一種含氟清洗液Fluorine-containing cleaning solution
本發明涉及半導體元器件清洗液領域，尤其涉及一種含氟清洗液。The invention relates to the field of semiconductor component cleaning liquids, in particular to a fluorine-containing cleaning liquid.
在半導體裝置製造過程中，光阻層的塗敷、曝光和成像對裝置的圖案製造來說是必要的製程步驟。在圖案化的最後（即在光阻層的塗敷、成像、離子植入和蝕刻之後）進行下一製程步驟之前，光阻層材料的殘留物需徹底除去。在摻雜步驟中離子轟擊會硬化光阻層聚合物，因此使得光阻層變得不易溶解從而更難於除去。 目前，在半導體製造工業中一般使用兩步法（乾式灰化和濕蝕刻）除去這層光阻層膜。第一步利用乾式灰化除去光阻層（photo resist，PR）的大部分。第二步利用緩蝕劑組合物濕蝕刻/清洗製程除去剩餘的光阻層，其具體步驟一般為清洗液清洗/漂洗/去離子水漂洗。在此過程中，要求只除去殘留的聚合物光阻層和無機物，而不能攻擊損害金屬層。隨著半導體製造技術水準的提高以及電子裝置尺寸的降低，在半導體製造領域中使用金屬銅、low-k介質材料越來越多。尤其是銅雙大馬士革製程越來越廣泛的情況下，尋找能夠有效去除刻蝕殘留物的同時又能保護low-k介質材料、非金屬材料和金屬材料的清洗液就越來越重要。同時隨著半導體製程尺寸越來越小，清洗方式也越來越廣泛的使用到高速旋轉單片清洗，因此對金屬和非金屬材料的腐蝕控制也越來越嚴格，開發能夠適用於批量浸泡式、批量旋轉噴霧式清洗方式，尤其適用於高轉速單片旋轉式的清洗方式的清洗液是極待解決的問題。 現有技術中典型的清洗液有以下幾種：胺類清洗液，半水性胺基（非羥胺類）清洗液以及氟化物類清洗液。其中，前兩類清洗液主要應用在金屬鋁線的清洗製程中，該清洗液需要在高溫下清洗，一般在60℃到80℃之間，存在對金屬的腐蝕速率較大的問題。而現有的氟化物類清洗液雖然能在較低的溫度（室溫到50℃）下進行清洗，但仍然存在著各種各樣的缺點。例如，不能同時控制金屬和非金屬基材的腐蝕，清洗後容易造成通道特徵尺寸的改變，從而改變半導體結構；採用傳統苯並三氮唑作金屬銅的腐蝕抑制劑，雖然金屬銅的蝕刻速率較小，但是傳統唑類腐蝕抑制劑（BTA）不僅難以降解對生物體系不環保，而且在清洗結束後容易吸附在銅表面，導致積體電路的污染，會引起電路內不可預見的導電故障；有些現有技術避開傳統唑類使用能夠控制銅腐蝕和表面吸附的抑制劑，但是存在黏度表面張力大清洗效果不理想的問題。 US 6,387,859公開了含氟同時含有羥胺的清洗液，使用苯並三氮唑類（BTA）作為銅的腐蝕抑制劑，雖然保護效果較好，仍然未能解決表面吸附的問題，也沒有解決在高速旋轉下清洗液對金屬腐蝕在控制情況。US 5,972,862公開了含氟物質的清洗組合物，其包括含氟物質、無機或有機酸、季銨鹽和有機極性溶劑，pH為7～11，由於其清洗效果不是很穩定，存在多樣的問題。US 6,224,785公開了一種對銅有極低腐蝕的含氟清洗組合物，儘管該清洗液對銅的保護非常優良，不存在腐蝕抑制表面吸附問題，但是其清洗液的粘度與表面張力都很大，從而影響清洗效果，業界使用中也常常存在球形顆粒(ball defect)的問題。 因此，為了克服現有清洗液的缺陷，適應新的清洗要求，比如保護低介電材料、環境更為友善、克服金屬腐蝕抑制劑表面吸附、低缺陷水準、低刻蝕率以及適用於高轉速旋轉洗清方式等，極待尋求新的清洗液。In the fabrication of semiconductor devices, the application, exposure, and imaging of the photoresist layer are necessary process steps for pattern fabrication of the device. The residue of the photoresist layer material needs to be completely removed before the next process step is performed at the end of the patterning (i.e., after coating, imaging, ion implantation, and etching of the photoresist layer). Ion bombardment in the doping step hardens the photoresist polymer, thus making the photoresist layer less soluble and more difficult to remove. Currently, this layer of photoresist film is generally removed in a semiconductor manufacturing industry using a two-step process (dry ashing and wet etching). The first step uses dry ashing to remove most of the photo resist (PR). The second step utilizes a corrosion inhibitor composition wet etch/clean process to remove the remaining photoresist layer, the specific steps of which are typically rinse cleaning/rinsing/deionized water rinsing. In this process, it is required to remove only the residual polymer photoresist layer and the inorganic material, and not attack the damaged metal layer. With the improvement of the level of semiconductor manufacturing technology and the reduction of the size of electronic devices, more and more metal copper and low-k dielectric materials are used in the field of semiconductor manufacturing. Especially in the case of a wide range of copper double damascene processes, it is increasingly important to find a cleaning solution that can effectively remove etch residues while protecting low-k dielectric materials, non-metal materials and metal materials. At the same time, as the semiconductor process size becomes smaller and smaller, the cleaning method is more and more widely used for high-speed rotary single-chip cleaning. Therefore, the