https://nanyte.com/photoresists/lor-10a · last updated 2026-09-28
- Manufacturer
- MicroChem (MCC) — now Kayaku Advanced Materials
- Tone
- Not photoimageable (underlayer)
- Chemistry
- Ancillary (not photoimageable)
- Thickness
- 0.6–1.4 µm
- Exposure dose
- Not exposed — dissolves in developer
- Developer
- 0.26N or 0.24N TMAH (no product named); metal-ion-bearing developers are not rated for LOR A (selection guide, p.7).
- Applications
- Lift-off
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
- Underlayer
- Resist
- Exposed
Spin coating
Data points
| Series | rpm | µm |
|---|---|---|
| LOR 10A | 1000 | 1.4 |
| 1500 | 1.0 | |
| 2000 | 0.87 | |
| 2500 | 0.72 | |
| 3000 | 0.63 | |
| 3500 | 0.59 | |
| 4000 | 0.58 |
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 — the green filled-triangle trace legended LOR 10A on the 'Thickness vs. Spin Speed - LOR A Thick Series' chart, p.5. Seven plotted markers at 500 rpm intervals; no numeric table accompanies the chart.
- From 14,300 Å at 1000 rpm the curve falls steeply to about 8,700 Å by 2000 rpm, then flattens hard — 3500 and 4000 rpm differ by only 100 Å.
- So the usable control range is really 1000-2500 rpm, and targeting much below 0.6 µm means dropping to LOR 7A or 5A rather than spinning faster.
- Coating parameters are published for the product line rather than per grade: 5 ml dispensed dynamically over 3-5 s onto a 150 mm wafer at 300-500 rpm, 10,000 rpm/s acceleration to a 3,000 rpm terminal speed, 45 s spin, with EBR PG for edge-bead and whisker removal.
- Adhesion
- HMDS not required — "Primers, such as HMDS, are typically not required" when LOR/PMGI is used as recommended; the datasheet describes excellent adhesion across semiconductor substrates. To dehydrate the surface first, bake at 200 °C for 5 min. LOR/PMGI is virtually insoluble in typical photoresist solvents, so a properly baked underlayer does not intermix with the imaging resist above it.
Soft bake
- Soft bake
- 160–210 °C · hotplate
- Notes
- The prebake dries the film and fixes its dissolution and undercut rate, and no grade-specific temperature or time is published. The recommended prebake range for the product line is 160-210 °C, hotplate preferred, and some PMGI products bake as high as 280 °C. Prebake temperature has the greatest influence on undercut rate, with prebake time, developer choice, develop mode and especially develop time behind it. That headroom matters for this grade in particular: the datasheet pairs it with a high-temperature negative resist in its opening figure, and the underlayer has to survive that resist's own bake without its undercut behaviour drifting. The published undercut-versus-bake curves (Figures 5a and 5b) are measured on LOR 10B — same nominal thickness class, faster dissolution — so they give the shape rather than numbers to copy.
SOURCE: Rev. D p.3: 'The recommended bake temperature range is 160°C –…
Rev. D p.3: 'The recommended bake temperature range is 160°C – 210°C'; 'Hot plates are the preferred tool for the prebake step.'
Exposure
LOR 10A is not photoimageable. It is not exposed at all — it is coated beneath an imaged top resist and undercut laterally during development. See the development step below.
Development
- Developer
- 0.26N or 0.24N TMAH (no product named); metal-ion-bearing developers are not rated for LOR A (selection guide, p.7).
- Developer family
- TMAH or buffered alkaline
Not published for this resist: Dilution, Time, Method, Rinse — characterize on-tool.
SOURCE: Product description, the LOR/PMGI process-flow section and the…
Product description, the LOR/PMGI process-flow section and the product selection guide, Kayaku "LOR and PMGI Resists" technical data sheet, Rev. D (August 2023)
Hard bake, etch & strip
- Stripper
- Remover PG. EBR PG removes edge beads and whiskers and is also an effective spin-bowl cleaner and a rework solvent for unbaked wafers.
