SEMICONDUCTOR TECHNOLOGY

Synergic effect of chelating agent and oxidant on chemical mechanical planarization

Weijuan Liu and Yuling Liu

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 Corresponding author: Weijuan Liu, E-mail: lwjcpf@163.com

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Abstract: Chemically dominant alkaline slurry, which is free of BTA (benzotriazole) and other inhibitors, was investigated. The synergic effect of the chelating agent and oxidant on the chemical mechanical planarization (CMP) was taken into consideration. Copper CMP slurry is mainly composed of an oxidizer, nonionic surfactant, chelating agent and abrasive particles. The effect of different synergic ratios of oxidant with chelating agent on the polishing removal rate, static etch rate and planarization were detected. The planarization results reveal that with the increase of oxidant concentration, the dishing value firstly diminished and then increased again. When the synergic ratios is 3, the dishing increases the least. A theoretical model combined with chemical-mechanical kinetics process was proposed in the investigation, which can explain this phenomenon. Based on the theoretical model, the effect of synergic ratios of oxidant with chelating agent on velocity D-value (convex removal rate minus recessed removal rate) was analyzed. The results illustrate that when the synergic ratio is between 2.5—3.5, the velocity D-value is relatively higher, thereby good planarization can be achieved in this interval. This investigation provides a new guide to analyze and study copper line corrosion in the recessed region during copper clearing polishing.

Key words: CMPtheoretical modelsynergic ratiosdishingstatic etch rates



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Fig. 1.  (a) The effect of synergic ratios of oxidant with chelating agent on polishing removal rate and static etch rate. (b) The D-value of polishing removal rate and static etch rate with different synergic ratios.

Fig. 2.  The electron microscope diagram of TM2 pattern wafer before and after over-polishing.

Fig. 3.  (Color online) Effect of different synergic ratios on planarization.

Fig. 4.  The synergic effect of oxidant and chelating agent on the polishing process control schematic.

Table 1.   The process conditions of CMP.

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    Received: 22 June 2014 Revised: Online: Published: 01 February 2015

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      Weijuan Liu, Yuling Liu. Synergic effect of chelating agent and oxidant on chemical mechanical planarization[J]. Journal of Semiconductors, 2015, 36(2): 026001. doi: 10.1088/1674-4926/36/2/026001 W J Liu, Y L Liu. Synergic effect of chelating agent and oxidant on chemical mechanical planarization[J]. J. Semicond., 2015, 36(2): 026001. doi: 10.1088/1674-4926/36/2/026001.Export: BibTex EndNote
      Citation:
      Weijuan Liu, Yuling Liu. Synergic effect of chelating agent and oxidant on chemical mechanical planarization[J]. Journal of Semiconductors, 2015, 36(2): 026001. doi: 10.1088/1674-4926/36/2/026001

      W J Liu, Y L Liu. Synergic effect of chelating agent and oxidant on chemical mechanical planarization[J]. J. Semicond., 2015, 36(2): 026001. doi: 10.1088/1674-4926/36/2/026001.
      Export: BibTex EndNote

      Synergic effect of chelating agent and oxidant on chemical mechanical planarization

      doi: 10.1088/1674-4926/36/2/026001
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      Project supported by the Natural Science Foundation of Hebei Province, China (Nos. E2013202247, E2014202147) and the Department of Education-Funded Research Projects of Hebei Province, China (No. QN2014208).

      More Information
      • Corresponding author: E-mail: lwjcpf@163.com
      • Received Date: 2014-06-22
      • Accepted Date: 2014-09-22
      • Published Date: 2015-01-25

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