corrosion control of metal and non-metal materials is becoming more and more strict, and the development can be applied to batch immersion. The batch rotary spray cleaning method is especially suitable for the high-speed single-plate rotary cleaning method, which is an extremely problem to be solved. Typical cleaning fluids in the prior art are as follows: amine cleaning fluids, semi-aqueous amine based (non-hydroxylamine) cleaning fluids, and fluoride cleaning fluids. Among them, the first two types of cleaning liquid are mainly used in the cleaning process of the metal aluminum wire, and the cleaning liquid needs to be cleaned at a high temperature, generally between 60 ° C and 80 ° C, and there is a problem that the corrosion rate of the metal is large. While existing fluoride-based cleaning solutions can be cleaned at lower temperatures (room temperature to 50 ° C), there are still various disadvantages. For example, it is not possible to simultaneously control the corrosion of metal and non-metal substrates, and it is easy to cause changes in the channel characteristic size after cleaning, thereby changing the semiconductor structure; using conventional benzotriazole as a corrosion inhibitor of metallic copper, although the etching rate of metallic copper Smaller, but the traditional azole corrosion inhibitor (BTA) is not only difficult to degrade to the biological system is not environmentally friendly, and is easily adsorbed on the copper surface after cleaning, resulting in contamination of the integrated circuit, causing unpredictable conductive faults in the circuit; Some prior art techniques avoid the use of conventional azoles to control inhibitors of copper corrosion and surface adsorption, but have the problem of poor cleaning of the surface tension of the viscosity. US 6,387,859 discloses a cleaning solution containing fluorine and containing hydroxylamine, using benzotriazole (BTA) as a corrosion inhibitor of copper. Although the protective effect is good, the problem of surface adsorption is still not solved, and the problem is not solved at high speed. Rotating the cleaning fluid against metal corrosion in the control situation. No. 5,972,862 discloses a cleaning composition for a fluorine-containing substance comprising a fluorine-containing substance, an inorganic or organic acid, a quaternary ammonium salt and an organic polar solvent, having a pH of from 7 to 11, and which has various problems due to the fact that the cleaning effect is not very stable. US 6,224,785 discloses a fluorine-containing cleaning composition which has extremely low corrosion to copper. Although the cleaning solution is excellent in copper protection, there is no corrosion inhibiting surface adsorption problem, but the viscosity and surface tension of the cleaning liquid are large. Therefore, the cleaning effect is affected, and the problem of ball defects often occurs in the industry. Therefore, in order to overcome the defects of the existing cleaning solution, it is adapted to new cleaning requirements, such as protecting low dielectric materials, being more environmentally friendly, overcoming metal corrosion inhibitor surface adsorption, low defect level, low etching rate, and suitable for high-speed rotary washing. The cleaning method, etc., is extremely urgent to seek a new cleaning solution.
