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$法^— =hanical Pohshing，CMP) ’且特別是有關於一種銅 機械研磨方法。 于 【先前技術】 ,著7C件尺寸持續縮減，微影曝光解析度相對增加， =隨著曝光景深的輯’對於日日日圓表面之高低起伏輪摩的 ^忍要求更為嚴苛。化學機械研財法是目前能提供超大 里積體電路製程全域性平坦化(Gbbal ρι贿㈣丨㈣的技 術’它獨特的非等向性磨除性f除了用於晶圓表面輪扉之 平=化之外，亦可經由金屬研磨方式應用於垂直及水平金 屬導線連接(inte職neets)之製作、前段製程中元件 隔離製作及先進元件之製作、微機電彡 轉 示器製作等。 π卞囬.、、貝IX. Description of the Invention: [Technical Field of the Invention] The present invention relates to a chemical mechanical polishing method, and particularly relates to a copper mechanical polishing method. According to the [prior art], the size of the 7C piece continues to decrease, and the resolution of the lithography exposure is relatively increased. = With the exposure depth of field, the tolerance of the surface of the day and the sun is more severe. The chemical mechanical research method is currently available to provide the technology of the global planarization of the ultra-large integrated circuit process (Gbbal ρι bribe (4) 丨 (4). Its unique anisotropic wear-off f is used for wafer surface rim flattening. In addition to metallization, it can also be applied to the production of vertical and horizontal metal wire connections (inte neets), component isolation in the front-end process and the production of advanced components, micro-electromechanical transducer production, etc. Back.,, Bay
一般化學機械研磨設備基本上是由一個用來進行晶 片研磨的研磨台(PGlishing Table)，及—個用來承载被研: 晶1的研磨頭(Carrier)所組成。其中研磨頭將固定住晶片 的月面，然後把晶片的正面壓在舖有一層研磨墊(以他^ ⑽^研磨台上。當進行化學機械研磨時，研磨台將順著 一固疋方向旋轉’且研磨賴運動方向例如是線性 疋與研磨台-樣順著—固定方向旋轉且角速度相同，^ 外，進行研磨期間還包括加入研磨液(Slur ，以 曰 表面研磨。 疋仃曰日月 5 rf.doc/g 而目前在超大型積體電路（Ultra Large Scde Integration)發展到小於〇·ΐ3μιη的世代時，為提高晶片的執 行速度，需有效地克服阻抗等所造成之時間延遲，因此大 多採取低介電常數的材料及使用金屬銅作為内連線結構。 因此，關於金屬銅之化學機械研磨方法也在如火如^地發 展中。然而，目前的銅化學機械研磨方法常有研磨後的銅 缺漏(missing)情形亟待解決。 【發明内容】 本發明的目的就是在提供一種銅化學機械研磨方法， 可避免在化學機械研磨方法後有銅金屬層缺漏的情形發 生。 又 本呶明的再一目的疋提供一種銅化學機械研磨方法， 可選擇在不同研磨墊上進行不同階段研磨，以避免在化學 機械研磨方法後有銅金屬層缺漏的情形發生。 本發明提出一種銅化學機械研磨方法，適於平坦化一 銅金屬層，這層銅金屬層係覆蓋在具有一開口的一基底上 並填滿開口。這種方法包括先進行一第一階段研磨，以去 除銅金屬層的部分厚度，其中於第一階段研磨後，銅金屬 層殘留於基底表面的厚度在500〜4〇〇〇埃之間。然後再進 行一第二階段研磨，以完全去除開口以外之銅金屬'層。 依照本發明的較佳實施例所述的銅化學機械^磨方 法，上述之弟一與第二階段研磨的研磨速率可以相同，戋 是第一與第二階段研磨的研磨速率是不同的。 〆 本發明另提出一種銅化學機械研磨方法，適於平坦化 6 :wf.doc/g 一銅金屬層，這層銅金屬層係覆蓋在具有一開口的一基底 上並填滿開口。這種方法包括先提供一第一研磨墊，再於 第一研磨墊上進行一第一階段研磨，以去除銅金屬層的部 分厚度，其中於第一階段研磨後，銅金屬層殘留於基底表 面的厚度在500〜4000埃之間。接著，提供一第二研磨墊^ 再於第二研磨墊上進行一第二階段研磨，以完全去除開口 以外之銅金屬層。 依照本發明的較佳實施例所述的銅化學機械研磨方 法，上述之第一與第二階段研磨的研磨速率可以相同，或 疋弟一與苐二階段研磨的研磨速率是不同的。 本發明因為兩階段研磨步驟，所以可避免在化學機械 研磨方法後有銅金屬層缺漏的情形發生。此外，前述兩階 段=磨步驟可選擇在不同研磨墊上進行，因此更大大降低 因第階段研磨後殘留在研磨墊上的碎片而致使銅金屬層 表面發生缺漏的情形。 為讓本發明之上述和其他目的、特徵和優點能更明顯 易懂，下文特舉較佳實施例，並配合所附圖式，作詳細說 明如下。 【實施方式】 本發明之概念係在利用不同階段的研磨步驟，來降低 =至屬層發生缺漏的機率。因此，了面詳細描i^本發明之 fc例的貫關僅作為舉例之用，而非用以限定本發明之應 用範圍。 第一實施例 7 1274嫌 wf.doc/g 圖以至圖1D是利驗照本發明之第_實施例的銅化 學機械研磨方法對一金屬銅層進行平坦化之製程剖面示咅 圖。 请先芩照圖1A，本實施例是以一層銅金屬層11〇作為 待研磨層，且這一層銅金屬層11〇是覆蓋在具^如雙重金 屬鑲嵌開口的開口 102的基底1〇〇上並填滿開口 1〇2。其 中，在基底100與銅金屬層110之間可形成有一層阻障層 104,其材質例如是選自包括氮化鈦、鈦、組、氮化组與1 化鎢所組成之群組。而基底100通常可以包括晶圓、晶圓 上的各種半導體元件以及覆蓋半導體元件的介電層等，因 此於圖中不再詳細描繪。 之後，请麥照圖1B，進行一第一階段研磨，以去除銅 金屬層110的部分厚度，其中於第一階段研磨後，銅金屬 層110殘留於基底100表面的厚度τ例如是在5〇〇〜4〇〇〇 埃之間，、抑或根據銅金屬層11〇實際厚度及經驗法則選擇 適當的殘留厚度。此時，銅金屬㉟11〇表面會有較為嚴重 的缺漏現象，如圖中所標示的凹陷1 。 然後，請參照圖1C，進行—第二階段研磨，以完全去 除開口 102以外之銅金屬層110。