1292359 九、發明說明： 【發明所屬之技術領域】 本發明係有關於半導體製程中之化學機械研磨(Chemical mechanical polishing，以下簡稱為CMP)領域，特別是有關於一種 新穎之研磨頭(carrier head)設計，可在研磨過程中獲得較佳的研磨 均勻度(uniformity)。 【先前技術】 在製作積體電路的過程中，不可避免地需要在一晶圓上沈積數 層不同材質的堆疊結構，如此一來，造成晶圓表面的不規則平面。 不規則的晶圓表面將導致一些黃光製程問題，例如聚焦深度(depth of focus ’ DOF)不足以及圖像轉移偏差。因此，在製作積體電路過 程中，便經常需要以平坦化技術，例如CMP技術，加以平坦化晶 圓的不規則表面。 CMP技術是將一待研磨晶圓面朝下壓於一研磨 pad)上，此待研磨晶圓係由一稱為研磨頭(can>ier hea(j)之圓盤狀機 構所固定，在研磨階段，研磨頭帶動此待研磨晶圓以—固定轉軸 旋轉’而研磨藝則以另一轉_走轉’然後藉由化學或機械方式得 以將晶圓表©待去除的介電層或金屬層研雜。目前較普遍的研 磨頭是一種稱為浮動(floating)研磨頭的設計，其係利用—彈性臈 (flexible membrane)將一晶圓支撐盤或背板(bcaking固定於二 基座下方，在研磨階段，可利用氣體加壓於晶圓支撐盤上， 1292359 以平均分散施於晶圓晶背的下壓力（do wnforce)。 習知的CMP製程常遇見的問題是形成晶圓待研磨面表面上的 圖案分佈以及高低落差往往並不平均，如此一來，造成在進行CMP 研磨時’晶圓表面上的研磨速率分佈上的不均勻，例如，在圖案 密度較高處的研磨速率較慢.，而在圖案密度較疏處則研磨較快。 此外，晶圓表面上的待研磨的材料層亦可能呈現一邊高一邊低的 φ 厚度不均現象，此時，習知的CMP製程以及傳統的研磨頭設計即 無法提供使晶圓表面有較佳平坦化的作用。 【發明内容】 本發明之主要目的在提供一種改良之研磨頭(carrierhead)設計 及化學^^研磨方法’可在CMP研磨過程中獲得較佳的研磨均勻度。 根據本發明之較佳實施例，本發明提供一種應用於化學機械研 響磨(CMP)製程之研磨頭，.包含有一殼體；一晶圓邊緣壓覆環，鎖固 於該殼體之-下方位置；-支撐背板，其具有複數個呈非同心圓 狀(non_concentric)排列的壓力區(pressure z〇ne)，且該支撐背板乓有 一晶圓接觸面以及一非晶圓接觸面，其中進行一 CMp研磨時，該 支撐背板的該晶圓接觸面係抵靠住一晶圓背面；以及一氣動裝 置，用來在進行該CMP研磨時獨立控制個別該複數個呈非同心圓 狀排列壓力區内施加在該晶圓背面的壓力。 Ϊ292359 根據本發明之触實補，本㈣提供—種化學機械研磨 方法，至少包含有以下之步驟： (a) 將一晶圓固定在一研磨頭上，其中該研磨頭包含有一壓力 裝置’其受一控制單元所控制’用來在進行-CMP研磨時，獨立 地控制施加在該晶圓㈣社，各辆傾狀制的壓力區 内，個別的壓力； (b) 分別使該研磨頭以及—研磨墊進行旋轉，纟中該研磨頭係 φ 放置在該研磨墊上； ' (C)提供一下壓力予該晶圓；以及 (d)將该晶圓上之一材料層均勻地研磨去除。 本發明之主要伽在於㈣於研糾，研_可藉由氣囊以及 背板底部的設計提供一即時可調整的下壓力，因此能夠改善晶圓 表面的研磨均勻度。 ★為了讓本發明之上述以及其它目的、特徵與優點能更明確易 懂’下文特舉-較佳實施例，配合所關示，作詳細說明。 【實施方式】 請參閱第1圖，其緣示的是本發明化學機械研磨機台之剖面示 意圖。如第1圖所示’本發明化學機械研磨機㈣包括有一研磨 頭52 ’用來固定一晶圓54。研磨頭52通常連接至一傳動轴以及 -機械轉換手臂(圖未示），其中機械轉換手臂可將晶圓在不同研磨 8 1292359 日日圓54係藉由晶圓邊緣壓覆環m限制並固定在研磨頭η 内日日圓邊緣壓覆環152 -般為環狀造㉟，可以螺絲鎖固於殼體 15〇周圍下方位置。曰曰曰圓邊緣壓覆環⑸於殼體15〇正下方定義出 一口袋區域(P〇cket area)，其大小恰好用來容納晶圓54。此外，晶 圓邊、、彖壓復％ 152的-内表面可以咬合晶jjj 54，以避免晶圓％ 在研磨期間從研磨頭52底部滑出。 曰曰月緩衝墊156係為一盤狀造型薄膜，可以為高分子材料所構 成，其位置在支撐背板154與晶圓54之間，可以壓力感應膠 (pressure sensitive adhesive)黏貼在支撐背板154上。晶背緩衝墊 156對於壓力較為敏感，可以緩衝施加於晶圓科背面的下壓力， 並可以補償背板154或晶圓背面的微小不平整表面。 此外，本發明研磨頭52另可包括一隔膜158，通常為一環狀撓 性材質膜(annular ring of a flexible material)，其一端係由殼體 150 以及aa圓邊緣壓覆環152所夾住，另一端則可以利用一箝制環 ((^11^1^啤)以螺絲鎖固在支撐背板154上方.。.隔膜158的組成可 以為橡膠或人造橡膠(elastomeric-coated fibric)，例如NYLON™或 N0MEX™，或者玻璃纖維等等。 支撐背板154可以是由不鏽鋼等較堅硬不易碎裂的材質所製成 的平坦圓盤，其大小可以較晶圓54稍微大一些。在進行CMP研 磨時，研磨頭52的下壓力係藉由支撐背板154施加於晶圓54的 1292359 背面’使下壓力以及研磨力道可以均勻的分散至·表面，藉此 達到均勻研磨的目的。支撐背板]54具有一晶圓接觸面以及_^非 晶圓接觸面，其巾進行CMP研糾，支射板154的晶圓接觸面 係抵靠住晶圓54的背面。 根據本發明之難實關，支射板154具有複數個呈非同心 圓狀(n〇n-c〇ncentric)排列的壓力區_贿e卻時分別由獨立的^ •間開口 162以及圍繞在中間開口周圍的開口 164所定義出來。支 撐背板154上所具有的複數個呈非同心圓狀排列之壓力區的數目 若大於5個則為較佳。 請參閱第3 @以及第4圖’其中第3 _示岐根據本發明較 佳實施例之支撐背板154的上視示意圖，第4圖緣示的是根據本 犛明另-較佳實施例之支射板154的上視示意圖。如第3圖所 不’在支撐背板154共計形成6個非同心圓狀之壓力區，其中中 間開口⑹由周圍的開口 164所包圍。中間開口 162為—圓形開 口，而周圍開口 164則為扇形開口。 如第4 II所不，根據本發明之另—較佳實施例，在支撐背板⑼ 共計形成9個非同心圓狀之壓力區，其中中關口 162同樣由周 圍的開口⑹所包圍，而中間開口 162為一正城矩形開口，而 周圍開π 164則為不規則開口。此外，形成在支撐背板154上的 —開口設計’其數目可以超過9個以上，熟f該項技藝者應理解在 1292359 第3圖以及第4圖中的開口圖案以及分佈僅為例示。 如第2圖所示，根據本發明之較佳實施例，本發明研磨頭52 另可包括有複數個充氣氣囊裝置(pneumatic bladder) 182及184，其 分別容置於支撐背板154上相對應的中間開口 162以及周圍開口 164内，用來獨立地控制個別壓力區中施加在晶圓54背面的下壓 力。上述複數個充氣氣囊裝置182及184的充氣以及抽氣可藉由 φ 連接至氣體源或泵浦的個別氣體供應管路來完成。 請參閱第5圖，其繪示的是本發明另一較佳實施例的研磨頭剖 面結構示意圖。如第5圖所示，本發明另一較佳實施例的研磨頭 52與第2圖所示的研磨頭不同之處在於，另外在各個非同心圓狀 壓力區内分別設置有壓力感應元件192及194，其中壓力感應元件 192係e又置在中間開口 162内，而壓力感應元件係設置在周圍 ▲ 開口 164内。 