A7 B7 4 4 Ο 3 t w f. d o c / Ο Ο 8 五、發明说明U ) 本發明是有關於一種化學機械硏磨終點監測方法及g 置’且特別是有關於一種利用監測硏磨液之阻抗來作爲研： 磨終點指標的方法及裝置。 在現今半導體製程中，由於積集度提高，精度要求也 愈來愈高，然而在微影製程中如何使晶圓表面平坦化，是 確保微影精度的重要關鍵之一。化學機械硏磨法（Chemicai Mechanical Polishing, CMP)乃現今半導體製程中，常來作 爲晶圓平坦化的方法，化學機械硏磨法可獲得良好的全面 性表面平坦化（global surface uniformity)。然而，影響化學 機械硏磨法的平坦度之眾多因素中，硏磨終點的偵測即是 重要關鍵之一。 目前化學機械硏磨已廣泛應用於金屬層（比如鎢、銅）， 以及介電層（比如氧化矽）之硏磨或平坦化，更是金屬鑲嵌、 淺溝渠隔離製程中所經常使用的方法。請參照第1圖，其 所繪示爲習知化學機械硏磨後晶片之剖面示意圖。以淺溝 渠隔離製程爲例，在矽基底10經過定義形成多個溝渠 12a、12b後，塡入介電材質14 ’比如氧化砂，然後進行 化學機械硏磨。當然’溝渠12a、12b因應電路佈置之需 要，在基底10上的分布不一定十分均勻，必然有較寬廣 之溝渠12a以及較狹窄之溝渠12b。對於化學機械硏磨製 程本身特性來說，對於溝渠分布較寬廣區域的硏磨速率， 與溝渠分布較緊密區域的硏磨速率是不相同的，而爲了確 保不會產生殘留於基底10表面’適當的過度硏磨（over polishing)是需要的。由於目前無法精確偵測硏磨終點（end 本紙張尺度適州中國國家栋隼（CNS ) A4規格（210X 297公釐） (誚先閲讀背面之注意事項再"荇本頁)A7 B7 4 4 Ο 3 tw f. Doc / Ο Ο 8 V. Description of the invention U) The present invention relates to a method and method for monitoring end points of chemical mechanical honing, and in particular to a method for monitoring impedance using a honing fluid As a research: Method and device for grinding endpoint indicators. In today's semiconductor processes, due to the increase in the degree of accumulation, the accuracy requirements are getting higher and higher. However, how to flatten the wafer surface in the lithography process is one of the important keys to ensure the accuracy of lithography. Chemical mechanical honing method (Chemicai Mechanical Polishing, CMP) is currently used as a method for wafer planarization in semiconductor processes. The chemical mechanical honing method can obtain good global surface uniformity. However, among the many factors that affect the flatness of the chemical mechanical honing method, the detection of the honing end point is one of the important keys. At present, chemical mechanical honing has been widely used in the honing or planarization of metal layers (such as tungsten and copper) and dielectric layers (such as silicon oxide), and it is a method often used in metal inlaying and shallow trench isolation processes. Please refer to FIG. 1, which is a schematic cross-sectional view of a wafer after conventional chemical mechanical honing. Taking the shallow trench isolation process as an example, after the silicon substrate 10 is defined to form a plurality of trenches 12a, 12b, a dielectric material 14 'such as oxidized sand is impregnated, and then subjected to chemical mechanical honing. Of course, the ditch 12a, 12b is not necessarily uniformly distributed on the substrate 10 due to the needs of the circuit arrangement. There must be a wider trench 12a and a narrower trench 12b. For the characteristics of the chemical mechanical honing process itself, the honing rate for the wide area of the trench is not the same as the honing rate of the area with the tightly distributed trench, and in order to ensure that it does not remain on the surface of the substrate 10, it is appropriate. Over polishing is needed. As it is currently impossible to accurately detect the honing end point (end of this paper, China National Building Standard (CNS) A4 size (210X 297 mm)) (诮 Please read the precautions on the back before quoting this page)
