1270135 16154twf.doc/g 九、發明說明： 【發明所屬之技術領域】 本發明是有關於一種化學機械研磨製程，且特別是有 關於化學機械研磨製程以及增加其研磨終點準確性的方 法。 - 【先前技術】 • 卩过著半導體製程技術的蓬勃發展，晶片上單位面積所 參 旎製作的電晶體數量也越來越多，元件的積集度高，越是 無法容忍晶片表面的不平坦情形，對於晶片表面平坦度的 • 需求也愈益升高。化學機械研磨法（chemical meehariieal Polishing)能夠提供良好的全面性表面均勾化，已經成為 洙次微米製程當中，不可或缺的薄膜平坦化技術。 以苇見之鎢插基的化學機械研磨製程為例，請參照圖 1A。圖1A疋繪不習知金屬内連線的結構剖面圖。晶片 之基底101"上有一層氧化石夕層111。氧化石夕層111中具有 開口 13〇氧化發層111上覆蓋了一層黏著層140，黏著層 140的材質例如是氮化鈦/鈦（TiN/Ti)。黏著層140上為 導體層150，導體層15〇的材質例如是鶴。開〇 13〇是作 '為f觸窗開口（contacthole)之用，開口 130内所填滿的 - 黏者層140與導體層150係作為導電插塞之用。由於氧化 f層U1表面，還會形成導線以連接各個導電插塞，因此， 氧化夕層111表面上之黏著層與導體層皆須以 學機械研磨製程去除之。 為了避免化學機械研磨製程過早結束或研磨過久而導 1270135 16154twf.doc/g 致殘留、内凹(dishing)或是絕緣體腐钱(erosi〇n)等問題，如 何準確地偵測研磨終點，是化學機械研磨製程的研究重點 之一。目别業界常用來偵測研磨終點的方法，就是利用一 紅外光雷射照射導體層150，於待研磨層（如圖ία中之導 體層150與黏著層14〇)進行化學機械研磨製程當中，持 續偵測紅外光雷射照射待研磨層所得之反射強度。由於待 研磨層的材質多半包含有金屬，氧化矽層ln為非金屬， 因此，紅外光雷射對於待研磨層的反射強度，會遠大於光 束對於氧化石夕層111的反射強度。故而，當偵測到反射強 度，然有下降的趨勢，便可以推知待研磨層皆已移除，而 暴露出氧化矽層111的表面，此時即為化學機械研磨製 之研磨終點。 另方面，奴著積體電路的蓬勃發展，對於元件積集 度的要求越來越高，線寬縮小的結果，使得微影製程的Ξ 難度增加’料發生解失誤的情形。尤其，於綱 反射I·生的材貝’例如金屬或多晶石夕的時候，這些材質合八 曝光光源容隸縣表面發生反射，造成光阻層尺寸^ 偏差，導賴轉料正確。為防止 1斤 通常會在膜層上形成—屛於埒蚪@ / · 出現1270135 16154twf.doc/g IX. Description of the Invention: [Technical Field of the Invention] The present invention relates to a chemical mechanical polishing process, and more particularly to a chemical mechanical polishing process and a method of increasing the accuracy of the polishing end point thereof. - [Prior Art] • With the rapid development of semiconductor process technology, the number of transistors produced per unit area on the wafer is increasing, and the accumulation of components is high. The more unacceptable the unevenness of the wafer surface In this case, the demand for wafer surface flatness is also increasing. Chemical meehariieal Polishing provides a good overall surface finish and has become an indispensable film planarization technology in the sub-micron process. For example, a chemical mechanical polishing process for a tungsten insert is shown in Fig. 1A. Figure 1A is a cross-sectional view showing the structure of a conventional metal interconnect. There is a layer of oxidized stone layer 111 on the substrate 101" of the wafer. The oxidized stone layer 111 has an opening. The oxidized layer 111 is covered with an adhesive layer 140. The material of the adhesive layer 140 is, for example, titanium nitride/titanium (TiN/Ti). The adhesive layer 140 is a conductor layer 150, and the material of the conductor layer 15 is, for example, a crane. The opening 13 is used for the 'contact hole', and the adhesive layer 140 and the conductor layer 150 filled in the opening 130 serve as conductive plugs. Since the surface of the f layer U1 is oxidized, wires are also formed to connect the respective conductive plugs. Therefore, the adhesive layer and the conductor layer on the surface of the oxidized layer 111 must be removed by a mechanical polishing process. How to accurately detect the grinding end point in order to avoid problems such as residual, dishing or erosi〇n caused by the premature end of the chemical mechanical polishing process or the long-term grinding process, It is one of the research focuses of the chemical mechanical polishing process. The method commonly used in the industry to detect the polishing end point is to irradiate the conductor layer 150 with an infrared laser, and perform a chemical mechanical polishing process on the layer to be polished (the conductor layer 150 and the adhesive layer 14 in FIG. The intensity of the reflection of the laser beam to be polished is continuously detected by the infrared light. Since the material of the layer to be polished mostly contains metal, the yttrium oxide layer ln is non-metal, and therefore, the intensity of the infrared laser for the layer to be polished is much greater than the intensity of the beam for the oxidized layer 111. Therefore, when the reflection intensity is detected, there is a tendency to decrease, and it can be inferred that the layer to be polished has been removed, and the surface of the ruthenium oxide layer 111 is exposed, which is the polishing end of the chemical mechanical polishing. On the other hand, the vigorous development of the slave integrated circuit has become more and more demanding on the component accumulating degree, and the result of the narrowing of the line width has increased the difficulty of the lithography process. In particular, when the material of the reflection I· raw material, such as metal or polycrystalline stone, is used, the surface of these materials is reflected by the surface of the Rongxian County, causing the deviation of the size of the photoresist layer and correcting the transfer. In order to prevent 1 kg, it usually forms on the film layer - 屛于埒蚪@ / · appears
