Parameter study to find best speeds of fabrication that can be achieved along different directions (a) shows the distribution of laser power along the voxel, the power density is higher along the Z axis than along the X and Y axes. (b) Optimization of scan speeds along X, Y and XY directions. The numbers next to lines give scan speeds at nm/ms or µm/s; (c) shows optimum structures along X, Y and XY directions their scan speeds and dimensions. (d)-(e) shows pillar structures fabricated along Z direction, the pillars are all collapsed during post fabrication development due to forces of viscosity from the developing solvents, but their dimensions can be measured well from SEM measurements. The adaptation of the longitudinal scanning scheme allows faster fabrication of array structures constituting taller hexahedral unit cells. The fabrication of 3D structures constitutes the laser scanning along X, Y, XY and Z directions. Due to many scanning paths the threshold speed for fabrication of 3D structures can be higher than fabricating 2D structures. This is because of the high relative density of laser powers deposited in a three-dimensional area during fabrication of 3D structure. We proposed a fabrication window based on the study of scanning parameter along the vertical direction. The scanning window provides parameters for optimum fabrication conditions of structures with heights up to 20 µm at a scanning speed of 14 µm/s (14 nm/ms) at different laser powers. The fabrication window is depicted in Figure 9. This fabrication window can be used to select fabrication parameters for various structures.

Contexts in source publication

Context 1

... distribution of laser intensity around the laser focus and the shape of the voxel formed can be seen in Figure 8 . Results from scan speed test along Z-direction is summarized in Figure 8(d-e). ...

Context 2

... distribution of laser intensity around the laser focus and the shape of the voxel formed can be seen in Figure 8 . Results from scan speed test along Z-direction is summarized in Figure 8(d-e). The variable distribution of laser power at the focus of the laser can be seen in Figure 8(a). ...

Context 3

... from scan speed test along Z-direction is summarized in Figure 8(d-e). The variable distribution of laser power at the focus of the laser can be seen in Figure 8(a). A higher density of laser power is distributed along the vertical direction (direction of propagation of laser) than the horizontal direction. ...

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... terms of fabrication this means that the useful structures can be fabricated at a faster rate in the vertical direction. Vertical pillars were fabricated by scanning along Z-axis in Figure 8(d), but the polymeri is not mechanically strong enough to stand by itself after developing. Still well-formed structures can be fabricated at a scan speed of around 10 nm/ms. ...