https://nanyte.com/photoresists/su-8-2035 · last updated 2026-09-28
- Manufacturer
- Kayaku Advanced Materials
- Tone
- negative
- Chemistry
- Epoxy (SU-8 type)
- Thickness
- 33–119 µm
- Developer
- SU-8 Developer; ethyl lactate or diacetone alcohol may also be used
- Applications
- MEMS structural · High aspect ratio · Electroplating / molding
Cross-checked — two independent extractions agree on the spin curve and the single-value figures.
- Substrate
- Resist
- Exposed
Spin coating
Data points
| Series | rpm | µm | Published dose |
|---|---|---|---|
| SU-8 2035 | 1000 | 119 | 215–240 mJ/cm² · 85–110 µm row 240–260 mJ/cm² · 115–150 µm row within 10 % of a bracket edge |
| 2000 | 58 | 150–215 mJ/cm² · 45–80 µm row | |
| 3000 | 44 | — | |
| 4000 | 33 | 150–160 mJ/cm² · 25–40 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 — the diamond markers legended 'SU-8 2035' on Figure 1 'SU-8 2000 Thickness vs. Spin Speed', p.2 of the SU-8 2000, 2025-2075 Technical Data Sheet, August 2020. Four plotted markers at 1000, 2000, 3000 and 4000 rpm; no numeric table accompanies the chart. Reads are calibrated against the 20 µm axis ticks of the embedded chart image; values are reads to about ±1 µm.
- 119 µm at 1000 rpm drops by half to 58 µm at 2000 rpm, then 44 µm at 3000 and 33 µm at 4000 — only four speeds are plotted, and the gap between 1000 and 2000 rpm is where thickness is most sensitive.
- Kayaku's recommended program for the series: dispense 1 ml of resist per inch (25 mm) of substrate diameter, spread at 500 rpm for 5-10 s at 100 rpm/s, then spin at 2000 rpm for 30 s at 300 rpm/s, choosing the final speed from the spin chart.
- Remove the edge bead with EBR PG so the mask can seat in close contact.
- Adhesion
- HMDS not required — 'Adhesion promoters are typically not required.' Clean and dry the substrate first — piranha (H2SO4 and H2O2) with a DI rinse, or RIE or an oxygen barrel asher. For applications that include electroplating, an HMDS pre-treatment is recommended.
Soft bake
- Soft bake
- 95 °C · hotplate
- Notes
- Times are set by film thickness, at 65 °C and then at 95 °C: 25-40 µm → 0-3 min at 65 °C then 5-6 min at 95 °C; 45-80 µm → 0-3 then 6-9 min; 85-110 µm → 5 then 10-20 min; 115-150 µm → 5 then 20-30 min. Use a level hotplate — convection ovens are not recommended because a skin can form and trap solvent. To check the bake, cool the wafer to room temperature and return it to the hotplate; if the film wrinkles, bake a few more minutes and repeat until it does not.
SOURCE: Table 2 'Soft Bake Times', p.3 of the SU-8 2000, 2025-2075 Technical Data Sheet, August 2020
Exposure dose
SU-8 2035'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
- Dose follows the film you spin, not the grade name: 25-40 µm films take 150-160 mJ/cm², 45-80 µm 150-215, 85-110 µm 215-240 and 115-150 µm 240-260 mJ/cm². On glass and most metals multiply by 1.5-2.
- Post-exposure bake
- 95 °C · hotplate
| Film thickness | Dose |
|---|---|
| 25–40 µm | 150–160 mJ/cm² |
| 45–80 µm | 150–215 mJ/cm² |
| 85–110 µm | 215–240 mJ/cm² |
| 115–150 µm | 240–260 mJ/cm² |
| 160–225 µm | 260–350 mJ/cm² |
SOURCE: SU-8 2000 2025-2075 Technical Data Sheet
Table 3 'Exposure Dose', p.3 of the SU-8 2000, 2025-2075 Technical Data Sheet, August 2020 — indexed by film thickness and shared by the four grades that sheet covers; no wavelength is attached to the table.
Development
- Developer
- SU-8 Developer; ethyl lactate or diacetone alcohol may also be used
- Method
- immersion, spray or spray-puddle
- Rinse
- Spray and wash with fresh SU-8 developer for about 10 s, and again for another 10 s if needed, then air-dry with filtered pressurised air or nitrogen. A white film during an IPA rinse means the unexposed resist is under-developed: return it to SU-8 developer and repeat the rinse.
- Developer family
- Solvent
Not published for this resist: Dilution, Time — characterize on-tool.
SOURCE: SU-8 2000 2025-2075 Technical Data Sheet
Development section and Table 6 'Development Times for SU-8 Developer', p.4 of the SU-8 2000, 2025-2075 Technical Data Sheet, August 2020
Hard bake, etch & strip
- Hard bake
- 150–250 °C · 5–30 min (optional — when the resist stays on the device)
- Descum
- Not published — characterize on-tool
- Etch resistance
- Not characterised as an etch mask. Once cross-linked the film is described as chemically and thermally stable — 315 °C at 5 % weight loss, a glass transition of 210 °C — and extremely difficult to remove with solvent strippers.
