Planarization of Patterned Recording Media

The planarization of patterned recording media is essential to overcome the ¿flying height reduction¿ and ¿flying instability¿ of the head-slider. This paper reports two planarization techniques; one by compressing a morphological smooth surface onto a low glass transition temperature T_g/UV curable polymer/material coated patterned sample, while the other employs spin coating to coat patterned disks. A roughness of 0.3 nm was achieved by planarization using compression of smooth Si onto 35 K PMMA (heated above T_g to decrease its viscosity). It was also found that decreasing the spin speed from 5000 rpm to 1000 rpm improves the filling of grooves using spin coating of hydrogen silsesquioxane (HSQ) decreasing the height difference between the filled groove region and the land region from about 6 nm to 4 nm. Initial investigation using compression of smooth Si onto diluted HSQ also shows a decrease of roughness as dilution increases from 50.0% to 66.6%. Both techniques were applied in the planarization of a UV curable resist. The results show that about 1 nm is observed between the patterned and unpatterned regions using only spin coating. However, with compression using a flat mold, no height difference on average is observed.