Ultraviolet exposure selectively changes the SU-8 layer by crosslinking the regions reached through the mask. During development, the unexposed material is removed while the crosslinked regions remain attached to the substrate as raised structures. This conversion from a patterned resist layer to a stable relief provides the fixed geometry required for microscale replication.
The mask determines which parts of the SU-8-coated substrate receive ultraviolet light, so its pattern establishes the locations of the future raised features. Development then reveals that pattern by removing unexposed material. Together, selective exposure and development transform the mask design into a physical master that can guide subsequent device fabrication.
A durable master can support replication of microscale structures rather than serving only as a one-time patterned surface. Its stable relief preserves the intended channel or feature geometry when researchers mold elastomers such as PDMS. This repeatable geometry is valuable when biological experiments require consistently shaped devices for controlled flow, cell positioning, or tissue-engineering studies.
Preparation begins by coating a substrate with SU-8, exposing selected regions through a mask, and developing the layer to remove unexposed material. The resulting raised relief serves as the patterned form for molding an elastomer. This workflow converts a lithographic design into a physical structure that can be used to create microscale biological devices.
Researchers place an elastomer such as PDMS against the patterned master so the master’s raised features define the resulting microscale structure. The replicated geometry can form microfluidic channels or related device features. Because the master preserves precise dimensions, the molded structure can support controlled fluid flow and organized cell-based experiments.
SU-8 masters support fabrication of lab-on-a-chip systems, cell culture devices, and tissue-engineering platforms. Their precise microscale geometry helps researchers direct fluid movement, position cells, and establish controlled experimental environments. These capabilities make the masters useful as a foundation for studying biological processes and designing bioengineering systems that require spatial control.