This is a 2D cross-section rebuild of the UV nanoimprint lithography (UV-NIL) capillary-fill simulator. Instead of an isometric grid of trench boxes, three flat panels expose the same physics from complementary angles: a side-view slice of the trench row, a rise-vs-time chart comparing the simulated meniscus to the analytic Washburn law, and a capillary-number phase map swept over descent speed and viscosity.
Washburn equation (capillary rise):
L(t) = √( r·γ·cosθ / (2η) · t )
Capillary number (viscous vs. capillary forces):
Ca = η·v / γ
r is the trench half-width, γ the resist surface tension, θ the contact angle, η the viscosity, and v the mold's descent speed. Low Ca means capillary forces dominate: the meniscus in every trench has time to advance smoothly and air is pushed out ahead of it as the mold seats. High Ca means the mold seats faster than the meniscus can climb, so pockets of air get sealed in mid-trench and freeze there as bubble defects once the resist is UV-cured.
- Mold descent speed v — faster descent raises Ca and starves each trench of the time it needs to fill without trapping air.
- Resist viscosity η — a thicker resist raises Ca and slows the Washburn front, so runs are shown at a proportionally slower rate.
- Surface tension γ — a higher-γ resist lowers Ca and pulls the meniscus in faster, favoring complete, bubble-free filling.
- Contact angle θ — a larger θ shrinks cosθ, flattening the Washburn curve and slowing capillary rise even at fixed γ and η.
- The phase map colors every (v, η) combination by predicted defect probability at the current γ, with a crosshair marking the sliders' live position, so you can see how close a setting sits to the defect boundary before running it.
Real-world relevance: keeping Ca low (slow, controlled imprint speed and low-viscosity, UV-curable resists) is exactly why production UV-NIL tools imprint far more slowly than a naive "just press harder" approach — it is the single biggest lever for defect-free sub-10 nm replication.