SU-8 2025 process recipe

Spin coating

SU-8 2025 is spin-coated to 21.7–79.2 µm. The curve below is redrawn from the manufacturer's published data — read your target thickness off the vertical axis and take the matching spin speed as a starting point.

Recommended program (same for all grades in this document): dispense 1 ml of resist per inch (25 mm) of substrate diameter; spin at 500 rpm for 5-10 s at 100 rpm/s acceleration, then spin at the target speed (per Figure 1) for 30 s at 300 rpm/s acceleration. Edge bead removal (EBR) with MicroChem's EBR PG solvent stream at the wafer edge is recommended before soft bake, both to limit hotplate contamination and to let the photomask reach close contact with the wafer. Source: "Coat" / "Recommended Program" / "Edge Bead Removal (EBR)", p.2.

Soft bake

Soft bake

Not published — characterize on-tool

Notes

Published only as a THICKNESS-BINNED table shared by all four grades covered in this document (SU-8 2025/2035/2050/2075), not a single value per grade: 25-40 µm → 0-3 min @65°C then 5-6 min @95°C; 45-80 µm → 0-3 min @65°C then 6-9 min @95°C; 85-110 µm → 5 min @65°C then 10-20 min @95°C; 115-150 µm → 5 min @65°C then 20-30 min @95°C; 160-225 µm → 7 min @65°C then 30-45 min @95°C. SU-8 2025's own spin curve spans roughly 22-80 µm (1000-4000 rpm), i.e. mostly the 25-40 and 45-80 µm bins. Convection ovens are explicitly not recommended (can skin over and trap solvent). A cool-down/re-heat 'wrinkle' check is described to confirm the film is fully dry.Show more

SOURCE: Table 2 "Soft Bake Times", p.2 of the MicroChem SU-8 2000 (2025-2075) Processing Guidelines

Exposure dose

The manufacturer does not publish a clearing dose for SU-8 2025. Determine it with a dose array on your own tool.

As published

"SU-8 2000 photoresist is most commonly exposed with conventional UV (350-400 nm) radiation, although i-line (365 nm) is the recommended wavelength. SU-8 2000 may also be exposed with e-beam or x-ray radiation." (Processing Guidelines, p.1). The dose table itself (Table 3) is not separately re-attributed to a specific wavelength beyond this general statement.Show more

Not published for this resist: Dose at 365 nm, Dose at 405 nm — characterize on-tool.

Development

Developer

SU-8 Developer (MicroChem)

Method

immersion

Rinse

IPA

Developer family

Solvent

Not published for this resist: Dilution, Time — characterize on-tool.

SOURCE: "Development" and "Rinse and Dry" sections plus Table 6 "Development Times for SU-8 Developer", p.3-4

Hard bake, etch & strip

Stripper

MicroChem Remover PG swells and lifts only minimally cross-linked SU-8 2000. A fully cured/hard-baked film cannot be removed with Remover PG alone — it requires an OmniCoat (30-100 nm) sacrificial underlayer (heat Remover PG to 50-80°C, immerse 30-90 min) or an oxidizing strip (piranha etch, plasma ash, RIE, laser ablation, or pyrolysis). RIE recipe given: 200 W, 80 sccm O2, 8 sccm CF4, 100 mTorr, 10°C. Source: "Removal" / "Plasma Removal", p.5.Show more

Storage

Store upright in tightly closed containers, cool and dry, away from direct sunlight, at 40-70°F (4-21°C); away from light, acids, heat, and ignition sources. Shelf life is twelve months from date of manufacture. Source: "Storage", p.5.Show more

Not published for this resist: Hard bake, Descum, Etch resistance — characterize on-tool.

SOURCE: "Hard Bake (cure)" section, p.4

Where it's used

SU-8 2025 is the lowest-viscosity grade covered by this processing document (4500 cSt vs. up to 22,000 cSt for SU-8 2075) and spin-coats to roughly 20-80 µm depending on speed. Pick 2025 when your target film sits in the low tens of microns and you want the shortest bakes and best feature fidelity the 2000 family offers at that thickness; step up to SU-8 2050 or 2100 for progressively thicker single coats. Like every SU-8 2000 grade, it cross-links in two stages — exposure generates acid, and the post-exposure bake thermally drives the epoxy cross-linking — so PEB is a required processing step, not an optional cure. Soft-bake, PEB, dose and develop times are published only as thickness-binned ranges shared across the whole 2025-2075 family; treat the low end of the matching bin as a starting point and use the datasheet's cool-down/re-heat 'wrinkle' test to confirm the soft bake is complete. Once fully cross-linked, SU-8 is notoriously hard to strip: plain solvent remover only works on minimally exposed/baked film, and a hard-baked structure needs either a sacrificial OmniCoat layer beneath it or an oxidizing strip (piranha, plasma ash, RIE, laser ablation, pyrolysis) to remove. Edge bead removal before soft bake is recommended for every grade in this series to keep the photomask in close contact with the wafer and preserve resolution and aspect ratio in thick films.

Sources & disclaimer

• MicroChem — SU-8 2025 datasheet (No revision/date string is printed in the document body (a 5-page processing-guidelines PDF with no header/footer revision code). The mirror's filename indicates 'Ver4'.) · accessed 2026-07-10

1. Shaw et al.. Negative photoresists for optical lithography. IBM Journal of Research and Development (1997). doi:10.1147/rd.411.0081
   The IBM origin paper of SU-8.
2. Lorenz et al.. SU-8: a low-cost negative resist for MEMS. Journal of Micromechanics and Microengineering (1997). doi:10.1088/0960-1317/7/3/010
   15:1 aspect ratios in 1997 — the paper that made SU-8 a MEMS resist.
3. del Campo et al.. SU-8: a photoresist for high-aspect-ratio and 3D submicron lithography. Journal of Micromechanics and Microengineering (2007). doi:10.1088/0960-1317/17/6/R01
   The canonical SU-8 review.
4. Qasaimeh et al.. Microfluidic probes for use in life sciences and medicine. Lab Chip (2013). doi:10.1039/C2LC40898H
   Free-standing SU-8 microfluidic probes for live-cell chemistry.

Manufacturer datasheet values are starting points; optimal parameters depend on your substrate, equipment and environment. Product names and trademarks belong to their respective owners. NANYTE is not affiliated with the manufacturers listed. Last updated 2026-07-12.

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