SEMICONDUCTOR TECHNOLOGY

CMP process optimization using alkaline bulk copper slurry on a 300 mm Applied Materials Reflexion LK system

Chenwei Wang, Suohui Ma, Yuling Liu, Rui Chen and Yang Cao

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 Corresponding author: Wang Chenwei, cwtjy206@163.com

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Abstract: CMP process optimization for bulk copper removal based on alkaline copper slurry was performed on a 300 mm Applied Materials Reflexion LK system. Under the DOE condition, we conclude that as the pressure increases, the removal rate increases and non-uniformity is improved. As the slurry flow rate increases, there is no significant improvement in the material removal rate, but it does slightly reduce the WIWNU and thus improve uniformity. The optimal variables are obtained at a reduced pressure of 1.5 psi and a slurry flow rate of 300 ml/min. Platen/carrier rotary speed is set at a constant value of 97/103 rpm. We obtain optimized CMP characteristics including a removal rate over 6452 Å/min and non-uniformity below 4% on blanket wafer and the step height is reduced by nearly 8000 Å/min in the center of the wafer on eight layers of copper patterned wafer, the surface roughness is reduced to 0.225 nm.

Key words: CMP processoptimizationalkaline copper slurrydesign of experiment



[1]
Tsai T H, Yen S C. Localized corrosion effects and modific-ations of acidic and alkaline slurries on copper chemical mechanical polishing. Appl Surf Sci, 2003, 210:190 doi: 10.1016/S0169-4332(02)01224-2
[2]
Liu X Y, Liu Y L, Liang Y, et al. Effect of slurry components on chemical mechanical polishing of copper at low down pressure and a chemical kinetics model. Thin Solid Films, 2011, 520:400 doi: 10.1016/j.tsf.2011.06.050
[3]
Hernandez J, Wrschka P, Oehrlein G S. Surface chemistry studies of copper chemical mechanical planarization. J Electrochem Soc, 2001, 148(7):G389 http://cat.inist.fr/?aModele=afficheN&cpsidt=1095187
[4]
Lee H, Park B, Jeong H. Influence of slurry components on uniformity in copper chemical mechanical planarization. Microelectron Eng, 2008, 85:689 doi: 10.1016/j.mee.2007.12.044
[5]
Pandija S, Roy D, Babu S V. Achievement of high planarization efficiency in CMP of copper at a reduced down pressure. Microelectron Eng, 2009, 86:367 doi: 10.1016/j.mee.2008.11.047
[6]
Nagar M, Vaes J, Ein-Eli Y. Potassium sorbate as an inhibitor in copper chemical mechanical planarization slurries. Part Ⅱ:effects of sorbate on chemical mechanical planarization performance. Electrochim Acta, 2010, 55:2810 doi: 10.1016/j.electacta.2009.10.086
[7]
Du T, Luo Y, Desai V. The combinatorial effect of complexing agent and inhibitor on chemical-mechanical planarization of copper. Microelectron Eng, 2004, 71:90 doi: 10.1016/j.mee.2003.08.008
[8]
Nagendra Prasad Y, Ramanathan S. Chemical mechanical planarization of copper in alkaline slurry with uric acid as inhibitor. Electrochim Acta, 2007, 52:6353 doi: 10.1016/j.electacta.2007.04.044
[9]
Luo Q, Campbell D R, Babu S V. Chemical-mechanical polishing of copper in alkaline media. Thin Solid Films, 1997, 311:177 doi: 10.1016/S0040-6090(97)00454-9
Fig. 1.  Material removal rate and WIWNU after CMP as a function of various pressures.

Fig. 2.  Material removal rate and WIWNU after CMP as a function of different slurry flow rates.

Fig. 3.  Step height reduction of eight-layer copper pattern wafers at different positions as a function of polishing time.

Fig. 4.  3D AFM image and surface roughness (a) before and (b) after CMP.

Table 1.   Parameters of CMP equipment for DOE technique.

