https://nanyte.com/photoresists/su-8-3050 · last updated 2026-09-28
- Manufacturer
- Kayaku MicroChem / MicroChem Corp.
- Tone
- negative
- Chemistry
- Epoxy (SU-8 type)
- Thickness
- 44.3–101.3 µm
- 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
Cross-checked — the spin curve (where published) and the single-value figures were read twice, independently, from the datasheet, with any disagreement settled against it.
- Substrate
- Resist
- Exposed
Spin coating
Data points
| Series | rpm | µm | Published dose |
|---|---|---|---|
| SU-8 3050 | 1000 | 101 | — |
| 2000 | 67 | 150–250 mJ/cm² · 40–80 µm rows (2) | |
| 3000 | 50 | 150–250 mJ/cm² · 40–80 µm rows (2) | |
| 4000 | 44 | 150–250 mJ/cm² · 40–50 µm rows (3) |
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 (no printed revision code) -- the same datasheet and figure used for SU-8 3025. 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 3050 is the filled+stroked square marker and the topmost (largest thickness) of the five stacked markers at every rpm column, consistent with it being the highest-viscosity grade (12,000 cSt, Table 1) and its top-of-legend position.
- 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 3050 thickness should be read from Figure 1 ('Spin speed vs. Thickness for SU-8 3000 resists', 21°C US & EU, p.1, the curve plotted above) or Figure 2 (23°C Japan & Asia, p.2, which is not plotted here).
- No numeric table exists for SU-8 3050 alone -- Table 1 (p.2) only ranks the five grades by viscosity (3050: 75.5% solids, 12,000 cSt, 1.153 g/ml density).
- 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. Exception: for applications requiring electroplating, the datasheet recommends pre-treating the substrate with MCC Primer 80/20 (HMDS).
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. The brackets are indexed by film thickness rather than by grade, and they overlap: this grade's own spin curve runs from 44.3 µm at 4000 rpm (which sits in the 20-50, 30-80 and 40-100 µm rows at once) to 101.3 µm at 1000 rpm (just past the top of the table), so bake to the row matching the thickness actually coated. 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.
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 3050'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
- SU-8 3050's thinnest coat, 44.3 µm, lands in three of the table's overlapping brackets at once — 20–50, 30–80 and 40–100 µm — and all three read 150–250 mJ/cm². The table stops at 100 µm; this grade spins to 101.3 µm.
- Post-exposure bake
- 95 °C · 3–5 min
| 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. 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.
- 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 (optional — for applications where the resist stays on the device)
- Descum
- Not published — characterize on-tool
- 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.
- 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.
- 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.
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 3050 is the highest-viscosity member (12,000 cSt, 75.5% solids, 1.153 g/ml) 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 thickest-coating grade at any given spin speed -- its own curve runs from 101.3 µm (1000 rpm) down to 44.3 µm (4000 rpm), stacked above 3035/3025/3010/3005 at every rpm column, consistent with its top rank by viscosity. It is generally preferred over the matching SU-8 2050 grade (SU-8 2000 series) when a thick, high-aspect-ratio process suffers adhesion loss or stress cracking, since the 3000 line was reformulated specifically to reduce both. Softbake time, PEB time, and develop time are all published as THICKNESS-BINNED ranges common to the whole 3000 series (not per-grade single values), and the brackets overlap, so each of those steps quotes the full bracket table and no single time is stated for the grade; exposure dose is likewise indexed to film thickness, and the datasheet does not attribute Table 3's doses to a single wavelength. As with the rest of the SU-8 family, fully cross-linked SU-8 3050 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:
Troubleshooting
Common failure modes for SU-8 3050, 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.
My SU-8 3050 is still tacky after soft bake at 95 °C. How long does a 100 µm film really need?
The top row of the soft-bake table, 40–100 µm, spans 15–45 min at 95 °C, and SU-8 3050 lives almost entirely in the 30–80 and 40–100 µm rows (about 44–101 µm on the 21 °C chart). Confirm the bake instead of trusting the clock: cool the wafer to room temperature, return it to the hotplate, and if it wrinkles keep baking a few minutes and repeat. Use a level, uniform hotplate — a convection oven can form a skin that traps solvent and drags the bake out.
SOURCE: Kayaku MicroChem SU-8 3000 datasheet (no revision printed) — Figure 1, p.1; Soft Bake, Table 2 and note, p.2
How do I tell whether my SU-8 3050 exposure was right before I develop?
Watch the PEB hotplate. Optimal exposure produces a visible latent image within 5–15 s of the wafer going on the hotplate, and not before. If there is no image during or after PEB (it should be clear after 1 min at 95 °C), exposure, temperature or both were short. For SU-8 3050's thickness range the dose table gives 150–250 mJ/cm² on silicon, and PEB is an optional 1 min at 65 °C for stress reduction followed by 3–5 min at 95 °C, straight after exposure.
SOURCE: MicroChem SU-8 3000 datasheet
Kayaku MicroChem SU-8 3000 datasheet (no revision printed) — Exposure note and Table 3 Exposure Dose, p.2; Post Exposure Bake note and Table 5, p.3
Deep vias in SU-8 3050 won't clear. How long and how hard should I develop?
Plan on the long end. Table 6 gives 6–12 min for 30–80 µm and 7–15 min for 40–100 µm in SU-8 developer, and those are approximate since dissolution rate varies widely with agitation. Strong agitation is recommended for thick, high-aspect-ratio structures, and an ultrasonic or megasonic bath helps develop out vias and holes. Rinse with fresh developer for ~10 s, then IPA for ~10 s — a white film in the IPA means more developer time is needed.
SOURCE: Kayaku MicroChem SU-8 3000 datasheet (no revision printed) — Develop, Table 6, Rinse and Dry and note, p.3
Can I strip SU-8 3050 once it has been hard baked?
Not with solvent alone. Remover PG at 50–80 °C for 30–90 min swells and lifts only minimally cross-linked SU-8 3000; it will not remove fully cured or hard-baked film unless OmniCoat (30–100 nm) was put down first. Otherwise rework means piranha or other oxidizing acids, plasma ash, RIE (200 W, 80 sccm O₂, 8 sccm CF₄, 100 mTorr, 10 °C), laser ablation or pyrolysis. If the SU-8 3050 is meant to stay, the published hard bake is a ramp or step to 150–200 °C on a hotplate or in an oven.
SOURCE: Kayaku MicroChem SU-8 3000 datasheet (no revision printed) — Hard Bake (cure), p.3; Removal and Plasma Removal, p.4
Sources & disclaimer
- Kayaku MicroChem / MicroChem Corp. — SU-8 3050 datasheet · accessed 2026-07-22
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.