Study of air bubble generation and its minimization during dispensing based ultraviolet nanoimprint lithography (UV-NIL)

• Bubble trapping in dispensing based UV-NIL is numerically analyzed.
• The imprinting velocity is a key parameter to decrease the air bubble volume.
• Contact angle, polymer thickness and aspect ratio also affect bubble trapping.
• NIL experiments are carried out to compare the numerical results.
• More polymers are filled with the cavity at higher pressure.

Air bubble trapping characteristics in the cavity are numerically analyzed in dispensing based ultraviolet – nanoimprint lithography (UV-NIL). This air trapping mechanism in the cavity is investigated by numerical method based on a squeeze model. Air bubble volume in the stamp cavity is calculated for various imprinting velocities, contact angles, polymer thicknesses, and aspect ratios in order to find out how to reduce trapped air. Predicted results show that imprinting velocity is a key parameter reducing the air bubble volume. Contact angles between stamp, substrate, and polymer also affect the reduction of air bubble. However, a different tendency is observed with the polymer thickness at each aspect ratio against our expectations.

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