、1T 部 屮 ：k iT •!v. r.j i! ih f /.、 <1 印 V- ^"部屮，Λ:(^β 而，•^J^f'u.^'y „03 —-/〇〇S ^ — - - — _._ Ο / 一.-- --------— ____ 7、發明说明（：） ~ point) ’造成過度硏磨決定困難’然而不當之過度硏磨會 在寬廣之溝渠12a形成凹陷現象(dishing，如圖中μ所示^ 在緊密排列之溝渠Ub附近則形成侵触現象(⑽si〇n，如 圖中18所利。不管凹陷現象或侵軸現象，不僅會影響基 底10表面之平坦化，還會造成後續製程許多不利影響， 比如頸結效應（Kink Effect)，甚至在積集度較高的元件， 還會造成金屬內連線間的介電物質不足，而影響元件操作 等° 習知監測化學機械硏磨法之硏磨終點的方法可分爲三 鎮：（1)以硏磨墊之溫度來作監測標準；⑺以硏磨表面之 摩擦係數2爲^測標準；（3)以硏磨表面之反射率作爲監測 檫準。就第一種方法而言，由於金屬層與介電層相對於硏 磨g之摩，係數並不相同，因此硏磨時產生之熱能亦不相 同，所以b成硏磨金屬層時與硏磨介電層時硏磨墊的溫度 會有褰異。利用偵測硏磨墊溫度即可了解硏磨程度，而一 般是利用紅外線感測器（Infrared sensor)來監測硏磨墊溫 度。第二種方法亦是利用金屬層與介電層相對於硏磨墊之 摩擦係數不相同，來作爲硏磨程度之指標。一般可藉由量 測硏磨墊座(table of P〇lishing pad)之驅動馬達的電流，或 晶圓承載座(wafer carrier)之驅動馬達的電流來監測摩擦係 數，作爲硏磨程度的指標。 經由實驗了解，利用硏磨墊之紅外線訊號作爲監測源， 需在硏磨墊轉速較高且硏紫流速（slurry flow rate)較低時， 才具有較好之靈敏度。而利用量測硏磨墊座之驅動馬達的 4 尺度川中國國家標率（CNS ) A4規格（210X297公楚） (誚九閱讀背而之注意事項再填寫本頁) % 訂 A7 B7 44〇3i\v r.doc/008 五、發明説明（\ ) 笔k作爲監測訊號源’其監測靈敏度與硏磨時的下壓力 (down force)有很大關係。至於以晶圓承載座之驅動馬達 的電流作爲監測訊號源’則需要在硏磨墊轉速較低且晶圓 承載座之轉速較高的情況下，才具有較高之靈敏度。 至於習知第三種監測方式，係利用被硏磨薄膜與下層 之薄膜反射率不同’（比如硏磨鎢，其下層爲介電層），藉 由掃描晶圓表面反射光譜作爲化學機械硏磨之硏磨終點監 測之判斷基準’一般有兩種模式： 1. 利用反射光譜中在一固定波長之位置的曲線斜率， 相對於時間參數的特性曲線，作爲監測指標。然而，此種 監測方式’會因所選取之固定波長不同而受影響，而且晶 圓與晶圓間的重複性（repeatability)，亦會嚴重影響此種監 測方式的可靠度。 2. 利用各時段之反射率作爲監測指標，比如計算各時 段各波長之平均反射率總和，其相對於時間參數亦可獲得 一特性曲線。然而由實驗得知靠近硏磨終點段之特性曲線 的曲率値並不大，表示其變化較爲平緩，不易找到一個明 顯之硏磨終點參考値。而且，此種監測方式受外界之光源 干擾(noise)很嚴重，因此可靠度亦不佳。 因此本發明就是在提供一種化學機械硏磨的硏磨終點 監測方法，係利用硏磨時所產生之反應物，造成硏磨液之 阻抗變化的特性，即時監測硏磨液之電性，以判斷硏磨終 點。 根據本發明所提出之硏磨終點監測方法，發明亦提供 本紙张尺度適州中國國家標率（CNS ) Α4規格（210X297公釐） (誚先閱讀背面之注意事項"功{^本頁) 、取' ,-β 部 屮 il ii .1 消 t 合 i\ 印 A7 B7 44〇3iwr.d〇c/Q()j. 五'發明説明（C) 一種硏磨終點監測裝置，在化學機械硏磨機台，配置二電 極’其相距一段適當距離，而座落位置在硏磨機台上硏磨 後之硏磨液所必經之處，以監測硏磨後之硏磨液之阻抗。 藉由本發明之硏磨終點監測方法及裝置，可即時監控 硏磨液之阻抗，並依此判斷硏磨狀態，決定硏磨終點，更 可有效控制過度硏磨程度，避免凹陷或侵蝕現象發生。 爲讓本發明之上述和其他目的、特徵、和優點能更明 顯易懂’下文特舉一較佳實施例，並配合所附圖式，作詳 細說明如下： 圖式之簡單說明： 第1圖所繪示爲習知化學機械硏磨後晶片之剖面示意 圖。 第2A、2B圖所繪示爲依照本發明一較佳實施例的一 種雙金屬鑲嵌的製程剖面示意圖。 第3圖所繪不爲依照本發明之化學機械硏磨法件終點 監測裝置之結構示意圖。 第4圖所繪示爲相對於第3圖中6〇所示方向，護環之 仰視圖。 圖式之標示說明： 10矽基底 12a、12b 溝渠 14介電材質 16凹陷 18侵倉虫 本紙張尺ϋ用中园國家標率（CNS ) Α4規格（210^^7 (誚先閱讀背面之注意事項再楨寫本頁) -i衣 、1T. 屮 k -T 消 A ii 印 A7、 1T Department: k iT •! Vrj i! Ih f /., ≪ 1 Print V- ^ " 部 屮, Λ: (^ β And, • ^ J ^ f'u. ^ 'Y „03 — -/ 〇〇S ^ —--— _._ Ο / 一 .-- --------— ____ 7. Description of the invention (:) ~ point) 'It is difficult to make excessive honing decisions' but it is inappropriate Excessive honing will form a depression in the wide ditch 12a (dishing, as shown in μ in the figure) ^ An intrusion phenomenon is formed near the closely arranged ditch Ub (⑽si ON, as shown in FIG. 18. Regardless of the depression phenomenon or invasion The axial phenomenon will not only affect the flatness of the surface of the substrate 10, but also cause many adverse effects in subsequent processes, such as the neck effect (Kink Effect), and even the components with a higher degree of accumulation, will also cause