在此同時，開口 1〇2以 ^阻障層刚也有可能被去除部分厚度，甚至是 去除。 此外，假使於開口 102内剩下的銅金屬層11〇a還可能 有夕數部位有缺漏現象，如圖lc中所標示的凹陷1〇8，則 可選擇參照圖1D，進行-第三階段研磨，以完全去除開口 8 127463〇0wf.d〇c/g 102以外的阻障層104，並持續研磨銅金屬層li〇a，以形 成如雙重金屬鑲嵌112之内連線。其中，第三階段研磨與 圖所不之第二階段研磨的研磨速率可以是不同的；或 者，第一與第二階段研磨均採取相同研磨速率，而將其合 併成同一個階段研磨步驟。再者，在本圖所示之階段 期間更可去除位於開口 102以外之阻障層102底下的部分 基底100。 " 第二實施例 圖2是依照本發明之第二實施例的銅化學機械研磨方 法之步驟流程圖，其係以第—實施例中覆蓋在具有開口的 基底上並填滿開口的銅金屬層作為待研磨層。 請麥照圖2，於步驟200中，提供一第一研磨墊，而 研磨墊的種類、材質均可依所需作變化。然後，於步驟21〇 中，於第一研磨墊上進行第一階段研磨，以去除銅金屬層 的部分厚度，且在此步驟後，銅金屬層殘留於基底表面的 厚度例如是在500〜4000埃之間，抑或根據銅金屬層實際 厚度及經驗法則選擇適當的殘留厚度。 、” 接著，於步驟220中，提供一第二研磨墊，其可以是 與第一研磨墊具有相同或不同的種類與材質，而兩者最大 差異是第一研磨墊已經進行過第一階段研磨，而第二研磨 墊則是沒用過的研磨墊或經調節過的研磨墊(⑺加出⑽以 polishing pad)，所以之後被研磨的銅金屬層表面將不會受 到第一階段研磨後殘留在第一研磨墊上的碎片破壞。θ ^ 者’不同的研磨墊可裝在不同的研磨台上。A general chemical mechanical polishing apparatus basically consists of a polishing table for performing wafer polishing, and a carrier for carrying the crystal 1: crystal. The polishing head will fix the lunar surface of the wafer, and then press the front side of the wafer on a polishing pad (on the table). When performing chemical mechanical polishing, the polishing table will rotate in a solid direction. 'And the grinding direction of the grinding is, for example, a linear 疋 and a grinding table-like--rotating in a fixed direction and the same angular velocity, and the grinding liquid is also added during the grinding (Slur, the surface is ground. 疋仃曰日月5 Rf.doc/g At present, when the Ultra Large Scde Integration is developed to a generation smaller than 〇·ΐ3μιη, in order to increase the execution speed of the wafer, it is necessary to effectively overcome the time delay caused by the impedance, etc. A material with a low dielectric constant and a metal copper are used as the interconnect structure. Therefore, the chemical mechanical polishing method for metallic copper is also in progress. However, the current copper chemical mechanical polishing method often has a grinding method. The problem of copper missing is urgently solved. SUMMARY OF THE INVENTION The object of the present invention is to provide a copper chemical mechanical polishing method which can be avoided in a chemical machine. There is a copper metal layer missing after the grinding method. Another object of the present invention is to provide a copper chemical mechanical polishing method, which can be carried out in different stages on different polishing pads to avoid copper after the chemical mechanical polishing method. The metal layer is missing. The present invention provides a copper chemical mechanical polishing method suitable for planarizing a copper metal layer covering a substrate having an opening and filling the opening. First, a first stage of grinding is performed to remove a portion of the thickness of the copper metal layer, wherein after the first stage of grinding, the thickness of the copper metal layer remaining on the surface of the substrate is between 500 and 4 angstroms. Two-stage grinding to completely remove the copper metal layer other than the opening. According to the copper chemical mechanical polishing method of the preferred embodiment of the present invention, the polishing rate of the above-mentioned