(Color online) AFM-image of the FIB deposited SiO2 on NIL-master after imprinting. Before imprinting, the highest feature was measured to be in height. The smallest feature was 270 nm in height.
(Color online) Transmittance of the deposited SiO2 at a wavelength between 340 and 342 nm. (a) Optical microscope image showing the location of the transmittance line-scan. (b) and (c) measured transmittance along the lines indicated in (a). The transmittance of the highest pattern was reduced to 2.3%, while the smallest feature still permitted 49% of the light to pass.
(Color online) Impact of the height of deposited SiO2 on the transmissivity. The transmissivity follows the Beer–Lambert law [Eq. (1) ] with an attenuation coefficient .
(Color online) Impact of the UV-dose on the imprint topography. AFM images of the imprints utilizing the stamp shown in Fig. 1 at UV exposure doses of (a) 160, (b) 300, (c) 1000, and (d) . The UV dose recommended by the resist manufacturer is . The imprint performed with an UV-dose of is clearly distorted. Although the structure-fidelity was partly unsatisfactory the demolding process still worked flawless in all cases.
(Color online) Magnified view of Figs. 4(a) and 4(d) . The ideally flat surface of the imprinted trench is clearly distorted in case of a UV-dose of 160 (a), (c), and below. In fact, the center of the trench (marked by “Center”) appears deeper than the edge “Edge.” For the higher UV-dose of 6000 (b), (d), this effect is not visible.
Height profile in single areas of the imprints shown in Fig. 4 . The deformation previously not visible becomes visible even for the imprint of the smallest pattern with an UV-dose of . This pattern is overexposed by a factor of at least 4. The height is visualized by a periodic black–white gradient having a period of 30 nm.
(Color online) Illustration of the fitting process. A cross section (b) through the imprinted feature is obtained from the AFM data (a). Along the cross-section on four position the milled fine-structure [double cross in (a)] is intersecting. Thus, this FIB milled fine structure is removed from the data-set and the data are fitted to Eq. (2) , resulting in the fit-factors x 0, y 0, and a. The curve resulting from the fit perfectly matches the original data.
(Color online) Impact of the resist UV exposure dose d resist on thebowing of the imprints. The bowing factor a follows Eq. (3) with and m.
(Color online) Harmonix AFM phase image of the imprinted area marked in Fig. 4(b) . The imprint was exposed to a UV-dose of . The phase image maps the mechanical properties of the material surface. The image shows that even for area exhibiting significant bowing the material properties are homogeneous.
Chemical composition of FIB deposited SiO2 obtained by various researchers. When multiple results were shown only the purest SiO2 deposition is given.
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