https://nanyte.com/photoresists/ar-u-4030 · last updated 2026-09-28
- Manufacturer
- Allresist
- Tone
- image reversal
- Chemistry
- DNQ-novolak
- Thickness
- 1.8–4.1 µm
- Exposure dose
- 42 mJ/cm² (E0, broadband UV stepper)
- Developer
- AR 300-35
- Applications
- Image reversal · Lift-off · Etch mask
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 |
|---|---|---|
| AR-U 4030 | 1000 | 4.1 |
| 2000 | 2.9 | |
| 3000 | 2.4 | |
| 4000 | 2.1 | |
| 5000 | 1.9 | |
| 6000 | 1.8 |
Values are the manufacturer’s starting points, not a guarantee — characterize on your own tool. Series digitized from a published figure are approximate (±10 %).
read from figure, 'Spin curve' (D₀/µm 0-6.0 vs rpm 0-8000), p.32 of Allresist AR-U 4000 product-information sheet (as of January 2017); multi-grade chart with three individually legended traces — AR-U 4030 (topmost, dark-navy diamonds), AR-U 4040 (middle, red squares), AR-U 4060 (bottom, olive triangles). The topmost trace is AR-U 4030 two ways: its marker colour matches the dark-navy 'AR-U 4030' legend label sitting at that trace's right-hand endpoint, and it sorts correctly against the Properties I table's per-grade nominal 'Film thickness/4000 rpm (µm)' row (AR-U 4030 = 1.8, AR-U 4040 = 1.4, AR-U 4060 = 0.6, p.32) and the Coating-box captions ('4000 rpm, 60 s, 1.8/1.4/0.6 µm', p.33/p.34) — the thickest plotted trace is the grade with the largest nominal thickness. Note a real disagreement inside the datasheet: the figure's own 4000 rpm marker reads 2.09 µm, ~16% above the printed 1.8 µm nominal in the Properties I table and the matching Coating-box captions. The figure is what this curve reports, since the table value is a rounded nominal rather than a reading off this measured curve.
- Spin-speed-vs-thickness figure ('Spin curve', p.32, axes D₀/µm 0-6.0 vs rpm 0-8000): genuine multi-grade chart, three individually legended traces (AR-U 4030 topmost/navy, AR-U 4040 middle/red, AR-U 4060 bottom/olive)
- only the AR-U 4030 (topmost navy diamond) trace is plotted here, from its 6 markers between 1000-6000 rpm.
- Trace identity is fixed by both the legend colour and the Properties I nominal-thickness ranking (4030=1.8 > 4040=1.4 > 4060=0.6 µm at 4000 rpm, matching the top>mid>bottom trace order).
- The figure's own 4000 rpm marker (2.09 µm) is ~16% above the Properties I table's printed anchor (1.8 µm) — a genuine figure-vs-table disagreement in the source datasheet; the figure value is the one plotted here.
- No dispense volume or acceleration ramp is described anywhere in this document.
- Adhesion
- Datasheet specifies Allresist's own adhesion promoter AR 300-80 (Process chemicals table, p.32); does not mention HMDS specifically either way.
Soft bake
- Soft bake
- 90 °C · 60 s · hotplate
- Notes
- Referred to as 'Tempering' in the datasheet. ± 1 °C tolerance. Alternative: 85 °C, 25 min (1500 s) convection oven. Same schedule is used for both the positive-tone and negative/image-reversal processes. Corroborated by Processing instructions prose (p.35): for pure positive-tone use, 'a softbake at only 85 °C (oven) or 90 °C (hot plate) after coating is recommended... since this resist has the potential to be crosslinked due to its specific components.'
SOURCE: Process conditions diagrams, p.33 (positive) and p.34 (negative); Processing instructions, p.35
Exposure dose
The manufacturer publishes 42 mJ/cm² (E0, broadband UV stepper). Dose scales with film thickness and depends on your optics, so treat it as a starting point and run a dose array.
- As published
- 42 mJ/cm² is the image-wise dose for the reversal (negative-tone) process; the same resist run straight positive, with no reversal bake and no flood exposure, is published at 38 mJ/cm² instead.
- Reversal bake
- 115 °C · 4 min
- Flood exposure
- 74 mJ/cm²
Not published for this resist: Dose at 365 nm, Dose at 405 nm — characterize on-tool.
SOURCE: Process conditions, NEGATIVE (image-reversal) process diagram…
Process conditions, NEGATIVE (image-reversal) process diagram, p.34 of Allresist AR-U 4000 series product information (English); dose stated as "Exposure dose (E0, broadband UV stepper): 42 mJ/cm²". The positive-process diagram on p.33 gives a different dose (38 mJ/cm²) and is deliberately not used.
Development
- Developer
- AR 300-35
- Dilution
- 4:3
- Time
- 60 s
- Method
- puddle
- Rinse
- DI-H2O, 30 s
- Developer family
- TMAH or buffered alkaline
SOURCE: Process conditions negative process diagram, p.34
Hard bake, etch & strip
- Etch resistance
- No qualitative etch-resistance claim is made in the Characteristics list (unlike Allresist's AR-N 4300 sheet); only a raw rate table is given. Plasma etching rates (5 Pa, 240-250 V Bias, Properties II table, p.32): Ar-sputtering 8 nm/min, O2 169 nm/min, CF4 40 nm/min, 80% CF4 + 16% O2 89 nm/min.
- Stripper
- General Process chemicals table (p.32): AR 300-76, AR 300-72. Positive-process removal (p.33): 'AR 300-76 or O2 plasma ashing'. Negative-process removal (p.34): 'AR 300-70 or O2 plasma ashing' — this last figure ('AR 300-70') differs from the AR 300-76 used elsewhere in the same datasheet; reproduced verbatim as printed rather than corrected to 300-76, in case it is a distinct product rather than a misprint.