first and second stage grinding may be the same, The polishing rates of the first and second stages of grinding are different. The present invention further provides a copper chemical mechanical polishing method suitable for planarization 6 : wf.d Oc/g a copper metal layer overlying a substrate having an opening and filling the opening. The method includes first providing a first polishing pad and then performing a first on the first polishing pad Stage grinding to remove a portion of the thickness of the copper metal layer, wherein after the first stage of grinding, the copper metal layer remains on the surface of the substrate to a thickness of between 500 and 4000 angstroms. Next, a second polishing pad is provided. Performing a second stage of polishing on the polishing pad to completely remove the copper metal layer other than the opening. According to the copper chemical mechanical polishing method of the preferred embodiment of the present invention, the polishing rate of the first and second stages of polishing may be the same. The grinding rate of the two-stage grinding is different from that of the second stage. The present invention avoids the occurrence of a copper metal layer missing after the chemical mechanical polishing method because of the two-stage grinding step. Further, the above two stages = the grinding step can be selected to be performed on different polishing pads, thereby greatly reducing the occurrence of a defect in the surface of the copper metal layer due to the debris remaining on the polishing pad after the first stage polishing. The above and other objects, features and advantages of the present invention will become more <RTIgt; [Embodiment] The concept of the present invention is to use different stages of the grinding step to reduce the probability of a defect in the subordinate layer. Therefore, the details of the fc examples of the present invention are intended to be illustrative only and not to limit the scope of application of the present invention. First Embodiment 7 1274 Wf.doc/g FIG. 1D is a cross-sectional view showing a process for flattening a metal copper layer by a copper chemical mechanical polishing method according to a first embodiment of the present invention. Referring first to FIG. 1A, in this embodiment, a layer of copper metal layer 11 is used as a layer to be polished, and this layer of copper metal layer 11 is covered on a substrate 1 having an opening 102 such as a double damascene opening. Fill the opening 1〇2. A barrier layer 104 may be formed between the substrate 100 and the copper metal layer 110, and the material thereof is, for example, selected from the group consisting of titanium nitride, titanium, a group, a nitride group, and a tungsten. The substrate 100 may generally include a wafer, various semiconductor elements on the wafer, and a dielectric layer covering the semiconductor element, etc., and thus will not be described in detail in the drawings. Thereafter, in accordance with FIG. 1B, a first stage of grinding is performed to remove a portion of the thickness of the copper metal layer 110, wherein after the first stage