Reduction of non-fill defects in nanoimprint lithography

Field-by-field-type UV nanoimprint lithography equipped with an on-demand inkjet dispense system, known as jet and flash imprint lithography (JFIL), has been developed. In JFIL, the inkjet resist drops still remain independent of each other when imprinting a mold, so that the ambient gas is trapped among the resist drops to generate bubbles. It takes time for the trapped bubbles to disappear, and the bubbles sometimes remain in the cured resist film to cause open defects. The waiting time for the disappearance of the gas results in low throughput and the remaining bubbles cause defect problems in JFIL. The fast disappearance of trapped bubbles was demonstrated in the case when carbon dioxide gas was used as the ambient gas. On the basis of fluid mechanics, combined-drop JFIL and its resist material was developed, in which the resist drops were combined with each other prior to imprinting to minimize trapped gas volume.