https://nanyte.com/photoresists/lor-7b · last updated 2026-09-28
- Manufacturer
- MicroChem (MCC) — now Kayaku Advanced Materials
- Tone
- Not photoimageable (underlayer)
- Chemistry
- Ancillary (not photoimageable)
- Thickness
- 0.3–0.9 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 7B | 1000 | 0.90 |
| 1500 | 0.72 | |
| 2000 | 0.57 | |
| 2500 | 0.44 | |
| 3000 | 0.39 | |
| 3500 | 0.34 | |
| 4000 | 0.32 |
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 dark-blue filled-circle trace legended LOR 7B 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.
- The lowest trace on the B-series chart, falling from 9,000 Å at 1000 rpm to 3,200 Å at 4000 rpm — a factor of nearly three, so speed is a real lever across this grade's whole range, unlike the thicker B grades whose curves flatten early.
- Most of that fall happens below 2500 rpm.
- 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.
- A substrate of irregular shape needs a slower spin for an even coat.
- 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 does two jobs — it dries the film and it fixes the 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. Hotter and longer both slow the dissolution and tighten the undercut. On a B-series film that lever matters more than on an A grade, because the starting dissolution rate is already high; the published undercut-versus-bake curves (Figures 5a and 5b) are measured on LOR 10B, the nearest B sibling to this grade.
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 7B 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 7B is a PMGI-based sacrificial underlayer from the fast-dissolving B series, spun beneath a conventional photoresist and never exposed itself. The A, B and C series are the same polymer family tuned to different dissolution rates: a B grade opens its undercut faster than an A grade for the same prebake and develop. That is what you want when the deposited film is thick enough to need a generous ledge to break at, and what you do not want when the feature is fine and the undercut would run under it. What makes this grade the useful end of the B line is that it stays sub-micron — 0.32 to 0.90 µm — so you get B-series speed at a thickness the 10B, 15B, 20B and 30B grades would overshoot. Everything that sets the final ledge is a process variable rather than a product property: prebake temperature first, then develop time, then the developer and develop mode. Nothing here is exposed, so there is no dose, no tone and no post-exposure bake.
Grades in this family
Other grades in the LOR B series line differ mainly in coating thickness:
Troubleshooting
Common failure modes for LOR 7B, 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 ledge under LOR 7B runs further than I want. Which knob do I turn?
Two knobs, both named in the datasheet. Develop time is singled out as particularly influential, and the B-series bars, measured on a 3 µm film thicker than any 7B coat, grow from about 3.6 µm of undercut at 2 min to about 9 µm at 3 min. Prebake temperature has the greatest influence on undercut rate, and a hotter bake inside the 160-210 °C window lowers it. For fine patterns, note that the selection guide gives LOR B only some compatibility for 0.35-0.5 µm undercuts.
SOURCE: Kayaku Advanced Materials, "LOR and PMGI Resists" technical…
Kayaku Advanced Materials, "LOR and PMGI Resists" technical data sheet, Rev. D (August 2023) — Soft-Bake/Prebake Process and Figure 5a, p.3; Undercut vs. Develop Time chart, p.4; Product Selection Guide (Undercut Geometry), p.7
How much metal can I lift off over LOR 7B?
Up to roughly 0.68 µm at the slow end. The datasheet wants the underlayer thicker than the deposit, typically by 33 %. LOR 7B coats 0.90 µm at 1000 rpm and 0.32 µm at 4000 rpm, so it carries about 0.68 µm and 0.24 µm of metal at those two ends. The curve is still falling at 4000 rpm (about 0.32 µm), so spin speed is a usable trim across the whole charted range.
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
LOR 7B adheres poorly on a freshly cleaned wafer. Should I prime with HMDS?
Priming is not the fix the datasheet gives. It says primers such as HMDS are typically not required with LOR/PMGI and lists Si, glass, NiFe, III-V materials and Au as compatible substrates. What it asks for is a clean, dry surface: solvent clean or dilute-acid rinse, DI water rinse, then a dehydration bake at 200 °C, 5 min on a contact hotplate or 30 min in a convection oven, before coating 7B.
SOURCE: Kayaku Advanced Materials, "LOR and PMGI Resists" technical…
Kayaku Advanced Materials, "LOR and PMGI Resists" technical data sheet, Rev. D (August 2023) — Features, p.1; Substrate Preparation, p.2; Product Selection Guide (Substrate Compatibility), p.7
Sources & disclaimer
- MicroChem (MCC) — now Kayaku Advanced Materials — LOR 7B 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.