為解決上述問題，本發明提供一種不含有羥胺及氧化劑含氟清洗液，該清洗液清洗能力強，可有效去除半導體製程過程中等離子刻蝕殘留物，尤其是在銅馬士革製程中灰化後的殘留物，並且在高轉速單片機清洗中對非金屬材料（如氮氧化矽和低介質材料）和金屬材料（如Cu）等有較小的腐蝕速率。 具體地，本發明提供一種含氟清洗液，其特徵在於，含有以下組分及含量： a) 有機溶劑 10%～75%； b) 水 20%～60%； c) 氟化物 0.01%～25%； d) 有機胺 0.5%～15%； e) 肼及其衍生物 0.01%～10%，優選為0.05-5%。 優選地，所述溶劑包括亞碸、咪唑烷酮、吡咯烷酮、醯胺和醚中的一種或多種。 優選地，所述亞碸包括二甲基亞碸、二乙基亞碸和甲乙基亞碸中的一種或多種；所述咪唑烷酮包括2-咪唑烷酮、1,3-二甲基-2-咪唑烷酮和1,3-二乙基-2-咪唑烷酮中的一種或多種；所述吡咯烷酮包括N-甲基吡咯烷酮、N-乙基吡咯烷酮、N-環己基吡咯烷酮和N-羥乙基吡咯烷酮中的一種或多種；所述醚包括丙二醇單甲醚、丙二醇單乙醚、丙二醇單丁醚、二丙二醇單甲醚、二丙二醇單乙醚、二丙二醇單丁醚和三丙二醇單甲醚中的一種或多種。 優選地，所述氟化物包括氟化氫、和/或氟化氫與堿形成的鹽。其中，所述堿包括氨水、季胺氫氧化物和/或醇胺。 優選地，所述氟化物包括氟化氫（HF）、氟化銨（NH4
F）、氟化氫銨（NH4
HF2
）、四甲基氟化銨（N(CH3
)4
F）和三羥乙基氟化銨（N(CH2
OH)3
HF）中的一種或多種。 優選地，所述有機胺包括含羥基、氨基和羧基的有機胺中的一種或多種。所述有機胺的存在，有利於pH值穩定，提高清洗過程的穩定性和重現性。 優選地，所述含羥基的有機胺為醇胺；所述含氨基的有機胺為有機多胺；所述含羧基的有機胺為含氨基的有機酸。 優選地，所述有機胺包括乙醇胺、二乙醇胺、三乙醇胺、異丙醇胺、N，N-二甲基乙醇胺和N-甲基二乙醇胺，二乙烯三胺、五甲基二乙烯三胺和多乙烯多胺，2-氨基乙酸、2-氨基苯甲酸、亞氨基二乙酸，氨三乙酸和乙二胺四乙酸中的一種或多種。 更優選地，所述有機胺包括五甲基二乙烯三胺、亞氨基二乙酸和三乙醇胺中的一種或多種。 優選地，所述肼及其衍生物包括肼基甲酸甲酯、對肼基苯甲酸、肼基甲酸苄酯、肼基甲酸乙酯、肼基甲酸叔丁酯、硫酸肼、乙醯肼、甲醯肼、苯甲醯肼、草醯二肼、二甲醯肼、煙酸醯肼、碳酸二醯肼、苯磺醯肼、2-羥乙基肼、N-乙醯苯肼、對甲苯磺醯肼、鄰苯二甲醯肼、順丁烯二醯肼、4-羥基苯甲醯肼中的一種或多種。 有現有技術相比較，本發明的積極進步效果在於： 1）本發明所公開的含氟清洗液中不含有羥胺及氧化劑，其可有效去除半導體製程過程中等離子刻蝕的殘留物，尤其是在銅馬士革製程中灰化後的殘留物；並且在高轉速單片機清洗中對非金屬材料（如氮氧化矽和低介質材料）和金屬材料（如Cu）等有較小的腐蝕速率； 2）本發明所公開的含氟清洗液適用於批量浸泡式、批量旋轉噴霧式清洗方式，尤其適用於高轉速單片旋轉式的清洗方式，在高轉速單片清洗條件下，本發明的清洗液克服了傳統清洗液銅腐蝕抑制的缺陷； 3）另外，本發明提供的含氟清洗液可以在25℃至55℃下清洗等離子刻蝕殘留物，在半導體晶片清洗等微電子領域具有良好的應用前景。In order to solve the above problems, the present invention provides a fluorine-containing cleaning liquid containing no hydroxylamine and an oxidizing agent, and the cleaning liquid has strong cleaning ability, and can effectively remove medium ion etching residues in a semiconductor manufacturing process, especially after ashing in a copper-matrix process. Residues, and in high-speed single-chip cleaning, have a lower corrosion rate for non-metallic materials (such as niobium oxynitride and low dielectric materials) and metal materials (such as Cu). Specifically, the present invention provides a fluorine-containing cleaning liquid characterized by comprising the following components and contents: a) 10% to 75% of an organic solvent; b) 20% to 60% of water; c) 0.01% to 25% of fluoride d; organic amine 0.5% to 15%; e) hydrazine and its derivatives 0.01% to 10%, preferably 0.05-5%. Preferably, the solvent comprises one or more of an anthraquinone, an imidazolidinone, a pyrrolidone, a guanamine, and an ether. Preferably, the hydrazine includes one or more of dimethyl hydrazine, diethyl hydrazine, and methyl ethyl hydrazine; the imidazolidinone includes 2-imidazolidinone, 1,3-dimethyl- One or more of 2-imidazolidinone and 1,3-diethyl-2-imidazolidinone; the pyrrolidone includes N-methylpyrrolidone, N-ethylpyrrolidone, N-cyclohexylpyrrolidone, and N-hydroxyl One or more of ethyl pyrrolidone; the ether includes propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether and tripropylene glycol monomethyl ether. One or more. Preferably, the fluoride comprises hydrogen fluoride, and/or a salt formed by hydrogen fluoride