- Storage
- "Storage 6 month (°C): 8 - 12" (Properties I table, p.32).
Not published for this resist: Hard bake, Descum — characterize on-tool.
SOURCE: Process conditions diagrams, p.33 (positive) and p.34 (negative)
Where it's used
Practical notes from the datasheet
AR-U 4030 is Allresist's image-reversal resist in the AR-U 4000 series — described as a 'combination of novolac and bisazide' — that can be processed either as an ordinary positive resist or, with an image-reversal bake and flood exposure, as a negative resist with pronounced undercut lift-off profiles. In image-reversal (negative) mode the sequence is: image-wise broadband exposure (42 mJ/cm² for this grade) -> an 'image reversal bake' (115 °C/4 min hotplate, or 110 °C/25 min oven) that crosslinks the exposed areas via the resist's amine component -> an unmasked flood exposure (74 mJ/cm², roughly twice the image-wise dose) that renders the remaining, still-unexposed areas developable -> puddle development in AR 300-35 (4:3). Undercut and vertical-wall profiles are controlled by the same three levers in opposite directions: low image-wise dose + low reversal-bake temperature + longer development time maximizes undercut for lift-off, while high dose + high bake temperature + shorter development time produces vertical walls suited to etch masking. Critically, the image-wise exposure dose differs by process mode for the same grade — 38 mJ/cm² if used as a plain positive resist versus 42 mJ/cm² in the image-reversal negative mode — so the two figures must not be conflated; this recipe records the negative/image-reversal dose since that matches the resist's headline classification (tone: image-reversal), with the positive-mode figure noted separately. No h-line- or i-line-isolated dose is published anywhere; both the 42 mJ/cm² image-wise and 74 mJ/cm² flood-exposure doses are broadband (365/405/436 nm) figures.
Troubleshooting
Common failure modes for AR-U 4030, 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 AR-U 4030 image-reversal profiles come out vertical when I need a lift-off undercut — which knobs do I turn?
Three, per the datasheet. For more undercut, lower the image-wise dose, lower the reversal-bake temperature, and develop longer. For vertical walls, do the opposite: raise the image-wise dose, run the reversal bake hotter, and shorten development. The datasheet's negative-mode starting point for AR-U 4030 is 42 mJ/cm² image-wise (broadband stepper), a 115 °C / 4 min hotplate reversal bake (or 110 °C / 25 min in an oven), and 60 s puddle development. Change one knob at a time from there.
SOURCE: AR-U 4000 product information
AR-U 4000 product information (Allresist, as of January 2017) — Process conditions negative process, p.34; Processing instructions: Negative resist, Increasing the undercut / Vertical edges, p.35
In negative mode my AR-U 4030 areas that should clear stay behind — is it the flood or the developer?
Check both against the negative-mode column, not the positive one. The flood exposure, done without a mask after the reversal bake, should be about twice the image-wise dose: 74 mJ/cm² for AR-U 4030. Negative mode also takes a stronger developer: AR 300-35 at 4:3 for 60 s, where the positive process uses AR 300-35 at 1:1. The alternatives are AR 300-26 at 1:4 or AR 300-47 at 3:2. Carrying the positive-mode dilution over is an easy way to under-develop.
SOURCE: AR-U 4000 product information
AR-U 4000 product information (Allresist, as of January 2017) — Process conditions and Development recommendations (positive process), p.33; Process conditions negative process and Development recommendations (negative process), p.34
Can I run AR-U 4030 as a plain positive resist, and why won't it give an undercut that way?
Yes: without the reversal bake and flood it behaves as a positive resist, with 38 mJ/cm² and AR 300-35 1:1 for 60 s as the starting point. Keep the softbake at 90 °C on a hotplate (85 °C in an oven), because the resist can crosslink. An undercut cannot be obtained in positive mode. A high dose gives vertical edges, and a much lower one gives sloped trenches, for example 60°. A final flood exposure plus tempering at 95–105 °C raises the thermal stability of positive structures.
SOURCE: AR-U 4000 product information
AR-U 4000 product information (Allresist, as of January 2017) — Process conditions, p.33; Processing instructions: Positive resist, p.35
AR-U 4030 develop times wander from day to day — what should I control?
Temperature, dilution and bath age. The datasheet develops at 21–23 °C held to ±0.5 °C. Allresist's FAQ adds that metal-ion-free developers such as AR 300-47 are more sensitive to dilution errors than the buffered AR 300-26 and AR 300-35, so dilute carefully, by weight if possible, just before use. Open baths lose activity as they absorb CO2 from the air. Don't rinse mid-develop and then go back into the developer, either: the rate rises sharply on the second dip.
SOURCE: AR-U 4000 product information
AR-U 4000 product information (Allresist, as of January 2017) — Process conditions, pp.33–34; FAQs concerning photoresists (Allresist, 03.03.2016) — Question 10, pp.9–10
Sources & disclaimer
- Allresist — AR-U 4030 datasheet (As of January 2017) · accessed 2026-07-10
- https://www.allresist.com/portfolio-item/developer-ar-300-47/ — Allresist's own product page for developer AR 300-47: gives its main component as TMAH and its metal-ion content as under 0.1 ppm. Read together with the AR 300-26 page (sodium borate / sodium hydroxide) and the AR 300-35 page (sodium metasilicate / phosphate), it establishes that the developers this resist's own "Development recommendations" table offers span both a metal-ion-free and a metal-ion-containing 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 2026-09-28.