阴离子表面活性剂及复配对阻挡层抛光液性能的影响

Effect of Anionic Surfactant and Its Compound on the Properties of Barrier Layer Slurry

为提高铜互连化学机械抛光(CMP)后表面质量,在抛光液中需引入适当的表面活性剂以改善磨料的稳定性以及CMP后铜的表面粗糙度。研究了十二烷基硫酸铵(ADSA)、脂肪醇聚氧乙烯醚硫酸铵(AESA)、直链烷基苯磺酸(LABSA)3种不同阴离子表面活性剂,以及非离子表面活性剂脂肪醇聚氧乙烯醚(AEO-9)和LABSA复配表面活性剂对钽阻挡层抛光液润湿性、分散性以及对材料去除速率的影响。通过接触角测量仪、纳米粒度仪、扫描电镜和原子力显微镜测试表面张力、接触角、大颗粒数、粒径分布以及CMP后铜的表面粗糙度,并分析复配表面活性剂的作用机制。结果表明:抛光液中加入LABSA后,因其具有直链型结构,抛光液的润湿性和分散性效果最好,抛光后铜表面的粗糙度最低;AEO-9和LABSA进行复配,相较于单一的LABSA,抛光液的润湿性、分散性、稳定性和抛光后铜表面粗糙度均有所改善,体积分数0.1%LABSA+0.1%AEO-9的复配表面活性剂性能最优,CMP后铜表面粗糙度降至0.7 nm。

To improve the surface quality after chemical mechanical polishing(CMP)of copper interconnects,appropriate surfactants need to be introduced into the slurry to improve the stability of the abrasive as well as the surface roughness of the copper after CMP.The effects of three anionic surfactants of ammonium dodecyl sulfate(ADSA),fatty alcohol polyoxyethylene ether ammonium sulfate(AESA)and linear alkyl benzene sulfonic acid(LABSA),and the composite surfactant of nonionic surfactant faty alcohol polyoxyethylene ether(AEO-9)and anionic surfactant LABSA,on the slurry and polishing performance of Ta barrier layer were investigated.The surface tension,contact angle,large particle count,particle size distribution and copper surface roughness were characterized by contact angle measuring instrument,nanoparticle size analyzer,scanning electron microscope and atomic force microscope,and the action mechanism of the composite surfactant was analyzed.The results show that due to the linear chain structure of LABSA,the wettability and dispersion of the slurry after adding LABSA are the best and the roughness of the polished copper surface is the lowest.Compared with the single LABSA,the wettability,dispersion and stability of the slurry and surface roughness of copper after CMP are improved with the addition of composite surfactant.The performance of slurry with composite surfactant composed of 0.1%LABSA+0.1%AEO-9 is the best,and the roughness of the polished copper surface decreases to 0.7 nm.