根據本發明讀佳實侧，壓力顧元件192及194可以是壓 電材料、壓電結晶、壓電感應器或壓電陶賴應器等，例如，鈦 酸鋇(BalXB)、AIN、ZnO、鈦酸錯錯(PZT)、氧化錯、氧化鈕 (Ta205)组g文鹽、石英、電氣石、羅德鹽、銳酸鹽等。 本么月之另一主要特徵在於壓力感應元件192及194可以在 CMP；^磨過&中彳貞測晶圓表面由於高低起伏所產生的壓力變化， 1292359 % 並且能夠將訊號傳送回CMP機台的控制單元，例如電腦，控制單 凡在根據壓力感應元件192及〗94所回饋㈣號即時地控 j氣體源的輸出至上述複數個充氣氣囊裝置182及184的壓力， 藉此改變非同心圓狀壓力區内的下壓力，如此使得晶圓的研磨可 以精準地受到㈣，並改#研磨均皱，並且相賴不同的晶 圓表面輪廓皆可得到較佳的平坦性。 • 以上所述僅為本發明之較佳實施例，凡依本發明申請專利範圍 所做之均等變化與修飾，皆應屬本發明之涵蓋範圍。 【圖式簡單說明】 第1圖綠示的是本發明化學機械研慶機台之剖面示意圖。 第2圖、、、a示的疋本發明較佳實施例之研磨頭的剖面結構示意圖。 第3圖繪示的是本發明較佳實施例之支撐背板的上視示意圖。 帛4圖知的是本發明另_較佳實麵支撐背板的上視示意圖。 第5圖繪不的是本發明另一較佳實施例研磨頭剖面結構示意圖。 【主要元件符號說明】 50 化學機械研磨機台 52 研磨頭 54 晶圓 56 研磨墊 58 研磨平台 60 轉軸 62 轉軸 150 殼體 152 晶圓邊緣壓覆環 154 支撐背板 1-292359 156 晶背緩衝墊 158 隔膜 162 中間開口 164 周圍開口 182 充氣氣囊裝置 184 充氣氣囊裝置 192 壓力感應元件 194 壓力感應元件 § 141292359 IX. Description of the Invention: [Technical Field] The present invention relates to the field of chemical mechanical polishing (hereinafter referred to as CMP) in a semiconductor process, and more particularly to a novel carrier head Designed to achieve better uniformity during the grinding process. [Prior Art] In the process of fabricating an integrated circuit, it is inevitable to deposit a plurality of stacked structures of different materials on a wafer, thus causing irregularities in the surface of the wafer. Irregular wafer surfaces will cause some yellow light process problems, such as insufficient depth of focus (DOF) and image transfer deviation. Therefore, in the process of fabricating an integrated circuit, it is often necessary to planarize the irregular surface of the crystal by a planarization technique such as CMP technique. The CMP technique is to press a wafer to be polished face down on a polishing pad, and the wafer to be polished is fixed by a disk-shaped mechanism called a polishing head (can>ier hea(j). In the stage, the polishing head drives the wafer to be ground to rotate with a fixed axis, while the grinding process rotates with another rotation, and then chemically or mechanically removes the dielectric layer or metal layer to be removed. Currently, the more common grinding head is a design called floating grinding head, which uses a flexible membrane to fix a wafer support disc or backing plate (bcaking under the two bases). In the grinding stage, gas can be pressed onto the wafer support disk, 1292359 to evenly distribute the lower pressure applied to the wafer back. The conventional CMP process often encounters the problem of forming a wafer to be polished. The pattern distribution on the surface and the height difference are often not uniform, thus causing unevenness in the distribution of the polishing rate on the wafer surface during CMP polishing, for example, the polishing rate is slower at higher pattern density. In the pattern density In the case of a thinner surface, the polishing is faster. In addition, the layer of material to be polished on the surface of the wafer may exhibit a φ thickness unevenness on one side and a low side. In this case, the conventional CMP process and the conventional polishing head design cannot Providing a function of better planarizing the surface of the wafer. SUMMARY OF THE INVENTION The main object of the present invention is to provide an improved carrier head design and chemical polishing method which can be preferably obtained in