1254381 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領域，丨3丄 ,, 貝竦特別是有關於一種以無電鍍 (咖她叫論财式在經還原之鋼金屬表面鍵上如^⑽或1254381 IX. Description of the invention: [Technical field to which the invention pertains] The present invention relates to the field of semiconductor manufacturing, 丨3丄, 竦, 竦 竦 竦 竦 竦 竦 竦 竦 竦 竦 竦 竦 竦 咖 咖 咖 咖 咖 咖 咖 咖 咖 咖 咖 咖 咖 咖 咖 咖The surface key is like ^(10) or
CoWB等含鈷阻障層的方法。 【先前技術】 • ^銅^屬導線在目前的積體電路元件製造中已逐漸取代傳統的 綠屬成為金屬内連線的主要材料規格，這是由於銅金屬具有較 =電阻料優點。目前，已有人提出以無電鍍方式在銅導線上 2沈積如CWP等含餘_或轉歸，獻賴導線完整 〇 i其巾’並_ CoWP巾_成分_改善銅轉特性。這種 阻障層-般是騎性地沈積麵完成研磨的暴觸金屬導線表面 上0 將這種阻障層選擇性地沈積在暴露出的銅金屬導線表面的方 法通常是_無電鍍技術，其包括將無電鑛溶液中的金屬離子以 化學方式退原並沈積在導體表面，而麵過程中並不需要從外界 提供任何㈣流。在實際應用上，_無魏技術可以利用沈浸 式無電鑛系統或者__式無電鍍系統來完成。若以沈浸式無 電，系統細’帶齡屬表面需浸泡在電解溶液巾，而若以喷灑 式無電鑛系紐行’則是將電液魏在舰物的表面。、 .1254381 、在將前述的含雜障層或阻障蓋層以無電鍍方式形成在銅金 屬上的過程t，銅金屬在環境中易氧化的特性即成為非常關鍵而 亟待解决的問題。不同於其他金屬晚化，銅金屬在低溫下(如· °c以下)容緒氧化成⑽及⑽，而且不會形成自我保護層來 避免被進v的氧化。不幸的是，前述含姑阻障層或阻障蓋層的 無電鑛製程對於銅金屬導線表面的潔淨度非常敏感。即使在^導 線表面存在少許魏化_會造成觀含雜障層姐障蓋層的 鲁 無電鍍製程的選擇性以及製程良率降低。 曰 在先刚技藝中’將銅導線表面上的氧化銅或污染物去除的方式 是將晶圓送至濕式清洗站，將晶圓浸泡在化學溶液中以溶解氧化 銅或污染物。然而’這樣的作法其缺點在於先前技藝中將晶圓浸 -泡在化學溶液中不一定能完全地將氧化銅或污染物清除乾淨，此 外，通常晶圓在濕式清洗站完成清洗後，不一定會馬上進行無電 鍍製私’而會有一段等待時間(Q_time)，此時，銅導線表面會產生 籲新的氧化銅’而影響後續無電鍍製程。 【發明内容】 本發明之主要目的在提供一種以無電鍍方式在經還原之銅金 屬表面鍍上如CoWP或CoWB等含鈷阻障層的方法，以解決 技藝的問題。 /N ° 根據本發明之較佳實施例，本發明坡露一種以無電鍍在基底上 1254381 形成金屬阻層的枝，包含扣下步驟： 在该基底上進行-鋼導線製 線，其具有一暴露出來的上表面；於雜底上形成至少—銅導 2該銅導_縣露_上表面進行預清洗製程； 表面= 過該爾洗軸魄解_該暴-麵上表面進行 表面接觸—活化溶液，俾進行—活化處理； 對_導線賴暴糾麵上表面在溫度低於娜C以下且人 及一乙_汽以及至少—觀的環境中進行—現翻火製程；以3 選^性地將該金屬轉蓋相無魏方式沈積在該銅導線的 β 亥暴路出來的上表面。 6為了使貴審查委員能更進一步了解本發明之特徵及技術内 谷，請參_下錢本發明之詳細說明與關。然而所附圖式僅 供參考與辅助說日，並_來對本個加以限制者。 【實施方式】 請翏閱第1圖至第4圖’其繪示的是銅金屬導線製程的剖面示 意圖。根#本㈣之健實酬，職料體树_導線的方 法是先在基底10上沈積如低介電常數材料等絕緣層12，然後於絕 緣層12中蝕刻出導線溝渠14，接著於導線溝渠14底部以及侧壁 上形成Ta/TaN等襯墊層16，然後再將導線溝渠14填滿如銅等導 電材料18，敢後，將導線溝渠14外多出來的襯墊層π以及導電 1254381 ====以咖，赚入絕 麵的做電常_射叹有_齡料數满，如 專’或者無機的低介電常數 吊數材枓，如HSQ專，而且不限定是多孔 牲二孔^的材料’此外，本發明之較佳實施例並不僅特別限 •、疋的低介電常數材料，前述賴緣層亦可以是般的介 # t材料，如二氧化矽或舰所構成。 如別所述，當銅金屬暴露在大氣環境下非常容易氧化形成氧化 銅/口此在進行疋化學機械研磨製程並形成銅導線之後，需再 進仃預/月洗製程’以去除諸如氧化物以及高分子殘留物等污染 物，接著就是進行銅導線表面的活化製程，通枝_含纪、 (palladium)等金屬做置彳嫌p_g)。在轉移到下一 2反應艙進行含_障層植障蓋層的無電鍍沈積之前，晶圓通 φ ^工^夕道程序的清潔以及活化等處理步驟，在晶圓的轉移過程 中’ 上暴露出的銅導線表面就可能接觸大氣而被氧化，因此， 控制㈣好的銅導線表面在錢中的停留時間即顯得非常關鍵。 : >閱第5圖’其繪示的是本發峨佳實施例的方法流程圖。 如第5圖所不，本發明方法係在完成前述銅導線製程(步驟51)中 的化學機械研磨製程之後，隨即進行晶圓以及銅導線表面的預清 洗(v驟52) ’接著，選擇性地進行銅導線表面活化製程(步驟幻）， 1254381 •然後’在含有乙醇蒸汽的環境下進行現場叫—叫處 理’將先前過活化_導線表面還原(步驟54)，隨即將剛剛還原 的銅導線表面接觸電解溶液，進行所謂的含钻阻障層或阻障蓋層 的無電鍍沈積製程(步驟55)，接下來，進行晶圓的後清洗製程(步 驟56)，最後進行晶圓的旋乾製程，將晶圓乾燥(步驟57)。 在前述的預清洗，也蚊步驟52巾，可將清洗溶液灑在晶圓 • 表面，通常可以利用pH值小於或等於4，例如pH值介於1 $至3 之間’的酸性溶液進行清洗，該清洗溶液可包含有整合劑(chdator) 或錯合劑(complexmg agent) ’例如羧酸(carboxylic acid)或者如檸檬 酸鹽(citrate)、草酸鹽(oxaiic acid)、甘胺酸(^㈣等羧酸鹽 (carboxylate)。例如，前述之清洗溶液可以包含有濃度〇 〇5 M至 〇.5 Μ的檬酉夂以及》辰度約0.25 Μ的曱基績酸(methanesulfonic acid) 〇 _ 在前述的銅導線表面活化製程，也就是步驟53中，其目的是 在沈積含始阻障層或阻障蓋層之前，先藉由置換鍍膜製程在暴露 出來的銅導線表面形成含有如把、銘、釕(mthenium)、锇(osmium)、 錢(rhodium)或銥(iridium)等催化金屬之初始層(initiation layer)。前 述的置換鍍膜製程通常是使用經稀釋的鈀鹽酸性溶液，例如氣化 纪(palladium chloride)、石肖酸把(palladium nitrate)或硫酸I巴 (palladium sulfate)等。