The developed pattern depends on whether illuminated or unilluminated photoresist regions are selectively removed. This choice determines which portions of the substrate remain covered by resist and which become exposed for later processing. As a result, the same exposure strategy can support different surface geometries, depending on how the resist responds during development.
The photomask carries the designed image that guides where light reaches the photoresist. Its pattern therefore establishes the spatial arrangement of the features transferred to the substrate. Accurate image transfer is especially important when fabricating micro- and nanoscale structures for biological systems, where surface geometry can influence cell positioning and interactions.
Development creates a resist-defined template, but etching or deposition gives that template a more durable physical form. Etching can shape exposed substrate regions, whereas deposition can add material where the patterned surface permits it. These follow-up steps convert a temporary light-defined pattern into structures suitable for channels, substrates, sensors, or other biological devices.
A typical workflow begins by coating a substrate with photoresist, exposing it through a photomask, and developing the surface so selected regions are removed. The resulting pattern then guides etching or deposition. Each stage has a distinct function: coating provides light sensitivity, exposure transfers the image, development reveals it, and later processing establishes the final structure.
In microfluidic fabrication, patterned regions define the geometry of channels and related structures on a substrate. These features provide controlled spaces for fluid handling and can be integrated with biological experiments. The technique is useful because its spatial precision supports devices that organize microscale environments for lab-on-a-chip studies and cellular analysis.
Photolithography can produce patterned cell-culture substrates and surfaces that control where cells position themselves and how they interact with their surroundings. Researchers can therefore examine cellular responses within defined physical architectures rather than on uniformly shaped surfaces. This capability supports tissue engineering, biosensor development, and investigations of cell behavior in engineered microenvironments.