a CMP polishing process. Polishing uniformity. According to a preferred embodiment of the present invention, the present invention provides a polishing head for use in a chemical mechanical grinding (CMP) process, comprising a housing; a wafer edge pressing ring, locked to the a lower-side position of the housing; a support backing plate having a plurality of pressure zones in a non-concentric arrangement, and the support backplane has a wafer contact surface and an amorphous a circular contact surface, wherein, when performing a CMp polishing, the wafer contact surface of the support backplane is abutted against a back surface of a wafer; and a pneumatic device for independently controlling the plurality of individual ones during the CMP polishing The pressure applied to the back surface of the wafer in a pressure zone is arranged non-concentrically. Ϊ 292359 According to the touch compensation of the present invention, (4) provides a chemical mechanical polishing method comprising at least the following steps: (a) a crystal The circle is fixed on a polishing head, wherein the polishing head comprises a pressure device 'which is controlled by a control unit' for independently controlling the application to the wafer (4) during the -CMP polishing process. In the pressure zone, individual pressures; (b) respectively rotating the polishing head and the polishing pad, wherein the polishing head system φ is placed on the polishing pad; '(C) providing a pressure to the wafer; and d) uniformly polishing one of the material layers on the wafer. The main gamma of the present invention is that (4) the research and correction can provide an instantaneous adjustable downforce by the design of the airbag and the bottom of the backboard, thereby improving the uniformity of the grinding of the wafer surface. The above and other objects, features and advantages of the present invention will become more <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; [Embodiment] Referring to Figure 1, there is shown a cross-sectional view of a chemical mechanical polishing machine of the present invention. As shown in Fig. 1, the chemical mechanical polishing machine (4) of the present invention comprises a polishing head 52' for fixing a wafer 54. The polishing head 52 is typically coupled to a drive shaft and a mechanical shifting arm (not shown), wherein the mechanical shift arm can limit and secure the wafer at different grinding times by a wafer edge crimping ring m at different lengths of 1,292,359,359 yen. The inner circumference of the grinding head η, the edge-rimming ring 152, is generally formed in an annular shape 35, and can be screwed to a position below the casing 15〇. The rounded edge crimp ring (5) defines a pocket area directly below the housing 15 that is sized to receive the wafer 54. In addition, the inner side of the rounded edge, 彖 复 152 may bite the crystal jjj 54 to prevent the wafer % from slipping out of the bottom of the polishing head 52 during grinding. The moon cushion 156 is a disc-shaped molding film, which can be composed of a polymer material, and is disposed between the supporting back plate 154 and the wafer 54 and can be adhered to the supporting back plate by a pressure sensitive adhesive. 