舉例來說，這種置換鍍膜製程中使用的活化 溶液製備方法可以將約1毫升濃度為l〇wt%的硝酸鈀(pd(N03)2) 1254381 加入濃度10%的硝酸，再加去離子水到1公升。在另一個例子中， 活化溶液可含有約120ppm的氯化把以及足量的鹽酸，使其pH值 約介於1.5至3之間。通常將待活化的晶圓在室溫下浸泡在前述活 化溶液中約30秒左右。 在前述的含鈷阻障層或阻障蓋層的無電鍍沈積製程，也就是步 驟55中，所使用的鍍液組成可以包括濃度約介於5 mM到約20 mM的鈷金屬源、濃度約介於〇·ι mM到約5 mM的鎢金屬源、濃 度約介於5 mM到約50 mM的次填酸鹽(hypophosphite)、濃度約 介於5 mM到約50 mM的领烧還原劑(borane reductant)、濃度約介 於60 mM到約200 mM的檸檬酸鹽、濃度約介於50 mM到約150 mM的烧基胺(alkanolamine)、濃度約介於1 mM到約20 mM的删 酸、濃度約為50ppm的介面活性劑，以及pH值調整劑，將錢液 的pH值維持在約7至10之間。此外，前述的鍍液另可包括約 lOOppm 的穩定劑(stabilizer) 〇 請參閱第6圖，其緣示的是本發明較佳實施例中用以在乙醇蒸 汽環境中實施導電層表面的回火/還原設備示意圖。如第6圖所 示，回火/還原設備60包括石英反應艙62、加熱裝置64以及稀釋 乙醇蒸汽供應系統70，其中加熱裝置64可以是OTS加熱器或者 是加熱板。經過預清洗或者活化處理後的晶圓80被放置在石英反 應臉62中。石英反應艙62接有連接至稀釋乙醇蒸汽供應系統7〇 的氣體進口 66以及連接至排放管線的氣體出口 68。 1254381 $这的稀釋乙醇蒸以供應系統包括一起泡瓶，用 來提供乙醇蒸汽，以及載氣供應源73，用來提供氮氣或氦氣等載 氣。起泡瓶72連接至進氣口 721以及出氣口 722，而在容器723 中則承裝有乙醇724等醇類溶液。起泡瓶72的溫度建議控制在18 C，並以流量控制器(MFC)74控制經由進氣口 721吹入起泡瓶72 内的吹泡氮氣流4，而以流量控彻％控獅釋乙賴汽的氮氣 机里’其巾將稀槪氣流量控齡約為吹泡氮氣流量的三倍左右。 ’根據本發明之較佳實施例，在氣體進口 66端的稀釋乙醇蒸汽 的濃度約為1.25wt·%，而流量為a2_Q.8slm(standa識町沉 minute)。晶圓80的加熱溫度約介於丨⑻它至4〇〇〇c，較佳為i5〇 C至35G°C之間。在上述條件下，晶圓⑽在還原性的乙醇蒸汽環 境中回火約5分鐘左右。 、 此外，則述的回火/還原設備可以與無電鍍機台整合或内建，但 隹亦可以為單獨機台型態。若前述的回火續原設備與無電錢機台整 t或内建’前述的乙醇蒸汽回火步驟係在進行含雜障層或阻 障蓋層的無電鑛選擇沈積之前進行，然後立即現場進行含鉛阻障 層或阻障蓋層的無電錄選擇沈積。额述_火續原設備為單獨 機台，則前賴轉航回火步驟可以在銅表面活化之前或之後 進行皆可，或者也可以在預清洗步驟之前進行。 11 !254381 請專利範圍 【圖式簡單說明】 第1圖至第4圖繪示的是銅金屬導線製程的剖面示意圖。 第5圖繪示的是本發明較佳實施例的方法流程圖。 第6圖繪示的是本發明較佳實施例中用以在乙醇蒸汽環境中實 施導電層表面的回火/還原設備示意圖。 【主要元件符號說明】 10 基底 12 絕緣層 14 導線溝渠 16 襯墊層 18 導電材料 60 回火/還原設備 62 石英反應艙 64 加熱裝置 66 氣體進口 68 氣體出口 70 稀釋乙醇蒸汽供應系統 72 起泡瓶 73 載氣供應源 74 流量控制器 76 流量控制器 80 晶囫 721 進氣口 722 出氣口 723 容器 12A method of containing a cobalt barrier layer such as CoWB. [Prior Art] • The copper wire has gradually replaced the traditional green material as the main material specification for metal interconnects in the manufacture of current integrated circuit components. This is because copper metal has the advantage of being a resistive material. At present, it has been proposed to deposit a residual _ or a transition such as CWP on a copper wire by electroless plating, and to provide a complete wire 其 其 其 并 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ This barrier layer is generally a surface of the exposed metal wire that is ground by the riding surface. The method of selectively depositing the barrier layer on the exposed copper metal wire surface is usually _ electroless plating technology. It involves chemically deactivating metal ions in the electroless ore solution and depositing it on the surface of the conductor, while the surface process does not require any (four) flow from the outside. In practical applications, _Wei Wei technology can be completed by using an immersed electroless ore system or a __ type electroless plating system. If the immersive type is not used, the system should be immersed in the electrolytic solution towel on the surface of the age, and the electro-hydraulic system on the surface of the ship if it is sprayed. , .1254381, in the process of forming the