络合剂对铜CMP去除速率及机理的研究

利用电化学和化学机械抛光(CMP)实验方法研究了抛光液添加成分甘氨酸、L-精氨酸与酒石酸钾三种络合剂对铜CMP过程的界面电化学腐蚀作用及去除速率影响。采用原子力显微镜(AFM)和扫描电子显微镜(SEM)表征了铜与含有络合剂的碱性溶液产生界面化学腐蚀的表面微观形貌。结果表明,Cu表面腐蚀电流均大幅增强,揭示了三种络合剂均促进了铜氧化产物的化学络合溶解。CMP的实验结果表明,添加三种络合剂的抛光液对铜CMP的去除速率为甘氨酸>L-精氨酸>酒石酸钾。综合Cu CMP去除速率与表面形貌对比分析,L-精氨酸的络合能力与对铜表面的纳米形貌腐蚀协同性更强,获得了CMP去除速率促进下的Cu低表面微粗糙度。     

胍离子对铜化学机械抛光的影响

对铜晶圆进行化学机械抛光(CMP),溶液组成和工艺条件为:胶体二氧化硅(平均粒径85 nm)5%(质量分数),30%H_2O_2 5 mL/L,胍离子(Gnd+,由碳酸胍GC或盐酸胍GC提供)适量,抛光压力5.2 kPa,抛头转速87 r/min,抛光盘转速93 r/min,抛光液体积流速300 mL/min,时间1 min。研究了抛光液中Gnd~+浓度对铜去除速率的影响,通过电化学方法及X射线光电子能谱分析了Gnd~+在铜表面的作用机制,探讨了Gnd~+对铜CMP后表面粗糙度的影响机制。一方面,随抛光液中GC浓度的升高,铜的去除速率增大,GC浓度为80 mmol/L时满足去除速率高于200 nm/min的要求;另一方面,Gnd+的引入不仅加剧了铜晶圆表面的化学腐蚀,而且使抛光液在铜晶圆表面的接触角增大,铜晶圆抛光后表面粗糙度增大。     

BTA与表面活性剂O-20复配对铜CMP缓蚀行为的研究

通过电化学和化学机械抛光实验,研究了铜互连CMP中低浓度缓蚀剂BTA和非离子表面活性剂O-20复配对Cu电化学腐蚀及去除速率的影响,同时利用扫描电子显微镜(SEM)和原子力显微镜(AFM)表征了Cu表面形貌。电化学实验结果表明,在双氧水、甘氨酸体系下,0.5 mmol/L BTA与0.5 mmol/L O-20复配后,Cu表面腐蚀减少,其缓蚀效率动态条件下为59.58%,静态条件下为85.36%,相当于1mmol/L BTA的缓蚀效率。CMP实验结果表明,BTA与O-20复配后,Cu的去除速率为113 nm/min,表面微粗糙度降低,可达0.953 nm。使用低浓度BTA与O-20复配能抑制Cu表面腐蚀,降低Cu表面抛光后的微粗糙度,并且有利于CMP后清洗。     

抛光液组分对3D微同轴中铜和光刻胶化学机械抛光速率选择性的影响

研究了碱性抛光液的pH、SiO₂磨料质量分数、H₂O₂体积分数和甘氨酸质量分数对3D微同轴加工中铜和光刻胶化学机械抛光(CMP)去除速率的影响,得到较佳的抛光液组成为：SiO₂ 5%,H₂O₂ 20 mL/L,甘氨酸2.5%,pH=10。采用该抛光液时,铜和光刻胶的去除速率非常接近,满足3D微同轴加工对铜和光刻胶CMP去除速率选择性的要求。     

铜在5%过氧化氢消毒剂溶液中的腐蚀行为

新冠疫情期间双氧水(H₂O₂)等氧化型消毒剂的大量使用容易使金属构件产生腐蚀。采用电化学阻抗谱(EIS)、极化曲线、弛豫时间分布法(DRT)和微观形貌表征等方法对铜材料在5%过氧化氢消毒剂溶液中的腐蚀行为进行了研究。结果表明：在过氧化氢溶液中，铜表面呈现全面腐蚀的特征，不会出现腐蚀坑等局部腐蚀的现象。阴极还原过程是H₂O₂消毒剂溶液中铜腐蚀反应的控制步骤。阴极Tafel斜率随温度的升高而增大，腐蚀速率随着增加。腐蚀反应过程中，O₂扩散过程的弛豫时间更长，说明O₂扩散过程是过氧化氢腐蚀反应的重要控制步骤。研究结果有望增加大众对新冠防疫措施下的双氧水消毒剂腐蚀金属构件的认知。     

