Figure 4.
SEM images of the inclined sacrificial post under different exposure conditions. The height of the photoresist post was 20 μm, and the pattern of the photomask was a circle with a diameter of 50 μm. (a) A 160 μm PET film was placed between the wafer and photomask, and the exposure time was 14 s at 25 mW/cm2. The angle of the resulting post was 50°, obtained by averaging 9 individual posts from five rounds of fabrication. (b) The same PET film was used, with an exposure time of 14 s. The measured angle was 63°. (c) Soft contact was used, the exposure time was 14 s, and the angle was 72°. (d) Hard contact was used, the exposure time was 14 s, and the angle was 83°.