the Insufficient dielectric substances affect the operation of components, etc. The method of monitoring the honing end point of the chemical mechanical honing method can be divided into three towns: (1) the temperature of the honing pad is used as the monitoring standard; the honing surface is used The friction coefficient 2 is the measurement standard; (3) The reflectance of the honing surface is used as the monitoring criterion. As for the first method, since the metal layer is opposite to the dielectric layer The coefficient of honing g is different, so the heat energy generated during honing is also different, so the temperature of the honing pad will be different when honing the metal layer and the dielectric layer when honing. Use detection The temperature of the honing pad can be used to understand the degree of honing. Generally, an infrared sensor is used to monitor the temperature of the honing pad. The second method is also to use the friction between the metal layer and the dielectric layer relative to the honing pad. The coefficients are not the same, as an indicator of the degree of honing. Generally, the current of the driving motor of the table of polishing pad or the current of the driving motor of the wafer carrier can be measured. The friction coefficient is monitored as an indicator of the degree of honing. It is understood through experiments that the infrared signal of the honing pad is used as a monitoring source. It is only required when the honing pad rotates at a high speed and the slurry flow rate is low. Good sensitivity. And the 4 scale Sichuan China National Standard (CNS) A4 specification (210X297) is used to measure the drive motor of the honing pad. A7 B7 44〇3i \ v r. doc / 008 V. Description of the invention (\) Pen k is used as a monitoring signal source. Its monitoring sensitivity has a great relationship with the down force during honing. As for the monitoring signal of the drive motor of the wafer carrier, The source needs to have a higher sensitivity only when the honing pad rotates at a low speed and the wafer carrier rotates at a high speed. As for the conventional third monitoring method, the honing film and the underlying film are used. Different reflectances (such as honing tungsten, whose underlying layer is a dielectric layer). Scanning the wafer surface reflection spectrum as a criterion for the monitoring of honing endpoints for chemical mechanical honing generally has two modes: 1. Using reflection The slope of the curve at a fixed wavelength position in the spectrum is compared to the characteristic curve of the time parameter as a monitoring index. However, this type of monitoring method will be affected by the different fixed wavelengths selected, and the repeatability between wafer and wafer will also seriously affect the reliability of this type of monitoring method. 