日抗反射層（ant卜reflection coating layer) ( dielectHc anti.eflect J = 1少反射光於㈣時對光阻曝光之精確 度斤仏成的决差，進而提高元件的良率。 雖然抗反射層或是介雷# p 存在的必要性，^ Γ 層對於微影製程有其 i疋，如此—來，也製造了新的問題。那 1270135 16154twf.doc/g 就是’當我們使用化學機械研磨法進行平坦化步驟之時， 可能由原先的單層氧化矽層111，變成如圖1B所示之材料 層120。材料層120由基底101起例如是氧化矽層lu、第 一介電質抗反射層113、第二介電質抗反射層ι15與頂蓋 氧化層（cap oxide layer) 117。這些膜層將導致紅外光雷 射的反射強度，不如原先那麼規律，待研磨層厚度降低， 反射強度反而可能會上升，造成反射強度紊亂的現象。這 種現象將使得我們無法判斷研磨終點。如果研磨終止過 早，則會在材料層120上產生導體層150之殘留，可能造 成橋接現象(bridge)。相反的，如果研磨終止過晚，則會造 成材料層120侵钱現象(erosi〇n)，使得材料層丨2〇同時遭 到研磨而變薄，且造成導體層150亦過度研磨，甚至在積 集度較南的元件，還會造成金屬内連線間的介電物質不 足，而影響元件操作。 【發明内容】 有鑑於此，本發明的目的就是在提供一種化學機械研 磨製程以及增加其研磨終點準確性的方法，能夠避免偵測 強度紊亂不明的問題，有效增進化學機械研磨製程的研磨 終點之偵測。 本發明提出一種增加化學機械研磨製程之研磨終點準 確性的方法，此方法係於化學機械研磨製程之前進行，其 步驟包括⑻提供一測試片，測試片上已形成有待研磨層以 及位於待研磨層下方之材料層；（b)提供具有一波長之測試 光束，照射測試片；（c)對測試片進行化學機械研磨製程， 1270135 16154twf.doc/g 移除待研磨層，直到暴露出材料層為止 測測試光束於研磨#. 磨声即將^^ 射強度，以及刚斷於待研 而二士 Γ王私除’而越接近待研磨層與材料層之間的介 漸升::走:;反，強度趨勢，判斷結果若是反射強度有逐 勢，則重複步驟⑻至步選擇另一測試片 =2^進行另—反射強度的判斷，直到反射強度 之赵势為一逐漸下降的趨勢。 依照本發_實_所叙增純 3終=確=方法，上述具有波長之測試光^由ΐ 早波長之化學機械研磨機台所提供。上述之測 也可以^由具有多數波長之化學機械研磨機台所提供。 依照本發_實_所述之增加化 研磨終點準確性的方法，上鱗研磨層即將 =測強度’與尚未進行化學機械研磨製程時^ 偵測到的反射強度相比，至少降低〇 17。 依照本發_實施例所述之增加化學機械研磨製程之 ’上述於重鮮:欠步驟⑻到步驟⑷ 單:：反 浐中 取夕之波長，用於後縯的研磨製 依照本發_實施例所述之增純學機械研磨 ，終點f確㈣方法’上述待研磨層之材質可以是金 屬’例如疋鶴、欽或銅。 一 依照本發明的實施例所述之增加化學機械研磨製程之 1270135 16154twf.doc/g 研磨終點準確性的方法，上述材料層可以包括一層抗反射 (触-reflection coating，ARC)層。此外，上述材料層還 可以包括一層介電質抗反射（dielectHc⑽ ⑽tmg，DARC )層。介電質抗反射層之材質例如是氮化石夕 或氮氧化石夕。另外，上述材料層更可以包括一頂蓋氧化層 一 (cap oxide layer ) ° • 本發明提出一種化學機械研磨製程。其步驟包括：首 # 先提供多數片晶圓，且各晶圓上已形成有待研磨層以及位 於待研磨層下方之材料層。然後，選取至少一片晶圓，進 行預研磨步驟，以決定出用於摘測研磨終點之债測波長。 其:在進行預研磨步驟中，利用债測波長持續偵測研磨中 的晶圓，直到移除晶圓上之待研磨層而暴露出材料層為 止。並且由偵測波長所獲得的反射強度趨勢，其於待ς磨 層2將完全移除，而越接近待研磨層與材料層之間的介面 的時期，有逐漸減小的趨勢。繼而，研磨剩餘之晶圓，並 修 利用偵測波長之光束偵測研磨終點。 依照本發明的實施例所述之化學機械研磨製程，上述 預研磨步驟包括：（a)提供至少一片晶圓；（b)提供具有一波 • 長之測試光束，照射此晶圓；（c)對晶圓進行預研磨製程， , 以移除待研磨層，直到暴露出材料層為止，並且同時持續 偵測測試光束於研磨製程中的反射強度；以及(幻判斷於待 研磨層即將完全移除，而越接近待研磨層與材料層之間的 介面的這時期之反射強度趨勢，若反射強度有逐漸升高的 趨勢，則重複步驟(a)至步驟(d)，選擇另一片晶圓及另一波 1270135 ^IS^f.doc/g 長’以進行另一反射強度的判斷，直到反射強度有逐漸下 降的趨勢。 依照本發明的實施例所述之化學機械研磨製程，上述 具有波長之測試光束，可以是由具有單一波長之化學機械 研磨機台所提供。此外，上述測試光束也可以是由具有多 數波長之化學機械研磨機台所提供。 • ^ 依照本發明的實施例所述之化學機械研磨製程，上述 待研磨層即將被完全移除時所偵測到的反射強度，與尚未 進行預研磨製程時所彳貞測到的反射強度相比、、，至少降低 ， 0.17。 _ 依照本發明的實施例所述之化學機械研磨製程，上述 於重複多次步驟(a)到步驟(d)之後，得到多數組反射強度之 數據，選擇這些數據當中，單位時間内反射強度下降最多 之波長，為偵測波長。 依照本發明的實施例所述之化學機械研磨製程，上述 • 待研磨層之材質例如包含有金屬，如鎢、鈦或銅。材料層 包括一介電質抗反射層，介電質抗反射層之材質例如是氮 化矽、氮氧化矽。 • 树日⑽研磨製程之前，先進行波長職，以決定出 特定波長之光束。之後，再利用此特定波長之光束進行後 績之=學機械研磨製程之研磨終點的監測，因此，即使基 底上還設置有多層抗反射層，仍舊得以準確地監測出化學 機械研磨製程的研磨終點。研磨終點的偵測並不會因為其 他膜層的設置，而產生反射強度紊鼠的現象，故而得以依The anti-reflective layer (anti-reflection coating layer) (dielectHc anti.eflect J = 1 less reflected light in (4) the accuracy of the exposure to the photoresist, thus improving the yield of the component. Although the anti-reflection layer Or the necessity of the existence of #雷# p, ^ Γ layer has its effect on the lithography process, so - also created a new problem. That 1270135 16154twf.doc / g is 'when we use chemical mechanical polishing When the planarization step is performed, it may be changed from the original single-layer yttrium oxide layer 111 to the material layer 120 as shown in FIG. 1B. The material layer 120 is made of the substrate 101, for example, a yttrium oxide layer, a first dielectric anti-reflection. The layer 113, the second dielectric anti-reflective layer ι15 and the cap oxide layer 117. These layers will cause the reflection intensity of the infrared light laser to be less regular, the thickness of the layer to be polished is reduced, and the reflection intensity is On the contrary, it may rise, causing a disorder of the reflection intensity. This phenomenon will make it impossible for us to judge the polishing