of polishing, the thickness τ of the copper metal layer 110 remaining on the surface of the substrate 100 is, for example, 5 〇. Between 〇4 〇〇〇 ,, or according to the actual thickness of the copper metal layer 11 及 and the rule of thumb to select the appropriate residual thickness. At this time, there will be a serious leak in the surface of the copper metal 3511, as shown by the recess 1 in the figure. Then, referring to Fig. 1C, a second stage of grinding is performed to completely remove the copper metal layer 110 other than the opening 102. At the same time, the opening 1〇2 is also likely to be removed from the thickness of the barrier layer, or even removed. In addition, if the remaining copper metal layer 11〇a in the opening 102 may have a missing portion at the vacant portion, as shown in FIG. 1c, the recess 1〇8 may be selected, and the third stage may be selected. Grinding to completely remove the barrier layer 104 other than the opening 8 127463 〇 0wf.d〇c/g 102, and continuously grinding the copper metal layer li〇a to form an interconnect such as the double damascene 112. Wherein, the polishing rate of the third stage grinding and the second stage grinding may be different; or both the first stage and the second stage grinding may take the same grinding rate and combine them into the same stage grinding step. Further, a portion of the substrate 100 underlying the barrier layer 102 outside the opening 102 can be removed during the stage shown in this figure. <Second Embodiment FIG. 2 is a flow chart showing the steps of a copper chemical mechanical polishing method according to a second embodiment of the present invention, which is a copper metal which is covered on a substrate having an opening and filled with an opening in the first embodiment. The layer acts as a layer to be polished. In the step 200, a first polishing pad is provided, and the type and material of the polishing pad can be changed as needed. Then, in step 21, the first stage of polishing is performed on the first polishing pad to remove a portion of the thickness of the copper metal layer, and after the step, the thickness of the copper metal layer remaining on the surface of the substrate is, for example, 500 to 4000 angstroms. Depending on the actual thickness of the copper metal layer and the rule of thumb, the appropriate residual thickness is chosen. Then, in step 220, a second polishing pad is provided, which may be the same or different kind and material as the first polishing pad, and the biggest difference between the two is that the first polishing pad has been subjected to the first stage grinding. The second polishing pad is an unused polishing pad or an adjusted polishing pad ((7) is added (10) to the polishing pad), so the surface of the copper metal layer to be polished afterwards will not be left after the first stage polishing. The debris on the first polishing pad is broken. θ ^ The different polishing pads can be mounted on different polishing tables.