2. Use the reflectance of each time period as a monitoring index, for example, calculate the sum of the average reflectance of each wavelength at each time period, and obtain a characteristic curve with respect to the time parameter. However, it is known from the experiment that the curvature 特性 of the characteristic curve near the end of the honing is not large, which means that the change is relatively gentle, and it is not easy to find a clear reference to the end of the honing. Moreover, this monitoring method is severely affected by external light sources, so its reliability is also poor. Therefore, the present invention is to provide a honing end point monitoring method for chemical mechanical honing, which uses the characteristics of the resistance change of the honing fluid caused by the reactants generated during honing, and monitors the electric property of the honing fluid in real time to determine Honing the end. According to the honing end point monitoring method proposed by the present invention, the invention also provides the paper size of the Chinese standard (CNS) A4 size (210X297 mm) of the paper size (read the precautions on the back first " function {^ this page) Take the ', -β part 屮 il ii .1 elimination t combination i \ India A7 B7 44〇3iwr.d〇c / Q () j. V. Description of the invention (C) A honing end point monitoring device in chemical machinery The honing machine table is equipped with two electrodes, which are at a proper distance from each other, and is located on the honing machine table where the honing fluid must pass to monitor the resistance of the honing fluid. With the honing end point monitoring method and device of the present invention, the resistance of the honing fluid can be monitored in real time, and the honing state can be judged according to this, and the honing end point can be determined. The degree of over honing can be more effectively controlled to avoid the occurrence of depression or erosion. In order to make the above and other objects, features, and advantages of the present invention more comprehensible, a preferred embodiment is exemplified below, and in conjunction with the accompanying drawings, the detailed description is as follows: Brief description of the drawings: FIG. 1 The drawing is a schematic cross-sectional view of a wafer after conventional chemical mechanical honing. Figures 2A and 2B are schematic cross-sectional views of a bimetal damascene process according to a preferred embodiment of the present invention. FIG. 3 is not a schematic structural diagram of an end-point monitoring device for a chemical mechanical honing method according to the present invention. Figure 4 shows the bottom view of the retaining ring with respect to the direction shown in Figure 3 of Figure 3. Description of the drawings: 10 silicon substrates 12a, 12b trenches 14 dielectric materials 16 depressions 18 invasion of worms This paper ruler uses China National Standards (CNS) Α4 specifications (210 ^^ 7 (read the note on the back first) Matters are reproduced on this page) -i clothing, 1T. 屮 k -T eliminate A ii print A7