end point. If the polishing is terminated too early, the residue of the conductor layer 150 may be generated on the material layer 120, possibly causing a bridge. In contrast, if the grinding is terminated too late, the material layer 120 will be invaded, causing the material layer to be thinned at the same time and causing the conductor layer 150 to be excessive. Grinding, even in components with a relatively concentrated degree, may result in insufficient dielectric material between the metal interconnects and affect component operation. SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to provide a chemical mechanical polishing. The process and the method for increasing the accuracy of the polishing end point can avoid the problem that the detection intensity is unclear, and effectively improve the detection of the polishing end point of the chemical mechanical polishing process. The invention provides a method for increasing the accuracy of the polishing end point of the chemical mechanical polishing process. The method is performed before the chemical mechanical polishing process, and the steps include (8) providing a test piece on which a layer to be polished and a material layer under the layer to be polished are formed; (b) providing a test beam having a wavelength, and irradiating Test piece; (c) chemical mechanical polishing process of the test piece, 1270135 16154twf.doc/g to remove the layer to be polished, The test beam is measured until the material layer is exposed. The grinding sound is about to be the same as the intensity of the shot, and the distance between the layer to be polished and the material layer is gradually increased. :: go:; reverse, intensity trend, if the reflection result has a potential, then repeat step (8) to step to select another test piece = 2^ to judge the intensity of the other reflection until the reflection intensity is gradually The downward trend. According to the method of increasing the purity of the present invention, the above test light having a wavelength is provided by a chemical mechanical polishing machine of the early wavelength. The above measurements can also be provided by a chemical mechanical polishing machine having a majority of wavelengths. According to the method of increasing the accuracy of the polishing end point described in the present invention, the upper scale polishing layer is to be at least lower than the detected intensity of the detected intensity when the chemical mechanical polishing process has not been performed. According to the method of the present invention, the chemical mechanical polishing process is increased by the above-mentioned "re-freshing: under-step (8) to step (4) single:: the wavelength of the eclipse in the retort, and the polishing system for the post-action is performed according to the present invention. For example, the mechanical polishing of the purity, the end point f (four) method 'the material of the layer to be polished may be metal 'such as 疋 crane, chin or copper. A method of increasing the accuracy of a 1270135 16154 twf.doc/g polishing end point of a CMP process according to an embodiment of the invention, the material layer may comprise an anti-reflection coating (ARC) layer. In addition, the material layer may further comprise a layer of dielectric anti-reflection (dielectHc(10) (10) tmg, DARC). The material of the dielectric anti-reflection layer is, for example, nitride or arsenic oxide. Further, the above material layer may further include a cap oxide layer. The present invention proposes a chemical mechanical polishing process. The steps include: first # first providing a plurality of wafers, and each layer has a layer to be polished and a layer of material under the layer to be polished. Then, at least one wafer is selected and a pre-grinding step is performed to determine the debt measurement wavelength for the end of the grinding. It is: in the pre-grinding step, the wafer in the grinding is continuously detected by the debt measurement wavelength until the layer to be polished on the wafer is removed to expose the material layer. And the tendency of the reflection intensity obtained by detecting the wavelength