights of the points at the same position on the map and their differences; 0 Use the difference in the relative heights of step e) to calculate a plurality of the same positions. The paper's recognition scale is described by the state and the country (CNS) Λ4 specification (210X297 mm). A7 B7 V. Description of the invention (7) Modification of the embodiment & Month, 丨 supplement; ί__ (Amended in September 1999) (Please read the precautions on the back before filling out this page) This example uses the thin film stress measurement system shown in Figure 1 to measure the pre-sediment and Nb205 thin films respectively. The substrate generates five interference patterns with the same phase shift amount. The five interferograms are captured by the image capture device 90 and digitized * to calculate the phase to obtain the substrate bending amount and film stress. The thickness of the Nb20i film is 0.274 μm, the thickness of the substrate is 1.5 mm, and the material is BK7. The action of the phase offset is to use a program in the personal computer (PC) to control the PZT control element 100 (here: A DC power supply), which provides a quantitative voltage to drive the piezoelectric ceramic element (PZT), so that the PZT element generates a movement of 79 nm and shifts the interference fringe by 1/4 fringe pitch to obtain a quantitative phase difference τ / 2 offset. Five interference maps. The interferograms of the phase shifts of 0 ° and 180 ° before and after deposition of Nb205 thin films are shown in Figures 2 (a) ~ (d), respectively. Secondly, the phase diagrams of Nb205 thin film before and after deposition are shown in Figures 3 (a) and 3 (b). In Figure 3 (a), 200 gray levels represent 3 wavelengths, and in Figure 3 (b). 200 gray levels represent 2 wavelengths. Finally, use Zernike polynomial to do wavefront fitting and eliminate the amount of inclination. The wavefront profiles of the substrate surface before and after coating are shown in Figures 4 (a) and (b). Subtract the wavefronts of the two to obtain the film. The amount of surface deformation is shown in Figure 4 (c). According to this method, the average stress of the Nb205 film is -0.33GPa. Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economics Brief description of the diagram Figure 1 shows a schematic diagram of a thin film stress measurement system suitable for the method of the present invention, in which a phase-shifting Twyman-Green interferometer is used. FIG. 2 is an interference diagram of phase shifts of 0 degrees and 180 degrees before and after deposition of Nb205 thin film in an embodiment of the present invention, where (a) phase shift before deposition -10- This paper scale is applicable to Chinese National Standard (CNS ) A4 specification (210 X 297 mm) A7 B7 5. The film stress at the point of the invention description (3) and calculate the average film stress 値; where the phase function of step b) is measured according to the following steps: i) will be measured by Two light beams generated by the same light source are respectively irradiated on a reference plate and the test surface of the substrate to generate two reflected light beams; Π) combining the two reflected light beams into a single light beam and forming an interference pattern on a curtain ; Iii) digitize the light intensity of the interferogram and record it; iv) move the reference plate or substrate equally by several positions in the direction perpendicular to the beam, and record the numbers separately according to steps i) to iii) Digitized light intensity of the interferogram at each position; v) Calculate the phase function of the test surface of the substrate using the digitized light intensity obtained in steps