化学学报 ›› 2013, Vol. 71 ›› Issue (08): 1111-1117.DOI: 10.6023/A13030326 上一篇    下一篇

综述

Ge2Sb2Te5的化学机械抛光研究进展

何敖东a,b, 刘波a, 宋志棠a, 冯高明c, 朱南飞c, 任佳栋c, 吴关平c, 封松林a   

  1. a 中国科学院上海微系统与信息技术研究所 信息功能材料国家重点实验室 上海 200050;
    b 中国科学院大学 北京 100083;
    c 中芯国际集成电路制造公司 上海 201203
  • 收稿日期:2013-03-24 出版日期:2013-08-14 发布日期:2013-05-06
  • 通讯作者: 刘波, E-mail: liubo@mail.sim.ac.cn E-mail:liubo@mail.sim.ac.cn
  • 基金资助:

    项目受国家重点基础研究发展计划(Nos. 2010CB934300, 2011CBA00607, 2011CB9328004)、国家集成电路重大专项(No. 2009ZX02023-003)、国家自然科学基金(Nos. 60906004, 60906003, 61006087, 61076121, 61176122, 61106001)、上海市科委(12nm0503701)资助.

Research and Development of Chemical Mechanical Planarization for Ge2Sb2Te5

He Aodonga,b, Liu Boa, Song Zhitanga, Feng Gaomingc, Zhu Nanfeic, Ren Jiadongc, Wu Guanpingc, Feng Songlinga   

  1. a State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Micro-system and Information Technology, Chinese Academy of Sciences, Shanghai 200050;
    b University of the Chinese Academy of Sciences, Beijing 100049, China;
    c Semiconductor Manufacturing International Corporation, Shanghai 201203, China
  • Received:2013-03-24 Online:2013-08-14 Published:2013-05-06
  • Supported by:

    Project Supported by the National Key Basic Research Program of China (Nos. 2010CB934300, 2011CBA00607, 2011CB9328004), National Integrate Circuit Research Program of China (2009ZX02023-003), National Natural Science Foundation of China (60906004, 60906003, 61006087, 61076121, 61176122, 61106001), Science and Technology Council of Shanghai (12nm0503701).

相变存储器由于具有非易失性、高速度、低功耗等优点被认为最有可能成为下一代存储器的主流产品, Ge2Sb2Te5(GST)作为一种传统相变材料已经被广泛应用在相变存储器中, 而GST的化学机械抛光作为相变存储器生产的关键工艺目前已被采用. 本工作综述了有关GST的化学机械抛光技术研究进展, 讨论了GST化学机械抛光过程的影响因素, 如下压力、转速、抛光垫、磨料、氧化剂、表面活性剂等, 并对目前GST的化学机械抛光机理进行了归纳, 进一步展望了GST的化学机械抛光技术的发展前景.

关键词: Ge2Sb2Te5, 化学机械抛光, 相变存储器

Phase change memory (PCM) is considered a major candidate for next-generation memory due to its nonvolatile, fast program access times, low consumable power. So far chalcogenide Ge2Sb2Te5 (GST), as a traditional phase material, has been widely adopted and investigated for PCM application. Recently, chemical mechanical planarization (CMP) of GST as a key technique for confined structure has been applied in the fabrication of PCM. In this paper, research and development of CMP for GST is reviewed firstly and the impact factors of down force, rotation velocity, polishing pads, and the slurry on the GST CMP are discussed. For the mechanical parameter, the removal rate (RR) of GST increases with the increasing of pressure and rotation velocity firstly, and then reaches saturation or slightly decreases. The gentle mechanical parameter is a better choice for GST CMP due to its lower hardness. With regard to polishing pads, GST polished using Politex reg can attain a better surface quality, and almost no residue and scratches can be found, compared with IC1010. The oxidizer of slurry, such as H2O2, (NH4)2S2O8, KMnO4 and FeCl3 have a great influence on the GST performance, the oxidization capacity of each element in GST alloy is different. Among these elements, Ge is preferentially oxidized, but Te is hard oxidized due to their different electronegativity. RR strongly depends on the pH of slurry, it reaches high RR in the strong acidic and alkaline condition. The stable species for GST in the slurries at pH 2 are GeO2, Sb2O3 and Te both for the situations with and without H2O2, while they are, and for those at pH 11. Usually, the GST polished follows a corrosion polishing mechanism and cyclic reaction polishing mechanism in the different conditions. For corrosion polishing mechanism, it involves the direct touching between the GST film and the abrasives of slurry. For the cyclic reaction polishing mechanism, it involves passivation by an oxidized GST layer firstly, then mechanical polishing between the oxidized GST surface and abrasives, and repassivation. Although the GST CMP process exhibits better electrical performance for the PCM, it was very difficult to get the desirable GST CMP solutions due to the complicated GST material characteristics such as density, composition, doped component, and so on. The suitable slurry composition, optimal polishing process and suitable polishing pad need to be investigated further, especially below 30 nm complementary metal oxide semiconductor process node.

Key words: Ge2Sb2Te5, chemical mechanical planarization, phase change memory