AlCrTaTiZrV高熵合金氮化物扩散阻挡层的制备及其热稳定性

doi:10.13251/j.issn.0254-6051.2021.09.039

摘要/Abstract

摘要： 为研究氮气含量的变化对AlCrTaTiZrV高熵合金薄膜性能的影响,检验在最佳氮气含量下厚度为15 nm的(AlCrTaTiZrV)N扩散阻挡层的热稳定性。采用直流磁控溅射设备在N型Si(111)基底上溅射不同氮气含量的高熵合金氮化物;选取最佳氮气含量为制备条件,在硅基底上沉积15 nm厚的AlCrTaTiZrVN₁₀高熵合金氮化物为扩散阻挡层,并在阻挡层顶部沉积50 nm厚度的Cu膜,最终形成Si/AlCrTaTiZrVN₁₀/Cu三层堆叠结构。利用真空退火炉将Si/AlCrTaTiZrVN₁₀/Cu薄膜体系在500 ℃下进行不同时间的退火处理,用以模拟恶劣的工作环境。利用场发射扫描电子显微镜(FESEM)、原子力显微镜(AFM)、X射线衍射仪(XRD)及四探针电阻测试仪(FPP)对试样的表面形貌、粗糙度、物相组成及方块电阻和进行表征。试验结果为:当氮气含量低于10%时,高熵合金氮化物薄膜为非晶结构。当氮气含量为20%时,高熵合金氮化物薄膜呈现FCC结构,并随着氮气含量的增加,薄膜的结晶性得到提高。薄膜表面的粗糙度在氮气含量为10%时最低,R_a仅为0.124 nm。三层堆叠结构500 ℃退火8 h后,Cu表面发生团聚,薄膜的方阻维持在较低的0.070 Ω/□,且并未发现Cu-Si化合物。厚度为15 nm的非晶结构AlCrTaTiZrVN₁₀薄膜在500 ℃退火8 h后,依旧可以抑制Cu的扩散,表现出了优异的热稳定性及扩散阻挡性能。

关键词: 高熵合金, 扩散阻挡层, 氮化物薄膜, 非晶结构, 退火, 热稳定性

Abstract: The work aimed to study the effect of different nitrogen flow rates on the properties of AlCrTaTiZrV high-entropy alloy nitride films and to examine the thermal stability of (AlCrTaTiZrV)N diffusion barrier layer with a thickness of 15 nm under the optimum nitrogen content. The (AlCrTaTiZrV)N high-entropy alloy nitride films were synthesized by reactive magnetron sputtering under different nitrogen flow. A 15 nm amorphous AlCrTaTiZrVN₁₀ film was prepared on single crystal silicon as a single-layer barrier material for Cu interconnection. A 50 nm-thick Cu film was deposited on the surface of the AlCrTaTiZrVN₁₀ film to obtain the Si/AlCrTaTiZrVN₁₀/Cu film system. To assess its thermal stability, Si/AlCrTaTiZrVN₁₀/Cu structure was annealed at 500 ℃ in high vacuum for various time to simulate real working conditions. The surface morphology, roughness, phase composition and sheet resistance of the specimens were characterized by means of the field emission scanning electron microscopy (FE-SEM), atomic force microscope (AFM), X-ray diffractometer (XRD) and four-point probe (FPP), respectively. The results show that the AlCrTaTiZrV high-entropy alloy thin film is amorphous structure when the nitrogen flow rate is less than 10%. When the nitrogen content is 20%, the high-entropy alloy nitride film presents FCC structure and the crystallinity of the film is improved with the increase of nitrogen content. When the nitrogen flow rate is 10%, the roughness is the lowest of only 0.124 nm. After annealed at 500 ℃ for 8 h, the grain size increases significantly. However, the sheet resistance of the films remain at a low value of 0.070 Ω/□, and no Cu-Si compound is formed. The amorphous structure of 15 nm AlCrTaTiZrVN₁₀ high-entropy alloy nitride film can effectively prevent the diffusion of Cu after annealing at 500 ℃ for 8 h, showing excellent thermal stability and good diffusion barrier properties on Cu.