4 4 Ο 3 t u f. d c / 0 0 S 五、發明説明（（；） 20基底 22金屬層 24介電層 26a、26b、28 開口 30金屬層 32a、32b金屬插塞 40硏磨台 42硏磨墊 44、54旋轉方向 46晶片夾持器 48晶片 50硏磨液供應裝置 52硏磨液 56護環 58硏磨液收集裝置 60仰視方向 62a、62b硏磨終點監測裝置 64溝槽 66a、66b 電極 68阻抗量測裝置 實施例 本實施例中係以雙金屬鑲嵌（Dual Damascene)製程中所 採用之化學機械硏磨爲例。請參照第2A、2B圖，其繪示 本紙張尺度適州中囤國家標準（CNS ) Λ4規格（210Χ 297公釐） ("先閱讀背面之注意事項再功寫本頁) .4 4 Ο 3 tu f. Dc / 0 0 S V. Description of the invention ((;) 20 substrate 22 metal layer 24 dielectric layer 26a, 26b, 28 opening 30 metal layer 32a, 32b metal plug 40 honing table 42 硏Grinding pads 44, 54 rotation directions 46 wafer holders 48 wafers 50 honing liquid supply device 52 honing liquid 56 guard ring 58 honing liquid collection device 60 bottom direction 62a, 62b honing end point monitoring device 64 groove 66a, 66b Electrode 68 impedance measurement device embodiment In this embodiment, the chemical mechanical honing used in the process of dual metal inlay (Dual Damascene) is taken as an example. Please refer to Figs. 2A and 2B, which show the paper size in Shizhou. Store national standard (CNS) Λ4 specification (210 × 297 mm) (" Read the precautions on the back before writing this page).
、1T 4403t\v i .d〇c/0()S A 7 五、發明説明（t ) _ --- =照本發明-=較佳軸_ —種雙金顯嵌的製程剖面示 。、圖又金屬齡A的技術在高積集度的半導體製程中是經 常應用的技術。基底20上至少有—金屬層a，比如是錦， 金屬層22上沉積介電層24，比如是氧化層。測用二次 微影飽刻製程，形成開口 26a、施及28，其中開口施 作爲連接金屬層22的介層窗㈣，酬口灿及28則是 作爲將^塡^導電材料作爲金屬內連線（interc〇nnecti〇n)之 用。接者，汍積金屬層3〇，比如是銅，以塡滿開口 26a、 j6b、28，並進行化學機械硏磨製程，硏磨金屬層3〇在介 電層24上方的部分，此時利用介電層μ作爲硏磨終止層。 經過硏磨完成後’在開口 26a、26b中即形成金屬插塞32a ; 而在開口 28中形成金屬插塞32b。 一般硏磨液（Slurry)通常包括二種組成：一爲化學活性 組成（Chemically Active Component)包括酸或驗水溶液； 氧化劑’如氰化鐵的(〇^)及錯合劑（(：0卿1以1^1^邮）， 如熱、THF、DMSO寺。另一·爲機械活性組成（Mechanically Active Component)比如二氧化矽微粒、氧化鋁微粒，碳 化矽微粒等之硏磨劑（Abrasive)。在硏磨過程中，金屬 層會與硏磨液中的酸鹼或者氧化劑發生反應而溶解於硏磨 液中，比如銅會氧化成銅氧化物離子或亞銅離子而溶解於 硏磨液中，而鎢會氧化成鎢氧化物離子而溶解於硏磨液 中。吾人發現由於硏磨過程中，硏磨液對於不同材質之薄 膜層，會產生不同的副產品（By-product)，如上述之銅氧 化物離子，鎢氧化物離子，而這些副產品分別具有其導電 8 本纸张尺度诚/1]中國國家榡準（CNS ) Α4規格（210X297公釐） ---------各-- (誚先閱讀背面之注意事項再填寫本S ) 訂 4403i\v)'.doc/008 五、發明说明〇 ) 性，因而溶於硏磨液中會改變硏磨液之阻抗値。因此，硏 磨後之硏磨液的阻抗値實可作爲硏磨終點的指標。 以上述雙金屬鑲嵌中的化學機械硏磨爲例，在硏磨初 期’僅金屬層受到硏磨，大量之金屬離子或金屬氧化物離 子等副產物溶解於硏磨液中，硏磨液之阻抗相對地會降 低。然而當硏磨至接近硏磨終止層時，部分介電層因硏磨 而露出，相對地金屬離子或金屬氧化物離子等副產物的數 量變少，同時亦會產生少量介電層與硏磨液反應產生之副 產物，因此硏磨液之阻抗會對應地降低。因此，藉由監測 硏磨後硏磨液之阻抗値，便可以推測硏磨狀態，並判斷硏 磨終點。 朽："部十--^c^^h ηίνί贤合 0.^印*';^ ---------表-- (誚先閱讀背面之注意事項再填寫本頁} 依照本發明之硏磨終點監測方法，可在硏磨機台上之 適當位置’設置終點監測裝置，針對硏磨後之硏磨液進行 阻抗監測。請參照第3圖，其所繪示爲依照本發明之化學 機械硏磨法件終點監測裝置之結構示意圖。化學機械硏磨 機台包括硏磨台4〇，其上配置有硏磨墊42，硏磨時硏磨 台4〇連同硏磨墊42循一定方向旋轉（如第3圖中之44)。 硏磨液供應裝置5〇(SlUrry Supply)，係用以提供硏磨時所 需之硏磨液52(Slmry)於硏磨墊42表面。晶片夾持器46 則是用以夾持欲硏磨之晶片48，其結構比如爲第2A圖所 示的雙金屬鑲嵌結構，而將金屬層（第2A圖之30)表面， 朝向硏磨墊42，將其壓按於硏磨墊42上，並使晶片48表 面與硏磨墊42間充滿硏磨液52。硏磨時晶片夾持器46連 同晶片48 ’循一定方向旋轉(如第3圖中之54所示），使 9 本紙張尺度迪扣中固國家標準（CNS ) Λ4規格（210X297公釐） 4403tw i'.doc/008 _______________. _______________________________ B7 五、發明说明（g ) ~~~~~ ---------於-- (誚先閱讀背面之注意事項再读寫本頁) 得晶片48與硏磨墊42間產生相對運動，利用硏磨液52 及硏磨墊42之作用，進行硏磨。一般晶片夾持器46還包 括一護環56(Retammg Ring)，圍繞於晶片48之外圍，用 以保護晶片48之周緣。至於硏磨液π，由於硏磨台4〇之 旋轉，而流入硏磨墊42與晶片48間，而由於晶片夾持器 46與硏磨台40之旋轉，而向硏磨墊42外緣流出，由硏磨 液收集裝置58收集。 