大气环境下A3钢腐蚀现象的研究

采用三电极体系研究了液滴浓度以及环境相对湿度对液滴下镀锌钢腐蚀的影响,采用电化学交流阻抗和电化学噪声等对腐蚀的发展过程进行测试。结果表明,在Na Cl浓度为1.5%时腐蚀速率较小;当Na Cl浓度小于1.5%时,随着浓度的减小腐蚀速率增大;当Na Cl浓度大于1.5%时,随着浓度的增加腐蚀速率增大。在环境湿度为80%RH时腐蚀速率最小,湿度低于80%RH时,随湿度增加腐蚀速率减小;在湿度高于80%RH时,随着湿度的增加,腐蚀速率增大。     

以甘氨酸为代表的氨基酸类化学添加剂在CMP工艺中的应用研究

首先介绍了甘氨酸的基本性质,接着回顾了近年来国内外甘氨酸在集成电路多层布线及其它材料CMP中的不同应用,归纳总结表明甘氨酸在CMP过程中可以起到络合、缓蚀、控制电偶腐蚀、催化等多种作用,具有宽泛的应用领域,最后对氨基酸类的添加剂在CMP中的应用前景进行了展望。     

纳米SiO2浆料中半导体硅片的化学机械抛光速率及抛光机理

采用电化学方法,研究了SiO2浆料pH值、H2O2浓度、固体含量以及抛光转速、压力和时间等不同抛光工艺参数对n型半导体单晶硅片(100)和(111)晶面化学机械抛光(chemical mechanical polishing,CMP)去除速率的影响和作用机理.结果表明:抛光速率随SiO2固体含量、抛光转速及压力的增加而增大,随抛光时间的增加而减小;在pH值为10.5和H2O2为1%(体积分数)时,抛光速率出现最大值;相同抛光工艺条件下(100)晶面的抛光速率远大于(111)晶面.半导体硅片CMP过程是按照成膜(化学腐蚀作用)→去膜(机械磨削作用)→再成膜→再去膜的方式进行,直到最终全局平坦化.实验所获得适合n型半导体硅片CMP的优化工艺参数为:5%～10% SiO2(质量分数),pH=10.5,1%H2O2,压力为40 kPa及(110)晶面和(111)晶面的抛光转速分别为100 r/min和200 r/min;在该条件下10% SiO2浆料中抛光30 min得到的抛光硅片的表面粗糙度为0.7 nm左右.     

氨碱性蚀刻液中铜溶解过程的化学动力学

氨碱性溶液是印制电路板工业中采用最为广泛的蚀刻溶液,但是关于溶液中铜溶解过程的动力学研究还比较缺乏。研究利用模拟实验的方法,定量地研究了铜溶解反应的化学动力学性质。当速度梯度G值大于7 570 s~(-1)时,铜溶解速率不受混合强度影响的传质速率限制;在反应前120 s内,平均单位面积铜溶解质量与反应时间呈线性关系,反应的速率常数约为0.137 3 mg/(cm~2·s);溶液Cu~(2+)浓度低于0.8 mol/L时,铜溶解速率随Cu~(2+)浓度增大而线性增大,此区间反应符合一级反应动力学;Cu~(2+)浓度约为1.0 mol/L时溶解速率最大;温度对反应速率的影响非常显著,升高温度反应速率增加较快,50℃时溶解速率可达21.106μm·L/(min·mol);溶解反应的Arrhenius活化能Ea约为23.7 k J,频率因子A约为1.43×10~5。     

铜基片静态气液界面腐蚀规律的实验

气液两相界面腐蚀广泛存在于日常工业中。因气液相界面存在不稳定特性,迄今对于相界面处腐蚀的研究多针对不断变化的界面位置附近,分析一段时间内的累积腐蚀效果。本文向液相内注入一定体积的气泡,维持气液界面在金属铜壁面的稳定以及气液相界面和液相主体浓度近似恒定;在含不同Cl^-浓度的溶液中,通过电化学方法对比有无相界面的腐蚀规律,并根据数据深入分析相界面处的腐蚀机理。结果表明：引入气液界面导致铜试样腐蚀电位升高、腐蚀电流增大,腐蚀更严重;气液界面处由于引入微观界面能差腐蚀、宏观氧浓差电池腐蚀的作用显著增大了试样的腐蚀电流,使得在整个溶液浓度范围内含界面的铜腐蚀电流均高于不含界面的腐蚀电流,同时在铜表面留下清晰的界面腐蚀线;通过对界面腐蚀电流的剥离,包含液相主体腐蚀部分时无论有无界面的铜腐蚀速率均随Cl^-浓度的升高呈现先增大后减小的趋势,而去除液相部分影响的单独界面腐蚀电流则随Cl^-浓度升高而增大。     