- Storage
- Store upright in original sealed containers in a dry area between 10 and 24 °C (50-76 °F), away from ignition sources, light, heat, oxidants, acids and reducers. Do not use after the expiration date, 13 months from manufacture.
Not published for this resist: Hard bake, Descum, Etch resistance — characterize on-tool.
Where it's used
Practical notes from the datasheet
LOR 10A is the thick end of the slow-dissolving A series, a PMGI-based sacrificial film spun beneath a conventional photoresist and never exposed. It is also the grade Kayaku leads the datasheet with: Figure 1 shows LOR 10A used under a high-temperature negative resist, which is the case the A series is built for — a slow underlayer whose undercut opens gradually and predictably, under an imaging resist whose own processing runs hot. Choosing 10A over the same-thickness 10B is not a thickness decision; both land around one micron. It is a decision to take the slower film, trading a wider undercut per unit develop time for a wider process window before the ledge runs too far under a feature. At 0.58-1.43 µm the film is thick enough for substantial metal stacks, and thick enough that prebake temperature and develop time both start to matter more than they do on the sub-micron A grades.
Grades in this family
Other grades in the LOR A series line differ mainly in coating thickness:
Troubleshooting
Common failure modes for LOR 10A, 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.
Will LOR 10A survive a hot deposition or a hot-baked negative resist on top?
The datasheet rates the underlayer for it: LOR/PMGI has a Tg above 190 °C and is compatible with high-temperature sputter, evaporative metal and dielectric deposition, and Figure 1 shows 10A under a high-temperature negative resist with about 1 µm of undercut on 20 µm lines. Check the imaging resist separately. MicroChemicals notes that resist heated past its softening point during deposition rounds over and gets coated all over, which makes lift-off difficult and leaves fences; its remedies include better heat coupling to the holder and a lower deposition rate.
SOURCE: Kayaku Advanced Materials, "LOR and PMGI Resists" technical…
Kayaku Advanced Materials, "LOR and PMGI Resists" technical data sheet, Rev. D (August 2023) — Features and Figure 1, p.1; Deposition Process, p.4. MicroChemicals application note "Lift-off Processes with Photoresist" — Thermal Effects on the Resist Structures; "Fences" after Lift-off
I chose LOR 10A and can't get more than about a micron of undercut. Should it be 10B?
If you need more than a micron, yes. The two grades land at similar thicknesses (10A about 0.6-1.4 µm, 10B about 0.65-1.6 µm), but the product-range chart puts the A series at a medium dissolution rate and B at fast, and the selection guide rates LOR A only some compatibility for undercuts above 1 µm where LOR B is recommended. Below that, a cooler prebake and a longer develop on 10A are the levers the datasheet names.
SOURCE: Kayaku Advanced Materials, "LOR and PMGI Resists" technical…
Kayaku Advanced Materials, "LOR and PMGI Resists" technical data sheet, Rev. D (August 2023) — Product Range chart, p.1; Soft-Bake/Prebake Process, p.3; LOR A and LOR B Thick Series charts, p.5; Product Selection Guide, p.7
Drain lines clog since we started running LOR 10A in a shared coater bowl. What does the datasheet say?
It names that problem: mixing a conventional resist process with LOR/PMGI can clog drain lines, and a dedicated coat bowl and drain are recommended, though not mandatory. If EBR PG is used for clean-up and edge-bead removal, LOR and conventional resists can share the same system. The coating hardware must also be compatible with cyclopentanone.
SOURCE: Kayaku Advanced Materials, "LOR and PMGI Resists" technical…
Kayaku Advanced Materials, "LOR and PMGI Resists" technical data sheet, Rev. D (August 2023) — Coating Process, p.2; Edge Bead Removal, p.3
Sources & disclaimer
- MicroChem (MCC) — now Kayaku Advanced Materials — LOR 10A datasheet (Rev. D, August 2023 (printed in the footer of every page)) · 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.