and hydrazine. Wherein the hydrazine comprises ammonia water, quaternary ammonium hydroxide and/or alcohol amine. Preferably, the fluoride comprises hydrogen fluoride (HF), ammonium fluoride (NH 4 F), ammonium hydrogen fluoride (NH 4 HF 2 ), tetramethylammonium fluoride (N(CH 3 ) 4 F), and trishydroxyl One or more of ammonium fluoride (N(CH 2 OH) 3 HF). Preferably, the organic amine comprises one or more of an organic amine having a hydroxyl group, an amino group and a carboxyl group. The presence of the organic amine facilitates pH stability and improves the stability and reproducibility of the cleaning process. Preferably, the hydroxyl group-containing organic amine is an alcohol amine; the amino group-containing organic amine is an organic polyamine; and the carboxyl group-containing organic amine is an amino group-containing organic acid. Preferably, the organic amine comprises ethanolamine, diethanolamine, triethanolamine, isopropanolamine, N,N-dimethylethanolamine and N-methyldiethanolamine, diethylenetriamine, pentamethyldiethylenetriamine and One or more of polyethene polyamine, 2-aminoacetic acid, 2-aminobenzoic acid, iminodiacetic acid, aminotriacetic acid and ethylenediaminetetraacetic acid. More preferably, the organic amine includes one or more of pentamethyldiethylenetriamine, iminodiacetic acid, and triethanolamine. Preferably, the hydrazine and its derivatives include methyl carbazate, p-nonyl benzoic acid, benzyl carbazate, ethyl carbazate, tert-butyl carbazate, cesium sulfate, acetamidine, A Bismuth, benzamidine, valerian, dimethylhydrazine, bismuth nicotinate, bismuth carbonate, benzene sulfonium, 2-hydroxyethyl hydrazine, N-acetyl hydrazine, p-toluene One or more of hydrazine, phthalic acid, maleic acid, and 4-hydroxybenzhydrazide. Compared with the prior art, the positive progress of the present invention is as follows: 1) The fluorine-containing cleaning liquid disclosed in the present invention does not contain hydroxylamine and an oxidizing agent, and can effectively remove the residue of medium ion etching in the semiconductor manufacturing process, especially in Residues after ashing in the copper-mesh process; and in the high-speed single-chip cleaning, there is a small corrosion rate for non-metallic materials (such as bismuth oxynitride and low dielectric materials) and metal materials (such as Cu); 2) The disclosed fluorine-containing cleaning liquid is suitable for batch immersion type and batch rotary spray type cleaning method, and is especially suitable for high-speed single-piece rotary type cleaning method. The cleaning liquid of the invention overcomes the high-speed single-chip cleaning condition. The conventional cleaning solution copper corrosion inhibition defects; 3) In addition, the fluorine-containing cleaning liquid provided by the invention can clean the plasma etching residue at 25 ° C to 55 ° C, and has a good application prospect in the field of microelectronics such as semiconductor wafer cleaning.