过氧化氢催化氧化法处理高浓度含氰废水研究

采用过氧化氢催化氧化法处理高浓度含氰废水,考察了过氧化氢浓度、铜离子浓度、反应pH值及反应时间等反应条件对总氰化物去除效果的影响。研究结果表明,当总氰化物的质量浓度为874 mg/L时,在过氧化氢的质量浓度为3.09 g/L、铜离子的质量浓度为50 mg/L、反应pH值为9、反应时间为1 h的最佳条件下,总氰化物去除率达到97.6%。铜离子能加快过氧化氢氧化氰根的反应速率。此外,在实际工程应用中,过氧化氢实际投加量比理论投加量要大。     

Chemical mechanical planarization of copper in alkaline slurry with uric acid as inhibitor

Chemical mechanical planarization of copper disks in hydrogen peroxide and l-arginine based alkaline slurry was investigated. Various commonly proposed inhibitors were screened by static etch rate experiments and only BTA and uric acid were found to be effective in the alkaline pH range, while potassium sorbate was moderately effective. The combination of arginine, hydrogen peroxide and uric acid leads to a more robust polish rate than can be achieved with glycine, hydrogen peroxide and BTA based slurries. The dissolution in presence of uric acid was further studied by potentiodynamic and cyclic polarization experiments which indicate formation of a passivation layer on the copper surface. Silicon dioxide wafers were polished to determine the Cu/silicon dioxide polish rate selectivity in alkaline pH range and a high selectivity (>100) was observed. These results indicate that it is possible to conduct a robust copper CMP with alkaline slurries while maintaining an excellent Cu/silicon dioxide polish rate selectivity.     

碱性阻挡层抛光液中ULK介质抛光性能的研究

研究了化学机械抛光(CMP)过程中抛光液的SiO₂磨料质量分数和表面活性剂对多孔SiOCH薄膜(ULK介质)介电常数(k)及抛光速率的影响。所用抛光液(pH=10)主要由0%~4%(质量分数,下同)SiO₂、0.075%H₂O₂、1%邻苯二甲酸氢钾和不同质量浓度的表面活性剂组成,其中表面活性剂为非离子表面活性剂脂肪醇聚氧乙烯醚(AEO-9和AEO-15)、阴离子表面活性剂十二烷基硫酸铵(ADS)和两亲性非离子表面活性剂辛基苯酚聚氧乙烯醚(OP-50)。结果表明,磨料质量分数的增大会使ULK介质的去除速率和k值都增大。聚醚类表面活性剂都能在CMP过程中很好地保护ULK介质表面,降低其去除速率,OP-50的效果尤其好。当采用2%SiO₂+0.075%H₂O₂+1%KHP+200 mg/L OP-50的抛光液进行CMP时,ULK介质的去除速率为5.2 nm/min,k值增幅低于2%,Cu和Co的去除速率基本不变。     

Electrochemical characterization of Cu dissolution and chemical mechanical polishing in ammonium hydroxide–hydrogen peroxide based slurries

Chemical mechanical polishing (CMP) of copper in ammonium hydroxide based slurry in the presence of hydrogen peroxide was investigated. The polishing trend was found to be similar to that exhibited by other slurries containing hydrogen peroxide and various complexing agents used for Cu CMP. When the hydrogen peroxide concentration is increased, the polish rate increases, reaches a maximum and then decreases. The location and the magnitude of the maximum depend on the ammonium hydroxide concentration. The dissolution of copper in the NH₄OH–hydrogen peroxide solution was probed by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) experiments. Electrical equivalent circuit (EEC) and reaction mechanism analysis (RMA) were employed to determine the mechanistic reaction pathway of Cu dissolution in NH₄OH–hydrogen peroxide system. Based on the RMA analysis, a four step catalytic mechanism with two adsorbed intermediate species is proposed.     

过氧化氢体系化学退镍液的正交试验优化

以对环境友好的过氧化氢作为氧化剂对镀镍铜板进行退镍处理,代替传统的硝酸溶液.通过正交试验考察了过氧化氢、六次甲基四胺、柠檬酸钠和过氧化氢稳定剂(由质量比1:1的硅酸钠和氯化镁组成)的质量浓度对退镍速率的影响,用金相显微镜观察了退镍后铜板的表面状态.结果表明,在55°C、pH为4的条件下,在含60 g/L过氧化氢、12 ...     

