### Ge2Sb2Te5的化学机械抛光研究进展

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
• 投稿日期:2013-03-24 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 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).

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.