154. The crystal back cushion 156 is sensitive to pressure and can cushion the downforce applied to the back side of the wafer family and compensate for the small uneven surface of the back sheet 154 or the back side of the wafer. In addition, the polishing head 52 of the present invention may further include a diaphragm 158, which is generally an annular ring of a flexible material, one end of which is clamped by the housing 150 and the aa round edge pressing ring 152. At the other end, a clamp ring ((^11^1^ beer) can be screwed onto the support backing plate 154. The diaphragm 158 can be made of rubber or elastomer (elastomeric-coated fibric), such as NYLON. TM or NOMEXTM, or fiberglass, etc. The support backing plate 154 may be a flat disc made of a harder and less fragile material such as stainless steel, which may be slightly larger in size than the wafer 54. When the downward pressure of the polishing head 52 is applied to the back surface of the 1292359 of the wafer 54 by the support backing plate 154, the downward pressure and the grinding force can be uniformly dispersed to the surface, thereby achieving uniform polishing. Supporting the backing plate] 54 has a wafer contact surface and a non-wafer contact surface, and the towel is subjected to CMP research, and the wafer contact surface of the branch plate 154 abuts against the back surface of the wafer 54. According to the present invention, The branch plate 154 has a plurality of non-representations The pressure zone _ bribes are defined by separate openings 162 and openings 164 around the intermediate opening. The plurality of support backing plates 154 Preferably, the number of pressure zones arranged in a non-concentric arrangement is greater than 5. Please refer to FIG. 3 @ and FIG. 4 'where the third embodiment of the supporting back plate 154 according to the preferred embodiment of the present invention. The top view shows a top view of the support plate 154 according to another preferred embodiment of the present invention. As shown in Fig. 3, a total of six non-concentric circles are formed on the support back plate 154. a pressure zone in which the intermediate opening (6) is surrounded by a peripheral opening 164. The intermediate opening 162 is a circular opening and the peripheral opening 164 is a fan-shaped opening. As in Section 4 II, another preferred embodiment of the present invention In the embodiment, a total of nine non-concentric pressure zones are formed in the support backing plate (9), wherein the middle gateway 162 is also surrounded by the surrounding opening (6), and the intermediate opening 162 is a rectangular opening of the city, and the circumference is π 164. Irregular opening. In addition, formed in the branch The number of openings in the backing plate 154 may be more than 9 or more. It should be understood by those skilled in the art that the opening patterns and distributions in the 1292 and 4 figures are only exemplified. In accordance with a preferred embodiment of the present invention, the polishing head 52 of the present invention may further include a plurality of pneumatic bladders 182 and 184 that are respectively received in and around the corresponding intermediate opening 162 