Effect of hydrogen peroxide on oxidation of copper in CMP slurries containing glycine and Cu ions

This study compares the oxidative dissolution, passivation, and polishing behavior of copper chemical-mechanical polishing in the presence of hydrogen peroxide, glycine, and copper sulfate. High purity discs were used to study the dissolution and oxidation kinetics under static and dynamic conditions at pH 4 with varying H₂O₂ concentrations. Changes in surface chemistry of the statically etched copper disc were investigated using X-ray photoelectron spectroscopy (XPS). In the presence of H₂O₂, the copper removal rate reached a maximum at 1% H₂O₂ concentration, and decreased with further increase in H₂O₂ concentration. Electrochemical studies indicate a strong passivation process at higher H₂O₂ concentrations due to the rapid formation of oxide on the surface. With the further addition of glycine and copper sulfate to the slurry, the copper removal rates increased significantly and the maximum removal rate shifted to a H₂O₂ concentration of 3%. Electrochemical investigation indicates an enhanced dissolution of copper, which might be due to the strong catalytic activity of Cu(II)-glycine complexes in decomposing H₂O₂ to yield hydroxyl radicals. XPS results suggest that the passivation at higher H₂O₂ concentrations in the presence of glycine and copper sulfate is provided by the OH radicals adsorbed on Cu surface.     

OXIDATION OF C.I. ACID ORANGE 7 WITH OZONE AND HYDROGEN PEROXIDE IN A HOLLOW FIBER MEMBRANE REACTOR

The degradation of C.I. Acid Orange 7 by ozone combined with hydrogen peroxide was carried out in a hollow fiber membrane reactor, and batch recirculation mode of aqueous phase was employed. The effect of initial pH, hydroxyl radical scavenger, hydrogen peroxide concentration, liquid recirculation rate, gas flow rate, and gaseous ozone concentration on the decolorization of C.I. Acid Orange 7 was investigated. The results showed that the decolorization of C.I. Acid Orange 7 fits the pseudo-half-order kinetic model. The rate constant increased with the increase of initial pH, hydrogen peroxide concentration, liquid recirculation rate, gas flow rate, and gaseous ozone concentration. The presence of hydroxyl radical scavenger inhibited the decolorization rate by over 50%. The combination of ozone with hydrogen peroxide achieved a higher COD removal efficiency than ozone alone in the membrane reactor.     

化学机械抛光中Co/Ti电偶腐蚀与去除速率选择性研究

通过电化学测试研究了pH、配位剂(柠檬酸钾)和缓蚀剂[包括1,2,4-三氮唑(TAZ)和3-氨基-5-巯基-1,2,4-三氮唑(AMTA)]对Co/Ti电偶腐蚀的影响.结果表明,溶液pH升高会增大Co与Ti之间的腐蚀电位差.当pH=8时,加入0.5％(质量分数)柠檬酸钾会加剧Co和Ti之间的电偶腐蚀,而再加入缓蚀剂TA...     

铜及铜合金不同化学抛光工艺研究

对铜及铜合金化学抛光工艺进行了研究,考察了低浓度硝酸体系和双氧水体系对铜及其合金的抛光亮度、腐蚀失重以及对环境污染程度的影响。结果表明,低浓度硝酸体系抛光亮度高,适用范围广,对环境的污染较传统三酸体系少,虽然对铜及铜合金有一定的腐蚀,但返工对工件的尺寸影响不大,适用于冰箱、空调器等的蒸发管的抛光。双氧水抛光体系对铜及其合金腐蚀轻微,对环境的污染更少,但成本相对较高,适于对加工尺寸要求严格的铜及铜合金电子元件的化学抛光。     

CuO/γ-Al2O3催化湿式过氧化水溶液中苯酚

研究了以CuO/γ-Al2O3为催化剂、H2O2为氧化剂的催化湿式过氧化技术对苯酚的降解效果,主要考察了H2O2含量、处理温度对苯酚去除率及TOC去除率的影响。结果表明：苯酚去除率及TOC去除率均随着H2O2含量的增加及处理温度的升高而增大;在苯酚初始浓度为200 mg/L、H2O2的初始含量为600 mg/L、pH值为5.0、处理温度为50 ℃时,处理2.0 h后苯酚去除率达到100％,TOC去除率可达到96.6％。ICP分析表明,溶液中Cu2+浓度随着H2O2含量和处理温度有微小的增大,结合HPLC分析可能是由于苯酚降解过程中产生的羧酸与CuO发生了反应。