https://nanyte.com/photoresists/lor-15a · last updated 2026-09-12
- Manufacturer
- MicroChem (MCC) — now Kayaku Advanced Materials
- Tone
- Not photoimageable (underlayer)
- Chemistry
- Ancillary (not photoimageable)
- Thickness
- 1.0–2.6 µm
- Exposure dose
- Not exposed — dissolves in developer
- Developer
- No specific commercial developer product is named for this grade; the datasheet states LOR/PMGI is compatible with both metal-ion-free (TMAH) and metal-ion-bearing developer chemistries.
- Applications
- Lift-off
Cross-checked — two independent extractions agree on the spin curve and the single-value figures.
- Substrate
- Underlayer
- Resist
- Exposed
Spin coating
Data points
| Series | rpm | µm |
|---|---|---|
| LOR 15A | 1000 | 2.6 |
| 1500 | 1.9 | |
| 2000 | 1.6 | |
| 2500 | 1.3 | |
| 3000 | 1.1 | |
| 3500 | 1.0 | |
| 4000 | 0.99 |
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 purple cross-marker trace legended LOR 15A on the 'Thickness vs. Spin Speed - LOR A Thick Series' chart, p.5, the highest of the four traces. Seven plotted markers at 500 rpm intervals; no numeric table accompanies the chart.
- The steepest trace on the A-thick chart: 25,600 Å at 1000 rpm falls to 15,500 Å by 2000 and flattens toward 9,900 Å at 4000 rpm, where it has essentially bottomed out.
- The whole range above about 1.5 µm lives below 2000 rpm, so the thick end is where speed control matters and a slow-spin target is worth confirming on a test wafer.
- 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.
Soft bake
- Soft bake
- Not published — characterize on-tool
- Notes
- The prebake dries the film and fixes its dissolution and undercut rate, and no grade-specific temperature or time is published.
SOURCE: "Soft-Bake/Prebake Process" section and Figures 5a-5b, Kayaku…
"Soft-Bake/Prebake Process" section and Figures 5a-5b, Kayaku "LOR and PMGI Resists" technical data sheet, Rev. D (August 2023)
Exposure
LOR 15A 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
- No specific commercial developer product is named for this grade; the datasheet states LOR/PMGI is compatible with both metal-ion-free (TMAH) and metal-ion-bearing developer chemistries.
- 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 4 and 27 °C (40-80 °F), away from ignition sources, light, heat, oxidants, acids and reducers. Do not use after the expiration date.
Not published for this resist: Hard bake, Descum, Etch resistance — characterize on-tool.
Where it's used
Practical notes from the datasheet
LOR 15A is the thick end of the slow-dissolving A series, a PMGI-based sacrificial film spun beneath a conventional photoresist and never exposed. It exists for a specific combination: a deposit heavy enough to need a couple of microns of sacrificial layer underneath, on a pattern fine enough that a fast-dissolving B or C grade would undercut past the feature while the imaging resist above was still developing. That trade — thickness without speed — is the whole reason the A series extends this far up. Prebake temperature remains the primary control over how far the ledge opens, with develop time close behind, and on a film this thick bake time matters more than it does on the thin grades. Nothing here is exposed, so there is no dose, no tone and no post-exposure bake to set.
Grades in this family
Other grades in the LOR A series line differ mainly in coating thickness:
Sources & disclaimer
- MicroChem (MCC) — now Kayaku Advanced Materials — LOR 15A 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 2026-09-12.