is completely removed when the layer to be honed 2 is completely removed, and the period closer to the interface between the layer to be polished and the layer of material has a tendency to gradually decrease. The remaining wafer is then ground and the end of the grinding is detected using a beam of detected wavelength. According to the CMP process of the embodiment of the invention, the pre-grinding step comprises: (a) providing at least one wafer; (b) providing a test beam having a wave length, illuminating the wafer; (c) Pre-polishing the wafer to remove the layer to be polished until the material layer is exposed, and at the same time continuously detecting the intensity of the reflection of the test beam in the polishing process; and (the illusion is that the layer to be polished is about to be completely removed) And the closer to the trend of the reflection intensity of the interface between the layer to be polished and the material layer, if the intensity of the reflection gradually increases, repeat steps (a) to (d) to select another wafer and Another wave 1270135 ^IS^f.doc / g length 'to make another reflection intensity judgment until the reflection intensity has a tendency to gradually decline. According to the embodiment of the present invention, the chemical mechanical polishing process, the above wavelength The test beam can be provided by a chemical mechanical polishing machine having a single wavelength. In addition, the test beam can also be provided by a chemical mechanical polishing machine having a plurality of wavelengths. According to the CMP process of the embodiment of the present invention, the intensity of the reflection detected when the layer to be polished is to be completely removed is compared with the intensity of the reflection when the pre-grinding process has not been performed. , at least, 0.17. _ According to the chemical mechanical polishing process of the embodiment of the present invention, after repeating steps (a) to (d) a plurality of times, data of multi-array reflection intensity is obtained, and the data is selected. The wavelength at which the reflection intensity decreases most per unit time is the detection wavelength. According to the chemical mechanical polishing process of the embodiment of the present invention, the material of the layer to be polished includes, for example, a metal such as tungsten, titanium or copper. The material layer comprises a dielectric anti-reflection layer, and the material of the dielectric anti-reflection layer is, for example, tantalum nitride or hafnium oxynitride. • Before the tree (10) polishing process, the wavelength is used to determine the beam of a specific wavelength. After that, the beam of the specific wavelength is used to perform the monitoring of the polishing end of the mechanical polishing process, so that even if the substrate is provided with a plurality of anti-reverse Layer, still able to accurately monitor the polishing end point of chemical mechanical polishing process. Polishing endpoint detection because it does not set his film layer, and a phenomenon reflected intensity tangled rats, and therefore is by
1270135 16154twf.doc/g 照元件的設計完成整個元件，避免橋接、短路等問題，提 高元件的可靠度與產品的良率。 為讓本發明之上述和其他目的、特徵和優點能更明顯 易懂，下文特舉實施例，並配合所附圖式，作詳細說明如 下。 【實施方式】 本發明之增加化學機械研磨製程之研磨終點準確性的 方法係於化學機械研磨製程之前進行。其詳細說明如下。 圖2所纷福本發明—實補之―種增加化學機械研磨製 程之研磨終點準確性的方法之步驟流程圖。圖3為依照^ 發明一實施例所繪示之測試片結構剖面圖。 請參照圖2與目3，首先提供一測試片·，測試片 300上已形成有待研磨層31〇以及位於待研磨層31〇下方 之材料層320 (步驟201)。待研磨層310例如i包括-居 黏著層34〇與-層導體層35〇。黏著層姻的材質例如丄 鈦化氮/鈦（TiN/Ti)。導體層35〇之材質例如是嫣 德蓉導雷姑料。 材料層320由基底301起則可以包括介電層3ΐι、介 電質抗反射層313、抗反射層315與頂蓋氧化層η?。 層311的材質例如是氧化石夕。介電質抗反射層犯之材質 例如是氮彳㈣、氮氧切、氧切或是 反 射層315之材質例如是鈦、氮化鈦、鈦鎢合金、魏鋅或 是其他適當材質。上述之待研磨層31Q是以導體層35卜 黏著層340 ’材料層320是以介電層3ιι、介電質抗反射層 11 1270135 16154twf.doc/g 313、抗反射層315與頂蓋氧化層317為例作說明，缺而， 待研磨層310與材料層320當純可以是由其他膜層或其 他材質所構成，端視元件之需要而定。此外，介電質抗反 射層313、抗反射層315例如是之前之微影與細製^所 殘留下來之膜層。 接著，提供具有-波長之測試光束，照射測試片3〇〇 (步驟205 )。然後’對測試片3〇〇進行化學機械研磨製程， 參移除f研磨層31〇，直到暴露出材料層320為止，並且同 時持縯侧測試光束於研磨製程中，照射測試片綱表面 (即待研磨層310表面）所得的反射強度（步驟211)。 繼而，判斷於待研磨層310即將完全移除，而越接近 待研磨層310與材料層32〇之間的介面的這時期之反 度趨勢（步驟215)。 身又來說，為了提高微影製程的準確度，材料層32〇 中之膜層，已不若習知之材料層（如先前技術中之介電層 =0)那樣單純。