本發明所用試劑及原料均市售可得。本發明的清洗液由上述成分簡單均勻混合即可制得。 表1實施例及對比例清洗液的組分和含量
效果實施例 為了考察該類清洗液在浸泡、低轉速(＜60rpmm/min）和高轉速(＞200rpm/min)下對金屬和非金屬材料的腐蝕情況，並進一步考察在單片高速旋轉清洗方式下對含有等離子刻蝕殘留物的金屬孔道的清洗情況，本發明採用了如下技術手段：即將金屬（Cu）空白矽片和非金屬（SiON和低介質（low-k）材料（BD））空白矽片分別浸入清洗液中，在40℃下以靜止或不同轉速浸泡30min，經去離子水漂洗後用高純氮氣吹乾。將大馬士革製程中含有等離子刻蝕殘留物的金屬孔道晶圓置於高速旋轉清洗方式下，在25℃至50℃下旋轉1.5min，經去離子水漂洗後用高純氮氣吹乾。殘留物的清洗效果及對金屬和非金屬的腐蝕情況如表2所示。 表2 部分實施例及對比例的腐蝕速率和清洗效果
從表2中可以看出：本發明的清洗液對半導體製成中所用的金屬（如Cu）和非金屬（SiON和BD）基本不會侵蝕，其腐蝕速率在浸泡、低轉速(＜60rpmm/min）和高轉速(＞200rpm/min)均接近或小於半導體業界通常在單片高速旋轉清洗下所要求的非金腐蝕速率＜2 Ǻ /min和金屬腐蝕速率＜5 Ǻ /min。 從對比例1和對比例2與實施例5和實施例12可以看出，使用半導體業界常用金屬腐蝕抑制劑BTA（苯並三唑）或者氮唑類腐蝕抑制劑，在浸泡、低轉速(＜60rpmm/min）下能夠抑制銅的腐蝕，但是在高轉速下不能控制銅的蝕刻速率，而本發明的清洗液在浸泡、低轉速(＜60rpmm/min）和高轉速(＞200rpm/min)都能夠控制金屬和非金屬的腐蝕速率，尤其是控制高速下的銅腐蝕問題。對比例3使用專利文獻CN101412949中公開的含氟清洗液，同樣發現，無法控制高轉速下的銅腐蝕問題。 進一步考察清洗液對等離子刻蝕殘留物進行清洗發現，其等離子刻蝕殘留物均被去除，而且高轉速下基本沒有腐蝕金屬和非金屬，大馬士革製程下銅的金屬孔道沒有變寬，使用常用的BTA和氮唑類腐蝕抑制劑的清洗液均出現了通道電性能測試不合格的問題，使用未加入肼及其衍生物公開過的含氟清洗液（CN101412949）出現了通道變寬的問題，進一步驗證了肼及其衍生物的加入在保證清洗效果的同時可以有效的控制金屬的腐蝕，同時在高速旋轉單片機清洗下仍然可以控制金屬銅的腐蝕速率。 應當理解的是，本發明中所提及的%，為質量百分比單位符號。 應當注意的是，本發明的實施例有較佳的實施性，且並非對本發明作任何形式的限制，任何熟悉該領域的技術人員可能利用上述揭示的技術內容變更或修飾為等同的有效實施例，但凡未脫離本發明技術方案的內容，依據本發明的技術實質對以上實施例所作的任何修改或等同變化及修飾，均仍屬於本發明技術方案的範圍內。The reagents and starting materials used in the present invention are commercially available. The cleaning liquid of the present invention can be obtained by simply and uniformly mixing the above components. Table 1 Example and Comparative Example of the composition and content of the cleaning solution Effect Example In order to investigate the corrosion of metal and non-metal materials in this type of cleaning solution under immersion, low rotation speed (<60rpmm/min) and high rotation speed (>200rpm/min), further study on single-piece high-speed rotary cleaning method In the case of cleaning metal vias containing plasma etch residues, the present invention employs the following technical means: blanks of metal (Cu) blanks and non-metals (SiON and low-k materials (BD)) The bracts were immersed in the cleaning solution, immersed at 40 ° C for 30 min at rest or at different speeds, rinsed with deionized water and then dried with high purity nitrogen. The metal channel wafer containing the plasma etching residue in the Damascene process was placed in a high-speed rotary cleaning mode, rotated at 25 ° C to 50 ° C for 1.5 min, rinsed with deionized water, and dried with high purity nitrogen. The cleaning effect of the residue and the corrosion of metals and non-metals are shown in Table 2. Table 2 Corrosion rate and cleaning effect of some examples and comparative examples It can be seen from Table 2 that the cleaning liquid of the present invention does not substantially erode the metals (such as Cu) and non-metals (SiON and BD) used in the