Key words: high-entropy alloy, diffusion barrier layer, nitride film, amorphous structure, annealing, thermal stability

中图分类号:

TG174.4

李荣斌, 李珂, 蒋春霞, 张如林. AlCrTaTiZrV高熵合金氮化物扩散阻挡层的制备及其热稳定性[J]. 金属热处理, 2021, 46(9): 216-222.

Li Rongbin, Li Ke, Jiang Chunxia, Zhang Rulin. Preparation and thermal stability of AlCrTaTiZrV-nitride diffusion barrier layer[J]. Heat Treatment of Metals, 2021, 46(9): 216-222.

参考文献

[1]姜国华, 王楠, 赵波. 集成电路互连引线的研究进展[J]. 微纳电子技术, 2015(8): 477-484.
Jiang Guohua, Wang Nan, Zhao Bo. Research progress of the IC interconnection wire[J]. Micronanoelectronic Technology, 2015(8): 477-484.
[2]徐小城. 深亚微米集成电路工艺中铜金属互联技术[J]. 微电子技术, 2001(6): 1-7.
Xu Xiaocheng. On the interconnecting technology of metal copper used in IC with deep sub-micron processing[J]. Microelectronic Technology, 2001(6): 1-7.
[3]傅晓娟, 赵毅强, 刘峻, 等. 铜互连扩散阻挡层工艺优化[J]. 北京航空航天大学学报, 2020, 46(8): 1514-1520.
Fu Xiaojuan, Zhao Yiqiang, Liu Jun, et al. Optimization of diffusion barrier process on copper interconnection[J]. Journal of Beijing University of Aeronautics and Astronautics, 2020, 46(8): 1514-1520.
[4]Ogawa E T, Lee K D, Blaschke V A, et al. Electromigration reliability issues in dual-damascene Cu interconnections[J]. IEEE Transactions on Reliability, 2002, 54(4): 403-419.
[5]Wang Y, Zhao C H, Cao F, et al. Barrier capability of Zr-N films with different density and crystalline structure in Cu/Si contact systems[J]. Materials Letters, 2008, 62(21-22): 3761-3763.
[6]Wang Y, Chen X, Ma W, et al. Electroless deposition of NiCrB diffusion barrier layer film for ULSI-Cu metallization[J]. Applied Surface Science, 2017, 396: 333-338.
[7]Wu Z, Li R, Xie X, et al. PVD-treated ALD TaN for Cu interconnect extension to 5nm node and beyond[C]//2018 IEEE International Interconnect Technology Conference (IITC). 2018: 149-151.
[8]Wu K C, Tseng J Y, Chen W J. Electroplated Ru and RuCo films as a copper diffusion barrier[J]. Applied Surface Science, 2020, 516: 146139.
[9]陈海波, 周继承, 李幼真. 集成电路Cu互连扩散阻挡层的研究进展[J]. 材料导报, 2006, 20(12): 8-11.
Chen Haibo, Zhou Jicheng, Li Youzhen. Development of diffusion barrier for Cu interconnection in ULSI[J]. Materials Reports, 2006, 20(12): 8-11.
[10]Shacham-Diamand Y. Barrier layers for Cu ULSI metallization[J]. Journal of Electronic Materials, 2001, 30(4): 336-344.
[11]Uekubo M, Oku T, Nii K, et al. WN_x diffusion barriers between Si and Cu[J]. Thin Solid Films, 1996, 286(s1/2): 170-175.
[12]Qu X P, Tan J J, Zhou M, et al. Improved barrier properties of ultrathin Ru film with TaN interlayer for copper metallization[J]. Applied Physics Letters, 2006, 88: 151912.
[13]Lee H J, Hong T E, Kim S H. Atomic layer deposited self-forming Ru-Mn diffusion barrier for seedless Cu interconnects[J]. Journal of Alloys and Compounds, 2016, 686(25): 1025-1031.
[14]Meng Y, Song Z X, Qian D, et al. Thermal stability of RuZr alloy thin films as the diffusion barrier in Cu metallization[J]. Journal of Alloys and Compounds, 2014, 588: 461-464.
[15]Koike J, Wada M. Self-forming diffusion barrier layer in Cu-Mn alloy metallization[J]. Applied Physics Letters, 2005, 87: 041911.