- Stripper
- Minimally cross-linked SU-8 2000 swells and lifts off in Remover PG at 50-80 °C for 30-90 min; with a 30-100 nm OmniCoat underlayer the lift-off is clean. Fully cured or hard-baked SU-8 2000 cannot be removed without OmniCoat. To rework fully cross-linked films: piranha, plasma ash, RIE (200 W, 80 sccm O2, 8 sccm CF4, 100 mTorr, 10 °C), laser ablation or pyrolysis.
- Storage
- Store upright in tightly closed containers in a cool, dry place away from direct sunlight, light, acids, heat and ignition sources, at 4-21 °C (40-70 °F). Shelf life is thirteen months from date of manufacture.
SOURCE: Hard bake (cure) section, p.5 of the SU-8 2000, 2025-2075 Technical Data Sheet, August 2020
Where it's used
Practical notes from the datasheet
SU-8 2035 (7000 cSt, 69.95 % solids) sits between SU-8 2025 and 2050, and reaches 40-60 µm in the flat part of its curve. Its practical sweet spot is 2000-3000 rpm, where the curve has flattened and the 45-80 µm process row applies: 0-3 minutes at 65 °C then 6-9 minutes at 95 °C, 150-215 mJ/cm², post-bake 6-7 minutes at 95 °C, preceded by 1-2 minutes at 65 °C that the sheet marks optional for stress reduction, and 5-7 minutes in SU-8 Developer with strong agitation. Below 2000 rpm the film climbs quickly towards 120 µm and every step of the process lengthens. If surface cracks appear after development, the sheet anneals them with a couple of minutes at 150 °C. The cured epoxy is permanent — use OmniCoat underneath if it must be released.
Grades in this family
Other grades in the SU-8 2000 series line differ mainly in coating thickness:
Troubleshooting
Common failure modes for SU-8 2035, answered from the manufacturer's datasheet and application notes. These are starting points — your substrate, tooling and environment shift the specifics, so calibrate on-tool.
A white film appears on my SU-8 2035 when I rinse with IPA. What is it?
Underdeveloped resist. The datasheet reads a white film during the IPA rinse as unexposed SU-8 that hasn't fully dissolved. Put the wafer back in SU-8 developer (immerse or spray) until the film clears, then repeat the rinse. To avoid it, give thick SU-8 2035 the full Table 6 time — 4–5 min at 25–40 µm up to 10–15 min at 115–150 µm — with strong agitation, and finish with a ~10 s spray of fresh developer, plus a second 10 s spray if needed.
SOURCE: Kayaku SU-8 2000 (2025–2075) Technical Data Sheet, Aug 2020 — Development, Table 6, Rinse and Dry and note, p.4
What are the 65 °C steps in the SU-8 2035 bake tables for, and can I skip them?
In PEB the 65 °C step is marked optional and is there for stress reduction: 1 min for 25–40 µm, 1–2 min for 45–80 µm, 2–5 min for 85–110 µm and 5 min for 115–150 µm, each followed by the 95 °C bake. The soft bake table also pairs a 65 °C time with the 95 °C one — 0–3 min for films up to 80 µm, rising to 5 min at 85–150 µm — so at the thin end of SU-8 2035 it can be dropped, while the thick end lists it explicitly.
SOURCE: SU-8 2000 (2025–2075) Technical Data Sheet
Kayaku SU-8 2000 (2025–2075) Technical Data Sheet, Aug 2020 — Table 2 Soft Bake Times, p.3; Table 5 Post Exposure Bake Times, p.4
My SU-8 2035 thickness falls between two table rows. Which one do I use?
The soft-bake, dose and PEB tables are binned 25–40, 45–80, 85–110 and 115–150 µm, leaving gaps at 40–45, 80–85 and 110–115 µm — and SU-8 2035 crosses all of them, from about 33 µm at 4000 rpm to about 119 µm at 1000 rpm. In a gap, bracket between the neighbouring rows (for example 150–160 vs 150–215 mJ/cm² at 40–45 µm), then confirm with the wrinkle test after soft bake and a visible mask image after 1 min of PEB.
SOURCE: Kayaku SU-8 2000 (2025–2075) Technical Data Sheet, Aug 2020 — Figure 1, p.2; Tables 2–3, p.3; Table 5 and PEB note, p.4
Why does my 100 µm SU-8 2035 coat stay soft after a normal-looking soft bake?
Thick films need long bakes: 85–110 µm takes 5 min at 65 °C then 10–20 min at 95 °C, and 115–150 µm takes 5 min then 20–30 min. Use a level hotplate with good uniformity — in a convection oven a skin can form that traps solvent and extends the bake. Test the result: cool the wafer to room temperature, return it to the hotplate, and if it wrinkles keep baking a few more minutes and repeat until it no longer does.
SOURCE: Kayaku SU-8 2000 (2025–2075) Technical Data Sheet, Aug 2020 — Soft Bake and Table 2 Soft Bake Times, p.3
Sources & disclaimer
- Kayaku Advanced Materials — SU-8 2035 datasheet (SU-8 2000, 2025-2075 Technical Data Sheet, August 2020) · accessed 2026-09-10
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 2026-09-28.