本實施例中，材料層32〇例如是包含了介 電層311、介電質抗反射層313、抗反射層315與頂蓋氧化 層317因此，光束在照射測試片300時所產生的反射強 度，隨著膜層之研磨，可能會有上升的趨勢，而產生反射 強度紊亂，不易判斷研磨終點的問題。故而，假若這段時 期之反射強度，有逐漸升高的趨勢（步驟221)，這時， 就需要選擇另一測試片及另一波長，以不同波長之光束重 複步驟2(U、步驟2〇5、步驟211與步驟215，進行另一反 射強度的判斷，直到反射強度的趨勢為逐漸下降的趨勢。 12 1270135 16154twf.doc/g 當然’另一片測試片與原本的測試片結構相同，如此才能 夠測試出合適的波長。 右是反射強度有逐漸下降的趨勢（步驟231)，即可選 定此波長之測試光束，用於偵測後續化學機械研磨製程的 研磨終點。在一實施例中，待研磨層即將被完全移除時所 偵測到的反射強度，與尚未進行化學機械研磨製程時所偵 測到的反射強度相比，至少是降低了 〇·17。 值得一提的是，雖然說反射強度逐漸下降之光束，才 適於用來偵測化學機械研磨製程的研磨終點。'但是，假使 反射強度下降的幅度越大，自然也就越容易準確偵測研磨 終點。因此，於多次重複步驟2(η、步驟2〇5、步驟2ιι、 步驟215之後，可以得到多組反射強度之數據，選擇這些 ^據當中，單位時間内反射強度下降最多之波長，用於後 續的研磨製程。由於這個波長既然是在待研磨層即將完全 移除時，單位時間内反射強度下降最多的波長，則以此= 長之光束來偵測研磨終點，將會是最恰當、最容易準確偵 測研磨終點的波長，也就能夠增加化學機械研磨製程之研 磨終點的準確性。 、；另外特別注思的是，測試光束係由一研磨機台上之 光學儀器所提供。光學儀器可以只提供具有一特定^長之 ，士，這時，改變偵測光束之波長的方法，就是要提^另 具有另一特定波長之研磨機台。當然，研磨機台:之 光=儀器也可以是一台能夠提供多數個不同波長之&束， 此時，欲改變偵測光束之波長的方法便可以直接操作調 13 1270135 16154twf.doc/g 整，而轉換成另一個波長以進行測試。 因此，本發明因於研磨製程之前，先進行 以決定出特定波長之光束。之後，再利用此特定=光 束進行後續之化學機械研磨製程之研磨終點的監測，因 此，能夠增加化學機械研磨製程之研磨終點準確性。 、以下說明利用上述增加化學機械研磨製程之研磨终 點準確性的方法’所提出之一種化學機械研磨製程，並中 此化學機械研磨製程例如是應用於接觸窗製程中。圖. ^為本剌-實施例之—種化學機削㈣程的步驟流 程圖。 ，參關4,首先提供多片晶圓，各晶圓上已形成有 +研磨層以及位於待研磨層下方之材料層（步驟。 層5是層導體層與—層黏著層。導體層之 材貝例如疋鎢、銅、鎳等導電材料。黏著 ntm。材料層由基底起則可以包括介電層疋 反射層、抗反射層與頂蓋氧化層。介電層的材質 氧介電質抗反射層之材質例如是氮化石夕、氮 化石夕或是SixNy(0H)z。抗反射層之材質例如是 圓之二n鶴合金、石西化辞或是其他等適當材質。晶 口 。構㉔茶妝圖3之測試片結構剖面圖。 出用=，1遠取至少一片晶圓’進行預研磨步驟，以決定 測研磨終點之谓測波長（步驟405)。並中在進 仃預研磨步驟中，利用偵制油且杜这 八τ你延 直_夕除晶回上之待研磨層而暴露出材料層為止。並且由 14 1270135 16154twf.doc/g 偵測波長所獲得的一反射強度趨勢，其於待研磨層即將完 全移除，而越接近待研磨層與材料層之間的介面的時期， 有逐漸減小的趨勢。此預研磨步驟即為上述實施例中所揭 露的增加化學機械研磨製程之研磨終點準確性的方法。也 就是說，步驟405包含了上述實施例所提到的每一步驟， 不同的僅在於，上述實施例中之測試片1〇〇改為此處之晶 圓，故而步驟405在本實施例中就不再詳細贅述。 暴 繼而，研磨剩餘之晶圓，並利用偵測波長之光束偵測 研磨終點（步驟411)。值得一提的是，由於本發明在步 驟411之前，先進行波長測試，以決定出特定波長之光束 (步驟405)。之後，再利用此特定波長之光束進行步驟 411 ’因此，能夠增加化學機械研磨製程之研磨終點準確 性。此外’於研磨終點被偵測到之後，更可以對晶片進行 過度研磨（over-polishing)步驟（步驟421)以避免待研 磨層在材料層上留下殘餘，而造成橋接的現象。 _ 綜上所述，本發明因為於正式對晶圓進行化學機械研 磨製程之前，先進行預研磨步驟，先行測試出何種波長之 光束’對於晶片的反射強度，會隨著待研磨層被移除的時 候，產生劇烈的下降。以反射強度下降幅度最大的波長之 .光束’做為偵測後續化學機械研磨製程研磨終點的光束。 口此’即使待研磨層下方還設置有多層膜層，仍舊得以準 確地彳貞測出化學機械研磨製程的研磨終點。研磨終點的價 剩不會因為其他膜層的設置，而產生反射強度紊|L的現 象，故而得以依照元件的設計完成整個元件，避免橋接、 15 1270135 16154tvvf.doc/g 短路等問題，提高元件的可靠度與產品的良率。 ^外，在一實例中，晶圓中之待研磨層例如是包含有 欽的膜層，待研磨層下方之材料層例如是包含了兩層介電 裊抗反射層。於進行預研磨的過程中，以波長之紅 外光照射晶圓時，價測到的反射強度如圖5所示，當含欽 之待研磨層的厚度越接近〇nm，反射強度為一上升 勢、。，當選用其他波長，而以波長300mn以及波長365nm 之光束分別照射晶圓時，偵測到的反射強度如圖6 (波長 3〇〇腿）與圖7 (波長365麵）所示，當含欽之待研磨層 的厚度越接近〇nm，反射強度有關的下降_勢。由此 可知，波長300職、波長365麵與波長673職相比 舰長，可以用來侧此種晶圓於化學機械 f衣転中之研磨終點。因此，在進行研磨製程前，先利 i的=之方法來決定偵測波長，將有助於後續之研磨製 雖然本發明已以實麵難如上，然其麟用以限定 當視後附之申;專二本發明之保護範圍 【圖式簡單說明】 圖1A是緣示習知金屬插塞的結構剖面圖。 ，1B是緣示習知另-種金屬插塞的結構剖面圖。 磨為本發明一實施例之-種增加化學機械研 衣知之研磨終點準確性的方法之步驟流程圖。 16 1270135 16154twf.doc/g 圖3為依照本發明一實施例所繪示之測試片結構剖面 圖。 圖4所繪不為本發明一實施例之_種化學機械研磨製 程的步驟流程圖。 圖5所繪示為本發明一實施例，波長為673nm時，反 射強度對含鈦待研磨層的厚度之曲線圖。 圖6所繪示為本發明一實施例，波長為3〇〇nm時，反 m 射強度對含鈦待研磨層的厚度之曲線圖。 圖7所繪示為本發明一實施例，波長為365mn時，反 射強度對含鈦待研磨層的厚度之曲線圖。 【主要元件符號說明】 100 :晶片 300 :測試片 101、301 :基底 ill :氧化石夕層 113 :第一介電質抗反射層 115 :第二介電質抗反射層 117、317:頂蓋氧化層 120、320 :材料層 130 :開口 140、340 ··黏著層 150、350 :導體層 20卜 205、211、215、22卜23卜40卜 405、41卜415: 步驟 17 1270135 16154twf.doc/g 310 :待研磨層 311 :介電層 313 :介電質抗反射層 315 :抗反射層1270135 16154twf.doc/g The entire component is designed according to the component design, avoiding problems such as bridging and short circuit, and improving the reliability of the component and the yield of the product. The above and other objects, features and advantages of the present invention will become more <RTIgt; [Embodiment] The method of the present invention for increasing the accuracy of the polishing end point of the chemical mechanical polishing process is carried out before the chemical mechanical polishing process. The details are as follows. Figure 2 is a flow chart showing the steps of the method of increasing the accuracy of the grinding end point of a chemical mechanical polishing process. 