Rapid evaluation of imprint quality using optical scatterometry

Optical scatterometry was used for the rapid and nondestructive testing of submicron and micron scale periodic patterns imprinted into the Shipley Microposit S1805 photoresist with the thickness of nearly 0.2 μm. Imprints were made using asymmetrical heating of imprint system and separation of the stamp without cooling cycle. Tests have showed that optimal conditions of imprint lithography with acceptable uniformity and repeatability are achieved when temperature is set to 120–130 °C, holding time is 60–90 s, and pressure is equal to 4 MPa. In the region of 100–110 °C imprint quality is poor because of the dominating elastic response of polymer layer. Rising of the temperature up to 140 °C leads to the noticeable liquefaction of the polymer. Thus, rapid separation of the mold and substrate cause certain damage of the imprinted grating.