aforementioned impurity-containing barrier layer or barrier cap layer on the copper metal by electroless plating, the characteristic that the copper metal is easily oxidized in the environment becomes a critical problem to be solved. Unlike other metal latening, copper metal is oxidized to (10) and (10) at low temperatures (eg, below °c), and does not form a self-protective layer to avoid oxidation by v. Unfortunately, the aforementioned electroless ore-free process with a barrier layer or a barrier cap is very sensitive to the cleanliness of the copper wire surface. Even if there is a little Weihua on the surface of the wire, it will cause the selectivity of the Lu non-electroplating process and the process yield reduction of the barrier layer containing the barrier layer.曰 In the first step, the method of removing copper oxide or contaminants from the surface of the copper wire is to send the wafer to a wet cleaning station to soak the wafer in a chemical solution to dissolve the copper oxide or contaminants. However, the disadvantage of such a method is that the immersion of the wafer in the chemical solution in the prior art does not necessarily completely remove the copper oxide or the contaminant. In addition, usually after the wafer is cleaned at the wet cleaning station, There will be a waiting time (Q_time) for the electroless plating process. At this time, the surface of the copper wire will generate new copper oxide, which will affect the subsequent electroless plating process. SUMMARY OF THE INVENTION A primary object of the present invention is to provide a method of plating a cobalt-containing barrier layer such as CoWP or CoWB on a surface of a reduced copper metal by electroless plating to solve the technical problem. /N ° According to a preferred embodiment of the present invention, the present invention discloses a branch for forming a metal resist layer by electroless plating on a substrate 1254531, comprising the step of deducting: performing a steel wire-forming line on the substrate, which has a The exposed upper surface; at least a copper-conducting layer is formed on the hetero-base. The copper-lead _ _ _ upper surface is pre-cleaned; surface = over-washed 魄 _ the violent surface surface contact - The activation solution is subjected to 活化-activation treatment; the surface of the _ wire ray is corrected in the environment below the temperature of N and below, and in the environment of the person and the _ _ steam and at least - the current turing process; The metal flip-chip is deposited in a Wei-free manner on the upper surface of the copper wire. 6 In order to enable your review board to further understand the features and technical aspects of the present invention, please refer to the detailed description and customs of the present invention. However, the drawings are for reference and assistance only, and are intended to limit the present. [Embodiment] Please refer to Figs. 1 to 