SEMICONDUCTOR TECHNOLOGY

Effect of organic amine alkali and inorganic alkali on benzotriazole removal during post Cu-CMP cleaning

Liu Yang1, 2, Baimei Tan1, 2, , Yuling Liu1, 2, , Baohong Gao1, 2, Yilin Liu3, Chunyu Han1, 2, Qi Wang1, 2 and Siyu Tian1, 2

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 Corresponding author: Baimei Tan, bmtan@hebut.edu.cn; Yuling Liu, liuyl@jingling.com.cn

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Abstract: Benzotriazole (BTA), an anticorrosion agent of slurry, is the main organic pollutant remaining after CMP of multilayer copper wiring, and also the main removal object of post CMP cleaning. The adsorption of BTA onto the copper could form a dense Cu-BTA film, which makes the copper surface strongly passivated. According to this characteristic, quantitative analysis of BTA residue after cleaning is carried out by contact angle measurement and electrochemical measurement in this paper. A scanning electron microscope (SEM) with EDX was used to observe and analyze the BTA shape and elements. The efficiencies of organic alkali and inorganic alkali on the removal of BTA were studied. The corresponding reaction mechanism was also analyzed. The results show that the adsorption structure of Cu(I)-BTA cannot be destroyed in an alkaline environment with a pH less than 10; the effect of BTA removal by inorganic alkali is worse than that of the organic amine alkali with the coordination structure under the same pH environment; the FA/O II chelating agent with the fraction of 200 ppm can effectively remove BTA residue on the surface of copper wafer.

Key words: post CMP cleaningbenzotriazole (BTA)organic amine alkalielectrochemical measurement



[1]
Kwon T Y, Ramachandran M, Cho B J, et al. The impact of diamond conditioners on scratch formation during chemical mechanical planarization (CMP) of silicon dioxide. Tribology International, 2013, 67(4): 272
[2]
Zhang B G, Liu Y L, Wang C W. BTA free alkaline slurries developed for copper and barrier CMP. ECS J Solid State Sci Technol, 2015, 4(11): P5112
[3]
Sung I H, Hong J K, Chang D Y. First observation on the feasibility of scratch formation by pad-particle mixture in CMP process. Appl Surf Sci, 2012, 258(20): 8298 doi: 10.1016/j.apsusc.2012.05.044
[4]
Yeh C F, Hsiao C W, Lee W S. Novel post CMP cleaning using buffered HF solution and ozone water. Appl Surf Sci, 2003, 216(1): 46
[5]
Li Y L, Liu Y L, Wang C W, et al. Synergetic effect of chelating agent and nonionic surfactant for benzotriazole removal on post Cu-CMP cleaning. J Semicond, 2016, 37(8): 086001 doi: 10.1088/1674-4926/37/8/086001
[6]
Miao Y, Wang S, Wang C, et al. Effect of chelating agent on benzotriazole removal during post copper chemical mechanical polishing cleaning. Microelectron Eng, 2014, 130(C): 18
[7]
Otake A, Kuroda A, Matsumoto T. BTA removal and prevention of surface oxidation for copper post CMP cleaning. ICPT, 2009: 133
[8]
Gu Z B, Liu Y L, Gao B H, et al. Effect of the pH value in alkaline cleaning solution on benzotriazole removal. Micronanoelectron Technol, 2015, 52(12): 811
[9]
Chen Y, Xia M Z, Lei W, et al. Study on the corrosion inhibition properties of benzotriazole and its carboxyl alkyl derivatives. Material Protection, 2006, 39(7): 4
[10]
Mamas S, Kıyak T, Kabasakaloğlu M, et al. The effect of benzotriazole on brass corrosion. Mater Chem Phys, 2005, 93(1): 41 doi: 10.1016/j.matchemphys.2005.02.012
[11]
Hirabayashi H, Higuchi M. Copper-based metal polishing soXlution and method for manufacturing semiconductor device. US, US 5575885 A, 1996
[12]
Deng H W, Tan B M, Zhang Y, et al. Optimization of the roughness of GLSI multilayer Cu by FA/O alkaline cleaning solution. Electron Compon Mater, 2015, 34(10): 91
Fig. 1.  The adsorption structure of Cu(I)-BTA on Cu2O.

Fig. 2.  (Color online) Potential-pH diagram of copper water system[11].

Fig. 3.  (Color online) Change of corrosion current density caused by BTA contamination.

Fig. 5.  (Color online) Contact angles of Cu surface cleaned by different concentrations of alkalis.

Fig. 7.  (Color online) (a) The SEM picture and (b) EDX analysis of copper wafer after cleaning.

Fig. 6.  (Color online) (a) The SEM picture and (b) EDX analysis of copper wafer before cleaning.

Fig. 4.  (Color online) Electrochemical measurement results of the cleaning solutions based on four different alkalis. (a) KOH. (b) TMAH. (c) TEAH. (d) FA/O II.

Table 1.   Parameter setting of electrochemical workstation

Parameter OCP Tafel
Scanning scale (V) −1 to 1 OCP ± 0.3
Scanning time (s) 600
Scanning rate (10 mV/s) 10
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Table 2.   Effect of BTA removal on cleaning solutions based on four different alkalis.

