Electron beam lithography for magnetic recording heads: Characterization and optimization of critical components

Electron beam lithography has been implemented with a chemically amplified negative tone NEB-31 resist to fabricate the write top pole and read sensors for magnetic recording. To better understand the proximity effect and optimize these two critical components in electron beam patterning, Monte Carlo simulation with SELID software has been employed to characterize the energy distribution of the write top pole structure and simulate the resist profile in the break point (BP) region. To obtain a sharp BP angle and a pole area that has a uniform and narrow pole width, the authors have optimized the computer-aided design and the yoke/pole dose ratios based on their simulation results. The authors have also experimentally verified these results with NEB-31 resist. In addition, the electron backscattering effect from the relevant metallic underlayers, such as NiFe and Ta of varying thickness on the top pole critical dimension as a function of BP angle was simulated and analyzed. Experiments were conducted to ve...