2.5D surface patterning with two-photon lithography

Surface topographies influence how a material or device interacts with liquids, particles, light, and biological cells. Surface patterning creates micro- and nanoscale topographies that can tune wettability, adhesion, optical response, or cell behavior. In surface engineering, precisely fabricating these structures provides an additional design parameter for controlling such interactions beyond the properties of an unpatterned surface.

Turning micro- and nanoscale topography into surface function

From 2.5D reliefs to hierarchical textures, surface geometry can influence wettability and fluid transport, particle adhesion, optical response, and cell migration. Combined with surface chemistry, it provides a second design parameter in surface engineering for controlling behavior and functions such as superhydrophobicity and self-cleaning, contamination control, optical beam shaping, and defined cell-surface interactions. In surface engineering, biomimetic designs offer useful starting points, but their function depends on accurately reproducing feature size, height, curvature, and hierarchy. Nanoscribe’s Two-Photon Grayscale Lithography (2GL^®) fabricates surface topographies with high precision and throughput and supports rapid design iteration as well as master fabrication for replication.

High-precision grayscale lithography for functional surfaces

2GL^® combines additive fabrication with ready-to-use negative-tone resins to directly transform digital models into 2.5D surface patterns. These structures can be used as prototypes for functional testing or as master templates for replication.

• Rapid, maskless 2.5D surface patterning: 2GL^® processes digital grayscale designs with more than 4,000 exposure levels to fabricate complex surface topographies, enabling fast design changes without photomasks.  

• High shape and surface quality: Shape accuracy down to ≤ 200 nm and surface roughness down to R_a ≤ 5 nm support precisely defined surface patterns for surface engineering applications.

• Tall topographies with simplified processing: 2GL^® combined with aberration-free Dip-in Laser Lithography and photoresins enables structures up to 1,000 µm in height. Ready-to-use negative-tone photoresins typically save you from cumbersome and error-prone processes including spin-coating and pre- and post-baking and are insensitive to environmental and development conditions. 

• Wide range of compatible substrates: 2GL^® supports transparent, opaque, conductive and non-conductive substrates, including glass, silicon, and prepatterned wafers.

• Consistent topographies across large areas: For large-area surface patterning, automatic tilt compensation corrects substrate tilt to reduce height deviations and tilt-induced staircase effects, while 2GL® printing strategy minimizes visible stitching between writing fields.

• Tailored materials for direct use: Nanoscribe’s photoresins offer material properties suitable for directly using printed surface patterns as final structures, eliminating the need for additional pattern-transfer processes such as etching. 

• From prototype to replication master: 2GL^® fabricates surface patterns for functional testing and design iteration. The 2GL^® technology can also produce master templates for nanoimprint lithography (NIL), hot embossing or micro injection molding.  

• Demonstrated replication workflows: 2GL^® master templates have been used in replication workflows with specialist partners, including EV Group for NIL, kdg opticomp GmbH for micro injection molding, and Microworks GmbH for electroforming, considering the specific downstream processing steps for each replication method.