接著，於步驟31〇中，於第 I2746i0twf.d〇c/g 之後，於步驟230中，於第二研磨墊上進行第二階段 研磨以元王去除開口以外的銅金屬層。此外，可參考第 一貫施例的圖1D，另外進行一道第三階段研磨，以去除開 口以外的阻障層，甚至是其下的基底。而這道選擇性增加 的第三階段研磨可以在一第三研磨墊上進行。 第三實施例 、圖3是依照本發明之第三實施例的銅化學機械研磨方 法之步驟流程@ m—實施例中覆蓋在具有開口的 基底上並填滿開U的銅金屬層作為待研磨層。 »明$圖3，於步驟300中，於第一研磨速率下進行 第一階段研磨’以去除銅金屬層的部分厚度，且在此步驟 後銅至屬層歹成留於基底表面的厚度例如是在5的〜4〇〇〇 埃=^卩或根軸金屬層實際厚度及經驗法騎擇適當 的歹义邊度。 --------研磨速率下進行第二階 又研磨’以完全去除開口以外的銅金屬層，其中第二階段 :磨可選擇繼續研磨’以去除開口以外的阻障層，更甚者 =磨掉其底下_的部分基底。此外，可參考第—實施例的 二D’另外進仃—道第三階段研磨，以絲 障層’甚至是其下的基底。 而於第三實施例中，可以在步驟3〇〇與31〇中分別使 用兩個研雜進行，甚至是用第三個研磨塾進行選擇性增 加的第三階段研磨。 第四實施例 127463(fiiwf.d〇c/g 圖4是依照本發明之第四實施例的銅化學機械研磨方 法之步驟流程圖，其係以第一實施例所述之銅金屬層作為 待研磨層。 請參照圖4，於步驟4〇〇中，於一研磨速率下進行第 階羊又研磨’以去除銅金屬層的部分厚度，且在此步驟後， 鋼金屬層殘留於基底表面的厚度例如是在500〜4000埃之 間，抑或根據銅金屬層實際厚度及經驗法則選擇適當的殘 g 留厚度。 接著，於步驟410中，於同一研磨速率下進行第二階 段研磨，以完全去除開口以外的銅金屬層，其中第二階段 研磨可選擇繼續研磨，以去除開口以外的阻障層，或持續 研磨掉其底下的部分基底。另外，如第一實施例的圖1〇 所示，本實施例可再進行一道第三階段研磨，以去除開口 以外的阻障層，甚至是其下的基底。 而於第四實施例中，可以在步驟400與410中分別使 用雨個研磨墊進行，甚至是用第三個研磨墊進行選擇性增 • 加的第三階段研磨。 — 曰 綜上所述，本發明之特點是藉由兩階段研磨步驟，所 避免在彳t學機^^研磨方法後有銅金屬層缺漏的情形發 生。此外，前述兩階段研磨步驟可選擇在不同研磨墊上^ 行，以更進一步降低因第一階段研磨後殘留在研磨墊上的 碎片而致使銅金屬層表面發生缺漏的情形。另外，兩階段 研磨步驟的製程參數還可作些變更，以便達到最佳研磨= I274〇a,doc/g 雖然本發明已以難實施·露如上，然其並非用以 二本發明，任何㈣此技#者，在*脫離本發明之精神 二靶圍内，當可作些許之更動與潤飾，因此本發明之保護 摩已圍當視後附之申請專利範圍所界定者為準。 又 【圖式簡單說明】 取圖1A至圖1D是利用依照本發明之第一實施例的銅化 本私;械研磨方法對一金屬銅層進行平坦化之製程剖面示意 • 圖。 圖2是依照本發明之第二實施例的銅化學機械研磨方 法之步驟流程圖。 圖3是依照本發明之第三實施例的銅化學機械研磨方 法之步驟流程圖。 圖4是依照本發明之第四實施例的銅化學機械研磨方 法之步驟流程圖。 【主要元件符號說明】 100 :基底 • 102 :開口 104 :阻障層 106、108 :凹陷 110、110a :銅金屬層 112 :雙重金屬鑲嵌 200〜230、300〜310、400〜410 :步驟 12Next, in step 31, after the second 2746i0twf.d〇c/g, in step 230, the second stage of polishing is performed on the second polishing pad to remove the copper metal layer other than the opening. In addition, reference may be made to Figure 1D of the first embodiment for a third stage of grinding to remove the barrier layer beyond the opening, or even the underlying substrate. This optional third stage grinding can be carried out on a third polishing pad. Third Embodiment, FIG. 3 is a flow chart of a copper chemical mechanical polishing method according to a third embodiment of the present invention. In the embodiment, a copper metal layer covering the substrate having an opening and filled with U is used as a to be ground. Floor. » Ming $ Fig. 3, in step 300, performing a first stage of grinding at a first polishing rate to remove a portion of the thickness of the copper metal layer, and after this step the copper to the layer is formed to a thickness remaining on the surface of the substrate, for example Is the actual thickness of the metal layer at 5 ~ 4 〇〇〇 = = ^ 卩 or root axis and the appropriate method to ride the appropriate margin. -------- Perform a second-order grinding at the grinding rate to completely remove the copper metal layer outside the opening, where the second stage: the grinding option can continue to grind 'to remove the barrier layer beyond the opening, even more = wear off part of the base underneath it. Further, the second stage of the first embodiment can be further referred to as the second layer of the first embodiment, with the wire barrier layer even the underlying substrate. In the third embodiment, it is possible to carry out the two-stage grinding in steps 3A and 31, respectively, even using the third grinding crucible for selective addition. Fourth Embodiment 127463 (fiiwf.d〇c/g