Research on Grain Refinement Process and Microstructure of Ultra-High Purity Copper Used for Integrated Circuit

Abstract:

In this paper, the deformation and annealing process of ultra-high purity copper used for Ultra large-scale integration (ULSI) have been investigated. The evolution of grain size and texture during deforming and annealing were analyzed. The results show that the coarse cast structure can be efficiently eliminated by multiple forging and the grain size can be refined initially. Ultra-high purity copper with cold rolling begins to recrystallize at a temperature of 150°C. Especially, when the cold rolling deformation is 80%, the average grain size is about 17.9μm after optimized annealing. The typical rolling textures after deformation are not strong and a large number of low-angle grain boundaries are found. After annealing, the rolling texture and recrystallization texture come to co-existence. The texture distribution is uniform without strong grain orientation and high-angle boundaries demonstrate in the microstructure.

• Periodical: Materials Science Forum (Volume 852)
• Pages: 601-606
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.852.601
• Online since: April 2016
• Authors: Xiang Zeng, Jin Jiang He, Xuan Jiang, Hao Zeng, Xiao Yong Wan, Zai Yan Shang
• Keywords: Grain Refinement, Recrystallization, Texture, Ultra High Purity Copper

References

[1] Hu C-K., Harper J. M. E. Copper interconnections and reliability [J]. Mater. Chem. Phys., 1998, 52: 5-16.

[2] Gao Yan, Wang Xinping, He Jinjiang, et. Research on copper sputtering targets in ULSI and related problems [J]. Semiconductor Technology, 2011, 36(11): 826-830.

[3] Hoon Cho. Development Of Copper Sputtering Target With Superior Sputter Yield Via Crystallographic Texture Control Annealing [J]. Modern Physics Letters B, 2009, 23(31&32): 3893-3896.

DOI: 10.1142/s021798490902196x

[4] Janine K. Kardokus, Chi tse Wu, Christopher L. Parfeniuk, Jane E. Buehler. Methods of forming copper-containing sputtering targets [P]. US 6849139, (2005).

[5] W. Gao, A. Belyakov 1, H. Miura, T. Sakai. Dynamic recrystallization of copper polycrystals with different purities [J]. Materials Science and Engineering A265 (1999) 233–239.

DOI: 10.1016/s0921-5093(99)00004-0

[6] Mao Weimin. Recrystallization and grain growth of metals[M]. Metallurgical Industry Press, 1993: 38.

[7] Zhu Xiaoguang, Liu Shuqin, Wan Xiaoyong, et. Research on Static recrystallization microstructure evolution of super high-purity silver [J]. Materials Review, 2014, 28(3): 97-100.

[8] Liu Xinjiang, Wang Jianzhong, Cang Daqiang. Effect of electric pulse modification on recrystallizing temperature of pure copper [J]. Heat Treatment, 2006, 35(10).

[9] Zhu Dachuan, Chen Jiazhao, Li Ning, et. Effect of lithium on recrystallization temperature of pure copper[J]. Rare Metal Materials and Engineering, 2001, 30(2): 157-159.

[10] Cui Zhongqi. Metallurgy and Heat Treatment [M]. China Machine Press, 1988: 214.

[11] Mao Weimin. The metal material crystallographic texture and anisotropy [M]. Science Press, 2002: 33.

[12] Chang Liang, Zeng Xiaoqin, Ding Wenjiang. Microstructure and texture of Mg alloy sheets fabricated by different rolling methods [J]. Light Alloy Fabrication Technology. 2007, 35(4): 4-9, 53.