https://nanyte.com/photoresists/lor-15b · last updated 2026-09-28
- Manufacturer
- MicroChem (MCC) — now Kayaku Advanced Materials
- Tone
- Not photoimageable (underlayer)
- Chemistry
- Ancillary (not photoimageable)
- Thickness
- 1–2.2 µm
- Exposure dose
- Not exposed — dissolves in developer
- Developer
- 0.24N TMAH or a metal-ion-bearing developer (no product named); 0.26N TMAH has some compatibility (selection guide, p.7).
- 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 15B | 1000 | 2.2 |
| 1500 | 1.6 | |
| 2000 | 1.4 | |
| 2500 | 1.2 | |
| 3000 | 1.1 | |
| 3500 | 1.0 | |
| 4000 | 1.0 |
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 red filled-square trace legended LOR 15B on the 'Thickness vs. Spin Speed - LOR B Thick Series' chart, p.5, the middle of the five traces. Seven plotted markers at 500 rpm intervals; no numeric table accompanies the chart.
- A well-behaved curve that lands on a round number at each end — 21,700 Å at 1000 rpm down to almost exactly 10,000 Å at 4000, so the grade covers a clean factor of two.
- The knee sits around 1500-2000 rpm; below it thickness climbs quickly, above it the curve is nearly flat and speed buys little.
- 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. On a B-series film that lever matters more than on an A grade because the starting dissolution rate is already high; conveniently, the published undercut-versus-bake curves (Figures 5a and 5b) are measured on LOR 10B, the nearest sibling to this grade in both series and thickness.
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 15B 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
- 0.24N TMAH or a metal-ion-bearing developer (no product named); 0.26N TMAH has some compatibility (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 15B is a PMGI-based sacrificial underlayer from the fast-dissolving B series, spun beneath a conventional photoresist and never exposed. It sits between 10B and 20B, which makes it the grade for deposits in the one-to-two micron range that want B-series speed — a generous ledge opened quickly — without the extra thickness of 20B. The reason to want speed is mechanical: a thick deposit needs the underlayer to pull back far enough that the metal breaks cleanly at the edge rather than tearing. The reason to be careful with it is the same property seen from the other side, because a fast film keeps undercutting for as long as the imaging resist above is developing, and the datasheet singles out develop time as a particularly strong influence on where the ledge ends up. Of all the B grades, this one has the closest published characterisation to lean on: the undercut-versus-bake figures are measured on LOR 10B, its immediate neighbour.
Grades in this family
Other grades in the LOR B series line differ mainly in coating thickness:
Troubleshooting
Common failure modes for LOR 15B, 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.
An ethyl-lactate imaging resist leaves a scummy foot over LOR 15B. Which bake fixes it?
Bake the LOR at 180 °C or higher. One of the selection guide's advice notes says intermixing can occur with ethyl-lactate-based resists at temperatures below 180 °C, and the datasheet says a properly baked LOR/PMGI film is virtually insoluble in typical resist solvents, so the layers stay separate. The cost is a slower undercut: on the nearest published curve, LOR 10B, the rate drops about 1 nm/s per °C across 170-190 °C, so re-balance with develop time.
SOURCE: Kayaku Advanced Materials, "LOR and PMGI Resists" technical…
Kayaku Advanced Materials, "LOR and PMGI Resists" technical data sheet, Rev. D (August 2023) — Substrate Preparation, p.2; Figure 5a, p.3; Product Selection Guide Advice note 3, p.7
A slow-spun LOR 15B film gives sloped sidewalls in immersion. Should I switch to spray?
At that thickness, yes. The datasheet says straighter sidewalls with thick (>2 µm) LOR/PMGI layers come from spray development. LOR 15B only passes 2 µm near 1000 rpm, where it coats about 2.2 µm; by 1500 rpm it is down to about 1.6 µm, so the advice covers the slow end of its curve.
SOURCE: Kayaku Advanced Materials, "LOR and PMGI Resists" technical…
Kayaku Advanced Materials, "LOR and PMGI Resists" technical data sheet, Rev. D (August 2023) — Development Process, p.4; Thickness vs. Spin Speed, LOR B Thick Series chart, p.5
Can I rework a wafer after coating LOR 15B?
Before the bake, yes: EBR PG is an effective solvent for rework of unbaked wafers as well as for spin-bowl clean-up. After baking, the removal route the datasheet gives is Remover PG or another NMP- or DMSO-based remover, and it notes the removal rate depends on the soft-bake temperature and the bath temperature. Acetone and conventional edge-bead removers are not recommended with LOR/PMGI.
SOURCE: Kayaku Advanced Materials, "LOR and PMGI Resists" technical…
Kayaku Advanced Materials, "LOR and PMGI Resists" technical data sheet, Rev. D (August 2023) — Edge Bead Removal, p.3; Lift-Off Process, p.4
Sources & disclaimer
- MicroChem (MCC) — now Kayaku Advanced Materials — LOR 15B 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.