本發明之終點監測裝置’主要是針對硏磨後之硏磨液 作監測，因此其在化學機械硏磨機台上配置位置，只要在 硏磨後之硏磨液所流經之路徑上任何位置皆可。舉例來 說，硏磨終點監測裝置可配置於硏磨台4〇上，較佳是靠 近硏磨台4〇邊緣之位置（如第3圖之62a所示）。亦可以配 置於硏磨液收集裝置58中（如第3圖之62b所示），直接對 硏磨後之硏磨液進行監測，當然也可以配置於護環56上。 在此以配置於護環56上爲例，說明本發明硏磨終點監測 裝置之結構。請黎照第4圖，其所繪示爲相對於第3圖中 60所不方向，護環之仰視圖。本發明之硏磨終點監測裝置 係在護環56上形成一溝槽64’而溝槽64中配置二電極 66a、66b，藉由線路連接至一阻抗量測裝置68。當硏磨渦 程中硏磨後之硏磨液會流入溝槽M中，而充滿於二電^ 66a; 66b間，透過阻抗量測裝置68則可即時量測到硏磨 液之阻抗，因而硏判硏磨狀態。 藉由本發明所提出之硏磨終點監測裝置，可以即時監 測硏磨中之硏磨液阻抗，以推斷硏磨狀態，進而有效掌握 本紙张尺度過州中國國家標準（CNS ) Λ4規格（210X 297公釐） A7 B7 五、發明説明（q ) 硏磨終點，避免凹陷或侵蝕現象發生。 雖然本發明已以一較佳實施例揭露如上，然其並非用 以限定本發明，任何熟習此技藝者，在不脫離本發明之精 神和範圍內’當可作些許之更動與潤飾，因此本發明之保 護範圍當視後附之申請專利範圍所界定者爲準。 4 4 03twr.doc/00 8 本紙张尺度適ffl中闼國家標準（CNS ) Λ4規格（210X297公釐） (讀先閱讀背面之注意事項再：¾:寫本頁) i、.1T 4403t \ v i .doc / 0 () S A 7 V. Description of the invention (t) _ --- = according to the present invention-= preferred axis _-A cross section of a double gold display process is shown. The metal-to-metal A technology is commonly used in high-concentration semiconductor processes. There is at least a metal layer a on the substrate 20, such as brocade, and a dielectric layer 24, such as an oxide layer, is deposited on the metal layer 22. The secondary lithography process was used to form the openings 26a, 28 and 28. The openings were used as the interlayer window connecting the metal layer 22, and the openings 28 and 28 were used to connect the conductive material as a metal interconnect. Line (interc〇nnection). Then, the deposited metal layer 30, such as copper, is used to fill the openings 26a, j6b, and 28, and a chemical mechanical honing process is performed. The portion of the metal layer 30 above the dielectric layer 24 is used at this time. The dielectric layer μ serves as a honing stop layer. After the honing is completed, a metal plug 32a is formed in the openings 26a, 26b; and a metal plug 32b is formed in the opening 28. Generally, honing fluid (Slurry) usually includes two kinds of composition: one is a chemically active component (chemically active component) including an acid or an aqueous solution; an oxidizing agent such as iron cyanide (〇 ^) and a complexing agent ((: 0qing1 to 1 ^ 1 ^ post), such as heat, THF, DMSO temple. The other is a mechanically active component (Mechanically Active Component) such as silicon dioxide particles, alumina particles, silicon carbide particles, etc. (Abrasive). During the honing process, the metal layer will react with the acid or alkali or the oxidant in the honing fluid to dissolve in the honing fluid. For example, copper will be oxidized into copper oxide ions or cuprous ions and dissolved in the honing fluid. Tungsten will oxidize into tungsten oxide ions and dissolve in the honing fluid. I found that during the honing process, the honing fluid will produce different by-products (such as copper oxidation) for thin film layers of different materials. Ions, tungsten oxide ions, and these by-products have their electrical conductivity 8 paper size Cheng / 1] China National Standard (CNS) A4 