Photopatterning process

With PSPIs, the photopatterning process involves significantly fewer process steps (Figure 19) and eliminates the need for expensive plasma equipment. However, the process is currently limited to aspect ratios of about 0.5 for negative features such as via holes. Higher aspect ratios can be obtained for positive features such as lines unfortunately, holes are the more-prevalent features for TFML structures. 

Figure 4. Photopattern process for wafer stage applied UV curable silicone coating.

Figure 19. Process steps for patterning polyimides by wet etching and dry etching and for direct photopatterning of a photosensitive polyimide. The abbreviation PR stands for photoresist.

Fig. 2 Atomic force microscopy (AFM) friction images and schematic illustrations of the patterning processes of a microcontact printed SAMs (mercaptoethanol dots in oc-tadecanethiol matrix, scale bar 10 xm) b patterned molecular printboards fabricated by supramolecular dip-pen nanolithography (DPN) (reprinted with permission from [92] Copyright 2004. WUey VCH) e locally hydrolyzed tert-butyl acrylate-terminated polymer film on oxidized silicon (soft lithography scale bar 3 xm) (Feng CL, Vancso GJ, SchOn-herr H, manuscript submitted to Langmuir) d photopatterned bilayer of diacetylene lipid (scale bar 10 xm). Reprinted in part with permission from [93], copyright (1999), American Chemical Society...

Suitable processing techniques for the formed hydrogels or solid biomaterials include gas foaming, stereolithography, photopatterning, and inkjet printing. 

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