SU-8 3025 process recipe

Spin coating

SU-8 3025 is spin-coated to —. 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 (family-wide, not grade-specific): dispense 1 ml resist per inch (25 mm) of substrate diameter; spin at 500 rpm for 5-10 s at 100 rpm/s acceleration (spread step); then spin at 3000 rpm for 30 s at 300 rpm/s acceleration as a generic starting point — the actual final rpm/time for a target SU-8 3025 thickness should be read from Figure 1 ('Spin speed vs. Thickness for SU-8 3000 resists', 21°C US & EU, p.1) or Figure 2 (23°C Japan & Asia, p.2), each of which plots all five grades (3005/3010/3025/3035/3050) as separate traces vs. 1000-5000 rpm with NO accompanying numeric table. Figure 1 (21°C US & EU) has now been digitized above by extracting the marker vector-path pixel positions and axis tick-label pixel positions directly from the PDF page content stream (not a manual on-screen eyeball estimate); the SU-8 3025 trace was identified as the filled-diamond series, 3rd from the top of five, consistent with its legend position and Table 1's viscosity ordering (3025 = 4400 cSt, the middle of the five grades). Figure 2 (23°C Japan & Asia) was not digitized — only Figure 1 is captured as the primary curve, matching the convention used elsewhere in this library for datasheets publishing two ambient-condition charts. No numeric table exists for SU-8 3025 alone — Table 1 (p.2) only ranks the five grades by viscosity. No edge-bead-removal step is described anywhere in this SU-8 3000 datasheet, and no resist rehydration hold is mentioned either.

Soft bake

Soft bake

95 °C · hotplate

Notes

95°C is fixed across all thickness brackets; only bake TIME varies by film thickness per Table 2: 4-10 µm -> 2-3 min; 8-15 µm -> 5-10 min; 20-50 µm -> 10-15 min; 30-80 µm -> 10-30 min; 40-100 µm -> 15-45 min. time_s is left null because no confident SU-8 3025-specific thickness/bracket could be established (see spinNotes). Convection ovens are explicitly NOT recommended — a skin can form on the resist and trap solvent, incompletely drying the film. Vendor's own optimization check: after the prescribed bake, cool the wafer to room temperature, then return it to the hotplate; if the film wrinkles, continue baking and repeat the cool/reheat cycle until wrinkles no longer appear.Show more

SOURCE: Table 2 'Soft Bake Times', p.2 of SU-8 3000 Permanent Epoxy Negative Photoresist datasheet, Kayaku MicroChem/MicroChem Corp.

Exposure dose

The manufacturer does not publish a clearing dose for SU-8 3025. Determine it with a dose array on your own tool.

As published

'SU-8 3000 is most commonly exposed with conventional UV (350-400 nm) radiation, although i-line (365 nm) is recommended' (Processing Guidelines, p.1). Table 3's dose values are not explicitly labeled as i-line-only.Show more

Post-exposure bake

95 °C

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

Development

Developer

SU-8 Developer (MicroChem's proprietary solvent-based developer); ethyl lactate and diacetone alcohol are also stated to work

Rinse

Spray/wash with fresh SU-8 developer for ~10 s, then a second spray/wash with isopropyl alcohol (IPA) for ~10 s, then air/nitrogen dry with filtered pressurized gas. A white film appearing during the IPA rinse indicates under-development — immerse or spray with more SU-8 developer and repeat the rinse. Ultrasonic or megasonic bath agitation is recommended for developing out vias/holes in high-aspect-ratio structures.Show more

Developer family

Solvent

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

SOURCE: Develop and Rinse-and-Dry sections, p.3 of SU-8 3000 Permanent Epoxy Negative Photoresist datasheet, Kayaku MicroChem/MicroChem Corp.

Hard bake, etch & strip

Etch resistance

Listed under Features as 'Excellent dry etch resistance' (p.1, no numeric selectivity given). The Plasma Removal section (p.4) gives an RIE recipe (200 W, 80 sccm O2, 8 sccm CF4, 100 mTorr, 10°C) specifically for STRIPPING crosslinked SU-8 — i.e. cured SU-8 requires an aggressive dedicated RIE recipe to remove at all, consistent with strong etch resistance during normal device processing.Show more

Stripper

MicroChem's Remover PG, 50-80°C bath, 30-90 min immersion — swells and lifts off minimally-crosslinked SU-8 3000; achieves a clean, thorough lift-off of fully-crosslinked SU-8 3000 only if a 30-100 nm OmniCoat sacrificial layer was applied first. Will NOT remove fully-cured/hard-baked SU-8 3000 without OmniCoat underneath. To rework fully cross-linked material with no OmniCoat: oxidizing acid solutions (piranha etch), plasma ash, RIE (200 W, 80 sccm O2, 8 sccm CF4, 100 mTorr, 10°C), laser ablation, or pyrolysis.Show more

Storage

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

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

SOURCE: Hard Bake (cure) section, p.3 of SU-8 3000 Permanent Epoxy Negative Photoresist datasheet, Kayaku MicroChem/MicroChem Corp.

Where it's used

SU-8 3025 is the third-lowest-viscosity member (4,400 cSt, 72.3% solids) of Kayaku MicroChem's five-grade SU-8 3000 permanent epoxy series (3005/3010/3025/3035/3050), an 'improved formulation' of SU-8 2000 offering better adhesion and lower coating stress for thick (family-wide 4-120 µm single-coat), high-aspect-ratio (>5:1), permanent MEMS structures that are imaged, cured, and left on the device rather than lifted off. Within the 3000 series it is the mid-viscosity option — thicker-coating than 3005 and 3010, thinner than 3035 and 3050 — and it is generally preferred over the matching SU-8 2000 grades when a process suffers adhesion loss or stress cracking, since the 3000 line was reformulated specifically to reduce both. Figures 1-2 plot all five grades' film thickness against 1000-5000 rpm spin speed on one shared axis with no accompanying numeric table; because a prior recipe already in this library (SU-8 2050) was built from a misread multi-grade SU-8 chart with errors of 20-42% at every point, no spin-curve points are published here for SU-8 3025 — spinNotes records the viscosity-ranking argument that was available (a physically sound bound on which curve is 3025, but not a substitute for digitizing it) and why that fell short of a confident pixel-level read. Softbake time, PEB time, exposure dose, and develop time are all published as THICKNESS-BINNED ranges common to the whole 3000 series (not per-grade single values), so every corresponding scalar field here is null with the full bracket table quoted in its own notes — reporting a single number would be false precision without first knowing which bracket a real SU-8 3025 process actually lands in. As with the rest of the SU-8 family, fully cross-linked SU-8 3025 is notoriously difficult to strip: MicroChem's Remover PG only lifts minimally-crosslinked resist (or fully-crosslinked resist sitting over a sacrificial OmniCoat layer); a hard-baked film with no OmniCoat underneath requires piranha etch, plasma ashing, RIE, laser ablation, or pyrolysis to remove.

Sources & disclaimer

• Kayaku MicroChem / MicroChem Corp. — SU-8 3025 datasheet · accessed 2026-07-10

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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