on the support backing plate 154. Within opening 164 is used to independently control the downforce applied to the back side of wafer 54 in the individual pressure zones. The aeration and evacuation of the plurality of inflatable airbag devices 182 and 184 described above can be accomplished by connecting φ to a gas source or pumping individual gas supply lines. Referring to Figure 5, there is shown a cross-sectional view of a polishing head according to another preferred embodiment of the present invention. As shown in Fig. 5, the polishing head 52 of another preferred embodiment of the present invention is different from the polishing head shown in Fig. 2 in that pressure sensing elements 192 are additionally provided in each of the non-concentric circular pressure zones. And 194, wherein the pressure sensing element 192 is further disposed in the intermediate opening 162, and the pressure sensing element is disposed in the surrounding ▲ opening 164. According to the reading of the preferred side of the present invention, the pressure elements 192 and 194 may be piezoelectric materials, piezoelectric crystals, piezoelectric inductors or piezoelectric ceramics, etc., for example, barium titanate (BalXB), AIN, ZnO, Titanic acid error (PZT), oxidation error, oxidation button (Ta205) group g salt, quartz, tourmaline, Rhodes salt, sharp acid salt and the like. Another major feature of this month is that the pressure sensing elements 192 and 194 can detect the pressure change of the wafer surface due to the high and low fluctuations in the CMP; 1292359% and can transmit the signal back to the CMP machine. The control unit of the station, such as a computer, controls the pressure of the output of the gas source to the plurality of inflatable airbag devices 182 and 184 in real time according to the feedback (4) of the pressure sensing elements 192 and 94, thereby changing the non-concentricity. The downforce in the circular pressure zone, so that the grinding of the wafer can be accurately received (4), and the grinding is uniform, and the flatness of the wafer surface contour can be better. The above is only the preferred embodiment of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view showing the chemical mechanical polishing machine of the present invention. 2, and a are schematic cross-sectional views of a polishing head according to a preferred embodiment of the present invention. FIG. 3 is a top plan view showing a supporting backing plate according to a preferred embodiment of the present invention. Figure 4 is a schematic top view of another preferred solid support backing plate of the present invention. Figure 5 is a schematic cross-sectional view showing a polishing head according to another preferred embodiment of the present invention. [Main component symbol description] 50 Chemical mechanical polishing machine 52 Grinding head 54 Wafer 56 Grinding pad 58 Grinding platform 60 Rotary shaft 62 Rotary shaft 150 Housing 152 Wafer edge pressing ring 154 Supporting back plate 1-292359 156 Crystal back cushion 158 diaphragm 162 intermediate opening 164 peripheral opening 182 inflatable airbag device 184 inflatable airbag device 192 pressure sensing element 194 pressure sensing element § 14