3 is a cross-sectional view showing the structure of a test piece according to an embodiment of the invention. Referring to Figures 2 and 3, a test piece is first provided. The layer to be polished 31 is formed on the test piece 300 and the material layer 320 is located below the layer 31 to be polished (step 201). The layer to be polished 310, for example, i includes an adhesion layer 34 and a layer conductor layer 35. The material of the adhesive layer is, for example, niobium titanate/titanium (TiN/Ti). The material of the conductor layer 35 is, for example, 嫣德蓉导雷姑料. The material layer 320 from the substrate 301 may include a dielectric layer 3, a dielectric anti-reflective layer 313, an anti-reflective layer 315, and a cap oxide layer η. The material of the layer 311 is, for example, oxidized stone. The material of the dielectric anti-reflective layer is, for example, nitrogen (IV), oxynitride, oxygen-cut or reflective layer 315, such as titanium, titanium nitride, titanium-tungsten alloy, Wei zinc or other suitable materials. The above-mentioned layer to be polished 31Q is a conductor layer 35, and the material layer 320 is a dielectric layer 3, a dielectric anti-reflection layer 11 1270135 16154 twf.doc/g 313, an anti-reflection layer 315 and a cap oxide layer. For example, the 317 layer and the material layer 320 may be composed of other film layers or other materials, depending on the needs of the components. Further, the dielectric anti-reflection layer 313 and the anti-reflection layer 315 are, for example, film layers remaining in the previous lithography and fine film. Next, a test beam having a - wavelength is supplied, and the test piece 3 is irradiated (step 205). Then, a chemical mechanical polishing process is performed on the test piece 3, and the f-grinding layer 31 is removed until the material layer 320 is exposed, and at the same time, the side test beam is held in the polishing process to illuminate the surface of the test piece (ie, The resulting reflection intensity of the surface of the layer to be polished 310 (step 211). Then, it is judged that the layer to be polished 310 is about to be completely removed, and the closer to the period of the interface between the layer to be polished 310 and the layer of material 32 is reversed (step 215). In addition, in order to improve the accuracy of the lithography process, the film layer in the material layer 32 is not as simple as the conventional material layer (such as the dielectric layer =0 in the prior art). In this embodiment, the material layer 32 includes, for example, a dielectric layer 311, a dielectric anti-reflective layer 313, an anti-reflection layer 315, and a cap oxide layer 317. Therefore, the reflection intensity of the light beam when the test piece 300 is irradiated As the film is ground, there may be an upward trend, and the reflection intensity is disordered, and it is difficult to judge the end point of the polishing. Therefore, if the intensity of the reflection during this period has a tendency to gradually increase (step 221), then another test piece and another wavelength need to be selected, and step 2 is repeated with beams of different wavelengths (U, step 2〇5). Step 211 and step 215, another determination of the intensity of the reflection is performed until the trend of the reflection intensity is gradually decreasing. 12 1270135 16154twf.doc/g Of course, the other test piece has the same structure as the original test piece, so that The appropriate wavelength is tested. Right is the tendency of the reflection intensity to gradually decrease (step 231), and the test beam of this wavelength can be selected for detecting the polishing end point of the subsequent chemical mechanical polishing process. In an embodiment, to be ground The intensity of the reflection detected when the layer is about to be completely removed is at least reduced by 〇·17 compared to the intensity of the reflection detected when the chemical mechanical polishing process has not been performed. It is worth mentioning that although reflection The beam whose intensity is gradually decreasing is suitable for detecting the grinding end of the chemical mechanical polishing process. 