[1]
Tsai T H, Yen S C. Localized corrosion effects and modific-ations of acidic and alkaline slurries on copper chemical mechanical polishing. Appl Surf Sci, 2003, 210:190 doi: 10.1016/S0169-4332(02)01224-2
[2]
Liu X Y, Liu Y L, Liang Y, et al. Effect of slurry components on chemical mechanical polishing of copper at low down pressure and a chemical kinetics model. Thin Solid Films, 2011, 520:400 doi: 10.1016/j.tsf.2011.06.050
[3]
Hernandez J, Wrschka P, Oehrlein G S. Surface chemistry studies of copper chemical mechanical planarization. J Electrochem Soc, 2001, 148(7):G389 http://cat.inist.fr/?aModele=afficheN&cpsidt=1095187
[4]
Lee H, Park B, Jeong H. Influence of slurry components on uniformity in copper chemical mechanical planarization. Microelectron Eng, 2008, 85:689 doi: 10.1016/j.mee.2007.12.044
[5]
Pandija S, Roy D, Babu S V. Achievement of high planarization efficiency in CMP of copper at a reduced down pressure. Microelectron Eng, 2009, 86:367 doi: 10.1016/j.mee.2008.11.047
[6]
Nagar M, Vaes J, Ein-Eli Y. Potassium sorbate as an inhibitor in copper chemical mechanical planarization slurries. Part Ⅱ:effects of sorbate on chemical mechanical planarization performance. Electrochim Acta, 2010, 55:2810 doi: 10.1016/j.electacta.2009.10.086
[7]
Du T, Luo Y, Desai V. The combinatorial effect of complexing agent and inhibitor on chemical-mechanical planarization of copper. Microelectron Eng, 2004, 71:90 doi: 10.1016/j.mee.2003.08.008
[8]
Nagendra Prasad Y, Ramanathan S. Chemical mechanical planarization of copper in alkaline slurry with uric acid as inhibitor. Electrochim Acta, 2007, 52:6353 doi: 10.1016/j.electacta.2007.04.044
[9]
Luo Q, Campbell D R, Babu S V. Chemical-mechanical polishing of copper in alkaline media. Thin Solid Films, 1997, 311:177 doi: 10.1016/S0040-6090(97)00454-9
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    Received: 15 April 2013 Revised: 13 June 2013 Online: Published: 01 December 2013

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      Chenwei Wang, Suohui Ma, Yuling Liu, Rui Chen, Yang Cao. CMP process optimization using alkaline bulk copper slurry on a 300 mm Applied Materials Reflexion LK system[J]. Journal of Semiconductors, 2013, 34(12): 126001. doi: 10.1088/1674-4926/34/12/126001 C W Wang, S H Ma, Y L Liu, R Chen, Y Cao. CMP process optimization using alkaline bulk copper slurry on a 300 mm Applied Materials Reflexion LK system[J]. J. Semicond., 2013, 34(12): 126001. doi: 10.1088/1674-4926/34/12/126001.Export: BibTex EndNote
      Citation:
      Chenwei Wang, Suohui Ma, Yuling Liu, Rui Chen, Yang Cao. CMP process optimization using alkaline bulk copper slurry on a 300 mm Applied Materials Reflexion LK system[J]. Journal of Semiconductors, 2013, 34(12): 126001. doi: 10.1088/1674-4926/34/12/126001

      C W Wang, S H Ma, Y L Liu, R Chen, Y Cao. CMP process optimization using alkaline bulk copper slurry on a 300 mm Applied Materials Reflexion LK system[J]. J. Semicond., 2013, 34(12): 126001. doi: 10.1088/1674-4926/34/12/126001.
      Export: BibTex EndNote

      CMP process optimization using alkaline bulk copper slurry on a 300 mm Applied Materials Reflexion LK system

      doi: 10.1088/1674-4926/34/12/126001
      Funds:

      Project supported by the Major National Science and Technology Special Projects (No. 2009ZX02308), the Tianjin Natural Science Foundation of China (No. 10JCZDJC15500), the National Natural Science Foundation of China (No. 10676008), and the Fund Project of the Hebei Provincial Department of Education (No. 2011128)

      the National Natural Science Foundation of China 10676008

      the Tianjin Natural Science Foundation of China 10JCZDJC15500

      the Fund Project of the Hebei Provincial Department of Education 2011128

      the Major National Science and Technology Special Projects 2009ZX02308

      More Information
      • Corresponding author: Wang Chenwei, cwtjy206@163.com
      • Received Date: 2013-04-15
      • Revised Date: 2013-06-13
      • Published Date: 2013-12-01

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