To optimize the existing slurry for abrasive-free polishing (AFP) of hard disk substrate, a water-soluble free radical initiator, 2, 20-azobis [2-(2-imidazolin-2-yl) propane] dihydrochloride (AIBI) is introduced to the H2O2-based slurry. The polishing results show that, the material removal rate (MRR) of hard disk substrate polished with H2O2-based slurry containing AIBI is obviously higher than that without AIBI. The acting mechanism of the improved MRR is investigated. Electron paramagnetic resonances tests show that, by comparison with H2O2 slurry, H2O2-AIBI slurry provides higher concentration of hydroxyl radicals. Auger electron spectrometer analyses further demonstrate that the oxidation ability of H2O2-AIBI slurry is much greater than H2O2 slurry. In addition, potentiodynamic polarization tests show that the corrosion dissolution rate of hard disk substrate in H2O2-AIBI slurry is increased. Therefore that stronger oxidation ability and a higher corrosion dissolution rate of H2O2-AIBI slurry lead to higher MRR can be concluded.
REN Xiao-yan, LEI Hong, CHEN Ru-ling, CHEN Yi
. Effect of AIBI as Free Radical Initiator on Abrasive-Free Polishing of Hard Disk Substrate[J]. Journal of Shanghai University, 2014
, 20(6)
: 680
-688
.
DOI: 10.3969/j.issn.1007-2861.2014.04.007
[1] Ali I, Roy S, Shinn G. Chemical mechanical polishing of interlayer dielectric: a review [J].
Solid State Technol, 1994, 37(10): 63-70.
[2] Bukkapatnam S T S, Rao P K, LihWC, et al. Process characterization and statistical analysis
of oxide CMP on a silicon wafer with sparse data [J]. Appl Phys, 2007, A88: 785-792.
[3] Lei H, Luo J B. CMP of hard disk substrate using colloidal SiO2 slurry: preliminary experimental
investigation [J]. Wear, 2004, 257(5/6): 461-470.
[4] Qi Z Q, Lee W M. XPS study of CMP mechanisms of NiP coating for hard disk drive
substrates [J]. Tribol Int, 2010, 43: 810-814.
[5] PatrickWJ, GuthrieWL, Standley C L, et al. Application of chemical mechanical polishing
to the fabrication of VLSI circuit interconnections [J]. J Electrochem Soc, 1991, 138(6): 1778-
1784.
[6] Nguyen V H, Hof A J, Kranenburg H V, et al. Copper chemical mechanical polishing using
a slurry-free technique [J]. Microelectron Eng, 2001, 55(1/4): 305-312.
[7] van der Velden P. Chemical mechanical polishing with fixed abrasives using different subpads
to optimize wafer uniformity [J]. Microelectron Eng, 2000, 50(1/4): 41-46.
[8] Hayashi Y, Kikuta K, Kikkawa T. A new abrasive-free, chemical mechanical polishing technique
for aluminum metallization of ULSI devices [C]// Proceedings of International Electron
Devices Meeting (IEDM). 1992: 976-978.
[9] Wang Z J, Lei H, Zhang W T, et al. Cu (II) as a catalyst for hydrogen peroxide system
abrasive-free polishing on hard disk substrate [J]. Key Eng Mater, 2013, 562/565: 91-95.
[10] Zhang W T, Lei H. Abrasive-free polishing of hard disk substrate with H2O2-K2S2O8-NaHSO3
slurry [J]. Adv Mater Res, 2013, 690/693: 3209-3212.
[11] ZhangWT, Lei H. Abrasive-free polishing of hard disk substrate with H2O2-C4H10O2-Na2S2O5
slurry [J]. Friction, 2013, 1(4): 359-366.
[12] Costa C, Santos V H S, Araujo P H H, et al. Rapid decomposition of a cationic azo-initiator
under microwave irradiation [J]. J Appl Polym Sci, 2010, 118(3): 1421-1429.
[13] Czech Z, Butwin A, Herko E, et al. Novel azo-peresters radical initiators used for the synthesis
of acrylic pressure-sensitive adhesives [J]. Express Polymer Letters, 2008, 2(4): 277-283.
[14] Demirci S, Caykara T. Controlled grafting of cationic poly [(ar-vinylbenzyl) trimethylammonium
chloride] on hydrogen-terminated silicon substrate by surface-initiated RAFT polymerization
[J]. React Funct Polym, 2012, 72(9): 588-595.
[15] Hariharaputhiran M, Zhang J, Ramarajan S, et al. Hydroxyl radical formation in H2O2-
amino acid mixtures and chemical mechanical polishing of Copper [J]. J Electrochem Soc, 2000,
147(10): 3820-3826.
[16] Lu J, Garland J E, Pettit C M, et al. Relative role of H2O2 and glycine in CMP of copper
studied with impedance spectroscopy [J]. J Electrochem Soc, 2004, 151(10): 717-722.
[17] Kang M C, Nam H S, Won H Y, et al. Effects of OH radicals on formation of Cu oxide and
polishing performance in Cu chemical mechanical polishing [J]. Electrochem Solid-State Lett,
2008, 11(2): 32-35.
[18] Peddeti S, Ong P, Leunissen L H A, et al. Chemical mechanical polishing of Ge using colloidal
silica particles and H2O2 [J]. Electrochem Solid-State Lett, 2011, 14(7): 254-257.
[19] Lei H. Properties of surface oxidation film in CMP of computer hard disk substrate [J]. Chin J
Inorg Chem, 2009, 25(2): 206-212.
[20] Li J, Liu Y H, Pan Y, et al. Chemical roles on Cu-slurry interface during copper chemical
mechanical planarization [J]. Appl Surf Sci, 2014, 293: 287-292.