4' for a schematic cross-sectional view of a copper metal wire process. The method of the health of the root (the fourth) is to deposit an insulating layer 12 such as a low dielectric constant material on the substrate 10, and then etch the wire trench 14 in the insulating layer 12, followed by the wire. A liner layer 16 such as Ta/TaN is formed on the bottom and side walls of the trench 14, and then the conductive trenches 14 are filled with a conductive material 18 such as copper. After the dare, the liner layer π and the conductive 1254381 are provided outside the conductor trenches 14. ====With coffee, earning a good job often _ sighs _ age material count full, such as special 'or inorganic low dielectric constant hang number material, such as HSQ special, and is not limited to porous Two-hole material 'In addition, the preferred embodiment of the present invention is not limited to the low dielectric constant material of the crucible, and the above-mentioned layer may also be a general material such as cerium oxide or a ship. Composition. As described above, when the copper metal is exposed to the atmosphere, it is very easy to oxidize to form copper oxide/mouth. After performing the chemical mechanical polishing process and forming the copper wire, it is necessary to carry out the pre-month/moon cleaning process to remove impurities such as oxides. And the pollutants such as polymer residues, followed by the activation process of the surface of the copper wire, and the metal such as palladium is p_g). Before the transfer to the next 2 reaction chamber for the electroless deposition of the barrier layer with the barrier layer, the wafer is exposed to the process of wafer transfer during the wafer transfer process. The surface of the copper wire that is exposed may be exposed to the atmosphere and oxidized. Therefore, it is very important to control the residence time of the (4) good copper wire surface in the money. : > Figure 5 is a flow chart of a method of the present invention. As shown in FIG. 5, the method of the present invention performs the pre-cleaning of the wafer and the surface of the copper wire immediately after completing the CMP process in the copper wire process (step 51) (v. 52). Ground copper wire surface activation process (step magic), 1254381 • Then 'on-site call-calling treatment in an environment containing ethanol vapor' will restore the previous over-activation_wire surface (step 54), and then just restore the copper wire The surface is contacted with the electrolytic solution, and a so-called electroless deposition process including a drill barrier layer or a barrier cap layer is performed (step 55). Next, a post-wafer cleaning process (step 56) is performed, and finally the wafer is spin-dried. The process is to dry the wafer (step 57). In the aforementioned pre-cleaning, also in the mosquito step 52, the cleaning solution can be sprinkled on the wafer surface, usually