specifications (210X297 mm) --------- each-(阅读 Read the notes on the back before filling This S) set 4403i \ v) '. Doc / 008 V. invention described billion) of thus dissolved solution WH mill grinding fluid will change the impedance value of WH. Therefore, the resistance of the honing fluid after honing can be used as an indicator of the honing end point. Taking the chemical-mechanical honing in the above bimetal mosaic as an example, in the early stage of honing, only the metal layer was honed, and a large amount of by-products such as metal ions or metal oxide ions were dissolved in the honing liquid, and the resistance of the honing liquid was Relatively lower. However, when the honing is close to the honing end layer, part of the dielectric layer is exposed due to honing, and the amount of by-products such as metal ions or metal oxide ions is relatively small, and a small amount of the dielectric layer and honing will also be generated. As a by-product of the liquid reaction, the resistance of the honing liquid will correspondingly decrease. Therefore, by monitoring the resistance of the honing fluid after honing, the state of honing can be estimated and the end point of the honing can be judged. Decay: " 部 十-^ c ^^ h ηίνί 贤 合 0. ^ 印 * '; ^ --------- 表-(诮 Please read the precautions on the back before filling this page} In the honing end point monitoring method of the present invention, an end point monitoring device can be provided at an appropriate position on the honing machine table to perform impedance monitoring on the honing fluid after honing. Please refer to FIG. 3, which is shown in accordance with this Schematic diagram of the structure of the end-point monitoring device for the chemical mechanical honing method of the invention. The chemical mechanical honing machine table includes a honing table 40, on which a honing pad 42 is arranged, and the honing table 40 is honed together with the honing pad 42 Rotate in a certain direction (such as 44 in Figure 3). The honing liquid supply device 50 (SlUrry Supply) is used to provide the honing liquid 52 (Slmry) required for honing on the surface of the honing pad 42. The wafer holder 46 is used to hold the wafer 48 to be honed. Its structure is, for example, a bimetal mosaic structure shown in FIG. 2A, and the surface of the metal layer (30 in FIG. 2A) is facing the honing pad. 42. Press it on the honing pad 42 and fill the surface of the wafer 48 with the honing pad 52 with the honing liquid 52. During the honing, the wafer holder 46 and the wafer 48 are cycled through. Rotate in the direction (shown as 54 in Figure 3) to make the 9-paper standard Disu Zhonggu National Standard (CNS) Λ4 specification (210X297 mm) 4403tw i'.doc / 008 _______________. _______________________________ B7 V. Description of the invention (G) ~~~~~ ----------- (诮 Read the precautions on the back before reading and writing this page) The relative motion between the wafer 48 and the honing pad 42 is