Influence of Imprint Conditions on the Quality of Submicron Scale Imprinted Patterns

Abstract

Significance of imprint lithography as a high-throughput, low-cost means for the micro- and nanometer scale patterning of various substrates is expected to grow in the near future. Thus, investigations of the influence of imprint conditions on the quality of imprinted patterns are of great importance. If imprints are in the form of diffraction gratings, measurement of intensity of reflected light in selected diffraction orders may be used as an effective means for the fast and nondestructive evaluation of imprints. This method was used for the testing of submicron scale patterns imprinted into the Shipley Microposit S1805 photoresist with the thickness of nearly 0.2 μm. Tests have showed that optimal conditions of imprint are achieved when temperature is set to 120 – 130 °C, holding time is 60 – 90 seconds, and pressure is equal to 4 MPa. In the region of 100-110 °C imprint quality is very poor because of the dominating elastic response of polymer layer. Raising of the temperature up to 140 °C leads to the noticeable liquefaction of the polymer. Thus, rapid separation of the mold and substrate may cause certain damage of the imprinted grating.