FIG. 4 is a flow chart showing the steps of the copper chemical mechanical polishing method according to the fourth embodiment of the present invention, which is treated with the copper metal layer described in the first embodiment. Grinding layer. Referring to FIG. 4, in step 4, the first stage sheep is ground at a polishing rate to remove part of the thickness of the copper metal layer, and after this step, the steel metal layer remains on the surface of the substrate. The thickness is, for example, between 500 and 4000 angstroms, or the appropriate residual thickness is selected according to the actual thickness of the copper metal layer and the rule of thumb. Next, in step 410, the second stage of grinding is performed at the same polishing rate to completely remove a copper metal layer other than the opening, wherein the second stage grinding may optionally continue grinding to remove the barrier layer other than the opening, or continuously polish a portion of the underlying substrate. Further, as shown in FIG. 1A of the first embodiment, In this embodiment, a third stage grinding may be performed to remove the barrier layer other than the opening, or even the underlying substrate. In the fourth embodiment, the rain may be used in steps 400 and 410, respectively. The grinding pad is carried out, even with the third polishing pad for selective addition and addition of the third stage grinding. - In summary, the invention is characterized by a two-stage grinding step, which avoids the learning ^^The copper metal layer is missing after the grinding method. In addition, the above two-stage grinding step can be selected on different polishing pads to further reduce the copper metal remaining on the polishing pad after the first stage grinding. The surface of the layer is missing. In addition, the process parameters of the two-stage grinding step can be changed to achieve the best grinding = I274〇a, doc/g. Although the invention has been difficult to implement, the above is not used. In the case of the second invention, any (four) of the technology #, in the spirit of the second target of the invention, when some changes and retouching can be made, the protection of the present invention is attached to the scope of the patent application. The definition is based on the same. [FIG. 1A to FIG. 1D is a cross-sectional view showing the process of planarizing a metal copper layer by using the copper-polished method according to the first embodiment of the present invention; Figure 2 is a flow chart showing the steps of a copper chemical mechanical polishing method in accordance with a second embodiment of the present invention. Figure 3 is a flow chart showing the steps of a copper chemical mechanical polishing method in accordance with a third embodiment of the present invention. A flow chart of the steps of the copper chemical mechanical polishing method according to the fourth embodiment of the present invention. [Main element symbol description] 100: substrate • 102: opening 104: barrier layer 106, 108: recess 110, 110a: copper metal layer 112 : Double metal inlay 200~230, 300~310, 400~410: Step 12