iii) and iv). Preferably, the isoposition movement of step iv) is performed by setting a piezoelectric ceramic (PZT) element on a side of the reference plate facing away from the light beam, and a DC power supply connected thereto, wherein the DC The power supply is controlled by a computer and outputs a predetermined voltage to the PZT element. Preferably, in step iii), the interference pattern is captured by a charge coupled device (CCD) camera, and the light intensity of each pixel point of the captured interference image is digitized. Preferably, the digitized light intensity output by the CCD camera is input to the computer and recorded therein, and the phase function and the plurality of points at the same position are calculated in the computer by a program stored in the computer. Relative height, relative height difference, film stress, and average film stress. Preferably, in step iv) the reference plate is shifted equidistantly by one-eighth wavelength by four positions. Then together with step iii) a phase shift of 0 degrees and 90 degrees is obtained.
本紙張尺度適;1]中囤國家標準（CNS ) A4規格（210X 297公釐) I (誚先閱讀背面之注意事項再磧55本頁) L---^------------S--r--.--、1T---------------------- %丨 A7 五、發明說明（4 ) 補充 (1999年9月修正） 度、180度、270度和360度的五個相位偏移的干涉圖的數 位化光強度依下列公式算出該相位函數： 0 = tan' (請先閲讀背面之注意事項ΐ&本頁： 2(/2~/4) 式中I!，12 ’ 13，14及15代表該干涉圖的某一點的數位化光 強度，及 Φ爲該點的相位。 較佳的，該步驟e)的相對高度係依下式算出： 相對高度=·^^(Φ,-Φε) 4/Γ 式中Φ,爲基板上半徑r處一點的相位，及 Φ,爲基板上中心點的相位。 較佳的，該步驟i)的光源爲雷射光或經一狹縫所產生 的狹縫光源。 Φ 發明詳細說明 經濟部智慧財產局員工消費合作社印製 量測沈積後和沈積前基板彎曲量的差異，而獲得薄膜 應力，此爲量測薄膜應力的一種方法，此方法的最大關鍵 在於如何決定沈積後和沈積前基板彎曲量的差異，過去有 使用顯微鏡放大刻度決定彎曲量差異，但放大倍率仍然不 夠，所獲得彎曲量較不準確。也有使用干涉條紋數目的變 化決定彎曲量差異，但因條紋本身有寬度且需人工量測計 算條紋數目變化，較不客觀，也就較不準確。也有導入雷 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） A7 ____________B7__ 五、發明説明（5 ) 射光利用反射方式決定彎曲量差異，但因需逐點量測才能 獲得整面的彎曲量*量測速度緩慢。本發明則結合光學千 涉原理和相移技術決定沈積後和沈積前基板彎曲量的差 異，可改進上述缺點*以下配合圖示進一步說明爲本發明。 首先本發明基板的選擇必須厚度小於或等於1.8mm，然 後本發明建立一套相移式Twyman-Green干涉儀（如圖一）； 由一氮氖雷射1 〇經一顯微物鏡2 1與針孔22所構成的空間濾 波器20而形成一點光源，再經準直透鏡30產生一平面波 前，藉分光鏡40將平面波前振幅分割爲反射波前和透射波 前，然後反射光和透射光經參考面50與待測面60(基板）反射 之後，兩反射光再經分光鏡40重新合併成單一光束成像於 毛玻璃屛幕70上，利用CCD攝影機80及一影像擷取器90將 干涉圖影像顯示在一個人電腦（PC)的監視器上。這種相移 式Twyman-Green干涉儀可以量測鍍膜前和鍍膜後干涉條紋 的相位。相移方式的基本原理是遵循Hariharan演算法，利 用該干涉儀建立一套以個人電腦爲基礎的薄膜應力量測系 統。於干涉儀的參考面處安裝一由該個人電腦控制的壓電 陶瓷元件（PZT)，藉助一 PZT控制元件1 00使該參考面50以等 位移動量（八分之一波長）沿垂直於光束的方向連續移動參 考面至全部有五個位置，就可獲得五張相移干涉圖，而每 —位置的干涉圖都可由影像擷取器90予以數位化。五張數 位化的干涉圖，利用相移技術可獲得待測面的輸廓圖，從 五張干涉圖中每一像素點的數位化強度代入下列公式來計 算干涉條紋的相位 本紙张尺度.¾州t囤國家標準（CNS ) Λ4規格（210X297公瀣） (請先閲讀背面之注意寧項再填寫本頁) 訂 五、發明說明（6 ) (1999年9月修正) ;修正 本W年，甩 丨補充 Φ = tan' (請先閱讀背面之注意事項本頁) 2(12~h) 2/3-/5-Λ 其中Φ爲該點的相位函數，^至^代表五張干涉圖該點的 數位化強度，而求出的相位函數則可代表待測面的輸廓 圖。因爲薄膜有應力，故沈積在基板上會使基板彎曲，假 設薄膜應力爲各向同性（isotropic)，可以藉著薄膜沈積前 和沈積後測量基板彎曲量（相對高度）的差値，代入下列公 式計算膜應力This paper is of suitable size; 1] China National Standard (CNS) A4 specification (210X 297mm) I (诮 Please read the precautions on the back before going to page 55) L --- ^ -------- ---- S--r --.--, 1T ----------------------% 丨 A7 V. Description of the Invention (4) Supplement (1999) (Amended in September) The digitized light intensity of the five-phase-shifted interferograms of degrees, 180 degrees, 270 degrees, and 360 degrees is used to calculate the phase function according to the following formula: 0 = tan '(Please read the precautions on the back ΐ & amp This page: 2 (/ 2 ~ / 4) where I !, 12 '13, 14, and 15 represent the digitized light intensity at a point in the interferogram, and Φ is the phase at that point. Preferably, the The relative height of step e) is calculated according to the following formula: Relative height = · ^^ (Φ, -Φε) 4 / Γ where Φ is the phase of a point at a radius r on the substrate, and Φ is the center point of the substrate on the substrate. Phase. Preferably, the light source in step i) is laser