UV-nanoimprint with the assistance of gas condensation at atmospheric environmental pressure

Nanoimprint should be carried out in an ordinary environment from the standpoint of cost-performance. However, bubble defects arise when the process is done in air and the problem can become worse with large patterns and thin resin films. UV-nanoimprint using resin droplets reduces air capture by expelling air during resin spreading and, in some cases, achieves bubble free UV-nanoimprint by air dissolution in resin. When the authors simulated the smooth spreading of a large resin droplet in wafer warping, resin spreading occurred on mold plateaus but hardly reached into mold recesses where a significant amount of air was sealed and the air in a mold recess was not completely dissolved in resin within 10 min under an imprint pressure of 0.5 MPa. In contrast, a captured gas of concentrated pentafluoropropane (CHF2CH2CF3, 1,1,1,3,3-pentafluoropropane, HFC-245fa, CAS No. 460-3-1) whose vapor pressure is 0.15 MPa at room temperature was completely condensed and dissolved within 2 s, leaving no trace of bubble ...