[16]Dey S, Yu K H, Consiglio S, et al. Atomic layer deposited ultrathin metal nitride barrier layers for ruthenium interconnect applications[J]. Journal of Vacuum Science and Technology A, 2017, 35: 03E109.
[17]Xu H, Hu Z J, Qu X P, et al. Effect of thickness scaling on the permeability and thermal stability of Ta(N) diffusion barrier[J]. Applied Surface Science, 2019, 498: 143887.
[18]Meng Y, Song Z X, Chen J H, et al. Ultrathin ZrB_xO_y films as diffusion barriers in Cu interconnects[J]. Vacuum, 2015, 119: 1-6.
[19]Muhlbacher M, Greczynski G, Sartory B, et al. Enhanced Ti_0.84Ta_0.16N diffusion barriers, grown by a hybrid sputtering technique with no substrate heating, between Si(001) wafers and Cu overlayers[J]. Scientific Reports, 2018, 8: 5360.
[20]Meng Y, Song Z X, Li Y H, et al. Thermal stability of ultra thin Zr-B-N films as diffusion barrier between Cu and Si[J]. Applied Surface Science, 2020, 527: 146810.
[21]Lee J, Duh J G. Structural evolution of Zr-Cu-Ni-Al-N thin film metallic glass and its diffusion barrier performance in Cu-Si interconnect at elevated temperature[J]. Vacuum, 2017, 142: 81-86.
[22]Yeh J W, Chen S K, Lin S J, et al. Nanostructured high-entropy alloys with multiple principal elements: Novel alloy design concepts and outcomes[J]. Advanced Engineering Materials, 2004, 6: 299-303.
[23]Li W, Liu P, Liaw P K. Microstructures and properties of high-entropy alloy films and coatings: A review[J]. Materials Research Letters, 2018, 6: 199-229.
[24]贾岳飞, 王刚, 贾延东, 等. 轻质高熵合金研究现状[J]. 材料导报, 2020, 34(17): 17003-17017.
Jia Yuefei, Wang Gang, Jia Yandong, et al. Light-weight high-entropy alloy: A review[J]. Materials Reports, 2020, 34(17): 17003-17017.
[25]李荣斌, 黄天, 蒋春霞, 等. TaWTiVCr高熵合金薄膜的制备及微观结构、力学性能研究[J]. 表面技术, 2020, 49(6): 159-167.
Li Rongbin, Huang Tian, Jiang Chunxia, et al. Study on preparation, microstructure and mechanical properties of TaWTiVCr high entropy alloy thin film[J]. Surface Technology, 2020, 49(6): 159-167.
[26]Xu Y, Li G, Xia Y. Synthesis and characterization of super-hard AlCrTiVZr high-entropy alloy nitride films deposited by HiPIMS[J]. Applied Surface Science, 2020, 523: 14629.
[27]Dong Y S, Zhao W J, Li Y R, et al. Influence of silicon on the microstructure and mechanical properties of Zr-Si-N composite films[J]. Applied Surface Science, 2005, 252(14): 5057-5062.
[28]Chang S Y, Li C E, Chiang S C, et al. 4-nm thick multilayer structure of multicomponent (AlCrRuTaTiZr)N_x, as robust diffusion barrier for Cu interconnects[J]. Journal of Alloys and Compounds, 2012, 515: 4-7.
[29]Chang S Y, Chen D S. Ultrathin (AlCrTaTiZr)N_x/AlCrTaTiZr bilayer structures with high diffusion resistance for Cu interconnects[J]. Journal of the Electrochemical Society, 2010, 157 (6): G154-G159.
[30]Qu X P, Lu H, Tao P, et al. Effects of pre-annealing on the diffusion barrier properties for ultrathin W-Si-N thin film[J]. Thin Solid Film, 2004, 462: 67-71.
[31]Fu T, Shen Y G, Zhou Z F, et al. Surface morphology of sputter deposited W-Si-N composite coatings characterized by atomic force microscopy[J]. Materials Science and Engineering B, 2005, 123(2): 158-162.