obtained, and the honing is used. The liquid 52 and the honing pad 42 perform honing. Generally, the wafer holder 46 also includes a retaining ring 56 (Retammg Ring) surrounding the periphery of the wafer 48 to protect the periphery of the wafer 48. As for the honing fluid π flows into the honing pad 42 and the wafer 48 due to the rotation of the honing table 40, and flows out to the outer edge of the honing pad 42 due to the rotation of the wafer holder 46 and the honing table 40, and is honed by the honing The liquid collection device 58 collects. The end point monitoring device of the present invention is mainly used for monitoring the honing liquid after honing. Therefore, it is arranged on the chemical mechanical honing machine table as long as the honing liquid flows after the honing. Any position on the path can be passed. For example, the honing end point monitoring device can be configured in On the grinding table 40, preferably near the edge of the honing table 40 (as shown in 62a in FIG. 3). It can also be arranged in the honing liquid collection device 58 (as shown in 62b in FIG. 3) To directly monitor the honing fluid after honing, of course, it can also be arranged on the guard ring 56. Here, the configuration on the guard ring 56 is taken as an example to explain the structure of the honing end point monitoring device of the present invention. FIG. 4 is a bottom view of the retaining ring with respect to direction 60 in FIG. 3. The honing end point monitoring device of the present invention is formed with a groove 64 'on the guard ring 56 and two electrodes 66a, 66b are arranged in the groove 64, and are connected to an impedance measurement device 68 through a line. When the honing fluid after honing during the honing vortex will flow into the groove M, and it will be filled between the two electricity ^ 66a; 66b, through the impedance measurement device 68, the impedance of the honing fluid can be measured in real time. Honed state. With the honing end point monitoring device provided by the present invention, the honing fluid impedance in honing can be monitored in real time to infer the honing state, and the paper size can be effectively controlled by the Chinese National Standard (CNS) Λ4 specification (210X 297) (Centi) A7 B7 5. Description of the invention (q) Honing end point to avoid sinking or erosion. Although the present invention has been disclosed as above with a preferred embodiment, it is not intended to limit the present invention. Anyone skilled in the art can make some modifications and retouching without departing from the spirit and scope of the present invention. The scope of protection of the invention shall be determined by the scope of the attached patent application. 4 4 03twr.doc / 00 8 This paper is suitable for ffl China National Standard (CNS) Λ4 specification (210X297 mm) (read the precautions on the back before reading: ¾: write this page) i ..
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