AVS 62nd International Symposium & Exhibition
    Thin Film Friday Sessions
       Session TF+MI-FrM

Paper TF+MI-FrM10
A Comparison of Heptane Solvent Annealing versus Thermal Annealing Block Copolymers for Bit Patterned Advanced Media

Friday, October 23, 2015, 11:20 am, Room 111

Session: Thin Films for Light Trapping, Plasmonic, and Magnetic Applications
Presenter: Allen Owen, University of Alabama
Authors: A. Owen, University of Alabama
A. Montgomery, University of Alabama
H. Su, University of Alabama
S. Gupta, University of Alabama
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Hard disk drive storage media is trending towards both smaller physical size and greater storage capacity by increasing the areal density of the magnetic storage media. Bit patterning shows potential as a method for increasing this areal density. A block copolymer template can be used to provide an etch mask for bit patterning a magnetic thin film. Statistical designs of experiments were carried out comparing the effect of nanopatterning via ion milling Co/Pd multilayers using two different annealing methods for PS-PFS block copolymers. The design of experiments for each annealing method varied the etch angle, etch time and etch power during ion milling. Wafers that were sputter-deposited with Co/Pd multilayered thin films were spin-coated with PFS block copolymer and solvent annealed under heptane vapor in an oil bath at 35 °C for 6 hours. Identical wafers were thermally annealed in atmosphere at 140 °C for 48 hours. After annealing, the films were ashed in oxygen to remove the PS, leaving the PFS spheres as masks for the subsequent ion milling. The results from each annealing study showed that nanopillars with a nominal size of ~ 30 nm have been fabricated. The thermally annealed Co/Pd multilayers yielded a 407% increase in coercivity to ~6.6 kOe, while the heptane annealed thin film resulted in a 223% increase to ~4.2 kOe. A statistical design of experiments comparing two different etch techniques:(i) inductively coupled plasma reactive ion etching (ICP-RIE) and (ii) ion milling was carried out for these two annealing methods. The results indicate that process optimization can be achieved with a combination of the correct annealing and etching techniques.