SEMICONDUCTOR TECHNOLOGY

Effect of chelating agent concentration in alkaline Cu CMP process under the condition of different applied pressures

Haobo Yuan, Yuling Liu, Mengting Jiang, Weijuan Liu and Guodong Chen

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 Corresponding author: Yuan Haobo, Email:237607378@qq.com

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Abstract: We propose the action mechanism of Cu chemical mechanical planarization (CMP) in an alkaline solution. Meanwhile, the effect of abrasive mass fraction on the copper removal rate and within wafer non-uniformity (WIWNU) have been researched. In addition, we have also investigated the synergistic effect between the applied pressure and the FA/O chelating agent on the copper removal rate and WIWNU in the CMP process. Based on the experimental results, we chose several concentrations of the FA/O chelating agent, which added in the slurry can obtain a relatively high removal rate and a low WIWNU after polishing, to investigate the planarization performance of the copper slurry under different applied pressure conditions. The results demonstrate that the copper removal rate can reach 6125 Å/min when the abrasive concentration is 3 wt.%. From the planarization experimental results, we can see that the residual step height is 562 Å after excessive copper of the wafer surface is eliminated. It denotes that a good polishing result is acquired when the FA/O chelating agent concentration and applied pressure are fixed at 3 vol% and 1 psi, respectively. All the results set forth here are very valuable for the research and development of alkaline slurry.

Key words: alkaline slurryCu CMPsynergistic effectplanarizationstep height



[1]
Ma T, Chen L, Ruan W B. An interconnect sheet resistance model considering CMP pattern effects in 45 nm process. Physics Procedia, 2012, 25:110 doi: 10.1016/j.phpro.2012.03.058
[2]
Takaya Y, Kishida H, Hayashi T. Chemical mechanical polishing of patterned copper wafer surface using water-soluble fullerenol slurry. CIRP Annals-Manufacturing Technology, 2011, 60(1):567 doi: 10.1016/j.cirp.2011.03.068
[3]
Li Y, Liu Y L, Niu X H. Application of a macromolecular chelating agent in chemical mechanical polishing of copper film under the condition of low pressure and low abrasive concentration. Journal of Semiconductors, 2014, 35(1):016001 doi: 10.1088/1674-4926/35/1/016001
[4]
Hu Y, Liu Y L, Liu X Y. Effect of alkaline slurry on the electric character of the pattern Cu wafer. Journal of Semiconductors, 2011, 32(7):076002 doi: 10.1088/1674-4926/32/7/076002
[5]
Wang C W, Ma S H, Liu Y L. CMP process optimization using alkaline bulk copper slurry on a 300 mm applied materials reflexion LK system. Journal of Semiconductors, 2013, 34(12):126001 doi: 10.1088/1674-4926/34/12/126001
[6]
Wang C W, Liu Y L, Tian J Y. A study on the comparison of CMP performance between a novel alkaline slurry and a commercial slurry for barrier removal. Microelectron Eng, 2012, 98(2):29
[7]
Wang C W, Gao J J, Tian J Y. Chemical mechanical planarization of barrier layers by using a weakly alkaline slurry. Microelectron Eng, 2013, 108:71 doi: 10.1016/j.mee.2013.04.001
[8]
Yin K D, Wang S L, Liu Y L. Evaluation of planarization capability of copper slurry in the CMP process. Journal of Semiconductors, 2013, 34(3):036002 doi: 10.1088/1674-4926/34/3/036002
[9]
Chen R, Kang J, Liu Y L. A new weakly alkaline slurry for copper planarization at a reduced down pressure. Journal of Semiconductors, 2014, 35(2):026005 doi: 10.1088/1674-4926/35/2/026005
[10]
Liu X Y, Liu Y L, Liang Y. Effect of slurry components on chemical mechanical polishing of copper at low down pressure and a chemical kinetics model. Thin Solid Films, 2011, 520(1):400 doi: 10.1016/j.tsf.2011.06.050
Fig. 1.  The schematic diagram of copper CMP platform

Fig. 2.  Cross section view of the 300 mm copper wafer. (a) Copper blanket wafer. (b) Copper pattern wafer

Fig. 3.  The test position of the copper wafer. (a) The step height test position on the pattern wafer. (b) The measurement points position on the blanket wafer

Fig. 4.  Effect of abrasive concentration on the removal rate and WIWNU

Fig. 5.  The influence of the combined action between the applied pressure and FA/O chelating agent on (a) the copper removal rate and (b) the WIWNU

Fig. 6.  The residual step height after polishing under different pressures and concentrations of FA/O chelating agent