manufacture of semiconductors, and the corrosion rate is in the soaking, low rotation speed (<60 rpmm/ Min) and high rotational speed (>200 rpm/min) are close to or less than the non-gold corrosion rate <2 Ǻ /min and metal corrosion rate <5 Ǻ /min required by the semiconductor industry under monolithic high-speed rotary cleaning. From Comparative Example 1 and Comparative Example 2 and Example 5 and Example 12, it can be seen that the metal corrosion inhibitor BTA (benzotriazole) or azole corrosion inhibitor is commonly used in the semiconductor industry, in soaking, low rotation speed (< Corrosion of copper can be suppressed at 60 rpmm/min), but the etching rate of copper cannot be controlled at high rotation speeds, while the cleaning solution of the present invention is in immersion, low rotation speed (<60 rpmm/min) and high rotation speed (>200 rpm/min). It is able to control the corrosion rate of metals and non-metals, especially the problem of copper corrosion at high speeds. Comparative Example 3 Using the fluorine-containing cleaning liquid disclosed in the patent document CN101412949, it was also found that the copper corrosion problem at high rotation speed could not be controlled. Further investigation of the cleaning solution to clean the plasma etching residue, the plasma etching residue is removed, and there is almost no corrosion of metal and non-metal at high speed, the metal hole of the copper in the Damascus process is not widened, the commonly used Both the cleaning solution of BTA and azole corrosion inhibitors have failed to pass the channel electrical performance test. The use of the fluorine-containing cleaning solution (CN101412949) which has not been added to the ruthenium and its derivatives has caused the problem of widening of the channel, and further It is verified that the addition of bismuth and its derivatives can effectively control the corrosion of the metal while ensuring the cleaning effect, and the corrosion rate of the metallic copper can still be controlled under the high-speed rotation of the single-chip cleaning. It should be understood that the % mentioned in the present invention is a mass percentage unit symbol. It should be noted that the embodiments of the present invention are preferred embodiments, and are not intended to limit the scope of the present invention. Any one skilled in the art may use the above-disclosed technical contents to change or modify the equivalent embodiments. Any modification or equivalent changes and modifications of the above embodiments in accordance with the technical spirit of the present invention are still within the scope of the technical solutions of the present invention.
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