by using an acidic solution having a pH of less than or equal to 4, for example, a pH between 1 and 3'. The cleaning solution may comprise a chdator or a complexmg agent such as a carboxylic acid or a citrate, an oxaiic acid, a glycine (^(4) And a carboxylate. For example, the above-mentioned cleaning solution may contain a lemon having a concentration of 〇〇5 M to 〇.5 酉夂 and a methanesulfonic acid having a degree of about 0.25 Μ. The foregoing copper wire surface activation process, that is, in step 53, the purpose is to form a surface containing the exposed copper wire by a replacement coating process before depositing the initial barrier layer or the barrier cap layer. An initial layer of a catalytic metal such as mthenium, osmium, rhodium or iridium. The above-described displacement coating process usually uses a diluted palladium hydrochloric acid solution, such as gasification. Palladium chloride, Shi Xiao Palladium nitrate or palladium sulfate, etc. For example, the activation solution used in the displacement coating process can prepare about 1 ml of palladium nitrate (pd(N03) at a concentration of 10% by weight. 2) 1254381 Add 10% nitric acid and add deionized water to 1 liter. In another example, the activation solution may contain about 120 ppm of chlorination and a sufficient amount of hydrochloric acid to bring the pH to about 1.5 to Between 3, the wafer to be activated is usually immersed in the foregoing activation solution for about 30 seconds at room temperature. In the foregoing electroless deposition process containing a cobalt barrier layer or a barrier cap layer, that is, in step 55 The bath composition used may include a cobalt metal source having a concentration of about 5 mM to about 20 mM, a tungsten metal source having a concentration of about ι·1 mM to about 5 mM, and a concentration of about 5 mM to about 50 Å. mM hypophosphite, borane reductant at a concentration of from about 5 mM to about 50 mM, citrate at a concentration of from about 60 mM to about 200 mM, at a concentration of about 50 mM to about 150 mM of alkanolamine, acid concentration of about 1 mM to about 20 mM, The surfactant is about 50 ppm, and the pH adjuster maintains the pH of the liquid solution between about 7 and 10. In addition, the aforementioned plating solution may further comprise about 100 ppm of stabilizer. Figure 6 is a schematic illustration of a tempering/reducing apparatus for performing a surface of a conductive layer in an ethanol vapor environment in accordance with a preferred embodiment of the present invention. As shown in Fig. 6, the tempering/reducing apparatus 60 includes a quartz reaction chamber 62, a heating device 64, and a diluted ethanol vapor supply system 70, wherein the heating device 64 may be an OTS heater or a heating plate. The pre-cleaned or activated wafer 80 is placed in the quartz reaction face 62. The quartz reaction chamber 62 is connected to a gas inlet 66 connected