'But, if the reflection intensity is reduced, the natural The easier it is to accurately detect the end point of the polishing. Therefore, after repeating step 2 (n, step 2〇5, step 2, and step 215 many times, data of multiple sets of reflection intensities can be obtained, and among these, the reflection per unit time is selected. The wavelength with the most drop in intensity is used for the subsequent grinding process. Since this wavelength is the wavelength at which the reflection intensity drops the most per unit time when the layer to be polished is to be completely removed, the long beam is used to detect the polishing end point. , will be the most appropriate and most accurate to accurately detect the wavelength of the grinding end point, which can increase the accuracy of the polishing end of the chemical mechanical polishing process. Also, in addition, the test beam is from a grinding machine. The optical instrument can provide only one specific length, and the method of changing the wavelength of the detection beam is to raise a grinding machine with another specific wavelength. Of course, the grinding machine Table: The light = the instrument can also be a beam that can provide a plurality of different wavelengths. At this time, the method of changing the wavelength of the detection beam can be Directly adjust the 13 1270135 16154twf.doc/g integer and convert it to another wavelength for testing. Therefore, the present invention is performed before the polishing process to determine the beam of a specific wavelength. Thereafter, the specific = beam is reused. Performing the monitoring of the polishing end point of the subsequent chemical mechanical polishing process, thereby increasing the accuracy of the polishing end point of the chemical mechanical polishing process. The following describes a method proposed by the above method for increasing the accuracy of the polishing end point of the chemical mechanical polishing process. The chemical mechanical polishing process, and the chemical mechanical polishing process is applied, for example, to a contact window process. Fig. ^ is a flow chart of the steps of the chemical milling (four) process of the embodiment - the reference 4, first provided A plurality of wafers have been formed with a +grinding layer and a layer of material underlying the layer to be polished (steps). Layer 5 is a layer conductor layer and a layer of adhesion layer. The material of the conductor layer is, for example, a conductive material such as tantalum tungsten, copper or nickel. Sticking ntm. The material layer may include a dielectric layer 反射 reflective layer, an anti-reflective layer, and a cap oxide layer from the substrate. Material of the dielectric layer The material of the oxygen-based anti-reflection layer is, for example, nitride nitride, nitrogen nitride or SixNy (0H)z. The material of the anti-reflection layer is, for example, a suitable material such as a two-neck alloy, a stone smear, or the like. Crystal mouth. A cross-sectional view of the test piece structure of Fig. 3 of Fig. The use of =, 1 far from at least one wafer is performed to perform a pre-grinding step to determine the measured wavelength of the polishing end point (step 405). In the pre-grinding step, the detector oil is used and the material layer is exposed to the layer to be polished. And a reflection intensity trend obtained by detecting the wavelength of 14 1270135 16154 twf.doc/g, which is gradually reduced when the layer to be polished is to be completely removed, and the closer to the interface between the layer to be polished and the material layer the trend of. This pre-grinding step is the method for increasing the accuracy of the grinding end point of the CMP process disclosed in the above embodiments. That is to say, step 405 includes each step mentioned in the above embodiment, except that the test piece 1 in the above embodiment is changed to the wafer here, so step 405 is in this embodiment. I won't go into details here. In the event of a storm, the remaining wafer is ground and the end of the grinding is detected using a beam of detected wavelength (step 411). It is worth mentioning that since the present invention precedes step 411, a wavelength test is performed to determine a beam of a particular wavelength (step 405). Thereafter, the light beam of this specific wavelength is used again to perform step 411'. Therefore, the accuracy of the polishing end point of the chemical mechanical polishing process can be increased. Further, after the polishing end point is detected, the wafer may be subjected to an over-polishing step (step 421) to prevent the layer to