Fig. 1. Sectional view of the Si wafer attached to an SEM pin for processing.

Fig. 2. The setups for the two employed ambient media. Setup (a) was used for processing in air and setup (b) for processing in fluid ambient media. The latter has an additional plate capacitor to monitor the fluid level.

Fig. 3. Schematic showing the rotation of the laser scanning raster used to create more homogeneous structures.

Fig. 4. Si target structured in isopropanol with 1400 pulses at a fluence of $5.7~\text{kJ}/\text{m}^{2}$ viewed from above with a 1500 $\times$ magnification.

Fig. 5. Comparison of the structure shapes resulting from different ambient media. The structures in the left column (images (a) and (c)) were created in air ($8.6~\text{kJ}/\text{m}^{2}$, 450 pulses) whereas the cones displayed in the right column (images (b) and (d)) were generated in isopropanol ($5.7~\text{kJ}/\text{m}^{2}$, 1400 pulses). The top row (images (a) and (b)) is viewed from above ($0^{\circ }$) while the bottom row (images (c) and (d)) is viewed from the side ($45^{\circ }$).

Fig. 6. Sketch of the target buildup defining the three basic dimensions $d$, $b$ and $s$, describing the cone distance, the base and the structure height, respectively.

Fig. 7. Si wafers processed in liquid isopropanol from an approximate $90^{\circ }$ degree side view. The number of pulses were (a) 700, (b) 1400, (c) 1750 and (d) 2100 respectively, with a constant rotation angle of $\unicode[STIX]{x1D6E5}\unicode[STIX]{x1D6FC}=45^{\circ }$. The laser fluence of $5.7~\text{kJ}/\text{m}^{2}$ was kept the same.

Fig. 8. Correlation of remaining substrate thickness $b$ and structure height $s$ for different numbers of pulses. The laser fluence of $5.7~\text{kJ}/\text{m}^{2}$ and the rotation angle of $\unicode[STIX]{x1D6E5}\unicode[STIX]{x1D6FC}=45^{\circ }$ were kept constant, as well as the ambient medium, which was isopropanol in all cases.