light or a slit light source generated through a slit. Φ The invention explains in detail that the consumer cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs prints and measures the difference in the amount of bending of the substrate after deposition and before deposition, and obtains the film stress. This is a method for measuring film stress. The key to this method is how to determine The difference between the amount of bending of the substrate after deposition and that of the deposition before. In the past, the difference in the amount of bending was determined using a microscope magnification scale, but the magnification was still insufficient, and the obtained amount of bending was less accurate. There are also variations in the amount of interference using the number of interference fringes, but because the fringe itself has a width and requires manual measurement to calculate the number of fringes, it is less objective and less accurate. There are also imported Rabin paper standards that apply the Chinese National Standard (CNS) A4 specifications (210 X 297 mm) A7 ____________B7__ V. Description of the invention (5) The reflected light uses the reflection method to determine the difference in bending amount, but it needs to be measured point by point to get the whole The amount of deflection of the surface * The measurement speed is slow. The present invention combines the optically related principles and phase shifting techniques to determine the difference in the amount of substrate bending after deposition and before deposition, which can improve the above disadvantages. * The following figure is further illustrated as the present invention. First, the substrate of the present invention must be selected to have a thickness less than or equal to 1.8 mm. Then, the present invention establishes a set of phase-shifting Twyman-Green interferometers (as shown in Fig. 1); The spatial filter 20 formed by the pinhole 22 forms a point light source, and then generates a plane wavefront through the collimator lens 30. The plane wavefront amplitude is divided into a reflected wavefront and a transmitted wavefront by a beam splitter 40, and then reflected light and transmitted light After being reflected by the reference surface 50 and the surface to be measured 60 (substrate), the two reflected lights are recombined into a single beam by the beam splitter 40 to be imaged on the frosted glass curtain 70. The interference pattern is captured by a CCD camera 80 and an image capture device 90 The image is displayed on a personal computer (PC) monitor. This phase-shifting Twyman-Green interferometer can measure the phase of interference fringes before and after coating. The basic principle of the phase shift method is to follow the Hariharan algorithm, and use this interferometer to build a personal computer-based thin film stress measurement system. A piezoelectric ceramic element (PZT) controlled by the personal computer is installed at the reference plane of the interferometer, and the reference plane 50 is moved perpendicularly to the reference plane 50 by an equal displacement amount (one-eighth wavelength) by means of a PZT control element 100. The direction of the beam continuously moves the reference plane to all five positions to obtain five phase-shifted interferograms, and the interferograms at each position can be digitized by the image capture device 90. Five digitized interferograms. The phase shift technique can be used to obtain the profile of the measured surface. The digitized intensity of each pixel in the five interferograms is substituted into the following formula to calculate the phase scale of the interference fringe. ¾ State t store national standard (CNS) Λ4 specification (210X297 gong) (Please read the note on the back before filling in this page) Order V. Description of the invention (6) (Amended in September 1999); Amend this year, Add Φ = tan '(please read the note on the back page first) 2 (12 ~ h) 2 / 3- / 5-Λ where Φ is the phase function at this point, and ^ to ^ represent five interferograms. The digitized intensity of the points, and the obtained phase function can represent the profile of the measured surface. Because the thin film has stress, it will bend the substrate when deposited on the substrate. Assuming that the film stress is isotropic, the difference between the amount of bending (relative height) of the substrate before and after deposition can be measured and substituted into the following formula Calculating Membrane Stress
Es ·ά) ·Δ^ σ = -^~~1- 3r2(\-vs)df 其中爲膜應力，△(?爲沈積前後由基板中心點至半徑L處 相對高度的差値，r爲基板上量測位置的半徑値，ds爲基板 厚度，df爲膜厚，而E,和t分別爲楊氏係數和帕松比 (PoissoiL, s-talioj。若〇爲正値表示伸張應力，若〇·爲負値 表壓縮應力。換言之，沈積後基板彎曲量向下爲伸張應力， 而向上彎曲爲壓縮應力。 經濟部智慧財產局員工消費合作社印製 最後相移干涉圖之分析動作則利用儲存於該PC由發明 人自行發展的軟體來處理，其功能包括擷取五張千涉圖（間 隔π/2相位），干涉圖數位化處理，利用Hariharan相位還 原法產生相位圖（phase map)，由相位圖所表示的波數計算 彎曲量與平均應力。 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） A7 B7 五、發明說明（7 ) 實施例 修正& 丨铺-本豺年？月、 丨補; ί__ (1999年9月修正） (請先閱讀背面之注意事項再填寫本頁) 本實施例利用圖一所示的薄膜應力量測系統分別對沈 積前及Nb205薄膜沈積後的基板產生五張等相位偏移量的 干涉圖形，以影像擷取器90捕捉此五張干涉圖並予以數位 化*計算相位，獲得基板彎曲量與薄膜應力。Nb2〇i薄膜的 厚度爲〇·274μιη，基板的厚度爲1.5mm，材質爲BK7，等相 位偏移量的動作是利用該個人電腦（PC)中的程式控制該 PZT控制元件100(在此爲一直流電源供應器），提供定量電 壓驅動壓電陶瓷元件（PZT)，使得PZT元件產生79nm的移動 量且使干涉條紋位移1/4條紋間距，可取得定量相位差τ /2 偏移量的五張干涉圖。Nb205薄膜沈積前和沈積後相位偏移 量〇度和180度的干涉圖被分別示於圖二（a)〜(d)。其次， Nb205薄膜沈積前和沈積後的相位圖被示於圖三（a)及三 (b)，於圖三（a)中200個灰階代表3個波長，而於圖三（b)中200 個灰階代表2個波長。最後以Zernike多項式做波前擬合並消 除傾斜量，則鍍膜前後基板表面之波前輪廓圖如圖四（a)和 (b)所示，再將此二者的波前相減即得膜面的變形量，如圖 四（c)，依此方法測得Nb205薄膜的平均應力爲-〇.33GPa。 經濟部智慧財產局員工消費合作社印製 圖示之簡單說明 圖一顯示一適用於本發明方法的薄膜應力量測系統的 示意圖，其中利用一相移式Twyman-Green干涉儀。 圖二爲於本發明實施例中Nb205薄膜沈積前和沈積後 相位偏移量〇度和180度的干涉圖，其中（a)沈積前相位偏移 -10- 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） A7 B7 五、發明説明（8 ) 量0度；（b)沈積前相位偏移量180度；（c)沈積後相位偏移量 〇度；及（d)沈積後相位偏移量1 80度的干涉圖。 圖三（a)及三（b)分別爲於本發明實施例中所獲得的 Nb205薄膜沈積前和沈積後的柑位圖，於圖三（a)中200個灰 階代表3個波長1而於圖三（b)中200個灰階代表2個波長》 圖四（a)和四（b)分別爲於本發明實施例中所獲得的 Nb205薄膜沈積前和沈積後的基板表面之輪廓圖，而圖四（c) 爲圖四（b)沈積後的基板表面輪廓圖減去圖四（a)沈積前的 基板表面輪廓圖所得的膜面變形量。 圖號說明 10...氮氖雷射 21…顯微物鏡 22…針孔 2〇…空間濾波器 30…準直透鏡 40...分光鏡 50…參考面 60...待測面（基板）70…毛玻璃屛幕 80...CCD攝影機 90…影像擷取器 100...PZT控制元件 本紙张尺度適扪十國國家標丰（CNS ) A4规格（210X297公釐） 1 11Es · ά) · Δ ^ σ =-^ ~~ 1- 3r2 (\-vs) df where is the film stress, △ (? Is the relative height difference from the center point of the substrate to the radius L before and after deposition, r is the substrate The radius 値 at the measurement position above, ds is the thickness of the substrate, df is the thickness of the film, and E, and t are the Young's coefficient and Passon's ratio (PoissoiL, s-talioj. If 〇 is positive, 値 means the tensile stress, if 〇 · It is negative compressive stress. In other words, after the deposition, the bending amount of the substrate downwards is the tensile stress, and the upward bending is the compressive stress. The analysis action of the final phase shift interference diagram printed by the Employees ’Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs is stored in The PC is processed by software developed by the inventor. Its functions include capturing five interferograms (interval π / 2 phase), digitizing the interference pattern, and generating a phase map using Hariharan's phase reduction method. The wave number indicated by the phase diagram is used to calculate the bending amount and average stress. This paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) A7 B7 V. Description of the invention (7) Modification of the embodiment & This leap year? Month, 丨 supplement; ί__ (revised in September 1999 ) (Please read the precautions on the back before filling out this page) This example uses the thin film stress measurement system shown in Figure 1 to generate five interference patterns with equal phase shifts on the substrate before deposition and after Nb205 thin film deposition. The image capture device 90 was used to capture the five interferograms and digitize them * to calculate the phase to obtain the substrate bending amount and film stress. The thickness of the Nb20i film was 0.274 μm, the thickness of the substrate was 1.5mm, and the material was BK7 The action of isophase shift is to use a program in the personal computer (PC) to control the PZT control element 100 (in this case, a DC power supply), to provide a quantitative voltage to drive the piezoelectric ceramic element (PZT), so that the PZT The element generates a shift of 79nm and shifts the interference fringe by 1/4 fringe pitch to obtain five interferograms with a quantitative phase difference τ / 2 offset. The phase offsets of the Nb205 film before and after deposition are 0 degrees and 180 degrees. The interferograms are shown in Figures 2 (a) ~ (d). Secondly, the phase diagrams of Nb205 thin film before deposition and after deposition are shown in Figures 3 (a) and 3 (b), as shown in Figure 3 (a). 200 gray levels represent 3 wavelengths, and The 200 gray scales in three (b) represent 2 wavelengths. Finally, Zernike polynomials are used to fit the wavefront and eliminate the amount of tilt. The wavefront profiles of the substrate surface before and after coating are shown in Figures 4 (a) and (b). Then, subtract the wavefronts of the two to obtain the deformation of the film surface, as shown in Figure 4 (c). According to this method, the average stress of the Nb205 film is -0.33GPa. Employees' Cooperatives, Intellectual Property Bureau, Ministry of Economic Affairs Brief description of printed diagrams Figure 1 shows a schematic diagram of a thin film stress measurement system suitable for the method of the present invention, in which a phase-shifting Twyman-Green interferometer is used. FIG. 2 is an interference diagram of phase shifts of 0 degrees and 180 degrees before and after deposition of Nb205 thin film in an embodiment of the present invention, where (a) phase shift before deposition -10- This paper scale is applicable to Chinese National Standard (CNS ) A4 specification (210 X 297 mm) A7 B7 V. Description of the invention (8) The amount is 0 degrees; (b) The phase offset before deposition is 180 degrees; (c) The phase offset after deposition is 0 degrees; and (d) ) Interferogram with a phase offset of 180 degrees after deposition. Figures 3 (a) and 3 (b) are citrus bit maps of the Nb205 thin film obtained before and after deposition in the examples of the present invention. In FIG. 3 (a), 200 gray levels represent 3 wavelengths1 and In Figure 3 (b), 200 gray levels represent 2 wavelengths. "Figures 4 (a) and 4 (b) are the contours of the substrate surface before and after deposition of the Nb205 film obtained in the embodiment of the present invention, respectively. Figure 4 (c) is the substrate surface profile after the deposition of Figure 4 (b) minus the substrate surface profile before the deposition of Figure 4 (a). Description of the drawing number 10 ... Neon laser 21 ... Microscope objective 22 ... Pinhole 20 ... Spatial filter 30 ... Collimating lens 40 ... Beamsplitter 50 ... Reference surface 60 ... Plane to be measured (substrate ) 70 ... Frosted glass screen 80 ... CCD camera 90 ... Image capture device 100 ... PZT control element The paper size is suitable for the national standard of ten countries (CNS) A4 specification (210X297 mm) 1 11