https://nanyte.com/photoresists/su-8-3025 · last updated 2026-07-26
- Manufacturer
- Kayaku MicroChem / MicroChem Corp.
- Tone
- negative
- Chemistry
- Epoxy (SU-8 type)
- Developer
- SU-8 Developer (MicroChem's proprietary solvent-based developer); ethyl lactate and diacetone alcohol are also stated to work
- Applications
- MEMS structural · High aspect ratio · Electroplating / molding
- Substrate
- Resist
- Exposed
Spin coating
Data points
| Series | rpm | µm | Published dose |
|---|---|---|---|
| SU-8 3025 | 1000 | 58 | 150–250 mJ/cm² · 40–80 µm rows (2) |
| 2000 | 37 | 150–250 mJ/cm² · 30–50 µm rows (2) | |
| 3000 | 25 | 150–250 mJ/cm² · 20–50 µm row | |
| 4000 | 23 | 150–250 mJ/cm² · 20–50 µm row |
Values are the manufacturer’s starting points, not a guarantee — characterize on your own tool. Series digitized from a published figure are approximate (±10 %).
Published dose is the datasheet’s own thickness bracket, quoted as printed — the full table and its citation are in the exposure section. A thickness the table does not cover shows nothing, and a thickness within 10 % of a bracket edge shows every bracket it could fall in.
read from Figure 1, "Spin speed vs. Thickness for SU-8 3000 resists (21°C US & EU)", p.1 of the Kayaku Microchem/MicroChem "SU-8 3000 Permanent Epoxy Negative Photoresist" datasheet (BYU cleanroom mirror; no printed revision code). The chart plots five grades (3050/filled square, 3035/filled triangle, 3025/filled diamond, 3010/filled circle, 3005/open square), each with 4 markers at 1000/2000/3000/4000 rpm. SU-8 3025 is the filled-diamond series, 3rd from the top of five at every rpm, consistent with its legend position (3rd of 3050/3035/3025/3010/3005) and Table 1's viscosity ordering (3025 = 4400 cSt, the middle of the five grades). No numeric per-rpm table exists for SU-8 3025 alone in this datasheet — Tables 2/3/5/6 are thickness-binned ranges shared across the whole 3000 series, not per-grade spin data.
- 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) is the curve plotted above; the SU-8 3025 trace is 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).
- Only that chart is plotted here — Figure 2 (23°C Japan & Asia) is not.
- 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.
- Adhesion
- HMDS not required — Adhesion promoters are stated as 'typically not required' for substrates cleaned per the recommended piranha (H2SO4+H2O2) wet etch or RIE/O2-barrel-ash prep.
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. No single soft-bake time is quoted here, because the row that applies depends on the film thickness actually coated.
SOURCE: Table 2 'Soft Bake Times', p.2 of SU-8 3000 Permanent Epoxy…
Table 2 'Soft Bake Times', p.2 of SU-8 3000 Permanent Epoxy Negative Photoresist datasheet, Kayaku MicroChem/MicroChem Corp.
Exposure dose
SU-8 3025's dose is published against film thickness, not as a single number. Read the row for the film you coat and run a dose array around it.
- As published
- The bins overlap here, so a mid-range film matches more than one: 100–200 mJ/cm² for 4–10 µm, 125–200 mJ/cm² at 8–15 µm, and a flat 150–250 mJ/cm² across every bracket from 20 to 100 µm.
- Post-exposure bake
- 95 °C
| Film thickness | Dose |
|---|---|
| 4–10 µm | 100–200 mJ/cm² |
| 8–15 µm | 125–200 mJ/cm² |
| 20–50 µm | 150–250 mJ/cm² |
| 30–80 µm | 150–250 mJ/cm² |
| 40–100 µm | 150–250 mJ/cm² |
SOURCE: Table 3 'Exposure Dose', p.2 of the SU-8 3000 Permanent Epoxy…
Table 3 'Exposure Dose', p.2 of the SU-8 3000 Permanent Epoxy Negative Photoresist datasheet, Kayaku MicroChem/MicroChem Corp. Brackets are indexed by film thickness and overlap exactly as printed. Not attributed to a specific wavelength — the document recommends i-line but states conventional UV (350-400 nm) is most common.
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.
- 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…
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
- Hard bake
- 150–200 °C
- Descum
- Not published — characterize on-tool
- Etch resistance
- Listed under Features as 'Excellent dry etch resistance' (p.1, no numeric selectivity given).
- 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.
- Storage
- Store upright, in tightly closed containers, in a cool, dry environment away from direct sunlight, at 40-70°F (4-21°C).
SOURCE: Hard Bake (cure) section, p.3 of SU-8 3000 Permanent Epoxy…
Hard Bake (cure) section, p.3 of SU-8 3000 Permanent Epoxy Negative Photoresist datasheet, Kayaku MicroChem/MicroChem Corp.
Where it's used
Practical notes from the datasheet
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, and the five traces are separable only by viscosity ranking, which bounds which curve belongs to 3025 without pinning its values — so no spin-curve points are published here for SU-8 3025. 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 no single number is quoted for any of them and the full bracket table is printed with each step instead — reporting one 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.
Grades in this family
Other grades in the SU-8 3000 series line differ mainly in coating thickness:
| Grade | Thickness |
|---|---|
| SU-8 3050 | 44.3–101.3 µm |
| SU-8 3025 (this page) | — |
Sources & disclaimer
- Kayaku MicroChem / MicroChem Corp. — SU-8 3025 datasheet · accessed 2026-07-10
- Shaw et al.. Negative photoresists for optical lithography. IBM Journal of Research and Development (1997). doi:10.1147/rd.411.0081The IBM origin paper for the EPON-based epoxy negative resist that became SU-8, describing its formulation and use as a thick optical-lithography resist.
- Lorenz et al.. SU-8: a low-cost negative resist for MEMS. Journal of Micromechanics and Microengineering (1997). doi:10.1088/0960-1317/7/3/010Established SU-8 as a MEMS structural resist, producing thick high-aspect-ratio structures by near-UV lithography.
- del Campo, Greiner. 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/R01Widely cited review of SU-8 processing (coat, bake, expose, develop) for high-aspect-ratio and 3D microstructures across the SU-8 family.
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 2026-07-26.