Alkaline Mass fraction (ppm) pH Jcorr (10−7 A/cm2)
KOH 100 9.98 1.491
150 10.06 1.667
200 10.24 1.980
250 10.31 1.784
300 10.42 2.235
TMAH 100 9.92 1.890
150 10.36 4.103
200 10.43 4.226
250 10.50 5.422
300 10.56 5.762
TEAH 100 10.09 2.918
150 10.31 3.471
200 10.46 5.282
250 10.58 2.225
300 10.69 2.313
FA/O II 100 10.05 2.237
150 10.13 4.382
200 10.26 7.231
250 10.39 3.938
300 10.51 4.159
DownLoad: CSV
[1]
Kwon T Y, Ramachandran M, Cho B J, et al. The impact of diamond conditioners on scratch formation during chemical mechanical planarization (CMP) of silicon dioxide. Tribology International, 2013, 67(4): 272
[2]
Zhang B G, Liu Y L, Wang C W. BTA free alkaline slurries developed for copper and barrier CMP. ECS J Solid State Sci Technol, 2015, 4(11): P5112
[3]
Sung I H, Hong J K, Chang D Y. First observation on the feasibility of scratch formation by pad-particle mixture in CMP process. Appl Surf Sci, 2012, 258(20): 8298 doi: 10.1016/j.apsusc.2012.05.044
[4]
Yeh C F, Hsiao C W, Lee W S. Novel post CMP cleaning using buffered HF solution and ozone water. Appl Surf Sci, 2003, 216(1): 46
[5]
Li Y L, Liu Y L, Wang C W, et al. Synergetic effect of chelating agent and nonionic surfactant for benzotriazole removal on post Cu-CMP cleaning. J Semicond, 2016, 37(8): 086001 doi: 10.1088/1674-4926/37/8/086001
[6]
Miao Y, Wang S, Wang C, et al. Effect of chelating agent on benzotriazole removal during post copper chemical mechanical polishing cleaning. Microelectron Eng, 2014, 130(C): 18
[7]
Otake A, Kuroda A, Matsumoto T. BTA removal and prevention of surface oxidation for copper post CMP cleaning. ICPT, 2009: 133
[8]
Gu Z B, Liu Y L, Gao B H, et al. Effect of the pH value in alkaline cleaning solution on benzotriazole removal. Micronanoelectron Technol, 2015, 52(12): 811
[9]
Chen Y, Xia M Z, Lei W, et al. Study on the corrosion inhibition properties of benzotriazole and its carboxyl alkyl derivatives. Material Protection, 2006, 39(7): 4
[10]
Mamas S, Kıyak T, Kabasakaloğlu M, et al. The effect of benzotriazole on brass corrosion. Mater Chem Phys, 2005, 93(1): 41 doi: 10.1016/j.matchemphys.2005.02.012
[11]
Hirabayashi H, Higuchi M. Copper-based metal polishing soXlution and method for manufacturing semiconductor device. US, US 5575885 A, 1996
[12]
Deng H W, Tan B M, Zhang Y, et al. Optimization of the roughness of GLSI multilayer Cu by FA/O alkaline cleaning solution. Electron Compon Mater, 2015, 34(10): 91
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    Received: 28 June 2018 Revised: 01 September 2018 Online: Uncorrected proof: 11 October 2018Published: 13 December 2018

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      Liu Yang, Baimei Tan, Yuling Liu, Baohong Gao, Yilin Liu, Chunyu Han, Qi Wang, Siyu Tian. Effect of organic amine alkali and inorganic alkali on benzotriazole removal during post Cu-CMP cleaning[J]. Journal of Semiconductors, 2018, 39(12): 126003. doi: 10.1088/1674-4926/39/12/126003 L Yang, B M Tan, Y L Liu, B H Gao, Y L Liu, C Y Han, Q Wang, S Y Tian, Effect of organic amine alkali and inorganic alkali on benzotriazole removal during post Cu-CMP cleaning[J]. J. Semicond., 2018, 39(12): 126003. doi: 10.1088/1674-4926/39/12/126003.Export: BibTex EndNote
      Citation:
      Liu Yang, Baimei Tan, Yuling Liu, Baohong Gao, Yilin Liu, Chunyu Han, Qi Wang, Siyu Tian. Effect of organic amine alkali and inorganic alkali on benzotriazole removal during post Cu-CMP cleaning[J]. Journal of Semiconductors, 2018, 39(12): 126003. doi: 10.1088/1674-4926/39/12/126003

      L Yang, B M Tan, Y L Liu, B H Gao, Y L Liu, C Y Han, Q Wang, S Y Tian, Effect of organic amine alkali and inorganic alkali on benzotriazole removal during post Cu-CMP cleaning[J]. J. Semicond., 2018, 39(12): 126003. doi: 10.1088/1674-4926/39/12/126003.
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      Effect of organic amine alkali and inorganic alkali on benzotriazole removal during post Cu-CMP cleaning

      doi: 10.1088/1674-4926/39/12/126003
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      Project supported by the Major National Science and Technology Special Projects (No. 2016ZX02301003-004-007), the Natural Science Foundation, China (No. 61704046), and the Hebei Natural Science Foundation Project (No. F2018202174).

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