to the diluted ethanol vapor supply system 7A and a gas outlet 68 connected to the discharge line. 1254381 $ This dilute ethanol is steamed to supply the system including a bubble flask for supplying ethanol vapor, and a carrier gas supply source 73 for supplying a carrier gas such as nitrogen or helium. The foaming bottle 72 is connected to the air inlet 721 and the air outlet 722, and the container 723 is filled with an alcohol solution such as ethanol 724. The temperature of the bubbling bottle 72 is recommended to be controlled at 18 C, and the flow controller (MFC) 74 controls the flow of the bubbling nitrogen gas 4 blown into the bubbling bottle 72 via the inlet port 721, and the flow control is controlled to the lion. In the nitrogen machine of Yi Lai's steam, the flow rate of the diluted helium gas is about three times that of the blowing nitrogen gas. According to a preferred embodiment of the present invention, the concentration of the diluted ethanol vapor at the gas inlet 66 end is about 1.25 wt.%, and the flow rate is a2_Q.8 slm (stand a minute). The heating temperature of the wafer 80 is approximately between 丨(8) and 4〇〇〇c, preferably between i5〇C and 35G°C. Under the above conditions, the wafer (10) is tempered in a reducing ethanol vapor atmosphere for about 5 minutes. In addition, the tempering/reduction equipment described may be integrated or built-in with an electroless plating machine, but the 隹 may also be a stand-alone type. If the aforementioned tempering and original equipment and the non-electricity machine are completed or built-in, the aforementioned ethanol vapor tempering step is performed before the electroless ore-selective deposition with the barrier layer or the barrier cap layer, and then immediately performed on site. Electrode-free selective deposition of lead-containing barrier layers or barrier cap layers. If the original equipment is a separate machine, the previous voyage tempering step can be performed before or after the copper surface is activated, or it can be performed before the pre-cleaning step. 11 !254381 Please patent range [Simple description of the drawings] Figures 1 to 4 show a schematic cross-sectional view of the copper metal wire process. Figure 5 is a flow chart showing the method of the preferred embodiment of the present invention. Figure 6 is a schematic illustration of a tempering/reducing apparatus for effecting the surface of a conductive layer in an ethanol vapor environment in accordance with a preferred embodiment of the present invention. [Main component symbol description] 10 Substrate 12 Insulation layer 14 Conductor trench 16 Liner layer 18 Conductive material 60 Tempering/reduction equipment 62 Quartz reaction chamber 64 Heating device 66 Gas inlet 68 Gas outlet 70 Dilution ethanol vapor supply system 72 Foaming bottle 73 Carrier gas supply 74 Flow controller 76 Flow controller 80 Crystal 721 Air inlet 722 Air outlet 723 Container 12