https://nanyte.com/photoresists/lor-20b · last updated 2026-09-28
- Manufacturer
- MicroChem (MCC) — now Kayaku Advanced Materials
- Tone
- Not photoimageable (underlayer)
- Chemistry
- Ancillary (not photoimageable)
- Thickness
- 1.3–3.5 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 20B | 1000 | 3.5 |
| 1500 | 2.6 | |
| 2000 | 2.0 | |
| 2500 | 1.7 | |
| 3000 | 1.4 | |
| 3500 | 1.4 | |
| 4000 | 1.3 |
Values are the manufacturer’s starting points, not a guarantee — characterize on your own tool. Series digitized from a published figure are approximate (±10 %).
read from figure — the green filled-triangle trace legended LOR 20B on the 'Thickness vs. Spin Speed - LOR B Thick Series' chart, p.5. Seven plotted markers at 500 rpm intervals; no numeric table accompanies the chart.
- Most of the thickness swing happens in the first half of the sweep: 34,500 Å at 1000 rpm falls to 20,500 Å by 2000 rpm, then only to 13,000 Å by 4000 rpm.
- So a target near the thick end sits where the curve is steepest and thickness is most sensitive to speed and to dispense — worth confirming on a test wafer rather than reading off the chart.
- 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.
- An irregularly shaped substrate needs a slower spin.
- 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. At this thickness the bake also has several times more solvent to drive out than a sub-micron coat, so the time half of that matrix is worth exploring on a test wafer; the published undercut-versus-bake curves (Figures 5a and 5b) are measured on LOR 10B, a film roughly half this 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 20B 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 — expect the long end of any strip time at this thickness. 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 20B is a thick PMGI-based sacrificial underlayer from the fast-dissolving B series, spun beneath a conventional photoresist and never exposed. Underlayer thickness is chosen against the deposited film, not against the feature: the sacrificial layer has to be thick enough that the metal landing on the substrate and the metal landing on top of the imaging resist are genuinely disconnected, or the lift-off tears instead of releasing. At 1.30-3.45 µm this grade is aimed at depositions the sub-micron grades cannot break. The trade is that a thick, fast-dissolving film keeps undercutting for as long as the imaging resist above it is developing, so the ledge can travel further than intended under fine features — which is why the datasheet's own thick-film example pairs a 30-series underlayer with 20 µm lines rather than sub-micron ones. Prebake temperature remains the primary control, with develop time close behind.
Grades in this family
Other grades in the LOR B series line differ mainly in coating thickness:
Troubleshooting
Common failure modes for LOR 20B, 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.
The undercut under LOR 20B travels far past what I planned. How fast does it grow with develop time?
Fast. The datasheet's LOR B bars, measured on a 3 µm film (a thickness 20B reaches between 1000 and 1500 rpm), read about 3.6 µm of undercut at 2 min, about 6.7 µm at 2.5 min and about 9 µm at 3 min, so 30 extra seconds can add some 3 µm of ledge. Its LOR B/C image shows an undercut over 5 µm. Cut develop time or raise the prebake within 160-210 °C before resizing the pattern.
SOURCE: Kayaku Advanced Materials, "LOR and PMGI Resists" technical…
Kayaku Advanced Materials, "LOR and PMGI Resists" technical data sheet, Rev. D (August 2023) — Undercut vs. Develop Time chart, p.4; LOR B Thick Series chart, p.5; Varying LOR/PMGI Undercut images, p.6
Lift-off over LOR 20B leaves the stack half-attached. How hard should I push the remover?
Use Remover PG or another NMP- or DMSO-based remover. The datasheet baseline is two tanks: 60 °C for 30 min in the first, then a 60 °C rinse in the second, and ultrasonic action improves removal. Removal rate depends on the LOR soft-bake temperature and the bath temperature, and actual times vary with prebake, later processing and the pattern. Kayaku does not recommend acetone with LOR/PMGI, and MicroChemicals adds that it cannot be heated to speed lift-off and evaporates fast enough to redeposit lifted metal particles.
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. MicroChemicals application note "Lift-off Processes with Photoresist" — Suitable Lift-off Media
How much metal will LOR 20B carry?
Roughly 2.6 µm at the thick end. The datasheet wants the underlayer thicker than the deposit, typically by 33 %. LOR 20B coats about 3.5 µm at 1000 rpm and about 1.3 µm at 4000 rpm, so it covers about 2.6 µm down to 1 µm of metal. Most of the swing is below 2000 rpm (about 2 µm there), where thickness is most sensitive to spin speed.
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; Thickness vs. Spin Speed, LOR B Thick Series chart, p.5
Sources & disclaimer
- MicroChem (MCC) — now Kayaku Advanced Materials — LOR 20B 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.