Table 1.   The removal rate and WIWNU of polishing experiments

[1]
Ma T, Chen L, Ruan W B. An interconnect sheet resistance model considering CMP pattern effects in 45 nm process. Physics Procedia, 2012, 25:110 doi: 10.1016/j.phpro.2012.03.058
[2]
Takaya Y, Kishida H, Hayashi T. Chemical mechanical polishing of patterned copper wafer surface using water-soluble fullerenol slurry. CIRP Annals-Manufacturing Technology, 2011, 60(1):567 doi: 10.1016/j.cirp.2011.03.068
[3]
Li Y, Liu Y L, Niu X H. Application of a macromolecular chelating agent in chemical mechanical polishing of copper film under the condition of low pressure and low abrasive concentration. Journal of Semiconductors, 2014, 35(1):016001 doi: 10.1088/1674-4926/35/1/016001
[4]
Hu Y, Liu Y L, Liu X Y. Effect of alkaline slurry on the electric character of the pattern Cu wafer. Journal of Semiconductors, 2011, 32(7):076002 doi: 10.1088/1674-4926/32/7/076002
[5]
Wang C W, Ma S H, Liu Y L. CMP process optimization using alkaline bulk copper slurry on a 300 mm applied materials reflexion LK system. Journal of Semiconductors, 2013, 34(12):126001 doi: 10.1088/1674-4926/34/12/126001
[6]
Wang C W, Liu Y L, Tian J Y. A study on the comparison of CMP performance between a novel alkaline slurry and a commercial slurry for barrier removal. Microelectron Eng, 2012, 98(2):29
[7]
Wang C W, Gao J J, Tian J Y. Chemical mechanical planarization of barrier layers by using a weakly alkaline slurry. Microelectron Eng, 2013, 108:71 doi: 10.1016/j.mee.2013.04.001
[8]
Yin K D, Wang S L, Liu Y L. Evaluation of planarization capability of copper slurry in the CMP process. Journal of Semiconductors, 2013, 34(3):036002 doi: 10.1088/1674-4926/34/3/036002
[9]
Chen R, Kang J, Liu Y L. A new weakly alkaline slurry for copper planarization at a reduced down pressure. Journal of Semiconductors, 2014, 35(2):026005 doi: 10.1088/1674-4926/35/2/026005
[10]
Liu X Y, Liu Y L, Liang Y. Effect of slurry components on chemical mechanical polishing of copper at low down pressure and a chemical kinetics model. Thin Solid Films, 2011, 520(1):400 doi: 10.1016/j.tsf.2011.06.050
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    Received: 09 April 2014 Revised: 20 May 2014 Online: Published: 01 November 2014

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      Haobo Yuan, Yuling Liu, Mengting Jiang, Weijuan Liu, Guodong Chen. Effect of chelating agent concentration in alkaline Cu CMP process under the condition of different applied pressures[J]. Journal of Semiconductors, 2014, 35(11): 116005. doi: 10.1088/1674-4926/35/11/116005 H B Yuan, Y L Liu, M T Jiang, W J Liu, G D Chen. Effect of chelating agent concentration in alkaline Cu CMP process under the condition of different applied pressures[J]. J. Semicond., 2014, 35(11): 116005. doi: 10.1088/1674-4926/35/11/116005.Export: BibTex EndNote
      Citation:
      Haobo Yuan, Yuling Liu, Mengting Jiang, Weijuan Liu, Guodong Chen. Effect of chelating agent concentration in alkaline Cu CMP process under the condition of different applied pressures[J]. Journal of Semiconductors, 2014, 35(11): 116005. doi: 10.1088/1674-4926/35/11/116005

      H B Yuan, Y L Liu, M T Jiang, W J Liu, G D Chen. Effect of chelating agent concentration in alkaline Cu CMP process under the condition of different applied pressures[J]. J. Semicond., 2014, 35(11): 116005. doi: 10.1088/1674-4926/35/11/116005.
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      Effect of chelating agent concentration in alkaline Cu CMP process under the condition of different applied pressures

      doi: 10.1088/1674-4926/35/11/116005
      Funds:

      the Special Project Items NO.2 in National Long-Term Technology Development Plan, China 2009ZX02308

      the Hebei Natural Science Foundation of China E2013202247

      Project supported by the Special Project Items NO.2 in National Long-Term Technology Development Plan, China (No. 2009ZX02308) and the Hebei Natural Science Foundation of China (No. E2013202247)

      More Information
      • Corresponding author: Yuan Haobo, Email:237607378@qq.com
      • Received Date: 2014-04-09
      • Revised Date: 2014-05-20
      • Published Date: 2014-11-01

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