be ground from leaving a residue on the material layer, thereby causing bridging. In summary, the present invention performs a pre-grinding step before the chemical mechanical polishing process of the wafer is officially performed, and firstly tests which wavelength beam 'reflecting intensity for the wafer is moved along with the layer to be polished. In addition, there is a sharp drop. The beam, which is the wavelength at which the intensity of the reflection decreases the most, is used as a beam for detecting the end of the subsequent chemical mechanical polishing process. Even if a multi-layer film layer is provided under the layer to be polished, the grinding end point of the CMP process can be accurately determined. The price of the polishing end is not caused by the setting of other layers, but the phenomenon of reflection intensity ||L is generated. Therefore, the entire component can be completed according to the design of the component, avoiding the problem of bridging, short circuit, etc., and improving the component. Reliability and product yield. Further, in an example, the layer to be polished in the wafer is, for example, a film layer containing a film, and the material layer under the layer to be polished includes, for example, two layers of a dielectric anti-reflection layer. In the process of pre-polishing, when the wafer is irradiated with infrared light of a wavelength, the measured reflection intensity is as shown in FIG. 5. When the thickness of the layer to be polished is closer to 〇nm, the reflection intensity is increased. Potential. When other wavelengths are selected, and the light beams of 300 nm and 365 nm are respectively irradiated to the wafer, the detected reflection intensity is as shown in Fig. 6 (wavelength 3 〇〇 leg) and Fig. 7 (wavelength 365 plane), when The closer the thickness of the layer to be polished is to 〇nm, the decrease in the intensity of the reflection. It can be seen that the ship with a wavelength of 300, a wavelength of 365, and a wavelength of 673 can be used to polish the end of such a wafer in a chemical machine. Therefore, before the grinding process, the method of determining the detection wavelength will help the subsequent grinding system. Although the present invention has been difficult to achieve the above, the lining is used to limit the view. The scope of protection of the present invention [Simplified description of the drawings] Fig. 1A is a cross-sectional view showing the structure of a conventional metal plug. 1B is a structural sectional view showing a conventional metal plug. Milling is a flow chart of the steps of a method for increasing the accuracy of the polishing end point of a chemical mechanical coating according to an embodiment of the invention. 16 1270135 16154twf.doc/g FIG. 3 is a cross-sectional view showing the structure of a test piece according to an embodiment of the invention. Figure 4 is a flow chart showing the steps of a chemical mechanical polishing process which is not an embodiment of the present invention. Fig. 5 is a graph showing the reflection intensity versus the thickness of the layer to be polished containing titanium at a wavelength of 673 nm according to an embodiment of the present invention. Fig. 6 is a graph showing the inverse infrared intensity versus the thickness of the layer to be polished containing titanium at a wavelength of 3 〇〇 nm according to an embodiment of the invention. Fig. 7 is a graph showing the reflection intensity versus the thickness of the layer to be polished containing titanium at a wavelength of 365 nm according to an embodiment of the present invention. [Main component symbol description] 100: Wafer 300: Test piece 101, 301: Substrate ill: Oxide layer 113: First dielectric anti-reflection layer 115: Second dielectric anti-reflection layer 117, 317: Top cover Oxide layer 120, 320: material layer 130: opening 140, 340 · adhesive layer 150, 350: conductor layer 20 205, 211, 215, 22, 23, 40, 405, 41, 415: Step 17 1270135 16154twf.doc /g 310 : layer to be polished 311 : dielectric layer 313 : dielectric anti-reflection layer 315 : anti-reflection layer
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